NEW APPROACHES IN PALYNOLOGICAL PROCESSING: TACKLING CALCIUM FLUORIDE FORMATION: Nuevas perspectivas en el procesamiento palinológico: abordando la formación de fluoruro de calcio

Palynological processing comprises both traditional and non-traditional protocols, designed to recover representative assemblages of the depositional environments. In this context, the quality of palynological preparations is critical to ensure reliable and representative results. In this study, three different methodologies were implemented, each involving modifications to conventional palynological protocols, with the aim of removing or preventing the formation of insoluble calcium fluoride colloids generated following hydrofluoric acid treatment. The first treatment consisted of removing the already formed gel by the process of the organic residue with hydrochloric acid followed by washes with a sodium pyrophosphate solution. The second treatment included a deflocculation step using sodium pyrophosphate prior to the initial hydrofluoric treatment, modified from previously proposed protocols, in order to prevent colloid formation. The third treatment involved increasing the number of neutralization washes between acid treatments, also adapted from published palynological protocols, performing the final hydrochloric acid treatment in a heated water-bath. The results indicate that the most effective approach was to allow the formation of insoluble colloids and subsequently treat the residue with hydrochloric acid in heated water baths. In contrast, the intermediate deflocculation step, commonly recommended for such cases, proved unsuitable due to the scarce recovery of organic residue and the formation of colloids.