PETROGRAPHY AND DIAGENESIS OF THE CAMBAMBE BASIN, CHAPADA DOS GUIMARÃES, MATO GROSSO STATE, BRAZIL

Abstract

This work presents unpublished information on the petrography and diagenesis of the Cambambe Basin. The deposition of the Cambambe Basin started at 84 Ma ago. This basin consists of a Cretaceous volcanic-sedimentary sequence cropping out in the municipalities of Chapada dos Guimarães and Nova Brasilândia. The volcanic-sedimentary sequence starts with the magmatism of the Paredão Grande Formation at the bottom, followed by the sedimentary units Quilombinho and Cachoeira do Bom Jardim formations, which are part of the Ribeirão Boiadeiro Group and, finally, the Cambambe Formation at the top of this Cretaceous sedimentary package. This is the first detailed work on the petrography of these rocks approaching the description of litharenites, quartzarenites, sublitharenites, chert, and carbonates. The predominant cement phases are related to eodiagenesis. This work also allowed us to better understand the role tectonics has played in the deposition of the Ribeirão Boiadeiro Group and the Cambambe Formation.