Potential flare-ups and lulls in the multi-stage magmatism of the Dom Feliciano belt, southern Brazil: Evidence from geochemistry and isotopic data

Author(s)

da Cruz, Rodrigo Fabiano ; Basei, Miguel Angelo Stipp ; Philipp, Ruy Paulo

• Document type: Journal article
• Source: Journal of South American Earth Sciences; v. 123, p. 18-pg., 2023-01-26.

Abstract

The genesis of Precambrian granitic batholiths related to supercontinent assembly is controversial, especially regarding their generating processes and tectonic settings. The present study focused on the Pelotas Batholith (Magmatic-arc domain) of the Dom Feliciano Belt, which comprises the southern segment of the Mantiqueira Province in southeastern South America. New U-Pb and Lu-Hf zircon data from plutonic rocks with evidence of magma mixing and mingling, as well as assimilation of wall rocks, suggest multi-stage magmatism related to flare-up episodes of intense magmatism, potentially triggered by changes in the tectonic setting. U-Pb zircon analyses yielded crystallization ages of granodioritic gneiss xenolith at 691.5 +/- 7 Ma, microgranodiorite xenolith at 645.9 +/- 3.7 Ma, host monzogranite at 634.4 +/- 4.4 Ma, and intrusive syenogranite at 620.1 +/- 4.7 Ma, all intruded by syenogranitic pegmatite at 606.9 +/- 1.7 Ma. Other analyses were performed on calc-alkaline granite (633 +/- 4 Ma) and peraluminous granite (609.6 +/- 2.2 Ma). The Lu-Hf data highlights a model age interval ranging from 1.7 to 1.3 Ga with epsilon Nd values between-4 and 1, except for the pegmatite sample which also includes Paleoproterozoic and Archean model ages (3.3-1.6 Ga) and epsilon Nd values between-33 and-1. Furthermore, the acquired data, together with the gathered dataset Dom Feliciano Belt granites, emphasizes a contribution from slightly juvenile to crustal sources, with model ages ranging primarily from Statherian-Orosirian to Mesoproterozoic. Signature patterns are consistent with sources from African basement rocks. (AU)

• 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