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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The Mesoproterozoic to early Neoproterozoic passive margin Lajeado Group and Apiai Gabbro, Southeastern Brazil

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Author(s):
Campanha, G. A. C. [1] ; Basei, M. S. [1] ; Faleiros, F. M. [1] ; Nutman, A. P. [2, 3]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Inst Geociencias, BR-05508 Sao Paulo - Brazil
[2] Univ Wollongong, Sch Earth & Environm Sci, Wollongong, NSW 2500 - Australia
[3] Chinese Acad Geol Sci, Beijing SHRIMP Ctr, 26 Baiwzhuang Rd, Beijing 100037 - Peoples R China
Total Affiliations: 3
Document type: Journal article
Source: GEOSCIENCE FRONTIERS; v. 7, n. 4, p. 683-694, JUL 2016.
Web of Science Citations: 6
Abstract

The Lajeado Group in the Ribeira Belt, southeastern Brazil, corresponds to an open-sea carbonate platform, comprised of seven overlapping siliciclastic and carbonatic formations, intruded in its upper portion by the Apiai Gabbro. These rocks have a Neoproterozoic tectonometamorphic overprint related to arc magmatism and the Brasiliano collisional orogeny. Geochronological constraints are given by new U-Pb SHRIMP and LA-ICP-MS data for Lajeado Group detrital zircons and for magmatic zircons from the Apiai Gabbro. The youngest detrital zircons in the Lajeado Group are 1400-1200 Ma, and constrain its maximum age of deposition to be <1200 Ma, whereas the 877 +/- 8 Ma age for magmatic zircons in the Apiai Gabbro give the minimum age. Detritus source areas are mainly Paleoproterozoic (2200-1800 Ma) with some Archean and Mesoproterozoic contribution (1500-1200 Ma), with distal or tectonic stable cratonic character. The Lajeado Group should be a Stenian-Tonian carbonate platform passive margin of a continent at this time, namely the Columbia/Nuna or the Rodinia. The Apiai Gabbro displays similar age to other intrusive basic rocks in the Lajeado and Itaiacoca groups and represents tholeiitic MORB-like magmatism that we relate to the initial break-up of a Mesoproterozoic continent and the formation of the Brasiliano oceans. (C) 2015, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. (AU)