The Permian-Triassic transition in ocean island setting: Environmental disturbances and new high-resolution carbon-isotope record from the Qiangtang Basin, NW China

摘要: Abstract The Permian-Triassic boundary (PTB) events such as carbon-isotope excursion, volcanism, and environmental disturbances are not well understood in an ocean island setting. Here, we develop a new case study for the transition Qiangtang Basin, Tibet, by combining existing biostratigraphy, data, sedimentological U Pb zircon age, mineralogical geochemical data. These data defined age about 252.3 ± 0.9 Ma, corresponding to lowermost sea level. A long-term negative carbonate carbon isotope trend is present at same stratigraphic level different depositional environments, strongly suggesting its global nature. However, our setting characterized abrupt shift values across level, which from many chemostrtigraphic studies that show gradual event horizon. most likely explanation δ13C sedimentary hiatus this section. Three-stage climatic models through PTB identified: Stage 1 warm humid climate with moderate chemical weathering; while hot intense weathering dominates stage 2; 3 relatively arid condition weak weathering.