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DOI	10.1016/j.palaeo.2018.06.037
	Revised perspectives on Devonian biozonation and environmental volatility in the wake of recent time-scale revisions
	Brett C.E.; Zambito J.J.; IV; McLaughlin P.I.; Emsbo P.
发表日期	2020
ISSN	0031-0182
卷号	549
英文摘要	Revised time-scales for the Devonian Period have highlighted major discrepancies in the frequency of evolutionary, eustatic, carbon cycle, and biotic events. The number of conodont biozones per million years shows strong variation among stages. Using two alternative time scales, the lowest values are in the Emsian and highest in the Givetian, Frasnian, and Famennian stages. A similar result is obtained by dividing the Devonian time scale into 12 equal 5-million year bins and determining the number of conodont zonal subdivisions in each bin. The record of ammonoid biozones also shows interesting parallels. The acuity of biostratigraphic zonation and zonal subdivisions appears to be correlative with the frequency of environmental perturbations, including eustatic, positive carbon isotopic excursions, and hypoxic/anoxic related bioevents, and these are similarly unevenly distributed. All calculations of environmental volatility metrics show the late Eifelian through early Frasnian to be the most volatile interval of the Devonian, followed by the mid-late Famennian, while the Lochkovian through Emsian and mid-Frasnian through early Famennian are the least volatile. Furthermore, the majority of major bioevents occur in the Eifelian through early Frasnian, and late Famennian. The strong evidence for higher biotic and environmental volatility in the late Eifelian through early Frasnian and late Famennian rock record corresponds to the coolest paleoclimate conditions in the Devonian according to recent conodont apatite δ18O compilations, and the transition from an overall cooling to warming paleotemperature trend during the mid-Givetian. Regardless of mechanism, strong variations in volatility occurred during the Devonian Period. Intervals with greater biostratigraphic resolution also show much stronger environmental volatility including a series of relatively quasi-stable conditions punctuated by major turnovers with abrupt sea-level rise, widespread hypoxia, and changes in the carbon cycle. It was during these intervals that much net evolutionary and ecological change appears to have taken place. © 2018 Elsevier B.V.
英文关键词	Astrochronology; Bioevents; Biostratigraphy; Carbon isotopes; Chronostratigraphy; Eustatic
语种	英语
scopus关键词	apatite; biostratigraphy; biozonation; climate conditions; conodont; cooling; Devonian; paleoclimate; paleotemperature; Ammonoidea
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150517
作者单位	University of Cincinnati, Geology Department, Cincinnati, OH 45221-0013, United States; Wisconsin Geological and Natural History Survey, University of Wisconsin, 3817 Mineral Point Road, Madison, WI 53705, United States; Indiana Geological and Water Survey, University of Indiana, 611 N. Walnut Grove, Bloomington, IN 47405, United States; United States Geological Survey, MS 973, Box 25046, Denver, CO 80225, United States
推荐引用方式 GB/T 7714	Brett C.E.,Zambito J.J.,IV,et al. Revised perspectives on Devonian biozonation and environmental volatility in the wake of recent time-scale revisions[J],2020,549.
APA	Brett C.E.,Zambito J.J.,IV,McLaughlin P.I.,&Emsbo P..(2020).Revised perspectives on Devonian biozonation and environmental volatility in the wake of recent time-scale revisions.Palaeogeography, Palaeoclimatology, Palaeoecology,549.
MLA	Brett C.E.,et al."Revised perspectives on Devonian biozonation and environmental volatility in the wake of recent time-scale revisions".Palaeogeography, Palaeoclimatology, Palaeoecology 549(2020).