气候变化领域集成服务门户(CCPortal): Sedimentary organic matter and δ13CKerogen variation on the southern Iberian palaeomargin (Betic Cordillera; SE Spain) during the latest Pliensbachian

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DOI	10.1016/j.palaeo.2019.109342
	Sedimentary organic matter and δ13CKerogen variation on the southern Iberian palaeomargin (Betic Cordillera; SE Spain) during the latest Pliensbachian–Early Toarcian
	Rodrigues B.; Silva R.L.; Reolid M.; Mendonça Filho J.G.; Duarte L.V.
发表日期	2019
ISSN	0031-0182
卷号	534
英文摘要	The Early Toarcian Oceanic Anoxic Event (T-OAE) is characterised by major palaeoenvironmental and palaeoceanographical changes (ocean anoxia, global warming, ocean acidification, among other), and a severe perturbation of the global carbon cycle. Although widespread oceanic anoxia was a significant control on the occurrence of organic-rich facies during the T-OAE in several locations of the northern Tethyan margin, the effects of anoxia, oceanic productivity, and dilution are poorly understood in other worldwide locations, such as the southern Tethyan and Iberian margins. In this study, we report new geochemical [total organic carbon (TOC), total sulphur (TS), total carbonate content (CaCO3), δ13C from kerogen isolates (δ13CKerogen)], palynofacies and thermal maturation data from the Upper Pliensbachian–Lower Toarcian successions in La Cerradura and Fuente Vidriera, External Subbetic domain, Betic Cordillera (SE Spain). The obtained results indicate that these successions have low TOC contents (~ 0.3 wt.%), with TOC reaching up to 0.46 wt.% around the Polymorphum–Serpentinum ammonite zone boundary in La Cerradura. δ13CKerogen negative carbon isotope excursions (CIE) are observed at the base of the Polymorphum Zone, the Pliensbachian–Toarcian Event (Pl-Toa), and base of the Serpentinum Zone (T-OAE). Overall, the low maturity kerogen assemblages are dominated by terrestrial OM and with a minor marine component. Small increments in terrestrial OM, non-opaque phytoclasts, and palynomorphs are observed just before and during the T-OAE in the studied area. During the Early Toarcian, in the External Subbetic domain, accumulation and preservation of OM was low and with a significant terrestrial contribution, similarly to other locations around the southern margins of Iberia and Tethys. The dominance of the opaque phytoclast subgroup, the occurrence of Classopollis, and the relatively more positive δ13C of terrestrial kerogen suggest that OM was mostly sourced from an area characterised by a semi-arid climate (i.e. with pronounced arid periods) during most of the Polymorphum Zone. The T-OAE negative CIE is accompanied by an increase in terrestrial OM, with a slight increase in the non-opaque phytoclast subgroup and terrestrial palynomorph subgroup. The increase of non-opaque phytoclast and terrestrial palynomorphs are in line with the posited enhancements of the hydrological cycle and export of terrestrial OM into marine environments during the T-OAE. This study suggests a link between 13C fractionation during photosynthesis in C3 plants and climate during the Early Toarcian. This link suggests coupling of the water and terrestrial carbon cycles before and during the T-OAE. © 2019 Elsevier B.V.
英文关键词	13C fractionation; Iberian Peninsula; Organic geochemistry; Palynofacies; Pl-Toa; T-OAE
语种	英语
scopus关键词	carbon isotope; facies; geochemistry; kerogen; organic compound; organic matter; paleoenvironment; palynomorph; Pliensbachian; Toarcian; Betic Cordillera; Iberian Peninsula; Spain; Ammonoidea; Classopollis
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/150784
作者单位	MARE – Marine and Environmental Sciences Centre, Department of Earth Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal; iCRAG, Department of Geology, School of Natural Sciences, Trinity College Dublin, The University of Dublin, Ireland; Departamento de Geología and Centro de Estudios Avanzados en Ciencias de la Tierra, Universidad de Jaén, Jaén, Spain; Department of Geology, Institute of Earth Sciences, Centre for Mathematical Sciences and Nature, Federal University of Rio de Janeiro, Brazil
推荐引用方式 GB/T 7714	Rodrigues B.,Silva R.L.,Reolid M.,等. Sedimentary organic matter and δ13CKerogen variation on the southern Iberian palaeomargin (Betic Cordillera; SE Spain) during the latest Pliensbachian–Early Toarcian[J],2019,534.
APA	Rodrigues B.,Silva R.L.,Reolid M.,Mendonça Filho J.G.,&Duarte L.V..(2019).Sedimentary organic matter and δ13CKerogen variation on the southern Iberian palaeomargin (Betic Cordillera; SE Spain) during the latest Pliensbachian–Early Toarcian.Palaeogeography, Palaeoclimatology, Palaeoecology,534.
MLA	Rodrigues B.,et al."Sedimentary organic matter and δ13CKerogen variation on the southern Iberian palaeomargin (Betic Cordillera; SE Spain) during the latest Pliensbachian–Early Toarcian".Palaeogeography, Palaeoclimatology, Palaeoecology 534(2019).