干旱区生态环境知识资源中心(Arid): Climatic and sea-level control of Jurassic (Pliensbachian) clay mineral sedimentation in the Cardigan Bay Basin, Llanbedr (Mochras Farm) borehole, Wales

Arid

DOI	10.1111/sed.12610
	Climatic and sea-level control of Jurassic (Pliensbachian) clay mineral sedimentation in the Cardigan Bay Basin, Llanbedr (Mochras Farm) borehole, Wales
	Deconinck, Jean-Francois 1; Hesselbo, Stephen P.2,3; Pellenard, Pierre 1
通讯作者	Deconinck, Jean-Francois
来源期刊	SEDIMENTOLOGY
ISSN	0037-0746
EISSN	1365-3091
出版年	2019
卷号	66 期号:7 页码:2769-2783
英文摘要	Early Jurassic climate is characterized by alternating cold and warm periods highlighted by studies based notably on oxygen isotopes measured on belemnite guards and other marine invertebrate shells. These climatic changes include changes in the hydrological cycle, and consequently weathering and runoff conditions. In order to clarify the erosion and weathering conditions during the Pliensbachian, this study determined the mineralogical composition of the clay fraction of 132 samples taken from the entire stage drilled in the Llanbedr (Mochras Farm) borehole (Cardigan Bay Basin). The clay mineral assemblages are composed of various proportions of chlorite, illite, illite/smectite mixed-layers (R1 I-S), smectite and kaolinite, with possibly occasional traces of berthierine. The occurrence of abundant smectite indicates that the maximum burial temperature never exceeded 70 degrees C. Consequently, clay minerals are considered mainly detrital, and their fluctuations likely reflect environmental changes. The variations in the proportions of smectite and kaolinite are opposite to each other. Kaolinite is particularly abundant at the base of the jamesoni Zone, in part coinciding with the delta C-13 negative excursion corresponding to the Sinemurian/Pliensbachian Boundary Event, and through the davoei Zone, whilst smectite is abundant in the upper part of jamesoni and base of ibex zones and through the subnodosus/gibbosus subzones of the margaritatus Zone. The kaolinite-rich intervals reflect an intensification of hydrolysis and an acceleration of the hydrological cycle, while the smectite-rich intervals indicate a more arid climate. The spinatum Zone is characterized by a distinct clay assemblage with abundant primary minerals, R1 I-S, kaolinite reworked from previously deposited sediments or from Palaeozoic rocks, and probably berthierine originating from contemporaneous ironstone-generating environments of shallower waters. This mineralogical change by the end of the Pliensbachian likely reflects a transition from a dominant chemical weathering to a deeper physical erosion of the continent, probably related to a significant sea-level fall consistent with a glacio-eustatic origin.
英文关键词	Clay minerals clay sedimentation Early Jurassic palaeoclimate Pliensbachian
类型	Article
语种	英语
国家	France ; England
开放获取类型	hybrid, Green Accepted
收录类别	SCI-E
WOS记录号	WOS:000497136500009
WOS关键词	OCEANIC ANOXIC EVENT ; CARBON-CYCLE ; ENVIRONMENTAL CONTROLS ; CRETACEOUS SEDIMENTS ; AUTHIGENIC ZEOLITES ; MECSEK MOUNTAINS ; CLEVELAND BASIN ; ISOTOPE RECORDS ; ASTURIAN BASIN ; PARIS BASIN
WOS类目	Geology
WOS研究方向	Geology
EI主题词	2019-12-01
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/311131
作者单位	1.UBFC, CNRS, UMR 6282, Biogeosci, 6 Blvd Gabriel, F-21000 Dijon, France; 2.Univ Exeter, Camborne Sch Mines, Penryn Campus, Penryn TR10 9EZ, Cornwall, England; 3.Univ Exeter, Environm & Sustainabil Inst, Penryn Campus, Penryn TR10 9EZ, Cornwall, England
推荐引用方式 GB/T 7714	Deconinck, Jean-Francois,Hesselbo, Stephen P.,Pellenard, Pierre. Climatic and sea-level control of Jurassic (Pliensbachian) clay mineral sedimentation in the Cardigan Bay Basin, Llanbedr (Mochras Farm) borehole, Wales[J],2019,66(7):2769-2783.
APA	Deconinck, Jean-Francois,Hesselbo, Stephen P.,&Pellenard, Pierre.(2019).Climatic and sea-level control of Jurassic (Pliensbachian) clay mineral sedimentation in the Cardigan Bay Basin, Llanbedr (Mochras Farm) borehole, Wales.SEDIMENTOLOGY,66(7),2769-2783.
MLA	Deconinck, Jean-Francois,et al."Climatic and sea-level control of Jurassic (Pliensbachian) clay mineral sedimentation in the Cardigan Bay Basin, Llanbedr (Mochras Farm) borehole, Wales".SEDIMENTOLOGY 66.7(2019):2769-2783.