Skip to Main Content

*
Corresponding author e-mail: ganne@get.obs-mip.fr; jerome.ganne@ird.fr.

ABSTRACT

A new and simple integrated approach is proposed for qualitatively unravelling the crustal thickness of fossil magmatic systems based on the chemical and thermal records in amphibole-bearing magmatic rocks. Statistical analyses applied to a large multidimensional amphibole database show that Ti-rich and Si-poor magmatic amphiboles, which formed at high-temperature (T) conditions (>950 °C), were dominantly developed in basaltic to basaltic-andesitic (SiO2-poor, i.e., <55 wt%) magma within relatively thin crust (5–10 km). We find that for crustal thicknesses larger than 10 km, the occurrence of high-T amphiboles and basaltic magma decreases with increasing crustal thickness. This is because of mineral filtering in “mature” deep crustal hot zones that occur at the crust-mantle boundary (Moho). Given that subducting plates exert a direct control on the structural evolution (shortening or extension) of the overriding plates, probing crustal thickness in the past provides first-order information on the geodynamic processes that took place at plate margins. Using this approach, we document the progressive buildup of a thick (>40 km) Jurassic to Cretaceous accretionary belt along the circum-Pacific orogenic belts that bounded the Panthalassa Ocean. The destruction of this thick belt started at ca. 125 Ma and was initially recorded by the thinnest magmatic systems hosting amphibole-bearing magma. Thinning of the circum-Pacific orogenic belts became widespread in the northern regions of western America and in the western Pacific after ca. 75 Ma, possibly in response to oceanic plate segmentation, which triggered slab rollback and overriding plate extension.

INTRODUCTION

Most remnant accretionary belts on Earth are characterized by large exposures of mantle-derived igneous material and only limited occurrences of metamorphic rocks (Cawood et al., 2006). As a result, processes associated with crustal thickening and deformation at plate margins are not fully understood, because their investigations are mainly dependent on classical thermo-barometric tools, such as pseudosections, which are only applicable to metamorphic rocks. In addition, the origin and evolution of the deep crust are normally inferred from exposures of shallower crustal sections, and this results in major uncertainties regarding the pressure (P), temperature (T), and deformation history of accretionary belts.

Accounting for these limitations, various geochemical indices (Leeman, 1983; Plank and Langmuir, 1988) have been proposed as proxies for probing crustal thickness in magmatic arcs (Mantle and Collins, 2008; Zellmer, 2008, Chiaradia, 2014; Chapman et al., 2015; Profeta et al., 2015). Such proxies are based on tens of thousands of analyses of magmatic rocks covering most of Earth’s history, and uncovering patterns and temporal variations using data mining techniques. However, none of these proxies has hitherto been tested against the mineral, thermal, and chemical records of magma, which, together, integrate many of the high-frequency variations and complex details that can exist in magmatic systems. Such an approach is possible through the examination of crystallization conditions of hydrous magmatic minerals, such as amphiboles, which could provide petrological and temperature constraints on the control of crustal thickening on magma evolution (Rutherford and Devine, 2003; Hawthorne et al., 2007; Larocque and Canil, 2010; Ridolfi and Renzulli, 2012; Erdmann et al., 2014; Putirka, 2016).

In this paper, we propose a new integrated approach for qualitatively unravelling the crustal thickness of fossil magmatic systems based on the chemical and thermal records of magma. We refer to “thin” or “thick” magmatic systems based on the crustal thickness (oceanic or continental) on which the arc magmatism was constructed (i.e., we do not refer to the size or volume of the magmatic reservoirs within the crust). We first outline several lines of evidence that arise from petrological analyses and geochemical modeling in magmatic systems hosting amphiboles. We present a multidimensional database of magmatic rocks and minerals, and we explore the sensitivity of different chemical, mineral, and thermal parameters to crustal thickness in young (younger than 10 Ma) igneous rocks. We then test the empirical correlations on a number of ancient subduction margins within the circum-Pacific orogenic belts, for which there are independent constraints on crustal thickness variations through time. In a broader geodynamic context, the new integrated approach sheds light on the growth of a thick (>40 km) Jurassic to Cretaceous accretionary belt along the circum-Pacific orogenic belts and its subsequent destruction.

GENERAL BACKGROUND

Magma Differentiation

Crustal thickening in convergent plate margins has profound effects on the chemical evolution of SiO2-poor mantle-derived basalts toward SiO2-rich evolved intermediate to felsic magmas (Miyashiro, 1974; Atherton and Petford, 1993; Tepper et al., 1993; Sisson and Bacon, 1999; Dungan and Davidson, 2004; Mamani et al., 2010; Turner et al., 2012). This evolution is classically explained through the concept of fractional crystallization (DePaolo, 1981) and/or dehydration crustal melting processes (Hildreth and Moorbath, 1988). The efficiency of such processes at middle to shallow crustal levels has been discussed based on geochemical and thermodynamic modeling (Spera and Bohrson, 2001; Glazner, 2007; Clemens et al., 2009; Kratzmann et al., 2010). It has recently been suggested that the geochemical signatures of magmas are preferentially acquired deepest in the crust (Lee et al., 2014) and that early-formed high-P mineral assemblages trapped at the bottom of thickening arcs (Barclay and Carmichael, 2004; Davidson et al., 2007, 2013) could exert a first-order control on magma differentiation (Rutherford and Devine, 2003; Giesting and Filiberto, 2014; Dessimoz et al., 2012; Chiaradia, 2014). The boundary between the lower crust and the upper mantle (Moho) represents a mechanical threshold that favors accumulation of mantle-derived basalt, crystallization, and residual melt segregation, possibly into deep hot zones (Ernst, 1999; Annen and Sparks, 2002; Annen et al., 2006). Other models that attribute the chemical variability of arc magmas to slab or wedge processes are discussed in Turner and Langmuir (2015).

Amphibole in Magma

Magmatic amphiboles are considered to represent either (1) primary minerals formed after relatively low-T melting of a hydrous mantle above a dehydrating subducting slab, or (2) secondary phases formed after crystallization of evolved hydrous silicate melts (Tribuzio et al., 2014), which commonly exsolve from magmas upon crystallization (Coogan et al., 2001; Smith, 2014). Uncertainties surrounding the genesis of magmatic amphiboles have stimulated many experimental studies (Allen and Boettcher, 1983; Sisson and Grove, 1993; Wallace, 2005; Larocque and Canil, 2010), and there is a general agreement that changes in temperature (Ti-and Al-tschermak exchanges: Hammarstrom and Zen, 1986; Hollister et al., 1987; Johnson and Rutherford, 1989; Schmidt, 1992; Anderson and Smith, 1995; Anderson et al., 2008) and magma compositions (Sisson and Grove, 1993; Pichavant et al., 2002) affect the composition of magmatic amphiboles.

The origin of high-Si amphiboles (hence low-Al and low-Ti amphiboles; Putirka, 2016) is classically interpreted as forming in a shallow magmatic reservoir made of evolved (felsic) melts (Grove et al., 2003). This magmatic reservoir may be injected by hot and less-evolved (mafic) melts coming from the deepest magmatic reservoirs, resulting in a mixing of magmas (e.g., Humphreys et al., 2009). Mafic melts will form a new generation of low-Si amphiboles in the shallow magmatic reservoir, destabilizing the early generation of high-Si amphiboles (Erdmann et al., 2014; Kiss et al., 2014). The intrinsic sensitivity of amphibole to temperature and melt composition, rather than pressure (Putirka, 2016), makes the usage of natural amphibole for geobarometry rather controversial, particularly in the absence of careful examination of equilibrium textures (i.e., homogeneous composition or normal zonings; Ague, 1997; Manley and Bacon, 2000; Lindsay et al., 2001; Bachmann et al., 2002; Janoušek et al., 2004; Blundy et al., 2006; Zhang et al., 2006; Rodríguez et al., 2007; Anderson et al., 2008; Needy et al., 2009; Samaniego et al., 2008; Ruprecht and Bachmann, 2010; Turnbull et al., 2010). Nonetheless, the potential of amphibole as a geothermometer is generally accepted (Bachmann and Dungan, 2002; Shane and Smith, 2013). For this reason, we largely based our conclusions on the chemical composition of amphiboles and magma, rather than the P-T estimates.

METHODOLOGY AND APPROACH

What Is a “Mean” in Petrology?

Sampling is the basis of all work in earth science disciplines, even as diverse as they are. In petrology, the sample on which we base our thinking is seen as part of a whole, chosen to represent one or more characteristic properties of that set: but is it really the case? All sampling, even the simplest, is subject to several sources of error related to the sampling technique, the way in which that particular technique is applied, or to the instrument used for sampling. When the volume of the sample is too large, it must be down sampled to only analyze a small portion of the sample. The risk of selecting the most spectacular subsample, distorting the representation of this set, is omnipresent. Each step of down sampling implies an error, and these errors accumulate, altering our perception of an event or a geological process. Geostatistics can help to quantify the magnitude of these errors, but work on quite large data sets often extracts an average value (“mean”). The estimated mean of a variable is only possible if we measured this variable on large numbers of samples. Thus, the quantity and quality of sampling influence that of the “mean” itself. There is no need to develop sophisticated estimation techniques if the database is not reliable. The multiscale processing of these data is a relatively recent approach in earth sciences, arising from the need to take into account all phenomena, in practice coupled, that have acted on (or are present in) a given system. This is the most complete form of modeling of a sequence of various phenomena proceeding at different orders of magnitude, since it integrates, at different scales, all theoretical or empirical knowledge in elementary bricks that need to be assembled.

Recent advances in the domain of igneous petrology (Ghiorso and Sack, 1995; Herzberg and Asimow, 2008; Putirka, 2008) have occurred along with the development of chemical databases of magmatic rocks and minerals, providing access to several tens of thousands rocks and minerals analyses spanning most of Earth’s history. Data mining techniques allow the exploration of these data sets to uncover hidden patterns and trends over time periods of several tens to hundreds of millions of years, matching those of geodynamics (Keller and Schoene, 2012; Tang et al., 2016). As they incorporate a growing number of data, the results of these new global studies are surrounded by a statistical dimension out of necessity, which makes them quite unpopular in the scientific community of petrologists. Yet, these new approaches are necessary because they capture the geological signals at longer wavelengths, smoothing the analytical errors, filling the sampling bias, and averaging values along secular trends. Accordingly, the “petrological mean” computed from these studies has a real meaning because it fully accounts for (and does not mask) the natural variability in petrology that arises from variable temperatures (and depths) of partial melting and crystallization in igneous rocks from widely different geological environments (arcs, cratonic provinces, oceans, etc.). Here, we opted for this integrated approach, and we emphasize that our conclusions can only provide dominant trends rather than strict rules.

Database and Statistical Approach

We used an extensive geochemical data set of continental and oceanic igneous rocks and minerals (amphibole, pyroxene, plagioclase, and olivine) from the Phanerozoic to Archean. Data from the GEOROC database (https://www.georoc.mpch-mainz.gwdg.de/georoc/) were compiled by Ganne et al. (2016), using published and unpublished data, and then filtered to exclude all samples for which the summed oxides yielded totals outside the 95%–101.5% range. Geochronological data associated with these samples were reported as means, with 1-standard-error uncertainty given by the method (e.g., U/Pb geochronology or biostratigraphy). Georeferenced bulk-rock chemistry and mineral analyses (3646 references) were used to derive P and T estimates. The resulting data set includes a total of more than 16 million data points, with up to 130 variables for each of the >55,000 rock samples and 80 variables for each of the >117,000 mineral analyses. Results for global mean intensive (geochemical) and extensive (P, T) values with time are reported with associated 1-standard-error uncertainties of the mean at 50 m.y. intervals. These means were generated by Monte Carlo analysis, using the standard bootstrap resampling approach outlined in the following.

Our approach follows Keller and Schoene (2012), with information from the original source added where necessary. The following procedure was conducted: (1) A subset of data was randomly selected such that the probability of inclusion in the resampled subset was directly proportional to the sample weight; (2) a synthetic data set for each sampled data point was drawn from a Gaussian distribution with a mean equal to the original value of the data point and the standard deviation equal to the estimated 1-standard-error uncertainty for the data point; (3) the resulting data were sorted into 50 m.y. bins, with a mean and variance calculated for each variable; (4) steps 1–3 were repeated 1000 times, where a minimum number of samples (threshold of 3) within each 50 m.y. bin was fixed for steps 1–3; and (5) the total mean and standard error of the mean were calculated for each variable in each bin. Results are reported as means with associated 1-standard-error uncertainty of the mean for 50 m.y. intervals between 0 and 300 Ma.

In contrast to the approach of Keller and Schoene (2012), which attempted to produce a uniform record by reducing the weight of abundantly sampled time periods or terranes, our sampling was not assigned to be inversely dependent on spatial and/or temporal sample density. Similarly, uncertainties surrounding the age of samples were not considered in our statistical approach, as this standard error is not homogeneous and depends on the method of dating used. Uncertainties surrounding ages are less than 50 m.y. for >5% of the magmatic samples, with a mean of ~15 m.y. Uncertainties are thus lower than the results of bootstrap that we reported as means for 50 m.y. intervals, and thus are not likely to change our general conclusions on the chemical evolution of magmas and minerals through geological time. Our Monte Carlo analysis likely results in a more discontinuous geochemical record compared with the statistical approach of Keller and Schoene (2012), which smoothed out stochastic and stepwise transitions; the slopes of any abrupt trends presented in the diagrams are therefore maximum estimates. Overall, we assume that the robustness of our statistical approach is strengthened by the negligible occurrence of sampling gaps for magma and mineral record in the database, more specifically between 0 and 300 Ma.

Thermometry Using Magmatic Amphibole

The database contains compositional analyses of 12,484 amphiboles compiled from the literature (25%), GEOROC (46%), and unpublished data (29%), 50% of which were matched with their bulk-rock chemistry (1438 samples; major and trace elements). Structural formulae for amphiboles were calculated using the Probe-Amph excel program (Tindle and Webb, 1994). Figure 1 presents microprobe analyses from the database. A chemical evolution can be observed between the most Si-depleted amphibole (ferropargasite or ferrotschermakite end members according to the [Na + K]A value), which are characterized by high-Fe contents, and the Si-enriched amphiboles (magnesiohornblende or edenite), which are characterized by elevated Mg contents (Ridolfi and Renzulli, 2012; Putirka, 2016).

Figure 1. Distribution of the magmatic calcic-amphiboles (3223 analyses) shown in classification tables (after Leake et al., 1997). Structural formulae of amphiboles were calculated using the Probe-Amph Excel program of Tindle and Webb (1994). Also shown, for each data point, are temperature (A) and pressure (B) conditions of amphibole crystallization (based on the method of Ridolfi and Renzulli, 2012).

Figure 1. Distribution of the magmatic calcic-amphiboles (3223 analyses) shown in classification tables (after Leake et al., 1997). Structural formulae of amphiboles were calculated using the Probe-Amph Excel program of Tindle and Webb (1994). Also shown, for each data point, are temperature (A) and pressure (B) conditions of amphibole crystallization (based on the method of Ridolfi and Renzulli, 2012).

In this study, we used a new Al-based coupled thermobarometer model (Ridolfi and Renzulli, 2012; RR2012) built on an extensive synthesis of literature and new experimental data on magmatic amphiboles. Recent studies (Yücel et al., 2013; Kent, 2014; Erdmann et al., 2014) have shown that temperature estimates obtained by the RR2012 method are consistent with the amphibole-plagioclase thermometer (Holland and Blundy, 1994; Blundy and Holland, 1990). However, the confidence of the calculated pressure estimates is less robust (Putirka, 2016). Ideally, each amphibole should be checked for equilibrium textures (i.e., homogeneous composition or normal zonings) before using the RR2012 method (Ridolfi and Renzulli, 2012), because reverse zonings are likely to indicate magma mixing in an environment with a high rheological and viscosity contrast that can lead to overestimated pressure (Tajčmanová, et al., 2014; Moulas et al., 2014). Unfortunately, in the compiled literature (>900 references), information on equilibrium textures is commonly absent.

Chemical data collected on magmatic amphiboles were filtered on the basis of pressure-related “apparent percentage error” (APE) values calculated with the RR2012 thermobarometric method. Following the recommendation of Ridolfi and Renzulli (2012), a maximum of 50 for the APE was set to retain or exclude the data (first filter: moderate confidence level). To secure our estimates, a second filter (high confidence level) was applied, leading to exclusion of amphiboles for which the chemistry did not fit the dedicated range of chemical composition and structural formulae. More than 70% of the calcic-amphiboles in our database were discarded.

RESULTS

Magma as a Proxy for Crustal Thickness

Major-and trace-element signatures of Cenozoic magmas in plate margins show significant along-strike variations that correspond to changes in crustal thickness (Zellmer, 2008; Turner and Langmuir, 2015). Furthermore, it appears that early-formed minerals trapped at the bottom of thickening arcs (Davidson et al., 2007) could exert a first-order control on the magma differentiation trends (tholeiitic vs. calc-alkaline; Miyashiro, 1974). Accounting for this mechanism of mineral fractionation within the crust, various geochemical indices have been proposed as proxies for probing crustal thickness in magmatic arcs, with a representative list given in Chapman et al. (2015). The tholeiitic (Th) index proposed by Chiaradia (2014; more Fe2O3 total-enriched at MgO ~4–6 wt%) is based on the observation that the thinner the magmatic arc, the more mafic and tholeiitic (Th index of ~11–12) is the magma (Chiaradia, 2014). Elevated water content and fO2 in the deep section of thick crusts lead to a more calc-alkaline composition (Th index of ~7–8) through suppression of plagioclase fractionation and promotion of early magnetite and amphibole fractionation (Sisson and Grove, 1993).

Figures 2 and 3 show that crustal thickness exerts a first-order control on the composition of magmas, which become more calc-alkaline and felsic with increasing crustal thickness. We achieved this by compiling a comprehensive database for the geochemistry of magmas from relatively young rocks (younger than 10 Ma) for which the crustal thickness is known (Mooney et al., 1998). While Chiaradia (2014) or Profeta et al. (2015) focused their studies on arc settings, here we looked for more global correlations between crustal thickness and young magma compositions that were likely produced through a variety of magmatic processes and involving different geological settings (i.e., continental arcs, intraplate magmatism, rift, orogenic belts, etc.). For each data point, we plotted the corresponding crustal thickness hosting the magma, thus allowing us to explore relationships between the chemical signature of magma and crustal thickness. We minimized errors induced by a possible thickening of crust following magma emplacement by discarding data older than ca. 10 Ma. The magma series considered along northwestern and southwestern America (Fig. 3) covers the compositional range of basalts to rhyolites and their intrusive equivalents (40–75 wt% SiO2).

Figure 2 shows that the Th index of magma and associated SiO2 (wt%) range around values of ~10 and 55, respectively, for crustal thickness ranging from 25 to 40 km. As a consequence, no good precision can be obtained when probing the crustal thickness of magmatic belts in which the magma evolved in the past within this range of Th index and SiO2 (wt%) composition. Beyond this threshold, the Th index strongly decreases with increasing crustal thickness and SiO2 wt% of the magmatic rocks, but again less confidence can be given to these values because they are not supported by high-density data. This limitation questions the validity of an approach that solely relies on a single magma proxy to depict crustal thickness in the past, as well as the real quantitative significance of values obtained in orogenic belts that reached a crustal thickness exceeding 45 km. As an extension of that conclusion, Figure 3 shows that two major elemental concentrations (SiO2 wt% and Th index) can be used conjointly as crustal thickness proxies and yield consistent results when larger global and regional data sets are averaged out.

Amphibole as a Proxy for Crustal Thickness

Given that magma compositions affect the composition of magmatic amphiboles (Sisson and Grove, 1993; Pichavant et al., 2002), the amphiboles could be potentially used as a complementary proxy for crustal thickness. We again approached this issue by compiling a comprehensive database of the geochemistry of geologically young amphiboles (younger than 10 Ma) and their hosting magmas, together with information on crustal thickness (Mooney et al., 1998). Results for global mean intensive (geochemical) and extensive (P, T) values, and corresponding crustal thicknesses, are reported in Figure 4. Plots of the variability of T and P conditions of amphibole crystallization versus their chemical composition (Ti and Si atoms per formula unit [apfu]) or the chemical composition of the hosting magma (SiO2 [wt%]) are shown in Figures 5 and 6.

Figure 2. (A) Chemical evolution (SiO2, wt%) of magmas emplaced along the circum-Pacific orogenic belts (CPOB; western and eastern Pacific) according to their age. A polynomial curve (N = 5) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 50 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. R2 corresponds to the coefficient of determination associated with the polynomial curve. (B, C) Correlation between the gradual occurrence or decrease (statistical assessment) of siliceous and tholeiitic magmas (Th index: averages of median Fe2O3 total values corresponding to the 4–6 wt% MgO interval; Chiaradia, 2014) and the crustal thickness where young Cenozoic magmatism (ca. 10–0 Ma) took place. Tholeiitic magmas dominantly developed in mafic (SiO2-poor) magma in the thinnest crustal sections (<20 km). Th index and mafic magma decrease with increasing crustal thickness, although no clear correlation (flat-lying curve, gray area on the graph) can be observed for crustal thickness ranging between ~25 and 40 km. Beyond this threshold, less confidence can be given to the bootstrapped values (green area), due to the lack of data in the geological record (see Fig. 5A). (D) Chemical evolution (Th index) of magmas emplaced along the circum-Pacific orogenic belts (western and eastern Pacific) according to their age. The data illustrate a decrease of tholeiitic magma occurrence in Jurassic to Late Cretaceous times (ca. 75 Ma). Beyond this threshold, the density of data increases (higher confidence level), along with the Th index of magmas. Trias—Triassic.

Figure 2. (A) Chemical evolution (SiO2, wt%) of magmas emplaced along the circum-Pacific orogenic belts (CPOB; western and eastern Pacific) according to their age. A polynomial curve (N = 5) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 50 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. R2 corresponds to the coefficient of determination associated with the polynomial curve. (B, C) Correlation between the gradual occurrence or decrease (statistical assessment) of siliceous and tholeiitic magmas (Th index: averages of median Fe2O3 total values corresponding to the 4–6 wt% MgO interval; Chiaradia, 2014) and the crustal thickness where young Cenozoic magmatism (ca. 10–0 Ma) took place. Tholeiitic magmas dominantly developed in mafic (SiO2-poor) magma in the thinnest crustal sections (<20 km). Th index and mafic magma decrease with increasing crustal thickness, although no clear correlation (flat-lying curve, gray area on the graph) can be observed for crustal thickness ranging between ~25 and 40 km. Beyond this threshold, less confidence can be given to the bootstrapped values (green area), due to the lack of data in the geological record (see Fig. 5A). (D) Chemical evolution (Th index) of magmas emplaced along the circum-Pacific orogenic belts (western and eastern Pacific) according to their age. The data illustrate a decrease of tholeiitic magma occurrence in Jurassic to Late Cretaceous times (ca. 75 Ma). Beyond this threshold, the density of data increases (higher confidence level), along with the Th index of magmas. Trias—Triassic.

Figure 3. Chemical record (SiO2 [wt%] and Th index) of magmatic rocks plotted against the geographic position of Cenozoic-aged samples (ca. 10–0 Ma) along the eastern parts of the circum-Pacific orogenic belts (CPOB; >6850 analyses). Mafic rocks are less abundant in Peru–north Chile magmatic systems, which were developed on a thick continental crust (60 km in the Altiplano area [A]) and more abundant along the Northern American Cordilleras (Coast Mountains [CM] and Sierra Nevada [SN]) and south Chile–Patagonia magmatic systems, where the continental crust is thinnest (<30 km). Four isodepth contours (30, 40, 45, and 50 km) are shown on the map based on the global crustal model (2 × 2 degrees) CRUST 2.0 (Mooney et al., 1998; Bassin et al., 2000).

Figure 3. Chemical record (SiO2 [wt%] and Th index) of magmatic rocks plotted against the geographic position of Cenozoic-aged samples (ca. 10–0 Ma) along the eastern parts of the circum-Pacific orogenic belts (CPOB; >6850 analyses). Mafic rocks are less abundant in Peru–north Chile magmatic systems, which were developed on a thick continental crust (60 km in the Altiplano area [A]) and more abundant along the Northern American Cordilleras (Coast Mountains [CM] and Sierra Nevada [SN]) and south Chile–Patagonia magmatic systems, where the continental crust is thinnest (<30 km). Four isodepth contours (30, 40, 45, and 50 km) are shown on the map based on the global crustal model (2 × 2 degrees) CRUST 2.0 (Mooney et al., 1998; Bassin et al., 2000).

Figure 4. (A, B) Chemical composition of amphiboles plotted against the thickness of the crust (Mooney et al., 1998) where young Cenozoic magmas (ca. 10–0 Ma), hosting these amphiboles, were emplaced (>3000 analyses, 141 bibliographic references). Ti-rich (>0.25 apfu) and Si-depleted (<6 apfu) magmatic amphiboles dominantly developed in mafic (SiO2-poor, <55 wt%: blue point) magma in the thinnest crustal sections. Si-depleted and Ti-rich record of amphiboles and mafic magma decreases with increasing crustal thickness. Ti-poor (<0.2 apfu; see Fig. 4B) and Si-rich (>6.2 apfu; see Fig. 4A) magmatic amphiboles dominantly developed in felsic (SiO2-rich >65 wt%; see Fig. 4A) magma in the thickest crustal sections. A polynomial curve (N = 4–6) fitting the bootstrapped values (1000 draws, threshold value of 3, crust step of 5 km, uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. R2 corresponds to the coefficient of determination associated with the polynomial curve. (C) The control of crustal thickness on magma composition was also investigated by statistical analysis (gray points on the graph correspond to analyses from magmas hosting amphiboles; 446 points). It shows that the thicker the (arc) crust, the less mafic is the bulk-rock chemistry. (D, E) Temperature (T) and pressure (P) conditions of amphibole crystallization using the RR2012 (Ridolfi and Renzulli, 2012) method. It confirms that the number of moderate-(>5 kbar) to high-P (>8 kbar) and high-T (> 950–1000 °C) amphiboles decreases with crustal thickening.

Figure 4. (A, B) Chemical composition of amphiboles plotted against the thickness of the crust (Mooney et al., 1998) where young Cenozoic magmas (ca. 10–0 Ma), hosting these amphiboles, were emplaced (>3000 analyses, 141 bibliographic references). Ti-rich (>0.25 apfu) and Si-depleted (<6 apfu) magmatic amphiboles dominantly developed in mafic (SiO2-poor, <55 wt%: blue point) magma in the thinnest crustal sections. Si-depleted and Ti-rich record of amphiboles and mafic magma decreases with increasing crustal thickness. Ti-poor (<0.2 apfu; see Fig. 4B) and Si-rich (>6.2 apfu; see Fig. 4A) magmatic amphiboles dominantly developed in felsic (SiO2-rich >65 wt%; see Fig. 4A) magma in the thickest crustal sections. A polynomial curve (N = 4–6) fitting the bootstrapped values (1000 draws, threshold value of 3, crust step of 5 km, uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. R2 corresponds to the coefficient of determination associated with the polynomial curve. (C) The control of crustal thickness on magma composition was also investigated by statistical analysis (gray points on the graph correspond to analyses from magmas hosting amphiboles; 446 points). It shows that the thicker the (arc) crust, the less mafic is the bulk-rock chemistry. (D, E) Temperature (T) and pressure (P) conditions of amphibole crystallization using the RR2012 (Ridolfi and Renzulli, 2012) method. It confirms that the number of moderate-(>5 kbar) to high-P (>8 kbar) and high-T (> 950–1000 °C) amphiboles decreases with crustal thickening.

Figure 5. Pressure and temperature conditions of amphibole crystallization, calculated with the RR2012 (Ridolfi and Renzulli, 2012) method, plotted against their chemical composition (3223 analyses). (A) Ti (apfu) content in amphibole showing the dominant control of temperature on the Ti-tschermak substitution. (B) Si (apfu) content in amphibole showing the dominant control of pressure on the Al-tschermak substitution. The data suggest that high-Ti and low-Si amphiboles are stable at higher temperature and pressure conditions.

Figure 5. Pressure and temperature conditions of amphibole crystallization, calculated with the RR2012 (Ridolfi and Renzulli, 2012) method, plotted against their chemical composition (3223 analyses). (A) Ti (apfu) content in amphibole showing the dominant control of temperature on the Ti-tschermak substitution. (B) Si (apfu) content in amphibole showing the dominant control of pressure on the Al-tschermak substitution. The data suggest that high-Ti and low-Si amphiboles are stable at higher temperature and pressure conditions.

Figures 4A and 4B show that the formation of Si-poor (<6 apfu) and Ti-rich (>0.25 apfu) magmatic amphiboles occurs at high-temperature conditions (>950 °C; Figs. 4D, 6A, and 6B). Likewise, such amphiboles dominantly develop in basaltic to basaltic-andesitic composition (SiO2-poor, i.e., <55 wt%) magma emplaced in crustal sections thinner than 10 km (blue point in Fig. 4B). Beyond these values, high-T amphiboles in magma decrease with increasing crustal thickness to average Ti values lower than 0.2 apfu at ~40 km depth, accompanied by a narrower range of magma composition toward andesite to dacite compositions (>60 wt%). Statistical approaches (bootstrapping; Fig. 4B) applied to the large multidimensional amphibole database confirm that with increasing crustal thickness, the abundance of Tirich and Si-poor amphibole decreases (lower temperature and lower pressure; Figs. 4D and 4E) and the magmatic system contains less mafic rock in proportion (Fig. 4C).

Using chemical and thermal records of amphibole and magma as compelling markers, we propose an integrated approach to unravel the crustal thickness evolution of fossil magmatic systems. P estimates are less reliable (see Method section) and were not considered in this study. Figures 2 and 4 provide a simple basis to identify past, overthickened (>40 km) magmatic systems hosting “mature” deep crustal hot zones (Annen et al., 2006), based on the limited Ti-dependent temperature (<900 °C) and Si-dependent pressure (<3 kbar) record of magmatic amphiboles, and the dominant occurrence of andesitic to dacitic magmas (SiO2 > 60 wt%) sharing calc-alkaline affinity (Th index < 10). In addition, identification of thin (>10 km) magmatic systems hosting “immature” deep crustal hot zones relied on the limited Ti-dependent temperature (>950 °C; blue point in Figs. 4D, 5, and 6) and Si-dependent pressure (>5 kbar; Fig. 4E) record of magmatic amphiboles, and the dominant occurrence of basaltic to basaltic-andesitic magmas (SiO2 < 55 wt%; Figs. 4A and 4C) sharing tholeiitic affinity (Th index > 10).

Figure 6. Statistical analysis to explore the variability of temperature (T) and pressure (P) conditions of amphibole (3223 analyses) crystallization vs. their chemical composition (Ti and Si apfu). T and P conditions, calculated with the RR2012 (Ridolfi and Renzulli, 2012) method, were bootstrapped (resampling method: 1000 draws, threshold value of 3, step of 10 °C and 10 bars, respectively). Temperature (A, B), and to a lesser extent pressure (D, E), seem to exert a first-order control on the Ti and Si composition of magmatic amphibole. The data suggest that high-Ti (>0.25 apfu) and low-Si (<6 apfu) amphiboles are stable at temperature and pressure above 950 °C and 5 kbar, respectively (blue point). Low-Ti (<0.2 apfu) and high-Si (>6.2 apfu) amphiboles are stable at temperature and pressure lower than 900 °C and 3 kbar, respectively. (C) Chemical composition (Ti apfu content) of amphiboles according to their bulk-rock composition (SiO2, wt%). A negative correlation (statistical assessment) with the Si content of the magmatic rock is observed.

Figure 6. Statistical analysis to explore the variability of temperature (T) and pressure (P) conditions of amphibole (3223 analyses) crystallization vs. their chemical composition (Ti and Si apfu). T and P conditions, calculated with the RR2012 (Ridolfi and Renzulli, 2012) method, were bootstrapped (resampling method: 1000 draws, threshold value of 3, step of 10 °C and 10 bars, respectively). Temperature (A, B), and to a lesser extent pressure (D, E), seem to exert a first-order control on the Ti and Si composition of magmatic amphibole. The data suggest that high-Ti (>0.25 apfu) and low-Si (<6 apfu) amphiboles are stable at temperature and pressure above 950 °C and 5 kbar, respectively (blue point). Low-Ti (<0.2 apfu) and high-Si (>6.2 apfu) amphiboles are stable at temperature and pressure lower than 900 °C and 3 kbar, respectively. (C) Chemical composition (Ti apfu content) of amphiboles according to their bulk-rock composition (SiO2, wt%). A negative correlation (statistical assessment) with the Si content of the magmatic rock is observed.

As an extension of that work, we tested the sensitivity of the SiO2 (wt%) content in the magma to crustal thickness variation when amphibole is present (Fig. 7). The results illustrate that amphibole-bearing magmas occur in thinner magmatic systems (~25 km; Fig. 7C) compared to the average magma record (~28 km; Fig. 7C). Accounting for this pattern, we speculated that the progressive thinning of magmatic systems operating along this margin would result in the coalescence of shallow, intermediate, and deep-seated magmatic reservoirs (“deep hot zones”) in the crust into a single reservoir where mantle-derived tholeiitic magmas would not evolve significantly (Fig. 7D). Figure 7A shows that magma containing amphiboles (e.g., amphibole-bearing) yields more felsic compositions compared to those that do not contain amphibole (amphibole-free), regardless of the crustal thickness (e.g., for crustal sections <10 km, amphibolebearing and amphibole-free magma will contain 55 and 50 wt% SiO2, respectively). The corollary is that any change in thickness for magmatic systems will be first recorded by the amphibole-bearing magmas, changing their chemistry from felsic to mafic composition. It is thus expected that they will record the early steps of continental extension, promoting an incipient increase of the mafic magma, and then Ti-rich amphibole in the geological record. At a late stage, further extension of the continental crust will result in the general thinning of magmatic systems (amphibole-bearing and amphibole-free) and a more extensive record of mafic magma in the geological record (Mantle and Collins, 2008; Zellmer, 2008; Chiaradia, 2014; Chapman et al., 2015; Profeta et al., 2015).

DISCUSSION

Crustal Evolution of the Circum-Pacific Orogenic Belts

Unravelling the paleothickness of magmatic systems provides first-order information on the geodynamic history of subduction zone plate margins, which are known to be subject to transient switches in the style of overriding plate deformation (shortening or extension; e.g., Schellart et al., 2010). Here we focus on the circum-Pacific orogenic belts (Figs. 8 and 9), which constitute the largest, most long-lived, and still operational accretionary orogenic systems in the world (Collins et al., 2011). The Phanerozoic evolution of the circum-Pacific orogenic belts records the assembly and breakup of the last supercontinent, Pangea. Our database in the GSA Data Repository1 reveals an increasing occurrence of tholeiitic magma during the Cenozoic, which contrasts with the calc-alkaline affinity throughout the Jurassic and Cretaceous (Fig. 2D).

In our analysis, samples were filtered according to their geographic position along the circum-Pacific orogenic belts (western and eastern Pacific), and their SiO2 contents (wt%) were plotted against their age of crystallization. A negative correlation (i.e., chemical element decreasing with age) is observed from ca. 175 to 75 Ma in the western Pacific, with the youngest rocks showing the highest SiO2 contents (wt%) and calc-alkaline compositions (Fig. 9C). Beyond this threshold, a positive correlation is observed (i.e., chemical element increasing with age). Interestingly, the peak of SiO2 (>63 wt%) for magmas at ca. 75 Ma (yellow trend in Fig. 9C) is preceded by an increasing occurrence of Ti-rich amphibole in the amphibole-bearing magmatic systems since ca. 125 Ma (black trend in Fig. 9B). In order to better visualize average trends for amphibole, we applied a statistical treatment of data, with large (50 m.y.) and small (10 m.y.) sampling steps (Figs. 9 and 10). Considering the tectonic context, we recognize relationships between crustal thinning of amphibole-magmatic systems and the orogenic events that occurred in the western Pacific region after ca. 75 Ma. This chemical evolution of amphibole-bearing magma toward more mafic (SiO2-poor) composition started at ca. 125 Ma (green trend in Fig. 9C), preceding the onset of continental extension in the SW Pacific (ca. 90–70 Ma; Schellart et al., 2006; Mantle and Collins, 2008) and East Asia (ca. 70–55 Ma; Northrup et al., 1995; Ren et al., 2002; Schellart and Lister, 2005), and accompanied the process of seafloor spreading that took place around ca. 30 Ma around the Japan Sea (Fig. 10; Yoshiyuki et al., 1989).

This chemical trend is equally pronounced in the eastern Pacific. Rocks were arbitrarily filtered according to their actual latitudinal position, allowing us to define two subgroups: (1) North (latitudes north of to 30°N) and Central America (from 30°N to 10°S), and (2) South America (latitudes south of 10°S). A positive correlation was observed in North and Central America from ca. 175 Ma to present (Fig. 11A), with the youngest rocks showing highest SiO2 contents (wt%) and a more calcalkaline composition. This could correspond to a progressive thickening of the Mesozoic coastal belts (Coney et al., 1980; van der Heyden, 1992) from the Nevadan to Sevier-Laramide orogeny and their thinning in the Cenozoic. However, metamorphic studies performed along the Cordilleran belts (Ducea, 2001, and reference therein) argue for a thick crustal section (>40 km) at the time of the Sevier-Laramide orogeny. This hypothesis is supported by the narrow range of amphibole composition (averaged Ti content < 0.2 apfu) characterizing the Pioneer plutonic complex in southwest Montana (Zen, 1985; Hammarstrom and Zen, 1986; Fig. 3). In order to explore the progressive thickening of the Mesozoic coast belts discussed by Chapman et al. (2015) and Profeta et al. (2015), we reused the amphibole database of Hammarstrom (1984) compiled from four Mesozoic batholiths of northwestern America (SW Montana, British Columbia, SE Alaska, Idaho: white stars in Figs. 3 and 12A) and dated from ca. 117 to 70 Ma, respectively (Murphy et al., 2002; Saleeby and Rubin, 2000; Jeffcoat, 2013). Interestingly, no clear evidence of crustal thickening evolution of the amphibole-bearing magmatic systems is recognized for the Cretaceous. The progressive thickening of amphibole-bearing magmatic systems developed earlier, at ca. 200–150 Ma, involving the ca. 200–180 Ma Talkeetna oceanic arc in south-central Alaska (Armstrong, 1988; Greene et al., 2006; black star in Fig. 12A) that formed a crustal section <28 km thick (Hacker et al., 2008) in an oceanic domain (Sigloch and Mihalymuk, 2013) and was later accreted along the circum-Pacific orogenic belts (Coney et al., 1980). This Jurassic evolution was followed by progressive thinning of the amphibole-bearing magmatic systems, from ca. 125 Ma to present day, corresponding to a change from Nevadan to Sevier-Laramide orogeny to Basin and Range extension. A statistical treatment of data from the Sierra Nevada (du Bray, 2007), using a small sampling step (1 m.y.), helped to better visualize the increase of mafic magma record in the last 20 m.y. (Basin and Range extension; Fig. 11C).

Figure 7. (A) Chemical composition of magmas (light-gray points) plotted against crustal thickness (Mooney et al., 1998) where young Cenozoic magmas (ca. 10–0 Ma) were emplaced (>19,000 analyses). The amphibole-bearing magma record is given by the dark-gray points. Data illustrate that amphibole-bearing magmatic systems developed in a large range of crustal thicknesses (<10–60 km), forming magmas with more SiO2-rich composition (red curve) compared to the average magma record (black curve). (B, C) Comparative distribution of crustal thickness where Cenozoic-aged (ca. 10–0 Ma) magmatic rocks have been sampled. (D) Schematic three-dimensional model of active margin undergoing overriding plate extension. It is expected that the thinnest magmatic systems (e.g., the amphibole-bearing ones) will record the early steps of the continental extension, promoting an incipient increase of the Ti-rich amphibole in the geological record. At a late stage (ca. 50 Ma in western Pacific; Fig. 9C), further extension of the continental crust will result in the general thinning of all magmatic systems and the extensive record of mafic magma in the geological record.

Figure 7. (A) Chemical composition of magmas (light-gray points) plotted against crustal thickness (Mooney et al., 1998) where young Cenozoic magmas (ca. 10–0 Ma) were emplaced (>19,000 analyses). The amphibole-bearing magma record is given by the dark-gray points. Data illustrate that amphibole-bearing magmatic systems developed in a large range of crustal thicknesses (<10–60 km), forming magmas with more SiO2-rich composition (red curve) compared to the average magma record (black curve). (B, C) Comparative distribution of crustal thickness where Cenozoic-aged (ca. 10–0 Ma) magmatic rocks have been sampled. (D) Schematic three-dimensional model of active margin undergoing overriding plate extension. It is expected that the thinnest magmatic systems (e.g., the amphibole-bearing ones) will record the early steps of the continental extension, promoting an incipient increase of the Ti-rich amphibole in the geological record. At a late stage (ca. 50 Ma in western Pacific; Fig. 9C), further extension of the continental crust will result in the general thinning of all magmatic systems and the extensive record of mafic magma in the geological record.

Figure 8. Cumulative histograms for the occurrence of magmatic amphibole and rocks in the continental record. Magmatic amphibole and rocks from the circum-Pacific orogenic belts (CPOB) are dominant (>40%–60%) in the continental record since ca. 200 Ma.

Figure 8. Cumulative histograms for the occurrence of magmatic amphibole and rocks in the continental record. Magmatic amphibole and rocks from the circum-Pacific orogenic belts (CPOB) are dominant (>40%–60%) in the continental record since ca. 200 Ma.

The chemical evolution of magma is more linear in South America, with a progressive thickening of the accretionary belts since the Late Cretaceous, following a period of general extension and crustal thinning in the Jurassic and Early Cretaceous (Ramos and Aleman, 2000). This evolution is consistent with the magmatic history of the Central Andean orocline (Haschke et al., 2002; Mamani et al., 2010). The chemical record of magmas in South America (in general) and the Central Andean orocline (in particular) is also marked by an increasing range of composition toward SiO2-rich compositions for the youngest magmas (Fig. 11B). This evolution is consistent with the chemical record of magmatic amphiboles that evolve toward Ti-poor composition (Fig. 12B), but it differs from the Cenozoic Basin and Range record (Fig. 12A). This suggests an evolution under a compressional regime since at least the Cretaceous (Sempere et al., 2002). A significant decrease in the Dy/Yb trace element ratio in post-Oligocene (younger than 30 Ma) magma from the Central Andean orocline, indicative of amphibole sequestration in the lower crust (Davidson et al., 2007), was also observed (Mamani et al., 2010). This suggests major crustal thickening in the mid-Oligocene (Haschke et al., 2002), following an incipient crustal thickening event from ca. 90 to 30 Ma (Fig. 11C).

Implications for Plate-Tectonic Reconstructions

Based on our results, we suggest that accretionary belts in the circum-Pacific orogenic belts were subjected to progressive thickening from the Jurassic to the beginning of the Cretaceous, which involved the emplacement of progressively more differentiated magma (SiO2-rich). This thickening led to the development of “mature” deep hot zones around the Pacific, enabling magma storage and homogenization at depths up to 30–40 km (Annen et al., 2006). A major change took place from the middle of the Cretaceous to the beginning of the Eocene in western Pacific and northeastern America, associated with emplacement of less calc-alkaline and more mafic magmas during the Cenozoic (Figs. 9 and 11). This change is recognized in the chemical record of amphiboles that become Ti-rich, which is indicative of the deepest conditions of crystallization. We interpret this mineral and chemical change in the magma as resulting from the progressive thinning of the Jurassic to Cretaceous accretionary belts, which limited crustal component assimilation and amphibole filtering of the mantle-derived melts. Crustal thinning was likely driven by extensional processes, which occurred throughout the circum-Pacific orogenic belts during the final breakup of Pangea after ca. 125 Ma (Veevers, 2004). These processes were amplified by the segmentation of the Panthalassa oceanic plates during the Eocene, promoting slab rollback and inducing overriding plate extension (Schellart et al., 2010).

Figure 9. (A) Distribution of samples along the circum-Pacific orogenic belts. Map was generated using the global crustal model at 2 × 2 degrees, CRUST 2.0 (Mooney et al., 1998; Bassin et al., 2000). (B) Chemical record (Ti, apfu) of amphibole vs. time for magmatic rocks sampled along the circum-Pacific orogenic belts in the western Pacific (green area in A). The data illustrate a decreasing record of Ti-rich amphibole in the Jurassic to Middle Cretaceous Epochs, and then an increase after ca. 125 Ma. (C) Magmatic composition (SiO2 [wt%] and Th index) of all magmatic rocks sampled along the circum-Pacific orogenic belts plotted against their age. Their SiO2 composition increases (yellow curve) from ca. 175 to 75 Ma. Beyond this value, the SiO2 values decrease. Not surprisingly, the Th index record (blue curve) shows an opposite trend (anticorrelation) with decreasing values of ~1.5 from ca. 125 to ca. 75 Ma, then increasing values since 75 Ma. Remarkably, the peak in SiO2 (>63 wt%) for magmas is preceded by an increasing occurrence of Ti-rich amphiboles (part B) in the amphibole-bearing magmatic systems (green curve in C). Trias—Triassic.

Figure 9. (A) Distribution of samples along the circum-Pacific orogenic belts. Map was generated using the global crustal model at 2 × 2 degrees, CRUST 2.0 (Mooney et al., 1998; Bassin et al., 2000). (B) Chemical record (Ti, apfu) of amphibole vs. time for magmatic rocks sampled along the circum-Pacific orogenic belts in the western Pacific (green area in A). The data illustrate a decreasing record of Ti-rich amphibole in the Jurassic to Middle Cretaceous Epochs, and then an increase after ca. 125 Ma. (C) Magmatic composition (SiO2 [wt%] and Th index) of all magmatic rocks sampled along the circum-Pacific orogenic belts plotted against their age. Their SiO2 composition increases (yellow curve) from ca. 175 to 75 Ma. Beyond this value, the SiO2 values decrease. Not surprisingly, the Th index record (blue curve) shows an opposite trend (anticorrelation) with decreasing values of ~1.5 from ca. 125 to ca. 75 Ma, then increasing values since 75 Ma. Remarkably, the peak in SiO2 (>63 wt%) for magmas is preceded by an increasing occurrence of Ti-rich amphiboles (part B) in the amphibole-bearing magmatic systems (green curve in C). Trias—Triassic.

Figure 10. (A) Distribution of samples around the Cenozoic-aged Japan Sea. Map was generated using the global crustal model at 2 × 2 degrees, CRUST 2.00 (Mooney et al., 1998; Bassin et al., 2000). (B, C) Chemical evolution of amphiboles (Ti and Si, apfu) according to their ages (>500 analyses). The data were bootstrapped with an age step of 10 m.y. to highlight: (1) a dominant low-temperature and low-pressure (i.e., low-Ti and high-Si) amphibole record in Jurassic to Middle Cretaceous magmatic rocks, formed in an accretionary system merging the Japan and Eastern China blocks; and (2) an increase in high-temperature and high-pressure (i.e., high-Ti and low-Si) amphibole occurring from ca. 125 Ma to present, preceding the seafloor spreading of the Japan Sea.

Figure 10. (A) Distribution of samples around the Cenozoic-aged Japan Sea. Map was generated using the global crustal model at 2 × 2 degrees, CRUST 2.00 (Mooney et al., 1998; Bassin et al., 2000). (B, C) Chemical evolution of amphiboles (Ti and Si, apfu) according to their ages (>500 analyses). The data were bootstrapped with an age step of 10 m.y. to highlight: (1) a dominant low-temperature and low-pressure (i.e., low-Ti and high-Si) amphibole record in Jurassic to Middle Cretaceous magmatic rocks, formed in an accretionary system merging the Japan and Eastern China blocks; and (2) an increase in high-temperature and high-pressure (i.e., high-Ti and low-Si) amphibole occurring from ca. 125 Ma to present, preceding the seafloor spreading of the Japan Sea.

The spatial and temporal changes in thickening or thinning of the magmatic belts along the circum-Pacific orogenic belts, as inferred from the chemical and thermal evolution of magmas, are illustrated in Figure 13. McKenzie et al. (2015) recently suggested that most of the Pangea supercontinent was underlain by a contiguous arc of thick lithosphere. Beneath the western convex side of this arc, there was a wide belt of thinner lithosphere underlying what is believed to have been the active margin of Pangea, here named the circum-Pacific orogenic belts, or external (circum-Pacific) orogenies by Collins et al. (2011). In the Early Jurassic Epoch, oceanic crust of the Paleo-Tethys subducted under the Cimmerian plate, closing the ocean from west to east and forming internal orogenies (Collins et al., 2011). Around this period, the South China block collided with the southern margin of the North China block, producing the Qinling-Dabie orogeny (Weislogel et al., 2006), and the Lhasa terrane accreted onto Asia from the south in the Early Cretaceous (Chu et al., 2006). Active subduction and collisional processes on the eastern side of Pangea, coupled with the opening of the North Atlantic Ocean in the Middle Jurassic Epoch, likely produced progressive shortening and thickening of the belts in the western Pacific until ca. 125 Ma. At the same time, a progressive shortening of the magmatic belts took place in the eastern Pacific, thickening the northern segments of the American continent (Nevadan orogeny).

Figure 11. (A, B) Time vs. chemical evolution of magmatic rocks sampled in the eastern Pacific along the circum-Pacific orogenic belts. A polynomial curve (N = 5) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 50 or 10 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. The SiO2 content (wt%) of rocks was further matched against the Th index of the magmatic rocks (colored curves on the graphs), allowing us to identify different episodes of crustal thickening and thinning at the time of magma emplacement. In North and South America, a progressive change is observed from ca. 125 Ma to present in the chemical record of magmas that evolved toward SiO2-rich composition and become more calc-alkaline. Note that no clear evidence of crustal thinning in the Cenozoic times can be highlighted from the North America magma record with a step of 50 m.y. (C) Magmatic rocks from our database matched with the geochemical database of du Bray (2007) for igneous rocks of the north-central and northeast Nevada (from 48°N to 42°N) and Mamani et al. (2010) and Haschke et al. (2002) for igneous rocks of the Central Andean orocline (from 13°S to 18°S and 21°S to 26°S). This allows us to better highlight the late Cenozoic (ca. 30 Ma to present) crustal thickening in South America associated with a progressive chemical evolution of magma toward more SiO2-rich composition. An inverse trend was observed in North America from ca. 20 Ma to present, associated with a progressive chemical evolution of magma toward more mafic composition (Basin and Range extension). A polynomial curve (N = 5 and 2 in panels A and C, respectively) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 1 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. Trias—Triassic.

Figure 11. (A, B) Time vs. chemical evolution of magmatic rocks sampled in the eastern Pacific along the circum-Pacific orogenic belts. A polynomial curve (N = 5) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 50 or 10 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. The SiO2 content (wt%) of rocks was further matched against the Th index of the magmatic rocks (colored curves on the graphs), allowing us to identify different episodes of crustal thickening and thinning at the time of magma emplacement. In North and South America, a progressive change is observed from ca. 125 Ma to present in the chemical record of magmas that evolved toward SiO2-rich composition and become more calc-alkaline. Note that no clear evidence of crustal thinning in the Cenozoic times can be highlighted from the North America magma record with a step of 50 m.y. (C) Magmatic rocks from our database matched with the geochemical database of du Bray (2007) for igneous rocks of the north-central and northeast Nevada (from 48°N to 42°N) and Mamani et al. (2010) and Haschke et al. (2002) for igneous rocks of the Central Andean orocline (from 13°S to 18°S and 21°S to 26°S). This allows us to better highlight the late Cenozoic (ca. 30 Ma to present) crustal thickening in South America associated with a progressive chemical evolution of magma toward more SiO2-rich composition. An inverse trend was observed in North America from ca. 20 Ma to present, associated with a progressive chemical evolution of magma toward more mafic composition (Basin and Range extension). A polynomial curve (N = 5 and 2 in panels A and C, respectively) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 1 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. Trias—Triassic.

Figure 12. (A, B) Time vs. composition of amphiboles in magmatic rocks sampled in the eastern Pacific along the circum-Pacific orogenic belts (CPOB). The Si and Ti (apfu) of the amphibole (colored points within the large graphs) allow us to identify different episodes of crustal thickening and thinning at the time of magma emplacement. The tectonic context was further matched against the chemical record of amphibole, and a good correlation was observed between crustal thinning of amphibole-magmatic systems and the orogenic events that occurred in the northwestern America regions after ca. 75 Ma (Basin and Range extension). Before 75 Ma, magma records become weak, corresponding to the Sevier-Laramide orogeny that likely started ca. 85 Ma (Livaccari and Perry, 1993, and references therein), preceded by the Nevadan orogeny. The chemical evolution of magmatic amphiboles in South America follows an opposite trend, consistent with the progressive thickening of the Central Andean orocline since ca. 125 Ma (Haschke et al., 2002; Mamani et al., 2010).

Figure 12. (A, B) Time vs. composition of amphiboles in magmatic rocks sampled in the eastern Pacific along the circum-Pacific orogenic belts (CPOB). The Si and Ti (apfu) of the amphibole (colored points within the large graphs) allow us to identify different episodes of crustal thickening and thinning at the time of magma emplacement. The tectonic context was further matched against the chemical record of amphibole, and a good correlation was observed between crustal thinning of amphibole-magmatic systems and the orogenic events that occurred in the northwestern America regions after ca. 75 Ma (Basin and Range extension). Before 75 Ma, magma records become weak, corresponding to the Sevier-Laramide orogeny that likely started ca. 85 Ma (Livaccari and Perry, 1993, and references therein), preceded by the Nevadan orogeny. The chemical evolution of magmatic amphiboles in South America follows an opposite trend, consistent with the progressive thickening of the Central Andean orocline since ca. 125 Ma (Haschke et al., 2002; Mamani et al., 2010).

Figure 13. (A–B) Paleogeographic reconstructions at the time of amphibole-bearing magma emplacement, based on Jurassic to Eocene reconstructions (Veevers, 2004). The external (circum-Pacific) system consisted of a number of discrete orogens that, together, probably existed for 550 m.y. (Collins et al., 2011). Our data illustrate that a general thickening of the circum-Pacific orogenic belts accompanied the first step of Pangea breakup, the last supercontinent. Only the South American portions of the circum-Pacific orogenic belts remained unaffected by crustal thickening and experienced mostly extension in the Jurassic and Early Cretaceous. After ca. 125 m.y., a progressive thinning of the magmatic belts took place in the western Pacific and northwestern America regions, whereas shortening and thickening of the belts started in South America. (C) The chemical trends of amphiboles (Ti content) and magmas (SiO2, wt%) are remarkably consistent for each of the three domains (i.e., western Pacific, North and South America). The incipient thinning of the belts in the Cretaceous (<125 Ma) solely affected the amphibole-bearing magma systems. The chemical evolution of magma in the circum-Pacific orogenic belts started to change from calc-alkaline to tholeiitic compositions (e.g., Figs. 9 and 11) in the Cenozoic times (<60 Ma), and an increasing occurrence of Ti-rich amphibole is observed. At the same time, thickening of the belts in South America led to increasingly more calc-alkaline magma and Ti-poor amphibole production. The curves of North and South America cross around ca. 50 Ma, highlighting a period where the amphibole-bearing magmatic systems of the eastern Pacific were characterized by broadly similar thicknesses. Trias—Triassic.

Figure 13. (A–B) Paleogeographic reconstructions at the time of amphibole-bearing magma emplacement, based on Jurassic to Eocene reconstructions (Veevers, 2004). The external (circum-Pacific) system consisted of a number of discrete orogens that, together, probably existed for 550 m.y. (Collins et al., 2011). Our data illustrate that a general thickening of the circum-Pacific orogenic belts accompanied the first step of Pangea breakup, the last supercontinent. Only the South American portions of the circum-Pacific orogenic belts remained unaffected by crustal thickening and experienced mostly extension in the Jurassic and Early Cretaceous. After ca. 125 m.y., a progressive thinning of the magmatic belts took place in the western Pacific and northwestern America regions, whereas shortening and thickening of the belts started in South America. (C) The chemical trends of amphiboles (Ti content) and magmas (SiO2, wt%) are remarkably consistent for each of the three domains (i.e., western Pacific, North and South America). The incipient thinning of the belts in the Cretaceous (<125 Ma) solely affected the amphibole-bearing magma systems. The chemical evolution of magma in the circum-Pacific orogenic belts started to change from calc-alkaline to tholeiitic compositions (e.g., Figs. 9 and 11) in the Cenozoic times (<60 Ma), and an increasing occurrence of Ti-rich amphibole is observed. At the same time, thickening of the belts in South America led to increasingly more calc-alkaline magma and Ti-poor amphibole production. The curves of North and South America cross around ca. 50 Ma, highlighting a period where the amphibole-bearing magmatic systems of the eastern Pacific were characterized by broadly similar thicknesses. Trias—Triassic.

Though Pangea was still broadly intact in the beginning of the Cretaceous, it broke up after ca. 125 Ma as South America, Antarctica, and Australia rifted away from Africa, thus forming the South Atlantic and Indian Oceans. As the Atlantic Ocean widened, the convergent-margin orogenies that had begun during the Jurassic increased in the North American Cordillera, with the Nevadan orogeny, followed by the Sevier and Laramide orogenies. This period of active subduction along the circum-Pacific orogenic belts and active rifting in the core of Pangea was accompanied by a progressive thinning of the amphibole-bearing magmatic systems in the western Pacific and North America belts, whereas shortening and thickening of the belts started in South America after ca. 125 Ma.

Perspectives in Statistical Petrology: Toward an Integrated Approach

While it is increasingly accepted that statistical geochemistry can be established as a viable and powerful approach to understanding global issues in earth sciences, the robustness of geological interpretations derived from this approach remains in doubt when the secular changes are not sufficiently supported by data. A robust bootstrap analysis requires high data density and temporal continuity in the data set to ensure data representativeness (Keller and Schoene, 2012). This criticism potentially applies to this study, as our database illuminates considerable bias of sampling for magmatic amphibole and rocks in the Mesozoic record of the eastern Pacific. Hence, care must be taken when assessing the global significance of the ca. 125 Ma thermal event recorded by amphibole-bearing magmas and its consistency with the existing framework of global tectonics using a comprehensive set of independent data.

Mantle and Global Climate

The disjunction of the African and South American plates after ca. 125 Ma marked a turning point in the evolution of Pangea, which likely impacted the mantle climate evolution (Farrington et al., 2010). Determination of mantle temperature variations below continents at the time of supercontinent destruction is a fundamental issue in the discussion of global geodynamic processes; however, it remains a challenging task (Rey, 2015). Indirect clues come from the thermal signature of magmatic minerals, which provide exceptional insight into the thermal evolution of continental lithosphere through time.

In a companion paper, Ganne et al. (2016) presented the first worldwide compilation and statistical assessment of chemical information on magmatic rocks and minerals preserved in the continental record since 600 Ma, including the circum-Pacific orogenic belts. The aim of their study was to derive a global, but sufficiently representative data set of thermal constraints on magmas to highlight the process of mantle insulation below a supercontinent. Following the methods of Putirka (2008), which were built on a comprehensive review of existing thermobarometer calibrations for magmatic rocks, they compared different magmatic mineral compositions with glass (liquid) compositions using experimentally derived equations to obtain values for the temperature at the time of crystal formation.

The authors observed that the age of the thermal peak for amphiboles (ca. 275 Ma; Fig. 14C), dominantly tapping the hydrous calc-alkaline magmas forming and/or evolving at suprasubduction or crustal level, corresponds to a period of orogenic collapse for the Variscan-type belts suturing the Pangea supercontinent. Furthermore, the thermal peak for olivine (ca. 125 Ma; Fig. 14A), dominantly tapping the deep, anhydrous, and weakly evolved tholeiitic magmas, corresponds to a period of enhanced supercontinent breakup and seafloor spreading (Veevers, 2004). This is consistent with thermal peaks for clinopyroxene and plagioclase, forming in both tholeiitic and calc-alkaline magmas, which occurred at ca. 225 Ma (Fig. 14B). Ganne et al. (2016) proposed that the ~150 m.y. interval observed between thermal peaks of hotter and cooler magmatic minerals (e.g., olivine and amphibole, respectively) could be explained by the progressive thinning and thermal relaxation of the Pangea lithosphere, starting with the collapse of overthickened crustal horizons (i.e., orogenic belts) and ending with those of the lithospheric mantle at plate divergence zones.

Figure 15 summarizes this possible evolution. As the Pangea supercontinent grew in size and locally in thickness (orogenic belts), through arc-continent collision and microcontinent amalgamation, synchronous deformation and crustal reworking, with subsequent migmatite formation, enhanced mixing of magmas in the lower crust (mauve horizons in Fig. 15A). Given the protracted nature of Pangea, the progressive insulation effect due to the supercontinent must have been important, increasing the temperature of the lithospheric and asthenospheric mantle beneath the continental crust. Furthermore, this effect has been shown to be significant in the case of concurrent subduction along the boundaries of supercontinents, preventing lateral thermal mixing of the convective mantle (Lenardic et al., 2011).

During collapse and thinning of the thickened portions of the Pangea supercontinent (Fig. 15B), driven by excess gravitational potential energy and plate motion (divergence), decompression melting of the fertile crust and ambient mantle and extraction of calc-alkaline magmas (yellow trend in Fig. 15C) to more tholeiitic melts (blue and green trends) contributed to the initial thermal relaxation of the upper horizons of the lithosphere (ca. 275 Ma). This then propagated to the lowermost horizons of the lithospheric mantle in less than 150 m.y. (ca. 125 Ma).

After the breakup of the Pangea supercontinent, the subcontinental lithospheric mantle thickened through ongoing cooling and thermal subsidence, first incorporating the layer of moderately depleted mantle and then layers of unmelted fertile mantle (asthenosphere). Thermal cooling of the mantle below continents is hypothesized to have prevailed since 125 Ma, as suggested by the trend of T estimates obtained from primary magmas formed in continental settings (Ganne et al., 2016).

Figure 14. Thermal record of magmatic minerals obtained with different thermometers (Putirka, 2008; Ridolfi and Renzulli, 2012). (A, B, C) Temperature of crystallization through time of magmatic olivines (Ol), pyroxenes (Cpx—clinopyroxene), and amphiboles (Amph.) from continental settings (modified after Ganne et al., 2016). (D, E, F) Mineral sampling along the circum-Pacific orogenic belts (CPOB; western Pacific and northwestern America regions). Note the good correspondence in the general trend of temperatures. Liq.—liquid.

Figure 14. Thermal record of magmatic minerals obtained with different thermometers (Putirka, 2008; Ridolfi and Renzulli, 2012). (A, B, C) Temperature of crystallization through time of magmatic olivines (Ol), pyroxenes (Cpx—clinopyroxene), and amphiboles (Amph.) from continental settings (modified after Ganne et al., 2016). (D, E, F) Mineral sampling along the circum-Pacific orogenic belts (CPOB; western Pacific and northwestern America regions). Note the good correspondence in the general trend of temperatures. Liq.—liquid.

Circum-Pacific Orogenic Belts and Global Climate

The major tectono-magmatic trend captured by the GEOROC data set over the aggregation and dispersal of Pangea gives reasonable confidence that it is representative of exposed magmatic systems through time with minimum sampling bias (Ganne et al., 2016). Accounting for the consistency of mineral information gathered in the database, we now aim to evaluate the reliability of the mid-Cretaceous (ca. 125 Ma) event observed in the amphibole record of the circum-Pacific orogenic belts with respect to other minerals sampled in the same setting (i.e., circum-Pacific orogenic belts), like olivine and pyroxene, and to discuss its significance in the frame of Pangea supercontinent destruction.

We chose to exclude data from the South American regions because it followed a distinct evolution after 125 Ma compared to the rest of the circum-Pacific orogenic belts. The remaining data (>93% of the data set) concern the western Pacific and western regions of North America. A remarkable similarity can be observed between the thermal record of amphiboles sampled along the circum-Pacific orogenic belts, in particular, and those sampled in the continental lithosphere. Both are marked by an increase in temperature after ca. 125 Ma (Figs. 14C and 14F). This evolution differs from the olivine and pyroxene thermal records, which show decreasing temperatures of crystallization since 125 Ma (cf. Figs. 14A and 14D vs. 14B and 14E).

Figure 15. Supercontinent cycle and thermal regime. (A–B) Sketches illustrating plate dynamics during amalgamation and breakup of the Pangea supercontinent and thermal regime in the continental mantle based on the results presented in Ganne et al. (2016). After ~275 m.y., a long-lasting (~150 m.y.) thermal relaxation took place in the thickened portions of the lithosphere (i.e., orogenic belts), induced by postconvergence gravitational collapse that propagated toward the lower horizons of the lithosphere until the final breakup of Pangea. Lithosphere thinning was followed after ca. 125 m.y. by progressive cooling of the asthenospheric mantle accompanying continental drift and seafloor spreading. (C) Thermal peaks for magmatic pyroxenes and plagioclases (~225 m.y.) span a period of orogenic collapse for the belts suturing the Pangea supercontinent. Thermal peak for olivines (ca. 125 Ma) corresponds to a period of enhanced supercontinent breakup and crustal thinning of the accretionary belts surrounding the Pangea supercontinent (modified after Ganne et al., 2016).

Figure 15. Supercontinent cycle and thermal regime. (A–B) Sketches illustrating plate dynamics during amalgamation and breakup of the Pangea supercontinent and thermal regime in the continental mantle based on the results presented in Ganne et al. (2016). After ~275 m.y., a long-lasting (~150 m.y.) thermal relaxation took place in the thickened portions of the lithosphere (i.e., orogenic belts), induced by postconvergence gravitational collapse that propagated toward the lower horizons of the lithosphere until the final breakup of Pangea. Lithosphere thinning was followed after ca. 125 m.y. by progressive cooling of the asthenospheric mantle accompanying continental drift and seafloor spreading. (C) Thermal peaks for magmatic pyroxenes and plagioclases (~225 m.y.) span a period of orogenic collapse for the belts suturing the Pangea supercontinent. Thermal peak for olivines (ca. 125 Ma) corresponds to a period of enhanced supercontinent breakup and crustal thinning of the accretionary belts surrounding the Pangea supercontinent (modified after Ganne et al., 2016).

Such a difference in the thermal record of magmatic minerals can be explained by the loci of magma production in the continental lithosphere, including the circum-Pacific orogenic belts. Amphibole considered in this study formed at suprasubduction or crustal levels, dominantly along the circum-Pacific orogenic belts (>40%–50% of the data set; Fig. 8), and any changes in crustal thickness likely resulted in a change of magma and amphibole composition (Fig. 4). Therefore, the temperature increase of magmatic amphibole after ca. 125 Ma likely corresponds to a period of orogenic collapse for the accretionary belts surrounding the Pangea supercontinent (Fig. 13B). Conversely, pyroxene and olivine crystallized or evolved at higher temperatures than amphibole (averaged T < 1000 °C; Figs. 14C and 14F) in less-evolved magmas during their ascent through the mantle or crustal sections of the continental lithosphere. They dominantly record the effect of mantle and magma cooling, rather than a change in crustal thickness during accretionary belt collapse. As a whole, we emphasize that the global cooling and then warming of amphibole-bearing magmas emplaced since ca. 300 Ma along the circum-Pacific orogenic belts have been largely controlled by the disassembly and crustal reworking of the continental masses forming Pangea, related to changes in the temperature (T) and the dynamics of the subcontinental mantle.

CONCLUSIONS

Our integrated approach lends confidence to the use of geochemical and mineral correlations to qualitatively determine crustal thickness evolution in orogenic belts. However, quantitative estimates of paleocrustal thickness are far less understood petrologically and are difficult to constrain in orogenic belts that thickened over 45 km. We propose that early steps of continental extension can be distinguished in the geological record using the chemical and thermal signature of magmatic amphibole.

Using this approach, we documented the progressive buildup of a thick (>40 km) Jurassic to Cretaceous accretionary belt along the circum-Pacific orogenic belts that bounded the Panthalassa Ocean. The destruction of this thick belt started at ca. 125 Ma and was first recorded by the thinnest magmatic systems hosting amphibole-bearing magma. Thinning of the circum-Pacific orogenic belts became widespread in the northeastern regions of west America and in the western Pacific after ca. 75 Ma, possibly in response to oceanic plate segmentation and slab segmentation, which triggered slab rollback and overriding plate extension.

The robustness of our conclusions derived from data mining analysis primarily relies on the consistency of data with established constraints on the geodynamic history of the western and eastern Pacific. Accordingly, the major tectono-magmatic trend captured by our data set over the dispersal of Pangea gives reasonable confidence that it is representative of exposed magmatic systems through time with a minimum sampling bias.

Following the pioneering work of Keller and Schoene (2012), our work takes another step at demonstrating the power of data mining and analysis in the earth sciences to provide cutting-edge constraints on controversial problems that could only be answered using a global approach. Given that our results are consistent with the existing framework of global tectonics, we think that the work could serve as a proof of concept.

ACKNOWLEDGMENTS

The project was supported by l’Institut de Recherche pour le Développement (IRD) and National Institute for Earth Sciences and Astronomy–Centre National de la Recherche Scientifique (CNRS-INSU) research funds. Ganne thanks S. Demouy and M. De Saint Blanquat for providing data from North and South America that supported our conclusions. G. Wörner and M.R. Renna are warmly thanked for their stimulating reviews and for the wonderfully spirited exchange of ideas (in sometimes mutual skepticism) surrounding data interpretation. Comments by J. Blundy and P. Ridolfi on an early draft of this paper are gratefully acknowledged. Finally, we wish to thank G. Bianchini and the GSA editorial staff for their excellent editorial work.

REFERENCES CITED

Ague
,
J.J.
,
1997
,
Thermodynamic calculation of emplacement pressures for batholithic rocks, California: Implications for the aluminum-in-hornblende barometer
:
Geology
 , v.
25
, p.
563
566
, doi:.
Allen
,
J.C.
, and
Boettcher
,
A.L.
,
1983
,
The stability of amphibole in andesite and basalt at high pressures
:
American Mineralogist
 , v.
68
, p.
307
314
.
Anderson
,
J.L.
, and
Smith
,
D.R.
,
1995
,
The effects of temperature and fO2 on the Al-in-hornblende barometer
:
The American Mineralogist
 , v.
80
, p.
549
559
, doi:.
Anderson
,
J.L.
,
Barth
,
A.P.
,
Wooden
,
J.L.
, and
Mazdab
,
F.
,
2008
, Thermometers and thermobarometers in granitic systems, in
Putirka
,
K.D.
, and
Tepley
,
F.J.
, III
, eds.,
Minerals, Inclusions, and Volcanic Processes: Reviews in Mineralogy and Geochemistry
 , v.
69
, p.
121
142
, doi:.
Annen
,
C.
, and
Sparks
,
R.S.J.
,
2002
,
Effects of repetitive emplacement of basaltic intrusions on thermal evolution and melt generation in the crust
:
Earth and Planetary Science Letters
 , v.
203
, p.
937
955
, doi:.
Annen
,
C.
,
Blundy
,
J.
, and
Sparks
,
R.
,
2006
,
The genesis of intermediate and silicic magmas in deep crustal hot zones
:
Journal of Petrology
 , v.
47
, p.
505
539
, doi:.
Armstrong
,
R.L.A.
,
1988
, Mesozoic and early Cenozoic magmatic evolution of the Canadian Cordillera, in
Clark
,
S.P.
, Jr.
,
Burchfiel
,
B.C.
, and
Suppe
,
J.
, eds.,
Processes in Continental Lithospheric Deformation: Geological Society of America Special Paper 218
 , p.
55
91
, doi:.
Atherton
,
M.
, and
Petford
,
N.
,
1993
,
Generation of sodium rich magmas from newly underplated basaltic crust
:
Nature
 , v.
362
, p.
144
146
, doi:.
Bachmann
,
O.
, and
Dungan
,
M.
,
2002
,
Temperature-induced Al-zoning in hornblendes of the Fish Canyon magma, Colorado
:
Journal of Petrology
 , v.
43
, p.
1469
1503
, doi:.
Bachmann
,
O.
,
Dungan
,
M.
, and
Lipman
,
P.W.
,
2002
,
The Fish Canyon magma body, San Juan volcanic field, Colorado: Rejuvenation and eruption of an upper-crustal batholith
:
The American Mineralogist
 , v.
87
, p.
1062
1076
, doi:.
Barclay
,
J.
, and
Carmichael
,
I.S.E.
,
2004
,
A hornblende basalt from western Mexico: Water-saturated phase relations constrain a pressure-temperature window of eruptibility
:
Journal of Petrology
 , v.
45
, p.
485
506
, doi:.
Bassin
,
C.
,
Laske
,
G.
, and
Masters
,
G.
,
2000
,
The current limits of resolution for surface wave tomography in North America
:
Eos (Transactions, American Geophysical Union)
 , v.
81
,
F897
.
Blundy
,
J.
, and
Holland
,
T.J.B.
,
1990
,
Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer
:
Contributions to Mineralogy and Petrology
 , v.
104
, p.
208
224
, doi:.
Blundy
,
J.
,
Cashman
,
K.
, and
Humphrey
,
M.
,
2006
,
Magma heating by decompression-driven crystallization beneath andesite volcanoes
:
Nature
 , v.
443
, p.
76
80
, doi:.
Cawood
,
A.P.
,
Kröner
,
A.
, and
Pisarevky
,
S.
,
2006
,
Precambrian plate tectonics: Criteria and evidence
:
GSA Today
 , v.
16
, no.
7
, p.
4
11
, doi:.
Chapman
,
J.
,
Ducea
,
N.
,
DeCelles
,
P.G.
, and
Profeta
,
L.
,
2015
,
Tracking changes in crustal thickness during orogenic evolution with Sr/Y: An example from the North American Cordillera
:
Geology
 , v.
43
, p.
919
922
, doi:.
Chiaradia
,
M.
,
2014
,
Copper enrichment in arc magmas controlled by overriding plate thickness
:
Nature Geoscience
 , v.
7
, p.
43
46
, doi:.
Chu
,
M.-F.
,
Chung
,
S.L.
,
Song
,
B.
,
Liu
,
D.Y.
,
O’Reilly
,
S.Y.
,
Pearson
,
N.J.
,
Ji
,
J.Q.
, and
Wen
,
D.J.
,
2006
,
Zircon U-Pb and Hf isotope constraints on the Mesozoic tectonics and crustal evolution of southern Tibet
:
Geology
 , v.
34
, p.
745
748
, doi:.
Clemens
,
J.
,
Helps
,
P.
, and
Stevens
,
G.
,
2009
,
Chemical structure in granitic magmas—A signal from the source?
:
Earth and Environmental Science Transactions of the Royal Society of Edinburgh
 , v.
100
, p.
159
172
, doi:.
Collins
,
W.J.
,
Belousova
,
E.A.
,
Kemp
,
A.I.S.
, and
Murphy
,
J.B.
,
2011
,
Two contrasting Phanerozoic orogenic systems revealed by hafnium isotope data
:
Nature Geoscience
 , v.
4
, p.
333
337
, doi:.
Coney
,
P.J.
,
Jones
,
D.L.
, and
Monger
,
J.W.H.
,
1980
,
Cordilleran suspect terranes
:
Nature
 , v.
288
, p.
329
333
, doi:.
Coogan
,
L.A.
,
Wilson
,
R.W.
,
Gillis
,
K.M.
, and
MacLeod
,
C.J.
,
2001
,
Near-solidus evolution of oceanic gabbro: Insight from amphibole geochemistry
:
Geochimica et Cosmochimica Acta
 , v.
65
, p.
4339
4357
, doi:.
Davidson
,
J.
,
Turner
,
S.
,
Handley
,
H.
,
Macpherson
,
C.
, and
Dosseto
,
A.
,
2007
,
Amphibole “sponge” in arc crust?
:
Geology
 , v.
35
, p.
787
790
, doi:.
Davidson
,
J.
,
Turner
,
S.
, and
Plank
,
T.
,
2013
,
Dy/Dy*: Variations arising from mantle sources and petrogenetic processes
:
Journal of Petrology
 , v.
54
, p.
525
537
, doi:.
DePaolo
,
D.
,
1981
,
A neodymium and strontium isotopic study in the Mesozoic calc-alkaline granitic batholiths of the Sierra Nevada and Peninsular Ranges, California
:
Journal of Geophysical Research
 , v.
86
, p.
10,470
10,488
, doi:.
Dessimoz
,
M.
,
Müntener
,
O.
, and
Ulmer
,
P.
,
2012
,
A case for hornblende dominated fractionation of arc magmas: The Chelan Complex (Washington Cascades)
:
Contributions to Mineralogy and Petrology
 , v.
163
, p.
567
589
, doi:.
du Bray
,
E.A.
,
2007
,
Time, space, and composition relations among northern Nevada intrusive rocks and their metallogenic implications
:
Geosphere
 , v.
3
, p.
381
405
, doi:.
Ducea
,
M.
,
2001
,
The California arc: Thick granitic batholiths, eclogitic residues, lithospheric-scale thrusting, and magmatic flare-ups
:
GSA Today
 , v.
11
, no.
11
, p.
4
10
, doi:.
Dungan
,
M.A.
, and
Davidson
,
J.
,
2004
,
Partial assimilative recycling of the mafic plutonic roots of arc volcanoes: An example from the Chilean Andes
:
Geology
 , v.
32
, p.
773
776
, doi: .
Erdmann
,
S.
,
Martel
,
C.
,
Pichavant
,
M.
, and
Kushnir
,
A.
,
2014
,
Amphibole as an archivist of magmatic crystallization conditions: Problems, potential, and implications for inferring magma storage prior to the paroxysmal 2010 eruption of Mount Merapi, Indonesia
:
Contributions to Mineralogy and Petrology
 , v.
167
,
1016
, doi:.
Ernst
,
W.
,
1999
,
Hornblende, the continent maker—Evolution of H2O during circum-Pacific subduction versus continental collision
:
Geology
 , v.
27
, p.
675
678
, doi:.
Farrington
,
R.J.
,
Stegman
,
D.R.
,
Moresi
,
L.N.
,
Sandiford
,
M.
, and
May
,
D.A.
,
2010
,
Interactions of 3D mantle flow and continental lithosphere near passive margins
:
Tectonophysics
 , v.
483
, p.
20
28
, doi:.
Ganne
,
J.
,
Feng
,
X.
,
Rey
,
P.F.
, and
De Andrade
,
V.
,
2016
,
Statistical petrology reveals a link between supercontinents cycle and mantle global climate
:
The American Mineralogist
 , v.
101
, p.
2768
2773
, doi:.
Ghiorso
,
M.S.
, and
Sack
,
R.O.
,
1995
,
Chemical mass-transfer in magmatic processes IV. A revised and internally consistent thermodynamic model for the interpolation and extrapolation of liquid–solid equilibria in magmatic systems at elevated temperatures and pressures
:
Contributions to Mineralogy and Petrology
 , v.
119
, p.
197
212
, doi:.
Giesting
,
P.A.
, and
Filiberto
,
J.
,
2014
,
Quantitative models linking igneous amphibole composition with magma Cl and OH content
:
The American Mineralogist
 , v.
99
, p.
852
865
, doi:.
Glazner
,
A.
,
2007
,
Thermal limitations on incorporation of wall rock into magma
:
Geology
 , v.
35
, p.
319
322
, doi:.
Greene
,
A.R.
,
DeBari
,
S.M.
,
Kelemen
,
P.B.
,
Blusztajn
,
J.
, and
Clift
,
P.D.
,
2006
,
A detailed geochemical study of island arc crust: The Talkeetna arc section, south-central Alaska
:
Journal of Petrology
 , v.
47
, p.
1051
1093
, doi:.
Grove
,
T.L.
,
Elkins Tanton
,
L.T.
,
Parman
,
S.W.
,
Chatterjee
,
N.
,
Muentener
,
O.
, and
Gaetani
,
G.A.
,
2003
,
Fractional crystallization and mantle-melting controls on calc-alkaline differentiation trends
:
Contributions to Mineralogy and Petrology
 , v.
145
, p.
515
533
, doi:.
Hacker
,
B.R.
,
Mehl
,
L.
,
Kelemen
,
P.B.
,
Rioux
,
M.
,
Behn
,
M.D.
, and
Luffi
,
P.
,
2008
, Reconstruction of the Talkeetna intraoceanic arc of Alaska through thermobarometry:
Journal of Geophysical Research
 , v.
113
,
B03204
, doi:.
Hammarstrom
,
J.M.
,
1984
,
Microprobe Analyses of Hornblendes from 5 Calc-Alkalic Intrusive Complexes, with Data Tables for Other Calcic Amphiboles and Basic Computer Programs for Data Manipulation
:
U.S. Geological Survey Open-File Report 84-652
 ,
98
p.
Hammarstrom
,
J.M.
, and
Zen
,
E-an
,
1986
,
Aluminium in hornblende: An empirical igneous geobarometer
:
The American Mineralogist
 , v.
71
, p.
1297
1313
.
Haschke
,
M.
,
Siebel
,
W.
,
Günther
,
A.
, and
Scheuber
,
E.
,
2002
,
Repeated crustal thickening and recycling during the Andean orogeny in north Chile (21–26°S)
:
Journal of Geophysical Research–Solid Earth
 , v.
107
, p.
ECV 6-1
ECV 6-18
.
Hawthorne
,
F.C.
,
Oberti
,
R.
,
Della Ventura
,
G.
, and
Mottana
,
A.
, eds.,
2007
,
Amphiboles: Crystal, Chemistry, Occurrence, and Health Issues
:
Reviews in Mineralogy and Geochemistry
 
67
,
570
p.
Herzberg
,
C.
, and
Asimow
,
P.D.
,
2008
,
Petrology of some oceanic island basalts: PRIMELT2.XLS software for primary magma calculation
:
Geochemistry Geophysics Geosystems
 , v.
9
,
Q09001
, doi:.
Hildreth
,
W.
, and
Moorbath
,
S.
,
1988
,
Crustal contributions to arc magmatism in the Andes of central Chile
:
Contributions to Mineralogy and Petrology
 , v.
98
, p.
455
489
, doi:.
Holland
,
T.J.B.
, and
Blundy
,
J.D.
,
1994
,
Non-ideal interactions in calcic amphiboles and their bearing on amphibole-plagioclase thermometry
:
Contributions to Mineralogy and Petrology
 , v.
116
, p.
433
447
, doi:.
Hollister
,
L.S.
,
Grissom
,
G.C.
,
Peters
,
E.K.
,
Stowell
,
H.H.
, and
Sisson
,
V.B.
,
1987
,
Confirmation of the empirical correlation of Al in hornblende with pressure of solidification of calc-alkaline plutons
:
The American Mineralogist
 , v.
72
, p.
231
239
.
Humphreys
,
M.
,
Christopher
,
T.
, and
Hards
,
V.
,
2009
,
Microlite transfer by disaggregation of mafic inclusions following magma mixing at Soufriere Hills volcano, Montserrat
:
Contributions to Mineralogy and Petrology
 , v.
157
, p.
609
624
, doi:.
Janoušek
,
V.
,
Braithwaite
,
C.J.R.
,
Bowes
,
D.R.
, and
Gerdes
,
A.
,
2004
,
Magma mixing in the genesis of Hercynian calc-alkaline granitoids
:
An integrated petrographic and geochemical study of the Sazava intrusion, Central Bohemian Pluton, Czech Republic: Lithos
 , v.
78
, p.
67
99
, doi:.
Jeffcoat
,
C.R.
,
2013
,
Petrogenesis of tonalitic-trondhjemitic magmas at mid-to lower crustal depth in an arc-continent suture: A comparison of the geochronology, geobarometry, and geochemistry of the Deep Creek and Round Valley plutons, western Idaho
:
Geological Society of America Abstracts with Programs
 , v.
45
, no.
3
, p.
86
.
Johnson
,
M.C.
, and
Rutherford
,
M.J.
,
1989
,
Experimental calibration of the aluminum-in-hornblende geobarometer with application to Long Valley Caldera (California) volcanic rocks
:
Geology
 , v.
17
, p.
837
841
, doi:.
Keller
,
C.B.
, and
Schoene
,
B.
,
2012
,
Statistical geochemistry reveals disruption in secular lithospheric evolution about 2.5 Gyr ago
:
Nature
 , v.
485
, p.
490
493
, doi:.
Kent
,
A.J.R.
,
2014
, Preferential eruption of andesitic magmas: Implications for volcanic magma fluxes at convergent margins, in
Gómez-Tuena
,
A.
,
Straub
,
S.M.
, and
Zellmer
,
G.F.
, eds.,
Orogenic Andesites and Crustal Growth: Geological Society
 ,
London
,
Special Publication 385
, p.
257
280
.
Kiss
,
B.
,
Harangi
,
S.
,
Ntaflos
,
T.
,
Mason
,
P.R.D.
, and
Pal-Molnar
,
E.
,
2014
,
Amphibole perspective to unravel pre-eruptive processes and conditions in volcanic plumbing systems beneath intermediate arc volcanoes: A case study from Ciomadul volcano (SE Carpathians)
:
Contributions to Mineralogy and Petrology
 , v.
167
, p.
986
, doi:.
Kratzmann
,
D.J.
,
Carey
,
S.
,
Scasso
,
R.A.
, and
Naranjo
,
J.-A.
,
2010
,
Role of cryptic amphibole crystallization in magma differentiation at Hudson volcano, Southern Volcanic Zone, Chile
:
Contributions to Mineralogy and Petrology
 , v.
159
, p.
237
264
, doi:.
Larocque
,
J.
, and
Canil
,
D.
,
2010
,
The role of amphibole in the evolution of arc magmas and crust: The case from the Jurassic Bonanza arc section, Vancouver Island, Canada
:
Contributions to Mineralogy and Petrology
 , v.
159
, p.
475
492
, doi:.
Leake
,
B.E.
,
Woolley
,
A.R.
,
Arps
,
C.E.S.
,
Birch
,
W.D.
,
Gilbert
,
M.C.
,
Grice
,
J.D.
,
Hawthorne
,
F.C.
,
Kato
,
A.
,
Kisch
,
H.J.
,
Krivovichev
,
V.G.
,
Linthout
,
K.
,
Laird
,
J.
,
Mandarino
,
J.A.
,
Maresch
,
W.V.
,
Nickel
,
E.H.
,
Rock
,
N.M.S.
,
Schumacher
,
J.C.
,
Smith
,
D.C.
,
Stephenson
,
N.C.N.
,
Ungaretti
,
L.
,
Whittaker
,
E.J.W.
, and
Youzhi
,
G.
,
1997
,
Nomenclature of amphiboles: Report of the Subcommittee on Amphiboles of the International Mineralogical Association, Commission on New Minerals and Mineral Names
:
The American Mineralogist
 , v.
82
, p.
1019
1037
.
Lee
,
C.-T.A.
,
Lee
,
T.C.
, and
Wu
,
C.-T.
,
2014
,
Modeling the compositional evolution of recharging, evacuating, and fractionating (REFC) magma chambers: Implications for differentiation of arc magmas
:
Geochimica et Cosmochimica Acta
 , v.
143
, p.
8
22
, doi:.
Leeman
,
W.P.
,
1983
,
The influence of crustal structure on compositions of subduction-related magmas
:
Journal of Volcanology and Geothermal Research
 , v.
18
, p.
561
588
, doi: .
Lenardic
,
A.
,
Moresi
,
L.
,
Jellinek
,
A.M.
,
O’Neill
,
C.J.
,
Cooper
,
C.M.
, and
Lee
,
C.T.
,
2011
,
Continents, supercontinents, mantle thermal mixing, and mantle thermal isolation: Theory, numerical simulations, and laboratory experiments
:
Geochemistry Geophysics Geosystems
 , v.
12
,
Q10016
, doi:.
Lindsay
,
J.M.
,
Schmitt
,
A.K.
,
Trumbull
,
R.B.
,
De Silva
,
S.L.
,
Siebel
,
W.
, and
Emmermann
,
R.
,
2001
,
Magmatic evolution of the La Pacana caldera system, central Andes, Chile: Compositional variation of two cogenetic, large volume felsic ignimbrites
:
Journal of Petrology
 , v.
42
, p.
459
486
, doi:.
Livaccari
,
R.F.
, and
Perry
,
F.V.
,
1993
,
Isotopic evidence for preservation of Cordilleran lithospheric mantle during the Sevier-Laramide orogeny, western United States
:
Geology
 , v.
21
, p.
719
722
, doi:.
Mamani
,
M.
,
Wörner
,
G.
, and
Sempere
,
T.
,
2010
,
Geochemical variations in igneous rocks of the Central Andean orocline (13°S to 18°S): Tracing crustal thickening and magma generation through time and space
:
Geological Society of America Bulletin
 , v.
122
, p.
162
182
, doi:.
Manley
,
C.R.
, and
Bacon
,
C.R.
,
2000
,
Rhyolite thermobarometry and the shallowing of the magmatic reservoir, Coso volcanic field, California
:
Journal of Petrology
 , v.
41
, p.
149
174
, doi:.
Mantle
,
G.W.
, and
Collins
,
W.J.
,
2008
,
Quantifying crustal thickness variations in evolving orogens: Correlation between arc basalt composition and Moho depth
:
Geology
 , v.
36
, p.
87
90
, doi:.
McKenzie
,
D.
,
Daly
,
M.C.
, and
Priestley
,
K.
,
2015
,
The lithospheric structure of Pangea
:
Geology
 , v.
43
, p.
783
786
, doi:.
Miyashiro
,
A.
,
1974
,
Volcanic rock series in island arcs and active continental margins
:
American Journal of Science
 , v.
274
, p.
321
355
, doi:.
Mooney
,
W.D.
,
Laske
,
G.
, and
Masters
,
T.G.
,
1998
,
CRUST 5.1: A global crustal model at 5° × 5°
:
Journal of Geophysical Research
 , v.
103
, p.
727
747
, doi:.
Moulas
,
E.
,
Burg
,
J.-P.
, and
Podladchikov
,
Y
,
2014
,
Stress field associated with elliptical inclusions in a deforming matrix: Mathematical model and implications for tectonic overpressure in the lithosphere
:
Tectonophysics
 , v.
631
, p.
37
49
, doi:.
Murphy
,
J.G.
,
Foster
,
D.A.
,
Kalakay
,
T.J.
,
John
,
B.E.
, and
Hamilton
,
M.
,
2002
,
U-Pb zircon geochronology of the Eastern Pioneer igneous complex, SW Montana: Magmatism in the foreland of the Cordilleran fold and thrust belt
:
Northwest Geology
 , v.
31
, p.
1
11
.
Needy
,
S.K.
,
Anderson
,
J.L.
,
Wooden
,
J.L.
,
Fleck
,
R.J.
,
Barth
,
A.P.
,
Paterson
,
S.R.
,
Memeti
,
V.
, and
Pignotta
,
G.S.
,
2009
, Mesozoic magmatism in the upper- to middle-crustal section through the Cordilleran continental margin arc, Eastern Transverse Ranges, California, in
Miller
,
R.B.
, and
Snoke
,
A.W.
, eds.,
Crustal Cross Sections from the Western North American Cordillera and Elsewhere: Implications for Tectonic and Petrologic Processes: Geological Society of America Special Paper 456
 , p.
187
218
, doi:.
Northrup
,
C.J.
,
Royden
,
L.H.
, and
Burchfiel
,
B.C.
,
1995
,
Motion of the Pacific plate relative to Eurasia and its potential relation to Cenozoic extension along the eastern margin of Eurasia
:
Geology
 , v.
23
, p.
719
722
, doi:.
Pichavant
,
M.
,
Martel
,
C.
,
Bourdier
,
J.-L.
, and
Scaillet
,
B.
,
2002
,
Physical conditions, structure, and dynamics of a zoned magma chamber: Mount Pelée (Martinique, Lesser Antilles Arc)
:
Journal of Geophysical Research
 , v.
107
, no.
B5
, p.
ECV 1-1
ECV 1-28
, doi:.
Plank
,
T.
, and
Langmuir
,
C.H.
,
1988
,
An evaluation of the global variations in the major element chemistry of arc basalts
:
Earth and Planetary Science Letters
 , v.
90
, p.
349
370
.
Profeta
,
L.
,
Ducea
,
M.N.
,
Chapman
,
J.B.
,
Paterson
,
S.R.
,
Gonzales
,
S.M.H.
,
Kirsch
,
M.
,
Petrescu
,
L.
, and
DeCelles
,
P.G.
,
2015
,
Quantifying crustal thickness over time in magmatic arcs
:
Scientific Reports
 , v.
5
,
17786
, doi:.
Putirka
,
K.
,
2016
,
Amphibole thermometers and barometers for igneous systems, and some implications for eruption mechanisms of felsic magmas at arc volcanoes
:
The American Mineralogist
 , v.
101
, no.
4
, p.
841
858
, doi:.
Putirka
,
K.D.
,
2008
, Thermometers and barometers for volcanic systems, in
Putirka
,
K.D.
, and
Tepley
,
F.J.
, III
, eds.,
Minerals, Inclusions, and Volcanic Processes: Reviews in Mineralogy and Geochemistry
 , v.
69
, p.
61
120
.
Ramos
,
V.A.
, and
Aleman
,
A.
,
2000
, Tectonic evolution of the Andes, in
Cordani
,
U.
,
Milani
,
E.J.
,
Thomaz Filho
,
A.
, and
Campos Neto
,
M.C.
, eds.,
Tectonic Evolution of South America
 :
31st International Geological Congress
:
Rio de Janeiro
, p.
635
685
.
Ren
,
J.
,
Tamaki
,
K.
,
Li
,
S.
, and
Zhang
,
J.
,
2002
,
Late Mesozoic and Cenozoic rifting and its dynamic setting in eastern China and adjacent areas
:
Tectonophysics
 , v.
344
, p.
175
205
, doi:.
Rey
,
P.F.
,
2015
,
The geodynamics of mantle melting
:
Geology
 , v.
43
, p.
367
368
, doi:.
Ridolfi
,
F.
, and
Renzulli
,
A.
,
2012
,
Calcic amphiboles in calc-alkaline and alkaline magmas: Thermobarometric and chemometric empirical equations valid up to 1,130°C and 2.2 GPa
:
Contributions to Mineralogy and Petrology
 , v.
163
, p.
877
895
, doi:.
Rodríguez
,
C.
,
Selles
,
D.
,
Dungan
,
M.
,
Langmuir
,
C.
, and
Leeman
,
W.
,
2007
,
Adakitic dacites formed by intracrustal crystal fractionation of water-rich parent magmas at Nevado de Longavi volcano (36.2°S), Andean Southern volcanic zone, central Chile
:
Journal of Petrology
 , v.
48
, p.
2033
2061
, doi:.
Ruprecht
,
P.
, and
Bachmann
,
O.
,
2010
,
Pre-eruptive reheating during magma mixing at Quizapu volcano and the implications for the explosiveness of silicic arc volcanoes
:
Geology
 , v.
38
, p.
919
922
, doi:.
Rutherford
,
M.J.
, and
Devine
,
J.D.
,
2003
,
Magmatic conditions and magma ascent as indicated by hornblende phase equilibria and reactions in the 1995–2002 Soufrière Hills magma
:
Journal of Petrology
 , v.
44
, p.
1433
1453
, doi:.
Saleeby
,
J.B.
, and
Rubin
,
C.M.
,
2000
, U-Pb geochronology of mid-Cretaceous and Tertiary plutons along the western edge of the Coast Mountains, Revillagigedo Island, and Portland Peninsula, southeast Alaska, in
Stowell
,
H.H.
, and
McClelland
,
W.C.
, eds.,
Tectonics of the Coast Mountains, Southeastern Alaska and British Columbia: Geological Society of America Special Paper 343
 , p.
145
157
.
Samaniego
,
P.
,
Eissen
,
J.-P.
,
Le Pennec
,
J.-L.
,
Robin
,
C.
,
Hall
,
M.L.
,
Mothes
,
P.
,
Chavrit
,
D.
, and
Cotton
,
J.
,
2008
,
Pre-eruptive physical conditions of El Reventador volcano (Ecuador) inferred from the petrology of the 2002 and 2004–05 eruptions
:
Journal of Volcanology and Geothermal Research
 , v.
176
, p.
82
93
, doi:.
Schellart
,
W.P.
, and
Lister
,
G.
,
2005
,
The role of the East Asian active margin in widespread extensional and strike-slip deformation in East Asia
:
Journal of the Geological Society
 , v.
162
, p.
959
972
, doi:.
Schellart
,
W.P.
,
Lister
,
G.
, and
Toy
,
V.
,
2006
,
A Late Cretaceous and Cenozoic reconstruction of the Southwest Pacific region: Tectonics controlled by subduction and slab rollback processes
:
Earth-Science Reviews
 , v.
76
, p.
191
233
, doi:.
Schellart
,
W.P.
,
Stegman
,
D.R.
,
Farrington
,
R.J.
,
Freeman
,
J.
, and
Moresi
,
L.
,
2010
,
Cenozoic tectonics of western North America controlled by evolving width of Farallon slab
:
Science
 , v.
329
, p.
316
319
, doi:.
Schmidt
,
M.W.
,
1992
,
Amphibole composition in tonalite as a function of pressure: An experimental calibration of the Al-in-hornblende barometer
:
Contributions to Mineralogy and Petrology
 , v.
110
, p.
304
310
, doi:.
Sempere
,
T.
,
Carlier
,
G.
,
Soler
,
P.
,
Fornari
,
M.
,
Carlotto
,
V.
,
Jacay
,
J.
,
Arispe
,
O.
,
Néraudeau
,
D.
,
Cárdenas
,
J.
,
Rosas
,
S.
, and
Jiménez
,
N.
,
2002
,
Late Permian–Middle Jurassic lithospheric thinning in Peru and Bolivia, and its bearing on Andean-age tectonics
:
Tectonophysics
 , v.
345
, p.
153
181
, doi:.
Shane
,
P.
, and
Smith
,
V.C.
,
2013
,
Using amphibole crystals to reconstruct magma storage temperatures and pressures for the post-caldera collapse volcanism at Okataina volcano
:
Lithos
 , v.
156–159
, p.
159
170
, doi:.
Sigloch
,
K.
, and
Mihalymuk
,
M.G.
,
2013
,
Intra-oceanic subduction shaped the assembly of Cordilleran North America
:
Nature
 , v.
496
, p.
50
56
, doi:.
Sisson
,
T.W.
, and
Bacon
,
C.R.
,
1999
,
Gas-driven filter pressing in magmas
:
Geology
 , v.
27
, p.
613
616
, doi:.
Sisson
,
T.W.
, and
Grove
,
T.L.
,
1993
,
Experimental investigations of the role of H2O in calc-alkaline differentiation and subduction zone magmatism
:
Contributions to Mineralogy and Petrology
 , v.
113
, p.
143
166
, doi:.
Smith
,
D.J.
,
2014
,
Clinopyroxene precursors to amphibole sponge in arc crust
:
Nature Communications
 , v.
5
, p.
4329
, doi:.
Spera
,
F.
, and
Bohrson
,
W.
,
2001
,
Energy constrained open system magmatic processes: I. General model and energy-constrained assimilation and fractional crystallisation (EC-AFC) formulation
:
Journal of Petrology
 , v.
42
, p.
999
1018
, doi:.
Tajčmanová
,
L.
,
Podladchikov
,
Y.
,
Powell
,
R.
,
Moulas
,
E.
,
Vrijmoed
,
J.C.
, and
Connolly
,
J.A.D.
,
2014
,
Grain-scale pressure variations and chemical equilibrium in high-grade metamorphic rocks
:
Journal of Metamorphic Geology
 , v.
32
, p.
195
207
, doi:.
Tang
,
M.
,
Chen
,
K.
, and
Rudnick
,
R.L.
,
2016
,
Archean upper crust transition from mafic to felsic marks the onset of plate tectonics
:
Science
 , v.
351
, p.
372
375
, doi:.
Tepper
,
J.H.
,
Nelson
,
B.
,
Bergantz
,
G.
, and
Irving
,
A.
,
1993
,
Petrology of the Chilliwack batholith, North Cascades, Washington: Generation of calc-alkaline granitoids by melting of mafic lower crust with variable water fugacity
:
Contributions to Mineralogy and Petrology
 , v.
113
, p.
333
351
, doi:.
Tindle
,
A.G.
, and
Webb
,
P.C.
,
1994
,
Probe-AMPH—A spreadsheet program to classify microprobe-derived amphibole analyses
:
Computers & Geosciences
 , v.
20
, p.
1201
1228
, doi:.
Tribuzio
,
R.
,
Renna
,
M.R.
,
Dallai
,
L.
, and
Zanetti
,
A.
,
2014
,
The magmatichydrothermal transition in the lower oceanic crust: Clues from the Ligurian ophiolites, Italy
:
Geochimica et Cosmochimica Acta
 , v.
130
, p.
188
211
, doi:.
Turnbull
,
R.
,
Weaver
,
S.
,
Tulloch
,
A.
,
Cole
,
J.
,
Handler
,
M.
, and
Ireland
,
T.
,
2010
,
Field and geochemical constraints on mafic–felsic interactions, and processes in high-level arc magma chambers: An example from the Halfmoon Pluton, New Zealand
:
Journal of Petrology
 , v.
51
, p.
1477
1505
, doi:.
Turner
,
S.J.
, and
Langmuir
,
C.H.
,
2015
,
What processes control the chemical compositions of arc front stratovolcanoes?
Geochemistry Geophysics Geosystems
 , v.
16
, doi:.
Turner
,
S.
,
Caulfield
,
J.
,
Rushmer
,
T.
,
Turner
,
M.
,
Cronin
,
S.
,
Smith
,
I.
, and
Handley
,
H.
,
2012
,
Magma evolution in the primitive, intra-oceanic Tonga arc: Rapid petrogenesis of dacites at Fonualei volcano
:
Journal of Petrology
 , v.
53
, p.
1231
1253
, doi:.
van der Heyden
,
P.
,
1992
,
A Middle Jurassic to Early Tertiary Andean-Sierran arc model for the Coast belt of British Columbia
:
Tectonics
 , v.
11
, p.
82
97
, doi:.
Veevers
,
J.J.
,
2004
,
Gondwanaland from 650–500 Ma assembly through 320 Ma mergers in Pangea to 185–100 Ma breakup: Supercontinental tectonics via stratigraphy and radiometric dating
:
Earth-Science Reviews
 , v.
68
, p.
1
132
, doi:.
Wallace
,
P.J.
,
2005
,
Volatiles in subduction zone magmas: Concentrations and fluxes based on melt inclusion and volatile gas data
:
Journal of Volcanology and Geothermal Research
 , v.
140
, p.
217
240
, doi:.
Weislogel
,
A.L.
,
Graham
,
S.A.
,
Chang
,
E.Z.
,
Wooden
,
J.L.
,
Gehrels
,
G.E.
, and
Yang
,
H.
,
2006
,
Detrital zircon provenance of the Late Triassic Songpan-Ganzi complex: Sedimentary record of collision of the North and South China blocks
:
Geology
 , v.
34
, p.
97
100
, doi:.
Yoshiyuki
,
T.
,
Otofuji
,
Y.-I.
,
Matsuda
,
T.
, and
Nohda
,
S.
,
1989
,
Opening of the Sea of Japan back-arc basin by asthenospheric injection
:
Tectonophysics
 , v.
166
, p.
317
329
, doi:.
Yücel
,
C.
,
Arslan
,
M.
,
Temizel
,
I.
, and
Abdioğlu
,
E.
,
2013
,
Volcanic facies and mineral chemistry of Tertiary volcanics in the northern part of the Eastern Pontides, northeast Turkey: Implications for pre-eruptive crystallization conditions and magma chamber processes
:
Mineralogy and Petrology
 , v.
108
, p.
439
467
, doi:.
Zellmer
,
G.
,
2008
, Some first-order observations on magma transfer from mantle wedge to upper crust at volcanic arcs, in
Annen
,
C.
, and
Zellmer
,
G.
, eds.,
Dynamics of Crustal Magma Transfer, Storage, and Differentiation: Geological Society
 ,
London
,
Special Publication 304
, p.
15
31
, doi:.
Zen
,
E-an.
,
1985
,
Implications of magmatic epidote-bearing plutons on crystal evolution in the accreted terranes of northwestern North America
:
Geology
 , v.
13
, p.
266
269
, doi:.
Zhang
,
S.H.
,
Zhao
,
Y.
, and
Song
,
B.
,
2006
,
Hornblende thermobarometry of the Carboniferous granitoids from the Inner Mongolia paleouplift
:
Contributions to Mineralogy and Petrology
 , v.
87
, p.
123
141
, doi:.
1
GSA Data Repository Item 2017108, Main physico-chemical characteristics of minerals and rocks considered in this study, is available at www.geosociety.org/ datarepository/2017/, or on request from editing@geosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301-9140, USA.

Figures & Tables

Figure 1. Distribution of the magmatic calcic-amphiboles (3223 analyses) shown in classification tables (after Leake et al., 1997). Structural formulae of amphiboles were calculated using the Probe-Amph Excel program of Tindle and Webb (1994). Also shown, for each data point, are temperature (A) and pressure (B) conditions of amphibole crystallization (based on the method of Ridolfi and Renzulli, 2012).

Figure 1. Distribution of the magmatic calcic-amphiboles (3223 analyses) shown in classification tables (after Leake et al., 1997). Structural formulae of amphiboles were calculated using the Probe-Amph Excel program of Tindle and Webb (1994). Also shown, for each data point, are temperature (A) and pressure (B) conditions of amphibole crystallization (based on the method of Ridolfi and Renzulli, 2012).

Figure 2. (A) Chemical evolution (SiO2, wt%) of magmas emplaced along the circum-Pacific orogenic belts (CPOB; western and eastern Pacific) according to their age. A polynomial curve (N = 5) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 50 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. R2 corresponds to the coefficient of determination associated with the polynomial curve. (B, C) Correlation between the gradual occurrence or decrease (statistical assessment) of siliceous and tholeiitic magmas (Th index: averages of median Fe2O3 total values corresponding to the 4–6 wt% MgO interval; Chiaradia, 2014) and the crustal thickness where young Cenozoic magmatism (ca. 10–0 Ma) took place. Tholeiitic magmas dominantly developed in mafic (SiO2-poor) magma in the thinnest crustal sections (<20 km). Th index and mafic magma decrease with increasing crustal thickness, although no clear correlation (flat-lying curve, gray area on the graph) can be observed for crustal thickness ranging between ~25 and 40 km. Beyond this threshold, less confidence can be given to the bootstrapped values (green area), due to the lack of data in the geological record (see Fig. 5A). (D) Chemical evolution (Th index) of magmas emplaced along the circum-Pacific orogenic belts (western and eastern Pacific) according to their age. The data illustrate a decrease of tholeiitic magma occurrence in Jurassic to Late Cretaceous times (ca. 75 Ma). Beyond this threshold, the density of data increases (higher confidence level), along with the Th index of magmas. Trias—Triassic.

Figure 2. (A) Chemical evolution (SiO2, wt%) of magmas emplaced along the circum-Pacific orogenic belts (CPOB; western and eastern Pacific) according to their age. A polynomial curve (N = 5) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 50 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. R2 corresponds to the coefficient of determination associated with the polynomial curve. (B, C) Correlation between the gradual occurrence or decrease (statistical assessment) of siliceous and tholeiitic magmas (Th index: averages of median Fe2O3 total values corresponding to the 4–6 wt% MgO interval; Chiaradia, 2014) and the crustal thickness where young Cenozoic magmatism (ca. 10–0 Ma) took place. Tholeiitic magmas dominantly developed in mafic (SiO2-poor) magma in the thinnest crustal sections (<20 km). Th index and mafic magma decrease with increasing crustal thickness, although no clear correlation (flat-lying curve, gray area on the graph) can be observed for crustal thickness ranging between ~25 and 40 km. Beyond this threshold, less confidence can be given to the bootstrapped values (green area), due to the lack of data in the geological record (see Fig. 5A). (D) Chemical evolution (Th index) of magmas emplaced along the circum-Pacific orogenic belts (western and eastern Pacific) according to their age. The data illustrate a decrease of tholeiitic magma occurrence in Jurassic to Late Cretaceous times (ca. 75 Ma). Beyond this threshold, the density of data increases (higher confidence level), along with the Th index of magmas. Trias—Triassic.

Figure 3. Chemical record (SiO2 [wt%] and Th index) of magmatic rocks plotted against the geographic position of Cenozoic-aged samples (ca. 10–0 Ma) along the eastern parts of the circum-Pacific orogenic belts (CPOB; >6850 analyses). Mafic rocks are less abundant in Peru–north Chile magmatic systems, which were developed on a thick continental crust (60 km in the Altiplano area [A]) and more abundant along the Northern American Cordilleras (Coast Mountains [CM] and Sierra Nevada [SN]) and south Chile–Patagonia magmatic systems, where the continental crust is thinnest (<30 km). Four isodepth contours (30, 40, 45, and 50 km) are shown on the map based on the global crustal model (2 × 2 degrees) CRUST 2.0 (Mooney et al., 1998; Bassin et al., 2000).

Figure 3. Chemical record (SiO2 [wt%] and Th index) of magmatic rocks plotted against the geographic position of Cenozoic-aged samples (ca. 10–0 Ma) along the eastern parts of the circum-Pacific orogenic belts (CPOB; >6850 analyses). Mafic rocks are less abundant in Peru–north Chile magmatic systems, which were developed on a thick continental crust (60 km in the Altiplano area [A]) and more abundant along the Northern American Cordilleras (Coast Mountains [CM] and Sierra Nevada [SN]) and south Chile–Patagonia magmatic systems, where the continental crust is thinnest (<30 km). Four isodepth contours (30, 40, 45, and 50 km) are shown on the map based on the global crustal model (2 × 2 degrees) CRUST 2.0 (Mooney et al., 1998; Bassin et al., 2000).

Figure 4. (A, B) Chemical composition of amphiboles plotted against the thickness of the crust (Mooney et al., 1998) where young Cenozoic magmas (ca. 10–0 Ma), hosting these amphiboles, were emplaced (>3000 analyses, 141 bibliographic references). Ti-rich (>0.25 apfu) and Si-depleted (<6 apfu) magmatic amphiboles dominantly developed in mafic (SiO2-poor, <55 wt%: blue point) magma in the thinnest crustal sections. Si-depleted and Ti-rich record of amphiboles and mafic magma decreases with increasing crustal thickness. Ti-poor (<0.2 apfu; see Fig. 4B) and Si-rich (>6.2 apfu; see Fig. 4A) magmatic amphiboles dominantly developed in felsic (SiO2-rich >65 wt%; see Fig. 4A) magma in the thickest crustal sections. A polynomial curve (N = 4–6) fitting the bootstrapped values (1000 draws, threshold value of 3, crust step of 5 km, uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. R2 corresponds to the coefficient of determination associated with the polynomial curve. (C) The control of crustal thickness on magma composition was also investigated by statistical analysis (gray points on the graph correspond to analyses from magmas hosting amphiboles; 446 points). It shows that the thicker the (arc) crust, the less mafic is the bulk-rock chemistry. (D, E) Temperature (T) and pressure (P) conditions of amphibole crystallization using the RR2012 (Ridolfi and Renzulli, 2012) method. It confirms that the number of moderate-(>5 kbar) to high-P (>8 kbar) and high-T (> 950–1000 °C) amphiboles decreases with crustal thickening.

Figure 4. (A, B) Chemical composition of amphiboles plotted against the thickness of the crust (Mooney et al., 1998) where young Cenozoic magmas (ca. 10–0 Ma), hosting these amphiboles, were emplaced (>3000 analyses, 141 bibliographic references). Ti-rich (>0.25 apfu) and Si-depleted (<6 apfu) magmatic amphiboles dominantly developed in mafic (SiO2-poor, <55 wt%: blue point) magma in the thinnest crustal sections. Si-depleted and Ti-rich record of amphiboles and mafic magma decreases with increasing crustal thickness. Ti-poor (<0.2 apfu; see Fig. 4B) and Si-rich (>6.2 apfu; see Fig. 4A) magmatic amphiboles dominantly developed in felsic (SiO2-rich >65 wt%; see Fig. 4A) magma in the thickest crustal sections. A polynomial curve (N = 4–6) fitting the bootstrapped values (1000 draws, threshold value of 3, crust step of 5 km, uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. R2 corresponds to the coefficient of determination associated with the polynomial curve. (C) The control of crustal thickness on magma composition was also investigated by statistical analysis (gray points on the graph correspond to analyses from magmas hosting amphiboles; 446 points). It shows that the thicker the (arc) crust, the less mafic is the bulk-rock chemistry. (D, E) Temperature (T) and pressure (P) conditions of amphibole crystallization using the RR2012 (Ridolfi and Renzulli, 2012) method. It confirms that the number of moderate-(>5 kbar) to high-P (>8 kbar) and high-T (> 950–1000 °C) amphiboles decreases with crustal thickening.

Figure 5. Pressure and temperature conditions of amphibole crystallization, calculated with the RR2012 (Ridolfi and Renzulli, 2012) method, plotted against their chemical composition (3223 analyses). (A) Ti (apfu) content in amphibole showing the dominant control of temperature on the Ti-tschermak substitution. (B) Si (apfu) content in amphibole showing the dominant control of pressure on the Al-tschermak substitution. The data suggest that high-Ti and low-Si amphiboles are stable at higher temperature and pressure conditions.

Figure 5. Pressure and temperature conditions of amphibole crystallization, calculated with the RR2012 (Ridolfi and Renzulli, 2012) method, plotted against their chemical composition (3223 analyses). (A) Ti (apfu) content in amphibole showing the dominant control of temperature on the Ti-tschermak substitution. (B) Si (apfu) content in amphibole showing the dominant control of pressure on the Al-tschermak substitution. The data suggest that high-Ti and low-Si amphiboles are stable at higher temperature and pressure conditions.

Figure 6. Statistical analysis to explore the variability of temperature (T) and pressure (P) conditions of amphibole (3223 analyses) crystallization vs. their chemical composition (Ti and Si apfu). T and P conditions, calculated with the RR2012 (Ridolfi and Renzulli, 2012) method, were bootstrapped (resampling method: 1000 draws, threshold value of 3, step of 10 °C and 10 bars, respectively). Temperature (A, B), and to a lesser extent pressure (D, E), seem to exert a first-order control on the Ti and Si composition of magmatic amphibole. The data suggest that high-Ti (>0.25 apfu) and low-Si (<6 apfu) amphiboles are stable at temperature and pressure above 950 °C and 5 kbar, respectively (blue point). Low-Ti (<0.2 apfu) and high-Si (>6.2 apfu) amphiboles are stable at temperature and pressure lower than 900 °C and 3 kbar, respectively. (C) Chemical composition (Ti apfu content) of amphiboles according to their bulk-rock composition (SiO2, wt%). A negative correlation (statistical assessment) with the Si content of the magmatic rock is observed.

Figure 6. Statistical analysis to explore the variability of temperature (T) and pressure (P) conditions of amphibole (3223 analyses) crystallization vs. their chemical composition (Ti and Si apfu). T and P conditions, calculated with the RR2012 (Ridolfi and Renzulli, 2012) method, were bootstrapped (resampling method: 1000 draws, threshold value of 3, step of 10 °C and 10 bars, respectively). Temperature (A, B), and to a lesser extent pressure (D, E), seem to exert a first-order control on the Ti and Si composition of magmatic amphibole. The data suggest that high-Ti (>0.25 apfu) and low-Si (<6 apfu) amphiboles are stable at temperature and pressure above 950 °C and 5 kbar, respectively (blue point). Low-Ti (<0.2 apfu) and high-Si (>6.2 apfu) amphiboles are stable at temperature and pressure lower than 900 °C and 3 kbar, respectively. (C) Chemical composition (Ti apfu content) of amphiboles according to their bulk-rock composition (SiO2, wt%). A negative correlation (statistical assessment) with the Si content of the magmatic rock is observed.

Figure 7. (A) Chemical composition of magmas (light-gray points) plotted against crustal thickness (Mooney et al., 1998) where young Cenozoic magmas (ca. 10–0 Ma) were emplaced (>19,000 analyses). The amphibole-bearing magma record is given by the dark-gray points. Data illustrate that amphibole-bearing magmatic systems developed in a large range of crustal thicknesses (<10–60 km), forming magmas with more SiO2-rich composition (red curve) compared to the average magma record (black curve). (B, C) Comparative distribution of crustal thickness where Cenozoic-aged (ca. 10–0 Ma) magmatic rocks have been sampled. (D) Schematic three-dimensional model of active margin undergoing overriding plate extension. It is expected that the thinnest magmatic systems (e.g., the amphibole-bearing ones) will record the early steps of the continental extension, promoting an incipient increase of the Ti-rich amphibole in the geological record. At a late stage (ca. 50 Ma in western Pacific; Fig. 9C), further extension of the continental crust will result in the general thinning of all magmatic systems and the extensive record of mafic magma in the geological record.

Figure 7. (A) Chemical composition of magmas (light-gray points) plotted against crustal thickness (Mooney et al., 1998) where young Cenozoic magmas (ca. 10–0 Ma) were emplaced (>19,000 analyses). The amphibole-bearing magma record is given by the dark-gray points. Data illustrate that amphibole-bearing magmatic systems developed in a large range of crustal thicknesses (<10–60 km), forming magmas with more SiO2-rich composition (red curve) compared to the average magma record (black curve). (B, C) Comparative distribution of crustal thickness where Cenozoic-aged (ca. 10–0 Ma) magmatic rocks have been sampled. (D) Schematic three-dimensional model of active margin undergoing overriding plate extension. It is expected that the thinnest magmatic systems (e.g., the amphibole-bearing ones) will record the early steps of the continental extension, promoting an incipient increase of the Ti-rich amphibole in the geological record. At a late stage (ca. 50 Ma in western Pacific; Fig. 9C), further extension of the continental crust will result in the general thinning of all magmatic systems and the extensive record of mafic magma in the geological record.

Figure 8. Cumulative histograms for the occurrence of magmatic amphibole and rocks in the continental record. Magmatic amphibole and rocks from the circum-Pacific orogenic belts (CPOB) are dominant (>40%–60%) in the continental record since ca. 200 Ma.

Figure 8. Cumulative histograms for the occurrence of magmatic amphibole and rocks in the continental record. Magmatic amphibole and rocks from the circum-Pacific orogenic belts (CPOB) are dominant (>40%–60%) in the continental record since ca. 200 Ma.

Figure 9. (A) Distribution of samples along the circum-Pacific orogenic belts. Map was generated using the global crustal model at 2 × 2 degrees, CRUST 2.0 (Mooney et al., 1998; Bassin et al., 2000). (B) Chemical record (Ti, apfu) of amphibole vs. time for magmatic rocks sampled along the circum-Pacific orogenic belts in the western Pacific (green area in A). The data illustrate a decreasing record of Ti-rich amphibole in the Jurassic to Middle Cretaceous Epochs, and then an increase after ca. 125 Ma. (C) Magmatic composition (SiO2 [wt%] and Th index) of all magmatic rocks sampled along the circum-Pacific orogenic belts plotted against their age. Their SiO2 composition increases (yellow curve) from ca. 175 to 75 Ma. Beyond this value, the SiO2 values decrease. Not surprisingly, the Th index record (blue curve) shows an opposite trend (anticorrelation) with decreasing values of ~1.5 from ca. 125 to ca. 75 Ma, then increasing values since 75 Ma. Remarkably, the peak in SiO2 (>63 wt%) for magmas is preceded by an increasing occurrence of Ti-rich amphiboles (part B) in the amphibole-bearing magmatic systems (green curve in C). Trias—Triassic.

Figure 9. (A) Distribution of samples along the circum-Pacific orogenic belts. Map was generated using the global crustal model at 2 × 2 degrees, CRUST 2.0 (Mooney et al., 1998; Bassin et al., 2000). (B) Chemical record (Ti, apfu) of amphibole vs. time for magmatic rocks sampled along the circum-Pacific orogenic belts in the western Pacific (green area in A). The data illustrate a decreasing record of Ti-rich amphibole in the Jurassic to Middle Cretaceous Epochs, and then an increase after ca. 125 Ma. (C) Magmatic composition (SiO2 [wt%] and Th index) of all magmatic rocks sampled along the circum-Pacific orogenic belts plotted against their age. Their SiO2 composition increases (yellow curve) from ca. 175 to 75 Ma. Beyond this value, the SiO2 values decrease. Not surprisingly, the Th index record (blue curve) shows an opposite trend (anticorrelation) with decreasing values of ~1.5 from ca. 125 to ca. 75 Ma, then increasing values since 75 Ma. Remarkably, the peak in SiO2 (>63 wt%) for magmas is preceded by an increasing occurrence of Ti-rich amphiboles (part B) in the amphibole-bearing magmatic systems (green curve in C). Trias—Triassic.

Figure 10. (A) Distribution of samples around the Cenozoic-aged Japan Sea. Map was generated using the global crustal model at 2 × 2 degrees, CRUST 2.00 (Mooney et al., 1998; Bassin et al., 2000). (B, C) Chemical evolution of amphiboles (Ti and Si, apfu) according to their ages (>500 analyses). The data were bootstrapped with an age step of 10 m.y. to highlight: (1) a dominant low-temperature and low-pressure (i.e., low-Ti and high-Si) amphibole record in Jurassic to Middle Cretaceous magmatic rocks, formed in an accretionary system merging the Japan and Eastern China blocks; and (2) an increase in high-temperature and high-pressure (i.e., high-Ti and low-Si) amphibole occurring from ca. 125 Ma to present, preceding the seafloor spreading of the Japan Sea.

Figure 10. (A) Distribution of samples around the Cenozoic-aged Japan Sea. Map was generated using the global crustal model at 2 × 2 degrees, CRUST 2.00 (Mooney et al., 1998; Bassin et al., 2000). (B, C) Chemical evolution of amphiboles (Ti and Si, apfu) according to their ages (>500 analyses). The data were bootstrapped with an age step of 10 m.y. to highlight: (1) a dominant low-temperature and low-pressure (i.e., low-Ti and high-Si) amphibole record in Jurassic to Middle Cretaceous magmatic rocks, formed in an accretionary system merging the Japan and Eastern China blocks; and (2) an increase in high-temperature and high-pressure (i.e., high-Ti and low-Si) amphibole occurring from ca. 125 Ma to present, preceding the seafloor spreading of the Japan Sea.

Figure 11. (A, B) Time vs. chemical evolution of magmatic rocks sampled in the eastern Pacific along the circum-Pacific orogenic belts. A polynomial curve (N = 5) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 50 or 10 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. The SiO2 content (wt%) of rocks was further matched against the Th index of the magmatic rocks (colored curves on the graphs), allowing us to identify different episodes of crustal thickening and thinning at the time of magma emplacement. In North and South America, a progressive change is observed from ca. 125 Ma to present in the chemical record of magmas that evolved toward SiO2-rich composition and become more calc-alkaline. Note that no clear evidence of crustal thinning in the Cenozoic times can be highlighted from the North America magma record with a step of 50 m.y. (C) Magmatic rocks from our database matched with the geochemical database of du Bray (2007) for igneous rocks of the north-central and northeast Nevada (from 48°N to 42°N) and Mamani et al. (2010) and Haschke et al. (2002) for igneous rocks of the Central Andean orocline (from 13°S to 18°S and 21°S to 26°S). This allows us to better highlight the late Cenozoic (ca. 30 Ma to present) crustal thickening in South America associated with a progressive chemical evolution of magma toward more SiO2-rich composition. An inverse trend was observed in North America from ca. 20 Ma to present, associated with a progressive chemical evolution of magma toward more mafic composition (Basin and Range extension). A polynomial curve (N = 5 and 2 in panels A and C, respectively) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 1 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. Trias—Triassic.

Figure 11. (A, B) Time vs. chemical evolution of magmatic rocks sampled in the eastern Pacific along the circum-Pacific orogenic belts. A polynomial curve (N = 5) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 50 or 10 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. The SiO2 content (wt%) of rocks was further matched against the Th index of the magmatic rocks (colored curves on the graphs), allowing us to identify different episodes of crustal thickening and thinning at the time of magma emplacement. In North and South America, a progressive change is observed from ca. 125 Ma to present in the chemical record of magmas that evolved toward SiO2-rich composition and become more calc-alkaline. Note that no clear evidence of crustal thinning in the Cenozoic times can be highlighted from the North America magma record with a step of 50 m.y. (C) Magmatic rocks from our database matched with the geochemical database of du Bray (2007) for igneous rocks of the north-central and northeast Nevada (from 48°N to 42°N) and Mamani et al. (2010) and Haschke et al. (2002) for igneous rocks of the Central Andean orocline (from 13°S to 18°S and 21°S to 26°S). This allows us to better highlight the late Cenozoic (ca. 30 Ma to present) crustal thickening in South America associated with a progressive chemical evolution of magma toward more SiO2-rich composition. An inverse trend was observed in North America from ca. 20 Ma to present, associated with a progressive chemical evolution of magma toward more mafic composition (Basin and Range extension). A polynomial curve (N = 5 and 2 in panels A and C, respectively) fitting the bootstrapped values (1000 draws, threshold value of 3, age step of 1 m.y., uncertainty bars corresponding to ±1σ standard deviation) is reported on the graphs. Trias—Triassic.

Figure 12. (A, B) Time vs. composition of amphiboles in magmatic rocks sampled in the eastern Pacific along the circum-Pacific orogenic belts (CPOB). The Si and Ti (apfu) of the amphibole (colored points within the large graphs) allow us to identify different episodes of crustal thickening and thinning at the time of magma emplacement. The tectonic context was further matched against the chemical record of amphibole, and a good correlation was observed between crustal thinning of amphibole-magmatic systems and the orogenic events that occurred in the northwestern America regions after ca. 75 Ma (Basin and Range extension). Before 75 Ma, magma records become weak, corresponding to the Sevier-Laramide orogeny that likely started ca. 85 Ma (Livaccari and Perry, 1993, and references therein), preceded by the Nevadan orogeny. The chemical evolution of magmatic amphiboles in South America follows an opposite trend, consistent with the progressive thickening of the Central Andean orocline since ca. 125 Ma (Haschke et al., 2002; Mamani et al., 2010).

Figure 12. (A, B) Time vs. composition of amphiboles in magmatic rocks sampled in the eastern Pacific along the circum-Pacific orogenic belts (CPOB). The Si and Ti (apfu) of the amphibole (colored points within the large graphs) allow us to identify different episodes of crustal thickening and thinning at the time of magma emplacement. The tectonic context was further matched against the chemical record of amphibole, and a good correlation was observed between crustal thinning of amphibole-magmatic systems and the orogenic events that occurred in the northwestern America regions after ca. 75 Ma (Basin and Range extension). Before 75 Ma, magma records become weak, corresponding to the Sevier-Laramide orogeny that likely started ca. 85 Ma (Livaccari and Perry, 1993, and references therein), preceded by the Nevadan orogeny. The chemical evolution of magmatic amphiboles in South America follows an opposite trend, consistent with the progressive thickening of the Central Andean orocline since ca. 125 Ma (Haschke et al., 2002; Mamani et al., 2010).

Figure 13. (A–B) Paleogeographic reconstructions at the time of amphibole-bearing magma emplacement, based on Jurassic to Eocene reconstructions (Veevers, 2004). The external (circum-Pacific) system consisted of a number of discrete orogens that, together, probably existed for 550 m.y. (Collins et al., 2011). Our data illustrate that a general thickening of the circum-Pacific orogenic belts accompanied the first step of Pangea breakup, the last supercontinent. Only the South American portions of the circum-Pacific orogenic belts remained unaffected by crustal thickening and experienced mostly extension in the Jurassic and Early Cretaceous. After ca. 125 m.y., a progressive thinning of the magmatic belts took place in the western Pacific and northwestern America regions, whereas shortening and thickening of the belts started in South America. (C) The chemical trends of amphiboles (Ti content) and magmas (SiO2, wt%) are remarkably consistent for each of the three domains (i.e., western Pacific, North and South America). The incipient thinning of the belts in the Cretaceous (<125 Ma) solely affected the amphibole-bearing magma systems. The chemical evolution of magma in the circum-Pacific orogenic belts started to change from calc-alkaline to tholeiitic compositions (e.g., Figs. 9 and 11) in the Cenozoic times (<60 Ma), and an increasing occurrence of Ti-rich amphibole is observed. At the same time, thickening of the belts in South America led to increasingly more calc-alkaline magma and Ti-poor amphibole production. The curves of North and South America cross around ca. 50 Ma, highlighting a period where the amphibole-bearing magmatic systems of the eastern Pacific were characterized by broadly similar thicknesses. Trias—Triassic.

Figure 13. (A–B) Paleogeographic reconstructions at the time of amphibole-bearing magma emplacement, based on Jurassic to Eocene reconstructions (Veevers, 2004). The external (circum-Pacific) system consisted of a number of discrete orogens that, together, probably existed for 550 m.y. (Collins et al., 2011). Our data illustrate that a general thickening of the circum-Pacific orogenic belts accompanied the first step of Pangea breakup, the last supercontinent. Only the South American portions of the circum-Pacific orogenic belts remained unaffected by crustal thickening and experienced mostly extension in the Jurassic and Early Cretaceous. After ca. 125 m.y., a progressive thinning of the magmatic belts took place in the western Pacific and northwestern America regions, whereas shortening and thickening of the belts started in South America. (C) The chemical trends of amphiboles (Ti content) and magmas (SiO2, wt%) are remarkably consistent for each of the three domains (i.e., western Pacific, North and South America). The incipient thinning of the belts in the Cretaceous (<125 Ma) solely affected the amphibole-bearing magma systems. The chemical evolution of magma in the circum-Pacific orogenic belts started to change from calc-alkaline to tholeiitic compositions (e.g., Figs. 9 and 11) in the Cenozoic times (<60 Ma), and an increasing occurrence of Ti-rich amphibole is observed. At the same time, thickening of the belts in South America led to increasingly more calc-alkaline magma and Ti-poor amphibole production. The curves of North and South America cross around ca. 50 Ma, highlighting a period where the amphibole-bearing magmatic systems of the eastern Pacific were characterized by broadly similar thicknesses. Trias—Triassic.

Figure 14. Thermal record of magmatic minerals obtained with different thermometers (Putirka, 2008; Ridolfi and Renzulli, 2012). (A, B, C) Temperature of crystallization through time of magmatic olivines (Ol), pyroxenes (Cpx—clinopyroxene), and amphiboles (Amph.) from continental settings (modified after Ganne et al., 2016). (D, E, F) Mineral sampling along the circum-Pacific orogenic belts (CPOB; western Pacific and northwestern America regions). Note the good correspondence in the general trend of temperatures. Liq.—liquid.

Figure 14. Thermal record of magmatic minerals obtained with different thermometers (Putirka, 2008; Ridolfi and Renzulli, 2012). (A, B, C) Temperature of crystallization through time of magmatic olivines (Ol), pyroxenes (Cpx—clinopyroxene), and amphiboles (Amph.) from continental settings (modified after Ganne et al., 2016). (D, E, F) Mineral sampling along the circum-Pacific orogenic belts (CPOB; western Pacific and northwestern America regions). Note the good correspondence in the general trend of temperatures. Liq.—liquid.

Figure 15. Supercontinent cycle and thermal regime. (A–B) Sketches illustrating plate dynamics during amalgamation and breakup of the Pangea supercontinent and thermal regime in the continental mantle based on the results presented in Ganne et al. (2016). After ~275 m.y., a long-lasting (~150 m.y.) thermal relaxation took place in the thickened portions of the lithosphere (i.e., orogenic belts), induced by postconvergence gravitational collapse that propagated toward the lower horizons of the lithosphere until the final breakup of Pangea. Lithosphere thinning was followed after ca. 125 m.y. by progressive cooling of the asthenospheric mantle accompanying continental drift and seafloor spreading. (C) Thermal peaks for magmatic pyroxenes and plagioclases (~225 m.y.) span a period of orogenic collapse for the belts suturing the Pangea supercontinent. Thermal peak for olivines (ca. 125 Ma) corresponds to a period of enhanced supercontinent breakup and crustal thinning of the accretionary belts surrounding the Pangea supercontinent (modified after Ganne et al., 2016).

Figure 15. Supercontinent cycle and thermal regime. (A–B) Sketches illustrating plate dynamics during amalgamation and breakup of the Pangea supercontinent and thermal regime in the continental mantle based on the results presented in Ganne et al. (2016). After ~275 m.y., a long-lasting (~150 m.y.) thermal relaxation took place in the thickened portions of the lithosphere (i.e., orogenic belts), induced by postconvergence gravitational collapse that propagated toward the lower horizons of the lithosphere until the final breakup of Pangea. Lithosphere thinning was followed after ca. 125 m.y. by progressive cooling of the asthenospheric mantle accompanying continental drift and seafloor spreading. (C) Thermal peaks for magmatic pyroxenes and plagioclases (~225 m.y.) span a period of orogenic collapse for the belts suturing the Pangea supercontinent. Thermal peak for olivines (ca. 125 Ma) corresponds to a period of enhanced supercontinent breakup and crustal thinning of the accretionary belts surrounding the Pangea supercontinent (modified after Ganne et al., 2016).

Contents

References

REFERENCES CITED

Ague
,
J.J.
,
1997
,
Thermodynamic calculation of emplacement pressures for batholithic rocks, California: Implications for the aluminum-in-hornblende barometer
:
Geology
 , v.
25
, p.
563
566
, doi:.
Allen
,
J.C.
, and
Boettcher
,
A.L.
,
1983
,
The stability of amphibole in andesite and basalt at high pressures
:
American Mineralogist
 , v.
68
, p.
307
314
.
Anderson
,
J.L.
, and
Smith
,
D.R.
,
1995
,
The effects of temperature and fO2 on the Al-in-hornblende barometer
:
The American Mineralogist
 , v.
80
, p.
549
559
, doi:.
Anderson
,
J.L.
,
Barth
,
A.P.
,
Wooden
,
J.L.
, and
Mazdab
,
F.
,
2008
, Thermometers and thermobarometers in granitic systems, in
Putirka
,
K.D.
, and
Tepley
,
F.J.
, III
, eds.,
Minerals, Inclusions, and Volcanic Processes: Reviews in Mineralogy and Geochemistry
 , v.
69
, p.
121
142
, doi:.
Annen
,
C.
, and
Sparks
,
R.S.J.
,
2002
,
Effects of repetitive emplacement of basaltic intrusions on thermal evolution and melt generation in the crust
:
Earth and Planetary Science Letters
 , v.
203
, p.
937
955
, doi:.
Annen
,
C.
,
Blundy
,
J.
, and
Sparks
,
R.
,
2006
,
The genesis of intermediate and silicic magmas in deep crustal hot zones
:
Journal of Petrology
 , v.
47
, p.
505
539
, doi:.
Armstrong
,
R.L.A.
,
1988
, Mesozoic and early Cenozoic magmatic evolution of the Canadian Cordillera, in
Clark
,
S.P.
, Jr.
,
Burchfiel
,
B.C.
, and
Suppe
,
J.
, eds.,
Processes in Continental Lithospheric Deformation: Geological Society of America Special Paper 218
 , p.
55
91
, doi:.
Atherton
,
M.
, and
Petford
,
N.
,
1993
,
Generation of sodium rich magmas from newly underplated basaltic crust
:
Nature
 , v.
362
, p.
144
146
, doi:.
Bachmann
,
O.
, and
Dungan
,
M.
,
2002
,
Temperature-induced Al-zoning in hornblendes of the Fish Canyon magma, Colorado
:
Journal of Petrology
 , v.
43
, p.
1469
1503
, doi:.
Bachmann
,
O.
,
Dungan
,
M.
, and
Lipman
,
P.W.
,
2002
,
The Fish Canyon magma body, San Juan volcanic field, Colorado: Rejuvenation and eruption of an upper-crustal batholith
:
The American Mineralogist
 , v.
87
, p.
1062
1076
, doi:.
Barclay
,
J.
, and
Carmichael
,
I.S.E.
,
2004
,
A hornblende basalt from western Mexico: Water-saturated phase relations constrain a pressure-temperature window of eruptibility
:
Journal of Petrology
 , v.
45
, p.
485
506
, doi:.
Bassin
,
C.
,
Laske
,
G.
, and
Masters
,
G.
,
2000
,
The current limits of resolution for surface wave tomography in North America
:
Eos (Transactions, American Geophysical Union)
 , v.
81
,
F897
.
Blundy
,
J.
, and
Holland
,
T.J.B.
,
1990
,
Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer
:
Contributions to Mineralogy and Petrology
 , v.
104
, p.
208
224
, doi:.
Blundy
,
J.
,
Cashman
,
K.
, and
Humphrey
,
M.
,
2006
,
Magma heating by decompression-driven crystallization beneath andesite volcanoes
:
Nature
 , v.
443
, p.
76
80
, doi:.
Cawood
,
A.P.
,
Kröner
,
A.
, and
Pisarevky
,
S.
,
2006
,
Precambrian plate tectonics: Criteria and evidence
:
GSA Today
 , v.
16
, no.
7
, p.
4
11
, doi:.
Chapman
,
J.
,
Ducea
,
N.
,
DeCelles
,
P.G.
, and
Profeta
,
L.
,
2015
,
Tracking changes in crustal thickness during orogenic evolution with Sr/Y: An example from the North American Cordillera
:
Geology
 , v.
43
, p.
919
922
, doi:.
Chiaradia
,
M.
,
2014
,
Copper enrichment in arc magmas controlled by overriding plate thickness
:
Nature Geoscience
 , v.
7
, p.
43
46
, doi:.
Chu
,
M.-F.
,
Chung
,
S.L.
,
Song
,
B.
,
Liu
,
D.Y.
,
O’Reilly
,
S.Y.
,
Pearson
,
N.J.
,
Ji
,
J.Q.
, and
Wen
,
D.J.
,
2006
,
Zircon U-Pb and Hf isotope constraints on the Mesozoic tectonics and crustal evolution of southern Tibet
:
Geology
 , v.
34
, p.
745
748
, doi:.
Clemens
,
J.
,
Helps
,
P.
, and
Stevens
,
G.
,
2009
,
Chemical structure in granitic magmas—A signal from the source?
:
Earth and Environmental Science Transactions of the Royal Society of Edinburgh
 , v.
100
, p.
159
172
, doi:.
Collins
,
W.J.
,
Belousova
,
E.A.
,
Kemp
,
A.I.S.
, and
Murphy
,
J.B.
,
2011
,
Two contrasting Phanerozoic orogenic systems revealed by hafnium isotope data
:
Nature Geoscience
 , v.
4
, p.
333
337
, doi:.
Coney
,
P.J.
,
Jones
,
D.L.
, and
Monger
,
J.W.H.
,
1980
,
Cordilleran suspect terranes
:
Nature
 , v.
288
, p.
329
333
, doi:.
Coogan
,
L.A.
,
Wilson
,
R.W.
,
Gillis
,
K.M.
, and
MacLeod
,
C.J.
,
2001
,
Near-solidus evolution of oceanic gabbro: Insight from amphibole geochemistry
:
Geochimica et Cosmochimica Acta
 , v.
65
, p.
4339
4357
, doi:.
Davidson
,
J.
,
Turner
,
S.
,
Handley
,
H.
,
Macpherson
,
C.
, and
Dosseto
,
A.
,
2007
,
Amphibole “sponge” in arc crust?
:
Geology
 , v.
35
, p.
787
790
, doi:.
Davidson
,
J.
,
Turner
,
S.
, and
Plank
,
T.
,
2013
,
Dy/Dy*: Variations arising from mantle sources and petrogenetic processes
:
Journal of Petrology
 , v.
54
, p.
525
537
, doi:.
DePaolo
,
D.
,
1981
,
A neodymium and strontium isotopic study in the Mesozoic calc-alkaline granitic batholiths of the Sierra Nevada and Peninsular Ranges, California
:
Journal of Geophysical Research
 , v.
86
, p.
10,470
10,488
, doi:.
Dessimoz
,
M.
,
Müntener
,
O.
, and
Ulmer
,
P.
,
2012
,
A case for hornblende dominated fractionation of arc magmas: The Chelan Complex (Washington Cascades)
:
Contributions to Mineralogy and Petrology
 , v.
163
, p.
567
589
, doi:.
du Bray
,
E.A.
,
2007
,
Time, space, and composition relations among northern Nevada intrusive rocks and their metallogenic implications
:
Geosphere
 , v.
3
, p.
381
405
, doi:.
Ducea
,
M.
,
2001
,
The California arc: Thick granitic batholiths, eclogitic residues, lithospheric-scale thrusting, and magmatic flare-ups
:
GSA Today
 , v.
11
, no.
11
, p.
4
10
, doi:.
Dungan
,
M.A.
, and
Davidson
,
J.
,
2004
,
Partial assimilative recycling of the mafic plutonic roots of arc volcanoes: An example from the Chilean Andes
:
Geology
 , v.
32
, p.
773
776
, doi: .
Erdmann
,
S.
,
Martel
,
C.
,
Pichavant
,
M.
, and
Kushnir
,
A.
,
2014
,
Amphibole as an archivist of magmatic crystallization conditions: Problems, potential, and implications for inferring magma storage prior to the paroxysmal 2010 eruption of Mount Merapi, Indonesia
:
Contributions to Mineralogy and Petrology
 , v.
167
,
1016
, doi:.
Ernst
,
W.
,
1999
,
Hornblende, the continent maker—Evolution of H2O during circum-Pacific subduction versus continental collision
:
Geology
 , v.
27
, p.
675
678
, doi:.
Farrington
,
R.J.
,
Stegman
,
D.R.
,
Moresi
,
L.N.
,
Sandiford
,
M.
, and
May
,
D.A.
,
2010
,
Interactions of 3D mantle flow and continental lithosphere near passive margins
:
Tectonophysics
 , v.
483
, p.
20
28
, doi:.
Ganne
,
J.
,
Feng
,
X.
,
Rey
,
P.F.
, and
De Andrade
,
V.
,
2016
,
Statistical petrology reveals a link between supercontinents cycle and mantle global climate
:
The American Mineralogist
 , v.
101
, p.
2768
2773
, doi:.
Ghiorso
,
M.S.
, and
Sack
,
R.O.
,
1995
,
Chemical mass-transfer in magmatic processes IV. A revised and internally consistent thermodynamic model for the interpolation and extrapolation of liquid–solid equilibria in magmatic systems at elevated temperatures and pressures
:
Contributions to Mineralogy and Petrology
 , v.
119
, p.
197
212
, doi:.
Giesting
,
P.A.
, and
Filiberto
,
J.
,
2014
,
Quantitative models linking igneous amphibole composition with magma Cl and OH content
:
The American Mineralogist
 , v.
99
, p.
852
865
, doi:.
Glazner
,
A.
,
2007
,
Thermal limitations on incorporation of wall rock into magma
:
Geology
 , v.
35
, p.
319
322
, doi:.
Greene
,
A.R.
,
DeBari
,
S.M.
,
Kelemen
,
P.B.
,
Blusztajn
,
J.
, and
Clift
,
P.D.
,
2006
,
A detailed geochemical study of island arc crust: The Talkeetna arc section, south-central Alaska
:
Journal of Petrology
 , v.
47
, p.
1051
1093
, doi:.
Grove
,
T.L.
,
Elkins Tanton
,
L.T.
,
Parman
,
S.W.
,
Chatterjee
,
N.
,
Muentener
,
O.
, and
Gaetani
,
G.A.
,
2003
,
Fractional crystallization and mantle-melting controls on calc-alkaline differentiation trends
:
Contributions to Mineralogy and Petrology
 , v.
145
, p.
515
533
, doi:.
Hacker
,
B.R.
,
Mehl
,
L.
,
Kelemen
,
P.B.
,
Rioux
,
M.
,
Behn
,
M.D.
, and
Luffi
,
P.
,
2008
, Reconstruction of the Talkeetna intraoceanic arc of Alaska through thermobarometry:
Journal of Geophysical Research
 , v.
113
,
B03204
, doi:.
Hammarstrom
,
J.M.
,
1984
,
Microprobe Analyses of Hornblendes from 5 Calc-Alkalic Intrusive Complexes, with Data Tables for Other Calcic Amphiboles and Basic Computer Programs for Data Manipulation
:
U.S. Geological Survey Open-File Report 84-652
 ,
98
p.
Hammarstrom
,
J.M.
, and
Zen
,
E-an
,
1986
,
Aluminium in hornblende: An empirical igneous geobarometer
:
The American Mineralogist
 , v.
71
, p.
1297
1313
.
Haschke
,
M.
,
Siebel
,
W.
,
Günther
,
A.
, and
Scheuber
,
E.
,
2002
,
Repeated crustal thickening and recycling during the Andean orogeny in north Chile (21–26°S)
:
Journal of Geophysical Research–Solid Earth
 , v.
107
, p.
ECV 6-1
ECV 6-18
.
Hawthorne
,
F.C.
,
Oberti
,
R.
,
Della Ventura
,
G.
, and
Mottana
,
A.
, eds.,
2007
,
Amphiboles: Crystal, Chemistry, Occurrence, and Health Issues
:
Reviews in Mineralogy and Geochemistry
 
67
,
570
p.
Herzberg
,
C.
, and
Asimow
,
P.D.
,
2008
,
Petrology of some oceanic island basalts: PRIMELT2.XLS software for primary magma calculation
:
Geochemistry Geophysics Geosystems
 , v.
9
,
Q09001
, doi:.
Hildreth
,
W.
, and
Moorbath
,
S.
,
1988
,
Crustal contributions to arc magmatism in the Andes of central Chile
:
Contributions to Mineralogy and Petrology
 , v.
98
, p.
455
489
, doi:.
Holland
,
T.J.B.
, and
Blundy
,
J.D.
,
1994
,
Non-ideal interactions in calcic amphiboles and their bearing on amphibole-plagioclase thermometry
:
Contributions to Mineralogy and Petrology
 , v.
116
, p.
433
447
, doi:.
Hollister
,
L.S.
,
Grissom
,
G.C.
,
Peters
,
E.K.
,
Stowell
,
H.H.
, and
Sisson
,
V.B.
,
1987
,
Confirmation of the empirical correlation of Al in hornblende with pressure of solidification of calc-alkaline plutons
:
The American Mineralogist
 , v.
72
, p.
231
239
.
Humphreys
,
M.
,
Christopher
,
T.
, and
Hards
,
V.
,
2009
,
Microlite transfer by disaggregation of mafic inclusions following magma mixing at Soufriere Hills volcano, Montserrat
:
Contributions to Mineralogy and Petrology
 , v.
157
, p.
609
624
, doi:.
Janoušek
,
V.
,
Braithwaite
,
C.J.R.
,
Bowes
,
D.R.
, and
Gerdes
,
A.
,
2004
,
Magma mixing in the genesis of Hercynian calc-alkaline granitoids
:
An integrated petrographic and geochemical study of the Sazava intrusion, Central Bohemian Pluton, Czech Republic: Lithos
 , v.
78
, p.
67
99
, doi:.
Jeffcoat
,
C.R.
,
2013
,
Petrogenesis of tonalitic-trondhjemitic magmas at mid-to lower crustal depth in an arc-continent suture: A comparison of the geochronology, geobarometry, and geochemistry of the Deep Creek and Round Valley plutons, western Idaho
:
Geological Society of America Abstracts with Programs
 , v.
45
, no.
3
, p.
86
.
Johnson
,
M.C.
, and
Rutherford
,
M.J.
,
1989
,
Experimental calibration of the aluminum-in-hornblende geobarometer with application to Long Valley Caldera (California) volcanic rocks
:
Geology
 , v.
17
, p.
837
841
, doi:.
Keller
,
C.B.
, and
Schoene
,
B.
,
2012
,
Statistical geochemistry reveals disruption in secular lithospheric evolution about 2.5 Gyr ago
:
Nature
 , v.
485
, p.
490
493
, doi:.
Kent
,
A.J.R.
,
2014
, Preferential eruption of andesitic magmas: Implications for volcanic magma fluxes at convergent margins, in
Gómez-Tuena
,
A.
,
Straub
,
S.M.
, and
Zellmer
,
G.F.
, eds.,
Orogenic Andesites and Crustal Growth: Geological Society
 ,
London
,
Special Publication 385
, p.
257
280
.
Kiss
,
B.
,
Harangi
,
S.
,
Ntaflos
,
T.
,
Mason
,
P.R.D.
, and
Pal-Molnar
,
E.
,
2014
,
Amphibole perspective to unravel pre-eruptive processes and conditions in volcanic plumbing systems beneath intermediate arc volcanoes: A case study from Ciomadul volcano (SE Carpathians)
:
Contributions to Mineralogy and Petrology
 , v.
167
, p.
986
, doi:.
Kratzmann
,
D.J.
,
Carey
,
S.
,
Scasso
,
R.A.
, and
Naranjo
,
J.-A.
,
2010
,
Role of cryptic amphibole crystallization in magma differentiation at Hudson volcano, Southern Volcanic Zone, Chile
:
Contributions to Mineralogy and Petrology
 , v.
159
, p.
237
264
, doi:.
Larocque
,
J.
, and
Canil
,
D.
,
2010
,
The role of amphibole in the evolution of arc magmas and crust: The case from the Jurassic Bonanza arc section, Vancouver Island, Canada
:
Contributions to Mineralogy and Petrology
 , v.
159
, p.
475
492
, doi:.
Leake
,
B.E.
,
Woolley
,
A.R.
,
Arps
,
C.E.S.
,
Birch
,
W.D.
,
Gilbert
,
M.C.
,
Grice
,
J.D.
,
Hawthorne
,
F.C.
,
Kato
,
A.
,
Kisch
,
H.J.
,
Krivovichev
,
V.G.
,
Linthout
,
K.
,
Laird
,
J.
,
Mandarino
,
J.A.
,
Maresch
,
W.V.
,
Nickel
,
E.H.
,
Rock
,
N.M.S.
,
Schumacher
,
J.C.
,
Smith
,
D.C.
,
Stephenson
,
N.C.N.
,
Ungaretti
,
L.
,
Whittaker
,
E.J.W.
, and
Youzhi
,
G.
,
1997
,
Nomenclature of amphiboles: Report of the Subcommittee on Amphiboles of the International Mineralogical Association, Commission on New Minerals and Mineral Names
:
The American Mineralogist
 , v.
82
, p.
1019
1037
.
Lee
,
C.-T.A.
,
Lee
,
T.C.
, and
Wu
,
C.-T.
,
2014
,
Modeling the compositional evolution of recharging, evacuating, and fractionating (REFC) magma chambers: Implications for differentiation of arc magmas
:
Geochimica et Cosmochimica Acta
 , v.
143
, p.
8
22
, doi:.
Leeman
,
W.P.
,
1983
,
The influence of crustal structure on compositions of subduction-related magmas
:
Journal of Volcanology and Geothermal Research
 , v.
18
, p.
561
588
, doi: .
Lenardic
,
A.
,
Moresi
,
L.
,
Jellinek
,
A.M.
,
O’Neill
,
C.J.
,
Cooper
,
C.M.
, and
Lee
,
C.T.
,
2011
,
Continents, supercontinents, mantle thermal mixing, and mantle thermal isolation: Theory, numerical simulations, and laboratory experiments
:
Geochemistry Geophysics Geosystems
 , v.
12
,
Q10016
, doi:.
Lindsay
,
J.M.
,
Schmitt
,
A.K.
,
Trumbull
,
R.B.
,
De Silva
,
S.L.
,
Siebel
,
W.
, and
Emmermann
,
R.
,
2001
,
Magmatic evolution of the La Pacana caldera system, central Andes, Chile: Compositional variation of two cogenetic, large volume felsic ignimbrites
:
Journal of Petrology
 , v.
42
, p.
459
486
, doi:.
Livaccari
,
R.F.
, and
Perry
,
F.V.
,
1993
,
Isotopic evidence for preservation of Cordilleran lithospheric mantle during the Sevier-Laramide orogeny, western United States
:
Geology
 , v.
21
, p.
719
722
, doi:.
Mamani
,
M.
,
Wörner
,
G.
, and
Sempere
,
T.
,
2010
,
Geochemical variations in igneous rocks of the Central Andean orocline (13°S to 18°S): Tracing crustal thickening and magma generation through time and space
:
Geological Society of America Bulletin
 , v.
122
, p.
162
182
, doi:.
Manley
,
C.R.
, and
Bacon
,
C.R.
,
2000
,
Rhyolite thermobarometry and the shallowing of the magmatic reservoir, Coso volcanic field, California
:
Journal of Petrology
 , v.
41
, p.
149
174
, doi:.
Mantle
,
G.W.
, and
Collins
,
W.J.
,
2008
,
Quantifying crustal thickness variations in evolving orogens: Correlation between arc basalt composition and Moho depth
:
Geology
 , v.
36
, p.
87
90
, doi:.
McKenzie
,
D.
,
Daly
,
M.C.
, and
Priestley
,
K.
,
2015
,
The lithospheric structure of Pangea
:
Geology
 , v.
43
, p.
783
786
, doi:.
Miyashiro
,
A.
,
1974
,
Volcanic rock series in island arcs and active continental margins
:
American Journal of Science
 , v.
274
, p.
321
355
, doi:.
Mooney
,
W.D.
,
Laske
,
G.
, and
Masters
,
T.G.
,
1998
,
CRUST 5.1: A global crustal model at 5° × 5°
:
Journal of Geophysical Research
 , v.
103
, p.
727
747
, doi:.
Moulas
,
E.
,
Burg
,
J.-P.
, and
Podladchikov
,
Y
,
2014
,
Stress field associated with elliptical inclusions in a deforming matrix: Mathematical model and implications for tectonic overpressure in the lithosphere
:
Tectonophysics
 , v.
631
, p.
37
49
, doi:.
Murphy
,
J.G.
,
Foster
,
D.A.
,
Kalakay
,
T.J.
,
John
,
B.E.
, and
Hamilton
,
M.
,
2002
,
U-Pb zircon geochronology of the Eastern Pioneer igneous complex, SW Montana: Magmatism in the foreland of the Cordilleran fold and thrust belt
:
Northwest Geology
 , v.
31
, p.
1
11
.
Needy
,
S.K.
,
Anderson
,
J.L.
,
Wooden
,
J.L.
,
Fleck
,
R.J.
,
Barth
,
A.P.
,
Paterson
,
S.R.
,
Memeti
,
V.
, and
Pignotta
,
G.S.
,
2009
, Mesozoic magmatism in the upper- to middle-crustal section through the Cordilleran continental margin arc, Eastern Transverse Ranges, California, in
Miller
,
R.B.
, and
Snoke
,
A.W.
, eds.,
Crustal Cross Sections from the Western North American Cordillera and Elsewhere: Implications for Tectonic and Petrologic Processes: Geological Society of America Special Paper 456
 , p.
187
218
, doi:.
Northrup
,
C.J.
,
Royden
,
L.H.
, and
Burchfiel
,
B.C.
,
1995
,
Motion of the Pacific plate relative to Eurasia and its potential relation to Cenozoic extension along the eastern margin of Eurasia
:
Geology
 , v.
23
, p.
719
722
, doi:.
Pichavant
,
M.
,
Martel
,
C.
,
Bourdier
,
J.-L.
, and
Scaillet
,
B.
,
2002
,
Physical conditions, structure, and dynamics of a zoned magma chamber: Mount Pelée (Martinique, Lesser Antilles Arc)
:
Journal of Geophysical Research
 , v.
107
, no.
B5
, p.
ECV 1-1
ECV 1-28
, doi:.
Plank
,
T.
, and
Langmuir
,
C.H.
,
1988
,
An evaluation of the global variations in the major element chemistry of arc basalts
:
Earth and Planetary Science Letters
 , v.
90
, p.
349
370
.
Profeta
,
L.
,
Ducea
,
M.N.
,
Chapman
,
J.B.
,
Paterson
,
S.R.
,
Gonzales
,
S.M.H.
,
Kirsch
,
M.
,
Petrescu
,
L.
, and
DeCelles
,
P.G.
,
2015
,
Quantifying crustal thickness over time in magmatic arcs
:
Scientific Reports
 , v.
5
,
17786
, doi:.
Putirka
,
K.
,
2016
,
Amphibole thermometers and barometers for igneous systems, and some implications for eruption mechanisms of felsic magmas at arc volcanoes
:
The American Mineralogist
 , v.
101
, no.
4
, p.
841
858
, doi:.
Putirka
,
K.D.
,
2008
, Thermometers and barometers for volcanic systems, in
Putirka
,
K.D.
, and
Tepley
,
F.J.
, III
, eds.,
Minerals, Inclusions, and Volcanic Processes: Reviews in Mineralogy and Geochemistry
 , v.
69
, p.
61
120
.
Ramos
,
V.A.
, and
Aleman
,
A.
,
2000
, Tectonic evolution of the Andes, in
Cordani
,
U.
,
Milani
,
E.J.
,
Thomaz Filho
,
A.
, and
Campos Neto
,
M.C.
, eds.,
Tectonic Evolution of South America
 :
31st International Geological Congress
:
Rio de Janeiro
, p.
635
685
.
Ren
,
J.
,
Tamaki
,
K.
,
Li
,
S.
, and
Zhang
,
J.
,
2002
,
Late Mesozoic and Cenozoic rifting and its dynamic setting in eastern China and adjacent areas
:
Tectonophysics
 , v.
344
, p.
175
205
, doi:.
Rey
,
P.F.
,
2015
,
The geodynamics of mantle melting
:
Geology
 , v.
43
, p.
367
368
, doi:.
Ridolfi
,
F.
, and
Renzulli
,
A.
,
2012
,
Calcic amphiboles in calc-alkaline and alkaline magmas: Thermobarometric and chemometric empirical equations valid up to 1,130°C and 2.2 GPa
:
Contributions to Mineralogy and Petrology
 , v.
163
, p.
877
895
, doi:.
Rodríguez
,
C.
,
Selles
,
D.
,
Dungan
,
M.
,
Langmuir
,
C.
, and
Leeman
,
W.
,
2007
,
Adakitic dacites formed by intracrustal crystal fractionation of water-rich parent magmas at Nevado de Longavi volcano (36.2°S), Andean Southern volcanic zone, central Chile
:
Journal of Petrology
 , v.
48
, p.
2033
2061
, doi:.
Ruprecht
,
P.
, and
Bachmann
,
O.
,
2010
,
Pre-eruptive reheating during magma mixing at Quizapu volcano and the implications for the explosiveness of silicic arc volcanoes
:
Geology
 , v.
38
, p.
919
922
, doi:.
Rutherford
,
M.J.
, and
Devine
,
J.D.
,
2003
,
Magmatic conditions and magma ascent as indicated by hornblende phase equilibria and reactions in the 1995–2002 Soufrière Hills magma
:
Journal of Petrology
 , v.
44
, p.
1433
1453
, doi:.
Saleeby
,
J.B.
, and
Rubin
,
C.M.
,
2000
, U-Pb geochronology of mid-Cretaceous and Tertiary plutons along the western edge of the Coast Mountains, Revillagigedo Island, and Portland Peninsula, southeast Alaska, in
Stowell
,
H.H.
, and
McClelland
,
W.C.
, eds.,
Tectonics of the Coast Mountains, Southeastern Alaska and British Columbia: Geological Society of America Special Paper 343
 , p.
145
157
.
Samaniego
,
P.
,
Eissen
,
J.-P.
,
Le Pennec
,
J.-L.
,
Robin
,
C.
,
Hall
,
M.L.
,
Mothes
,
P.
,
Chavrit
,
D.
, and
Cotton
,
J.
,
2008
,
Pre-eruptive physical conditions of El Reventador volcano (Ecuador) inferred from the petrology of the 2002 and 2004–05 eruptions
:
Journal of Volcanology and Geothermal Research
 , v.
176
, p.
82
93
, doi:.
Schellart
,
W.P.
, and
Lister
,
G.
,
2005
,
The role of the East Asian active margin in widespread extensional and strike-slip deformation in East Asia
:
Journal of the Geological Society
 , v.
162
, p.
959
972
, doi:.
Schellart
,
W.P.
,
Lister
,
G.
, and
Toy
,
V.
,
2006
,
A Late Cretaceous and Cenozoic reconstruction of the Southwest Pacific region: Tectonics controlled by subduction and slab rollback processes
:
Earth-Science Reviews
 , v.
76
, p.
191
233
, doi:.
Schellart
,
W.P.
,
Stegman
,
D.R.
,
Farrington
,
R.J.
,
Freeman
,
J.
, and
Moresi
,
L.
,
2010
,
Cenozoic tectonics of western North America controlled by evolving width of Farallon slab
:
Science
 , v.
329
, p.
316
319
, doi:.
Schmidt
,
M.W.
,
1992
,
Amphibole composition in tonalite as a function of pressure: An experimental calibration of the Al-in-hornblende barometer
:
Contributions to Mineralogy and Petrology
 , v.
110
, p.
304
310
, doi:.
Sempere
,
T.
,
Carlier
,
G.
,
Soler
,
P.
,
Fornari
,
M.
,
Carlotto
,
V.
,
Jacay
,
J.
,
Arispe
,
O.
,
Néraudeau
,
D.
,
Cárdenas
,
J.
,
Rosas
,
S.
, and
Jiménez
,
N.
,
2002
,
Late Permian–Middle Jurassic lithospheric thinning in Peru and Bolivia, and its bearing on Andean-age tectonics
:
Tectonophysics
 , v.
345
, p.
153
181
, doi:.
Shane
,
P.
, and
Smith
,
V.C.
,
2013
,
Using amphibole crystals to reconstruct magma storage temperatures and pressures for the post-caldera collapse volcanism at Okataina volcano
:
Lithos
 , v.
156–159
, p.
159
170
, doi:.
Sigloch
,
K.
, and
Mihalymuk
,
M.G.
,
2013
,
Intra-oceanic subduction shaped the assembly of Cordilleran North America
:
Nature
 , v.
496
, p.
50
56
, doi:.
Sisson
,
T.W.
, and
Bacon
,
C.R.
,
1999
,
Gas-driven filter pressing in magmas
:
Geology
 , v.
27
, p.
613
616
, doi:.
Sisson
,
T.W.
, and
Grove
,
T.L.
,
1993
,
Experimental investigations of the role of H2O in calc-alkaline differentiation and subduction zone magmatism
:
Contributions to Mineralogy and Petrology
 , v.
113
, p.
143
166
, doi:.
Smith
,
D.J.
,
2014
,
Clinopyroxene precursors to amphibole sponge in arc crust
:
Nature Communications
 , v.
5
, p.
4329
, doi:.
Spera
,
F.
, and
Bohrson
,
W.
,
2001
,
Energy constrained open system magmatic processes: I. General model and energy-constrained assimilation and fractional crystallisation (EC-AFC) formulation
:
Journal of Petrology
 , v.
42
, p.
999
1018
, doi:.
Tajčmanová
,
L.
,
Podladchikov
,
Y.
,
Powell
,
R.
,
Moulas
,
E.
,
Vrijmoed
,
J.C.
, and
Connolly
,
J.A.D.
,
2014
,
Grain-scale pressure variations and chemical equilibrium in high-grade metamorphic rocks
:
Journal of Metamorphic Geology
 , v.
32
, p.
195
207
, doi:.
Tang
,
M.
,
Chen
,
K.
, and
Rudnick
,
R.L.
,
2016
,
Archean upper crust transition from mafic to felsic marks the onset of plate tectonics
:
Science
 , v.
351
, p.
372
375
, doi:.
Tepper
,
J.H.
,
Nelson
,
B.
,
Bergantz
,
G.
, and
Irving
,
A.
,
1993
,
Petrology of the Chilliwack batholith, North Cascades, Washington: Generation of calc-alkaline granitoids by melting of mafic lower crust with variable water fugacity
:
Contributions to Mineralogy and Petrology
 , v.
113
, p.
333
351
, doi:.
Tindle
,
A.G.
, and
Webb
,
P.C.
,
1994
,
Probe-AMPH—A spreadsheet program to classify microprobe-derived amphibole analyses
:
Computers & Geosciences
 , v.
20
, p.
1201
1228
, doi:.
Tribuzio
,
R.
,
Renna
,
M.R.
,
Dallai
,
L.
, and
Zanetti
,
A.
,
2014
,
The magmatichydrothermal transition in the lower oceanic crust: Clues from the Ligurian ophiolites, Italy
:
Geochimica et Cosmochimica Acta
 , v.
130
, p.
188
211
, doi:.
Turnbull
,
R.
,
Weaver
,
S.
,
Tulloch
,
A.
,
Cole
,
J.
,
Handler
,
M.
, and
Ireland
,
T.
,
2010
,
Field and geochemical constraints on mafic–felsic interactions, and processes in high-level arc magma chambers: An example from the Halfmoon Pluton, New Zealand
:
Journal of Petrology
 , v.
51
, p.
1477
1505
, doi:.
Turner
,
S.J.
, and
Langmuir
,
C.H.
,
2015
,
What processes control the chemical compositions of arc front stratovolcanoes?
Geochemistry Geophysics Geosystems
 , v.
16
, doi:.
Turner
,
S.
,
Caulfield
,
J.
,
Rushmer
,
T.
,
Turner
,
M.
,
Cronin
,
S.
,
Smith
,
I.
, and
Handley
,
H.
,
2012
,
Magma evolution in the primitive, intra-oceanic Tonga arc: Rapid petrogenesis of dacites at Fonualei volcano
:
Journal of Petrology
 , v.
53
, p.
1231
1253
, doi:.
van der Heyden
,
P.
,
1992
,
A Middle Jurassic to Early Tertiary Andean-Sierran arc model for the Coast belt of British Columbia
:
Tectonics
 , v.
11
, p.
82
97
, doi:.
Veevers
,
J.J.
,
2004
,
Gondwanaland from 650–500 Ma assembly through 320 Ma mergers in Pangea to 185–100 Ma breakup: Supercontinental tectonics via stratigraphy and radiometric dating
:
Earth-Science Reviews
 , v.
68
, p.
1
132
, doi:.
Wallace
,
P.J.
,
2005
,
Volatiles in subduction zone magmas: Concentrations and fluxes based on melt inclusion and volatile gas data
:
Journal of Volcanology and Geothermal Research
 , v.
140
, p.
217
240
, doi:.
Weislogel
,
A.L.
,
Graham
,
S.A.
,
Chang
,
E.Z.
,
Wooden
,
J.L.
,
Gehrels
,
G.E.
, and
Yang
,
H.
,
2006
,
Detrital zircon provenance of the Late Triassic Songpan-Ganzi complex: Sedimentary record of collision of the North and South China blocks
:
Geology
 , v.
34
, p.
97
100
, doi:.
Yoshiyuki
,
T.
,
Otofuji
,
Y.-I.
,
Matsuda
,
T.
, and
Nohda
,
S.
,
1989
,
Opening of the Sea of Japan back-arc basin by asthenospheric injection
:
Tectonophysics
 , v.
166
, p.
317
329
, doi:.
Yücel
,
C.
,
Arslan
,
M.
,
Temizel
,
I.
, and
Abdioğlu
,
E.
,
2013
,
Volcanic facies and mineral chemistry of Tertiary volcanics in the northern part of the Eastern Pontides, northeast Turkey: Implications for pre-eruptive crystallization conditions and magma chamber processes
:
Mineralogy and Petrology
 , v.
108
, p.
439
467
, doi:.
Zellmer
,
G.
,
2008
, Some first-order observations on magma transfer from mantle wedge to upper crust at volcanic arcs, in
Annen
,
C.
, and
Zellmer
,
G.
, eds.,
Dynamics of Crustal Magma Transfer, Storage, and Differentiation: Geological Society
 ,
London
,
Special Publication 304
, p.
15
31
, doi:.
Zen
,
E-an.
,
1985
,
Implications of magmatic epidote-bearing plutons on crystal evolution in the accreted terranes of northwestern North America
:
Geology
 , v.
13
, p.
266
269
, doi:.
Zhang
,
S.H.
,
Zhao
,
Y.
, and
Song
,
B.
,
2006
,
Hornblende thermobarometry of the Carboniferous granitoids from the Inner Mongolia paleouplift
:
Contributions to Mineralogy and Petrology
 , v.
87
, p.
123
141
, doi:.

Related

Citing Books via

Related Articles
Related Book Content
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal