Novas proposições metodológicas para o calcímetro de bernard e caracterização dos sedimentos marinhos do Espírito Santo

Abstract

The Espírito Santo marine area comprises two sedimentary basins of great economic importance for the country: the Campos basin and the Espírito Santo basin. With this in mind, the present study carried out a sedimentological analysis of the region, through samples that were collected on continental shelf, slope and continental rise. Grain size analysis and measurements of organic matter content and calcium carbonate were made. In general, the studied region presented a great concentration of carbonate sediments, especially in greater depths. The granulometric distribution obeys a depth gradient, and the continental shelf being almost entirely composed of sand, while there is a predominance of silt and clay in the slope and continental rise of the studied area. The highest levels of organic matter are associated with loamy sediments. For the analysis of calcium carbonate content, a new methodological proposal was developed to improve the performance of the modified Bernard calcimeter, widely used in sediments studies in Ceará. The following validation tests were applied to the new methodology and they were suggested by INMETRO: linearity, working range, sensitivity, specificity, precision, recovery and robustness. The tests were performed through spiked samples, and results indicated that the rectified method presents adequate standards according to the Institute of Metrology norms.