Granito Aripuanã: evidências de magmatismo rapakivi e implicações geodinâmicas mesoproterozoicas na evolução do Cráton Amazônico

Aripuanã Granite: evidence of rapakivi magmatism and mesoproterozoic geodynamic implications in the evolution of the Amazonian Craton

Abstract

The Mesoproterozoic magmatism of the southwestern Amazonian Craton, particularly associated with the Serra da Providência Suite, plays a key role in understanding the crustal and metallogenetic evolution of the region. However, it still lacks detailed studies integrating geochronology, petrography, and geochemistry. This work aims to characterize the Aripuanã Granite, located in northern Mato Grosso and within the context of the Roosevelt Group, by providing new geochronological and lithogeochemical data to contribute to the understanding of the genesis and tectonic significance of this magmatism. For this purpose, petrographic analyses of representative samples were conducted, along with U-Pb zircon dating by LA-ICP-MS and comprehensive lithogeochemical studies including major, trace, and rare earth elements. The results indicate that the Aripuanã Granite consists of rapakivitic lithotypes, with an A-type granite signature, alkaline to alkalic-calcic affinity, enrichment in incompatible elements, and negative anomalies of Sr, P, and Ti. The obtained ages (1595 ± 6 Ma to 1546 ± 6 Ma) confirm a relationship with post-collisional anorogenic events of the Mesoproterozoic, consistent with tectonic models proposed for the Rondônia Tin Province. It is concluded that the Aripuanã Granite represents a magmatic episode of mantle origin with significant crustal assimilation, acting as an important geodynamic and metallogenetic marker in the southwestern Amazonian Craton and reinforcing the potential of the Serra da Providência Suite as a reference for the study of Mesoproterozoic anorogenic magmatism in South America.