Carbonate microfacies and chemostratigraphy of a late Aptian-early Albian marine distal section from the primitive South Atlantic (SE Brazilian continental margin): Record of global ocean-climate changes?

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dc.contributor.authorCaetano-Filho, Sergio [UNESP]
dc.contributor.authorDias-Brito, Dimas [UNESP]
dc.contributor.authorRodrigues, Rene
dc.contributor.authorMilward de Azevedo, Ricardo Latge
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUniversidade do Estado do Rio de Janeiro (UERJ)
dc.contributor.institutionPetrobras SA
dc.date.accessioned2018-11-26T15:44:10Z
dc.date.available2018-11-26T15:44:10Z
dc.date.issued2017-06-01
dc.description.abstractLate Aptian-early Albian limestones from the eastern Brazilian continental margin record the early evolution of the South Atlantic Ocean. In Tethyan and North Atlantic domains, a planktic foraminiferal turnover and organic-rich deposits related to Oceanic Anoxic Event lb (OAE lb) point to major ocean climate changes through this interval. Coeval organic-rich deposits of the South Atlantic Ocean have been interpreted as the product of restricted circulation rather than attributed to a global event. However, previous investigations of the early marine phase of South Atlantic lack data from more distal facies, making correlations to global events difficult. Here, we present C, O, and Sr isotopes, elemental geochemistry, TOC and pyrolysis data, as well as a microfacies analysis of an upper Aptian-lower Albian distal section from the Campos Basin (southeastern Brazil). Our focus is on the paleoenvironmental characterization of and the possible association between organic-rich deposits and major perturbations related to Aptian-Albian transition. Five microfacies associations (MA) were identified in the informal units I and III, which were deposited in the neritic region on a carbonate ramp. Organic-rich deposits were described in unit III, composed of planktic-dominated wackestones interbedded with black shales, in a distal dysoxic to anoxic environment. The carbonates Sr-87/Sr-86 ratios showed a drastic increase (0.7072-0.7074), interpreted as enhanced chemical weathering, supported by the increase of continental input to the top of section. This trend was accompanied by a long-term delta C-13(carb) negative excursion, which were assigned to the latest late Aptian-early Albian interval of the isotope reference curves, in accordance with the described occurrence of Colomiella recta. This scenario matches those proposed for the late Aptian-early Albian transition and OAE lb set, as an enhanced greenhouse stage, pointing to the influence of the referred ocean-climate changes on the deposition of organic-rich deposits of the early South Atlantic Ocean. This investigation gives more evidences that these perturbations were a widespread event, as a product of broad-scale disturbances in the global carbon cycle which also controlled organic deposition and preservation on restricted settings. (C) 2017 Elsevier Ltd. All rights reserved.en
dc.description.affiliationUniv Estadual Paulista, UNESPetro, Ctr Geociencias Aplicadas Petr, BR-13506900 Rio Claro, SP, Brazil
dc.description.affiliationUniv Estado Rio de Janeiro, Fac Geol, BR-20550900 Rio De Janeiro, RJ, Brazil
dc.description.affiliationPetrobras SA, Rio De Janeiro, RJ, Brazil
dc.description.affiliationUnespUniv Estadual Paulista, UNESPetro, Ctr Geociencias Aplicadas Petr, BR-13506900 Rio Claro, SP, Brazil
dc.description.sponsorshipproject Carbonate rocks of the Cretaceous of Brazil
dc.description.sponsorshipUNESP
dc.description.sponsorshipAdali Spadini (PETROBRAS)
dc.description.sponsorshipPETROBRAS
dc.format.extent23-44
dc.identifierhttp://dx.doi.org/10.1016/j.cretres.2017.02.011
dc.identifier.citationCretaceous Research. London: Academic Press Ltd- Elsevier Science Ltd, v. 74, p. 23-44, 2017.
dc.identifier.doi10.1016/j.cretres.2017.02.011
dc.identifier.fileWOS000400215200003.pdf
dc.identifier.issn0195-6671
dc.identifier.urihttp://hdl.handle.net/11449/159530
dc.identifier.wosWOS:000400215200003
dc.language.isoeng
dc.publisherElsevier B.V.
dc.relation.ispartofCretaceous Research
dc.relation.ispartofsjr0,835
dc.rights.accessRightsAcesso aberto
dc.sourceWeb of Science
dc.subjectOAE lb
dc.subjectAptian
dc.subjectAlbian
dc.subjectSr-isotope stratigraphy
dc.subjectC-isotope stratigraphy
dc.titleCarbonate microfacies and chemostratigraphy of a late Aptian-early Albian marine distal section from the primitive South Atlantic (SE Brazilian continental margin): Record of global ocean-climate changes?en
dc.typeArtigo
dcterms.licensehttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dcterms.rightsHolderElsevier B.V.

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