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 {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;字体：14.0px 'Times New Roman'}* * 0* 0* 1* 382* 2179* STFX* 18* 5* 2556* 14.0* 普通 * 0 * false * false * EN-CA* X-无 * X-无 * * * * * * * * * * * * * * * * * * * * * * * * ** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *** * /* 样式定义 */*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”;奥陶纪和志留纪（Ordovician and Silurian）5亿~ 4.2亿年前）是气候、海平面和生物多样性急剧变化的时期。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，海洋浮游生物中保存下来的最重要的动物群是笔石，一群几乎灭绝的半索动物。它们数量丰富，地理分布广泛，进化迅速，这使它们成为识别地质时间短间隔和地球仪相关性的绝佳化石。深入了解这些生物及其在沉积地层中的分布，将最大限度地发挥我们的潜力，利用它们来解决诸如构造、沉积盆地历史、气候变化和世界海洋长期演变等领域的广泛的地球科学问题。我的研究计划有几个主要的和正在进行的目标：1）重建笔石的进化历史; 2）理解笔石生物多样性的变化历史，这是物种起源和灭绝的变化率的结果，特别是通过奥陶纪和志留纪时期的气候和海洋变化的周期;研究保存在岩层中的物理和化学记录，以更好地了解环境循环及其原因，特别是了解导致晚奥陶世大灭绝的因素。对于最后一个目标，* 我对海洋缺氧的历史特别感兴趣-当海洋的大面积缺氧时。我建议用沉积学、古生物学和地球化学信号来研究海洋缺氧，并从缺氧与气候变化、海洋环流和生物生产力的关系方面来研究缺氧的形成和变化分布。我还将把笔石出现的数据与世界上几个不同地区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。通过提高我们对地质时间的精确度，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度。这项对气候变化、海洋环流和生物多样性之间长期联系的研究将提供深入的见解，帮助我们更好地了解气候变化和生物多样性的现代世界。** p.p1 {页边距：0.0px 0.0px 0.0px 0.0px;字体：12.0px