DOI: 10.1016/j.gloplacha.2017.01.005
论文题名: Climatic and palaeoceanographic changes during the Pliensbachian (Early Jurassic) inferred from clay mineralogy and stable isotope (C-O) geochemistry (NW Europe)
作者: Bougeault C. ; Pellenard P. ; Deconinck J.-F. ; Hesselbo S.P. ; Dommergues J.-L. ; Bruneau L. ; Cocquerez T. ; Laffont R. ; Huret E. ; Thibault N.
刊名: Global and Planetary Change
ISSN: 0921-8181
出版年: 2017
卷: 149 起始页码: 139
结束页码: 152
语种: 英语
英文关键词: Clay minerals
; Early Jurassic
; Glacio-eustasy
; Pliensbachian
; Runoff
; Stable isotope
Scopus关键词: Biogeochemistry
; Biological materials
; Floods
; Geochemistry
; Isotopes
; Kaolinite
; Minerals
; Organic compounds
; Organic minerals
; Runoff
; Sea level
; Underwater mineralogy
; Early Jurassic
; Eustasy
; Geochemical evidence
; Negative carbon isotope excursions
; Oceanic circulations
; Organic matter burial
; Pliensbachian
; Stable isotopes
; Clay minerals
; Capra ibex
英文摘要: The Early Jurassic was broadly a greenhouse climate period that was punctuated by short warm and cold climatic events, positive and negative excursions of carbon isotopes, and episodes of enhanced organic matter burial. Clay minerals from Pliensbachian sediments recovered from two boreholes in the Paris Basin, are used here as proxies of detrital supplies, runoff conditions, and palaeoceanographic changes. The combined use of these minerals with stable isotope data (C-O) from bulk carbonates and organic matter allows palaeoclimatic reconstructions to be refined for the Pliensbachian. Kaolinite/illite ratio is discussed as a reliable proxy of the hydrological cycle and runoff from landmasses. Three periods of enhanced runoff are recognised within the Pliensbachian. The first one at the Sinemurian-Pliensbachian transition shows a significant increase of kaolinite concomitant with the negative carbon isotope excursion at the so-called Sinemurian Pliensbachian Boundary Event (SPBE). The Early/Late Pliensbachian transition was also characterised by more humid conditions. This warm interval is associated with a major change in oceanic circulation during the Davoei Zone, likely triggered by sea-level rise; the newly created palaeogeography, notably the flooding of the London-Brabant Massif, allowed boreal detrital supplies, including kaolinite and chlorite, to be exported to the Paris Basin. The last event of enhanced runoff occurred during the late Pliensbachian (Subnodosus Subzone of the Margaritatus Zone), which occurred also during a warm period, favouring organic matter production and preservation. Our study highlights the major role of the London Brabant Massif in influencing oceanic circulation of the NW European area, as a topographic barrier (emerged lands) during periods of lowstand sea-level and its flooding during period of high sea-level. This massif was the unique source of smectite in the Paris Basin. Two episodes of smectite-rich sedimentation (‘smectite events’), coincide with regressive intervals, indicating emersion of the London Brabant Massif and thus suggesting that an amplitude of sea-level change high enough to be linked to glacio-eustasy. This mechanism is consistent with sedimentological and geochemical evidences of continental ice growth notably during the Latest Pliensbachian (Spinatum Zone), and possibly during the Early Pliensbachian (late Jamesoni/early Ibex Zones). © 2017 Elsevier B.V. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85010756949&doi=10.1016%2fj.gloplacha.2017.01.005&partnerID=40&md5=4dec5403191c32fbc1be997934fcbdac
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/11766
Appears in Collections: 全球变化的国际研究计划 气候变化与战略
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作者单位: UMR CNRS 6282 Biogéosciences, Univ. Bourgogne Franche-Comté, 6 Boulevard Gabriel, Dijon, France
Recommended Citation:
Bougeault C.,Pellenard P.,Deconinck J.-F.,et al. Climatic and palaeoceanographic changes during the Pliensbachian (Early Jurassic) inferred from clay mineralogy and stable isotope (C-O) geochemistry (NW Europe)[J]. Global and Planetary Change,2017-01-01,149.