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During its life span from mid-Carboniferous (320 Ma) merger to mid-Jurassic (160 Ma) initial breakup, Pangea comprised two contrasting sedimentary provinces: (1) an emergent southern (Gondwanaland) province, with no more than 15% of the landmass covered by the sea, dominated by nonmarine facies, and (2) a submergent northern or Laurasian province, 25% or more covered by the sea, dominated by marine facies. This contrast arose from the unequal size of Pangea’s original components. The 100-million-km 2 area of Paleozoic Gondwanaland, which generated a large heat anomaly in and beneath the lithosphere, dwarfed the 30-million-km 2 area of Laurentia and was 10 times the size of the two Chinese microplates. Pangea inherited the contrast and maintained it by the growth of its own heat anomaly. Within this overarching factor that distinguished northern from southern Pangea, plate-tectonic forces modulated by the growth of the Pangean heat anomaly brought about a sedimentary/tectonic evolution that reflects the repetition of couplets of shortening and extension. Initial Variscan/Appalachian (325 to 290 Ma) and Kanimblan/Alice Springs (350 to 325 Ma) collisional shortening and uplift were followed at 290 Ma by Extension I The lithosphere underwent thermal subsidence in modes that depended on basement structure: Hot, newly formed orogenic basement subsided in volcanic rifts, whereas cratonic basement types were nonvolcanic; the cratonic Proterozoic foldbelts of the Zambezian terrain subsided in linear fault-bounded zones or rifts; cratonic nuclei of the Karoo terrain subsided in oval-shaped basins or sags. Subsequent Gondwanide/Indosinian (255 to 230 Ma) shortening and uplift were followed at 230 Ma by Extension II, mainly by rifting. Final dispersal started when continental rifting was superseded by seafloor spreading. Glaciation in the Gondwanaland province during the Pennsylvanian-Permian and coal-forming conditions during the Pennsylvanian in Euramerica and Permian in the Gondwanaland province and Asia were terminated by global warming that accompanied excessive venting of CO 2 into the atmosphere during the eruption of the Permian/Triassic (~250 Ma) Siberian Traps and other volcanics. The resulting gap in coal deposition lasted through the Early and Middle Triassic until the excessive CO 2 was finally resorbed by the crust, at which time coal deposition resumed during the Late Triassic.

Profound short-lived events about the Permian/Triassic (P/Tr) boundary, determined here as 250 Ma, include (1) magmatic events: rapid eruption of the vast flood basalt of the Siberian Traps and the peak of convergent magmatism in the Gondwanaland province along the Panthalassan margin, represented in Australia by the Dundee/Emmaville Volcanics and in South America by the Choiyoi province; (2) paleoclimatic change: following the last ice-rafting dropstone in eastern Australia, an abrupt change from coal measures to redbeds in the Gondwanaland province; (3) biota extinctions: indicated by a minimum standing diversity of marine invertebrates and by the replacement of the Glossopteris flora by the 2Dicroidium flora; (42) a sea-level minimum; (5) seawater isotope changes: a minimum 87 Sr/ 86 Sr, a precipitous drop in δ 13 C, and a broad minimum in δ 34 S; (6) magnetic polarity shift: change from the Permo-Carboniferous Reversed Polarity Superchron to the Permo-Triassic Mixed Superchron. All but the demonstrably older magnetic polarity change are possibly synchronous, because any apparent differences in age fall within the uncertainties of measuring radiometric ages and of calibrating the biostratigraphic and radiometric timescales. Eastern Australia, which represents the Panthalassan margin of the Gondwanaland province, has a record in this stratigraphic order of the following abrupt changes at the P/Tr boundary: (3) sediment containing redbeds with Dicroidium replaces (2) the last Glossopteris in coal measures with thick tuff from eruption of the Emmaville Volcanics, and (1) the last ice-rafted dropstones. This chain of events is consistent with the following global model: (1) An abrupt change ~255 Ma in the heat regime at the core/mantle boundary generated a change of magnetic chron and released a mantle plume that erupted at the surface ~250 Ma as the Siberian Traps, at the same time as the peak of convergent volcanism along the Gondwanaland margin of Panthalassa. (2) The volcanics vented CO 2 that effected rapid warming by the greenhouse effect; (3) the resulting biotal extinctions and a decreased biomass caused lower organic productivity. (4) Oxidation of surface sediment, including progenitors of coal, led to a drop in seawater δ 13 C and, in much of Gondwanaland and China, a gap in the preservation of coal. (Seawater δ 13 C rose and the preservation of coal was resumed 20 m.y. later at 230 Ma in the Late Triassic.) (5) Warm surface water at high latitudes slowed bottom ocean-water circulation so that the ocean floor became anoxic.

Gondwanaland was reconstructed by first forming East Gondwanaland (India, Antarctica and Australia) and then closing East Gondwanaland to Africa with Madagascar in a tight northern fit against Somalia. The poles of rotation to form Gondwanaland follow Powell et al. (1988), Lawver and Scotese (1987), Lawver et al. (1992), and Veevers et al. (1991). Paleolatitudes found from the Gondwanan apparent polar-wander path documented by Li et al. (1993a, 1993b) show that South America and southern Africa were in high latitudes in the Devonian and Early Carboniferous, while Australia was in low latitudes, and that during the Late Carboniferous to the end of the Permian, Australia and adjacent Antarctica were in high latitudes while southern South America and southern Africa were in middle-to-low latitudes. The movement of the paleopole along the Panthalassan margin toward the Antarctic Peninsula during the Triassic to Early Jurassic placed most of the Panthalassan margin in middle to high latitudes during the early Mesozoic.

The Sydney-Gunnedah-Bowen Basin developed above the junction between (a) the western, early to mid-Paleozoic Lachlan and Thomson Fold Belts, terminally deformed and intruded in the mid-Carboniferous, and (b) the eastern, mid- to late Paleozoic New England Fold Belt (NEFB). Accordingly, the basement of the Sydney-Gunnedah-Bowen Basin varies along strike. In the south, the Sydney-Gunnedah Basin developed above the Late Devonian-Early Carboniferous Andean-type magmatic arc and fore arc, whereas in the north, the Bowen Basin developed behind the magmatic arc. The magmatic arc was displaced by crustal transtension during the latest Carboniferous-Early Permian. During transtension, the NEFB was intruded by S-type granitoids with co-magmatic ignimbrites and uplifted during right-lateral shearing to form the initial stage of an orocline. Thereafter to the end of the Triassic, eastern Australia developed through seven stages: Stage A (290-268 Ma), extension-volcanism of the collapsed Kanimblan-NEFB upland with thick volcanics and sediment, was a local manifestation of the first release of Pangean-induced heat and is comparable with the vast magmatic province of the same age that developed after the Variscan Orogeny in Europe. A glacio-eustatic marine transgression at 277 Ma crossed the NEFB to reach the newly formed Bowen and Sydney Basins. Stage B (268-258 Ma), a marine sag on the platform and embryonic magmatic arc/foreland basin, brought the sea to the western edge of the Bowen-Gunnedah-Sydney Basin and covered Tasmania. The first tuff attributable to the north-migrating convergent magmatic arc reached Tasmania 265 Ma, and the first convergent granitoid reached the NEFB also at 265 Ma and was followed by the deposition of coarse sediment in the embryonic foreland basin. Stage C (258-250 Ma), orogenic piedmont coal/tuff, initiated the foreland basin between the uplift of the mature NEFB and a foreswell that bounded the Galilee, Coorabin, and Tasmania Basins of the western craton.

The Permian-Triassic Transantarctic basin, which occupied the Panthalassan margin of the East Antarctic craton, including the present Transantarctic and Ellsworth Mountains, evolved above a mid-Paleozoic passive continental margin basement through the following stages: (1) Carboniferous/Permian extension, (2) late Early Permian back-arc basin, (3) Late Permian and Triassic foreland basin, and (4) Jurassic extension and tholeiitic volcanism. A mid-Paleozoic (Devonian) wedge of coastal-to-shallow marine quartzose sandstone developed on the eroded roots of the Late Cambrian-Early Ordovician Ross orogen. A lacuna in East Antarctica during the Carboniferous was followed by the inception of Gondwanan deposition in a wide Carboniferous/Permian extensional basin. Volcanic detritus at the base of the late Early Permian post-glacial marine(?) shale and sandstone sequence in the Ellsworth Mountains is the first sign of a volcanic arc and subduction along the Panthalassan margin. A similar but much thinner non-volcaniclastic sequence accumulated in the Transantarctic Mountains. The introduction of abundant volcanic detritus to the cratonic side of the basin and a 180° paleocurrent reversal in the Late Permian in the Beardmore Glacier area are the earliest indicators of tectonism along the outer margin of the basin and the inception of a foreland basin that accumulated thick Late Permian and Triassic braided stream deposits of mixed volcanic and cratonic provenance. The Permian sequences in the Ellsworth and Pensacola Mountains were folded in the Triassic. The foreland basin was succeeded in the Early Jurassic by extension and initial silicic and then tholeiitic volcanism that led to the breakup of Gondwanaland.

Three basement trends, defined by the 1.0–0.5 Ga foldbelts of weak crust that wrap around the 1 Ga Namaqua-Natal Belt and >2.5 Ga Kaapvaal Province, provide a tub-shaped template that was impressed on succeeding structures up to the Cretaceous breakup of Pangea along the present divergent margins. The pattern is reprinted during the Ordovician-Devonian deposition of the Cape Supergroup in grabens on the northwest and northeast linked by an east-west depositional axis and during the Permian and Triassic development of the Cape Fold Belt along the east-west trend linked with intermittent uplifts to the northwest (Atlantic upland) at a syntaxis around Cape Town and to the northeast (Eastern upland) at a syntaxis in the (restored) Falkland Islands. The inception of the Karoo (Gondwanan) Sequence in the latest Carboniferous (290 Ma) reflected the Gondwanaland-wide relaxation of the Pangean platform in sags (Karoo terrain) and rifts (Zambezian terrain). The first appearance of tuffs from a convergent arc in the Sakmarian (ca. 277 Ma) marked the onset of a foreland basin. Material derived from the south included a small component of mainly rhyodacitic tuff which persisted to the end of Beaufort deposition, when the presumed southern magmatic arc became extinct. Karoo deposition expanded northward over the interior beyond that of the confined pre-Gondwanan Cape Sequence. The axis of maximum thickness of the Permian-Triassic foredeep remained near the South Crop of the Karoo Basin; the parallel drainage axis migrated northward from an initial distance of 80 km during Dwyka deposition through 400 km during Ecca deposition and 550 km during Beaufort to a final 1,000 km during Stormberg deposition. The increasing separation of foredeep and drainage axis reflects the widening during the growth of the Cape Fold Belt of the southern depositional flank of the Karoo Basin at the expense of the starved northern cratonic side. Only during Stormberg deposition did the northern craton match the Cape Fold Belt as a source of voluminous sediment.

In central-western Argentina, the basement comprises Cambrian to Devonian sedimentary rocks, deformed and uplifted during the Late Devonian-earliest Carboniferous Chañic orogeny along the Paleo-Pacific margin of South America. Unconformably above basement, the Gondwana cycle comprises two unconformity-bounded sequences. The Visean (350 Ma) to earliest Permian (275 Ma) Lower Sequence started with deposition in the Andean (or western) Calingasta-Uspallata Basin of valley-fill sediments. By the Namurian, alpine glaciation of a basement ridge, the Proto-Precordillera, fed sediment into the marine Calingasta-Uspallata Basin on the west and the nonmarine western Paganzo Basin on the east. The Paganzo Basin received additional sediment shed from basement highs further to the east. Mainly marine (but not glacial) sediment continued to be deposited in the Calingasta-Uspallata Basin into the Early Permian (275 Ma). At the same time, the Paganzo Basin expanded as dominantly nonmarine sediment encroached eastward over the craton. Tuff first appeared in the earliest Permian (~286 Ma) and reflects initial input from the magmatic arc on the Panthalassan margin. At the same time sediment overlapped the Proto-Precordillera. Southward, in the Andean San Rafael Basin, a similar Lower Sequence started with glacial sediment, probably in the Namurian, and likewise concluded at 275 Ma. In east-central Argentina, in the Sauce Grande Basin, deposition did not start until the latest Carboniferous (~290 Ma), with a marine glacial deposit capped by Tastubian transgressive glaciomarine sandstone and shale. At about 275 Ma, the mild extensional tectonics that had generated the Lower Sequence of quartzofeldspathic petrofacies from the craton, and sedimentary-lithic petrofacies from the Proto-Precordillera, gave way to convergent magmatic-arc tectonics that generated the volcanic and volcaniclastic Upper Sequence, which continued to the end of the Permian. In the magmatic arc, the Choiyoi Group (275 to 250 Ma) of mainly dacitic ignimbrites merged eastward with volcaniclastics in the now-continuous Calingasta-Uspallata/western Paganzo foreland basin. Further east, in the Sauce Grande Basin, the Tunas Formation with tuffaceous interbeds conformably succeeded the glacial sediments. The tuffaceous interbeds reflect the southeastward swing of the arc at 34°S to parallel the axis of the Sauce Grande Basin 250 km away. The Gondwana cycle concluded with mild compressive deformation and uplift represented by an Early Triassic lacuna. Violent extensional deformation in the Middle and Late Triassic cut a swath of NW-trending grabens across northern Chile to Patagonia. The grabens filled with marine sediment in Chile and nonmarine alluvial-fan and then lacustrine-fluvial sediment in Argentina. The Late Paleozoic and Triassic succession was Anally capped by Late Jurassic and Early Cretaceous flood basalt.

The Permian-Triassic (Gondwanan) basins and foldbelts along the Panthalas-san margin of the Gondwanaland province of Pangea developed on a basement of Proterozoic and Paleozoic rocks in Antarctica and southern Africa and on a basement of foldbelts terminally deformed at the end of the Devonian (360 Ma) in southern South America and in the mid-Carboniferous (320 Ma) in eastern Australia. With the latest Carboniferous (290 Ma) onset of Pangean extension I, deposition resumed after a lacuna in Gondwanaland with glacigenic sediment. Together with post-Hercynian Europe on the other side of Pangea, postorogenic eastern Australia was subjected to continuing dextral transtension that produced an orocline, related pull-apart basins, and widespread volcanism. At the other end of the Panthalassan margin of Gondwanaland, a new magmatic arc and yoked foreland basin arose in southern South America at about 290 Ma, and by 275 Ma had propagated 4,000 km by migration of a junction of subduction parallel and normal to the margin to reach a point opposite Africa and the Ellsworth Mountains of Antarctica. This (Sakmarian) time saw an ephemeral postglacial marine transgression that flooded much of eastern and southern Australia, the south Atlantic margins of southern Africa and South America, and possibly the Transantarctic basin. The following regression was marked by widespread deposition of coal in all parts of the margin except southern South America. By 265 Ma, the magmatic arc and foreland basin had reached the Bowen Basin in northeastern Australia, and from 258 Ma to the 250 Ma end of the Permian, the foreland basin in Antarctica and Australia subsided rapidly beneath the load of the overthrusting magmatic orogen to accumulate a piedmont of thick tuffaceous coal measures. Both coal and tuff disappeared in Antarctica and Australia at the Permian-Triassic boundary (250 Ma) and were succeeded by barren measures with redbeds, all probably as a result of the global greenhouse warming generated by the eruption of the Siberian Traps. The magmatic arc continued its northward migration, and plutonic activity in eastern Australia continued unabated. The intermittent thrusting of the foldbelt and adjacent foreland basin during the Permian (Gondwanides I) was followed in the mid-Triassic (235–230 Ma) by terminal thrusting along the entire margin (Gondwanides II). Pangean extension II in the Carnian (230 Ma) generated basins in the foldbelt upland, notably in southern South America and eastern Australia, as well as in the sump between the craton and the orogenic upland. Deposition of coal (oil shale in southern South America) resumed after an Early and Middle Triassic gap of 20 million years. The Permian-Triassic (Gondwanan) sedimentary and foldbelt successions were capped in the Jurassic by a flood of silicic volcanics in southern South America and by an even bigger flood of tholeiitic basalt in southern Africa, Antarctica, and Tasmania, and scattered volcanics in southeastern Australia. East Antarctica was rifted from West Antarctica on one side, from Australia on another, and on yet another drifted from Africa by seafloor spreading.