We studied two short, high-gradient river systems draining the Dolomite Alps in northeastern Italy in order to determine which grain types survive transport and to what extent sand grain types reflect source rocks. Grains of all the labile rock types in the source areas survived to lower reaches of the rivers. In one drainage (Boite-Piave), they reached the Adriatic coast. Carbonate grains (largely dolomite) in the Gadera-Rienza Rivers decreased abruptly, largely by dilution, from >50% to trace amounts in 100 km of travel. Percentage of carbonate grains in the lower reaches of these rivers was generally less than one-half the areal percentage of limestone and dolostone exposure in the source areas. However, in the Boite-Piave Rivers (200 km long), enrichment of carbonate grains in beach sand at the expense of polycrystalline quartz and volcanic rock fragments results in dolostone sand at the beach reflecting 78% of its outcrop abundance and limestone (calcite) sand reflecting 68% of its outcrop abundance. Polycrystalline quartz and mafic volcanic rock fragments are less abundant in the beach because of dilution by longshore drift or the breakdown of these grains by wave abrasion. The relative resistance of carbonate textural grain types to abrasion is micrite > spar > mixed micrite/spar. The results indicate that detritus from dominantly silicic and intermediate volcanic rocks can survive fluvial transport and at least moderate wave abrasion. Metamorphic rock fragments (mostly phyllite) in the Gadera-Rienza Rivers survived transport to the confluence with the Isarco River at Bressanone. In the Boite-Piave river system, metamorphic rock fragments survived fluvial transport to the beach plus some beach abrasion. They did so because the relatively rapid transport down the high-gradient, low-sinuosity streams did not permit extensive chemical weathering. Grains of calcite (micrite and spar), dolomite, and volcanic rock fragments increased in roundness by abrasion in the surf after undergoing only a few kilometers of transport along the coast.

A cyclic vertical succession of alluvial, littoral, and shallow-marine deposits is identified within two continuously cored boreholes (187-S1 and 204-S15) drilled to ∼180 m beneath the present Po coastal plain, in northern Italy. Integrated sedimentologic, micropaleontologic (benthic foraminifers and ostracods), and geochemical studies allow the reconstruction of the paleogeographic evolution of the study area during the late Quaternary, with a special emphasis on major changes in provenance and sediment dispersal patterns. Transgressive surfaces appear as the most readily identifiable stratigraphic features in the two cores, allowing identification of a series of transgressive-regressive sequences. The transgressive surfaces mark the onset of coastal to shallow-marine conditions, followed by delta and strand plain progradation and the reestablishment of continental environments. This cyclic pattern of facies is paralleled by distinctive cyclic variations in chemical composition of sediments, reflecting a systematic increase in Ni/Al within lower transgressive deposits, followed by a marked decrease in the overlying alluvial plain sediments. At relatively northern locations (core 187-S1), the maximum flooding surfaces identified within shallow-marine deposits on the basis of subtle, but consistent changes in microfaunal assemblages are characterized by anomalously high Mg/Al values. The abrupt peaks in Ni/Al recorded at the transgressive surfaces are interpreted to reflect enrichments in mafic-ultramafic detritus, probably derived from the western Alps and the northwestern Apennines and supplied by the Po River to the coastal areas. These variations took place at the onset of brackish and littoral conditions, when direct connection with the sea favored sediment dispersal from the Po River mouth to lagoonal and coastal environments via the littoral drift. High Mg/Al values within open-marine deposits at the maximum flooding surfaces likely reflect an increasing contribution from eastern Alpine (dolomite-rich) sources at time of maximum shoreline migration. The recurrent changes in geochemical composition recorded across the transgressive surfaces fully support the stratigraphic subdivision of late Quaternary deposits of the Po Basin into transgressive-regressive sequences, rather than depositional sequences. The sequence-bounding unconformities do not display distinctive geochemical signatures.

Recent studies carried out on fine-grained sediments recovered from boreholes in the eastern plain of the Po River demonstrate that significant mineralogical and geochemical changes in the provenance of sediments occurred in coincidence with the Pleistocene-Holo-cene transition. An increase in ultramafic-sourced sediment, related to more important inputs from the Po River, is evident at the beginning of the Holocene. The effects of grain-size distribution and provenance variation were investigated on recent unconsolidated sediments, mainly silts and clays. Sediments were collected from ten boreholes in the area, and the geochemical and mineralogical data were compared to the grain-size data. Among the chemical indexes, Zr/V, Y/Rb, Y/V, SiO 2 /Al 2 O 3 , Fe 2 O 3 /SiO 2 , Na/Al increase from pure clay to fine sand together with some mineralogical ratios, including quartz/interstratified illite-smectite and feldspar/interstratified illite-smectite. Some provenance indexes, both mineralogical and geochemical (Ni/Al, Cr/Al, serpentine/sheet silicates), were found to be independent from grain-size and are therefore valid for a wide textural range of sediments. Several geochemical and mineralogical proxies for grain size were identified. In the present case, all these indexes are independent from provenance influence and can be used as direct proxies for the grain size of the sediment, as confirmed by the multiple regression analysis performed to evaluate median and sorting. The equations included the most significant ratios and work well for median values <30 μm.

The Paleogene turbiditic sedimentation in the eastern Southern Alps represents the sedimentary response to tectonic activity related to the Mesoalpine phase, which involved the surrounding chains from Paleocene time onward. Field and petrographic analyses have allowed us to classify these turbiditic successions as multisource deposits, as demonstrated by the common presence of allochemical, mainly bioclastic detritus, associated with different types of terrigenous arenites. For all units, field data suggest more proximal sources for allochemical supply and distal sources for terrigenous material, characterized by the presence of chert, carbonate rocks, and metamorphic rock fragments. All the investigated successions display transparent heavy mineral associations, marked by the common presence of chrome spinel, alkaline amphibole, staurolite, epidote, and zoisite, which point to similar metamorphic sources. The location of the source of metamorphic rock fragments is uncertain, but inputs from the internal Dinaric belt are possible. The source of the allochemical detritus was located in the nearby reactivated Friuli Platform.

The Modena alluvial plain is located on the northern side of the northern Apennines fold-and-thrust belt, where streams draining the chain flow toward the northeast into the Po River. The alluvial plain is characterized by a spectacular abundance of archaeological sites of various ages and can be considered a natural laboratory for the reconstruction of the recent sedimentary evolution of the Po Plain. Detailed modal analyses of modern sands of the Modena Plain streams indicate that the provenance signal can be distinguished on the basis of key components, such as quartz, feldspar, carbonate, and lithic fragments. The compositional fields of the streams depend on the extent of the watershed, the recycling of older fluvial sediments, and the sediment input from tributary streams. The modal analyses demonstrate that sand composition of the major rivers (Panaro and Secchia) has not changed during the Holocene, when sediment production, storage, and dispersal were probably dominated by colluvial aggradation in an environment characterized by dense vegetation cover. In the late Pleistocene, fluvial sands were characterized by higher feldspar contents compared with modern and Holocene sands. This feldspar abundance could reflect a high-frequency signal in sediment supply rates linked to secular variations of weathering processes, and it reveals the strong denudation and sediment removal conditions of the last glacial stage (15–18 ka). The implication of this study is that provenance of Holocene sediments now buried in the floodplain can be determined by a simple comparison with modern sand composition. Sand composition studies may represent a useful tool to reconstruct the Pleistocene-Holocene fluvial sediment supply and the evolution of human settlements as function of climate and drainage system changes.

Provenance studies most commonly apply the classical approach based on petrographic modal analysis of arenites. In this paper, a modal analysis of arenites is combined with both a petrographic study on conglomerate clasts and a geochemical investigation of major and trace elements of pelites. The Ligure-Piemontese oceanic basin, a branch of Western Tethys, and its continental margins were consumed during the Eocene collisional events that led to the formation of the Alpine-Apennine belt. Remnants of Cretaceous sedimentary successions supplied by the continental margins are today preserved as tectonic units in the Alpine-Apennine belt: Balagne Nappe in Alpine Corsica and Internal and External Ligurian units in the Northern Apennines. The petrography of pebbles from rudites and lithic fragments from are-nites shows that Corsica and Internal Ligurian units contain debris from granitoids, low-grade metamorphic rocks, and carbonate platform rocks, while the External Ligurian units contain debris from low- to high-grade metamorphic rocks, a mantle-rock source, carbonate platform, and pelagic siliceous and carbonate rock sources. Geochemical data on pelites indicate a more mafic-ultramafic character for External Ligurian units (enrichment in Cr, Co, Ni, and Th/Sc/Cr/V/Ni relationships that show a systematic shift toward an ultramafic contribution). Petrographic and chemical data indicate that the source for sediments of Corsica and Internal Ligurian units was made up of the upper part of a continental basement and its carbonate sedimentary cover (the Corsica-Europe continental margin). On the other hand, the External Ligurian units were supplied by a source area where a complete lithospheric section was exposed, from the upper mantle up to the deep-sea sedimentary cover (the Adria continental margin). These findings are useful in order to unravel the processes related to the opening mechanisms of the Ligure-Piemontese oceanic basin: among the different rifting models in existence, our data support an asymmetric mechanism dominated by a west-dipping detachment fault, with the Adria margin acting as the lower plate.

The Macigno is a widely outcropping terrigenous turbidite succession, up to 3000 m thick, in the northern Apennines. It was deposited in an Upper Oligocene–Lower Miocene perisutural basin that flanked the Apennine chain during uplift. In the Abetone study area, the Macigno lithofacies are characterized downward by prevailing thick-bedded, frequently amalgamated coarse sandstones (lower Macigno) and upward by recurrent fine and thin-bedded turbidites and siltstones (upper Macigno). The paleocurrent indicators are generally oriented toward the southeast and east. In the upper Macigno, a 250-m-thick intercalation known as the “Monte Modino Olistostrome” is present, represented by Cretaceous to Oligocene, locally chaotic, varicolored shale, marl, and limestone. Some authors hold that the latter is really an olistostrome that briefly interrupted the turbidite sedimentation. Others interpret the intercalation as the stratigraphic base of a tectonic unit that was thrusted onto the lower Macigno. Detailed modal petrographic analyses (Gazzi-Dickinson) performed on medium- to coarse-grained sandstones of the turbidite succession, along with plots of the data following the stratigraphic order of the samples, help to solve the geologic debate on stratigraphic continuity or tectonic discontinuity of the succession. The new data show that: (1) the main (QFL + C) and secondary components (Lv, Lm, Ls + C) are substantially similar along the succession; (2) from the stratigraphic base to the top of the turbidite succession, the petrographic parameters are characterized by appreciable trends and variations; and (3) the shaly-marly-calcareous intercalation (i.e., the Monte Modino Olistostrome) does not interrupt these trends and fluctuations. Therefore, we suggest that: (1) there is an overall common source area for the turbidite beds, even if minor compositional variations occur; and (2) the Macigno is a thick, stratigraphically continuous succession, and the sedimentary emplacement of the Monte Modino Olistostrome briefly interrupted the turbidite sedimentation. The new results contribute to geological mapping, to local- and regional-scale correlations, and to a better definition of the paleogeographic and tectonic setting of the Oligocene-Miocene siliciclastic turbidite successions of the northern Apennines.

In the central Apennines, interacting siliciclastic and carbonate marine clastic wedges filled the foreland basin system during the late Miocene. Conjunction of collisional thrust tectonics and prethrusting normal faults generated a complex foredeep with intrabasinal structural highs that represented additional source areas to the basin. Detrital modes of the late Miocene central Apennines orogenic system range in composition from intrabasinal carbonate to quartzofeldspatholithic and calclithite arenites. The external zone of the foredeep is characterized by hemipelagic deposits, called the Orbulina Marl. Their arenite beds are composed by intrabasinal carbonate, with dominant bioclasts and minor intraclasts, and glauconite derived from an active shallow-marine carbonate source. These hemipelagic deposits are partly coeval with and partly overlain by siliciclastic turbidites of the Frosinone and the Argilloso-Arenacea Formations, and they represent deposition within local foredeep depocenters. Siliciclastic turbidite sandstones are quartzofeldspatholithic, which documents provenances from metamorphic, plutonic, ophiolitic, and sedimentary rocks. Carbonate intrabasinal structural highs were the main source for carbonate breccias, intrabasinal arenites, and calclithites of the Brecce della Renga Formation, the deposits of which are locally interbedded with the coeval siliciclastic turbidite sandstones. Evolution of late Miocene sandstone detrital modes reflected the changing nature of the central Apennines thrust belt through time and the complex architecture of the foreland basin system; it records the history of accretion, deformation of the foredeep, and progressive areal reduction of carbonate-producing areas along with the sedimentary and structural evolution of local intrabasinal highs.

Detrital evaporites and mixed siliciclastic-gypsum arenites are present in the Gessi Formation from the Rossano Basin in Calabria, Italy. The detrital origin of the gypsum fragments in the quartzofeldspathic sandstones is revealed by crystal overgrowths that outline the shape of former gypsum clasts. The gypsum was subsequently transformed into anhydrite at burial conditions. During exhumation, anhydrite was hydrated back to gypsum, a gypsum overgrowth rich in F, Na, K, Cl, and Al formed on the original gypsum grains, and the pore spaces were filled with gypsum cement. Detrital modes of Gessi Formation sandstones suggest complex source-basin relationships in this area during the Messinian salinity crisis. The clastic deposits are the result of deep unroofing of the crustal terranes of the Calabrian arc and the reworking of primary Messinian evaporite facies (selenite). This study indicates that detrital evaporites and mixed siliciclastic-gypsum arenites are more widespread in the Mediterranean area than generally described in the literature.

This work represents an integrated analysis of weathering landforms, including minor landform morphologies and soil profiles developed on granitoid terrains of the Sila Massif uplands (Calabria, southern Italy). The results of our analysis indicate that cryoclastic and thermoclastic processes, along with chemical weathering, are the main factors controlling rock degradation. Microscale features observed in primary minerals and parent rock fabrics, such as structural discontinuities, cleavage planes, fracturing patterns, and variations in chemical composition, play important roles in triggering weathering and, given sufficient time, progressively lead to grussification and soil development. Exfoliation, hydration, and splitting apart of biotite, as well as hydrolysis and etching of plagioclase and K-feldspar, appear to be prominent factors in the breakdown of bedrock. Whereas time controls the degree of development of the main weathering features and climate infiuences type and intensity of the dominant processes, relief strongly influences the development and preservation/removal of the regolith/soil cover. Geomorphological evidence of severe surface erosion is quite good, especially along steep slopes where weathering products are quickly removed, although on the highest, dissected paleosurfaces (the oldest paleolandscape remnants in the Sila Massif), wide boulder fields represent relics of past, deep spheroidal weathering that have been exhumed by intense erosion. Erosive, depositional, or reworking phenomena, often enhanced by human activity, are well recorded by macro- and micromorphological features of soils, which show simple, poorly differentiated, rejuvenated profiles, buried or truncated horizons, abundant coarse-grained primary minerals or rock fragments, and pedorelicts. The soil clay mineralogy, characterized by illite, chlorite, and vermiculite, and the dominance of coarse textures confirm a young pedogenetic stage of evolution, although highly weathered sand grains (quartz included) occur in rarely preserved mature paleosols. This interpretation is also consistent with the compositional immaturity of fiuvial sands, which have undergone low to moderate transport.

We analyzed modern fluvial sands in the Iberian Range in order to obtain an accurate description of the different typologies of carbonate grains and to interpret their origin. Head streams of the Iberian Range mainly receive carbonate sediments as (1) fragments from ancient carbonate rocks, and (2) penecontemporaneous carbonate grains generated in the fluvial channels or in associated subenvironments. The erosion of proximal carbonate sources (Jurassic and Cretaceous in age) contributes to the generation of carbonate rock fragments. In addition, erosion of recent freshwater tufas, carbonate soils, and other recent carbonates produces an important volume of penecontemporaneous carbonate particles. Temperate to subhumid climate and short transport conditions promote good preservation of the composition and textures of carbonate grains in modern fluvial sands. Detailed petrographic analyses on penecon-temporaneous carbonates provide diagnostic clues of their origin. Four main petrographic classes of penecontemporaneous grains have been established: (1) penecon-temporaneous micritic grains, which are composed of microcrystalline calcite with a filamentous or laminated microfabric, are derived from erosion of recent freshwater carbonate tufas. Penecontemporaneous micritic grains with alveolar microfabric are derived from recent carbonate soils. (2) Penecontemporaneous sparitic grains, which are composed of single crystals or of mosaics with filamentous microfabric, are the result of erosion of carbonate tufas. Other penecontemporaneous sparitic grains include Microcodium and speleothems fragments. (3) Penecontemporaneous coated grains, which are composed of a nucleus plus a coating of penecontemporaneous carbonate, represent bioinduced carbonate particles (cyanoliths) that originate in streams. (4) Penecontemporaneous bioclasts, made from charophytes, ostracods, and mollusks, are rare. Identification of these grain categories in ancient deposits has implications for coeval carbonate supplies during fluvial sedimentation.

Petrography, geochemical whole-rock composition, and chemical analyses of tourmaline were performed in order to determine the source areas of Lower Cretaceous Mora, El Castellar, and uppermost Camarillas Formation sandstones from the Iberian Chain, Spain. Sandstones were deposited in intraplate subbasins, which are bound by plutonic and volcanic rocks of Permian, Triassic, and Jurassic age, Paleozoic metamorphic rocks, and Triassic sedimentary rocks. Modal analyses together with petrographic and cathodoluminescence observations allowed us to define three quartz-feldspathic petrofacies and recognize diagenetic processes that modified the original framework composition. Results from average restored petrofacies are: Mora petrofacies = P/F >1 and Q(r) 70 F(r) 22 R(r) 9 ; El Castellar petrofacies = P/F >1 and Q(r) 57 F(r) 25 R(r) 18 ; and Camarillas petrofacies = P/F ∼ zero and Q(r) 64 F(r) 28 R(r) 7 (P—plagioclase; F—feldspar; Q—quartz; R—rock fragments; r—restored composition). Trace-element and rare earth element abundances of whole-rock analyses discriminate well between the three petrofacies based on: (1) the Rb concentration, which is indicative of the K content and reflects the amount of K-feldspar modal abundance, and (2) the relative modal abundance of heavy minerals (tourmaline, zircon, titanite, and apatite), which is reproduced by the elements hosted in the observed heavy mineral assemblage (i.e., B and Li for tourmaline; Zr, Hf, and Ta for zircon; Ti, Ta, Nb, and their rare earth elements for titanite; and P, Y, and their rare earth elements for apatite). Tourmaline chemical composition for the three petrofacies ranges from Fe-tourmaline of granitic to Mg-tourmaline of metamorphic origin. The three defined petrofacies suggest a mixed provenance from plutonic and metamorphic source rocks. However, a progressively major influence of granitic source rocks was detected from the lowermost Mora petrofacies toward the uppermost Camarillas petrofacies. This provenance trend is consistent with the uplift and erosion of the Iberian Massif, which coincided with the development of the latest Berriasian synrift regional unconformity and affected all of the Iberian intraplate basins. The uplifting stage of Iberian Massif pluton caused a significant dilution of Paleozoic metamorphic source areas, which were dominant during the sedimentation of the lowermost Mora and El Castellar petrofacies. The association of petrographic data with whole-rock geochemical compositions and tourmaline chemical analysis has proved to be useful for determining source area characteristics, their predominance, and the evolution of source rock types during the deposition of quartz-feldspathic sandstones in intraplate basins. This approach ensures that provenance interpretation is consistent with the geological context.

Following the Variscan orogeny, the Iberian plate was affected by an extensional tectonic regime from Late Permian to Late Cretaceous time. In the central part of the plate, NW-SE–trending rift basins were created. Two rifting cycles can be identified during the extensional stage: (1) a Late Permian to Hettangian cycle, and (2) a latest Jurassic to Early Cretaceous cycle. During these cycles, thick clastic continental sequences were deposited in grabens and half grabens. In both cycles, sandstone petrofacies from periods of high tectonic activity reveal a main plutoniclastic (quartzofeldspathic) character due to the erosion of coarse-grained crystalline rocks from the Hesperian Massif, during Buntsand- stein (mean Qm 72 F 25 Lt 3 ) sedimentation and during Barremian–early Albian times (mean Qm 81 F 18 Lt 1 ). Geochemical data show that weathering was more intense during the second rifting phase (mean chemical index of alteration [CIA]: 80) due to more severe climate conditions (humid) than during the first rifting phase (mean CIA: 68) (arid climate). Ratios between major and trace elements agree with a main provenance from passive-margins settings in terms of the felsic nature of the crust. However, anomalies in trace elements have been detected in some Lower Cretaceous samples, suggesting additional basic supplies from the north area of the basin. These anomalies consist of (1) low contents in Hf, Th, and U; (2) high contents in Sc, Co, and Zr; and (3) anomalous ratios in Th/Y, La/Tb, Ta/Y, and Ni/V. Basic supplies could be related to the alkaline volcanism during Norian-Hettangian and Aalenian-Bajocian times. Geochemical composition of rift deposits has been shown to be a useful and complementary tool to petrographic deduction in provenance, especially in intensely weathered sediments. However, diagenetic processes and hydrothermalism may affect the original detrital deposits, producing changes in geochemical composition that mislead provenance and weathering deductions.

A vertical section of Upper Paleozoic sandstones from southern Transdanubia (Mecsek-Villány area, Tisza mega-unit, Hungary) has been analyzed for major and trace elements, including rare earth elements (REEs). In addition, the clay mineralogy of the sandstone samples and the petrography and geochemistry of gneiss and granitoid clasts extracted from the associated conglomerates have been determined. Geochemistry of the sandstone samples analyzed in this study shows that these rocks were predominantly derived from a felsic continental source; nevertheless, compositions vary systematically up-section. The Pennsylvanian (Upper Carboniferous) Téseny Formation has higher SiO 2 and lower Na 2 O, CaO, Sr, high field strength element (HFSE), and ΣREE contents relative to the Permian strata. Its high K 2 O and Rb contents together with the presence of abundant illite-sericite suggest a potassium metasomatism in this formation. Clay mineralogy and large ion lithophile element (LILE) contents of the Lower Permian Korpád Formation vary spatially and are interpreted as local variations in composition of the source region and postdepositional conditions. Zr and Hf abundances and REE patterns, however, show that this formation was derived from mature upper continental crust. The Upper Permian Cserdi Formation has higher TiO 2 , Th, U, Y, Cr, and heavy (H) REE contents, and higher Cr/Th and Cr/Zr ratios relative to the underlying formations. These trends can be explained by a sedimentary system dominated by highly weathered detritus derived from combined recycled-orogen, basement-uplift, and volcanic-arc provenance in the Téseny Formation, with an increased proportion of less weathered detritus derived from combined volcanic and basement-uplift provenances in the Permian formations. Characteristics of the Cserdi unit may reflect relatively proximal derivation from a felsic volcanic source.

A stratigraphic problem in most Gondwana basins in peninsular India has persisted for more than a century. Originally, in the type area of Damodar valley, the stratigraphy was established based on the order of superposition without the aid of fossils. However, fossils were used to classify the Gondwana succession into Lower Gondwana (Early Permian to Late Triassic), characterized by Glossopteris flora (considered to have become extinct by the end of Triassic), and Upper Gondwana, which has Ptilophyllum flora (Jurassic). The problem started as the work extended further outside the type area, where Glossopteris flora was discovered in Upper Gondwana rocks of Early Jurassic age. At this point, fossils took precedence in determining the relative age of strata under the assumption that Glossopteris flora could not extend beyond the Triassic. Therefore, Glossopteris -bearing Upper Gondwana–looking rocks were assumed to be of pre-Jurassic age. Thus, Upper Gondwana rocks were relegated to Lower Gondwana status. The confidence on fossils to determine the relative age of strata was so strong that the necessity to confirm their relative age based on the law of superposition was thought unnecessary. This happened in spite of the fact that ages based on a fossil are conceptual entities, whereas establishing the order of superposition is the ultimate proof of relative age of strata. Gondwana sedimentation coincided with the global climatic change from an ice-house state in the late Paleozoic to a greenhouse state in the Mesozoic. Climate played the most important role in controlling sandstone composition and other lithological attributes. A strong correlation between sand/sandstone composition and climate is well established. Any perceptible change in climate brings a perceptible change in sand/sandstone composition. Such compositional transition would be expected in the stratigraphic column as the climate changed between the two extremes. Sandstone composition of the Gondwana succession in the Raniganj basin, India, supports such a hypothesis. In addition, color of fine-grained rocks in the Gondwana succession, which to some extent is also influenced by climate, uniquely identifies each lithostratigraphic unit. Stratigraphy must be based on the law of superposition. But sandstone composition along with the color of fine-grained rocks could serve as additional criteria to stratigraphic interpretation. Such an approach may be useful in structurally overturned sequences and in reconstructing the subsurface stratigraphy from borehole cores.

The sand and gravel within the Waipaoa River system of North Island, New Zealand, elucidate the provenance and sedimentary delivery system of an actively deforming continental forearc. In this region, Mesozoic to Cenozoic forearc basin sedimentary successions are being uplifted, eroded, and recycled into younger deposits. The identification of specific characteristics of the drainage basin bedrock can be linked to sediment composition, which in turn can document the processes of provenance mixing and dilution. Despite the proximity of the Waipaoa River to an active volcanic arc (∼250 km), its sediment load includes a relatively small proportion of volcanic debris. Sand detrital modes and clast count data indicate that Waipaoa River sediments are dominated by the crushed and sheared sedimentary rocks of the East Coast allochthon, which is located in the upper portion of the catchment. Higher volcanic percentages in the Waimata and Te Arai Rivers suggest that the volcanic contribution in the Waipaoa River has likely been diluted by the great volume of sediment brought into the system from the large gullies in the catchment headwaters. Petrographic analysis of sand subfractions (very fine to very coarse) of Waipaoa River system sediment samples indicates that there is a distinct relationship between the size of the grains and their respective composition. Quartz and feldspar grains are concentrated in the finer fractions, reflecting the grain size of detrital sand liberated from Mesozoic to Cenozoic sandy source rocks. Thus, their distribution is at least in part an inherited feature related to sediment recycling within the system. Most of the sediment (gravel and sand) consists of mudstone and claystone lithic fragments. In the Waipaoa River, the sand is dominated by noncalcareous mudstone lithic fragments, some of which are smectitic. In the Waimata River, the sand grains are mainly calcareous mudstone lithic fragments. This difference in rock-fragment type reflects differences in mud rock source lithologies. Similar trends are observed in the gravel fractions of the Waipaoa River, with noted increases in calcareous gravel components in the river where it (or tributaries) traverse calcareous lithologies. These compositional differences suggest that in future studies of older alluvium and offshore sedimentary sections, it may be possible to distinguish coarse sediment derived from a purely Cenozoic source from that derived from Mesozoic rocks in the upper catchment of the Waipaoa River system, allowing us to interpret drainage evolution and denudation patterns.

Off the east coast of South Island, New Zealand, the Bounty Fan lies in the most seaward axial deep of the Bounty Trough, a remnant continental rift. The north levee of the Bounty Channel was cored at Ocean Drilling Program (ODP) Site 1122 on Leg 181. The 617 m section, which is divided into three units and nine subunits, consists of a Quaternary fan turbidite sequence that transitions downward into a Pleistocene to Pliocene mixed turbidite to contourite facies, which unconformably overlies a Miocene contourite-pelagic succession. Petrographic analysis (point counts) of 55 fine to very fine sand samples across the cored interval shows them to be quartzofeldspathic with moderate mica and minor metamorphic lithic components (mean values = Q 44 F 44 L 12 , Qm 50 K 3 P 47 , Lm 70 Lv 4 Ls 26 , total%mica 14 ). Mean recalculated parameters for Site 1122 units and subunits cluster on QFL, QmKP, and LmLvLs ternary plots with little compositional variation. Proportions of biotite, muscovite, chlorite, and various metamorphic lithic types also show little compositional variation among the units and subunits of Site 1122. Furthermore, there are no significant trends among thickness, grain size, composition, and depth of Site 1122 sand samples, except that thicker beds tend to contain slightly more metamorphic rock fragments. The generally homogeneous composition of Site 1122 sand indicates that it may have had a relatively uniform source back into the early Miocene. Thus, the up-section change from sandy contourite to turbidite deposits at Site 1122 is not reflected in sand composition. This suggests that the sand provenance remained constant while the depositional processes of sand at Site 1122 changed. Sand detrital modes at Site 1122 most closely match those of the Clutha River, especially in terms of QFL, QmKP, mica, and lithic proportions, suggesting that it was a major source of sand at Site 1122. However, admixing of sand from the Waitaki River and other sources cannot be completely ruled out.

The purpose of the study is to (1) identify the sources of sediment in various environments, (2) define the history and transport processes of the sediments, and (3) better understand the erosion and potential replenishment of the local beaches along the southern coast of the Baja California peninsula. For the purpose of this study, six naturally defined areas were studied separately: El Cardonal, El Arco, San Lucas, El Tiburón, El Tule, and San José. Two main sedimentary provinces were identified via Fourier grain-shape analysis, El Médano and Los Cabos. El Médano sedimentary province includes the El Cardonal and El Arco areas, which are influenced by the dynamics associated with the Pacific Ocean dominated by northwesterly winds, waves, and longshore transport. Beaches from this province have a source mostly from marine material from the shallow shelf, and they are dominantly affected by longshore transport. Secondarily, they are dominated by old and recent aeolian material dissected by intermittent arroyos and local arroyo material from intrusive rocks. The Los Cabos sedimentary province includes the other four areas, and it is influenced by the dynamics of the Gulf of California. In this province, dominant southerly waves are present. Sediment transport occurs along the coast from southwest to northeast; although, some beaches contain material from northern areas, probably related to the direction of waves and sediment transport direction during meteoric events such as hurricanes. Beaches from this province have a source mostly from local arroyo material from intrusive rocks. Other beach material results from longshore transport and some material comes from the El Médano sedimentary province in the El Arco boundary area. Grain-shape data and the information associated with elongation (harmonic 2) show that marine samples (beach, shallow, and deep inner continental shelf) from Los Médanos sedimentary province contain high frequencies of grains with low elongation, opposite of the arroyo samples. This suggests that the low elongation grain source may be farther north of this province. In the Los Cabos sedimentary province, the local arroyos and the longshore transport have been identified as the major factors that nourish and distribute the beach material along the coast. The results of this study parallel those found in similar geographic regions where storms rather than steady currents dominant.

Single-grain, laser-ablation inductively coupled plasma–mass spectrometry analyses of detrital apatites from Pliocene sandstones in the South Caspian Basin (Azerbaijan) and Devonian-Carboniferous sandstones from Clair oil field, west of Shetland (UK), demonstrate that apatite geochemistry has significant potential in provenance analysis. Apatites in Pliocene sandstones deposited by the paleo-Kura River system, which drained the Lesser Caucasus region, were derived largely from mafic to intermediate and alkaline rocks. Apatite populations in Pliocene sediments transported by the paleo-Volga River system, which drained the Russian Platform, show greater compositional diversity and indicate supply from granitoids or other acidic rocks together with subordinate mafic to intermediate and alkaline rocks. Apatites in the Devonian-Carboniferous succession west of Britain were derived predominantly from acidic rocks, either directly from Archean gneisses or indirectly from metasedimentary rocks. In the two case studies, the most useful discriminators of apatite provenance proved to be La/Nd and La + Ce/ΣREE. Since apatite is stable during burial in sedimentary basins, apatite geochemistry can be used to determine provenance of sandstones from the full range of diagenetic environments, although the instability of apatite during weathering means that the method will be difficult to apply to sandstones with prolonged weathering history. At present, identification of provenance using apatite geochemistry is limited by the lack of a comprehensive database on apatite compositions in some of the potential source rocks, particularly those of metamorphic origin. The role played by sediment recycling is another factor that requires consideration when reconstructing source areas on the basis of apatite compositions.