Late Barremian / Early Aptian Re–Os age of the Ipubi Formation black shales: Stratigraphic and paleoenvironmental implications for Araripe Basin, northeastern Brazil

Lúcio, Thales; Souza Neto, João Adauto; Selby, David

doi:10.1016/j.jsames.2020.102699

Late Barremian / Early Aptian Re–Os age of the Ipubi Formation black shales: Stratigraphic and paleoenvironmental implications for Araripe Basin, northeastern Brazil

Lúcio, Thales; Souza Neto, João Adauto; Selby, David

Authors

Thales Lúcio

João Adauto Souza Neto

Professor David Selby
Professor

Abstract

The Ipubi Formation of the Santana Group, Araripe Basin, Brazil, is characterized by black shales and overlying evaporite deposits and is suggested to record the transition from lacustrine to marine depositional environments. To date, the age of the black shales, constrained only by microfossils, is poorly determined, with ages spanning ∼25 myrs from 125 to 100.5 Ma (Aptian-Albian). Here we present new Re–Os elemental and isotopic data to provide the first absolute age for those rocks of the Ipubi Formation and an improved understanding of the depositional paleoenvironment of the Araripe Basin. The Re–Os isotope data for Ipubi Formation black shales yields a depositional age of 123 ± 3.5 Ma, with a highly radiogenic initial 187Os/188Os composition (Osi) of 1.97 ± 0.02. The Re–Os age indicates that the deposition of the Ipubi Formation black shales occurred during the Late Barremian/Early Aptian, prior to the onset of OAE 1a, in a highly restricted marine/lacustrine setting.

Citation

Lúcio, T., Souza Neto, J. A., & Selby, D. (2020). Late Barremian / Early Aptian Re–Os age of the Ipubi Formation black shales: Stratigraphic and paleoenvironmental implications for Araripe Basin, northeastern Brazil. Journal of South American Earth Sciences, 102, Article 102699. https://doi.org/10.1016/j.jsames.2020.102699

Journal Article Type	Article
Acceptance Date	Jun 9, 2020
Online Publication Date	Jun 18, 2020
Publication Date	2020-10
Deposit Date	Jun 18, 2020
Publicly Available Date	Jun 18, 2021
Journal	Journal of South American Earth Sciences
Print ISSN	0895-9811
Publisher	Elsevier
Peer Reviewed	Peer Reviewed
Volume	102
Article Number	102699
DOI	https://doi.org/10.1016/j.jsames.2020.102699

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© 2020 This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/