Abstract The Late Pennsylvanian was a time of ice ages and climate dynamics that drove biotic changes in the marine and non-marine realms. The apex of late Paleozoic glaciation in southern Gondwana was during the Late Pennsylvanian, rather than the early Permian as inferred from more equatorial Pangaea. Waxing and waning of ice sheets drove cyclothemic sedimentation in the Pangaean tropics, providing an astrochronology tuned to Earth-orbital cycles, tied to climatic changes, reflected in aeolian loess and palaeosol archives. Vegetation change across the Middle–Late Pennsylvanian boundary was not a ‘Carboniferous rainforest collapse’, but instead a complex and drawn out step-wise change from one kind of rainforest to another. Changes in marine invertebrate and terrestrial vertebrate animals occurred across the Middle–Late Pennsylvanian boundary, but these did not lead to substantive changes in the organization of those communities. The base of the Upper Pennsylvanian is the base of the Kasimovian Stage, and this boundary needs a GSSP to standardize and stabilize chronostratigraphic usage. To avoid further chronostratigraphic confusion, the Cantabrian Substage should be abandoned, and the traditional Westphalian–Stephanian boundary should be returned to and recognized as the time of major floristic change, the lycospore extinction event.

Abstract Palaeo-loess and silty aeolian-marine strata are well recognized across the Carboniferous–Permian of equatorial Pangaea. Aeolian-transported dust and loess appear in the Late Devonian in the west, are common by the Late Carboniferous, and predominate across equatorial Pangaea by the Permian. The thickest loess deposits in Earth history – in excess of 1000 m – date from this time, and archive unusually dusty equatorial conditions, especially compared to the dearth of equatorial dust in the Cenozoic. Loess archives a confluence of silt generation, aeolian emission and transport, and ultimate accumulation in dust traps that included ephemerally wet surfaces and epeiric seas. Orogenic belts sourced the silt, and mountain glaciation may have exacerbated voluminous silt production, but remains controversial. In western Pangaea, large rivers transported silt westward, and floodplain deflation supplied silt for loess and dust. Expansion of dust deposition in Late Pennsylvanian time records aridification that progressed across Pangaea, from west to east. Contemporaneous volcanism may have created acidic atmospheric conditions to enhance nutrient reactivity of dusts, affecting Earth's carbon cycle. The late Paleozoic was Earth's largest and most long-lived dust bowl, and this dust represents both an archive and agent of climate and climate change.

ABSTRACT Jurassic northward migration of Mexico, which lay on the southern part of the North America plate, resulted in temporal evolution of climate-sensitive depositional environments. Lower–Middle Jurassic rocks in central Mexico contain a record of warm-humid conditions, indicated by coal, plant fossils, and compositionally mature sandstone deposited in continental environments. Paleomagnetic data for central Oaxaca and other regions of central and eastern Mexico indicate that Lower and Middle Jurassic rocks were deposited at near-equatorial paleolatitudes. In the Late Jurassic, the Gulf of Mexico formed as a subsidiary basin of the Atlantic Ocean when the Pangea supercontinent ruptured. Upper Jurassic strata across Mexico, including eolianite and widespread evaporite deposits, indicate dry-arid conditions. Available paleomagnetic data (compaction-corrected) from southern and northeast Mexico for Upper Jurassic strata indicate deposition at ~15°N–20°N. As North America moved northward during Jurassic opening of the Atlantic Ocean, different latitudinal regions experienced coeval Middle–Late Jurassic climatic shifts. Climate transitions have been widely recognized in the Colorado Plateau region. The plateau left the horse latitudes in the late Middle Jurassic to reach temperate humid climates at ~40°N in the latest Jurassic. Affected by the same northward drift, the southern end of the North America plate represented by central Mexico gradually reached the arid horse latitudes in the late Middle Jurassic as the Colorado Plateau was leaving them. As a result, Late Jurassic epeiric platforms developed in the circum–Gulf of Mexico region after a long period of margin extension and were surrounded by arid land masses. We propose that hydrocarbon source-rock deposition was facilitated by arid conditions and wind-induced coastal upwelling.

Abstract The post-obduction formations of Grande Terre, New Caledonia, comprise igneous intrusions, regolith cover, and marine and terrestrial sedimentary rocks. Two restricted Late Oligocene granitoid bodies are intruded into the Peridotite Nappe and its substrate in the south of the island. Thick regolith cover developed over the Peridotite Nappe from the Late Oligocene or earlier. The Népoui Group comprises Late Oligocene–Early Miocene mixed marine carbonate and siliciclastic deposits. It mainly reworks the Peridotite Nappe and its regolith cover. Its development pattern is mainly controlled by tectonic uplift and subsidence. The Gwa N'Doro Formation on the eastern coast and the Fluvio-lacustrine Formation in the south are remnants of the Miocene–Present river network. Offshore, thick Oligocene to Neogene sedimentary successions are imaged by seismic surveys on the margins of Grande Terre, although these successions have not been drilled and remain undated. Several dredges have recovered shallow Miocene sedimentary rocks, indicating substantial Neogene subsidence. Quaternary formations are represented inland by aeolianite, vertisols and calcrete and offshore by the large barrier reef–lagoon complex, the onset of which is dated at c. 400 ka. This chapter discusses the different models proposed for the post-obduction evolution of Grand Terre.

ABSTRACT The Devonian System in the Kingdom of Saudi Arabia (KSA) forms a significant part of the Paleozoic succession on the Arabian plate and was deposited on an extensive coastal plain to shoreline to shallow continental shelf, dipping slightly to the north and east. The Devonian succession attains a thickness of nearly 2.5 km (8200 ft), though a significant part of this thickness is from the reconstructed Jubah Formation in deep basins to the east and north of KSA. The Devonian Jauf Formation is an important siliciclastic gas-bearing and producing reservoir in eastern Saudi Arabia, and it formed within a second-order progradational megasequence, lasting from the latest Ordovician to the culmination of the Hercynian orogeny in the very early Carboniferous. It also includes proven source-rock intervals related to plate-wide flooding events. We recommend that the top of the Jauf Formation, in the subsurface of the Eastern Province, be raised approximately 120–130 m (390–430 ft) higher than the currently adopted top by Saudi Aramco staff, to include all strata that are considered as part of Jubah by Saudi Aramco current usage. The present Jauf top (Saudi Aramco’s operational Jauf top) is picked at the top of a biostratigraphic zone (D3A), a practice not recommended by the code of stratigraphic nomenclature for formational tops. The contact this chapter proposes coincides with a prominent lithological change that marks a third-order sequence boundary (SB70). We believe that this distinct disconformable contact is of regional significance. We reconstruct the Jauf depositional systems using subsurface and outcrop data, emphasizing key regressive deltaic and transgressive estuarine shorelines as well as and associated fluvial, paralic, and shelf deposits. We demonstrate the importance of the fundamental fourth-order shelf-transiting sequences and larger third-order host sequences in the very extensive Devonian Arabian shelf building. We also draw contrasts between the Jauf Formation development in the outcrops of northwest KSA (including carbonate embayments) and those in the subsurface of the east and southeast parts of the KSA (wave-dominated strandplains and deltas and tide-influenced estuaries), where there was stronger fluvial supply. The Devonian Jauf shorelines show truly spectacular regressive and transgressive transits for hundreds of kilometers across the wide shallow shelf that sloped gently off the Arabian shield. In eastern KSA’s producing fields, the revised Jauf Formation thickens toward the east-northeast from 170 m (557 ft) to 343 m (1125 ft) and comprises three third-order sequences, referred to as SQ55, SQ60, and SQ65. Five new paleogeographic maps are presented for these three sequences. Each of the third-order sequences consists of several fourth-order sequences. Sequence SQ55 is dominated by a spectacular falling stage systems tract (forced regressive shoreface), which prograded from west to east across a distance of over 200 km (125 mi). The overlying sequences SQ60 and SQ65 each have a thick transgressive systems tract (TST) and a thinner highstand systems tract (HST). Depositional environments were mostly coastal plain and nearshore and ranged from wave-dominated shorefaces to tidally influenced estuarine embayment fills with tidal channels and bars to tidal and fluvial-dominated coastal-plain channels. Reservoir quality rocks are preferentially those deposited during the TST of SQ60 in tidal estuarine environments as channel-fills, bars, and bay-fill deltas. In these reservoirs, porosity was protected by grain-rimming clays from subsequent quartz cementation. The well-sorted shoreface facies, which dominates SQ55, tends to be of lower reservoir quality because of finer grain size and pervasive silica cementation.

ABSTRACT The Permian marks a time of substantial climatic and tectonic changes in the late Paleozoic. Gondwanan glaciation collapsed after its earliest Permian acme, aridification affected the equatorial region, and monsoonal conditions commenced and intensified. In western equatorial Pangea, deformation associated with the Ancestral Rocky Mountains continued, while the asynchronous collision between Laurentia and Gondwana produced the Central Pangean Mountains, including the Appalachian-Ouachita-Marathon orogens bordering eastern and southern Laurentia, completing the final stages of Pangean assembly. Permian red beds of the southern midcontinent archive an especially rich record of the Permian of western equatorial Pangea. Depositional patterns and detrital-zircon provenance from Permian strata in Kansas and Oklahoma preserve tectonic and climatic histories in this archive. Although these strata have long been assumed to record marginal-marine (e.g., deltaic, tidal) and fluvial deposition, recent and ongoing detailed facies analyses indicate a predominance of eolian-transported siliciclastic material ultimately trapped in systems that ranged from eolian (loess and eolian sand) to ephemerally wet (e.g., mud flat, wadi) in a vast sink for mud to fine-grained sand. Analyses of U-Pb isotopes of zircons for 22 samples from Lower to Upper Permian strata indicate a significant shift in provenance reflected in a reduction of Yavapai-Mazatzal and Neoproterozoic sources and increases in Grenvillian and Paleozoic sources. Lower Permian (Cisuralian) strata exhibit nearly subequal proportions of Grenvillian, Neoproterozoic, and Yavapai-Mazatzal grains, whereas primarily Grenvillian and secondarily early Paleozoic grains predominate in Guadalupian and Lopingian strata. This shift records diminishment of Ancestral Rocky Mountains (western) sources and growing predominance of sources to the south and southeast. These tectonic changes operated in concert with the growing influence of monsoonal circulation, which strengthened through Permian time. This resulted in a growing predominance of material sourced from uplifts to the south and southeast, but carried to the midcontinent by easterlies, southeasterlies, and westerlies toward the ultimate sink of the southern midcontinent.

ABSTRACT The Colorado Plateau in the southwestern United States is within the Paleozoic transcontinental arch, an area of thin, cratonic strata. The plateau was broken by latest Mississippian to early Permian Ancestral Rocky Mountain orogenesis, which produced bedrock uplifts that influenced lower Mesozoic sedimentation before Jurassic burial. Clastic sediments shed from uplifts interfinger with eolian Permian strata ultimately derived from eastern Laurentia. Triassic and Jurassic strata of the Colorado Plateau are here divided into five depositional systems, each representing a different sedimentary and tectonic setting and forming stratal associations referred to as “deposystems.” The five deposystems, which largely but not entirely correspond to formation or group names, were deposited during northward continental drift from tropical latitudes (fluvial, tidal, and nearshore marine Moenkopi and fluvial Chinle) through desert latitudes (the erg-dominated Glen Canyon and San Rafael) to temperate latitudes (fluvial Morrison). Paleomagnetically determined paleolatitudes, corrected for inclination shallowing due to postdepositional sediment compaction, place the Glen Canyon and San Rafael eolianites firmly within expected latitudes for desert environmental conditions. Lower Triassic strata of the Moenkopi deposystem form a westward-thickening wedge of fluvial and shallow marine strata and are overlain by entirely fluvial strata of the Chinle deposystem. Both contain 240–280 Ma detrital zircon populations derived from the east Mexico magmatic arc, but more northern Chinle fluvial deposits contain a higher fraction of zircons derived from Paleozoic, Neoproterozoic, and Grenville provinces in eastern Laurentia. Westward thickening of Moenkopi strata is attributed to subsidence in the proforeland basin of the east-vergent Sonoma orogeny in central Nevada, whereas accommodation space for Chinle sedimentation was provided by dynamic subsidence above the upper Triassic subduction zone behind the newly established Cordilleran magmatic arc to the southwest. Overlying, largely Jurassic Glen Canyon and San Rafael deposystems are dominantly eolian. Detrital-zircon geochronologic analysis indicates that eolian sands were derived largely from eastern Laurentia. Interbedded marginal marine, ­lacustrine-sabkha, and fluvial strata have been associated with regional unconformities, but evidence for such unconformities is here regarded as indicating facies transgressions without development of plateau-wide unconformities or disconformities. Upper Jurassic northward continental drift carried the plateau out of the desert belt and into the zone of prevailing westerly winds. This coincided with a flare up of magmatism in the Cordilleran magmatic arc, leading to transgression of Morrison fluvial sediments over erg deposits of the San Rafael deposystem. Eastward dispersal of Morrison sediments marked the initiation of the Cordilleran orogen as the dominant topographic feature of the plateau region.

The Arizaro Basin in northwestern Argentina sits today in the western Puna Plateau at elevations of 3800–4200 m along the eastern flank of the Miocene to modern magmatic arc. The basin is roughly circular in plan view and ~100 km in diameter, and it was filled during Miocene time (ca. 21–9 Ma) by >3.5 km of eolian, alluvial, fluvial, and lacustrine sediment in addition to ash-fall tuffs from the Andean magmatic arc. The basin fill was subsequently shortened in its central part, and it has been uplifted and topographically inverted. The Arizaro Basin is not obviously related to known faults, nor does it exhibit a peripheral belt of coarse-grained sedimentary rocks derived from flanking topographically higher regions. Sandstone modal framework compositions are arkosic, but not as rich in volcanic lithic fragments as typical intra-arc basins. Detrital zircon U-Pb age spectra implicate source terranes in locally exposed Ordovician granitoid rocks, more distal Upper Paleozoic–Mesozoic arc terranes in western Argentina and possibly northern Chile, and the local Miocene magmatic arc. Depositional-age zircons are present in most of the sandstones analyzed for detrital zircon U-Pb geochronology, and zircon U-Pb ages from volcanic tuff layers provide independent chronological control. The tectonic component of subsidence initiated at low rates, accelerated to ~0.6 mm/yr during the medial stage of basin development, and tapered off to zero as the basin began to shorten internally and experience topographic inversion after ca. 10 Ma. Together, the data presented here suggest that the Arizaro Basin could have developed in response to the formation and gravitational foundering of a dense Rayleigh-Taylor–type instability in the lower crust and/or mantle lithosphere. Insofar as hinterland basins of uncertain tectonic affinity are widespread in the high central Andes, the model developed here may be relevant for other regions of enigmatic subsidence and sediment accumulation in the Andes and other cordilleran hinterland settings.