气候变化领域集成服务门户(CCPortal): A chronostratigraphic framework for the upper Stormberg Group: Implications for the Triassic-Jurassic boundary in southern Africa

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DOI	10.1016/j.earscirev.2020.103120
	A chronostratigraphic framework for the upper Stormberg Group: Implications for the Triassic-Jurassic boundary in southern Africa
	Bordy E.M.; Abrahams M.; Sharman G.R.; Viglietti P.A.; Benson R.B.J.; McPhee B.W.; Barrett P.M.; Sciscio L.; Condon D.; Mundil R.; Rademan Z.; Jinnah Z.; Clark J.M.; Suarez C.A.; Chapelle K.E.J.; Choiniere J.N.
发表日期	2020
ISSN	0012-8726
卷号	203
英文摘要	The upper Stormberg Group (Elliot and Clarens formations) of the main Karoo Basin is well-known for its fossil vertebrate fauna, comprising early branching members of lineages including mammals, dinosaurs, and turtles. Despite 150 years of scientific study, the upper Stormberg Group lacks radioisotopic age constraints and remains coarsely dated via imprecise faunal correlations. Here we synthesise previous litho- and magnetostratigraphic studies, and present a comprehensive biostratigraphic review of the upper Stormberg fauna. We also present the results of the first geochronological assessment of the unit across the basin, using U-Pb dates derived from detrital zircons obtained from tuffaceous sandstones and siltstones, the youngest of which are considered maximum depositional ages. Our results confirm that the Elliot Formation contains the Triassic–Jurassic boundary, making it one of the few fossiliferous continental units that records the effects of the end-Triassic Mass Extinction event. Our work suggests a mid-Norian–Rhaetian age for the lower Elliot Formation and a Hettangian–Sinemurian age for the upper Elliot Formation, although the precise stratigraphic position of the Triassic/Jurassic (Rhaetian/Hettangian) boundary remains somewhat uncertain. A mainly Pliensbachian age is obtained for the Clarens Formation. The new dates allow direct comparison with better-calibrated Triassic-Jurassic faunas of the Western Hemisphere (e.g., Chinle and Los Colorados formations). We show that sauropodomorph, but not ornithischian or theropod, dinosaurs were well-established in the main Karoo Basin ~220 million years ago, and that typical Norian faunas (e.g., aetosaurs, phytosaurs) are either rare or absent in the lower Elliot Formation, which is paucispecific compared to the upper Elliot. While this is unlikely the result of geographic sampling biases, it could be due to historical sampling intensity differences. © 2020 Elsevier B.V.
英文关键词	Early dinosaurs; Elliot Formation; Magnetostratigraphy; Main Karoo Basin; U–Pb detrital zircon geochronology; Vertebrate biostratigraphy
语种	英语
scopus关键词	biostratigraphy; calibration; chronostratigraphy; detrital deposit; fossil assemblage; Jurassic; lithostratigraphy; magnetostratigraphy; stratigraphic boundary; Triassic; uranium-lead dating; zircon; Karoo; South Africa; Dinosauria; Mammalia; Ornithischia; Sauropodomorpha; Testudines; Theropoda; Vertebrata
来源期刊	EARTH-SCIENCE REVIEWS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/209655
作者单位	Department of Geological Sciences, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa; Department of Geosciences, University of Arkansas, 340 N. Campus Drive, Fayetteville, AR 72701, United States; Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg, 2050, South Africa; Integrative Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605, United States; School of Geosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg, 2050, South Africa; Department of Earth Sciences, University of Oxford, Oxford, OX1 3AN, United Kingdom; Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, United Kingdom; Department of Geology, University of Johannesburg, Kingsway and Auckland Park, Johannesburg, 2006, South Africa; British Geological Survey (BGS), Keyworth, Nottingham, NG12 5GG, United Kingdom; Berkeley Geochronology Center (BGC), 2455 Ridge Road, Berkeley...
推荐引用方式 GB/T 7714	Bordy E.M.,Abrahams M.,Sharman G.R.,et al. A chronostratigraphic framework for the upper Stormberg Group: Implications for the Triassic-Jurassic boundary in southern Africa[J],2020,203.
APA	Bordy E.M..,Abrahams M..,Sharman G.R..,Viglietti P.A..,Benson R.B.J..,...&Choiniere J.N..(2020).A chronostratigraphic framework for the upper Stormberg Group: Implications for the Triassic-Jurassic boundary in southern Africa.EARTH-SCIENCE REVIEWS,203.
MLA	Bordy E.M.,et al."A chronostratigraphic framework for the upper Stormberg Group: Implications for the Triassic-Jurassic boundary in southern Africa".EARTH-SCIENCE REVIEWS 203(2020).