Pláceres marinhos entre Caucaia e Trairi, estado do Ceará, Nordeste do Brasil

Abstract

This work studies the morphology , textural classification and heavy minerals in bottom sediments of the inner continental shelf of Ceará , between the cities of Caucaia (Fortaleza Metropolitan Region ) and Trairi. The digital model of bottom continental shelf exposed a smooth relief with the presence of irregularities between the cities Paracuru and São Gonçalo do Amarante, with a possible occurrence of paleochannel of the Curu River, the standart distribution of the average grain diameter reinforced this occurrence. Significant concentrations of heavy minerals up to 4.54 % are presents, ilmenite and tourmaline are the predominant species and showed contents over 1 Kg/ton along the São Gonçalo do Amarante coast together epidote and monazite. By chemical composition of some grains of ilmenite was possible to verify the enrichment of titanium in these weathered grains, with TiO2 content over 89 %. The study area has favorable environmental conditions to the accumulation of heavy minerals and the identified placers are considered strategic mineral resources. Besides the economic importance of these deposits is necessary to consider the fragility of the environment where they occur to minimize the impacts by marine mining activities.