Petrografia e Mineralogia das rochas metassedimentares do furo SPD-128 do depósito de Au-Pd-Pt de Serra Pelada, Curionópolis-Pará

Abstract

The Au-Pd-Pt deposit of Serra Pelada is located near the municipality of Curionópolis, at a distance of approximately 155 km from the city of Marabá, in Pará. This deposit is located in the Carajás Mineral Province, southwest of the Amazon Craton, in the geological context of the Águas Claras Formation, belonging to the Grão-Pará Group. The deposit consists mainly of metassedimentary rocks of neoarquean age and divided into a transitional marine unit at the base and a fluvial unit at the top of the Águas Claras Formation. The metasedimentary sequence of the Serra Pelada region is composed of metarenites, metaconglomerates, ash metassiltites, carbonate metasiltites and metastylites rich in iron oxides (red beds) and all units are cut by granite intrusions of 1.88 Ga, as well as other intrusive rocks of uncertain age. In relation to structural geology, the main regional structure related to the deposit is the Serra Pelada syncline, since the mineralization occurs mainly in the joint area of this recumbent syncline. The Au-Pd-Pt deposit of Serra Pelada, as well as the drilling holes belonging to COOMIGASP - Cooperativa de Mineração dos Garimpeiros de Serra Pelada, were largely studied. However, this work has the objective of performing a more detailed study of the SPD-128 drilling hole, through petrographic analysis, mineralogical characterization and X-ray diffraction analysis. Through these analyzes, four lithologies were defined: metarenite quartzous, gray metassiltite, carbonyl metassiltite and red metassiltite, however, it was not possible to observe ore occurrence in these rocks.