Determining the geographical extent and radiometric age of the Paleocene-Eocene boundary ejecta strewn field

GSTDTAP

项目编号	1737100
	Determining the geographical extent and radiometric age of the Paleocene-Eocene boundary ejecta strewn field
	Morgan Schaller
主持机构	Rensselaer Polytechnic Institute
项目开始年	2017
	2017-09-01
项目结束日期	2019-08-31
资助机构	US-NSF
项目类别	Standard Grant
项目经费	349976(USD)
国家	美国
语种	英语
英文摘要	Extraterrestrial impacts have played a substantial role in shaping the evolution of life on this planet. In 2016, evidence was discovered of an impact event that coincided with a major climatic event 56 million years ago at the Paleocene-Eocene (P-E) boundary. Evidence includes characteristic glass spherules and shocked mineral grains (known as ejecta) that were thrown from the impact site. The first solid evidence of an extraterrestrial impact at the P-E boundary raises many questions about the potential location of the source crater, the extent of the strewn field and exact age of the material. This project will determine the global geographic extent and the absolute age of the ejecta through an extensive search of sediments at known localities where the P-E boundary is complete and by radiometrically dating the material. The P-E climate event is marked by a rapid increase in atmospheric carbon accompanied by 5-8 degrees C global warming. It is important to understand the conditions surrounding this event because it is the best geologic analog to our current anthropogenic carbon release and climate change, and regardless of the triggering mechanism, gives us a roadmap for what to expect in the future. This time period also marks the origination of the primate lineage that ultimately resulted in the evolution of humans. Understanding the circumstances of the impact event at the P-E boundary will significantly advance our scientific understanding of the evolution of life and climate over the past 56 million years. Broader impacts of the project include the support of a postdoctoral scholar, several undergraduate students and two principal investigators, one of whom is early career. High school science teachers will also engage in the study during the summer. This research builds on recent findings of extraterrestrial impact ejecta at the P-E boundary in the Atlantic coastal plain and in sediments from the Blake Nose section offshore Florida. Ejecta material was found within the onset of the negative Carbon Isotope Excursion (CIE) that marks the P-E boundary globally. This study's research approach is similar to the search for the Cretaceous-Paleogene (K-Pg) boundary impact crater that eventually led to the discovery of the Chicxulub impact site. The project aims to provide the first radiometrically dated and potentially global fiducial marker for the P-E boundary. Anticipated results include: 1) strewn field map and location of P-E impact region; 2) radiometric age of P-E boundary using 40Ar/39Ar methods; 3) establishment of P-E ejecta as a precise temporal horizon and correlation tool; and 4) framework for future research (a) to address any causal linkages between the P-E impact and the P-E climate perturbation and (b) to assess the precise timing of the P-E biotic and climatic changes and the globally observed CIE. The climatic and biotic changes that occur at the P-E boundary are substantial; for instance, the primate lineage that eventually led to humans arose at this boundary, and deep ocean changes resulted in mass extinction in benthic marine microfauna. Hence, if an extraterrestrial impact played a role in this chapter of Earth History, the record and circumstances of such an event are crucial observations.
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/71856
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Morgan Schaller.Determining the geographical extent and radiometric age of the Paleocene-Eocene boundary ejecta strewn field.2017.