Estudo da alteração eodiagenética em grãos detríticos de depósitos eólicos quaternários do porto do Pecém ( São Gonçalo do Amarante e Caucaia, CE)

Abstract

Eodiagenetic processes are the first to affect sedimentary deposits still barely buried, which can impose initial chemical modifications under detritical particles. At the Port of Pecém region (in the Cearense west coast) quaternary aeolian deposits occur from different generations and possibly affected by different processes which allow to test both the mutual influence of the same processes and that strictly related to the detritical particles from each deposit. This work aims to evaluate the eodiagenetic conditions affected by the aeolian deposits from the Port of Pecém through its influence under the detritical assemblage chemically more unstable: heavy minerals and bioclasts. Therein, sand samples are going to be collected in the different deposits and in their different soil horizons from which the bioclasts are going to be studied under magnifying glass microscope and the heavy minerals under polarized light microscope. The results from the heavy minerals analysis is going to be examined by chemical alteration indexes made by pairs of index minerals. The overall result will be assessed by statistical techniques such as linear regression and principal component analysis. The analysis under magnifying glass microscope presented carbonate bioclasts and heavy minerals. Honblende, kyanite and alterite are the minerals with the highest correlations. The general result pointed the existence of a mineral assemblage favorable to the analysis of the eodiagenetic alteration. Forthwith, the present report seeks to appraise the similarities and/or differences in the eodiagenetic alterations over the detritical particles from the aeolian deposits and their most plausible causes. Therefore, this work has the potential to assist in the comprehension of the different mechanisms of chemical alteration which have led to the formation and contrast of the dunes generation in the Cearense west coast.