Ordovician-Silurian graptolites, integrated stratigraphy, biodiversity history, and paleoenvironmental change

奥陶纪-志留纪笔石、综合地层学、生物多样性历史和古环境变化

• 批准号: RGPIN-2018-05397
• 负责人: Melchin, Michael
• 金额: $ 2.62万
• 依托单位: St. Francis Xavier University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=659508
• 关键词: Ordovician; Silurian; graptolites; integrated; stratigraphy

** p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px 'Times New Roman'}**** p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px 'Times New Roman'}******* p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px 'Times New Roman'}******* p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px 'Times New Roman'}******* * 0* 0* 1* 382* 2179* STFX* 18* 5* 2556* 14.0* * * * *** * Normal* 0* * * * * false* false* false* * EN-CA* X-NONE* X-NONE* * * * * * * * * * * * * * * * * * * * * * * * ** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *** **** /* Style Definitions */*table.MsoNormalTable* {mso-style-name:"Table Normal";* mso-tstyle-rowband-size:0;* mso-tstyle-colband-size:0;* mso-style-noshow:yes;* mso-style-priority:99;* mso-style-parent:"";* mso-padding-alt:0cm 5.4pt 0cm 5.4pt;* mso-para-margin:0cm;* mso-para-margin-bottom:.0001pt;* mso-pagination:widow-orphan;* font-size:10.0pt;* font-family:"Times New Roman";}*******The Ordovician and Silurian periods (ca. 500-420 million years ago) were*times of dramatically changing climate, sea level, and biodiversity. One of the*biggest mass extinction events in Earth history occurred near the end of the*Ordovician Period. The most important group of animals preserved in the marine*plankton during these time periods was the graptolites, a group of mostly*extinct hemichordates. They were abundant, geographically widespread and*evolved rapidly, which makes them excellent fossils for identifying short*intervals of geologic time and correlation of those intervals around the globe.*A thorough understanding of these organisms and their distribution in*sedimentary strata maximizes our potential to use them to solve a wide range of*Earth science problems in areas such as tectonics, sedimentary basin history,*climate change, and long-term evolution of the world's oceans. My research*program has several major and ongoing objectives: 1) reconstruction of the*evolutionary history of graptolites; 2) understanding the history of change of*graptolite biodiversity as a result of changing rates of species origination*and extinction, particularly through the cycles of climatic and oceanic changes*that characterized the Ordovician and Silurian periods; and 3) studying the*physical and chemical record preserved in rock strata to better understand the*environmental cycles and their causes, particularly to gain insights into the*factors responsible for the Late Ordovician Mass Extinction. For the last objective,*I am particularly interested in the history of anoxia in the oceans – times*when large areas of the ocean became depleted in oxygen. I propose to examine*oceanic anoxia using sedimentary, paleontological and geochemical signals, and*investigate the formation and changing distribution of anoxia in terms of its*relationship to changes in climate, ocean circulation and biological*productivity. I will also integrate data from graptolite occurrences with the*geochemical record in sedimentary strata from several different parts of the*world to improve the precision with which we can define and subdivide*geological time. By improving the precision with which we can resolve*geological time, we can gain clearer insights into the timing and rates of*evolutionary, paleoenvironmental and geological processes. This research into*the long-term links among climate change, ocean circulation and biodiversity*will provide insights that will help us better understand the modern world of*changing climate and biodiversity.*** ** p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px

**p.p1{页边距：0.0px 0.0px 0.0px；字体：12.0px‘Times New Roman’}*p.p1{页边距：0.0px 0.0px 0.0px；font：12.0px‘Times New Roman’}*p.p1{页边距：0.0px 0.0px 0.0px；字体：12.0px‘Times New Roman’}*p.p1{页边距：0.0px 0.0px 0.0px；字体：14.0px‘Times New Roman’}***0*0*1*382*2179*StFX*18*5*2556*14.0***普通*0***FALSE**en-CA*X-NONE*X-NONE*******mso-tstyle-rowband-size：0；*mso-tstyle-colband-size：0；*mso-style-noshow：是；*mso-style-first：99；*mso-style-parent：“”；*mso-pding-alt：0 cm 5.4pt 0 cm 5.4pt；*mso-para-mark：0 cm；*mso-para-space-Bottom：.0001pt；*mso-Page：寡妇-孤儿；*字体大小：10.0pt；*font-family：“Times New Roman”；奥陶纪和志留纪(约500-4.2亿年前)是气候、海平面和生物多样性急剧变化的时代。地球历史上最大的物种灭绝事件之一发生在奥陶纪末期。在这些时期，在海洋浮游生物中保存下来的最重要的一类动物是笔石，这是一群几乎已经灭绝的半角类动物。它们数量丰富，地理分布广泛，演化迅速，这使它们成为识别短地质时间间隔和全球这些时间间隔对比的极佳化石。*彻底了解这些生物及其在沉积地层中的分布，将使我们最大限度地利用它们来解决构造、沉积盆地历史、气候变化和世界海洋长期演化等领域的广泛地球科学问题。我的研究计划有几个主要和持续的目标：1)重建笔石的*进化史；2)了解由于物种起源和灭绝速度的变化而导致的笔石生物多样性的变化历史，特别是通过以奥陶纪和志留纪为特征的气候和海洋变化周期；以及3)研究保存在岩层中的*物理和化学记录，以更好地了解*环境周期及其原因，特别是深入了解导致奥陶纪晚期大灭绝的*因素。对于最后一个目标，我特别感兴趣的是海洋中的缺氧史--海洋大片区域耗尽氧气的时代。我建议使用沉积、古生物和地球化学信号来研究海洋缺氧，并根据其与气候、海洋环流和生物生产力变化的关系来调查缺氧的形成和变化的分布。我还将把笔石产状的数据与世界上几个不同地区的沉积地层中的地球化学记录结合起来，以提高我们定义和细分地质时间的精度。通过提高我们可以解析地质时间的精度，我们可以更清楚地了解进化、古环境和地质过程的时间和速率。这项对气候变化、海洋环流和生物多样性之间的长期联系的研究将提供见解，帮助我们更好地理解气候和生物多样性变化的现代世界。