气候变化领域集成服务门户(CCPortal): Facies interpretation and geochronology of diverse Eocene floras and faunas, northwest Chubut Province, Patagonia, Argentina

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DOI	10.1130/B35611.1
	Facies interpretation and geochronology of diverse Eocene floras and faunas, northwest Chubut Province, Patagonia, Argentina
	Gosses J.; Carroll A.R.; Bruck B.T.; Singer B.S.; Jicha B.R.; Aragón E.; Walters A.P.; Wilf P.
发表日期	2021
ISSN	167606
起始页码	740
结束页码	752
卷号	133 期号:2021-03-04
英文摘要	The Eocene Huitrera Formation of northwestern Patagonia, Argentina, is renowned for its diverse, informative, and outstandingly preserved fossil biotas. In northwest Chubut Province, at the Laguna del Hunco locality, this unit includes one of the most diverse fossil floras known from the Eocene, as well as significant fossil insects and vertebrates. It also includes rich fossil vertebrate faunas at the Laguna Fría and La Barda localities. Previous studies of these important occurrences have provided relatively little sedimentological detail, and radioisotopic age constraints are relatively sparse and in some cases obsolete. Here, we describe five fossiliferous lithofacies deposited in four terrestrial depositional environments: lacustrine basin floor, subaerial pyroclastic plain, vegetated, waterlogged pyroclastic lake margin, and extracaldera incised valley. We also report several new 40Ar/39Ar age determinations. Among these, the uppermost unit of the caldera-forming Ignimbrita Barda Colorada yielded a 40Ar/39 Ar age of 52.54 ± 0.17 Ma, ∼6 m.y. younger than previous estimates, which demonstrates that deposition of overlying fossiliferous lacustrine strata (previously constrained to older than 52.22 ± 0.22 Ma) must have begun almost immediately on the subsiding ignimbrite surface. A minimum age for Laguna del Hunco fossils is established by an overlying ignimbrite with an age of 49.19 ± 0.24 Ma, confirming that deposition took place during the early Eocene climatic optimum. The Laguna Fría mammalian fauna is younger, constrained between a valley-filling ignimbrite and a capping basalt with 40Ar/39Ar ages of 49.26 ± 0.30 Ma and 43.50 ± 1.14 Ma, respectively. The latter age is ∼4 m.y. younger than previously reported. These new ages more precisely define the age range of the Laguna Fría and La Barda faunas, allowing greatly improved understanding of their positions with respect to South American mammal evolution, climate change, and geographic isolation. © 2020. Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184691
作者单位	Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton Street, Madison, Wisconsin 53706, United States; Centro de Investigaciones Geológicas-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de la Plata, La Plata, B1900FWA, Argentina; Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, United States; Office of the Chief Information Officer, NASA Johnson Space Center, 2101 NASA Parkway, Houston, Texas 77058, United States
推荐引用方式 GB/T 7714	Gosses J.,Carroll A.R.,Bruck B.T.,et al. Facies interpretation and geochronology of diverse Eocene floras and faunas, northwest Chubut Province, Patagonia, Argentina[J],2021,133(2021-03-04).
APA	Gosses J..,Carroll A.R..,Bruck B.T..,Singer B.S..,Jicha B.R..,...&Wilf P..(2021).Facies interpretation and geochronology of diverse Eocene floras and faunas, northwest Chubut Province, Patagonia, Argentina.Bulletin of the Geological Society of America,133(2021-03-04).
MLA	Gosses J.,et al."Facies interpretation and geochronology of diverse Eocene floras and faunas, northwest Chubut Province, Patagonia, Argentina".Bulletin of the Geological Society of America 133.2021-03-04(2021).