A simple and efficient method for palynological sample preparation

Abstract

The extraction of organic microfossils is a process that requires techniques based on the elimination of the mineral components of the rock (mainly silicates and carbonates) and the subsequent concentration of the microfossils. These techniques are very diverse and have in common the dissolution of the rock (maceration) with hydrofluoric acid and concentrated hydrochloric acid to extract the organic matter, which is potentially made up of dispersed organic matter and organic walled microfossils. In this process, there are at least two fundamental objectives. First, that the process respects the fidelity of the organic microfossil record (diversity and preservation). Second, effective elimination of dispersed organic matter, obtaining the maximum concentration of microfossils and microscopic slides with a homogeneous dispersion that allows optimal observing conditions. The method described in this paper is based on a filtration process of the organic matter resulting from the maceration process, employing polyester filters and a vacuum inversion system. In the standard vacuum process, the dispersed organic matter clogs the pores of the filter. The vacuum inversion injects filtered water that unclogs the pores of the filter vessel. The alternation between normal and reverse vacuum results in the progressive elimination of the dispersed organic matter and the concentration of the organic microfossils in a rapid and non-aggressive process.