Rapid marine recovery after the end-Permian mass-extinction event in the absence of marine anoxia
Rapid marine recovery after the end-Permian mass-extinction event in the absence of marine anoxia
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DOI：
10.1130/g20585.1
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发表时间：
2004-09
期刊：
影响因子：
5.8
通讯作者：
R. Twitchett;L. Krystyn;A. Baud;J. Wheeley;S. Richoz
中科院分区：
文献类型：
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作者：
R. Twitchett;L. Krystyn;A. Baud;J. Wheeley;S. Richoz
本文描述了阿曼中部山脉一处早三叠世的新海洋动物群。根据丰富的牙形石和菊石判断，该动物群年代为格里斯巴赫期，沉积于阿拉伯地台边缘一处富氧的海山环境中。这是首个来自富氧海洋环境的格里斯巴赫期动物组合，因而为“广泛缺氧阻碍了生物快速复苏”这一假说提供了检验依据。格里斯巴赫早期（parvus带）的底栖动物群多样性较低，以双壳类的前直肌蛤（Promyalina）和克氏蛤（Claraia）为主。全球范围内，紧接灭绝事件之后的时期都呈现出类似程度的复苏特征。然而，格里斯巴赫中晚期的沉积岩（isarcica带和carinata带）中，包含了种类极为丰富的底栖动物群，有双壳类、腹足类、有铰腕足类、一种尚未描述的海百合、海胆以及介形虫。与全球缺氧环境中所描述的典型格里斯巴赫中晚期动物群相比，该动物群的多样性更高，生态结构也更为复杂。在其他地区，直到斯帕斯期才出现阿曼动物群所呈现的灭绝后复苏程度。这些数据支持了这样一种假说，即二叠纪末灭绝事件后生物复苏明显延迟，是由于广泛且长期的底栖缺氧：在不存在缺氧的情况下，海洋生物的复苏要快得多。
A new Early Triassic marine fauna is described from the Central Oman Mountains. The fauna is Griesbachian in age, on the basis of abundant conodonts and ammonoids, and was deposited in an oxygenated seamount setting off the Arabian platform margin. It is the first Griesbachian assemblage from a well-oxygenated marine setting and thus provides a test for the hypothesis that widespread anoxia prevented rapid recovery. The earliest Griesbachian (parvus zone) contains a low-diversity benthic fauna dominated by the bivalves Promyalina and Claraia. A similar level of recovery characterizes the immediate postextinction interval worldwide. However, the middle upper Griesbachian sedimentary rocks (isarcica and carinata zones) contain an incredibly diverse benthic fauna of bivalves, gastropods, articulate brachiopods, a new undescribed crinoid, echinoids, and ostracods. This fauna is more diverse and ecologically complex than the typical middle to late Griesbachian faunas described from oxygen-restricted settings worldwide. The level of postextinction recovery observed in the Oman fauna is not recorded elsewhere until the Spathian. These data support the hypothesis that the apparent delay in recovery after the end-Permian extinction event was due to widespread and prolonged benthic oxygen restriction: in the absence of anoxia, marine recovery is much faster.