Late Ordovician brachiopod faunal endemism and mass extinction during drastic climate change, ocean anoxia and sea-level fluctuations

剧烈气候变化、海洋缺氧和海平面波动期间奥陶世晚期腕足动物特有现象和大规模灭绝

基本信息

批准号：
RGPIN-2014-04075
负责人：
Jin, Jisuo
金额：
$ 2.19万
依托单位：
University of Western Ontario
依托单位国家：
加拿大
项目类别：
Discovery Grants Program - Individual
财政年份：
2016
资助国家：
加拿大
起止时间：
2016-01-01 至 2017-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=610817
关键词：
Late Ordovician brachiopod faunal endemism

项目摘要

Our concern about global warming today is its effect on sea level rise and biodiversity change. The study of modern global change in climate and biodiversity is confined to the scale of decade to millennium. Paleontologists investigate environmental and biodiversity changes in Earth history at a million-year scale based on fossil record preserved in sedimentary rocks and thus provide unique and valuable data and interpretations to complement studies on modern and recent global change. During the past 530 million years (myr) of the Phanerozoic Earth history, one of the two grandest episodes of global sea-level rises occurred in the Late Ordovician (460–443 myr ago), when much of North America was flooded by epicontinental seas, in which marine life thrived, with brachiopods being the dominant benthic shelly organisms. This was followed by a terminal Ordovician glaciation and mass extinction event. In this proposal, the rich brachiopod fossil record of North America will be studied to determine the responses of Late Ordovician marine benthic shelly faunas to drastic sea level changes. In particular, the following questions will be addressed: 1) How did the continental-margin brachiopod faunas give rise to, and was subsequently replaced by, the epicontinental-sea faunas during the Late Ordovician sea level highstand? 2) Why did the epicontinental brachiopod faunas become highly endemic during the Late Ordovician marine transgression but not during some other similarly high sea-level? and 3) Why did the terminal Ordovician glaciation cause a mass extinction, whereas other major glaciations did not? The approach to these questions is to trace the brachiopod evolution at the species, genus, community, and faunal levels from both continental-margin (e.g. Anticosti Basin, Cincinnati Arch, Mackenzie Mountains) to inland-basin (Hudson Bay, Michigan, and Williston basins) depositional environments through the Late Ordovician sea-level fluctuations, using cladistics, multivariate and other numerical analyses. Results from the proposed research can help us better understand modern global change from the perspective of million year-scale global climate-biodiversity changes in Earth history.

我们今天对全球变暖的关注是它对海平面上升和生物多样性变化的影响，对现代全球气候和生物多样性变化的研究仅限于十年到千年的范围内。年尺度基于沉积岩中保存的化石记录，从而提供独特且有价值的数据和解释，以补充对现代和近期全球变化的研究，这是显生宙地球历史上最伟大的两个事件之一。全球海平面上升的高峰发生在奥陶世晚期（460-443 迈尔前），当时北美大部分地区被陆缘海洋淹没，海洋生物繁盛，腕足动物是主要的底栖有壳生物。在本提案中，将研究北美丰富的腕足动物化石记录，以确定晚奥陶世海洋底栖生物的反应。特别是，将解决以下问题：1）晚奥陶世海平面高位期间，陆缘腕足动物群是如何产生并随后被陆表海动物群所取代的。 2）为什么陆表腕足动物群在奥陶纪晚期海侵期间变得高度流行，但在其他类似的高海平面期间却没有？ 3）为什么奥陶纪末期冰川作用导致了大规模灭绝，而其他主要冰川作用却没有？晚奥陶世沉积环境这项研究的结果可以帮助我们从地球历史上百万年规模的全球气候生物多样性变化的角度更好地理解现代全球变化。