The Middle Triassic is regarded as an important period of biotic recovery after the end-Permian mass extinction, of which the Middle Triassic Luoping biota represents a full recovery of marine ecosystem. However, the research on the relationship between biotic recovery and environmental evolution in the Middle Triassic remains poorly understood. To investigate this issue, microfacies analysis and multiple geochemical proxies (Al, Ti, Th, Sc, and ∑REY) of an Anisian (Middle Triassic) succession (the Member II of the Guanling Formation, Leniduo section, South China) yielding the Luoping biota are carried out. Five sedimentary facies are identified through field investigation and microfacies analysis: open platform, restricted platform, tidal flat, shoal and intra-platform depression. According to the changes of multiple geochemical proxies, this section can be divided into five stages. A sudden facies transition from open platform to intra-platform depression, and high contents of Al, Ti, Sc, Th, and ∑REY in stage IV indicate a rapid sea-level rise and detrital input increase, coinciding with the preservation of the Luoping biota. This evidence suggest that enhanced continental weathering caused by global warming, global sea level rise, and frequent regional volcanic activities promoted the death and preservation of the Luoping biota.

中文翻译：

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华南中三叠统关岭组古气候演化及其对罗平生物群保存的意义


中三叠世被认为是二叠纪末大灭绝后生物恢复的重要时期，其中中三叠世罗平生物群代表了海洋生态系统的全面恢复。然而，对中三叠世生物恢复与环境演变之间关系的研究仍然知之甚少。为了研究这个问题，对产生罗平生物群的异一统（中三叠世）演替（华南地区乐尼多段关岭组二段）进行了微相分析和多个地球化学代理（Al、Ti、Th、Sc 和 ∑REY）。通过野外调查和微相分析确定了 5 种沉积相：开放平台、限制平台、潮滩、浅滩和平台内洼地。根据多个地球化学代理的变化，本节可分为五个阶段。从开阔平台向平台内凹陷的突然相转变，以及 IV 期 Al、Ti、Sc、Th 和 ∑REY 的高含量表明海平面快速上升和碎屑输入增加，与罗平生物群的保存相吻合。这一证据表明，全球变暖、全球海平面上升和频繁的区域火山活动引起的大陆风化增强促进了罗平生物群的死亡和保存。