| Full text | |
| Author(s): |
Teixeira, W.
[1]
;
Avila, C. A.
[2]
;
Dussin, I. A.
[3]
;
Correa Neto, A. V.
[4]
;
Bongiolo, E. M.
[4]
;
Santos, J. O.
[5]
;
Barbosa, N. S.
[6]
Total Authors: 7
|
| Affiliation: | [1] Univ Sao Paulo, Inst Geociencias, BR-05508080 Sao Paulo - Brazil
[2] Univ Fed Rio de Janeiro, Museu Nacl, Rio De Janeiro, RJ - Brazil
[3] Univ Sao Paulo, Inst Geociencias, FAPESP, BR-05508080 Sao Paulo - Brazil
[4] Univ Fed Rio de Janeiro, Inst Geociencias, Rio De Janeiro, RJ - Brazil
[5] Univ Western Australia, Ctr Explorat Targeting, Nedlands, WA 6009 - Australia
[6] Univ Sao Paulo, Inst Geociencias, Grad Program, BR-05508080 Sao Paulo - Brazil
Total Affiliations: 6
|
| Document type: | Journal article |
| Source: | Precambrian Research; v. 256, p. 148-169, JAN 2015. |
| Web of Science Citations: | 54 |
| Abstract | |
Zircon U-Pb-Hf and geochemical data provide new clues for a juvenile ITG segment in the Mineiro belt, outlined by published information about the nearby 2.35 Ga Lagoa Dourada suite. The Resende Costa Orthogneiss and coeval rocks yield U-Pb crystallization ages from 2351 +/- 48 to 2317 +/- 16 Ma and coherent Sm-Nd T-DM ages between 2.3 and 2.5 Ga. These rocks show epsilon(Nd(2.35Ga)) and epsilon(Sr(2.35Ga)) values that suggest derivation from a short-lived, slightly depleted source akin to products of island arcs, whereas the geochemistry is consistent with a tholeiitic source with minor crustal assimilation. The positive to negative zircon epsilon(Hf(2.35Ga)) suggests the subordinate involvement of crustal components during the hypothesized c. 2.35 Ga slab subduction event. In a similar manner, metabasalts (lower unit) of the adjoining Congonhas-Itaverava belt show Nd-Sr isotopic and chemical constraints indicating derivation from an early Paleoproterozoic tholeiitic source subjected to crustal assimilation. A coeval metagraywacke from the upper unit yields U-Pb zircon detrital ages as young as 2349 + 14 Ma suggesting the maximum depositional age for the precursor basin (foreland setting?) whilst most of the grains indicate contribution from nearby Archean sources. The Resende Costa-Lagoa Dourada rocks characterize the precocious arc magmatism of the Minas accretionary orogeny. This composite orogeny created the Mineiro belt and the adjoining Mantiqueira and Juiz de Fora belts in the 2.35-2.00 Ga interval. Due to such a polycyclic framework the Resende Costa Orthogneiss and coeval rocks show multiple metamorphic overprints dated at 2140 and 2050 Ma. The new and compiled data and regional geologic correlations provide evidence for a growing Paleoproterozoic landmass in the South America continent. (C) 2014 Elsevier B.V. All rights reserved. (AU) | |
| FAPESP's process: | 09/53818-5 - Caracterização tectônica dos greenstore belts Rio das Mortes, Nazareno e Dores de Campo: implicações para a evolução crustal do cinturão mineiro |
| Grantee: | Wilson Teixeira |
| Support Opportunities: | Regular Research Grants |