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A complete marine uppermost Permian to Lower Triassic succession is well exposed at the Daxiakou section of the Three Gorges area, western Hubei Province, South China. A total of 12 conodont zones are recognized from the uppermost Changhsingian (upper Permian) to Olenekian (Lower Triassic). Of these, the Clarkina yini, Clarkina meishanensis, and Clarkina taylorae Zones characterize the uppermost Changhsingian, whereas the Hindeodus parvus, Isarcicella staeschei, Isarcicella isarcica, Neoclarkina krystyni, Neoclarkina discreta, Sweetospathodus kummeli, and Neospathodus dieneri Zones define the Induan. Early Olenekian conodonts are assignable to the Novispathodus waageni and Nv. pingdingshanensis Zones. Conodont zones across the Permian-Triassic boundary (PTB) beds at Daxiakou correlate well with those established from the Meishan section, the Global Stratotype Section and Point (GSSP) for the PTB. The PTB is placed at the base of Bed 11c at Daxiakou. The Ns. dieneri M1, Ns. dieneri M2, and Ns. die...

Microbialite masses within the lowest Triassic strata along the southern periphery of the tropical Yangtze Platform were produced in a post-Permian microbial regime. These microbialites (the Hindeodus parvus Zone), which are represented by thrombolites, occur only where terrigenous sediment influx was rare, even in shallow-marine settings. The lower parts of the thrombolites lie upon a distinctly unconformable Permian-Triassic boundary and exhibit a thin-bedded to thick-bedded planar structure. In contrast, the upper parts of the thrombolites contain domed macrostructures that interact in complex ways with skeletal grainstones and packstones. Irregular frameworks of thrombolite bodies differ in degree of lateral and vertical accumulation and in the amalgamation of mesoclots of microbial origin; they exhibit marked variations in texture. A transgressive episode occurred in the earliest Triassic following the mass extinctions, and this included the initiation of microbial regimes that usually forme...

The end-Permian extinction reflects one of the greatest biotic crises in earth history. Evidence of the event and its aftermath is well preserved in Permian/Triassic transitional strata of Sichuan Province in South China, originally deposited in the western part of the Yangtze epicontinental sea. Lowest Triassic strata (the Hindeodus parvus conodont Zone) lie with apparent conformity on uppermost Permian skeletal packstone and wackestone, and are overlain by deeper subtidal thinly bedded argillaceous lime mudstone. These beds are characterized by thrombolitic mesostructures that exhibit macrostructures of highly variable columnar shapes, showing a distinctive stratigraphic succession in bed form from planar to domed and subspherical forms. Spheroidal and ellipsoidal micritic bodies (30 µm in average diameter) are preserved in clusters and are interpreted as calcified coccoidal microbes. The earliest Triassic thrombolitic columns and masses are considered to have been constructed by vertical and l...

Permian-Triassic boundary (PTB) sections from isolated carbonate platforms in the Nanpanjiang Basin of south China contain Upper Permian skeletal packstones with diverse open-marine fossils overlain by a 7–15 m thick boundary horizon composed of calcimicrobial framestone constructed by globular to tufted, calcified cyanobacteria similar to Renalcis. The framestone contains interbeds of lime-grainstone with abundant thin-shelled bivalves and brachiopods. The overlying Lower Triassic strata contain microgastropod lime-packstones followed by a thick succession of thin-bedded lime-mudstones. The PTB event horizon is interpreted to occur at the top of the packstone containing diverse, open-marine fauna and Palaeofusulina and coincident with the abrupt change to calcimicrobial framestone lacking Permian macrofossils. The conformable biostratigraphic boundary occurs at the first appearance of Hindeodus parvus within the basal meter of the calcimicrobial framestone. Intensively studied PTB sections in so...