气候变化领域集成服务门户(CCPortal): Changes in foraminiferal assemblages and environmental conditions during the T-OAE (Early Jurassic) in the northern Lusitanian Basin; Portugal

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DOI	10.1016/j.palaeo.2019.01.022
	Changes in foraminiferal assemblages and environmental conditions during the T-OAE (Early Jurassic) in the northern Lusitanian Basin; Portugal
	Reolid M.; Duarte L.V.; Rita P.
发表日期	2019
ISSN	0031-0182
起始页码	30
结束页码	43
卷号	520
英文摘要	The foraminiferal assemblages and other microfossils from the Rabaçal area (Maria Pares section) in the Lusitanian Basin (Portugal) provide new insights regarding the Toarcian Oceanic Anoxic Event (T-OAE). Complementary analysis of the δ 13 C, total organic carbon (TOC) and geochemical redox and palaeoproductivity proxies reflect environmental changes that affected the microfossil assemblages. Detailed analyses of foraminiferal assemblages (their diversity, abundance, morphogroups and lifestyle) and geochemistry led us to discern phases of the biotic crisis and subsequent stages of recovery. Environmental instability, which began in the lattermost part of the Polymorphum Zone, is marked by a lesser abundance of foraminifera and ostracods, increased opportunist foraminifera, fluctuations in TOC values and the enrichment factor of phosphorous (P EF ), as well as the onset of a negative carbon isotopic excursion (CIE). The peak phase of the biotic crisis corresponds with the lowest values for foraminiferal diversity and abundance (including a barren sample for benthic microfossils). The abundance and diversity of echinoderms, brachiopods, dinoflagellate cysts and calcareous nannofossils dropped sharply during the peak phase. This biotic crisis also entails extinction of the Order Metacopina and a local disappearance of echinoderms and brachiopods. Anoxic conditions at sea bottom did not develop, given the almost continuous record of foraminifera and trace fossils, yet oxygen-depleted conditions occurred. The lower part of the Levisoni Zone contains thin nodular limestones corresponding to a tempestitic–turbiditic facies. In this context, the re-oxygenation of bottom waters was favoured, as indicated by the presence of Thalassinoides and the low values of TOC and redox-sensitive elements (Mo, Ni and U). The survival phase in the wake of the biotic crisis is characterized by greater diversity and abundance of foraminifera and echinoderms (holothuroids and ophiuroids). The lowest δ 13 C values are recorded during this phase, with a dominance of opportunist (Eoguttulina) and facultative opportunist (Paralingulina tenera) foraminifera. Finally, recovery after the biotic crisis is evidenced by high values for specialists and potentially deep infaunal foraminifera, indicating oxic conditions in the sediment. © 2019 Elsevier B.V.
英文关键词	Foraminiferal morphogroups; Iberian Palaeomargin; Maria Pares section; Opportunists; Oxygen-depleted conditions
语种	英语
scopus关键词	abundance; carbon isotope; dinoflagellate cyst; echinoderm; environmental conditions; foraminifera; geochemistry; Jurassic; microfossil; morphotype; organic carbon; ostracod; oxygen; paleoproductivity; species diversity; total organic carbon; Atlantic Ocean; Iberian Peninsula; Lisboa [Portugal]; Lusitanian Basin; Portugal; Brachiopoda; Dinophyceae; Echinodermata; Foraminifera; Holothuroidea; Metacopina; Ophiuroidea; Ostracoda; Thalassinoides
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/151035
作者单位	Dept. Geología and CEACT, Universidad de Jaén, Campus Las Lagunillas snJaén 23071, Spain; MARE and Dept. Ciências da Terra, Universidade de Coimbra, Polo II, Rua Silvio Lima, Coimbra, 3030-790, Portugal; GeoZentrum Nordbayern, Universität Erlangen-Nürnberg (FAU), Loewenichstraße 28, Erlangen, 91054, Germany
推荐引用方式 GB/T 7714	Reolid M.,Duarte L.V.,Rita P.. Changes in foraminiferal assemblages and environmental conditions during the T-OAE (Early Jurassic) in the northern Lusitanian Basin; Portugal[J],2019,520.
APA	Reolid M.,Duarte L.V.,&Rita P..(2019).Changes in foraminiferal assemblages and environmental conditions during the T-OAE (Early Jurassic) in the northern Lusitanian Basin; Portugal.Palaeogeography, Palaeoclimatology, Palaeoecology,520.
MLA	Reolid M.,et al."Changes in foraminiferal assemblages and environmental conditions during the T-OAE (Early Jurassic) in the northern Lusitanian Basin; Portugal".Palaeogeography, Palaeoclimatology, Palaeoecology 520(2019).