O Arco Magmático Cauaburi: Revisão litoestratigráfica e sua contribuição na evolução do Domínio Imeri, Província Rio Negro, Cráton Amazônico

Abstract

Studies in Complex Cauaburi are products of regional geological surveys. Given the scarcity of structural, geochemical and metamorphic dates of Cauaburi Complex this work aimed the study of these rocks, a profile held in Rio Negro, between the cities of São Gabriel da Cachoeira and Santa Izabel do Rio Negro (AM), eastern portion Imeri Domain, in order to set parameters for distinguishing the lithofacies the Cauaburi Complex and contribute to the understanding of the evolution of Imeri Domain and Rio Negro Province. The gneiss were grouped into three lithofacies: Santa Izabel do Rio Negro, Cumati and São Jorge. Gneisses of Santa Izabel do Rio Negro and Cumati Lithofacies are metaluminous and have a calc-alkaline affinity, and the rocks of São Jorge Lithofacies are peraluminous and have an alkaline affinity. Compositionally they vary between (amphibole) -biotite granodiorite / monzogranite (lithofacies Cumati and Santa Izabel do Rio Negro) and biotite mozogranits with espessartite (São Jorge lithofacies). The geochemical signature of Cauaburi Complex is compatible with granites generated in collisional environment (magmatic arc?) and its evolution is related to 3 tectonic metamorphic distinct events: D1 responsible for generating S1 foliation during Complex Cauaburi (Cauaburi Orogeny) syntectonics emplacement; D2 responsible for S2foliation and M2metamorphism in high amphibolite facies reaching isograd of anatexis (717,9°C and 5,84 kbars) and generation and emplacement of I-type Uaupés Suite and S Içana Suite granites (Içana Orogeny) and D3 lower temperature responsible for generating the S3foliation and reworking by transcurrent shear zone in greenschist facies associated with the K'Mudku shear belt Event.