DOI: 10.1016/j.gloplacha.2015.05.002
论文题名: Organic matter production and preservation in the Lusitanian Basin (Portugal) and Pliensbachian climatic hot snaps
作者: Silva R.L. ; Duarte L.V.
刊名: Global and Planetary Change
ISSN: 0921-8181
出版年: 2015
卷: 131 起始页码: 24
结束页码: 34
语种: 英语
英文关键词: Black shales
; Elemental geochemistry
; Paleoceanography
; Pliensbachian, Lusitanian Basin
Scopus关键词: Biogeochemistry
; Biological materials
; Gas hydrates
; Geochemistry
; Glacial geology
; Methane
; Oil shale
; Organic compounds
; Unloading
; Uranium
; Black shales
; Elemental geochemistry
; Hemipelagic deposits
; Lusitanian basins
; Methane gas hydrates
; Paleoceanography
; Preservation of organic matters
; Volcanic activities
; Shale
; black shale
; carbonate
; climate effect
; facies
; organic matter
; Pliensbachian
; sequence stratigraphy
; Atlantic Ocean
; Lisboa [Portugal]
; Lusitanian Basin
; Portugal
; Portugal
; Ammonoidea
; Capra ibex
英文摘要: The Pliensbachian (Early Jurassic) hemipelagic carbonate series of the Lusitanian Basin (Portugal) are of major importance as this basin is located at a key position between the Tethyan and Boreal (North European) realms. One of the most conspicuous features of this basin is the organic-rich nature of most of the Margaritatus Chronozone hemipelagic deposits, with the occurrence of several well-defined regional black shales. The analysis of selected redox sensitive elements (V, Cr, Co, Ni, Mo, and U) from the worldwide reference section of Peniche indicates that in this basin most of the organic-rich facies of the Ibex-Margaritatus chronozones were deposited under an oxic-dysoxic regime, while the rare centimetre thick well-defined black shales were deposited and preserved under suboxic-anoxic, intermittently euxinic conditions. Based on the integration of sedimentological, biostratigraphical, geochemical, and organic petrographic evidence we suggest that these basinwide black shales, corresponding to widespread mucilage and microbial outbreaks, were driven by extreme climate warming coupled with high oceanic productivity and intermittently stratified epeiric seas. Regionally, these "hot snaps" may have promoted the observed rapid but short-lived expansion of Tethyan ammonites into Boreal domains or led to decrease benthic diversity. Ensuing cooling during the Margaritatus Chronozone was accompanied by southwards influx of northwards ammonite fauna or radiation of cyst forming dinoflagellates.Worldwide preservation of organic matter during the Late Pliensbachian seems to have resulted in decreased atmospheric CO2 levels through geological storage of carbon, triggering and/or amplifying the Spinatum Chronozone icehouse event. Ultimately, this cooling event may have led to the occurrence of permafrost and/or methane gas hydrates in locations easily disturbed by the subsequent Early Toarcian warming, or/and volcanic activity driven by crustal unloading due to deglaciation. © 2015 Elsevier B.V. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84929580174&doi=10.1016%2fj.gloplacha.2015.05.002&partnerID=40&md5=ff850ffe4ad62e7a6670a6bf54ae386a
Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/11509
Appears in Collections: 全球变化的国际研究计划 气候变化与战略
There are no files associated with this item.
作者单位: Basin and Reservoir Lab, Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada
Recommended Citation:
Silva R.L.,Duarte L.V.. Organic matter production and preservation in the Lusitanian Basin (Portugal) and Pliensbachian climatic hot snaps[J]. Global and Planetary Change,2015-01-01,131.