Análise da ação de ácidos sobre ictiólitos da Formação Santana, Cretáceo Inferior da Bacia do Araripe, Nordeste do Brasil

Abstract

Fossils are of great importance for building knowledge of the history of life on Earth. However, it demands a careful handling from its collecting at the field to curatorship in laboratory and its incorporation in a collection. Preparation, a part of that process, evolves the removal of the fossils from the rock matrix, through mechanic and/or chemical attrition. Despite the relevance of such procedure, the access to its knowledge keeps itself relatively restricted to paleontology laboratories, lacking such type of publications. Then, this work was realized aiming to test the utilization of different types and concentrations of acids in preparation process of calcareous fossils. The tests with acetic, hydrochloric, phosphoric and sulfamic acids were executed in twelve fragments of calcareous concretions (ichthyolites) of the Santana Formation, Lower Cretaceous of the Araripe Basin. Acetic acid had showed itself the most appropriated for the treatment of calcareous concretions for its elongated and soft action.