?Microbialites in the Permian-Triassic boundary interval in central China: Structure, age and distribution
?Microbialites in the Permian-Triassic boundary interval in central China: Structure, age and distribution
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DOI：
10.1007/bf02667707
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发表时间：
2002
期刊：
影响因子：
1.8
通讯作者：
S. Kershaw;Li Guo;A. Swift;Jiasong Fan
中科院分区：
文献类型：
--
作者：
S. Kershaw;Li Guo;A. Swift;Jiasong Fan
四川东部二叠纪晚期生物礁复合体的顶部是一个以指状构造为主的碳酸盐结壳。地壳中含有牙形石Hindeodus parvus，确认其年龄为最早的三叠纪;因此，它密切晚于二叠纪末的大规模灭绝，并与相关的古环境变化有关。虽然其分支具有叶状边缘，以及不同标本中放射状组构和叶状组构的内部结构，但由于地壳组构在很大程度上是重结晶的，因此无法确认其有机起源。所以我们用这个词？微生物岩反映其性质的不确定性。在四川南部的贵州省，地壳与已证实的微生物生物层和土丘是同时代的（在小带内）。由工作人员在世界各地的几个地点收集的证据表明，海平面上升发生在边界间隔，这是由四川地壳相证实。在四川东部，由沉淀碳酸盐形成的地壳突然出现和消失，代表了短暂的不寻常的灭绝后海洋条件，这些条件突然打开，然后关闭。在特提斯洋（伊朗和日本）的其他地方，覆盖在P/T边界上的微生物沉积物支持了这种不寻常的海洋条件至少有区域分布的观点。由于地壳突然终止，并没有成功的化石丰富的存款，应用灾害生物群的概念是不合适的;一个环境驱动的控制碳酸盐沉淀更好地支持的证据，无论它是否是生物介导的。
A carbonate crust, with a principally digitate structure, caps latest Permian reef complexes in east Sichuan, China. The crust contains the conodontHindeodus parvus, confirming its age as earliest Triassic; it therefore closely postdates the end-Permian mass extinction, and is related to associated palaeoenvironmental change. Although its branches have lobate margins, and internal structures of radial fabrics and lobate fabrics in different specimens, an organic origin cannot be confirmed, because crust fabric is largely recrystallised. Therefore we apply the term ?microbialite to reflect uncertainty of its nature. The crust is co-eval (within theparvusZone) with confirmed microbial biostromes and mounds in Guizhou Province, south of Sichuan. The sum of evidence, assembled by workers in several sites worldwide, indicates a sea-level rise occurred in the boundary interval, and this is corroborated by facies of the Sichuan crust. Abrupt appearance and disappearance of the crust, formed by precipitated carbonates, in east Sichuan, represents short-lived unusual post-extinction marine conditions which were switched abruptly on, then off. Microbial deposits overlying the P/T boundary in other locations in the Tethys Ocean (Iran and Japan) support the view that the unusual oceanic conditions had at least a regional distribution. Because the crust abruptly terminates, and is not succeeded by fossil-rich deposits, application of the disaster biota concept is inappropriate; an environmentally-driven control on carbonate precipitation is better supported by the evidence, whether or not it was biotically-mediated.