Geboy, NJ, Kaufman, AJ, Walker, RJ et al. (6 more authors) (2013) Re-Os age constraints and new observations of Proterozoic glacial deposits in the Vazante Group, Brazil. Precambrian Research, 238. 199 - 213. ISSN 0301-9268
Abstract
A new Re-Os radiometric age date for an organic-rich shale horizon from the Vazante Group in Brazil, coupled with geological observations, provide evidence for late Mesoproterozoic glacial episodes, conflicting with the general view of greenhouse conditions marked by a eustatic high stand at this time. Field observations of a reverse fault juxtaposing older Mesoproterozoic sedimentary rocks above younger Neoproterozoic strata provide a new stratigraphic framework and reconcile the apparent inversion of U-Pb detrital zircon ages through the succession. Combined, the geochronological, geochemical and stratigraphic evidence suggest that the Vazante Group sediments accumulated along a passive margin of the São Francisco craton and are correlative with the neighboring Paranoá Group. Biomarker, sulfur isotope and iron speciation analyses support the interpretation of a strongly stratified water column during post-glacial transgression and deposition of one of the bituminous shale horizons. The relationship of the glaciogenic Vazante Group to other late Mesoproterozoic successions, such as the non-glacial Atar Group in West Africa and Bylot Supergroup in arctic Canada, however, remains enigmatic.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2013, Elsevier B.V. This is an author produced version of a paper published in Precambrian Research. Uploaded in accordance with the publisher's self-archiving policy |
Keywords: | Fe-speciation; Mesoproterozoic glaciation; Re-Os geochronology; Vazante Group |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 29 Sep 2014 15:35 |
Last Modified: | 16 Jan 2018 18:08 |
Published Version: | http://dx.doi.org/10.1016/j.precamres.2013.10.010 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.precamres.2013.10.010 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:80332 |