Extinction and Recovery of Crinoids Resulting from Climatic Change during the Ordovician-Silurian Biotic Crisis

棘皮动物门是整个古生代(约5.7亿至2.65亿年前)最重要的海洋生物之一。它们在维持古生代群落的生态结构、棘皮动物的多样性和丰富性以及作为沉积物贡献者的重要性方面占主导地位，最终导致了今天的石灰岩。然而，奥陶纪末期的全球环境变化导致了海百合的大规模灭绝，并最终导致了海百合的宏观进化重组，因为它们在早志留纪多样化。奥陶纪末期的环境变化是由于南部古大陆的大陆冰川作用导致的全球降温和海平面下降造成的。对奥陶纪末期生物危机的透彻理解将提供一个重要的例子，说明全球环境变化在深层次上的后果，以便将最近发生的全球环境变化与最近发生的全球环境变化进行比较，并预测全球环境变化未来的海洋影响。这项提议的目标如下。1)奥陶系-志留系界线附近地层，即埃利斯湾组和贝塞西组的海百合化石的野外采集和研究。2)收集用于同位素分析的样品将与我们的加拿大同事的工作相协调，以便尽可能透彻地了解这些地层剖面。该计划是对同位素尚不清楚的阿什吉利亚沃雷亚组进行采样，并在岛东部未采样部分跨越O-S边界的地层中进行采样。3)在可用时间内，整合两个数据集，以进一步了解安提科里岛奥陶系-志留系序列是否完整，或是否存在可能影响拟议研究目标的准整合面。4)通过实地考察、实验室研究和准备论文(本科生和研究生)，为本科生和研究生提供研究性学习体验。

Crinoids (Phylum Echinodermata) were among the most important marine organisms throughout the Paleozoic (ca 570 to 265 million years ago). They were dominant in maintaining the ecological structure Paleozoic communities, in diversity and abundance among echinoderms, and in importance as sediment contributors that ultimately led to the limestones of today. However, end-Ordovician global environmental change resulted in a mass extinction of crinoids and, ultimately, a macroevolutionary reorganization of crinoids as they diversified during the Early Silurian. End-Ordovician environmental change was caused by global cooling and sea level lowering resulting from a continental glaciation on the southern paleocontinents. A thorough understanding of the end-Ordovician biotic crisis will provide an important example of the consequences of global environmental change in deep time against which to compare global environmental changes that have occurred in the most recent past and for predicting future oceanic impacts of global environmental change. The objectives of this proposal are the following. 1) Field collection and study of crinoids in strata immediately surrounding the Ordovician-Silurian boundary, i.e. the Ellis Bay and Becscie formations. 2) Collection of samples for isotopic analysis will be coordinated with work by our Canadian colleagues in order to develop as thorough an understanding as possible of these stratigraphic sections. The plan is to sample the Ashgillian Vaureal Formation, for which isotopes are not known, and to take samples in formations that span the O-S boundary in unsampled sections in the eastern part of the island. 3) Within the time available, integrate the two data sets to further develop an understanding of whether the Anticosti Island Ordovician-Silurian succession is complete or whether there are paraconformities present that would affect the objectives of the study being proposed. and 4) provide a research learning experience for undergraduate and graduate students through field studies, laboratory research, and preparation of theses (undergraduate and graduate).