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The Late Paleozoic Taiyuan Formation in North China is mainly composed of a mixed shallow-marine carbonate and terrigenous clastic deposits. Its basal limestones have been constrained in the late Pennsylvanian to Early Permian. To further constrain the age of the lowest Taiyuan Formation, we obtained two genera and 16 species of conodonts from the bottom limestones of the Taiyuan Formation in two sections in Henan Province, southern North China. The fauna includes Idiognathodus hebeiensis, Streptognathodus isolatus, S. elongatus, S. cf. longus, S. acuminatus, S. cf. recreatus, S. cf. cristellaris, S. bellus, S. invaginatus, S. wabaunsensis, S. glenisteri, S. conjunctus, S. binodosus, S. fuchengensis, S. nodulinearis, and S. sp. A genus of Streptognathodus dominated conodont assemblage with some Idiognathodus elements. It indicates a late Gzhelian (latest Pennsylvanian) age for the lowest Taiyuan Formation in southern North China. This is consistent with recently published high-precision zircon U-Pb ages from ash layers. Based on conodont biostratigraphy, the basal limestones of the Taiyuan Formation in Henan Province (southern North China) can be correlated with the upper part of Miaogou limestones of the Taiyuan Formation in Shanxi Province (northern North China). This correlation might reflect a significant sea-level rise in North China, possibly corresponding to a deglaciation event at the Permo-Carboniferous transition. [ABSTRACT FROM AUTHOR]

The Carboniferous-Permian transition is a critical period for the Late Paleozoic Ice Age that evolved from an acme to the subsequent demise with the initiation of long-term drying in low latitudes. During this time interval, extensive epicontinental deposition occurred in North China in the eastern tropical Tethyan region, and archived important information of climate and sea-level changes. Though several high-precision zircon U Pb ages have been reported, they have some conflicts with previously defined biostratigraphic correlations, especially for the Taiyuan Formation. Lack of high-resolution conodont biostratigraphy has impeded the correlation with other well-studied Pangean records. In this study, five conodont zones were established for the successions of the Taiyuan Formation in southern North China. They are Streptognathodus wabaunsensis , S. isolatus , S. sigmoidalis , S. constrictus and S. fusus biozones in ascending order, constraining a late Gzhelian to late Asselian age for the Taiyuan Formation in southern North China, which is consistent with published high-precision zircon U Pb ages. The Unitary Association (UA) analysis was used to reconcile the conodont biostratigraphy of the Taiyuan Formation in North China, and was combined with previously published high-precision U Pb ages to construct a new chronostratigraphic framework for the Carboniferous-Permian strata across North China. It explicitly indicates an earlier initiation of climate aridification in the northern part than in the southern part of North China possibly due to northward drift and/or increased atmospheric p CO 2 and associated global warming. • Conodont biostratigraphy is updated for the Taiyuan Formation in North China. • The age of Taiyuan Formation is constrained in the late Gzhelian to late Asselian. • An Early Permian north-to-south climate drying trend is indicated for North China. [ABSTRACT FROM AUTHOR]

Continual deep-water sediments from the late Early Devonian to the Late Permian extended in wide areas of western Guangxi. We analyzed the major, trace, and rare earth elements of the Upper Paleozoic cherts in Badu, western Guangxi. High non-terrigenous SiO contents (Si/Si(%)> 80%) and pure chert components (> 70%) indicate a large extent of silicification in the Upper Paleozoic cherts, except for the Upper Devonian-Lower Carboniferous Luzhai Formation cherts, which have lower non-terrigenous SiO contents (avg. 71.8%) and pure chert components (40%-70%). The Al/(Al+Fe+Mn) ratios and Feter/Fe(%) values of samples from the lowest horizon of the Pingen Formation are 0.05-0.26, 13.1%-14.5%, respectively, indicating hydrothermal origins. All other samples show high Al/(Al+Fe+Mn) ratios (0.39-0.81) and high Feter/Febulk(%) values (23.1%-186.8%), indicating non-hydrothermal origins. The Pingen Formation and Liujiang Formation cherts show slightly-moderately negative Ce anomalies (0.71±0.07, 0.81±0.08, respectively) and higher Y/Ho ratios (33.49±1.27, 36.10±2.05, respectively) than PAAS. This suggests that these cherts were deposited in the open marine basin, rather than in the intracontinental rift basin as previously assumed. The Luzhai Formation cherts may be deposited near the seamount or seafloor plateaus with no negative Ce anomalies (1.09±0.07) and no significant Y-Ho fractionation (Y/Ho=28.60±1.25). The Nandan Formation and Sidazhai Formation cherts were deposited in the open-ocean basin with moderately negative Ce anomalies (0.67±0.08, 0.73±0.11, respectively) and high Y/Ho ratios (36.01±1.00, 32.00±2.25, respectively). On the basis of our studies about cherts, we conclude that the Youjiang Basin originated as part of the Paleo-Tethys that controlled the depositional environments of cherts during late Paleozoic. The rift of the Youjiang Basin had occurred at least since the Early-Middle Devonian. The basin had a trend of evolving into an open-ocean basin during the Early-Middle Permian. [ABSTRACT FROM AUTHOR]

Abstract: Unconformity bound Permo-Triassic successions in the Qinfang Basin, South China Craton, reflect tectonic processes associated with tectonothermal activity along the margins of the craton. The provenance record of these successions, based on modal analysis, geochemical composition, detrital zircon U–Pb ages, and paleocurrent data indicate derivation from the adjoining Precambrian Yunkai massif and surrounding Paleozoic sedimentary units. The quartz dominated nature of the siliciclastic units, along with their high Th/Sc and Zr/Sc ratios indicate a recycled orogen source. Detrital zircons from Late Permian to Early Triassic samples display major age groups at 1100–800Ma, 650–500Ma, 480–420Ma, with subordinate age groups at 2800–2400Ma, 1900–1600Ma and 1400–1200Ma. Late Triassic sandstones show a similar detrital zircon age pattern as well as a 300–250Ma age group. Integration of this provenance data with regional geological information suggests that the unconformity at the base of the Permian succession is related to subduction of the Paleo-Tethys ocean to the south of the craton, whereas the major driver for Triassic tectonic activity corresponds with terrane accretion and the termination of Paleo-Tethys Ocean subduction along the southwest margin of the craton. [Copyright &y& Elsevier]