Integrated biochemostratigraphy of the Permian-Triassic boundary beds in a shallow carbonate platform setting (Yangou, South China)
Integrated biochemostratigraphy of the Permian-Triassic boundary beds in a shallow carbonate platform setting (Yangou, South China)
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DOI：
10.1016/j.gloplacha.2021.103583
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发表时间：
2021-07
影响因子：
3.9
通讯作者：
He Zhao;Zhengyi Lyu;Zhong‐Qiang Chen;T. Algeo;M. Orchard;Yongsheng Liu;Zhaochu Hu;Lei Zhang
中科院分区：
文献类型：
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作者：
He Zhao;Zhengyi Lyu;Zhong‐Qiang Chen;T. Algeo;M. Orchard;Yongsheng Liu;Zhaochu Hu;Lei Zhang
高分辨率牙形石生物地层学研究极大地促进了二叠纪末生物大灭绝（EPME）的研究。然而，到目前为止，详细的生物地层框架一直缺乏浅海继承的特提斯区域。在目前的研究中，我们分析了碳酸盐微相，牙形石生物地层学和碳酸盐碳同位素的岩沟采石场部分，一个浅海EPME序列，积累了一个孤立的碳酸盐银行上的北方边缘的扬子地台。微相分析产生了4个相和8个微相，记录了海水加深后立即EPME。在EPME和最早的三叠纪生物大灭绝（ETME）期间，大量产生了Ooids，但在最早的三叠纪海侵期间被微生物垫，藻类，双壳类和腕足动物所取代。从长兴阶最上阶到格里斯巴赫阶最下阶，自下而上划分出三个牙形石带：Hindeodus praeparvus带、H. parvusZone和IsarcicellastaescheiZone. EPME和PTB（二叠-三叠系界线）层位以H的首次出现为标志。praeparvusat 6.18m和H. parvusat 6.57米，分别高于该部分的基础。通过对岩沟采石场剖面的δ 13 C碳剖面进行对比，建立了牙形石生物地层格架。该剖面记录了与EPME和ETME层位相关的两个离散的负碳同位素偏移（CIE），并且可以与梅山D和全球其他PTB剖面的类似CIE相关联。我们的研究提供了第一个综合的，高分辨率的生物化学地层框架的浅海PTB继承在东特提斯地区，这将有利于古环境研究类似的相在其他地方，以及与深水相的相关性。
Investigation of the end-Permian mass extinction (EPME) has been greatly facilitated by high-resolution conodont biostratigraphic studies. To date, however, a detailed biostratigraphic framework has been lacking for shallow-marine successions of the Tethys region. In the present study, we analyzed carbonate microfacies, conodont biostratigraphy, and carbonate carbon isotopes of the Yangou Quarry section, a shallow-marine EPME succession that accumulated on an isolated carbonate bank on the northern margin of the Yangtze Platform. Microfacies analysis yielded four facies and 8 microfacies that record a seawater deepening immediately following the EPME. Ooids were abundantly produced during the EPME and earliest Triassic mass extinction (ETME) but were replaced by microbial mats, algae, bivalves, and brachiopods during an earliest Triassic transgression. A total of three conodont zones are recognized from the uppermost Changhsingian to the lowermost Griesbachian, in ascending order, theHindeodus praeparvusZone,H. parvusZone, andIsarcicella staescheiZone. The EPME and PTB (Permian-Triassic boundary) horizons are marked by the first occurrences ofH. praeparvusat 6.18 m andH. parvusat 6.57 m, respectively, above the base of the section. The conodont biostratigraphic framework of the Yangou Quarry section was refined through intercalibration with its δ13Ccarbprofile. This section records two discrete negative carbon isotope excursions (CIEs) that are correlative with the EPME and ETME horizons, and that can be correlated with similar CIEs at Meishan D and other PTB sections globally. Our study provides the first integrated, high-resolution biochemostratigraphic framework for a shallow-marine PTB succession in the eastern Tethys region, which will facilitate paleoenvironmental studies of similar facies elsewhere as well as correlations with deeper-water facies.