气候变化领域集成服务门户(CCPortal): Early Paleogene biosiliceous sedimentation in the Atlantic Ocean: Testing the inorganic origin hypothesis for Paleocene and Eocene chert and porcellanite

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DOI	10.1016/j.palaeo.2020.109896
	Early Paleogene biosiliceous sedimentation in the Atlantic Ocean: Testing the inorganic origin hypothesis for Paleocene and Eocene chert and porcellanite
	Witkowski J.; Penman D.E.; Bryłka K.; Wade B.S.; Matting S.; Harwood D.M.; Bohaty S.M.
发表日期	2020
ISSN	0031-0182
卷号	556
英文摘要	The widespread occurrence of lower Eocene chert and porcellanite has been viewed as a major paleoceanographic issue since the advent of ocean drilling, and both biotic and abiotic forcings have been proposed to explain it. We present a reconstruction of indurated siliceous sediment (ISS) and preserved biosiliceous sediment (PBS) occurrences in the Atlantic Ocean through the Paleocene and Eocene (~66 through 34 Ma). ISS and PBS distributions reveal dissimilar temporal trends, with the peak of ISS occurrences coinciding with the Early Eocene Climatic Optimum, in line with previous studies. PBS occurrences show a generally increasing trend culminating between 44 and 43 Ma. The common co-occurrence of ISS and PBS, and their coherent geographic distribution lends strong support to the biogenic origin of the precursor to the widespread Paleogene ISS, and argues against an inorganic mode of early Cenozoic chert and porcellanite precipitation. Weight per cent biogenic opal records and trends in linear sedimentation rates indicate two plausible modes of silicification: 1) silicification due to prolonged exposure of biogenic opal-rich sediments to corrosive bottom waters; and 2) silicification due to elevated pressures and temperatures caused by rapid burial of biogenic opal-rich deposits. The confinement of ISS and PBS to proximal sites along continental margins points to the reliance of siliceous sedimentation through the Paleocene and Eocene on terrestrial supply of dissolved silicon. Consistent with this, quantitative siliceous microfossil assemblage records from the Blake Nose in the NW Atlantic indicate that the nutrient-rich marginal rather than oligotrophic pelagic settings hosted the majority of siliceous plankton production through the early Paleogene. The inorganic SiO2 precipitation model is unlikely to have been the dominant mechanism responsible for ubiquitous occurrences of early Paleogene ISS. We favor the biogenic ISS precursor scenario and reconcile it with the low-productivity early Cenozoic oceans by showing that large volumes of biogenic silica were supplied to the western North Atlantic Ocean from the North American margin through the Paleocene and Eocene. Dissolution of this surplus silica was facilitated by an early southwestward flow of young, SiO2-depleted waters from the North Atlantic. All these factors contributed to ISS and PBS focusing in the western North Atlantic through the early Paleogene. © 2020 Elsevier B.V.
英文关键词	Biogenic silica; Blake Nose; Diagenesis; Diatoms; Ocean drilling; Paleoceanography
语种	英语
scopus关键词	Cenozoic; Eocene; microfossil; Paleocene-Eocene boundary; Paleogene; plankton; porcellanite; reconstruction; sedimentation; silica; silicification; Atlantic Ocean; Atlantic Ocean (North); Blake Nose; Blake Plateau; Bacillariophyta
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/150385
作者单位	Institute of Marine and Envrionmental Sciences, University of Szczecin, ul. Mickiewicza 18, Szczecin, 70-383, Poland; Geology and Geophysics, Yale University, 210 Whitney Ave, New Haven, CT 06511, United States; Department of Geology, Faculty of Science, Lund University, Sölvegatan 12, Lund, Sweden; Department of Earth Sciences, University College of London, Gower Street, London, WC1E 6BT, United Kingdom; Geological Survey of Mecklenburg-Western Pomerania, LUNG M-V, Goldberger Str. 12, Güstrow, 18273, Germany; Institute of Geography and Geology, University of Greifswald, F.-L.-Jahn-Str. 15a, Greifswald, 17487, Germany; Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588-0340, United States; Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, United Kingdom
推荐引用方式 GB/T 7714	Witkowski J.,Penman D.E.,Bryłka K.,et al. Early Paleogene biosiliceous sedimentation in the Atlantic Ocean: Testing the inorganic origin hypothesis for Paleocene and Eocene chert and porcellanite[J],2020,556.
APA	Witkowski J..,Penman D.E..,Bryłka K..,Wade B.S..,Matting S..,...&Bohaty S.M..(2020).Early Paleogene biosiliceous sedimentation in the Atlantic Ocean: Testing the inorganic origin hypothesis for Paleocene and Eocene chert and porcellanite.Palaeogeography, Palaeoclimatology, Palaeoecology,556.
MLA	Witkowski J.,et al."Early Paleogene biosiliceous sedimentation in the Atlantic Ocean: Testing the inorganic origin hypothesis for Paleocene and Eocene chert and porcellanite".Palaeogeography, Palaeoclimatology, Palaeoecology 556(2020).