Time constraints on magmatism along the Major Gercino Shear Zone, southern Brazil: implications for West Gondwana reconstruction

Chemale, Farid, Mallmann, Guilherme, de Fátima Bitencourt, Maria and Kawashita, Koji (2012) Time constraints on magmatism along the Major Gercino Shear Zone, southern Brazil: implications for West Gondwana reconstruction. Gondwana Research, 22 1: 184-199. doi:10.1016/j.gr.2011.08.018


Author Chemale, Farid
Mallmann, Guilherme
de Fátima Bitencourt, Maria
Kawashita, Koji
Title Time constraints on magmatism along the Major Gercino Shear Zone, southern Brazil: implications for West Gondwana reconstruction
Journal name Gondwana Research   Check publisher's open access policy
ISSN 1342-937X
Publication date 2012
Sub-type Article (original research)
DOI 10.1016/j.gr.2011.08.018
Open Access Status
Volume 22
Issue 1
Start page 184
End page 199
Total pages 16
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Abstract The Dom Feliciano Belt, situated in southernmost Brazil and Uruguay, contains a large mass of granite-gneissic rocks (also known as Florianópolis/Pelotas Batholith) formed during the pre-, syn- and post-orogenic phases of the Brasiliano/Pan-African cycle. In the NE extreme of this granitic mass, pre-, syn- and post-tectonic granites associated with the Major Gercino Shear Zone (MGSZ) are exposed. The granitic manifestation along the MGSZ can be divided into pre-kinematic tonalitic gneisses, peraluminous high-K calc-alkaline early kinematic shoshonitic, and metaluminous post-kinematic granites. U-Pb zircon data suggest an age of 649. ±. 10. Ma for the pre-tectonic gneisses, and a time span from 623. ±. 6. Ma to 588. ±. 3. Ma for the early to post-tectonic magmatism. Negative . εHf (. t) values ranging from -. 4.6 to -. 14.6 and Hf model ages ranging from 1.64 to 2.39. Ga for magmatic zircons coupled with whole rock Nd model ages ranging from 1.24 to 2.05. Ga and εNd (. t) values ranging from -. 3.84 to -. 7.50, point to a crustal derivation for the granitic magmatism. The geochemical and isotope data support a continental magmatic arc generated from melting of dominant Paleoproterozoic crust, and a similar evolution for the granitic batholiths of the eastern Dom Feliciano Belt and western Kaoko Belt.
Keyword Dom Feliciano Belt
Isotope geochemistry
Neoproterozoic magmatism
Pan-African/Brasiliano orogeny
Strike-slip shear zones
U-Pb zircon geochronology
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Earth Sciences Publications
 
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