New Method of Rock Samples Preparation for Palynological and Palynofaciological Analysis

Resumo

This paper describes a new chemical sample preparation methodology for palynological analysis with the concentration of particulate organic material. To demonstrate the method potentiality, chemical experiments were carried out on representative rock samples composed of different lithologies, environments, and ages, from five Brazilian basins. Five sedimentary samples were taken from subsurface being four from the core and one cutting, and additionally one from outcrop, making six samples. The experiments aimed to authenticate the effectiveness of using the Fluoclor chemical reagent to replacing hydrofluoric acid (HF) ordinarily used in the preparation of palynological samples. HF acid, in Brazil, has its trade restricted and controlled by the army, making its continual acquisition impossible. Because it is a chemical compound by combining hydrofluoric acid (HF) with a small addition (~ 13%) of hydrochloric acid (HCl), it is free of this control, making routine palynological samples processing method possible. To illustrate the product efficacy, tests were performed on sediments of different ages (Paleozoic, Mesozoic, and Cenozoic) and with diverse mineralogical compositions. The data obtained attended as a comparison with the same stratigraphic intervals samples, previously processed with hydrofluoric acid (HF). The results showed that, regardless of both the stratigraphic interval analyzed and the mineralogical composition of the samples, the percentage recovery of the organic groups, as well as the marine and non-marine palynomorphs, were equivalent, thus demonstrating the reliability of the new method for chemical processing palynological samples.