The Beginning of the Mesozoic: Paleoecological and Paleo- environmental Analysis of the Lower Triassac Virgin Limestones (Nevada and Utah)

中生代的开始：下三叠纪原始石灰岩（内华达州和犹他州）的古生态和古环境分析

基本信息

批准号：
9004547
负责人：
David Bottjer
金额：
$ 9万
依托单位：
University of Southern California
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
1990
资助国家：
美国
起止时间：
1990-07-01 至 1993-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9004547&HistoricalAwards=false
关键词：
Beginning Mesozoic Paleoecological Paleo environmental

项目摘要

The mass extinction at the end of the Permian has been established as the greatest perturbation which the Earth's biosphere has experienced since the origin of metazoan life. Although relatively little is known about the cause of this mass extinction, even less is known on biotic conditions in its aftermath or the nature of biotic recovery from this event. Fossil faunas and limestones in the Lower Triassic Virgin Member of the Moenkopi Formation (southern Nevada and southwestern Utah), deposited 5 my after the end of the Permian, present an opportunity to learn how benthic faunas in shallow marine carbonate environments were faring in this recovery interval. Preliminary study of the Virgin limestones indicates deposition in a normal marine environment with benthic macroinvertebrate assemblages of relatively low species richness. Of potentially great significance are intervals of apparent normal marine stromatolites, which may represent temporary expansion from marginal marine refugia into normal marine settings due to restriction of grazers, caused by the mass extinction. Evidence for the beginning of recovery is demonstrated through the presence of abundant specimens of the earliest articulate crinoid, which had evolved from some unknown Paleozoic inadunate that survived the crisis. Research will illuminate the way in which biotas recover from mass extinctions.

二叠纪末端的质量灭绝已被确定为自后生动物生命起源以来地球生物圈所经历的最大扰动。尽管对这种质量灭绝的原因的了解相对较少，但在此事件中生物恢复的性质或生物恢复的性质中，在生物条件下甚至更少。 Moenkopi组的下三叠纪处女成员（内华达州南部和犹他州西南部）的化石动物和石灰石，存放了5我的二叠纪之后，这是一个机会，有机会学习在浅水碳酸盐环境中如何学习这种恢复的底栖动物间隔。对维珍石灰岩的初步研究表明在正常的海洋环境中沉积，底栖大型无脊椎动物组合的物种丰富度相对较低。潜在的重要性是明显正常海洋基质石的间隔，这可能代表了由于质量灭绝而导致的局限性，这可能代表从边缘海洋避难所暂时扩张到正常海洋环境中。通过最早的表达性链球菌的大量标本的存在证明了开始恢复的证据，这些标本是从某种未知的古生代非载体中进化而来的，这些古生代在危机中幸存下来。研究将阐明生物群体从大规模灭绝中恢复的方式。