The Cauaburi magmatic arc: Litho-stratigraphic review and evolution of the Imeri Domain, Rio Negro Province, Amazonian Craton

摘要

A lithostratigraphic review of the Cauaburi Complex was carried out by means of field, tectonometamorphic and geochemical data, which were the basis for the sub-division of the Cauaburi Complex orthogneisses into the Santa Izabel do Rio Negro, Cumati and Sao Jorge facies. These rocks crop out between Sao Gabriel da Cachoeira and Santa Izabel do Rio Negro, Amazonas, Brazil. The gneisses of the Santa Izabel do Rio Negro and Cumati facies are metaluminous and of calc-alkaline affinity; in turn, the rocks of the Sao Jorge facies are peraluminous and of alkaline affinity. They vary from (amphibole)-biotite granodiorites/monzogranites (Cumati and Santa Izabel do Rio Negro fades) to spessartite-bearing biotite monzogranites (Sao Jorge fades). The Cauaburi Complex geochemical signature is compatible with that of granites generated in collisional settings (magmatic arc?) and its evolution is related to three distinct tectono-metamorphic events: D1, causing foliation S-1, which developed during the Cauaburi Complex syn-tectonic emplacement in the Cauaburi Orogeny; D-2/M-2, causing foliation S-2, which was generated under amphibolite fades conditions (717.9 degrees C and 5.84 kbars), and the emplacement of I-and S-type granite during the Icana Orogen, and low temperature D-3, associated with the K'Mudku Event, which caused foliation S-3 and reworking via transcurrent shear zones under greenschist facies conditions. 2017 Elsevier Ltd. All rights reserved.