Abstract The Carnian Pluvial Event (CPE) is recorded widely across the Tethys region. Here we present high-resolution carbonate (δ13Ccarb) and organic (δ13Corg) carbon-isotope records and mineral data from the Boli La to lower Bagong formations in the Quemo Co area of the Qiangtang Basin, Qinghai-Tibet Plateau. In this studied section, a calcareous fine-grained sandstone bed that yields a detrital zircon maximum depositional age of 232.5 ± 3.3 Ma, together with ammonoid species and bivalves, allows identification of the Carnian Stage. An intensification of siliciclastic supply and a large drop in calcite and illite is recorded in the Carnian section, suggesting a palaeoclimatic shift from arid to warm and humid during the CPE. A negative carbon-isotope excursion (CIE) in both δ13Corg and δ13Ccarb is also reported, which could be explained by a global perturbation of the carbon cycle and the release of CO2 enriched in 12C. The magnitude of the negative CIE in the Quemo Co area displays a significant shift towards lighter values compared to other reported carbonate carbon-isotope values across the onset of the CPE. A combination of both volcanic emissions from the synchronous Wrangellia large igneous province and release of methane clathrate hydrate is the most likely explanation for the significant negative excursion in δ13C.

中文翻译：

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卡尼期雨洪事件、全球碳循环扰动和火山活动之间可能存在联系：来自青藏高原的新数据

摘要 Carnian 雨洪事件 (CPE) 在整个特提斯地区被广泛记录。在这里，我们展示了青藏高原羌塘盆地却末错地区从勃利拉到八公组下部的高分辨率碳酸盐（δ13Ccarb）和有机（δ13Corg）碳同位素记录和矿物数据。在该研究剖面中，产生碎屑锆石最大沉积年龄为 232.5 ± 3.3 Ma 的钙质细粒砂岩床，连同菊石物种和双壳类动物，可以识别卡尼阶。在 Carnian 剖面记录到硅质碎屑供应的增加和方解石和伊利石的大量减少，表明在 CPE 期间古气候从干旱转向温暖和潮湿。还报告了 δ13Corg 和 δ13Ccarb 中的负碳同位素偏移 (CIE)，这可以通过碳循环的全球扰动和富含 12C 的 CO2 的释放来解释。与其他报道的碳酸盐碳同位素值相比，在 CPE 开始时，Quemo Co 地区负 CIE 的幅度显示出向更轻值的显着转变。来自同步 Wrangellia 大型火成岩省的火山排放和甲烷笼形水合物释放的组合是 δ13C 显着负偏移的最可能解释。