Tracing the history from Rodinia break-up to the Gondwana amalgamation in the Embu Terrane, southern Ribeira Belt, Brazil

Author(s)

Passarelli, Claudia R. ^[1] ; Verma, Sanjeet K. ^[2] ; McReath, Ian ^[1] ; Basei, Miguel A. S. ^[1] ; Siga, Jr., Oswaldo ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Geociencias, Rua Lago 562, BR-05508080 Sao Paulo, SP - Brazil

^[2] Inst Potosino Invest Cient & Tecnol, Div Geociencias Aplicadas, Col Lomas 4a Sec, San Luis Potosi 78216 - Mexico

• Document type: Journal article
• Source: LITHOS; v. 342, p. 1-17, OCT 2019.
• Web of Science Citations: 1

Abstract

The Mantiqueira Province (MP) is the major tectonic unit of southern Brazil, resulting from the closure of the Adamastor Ocean during Gondwana assembly. The Ribeira Belt (RB), the largest domain of the MP, has developed in several episodes of convergence during the Brasiliano-Pananafricano Orogeny and is subdivided into several terranes. One of them is the Embu Terrane (ET) that hosts metasedimentary successions and granitic bodies of different tectonic contexts. A combined study of petrography, geochemistry, LA-ICP-MS zircon U-Pb dating, and Hf isotope geology was carried out on the Juquia (JG) and Sete Barras (SBG) granites of the southeastern ET, hosted by metasupracrustal rocks. The JG yielded U-Pb zircon ages of 799 +/- 5 Ma and 755 +/- 3 Ma, while the SBG U-Pb zircon and monazite ages of 602 +/- 2 Ma and 598 +/- 2 Ma respectively. Both granites have Neoarchean/Paleoproterozoic Hf (T-DM) model ages and strongly negative epsilon Hf-(t) values in zircon. Whole rock isotopic data support an evolved crustal signature, pointing to sources of long-lived crustal residence. The JG is a ferroan calc-alkalic peraluminous two-mica granite, while the SBG is a ferroan alkali-calcic peraluminous two-mica granite. The acquired data disclose two distinct magmatic episodes in ET: the Tonian Juquia magmatism took place during the final stages of the Rodinia breakup or initial stages of expansion of one of the hypothetical oceans in the region and the Ediacaran Sete Barras magmatism might have been formed at the local transtensional area during final West Gondwana amalgamation. The data presented here and the wide-ranging geochronological data assemblage from the RB allowed a new paleogeographic reconstruction of the West Gondwana assembly. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/24316-7 - Isotope-geochronological study and petrogenetic evolution of the magmatism of the Mongagua domain - coastal Terrane-SE of the State of São Paulo, Brazil
• Grantee: Cláudia Regina Passarelli
• Support Opportunities: Regular Research Grants
• FAPESP's process: 15/03737-0 - The Rio de La Plata Craton and the Western Gondwana Assembly
• Grantee: Miguel Angelo Stipp Basei
• Support Opportunities: Research Projects - Thematic Grants