Biostratigraphy, Paleoceanography, and Community Dynamics of Siliceous Microfossils from the Silurian of the Canadian Arctic

加拿大北极地区志留纪硅质微化石的生物地层学、古海洋学和群落动态

• 批准号: 9972845
• 负责人: Paula Noble
• 金额: $ 0.4万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-10-01 至 2000-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9972845&HistoricalAwards=false
• 关键词: Biostratigraphy; Paleoceanography; Community; Dynamics; Siliceous

9972845Noble This study will fund the collection of geochemical and micropaleontological samples from the Silurian Cape Phillips Fm., Canadian Arctic. It is part of a coordinated effort between U. S. and Canadian workers to extract the maximum amount of data from important and remote sections that can later be synthesized to produce a comprehensive story of the shelf margin history from Later Ordovician-early Devonian time. The data collection in this project will address three specific problems:1. Biostratigraphic tool development-The investigator has been working towards developing a biostratigraphic scheme for Ordovician-Silurian radiolarians, but lacks independent age control on Late Silurian sections. The Cape Phillips Fm. has the best preserved Silurian radiolarians in the world, it is age is well constrained by graptolites, and it has the best possibility of providing the age control needed. 2. Extinction/diversification events- Radiolarian response will be examined across two mid Silurian graptolite extinctions and subsequent diversifications. Total organic Carbon, carbon isotope analysis of whole-rock inorganic and organic carbon, and elemental analysis of the non-carbonate fraction will be conducted across the extinction's to look for related geochemical signatures.3. Siliceous spicules in paleoecology-The percentage of lithistid to hexactinellid spicules has previously been observed to vary with sea level rise in Late Ordovician sections. Spicules will be examined in conjunction with the physical stratigraphy in order to test their sensitivity to local sea-level fluctuation. These data will be tied into changes observed in the plankton community and the basin history.

9972845值得注意的是，这项研究将资助从加拿大北极的志留纪菲利普斯角采集地球化学和微古生物样本。这是美国和加拿大工作人员共同努力的一部分，目的是从重要的和偏远的剖面中提取最大量的数据，这些数据稍后可以被合成，以产生奥陶纪晚期-泥盆纪早期陆架边缘历史的全面故事。该项目的数据收集将解决三个具体问题：1.生物地层学工具的开发--调查者一直致力于开发奥陶系-志留纪放射虫的生物地层学方案，但缺乏对晚志留纪剖面的独立年龄控制。菲利普斯角调频公司。拥有世界上保存最完好的志留纪放射虫，它的年龄受到笔石的很好限制，它具有提供所需年龄控制的最佳可能性。2.灭绝/多样化事件--将通过两次中志留世笔石灭绝和随后的多样化来研究放射虫的反应。将进行总有机碳、全岩无机碳和有机碳的碳同位素分析，以及非碳酸盐部分的元素分析，以寻找相关的地球化学标志。古生态中的硅质针状体-在晚奥陶世剖面中，石类与六角形针状体的比例以前被观察到随着海平面的上升而变化。针状物将结合物理地层学进行检查，以测试它们对局部海平面波动的敏感性。这些数据将与在浮游生物群落和盆地历史中观察到的变化联系在一起。