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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.)

A paleoproterozoic intra-arc basin associated with a juvenile source in the Southern Brasilia Orogen: Application of U-Pb and Hf-Nd isotopic

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Author(s):
Westin, Alice [1] ; Campos Neto, Mario C. [1] ; Hawkesworth, Chris J. [2, 3] ; Cawood, Peter A. [2] ; Dhuime, Bruno [3] ; Delavault, Helene [2]
Total Authors: 6
Affiliation:
[1] Univ Sao Paulo, Inst Geociencias, Rua Lago 562, Cidade Univ, BR-01498 Sao Paulo - Brazil
[2] Univ St Andrews, Dept Earth Sci, North St, St Andrews KY16 9AL, Fife - Scotland
[3] Univ Bristol, Sch Earth Sci, Wills Mem Bldg, Queens Rd, Bristol BS8 1RJ, Avon - England
Total Affiliations: 3
Document type: Journal article
Source: Precambrian Research; v. 276, p. 178-193, MAY 2016.
Web of Science Citations: 10
Abstract

Early Proterozoic sedimentary basins are an important record of crust generation processes and consequently a fundamental key to unraveling Earth's evolution through geological time. Sediments within the basins are typically deformed and metamorphosed by subsequent tectonothermal events, which can obliterate their links to source terranes. Nd-whole-rock and detrital zircon U-Pb and Lu-Hf isotopic analyses are among the most reliable tools to be used in provenance investigations, since zircon is a resilient mineral and the Sm-Nd system is not extensively modified during metamorphism. These methods have been applied to a study of the provenance and tectonic setting of the Sao Vicente Complex, preserved in a Neoproterozoic passive margin related allochthon within the Southern Brasilia Orogen. The complex consists of siliciclastic and calc-silicate gneisses with mafic and minor ultramafic rocks, which were deformed and metamorphosed during late Neoproterozoic collision between the Paranapanema Block and the Sao Francisco-Congo plate. Detrital zircons indicate derivation from a juvenile Paleoproterozoic source terrane (peaks of crystallization ages of ca. 2130 Ma, 2140 Ma and 2170 Ma; epsilon Hf-t between +0.1 and +6.0; NdTDM = 2.31-2.21 Ga; epsilon Nd-t = +1.6 to +2.8), with a minor contribution from older continental crust. Interlayered amphibolite rocks, with juvenile signatures (epsilon Hf-t = +5.8 to +8.2; NdTDM =2.14 and 2.30 Ga; epsilon Hf-t = +2.2 and +3.2), yielded similar ages of 2136 +/- 17 and 2143 +/- 14 Ma, suggesting syn-sedimentary magmatism. Thus, the maximum age of deposition at around 2130 Ma represents the best estimate of the depositional age of the complex. The dominance of detrital zircons ages close to the age of deposition, along with syn-sedimentary magmatism, imply a convergent margin basin tectonic environment for the Sao Vicente Complex, with similarities to fore arc basin and trench deposits. Amphibolite and meta-sedimentary rocks point to important juvenile magmatism around 2.14 Ga. juvenile Rhyacian (ca. 2.1 Ga) granite-granodiorite-tonalite orthogneisses with arc-related geochemical signatures (Pouso Alegre Complex) that override the Sao Vicente Complex, are the probable main source of detritus within the complex. Both basin and source were part of the southern edge of the Sao Francisco plate during the assembly of West Gondwana, and served as sources for early Neoproterozoic passive margin related basins. The age of intrusive anorogenic A-type Taguar granite indicates that by 1.7 Ga the Sao Vicente Complex was in a stable tectonic environment. (C) 2016 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 13/19095-1 - Processing and interpretation of U-Pb and Lu-Hf data of zircon crystals from metasedimentary and metaigneous rocks, advised by Prof. Dr. Chris Hawkesworth at the university of st. Andrews, Scotland
Grantee:Alice Westin Teixeira
Support type: Scholarships abroad - Research Internship - Doctorate
FAPESP's process: 11/13311-9 - The Carrancas Nappe System in the southern margin of the Brasilia Orogen: sedimentary provenance and tectonic setting.
Grantee:Alice Westin Teixeira
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 13/13530-8 - The orogenic margins of the Paranapanema and São Francisco blocks: from Rodinia to Gondwana
Grantee:Mario da Costa Campos Neto
Support type: Regular Research Grants