THE CONTRIBUTION OF THE BARREIRAS FORMATION AS A SOURCE OF THE MANGROVE AND BOTTOM SEDIMENTS OF THE MARAPANIM RIVER IN THE REGION OF MARAPANIM (PA) BASED ON THE SIGNATURE OF HEAVY MINERALS

Abstract

The techniques of investigation of heavy minerals using new analytical instruments were used to evaluate the contribution of the Barreiras Formation sediments as source material of the sediments of the Marapanim River estuary, in the northeast of Pará: bottom sediments and muddy plains (mangroves, mainly). The most suitable granulometric fraction is very fine sand, where they stood out in decreasing order of abundance: zircon, tourmaline, staurolite, kyanite and rutile, besides sillimanite, andalusite and amphibole. The frequency of these minerals, morphological aspects, inclusions, cavities, fractures indicate that the Barreiras Formation is the main source of these minerals. However, the semi-quantitative chemical data show that there seems to be an external contribution, perhaps from the sediments of the continental platform.