High-Resolution Chronostratigraphic Constraints on the Biogeography of New Tetrapod Assemblages from Triassic Paleoequatorial Rift Basins of Southeastern North America

北美东南部三叠纪古赤道裂谷盆地新四足动物组合生物地理学的高分辨率年代地层约束

• 批准号: 0087634
• 负责人: Paul Olsen
• 金额: $ 13.38万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-15 至 2004-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0087634&HistoricalAwards=false
• 关键词: Resolution; Chronostratigraphic; Constraints; Biogeography; New

The objective of this project is to develop a high-resolution chronologic, stratigraphic, and paleogeographic framework for the southernmost exposed Triassic rift basins in eastern North America, specifically the Deep River and Dan River basins and to a lesser extent, the Richmond, and Taylorsville basins. These basins comprise the only outcropping continental sequences constrained to have been in the equatorial zone of Triassic Pangea. The development of a precise spatiotemporal framework is prompted by the exciting discovery of unexpectedly rich, seemingly endemic tetrapod assemblages from these basins that suggest new interpretations of the pattern of Late Triassic faunal evolution. These faunules contain surprisingly large numbers of synapsids (dicynodonts, traversodonts, and advanced cynodonts) that differentiate these paleoequatorial assemblages from coeval ones of the more northern Triassic rifts, as well as those from the classic Chinle Group of the American Southwest. In addition, elements of these faunules provide conflicting biostratigraphic information requiring independent mechanisms for assessing their age and correlation. We propose to use paleomagnetic and cyclostratigraphic means to place these new and previously discovered assemblages into a tightly constrained paleogeographic and temporal framework correlated to the well-defined Newark Basin time scale developed through previous NSF-funded work. We anticipate that this project will have major implications for the rates and taxonomic and geographic patterns of Triassic terrestrial faunal change, as well as the character and consequences of the Triassic-Jurassic mass extinction.

该项目的目标是为北美东部最南端暴露的三叠纪裂谷盆地（特别是深河和丹河盆地，以及较小范围的里士满和泰勒斯维尔盆地）开发高分辨率的年代学、地层学和古地理框架。这些盆地构成了三叠纪盘古大陆赤道地区唯一露头的大陆序列。这些盆地中出乎意料地丰富、看似特有的四足动物组合的令人兴奋的发现促进了精确时空框架的发展，这对晚三叠世动物群进化模式提出了新的解释。这些动物群含有数量惊人的合弓动物（二齿兽类、横齿兽类和高级犬齿兽类），这些动物群将这些古赤道组合与更北部三叠纪裂谷的同期组合以及来自美国西南部经典钦利群的组合区分开来。此外，这些动物群的元素提供了相互矛盾的生物地层信息，需要独立的机制来评估它们的年龄和相关性。我们建议使用古地磁和旋回地层学手段将这些新的和先前发现的组合放入严格约束的古地理和时间框架中，该框架与通过之前的 NSF 资助的工作开发的明确的纽瓦克盆地时间尺度相关。我们预计该项目将对三叠纪陆地动物群变化的速度、分类和地理模式以及三叠纪-侏罗纪大规模灭绝的特征和后果产生重大影响。