A technique for disaggregating sedimentary rocks in order to recover vertebrate fossils in the Adamantina and Marília formations (Bauru Group, Upper Cretaceous)

Abstract

Accumulations of vertebrate fossils found in the Bauru Group (Late Cretaceous) of the Triângulo Mineiro region have been traditionally collected by nonstandardized field methods. However, the lack of specific protocols for collecting micro and macrovertebrates has sometimes resulted in questionable datasets and misinterpretations. In order to recover fossils more effectively, in this study we used a method that involves the collection of sediment, gentle chemical disaggregation, and subsequent total screenwashing of a large volume of rocks. This method was applied to sedimentary rocks bearing fossil fragments of the Marília and Adamantina formations. Results show that the chemical treatment can contribute to a better disaggregation of rocks in order to recover small fossil fragments and microfossils without damaging their features. This method can be applied at other localities containing fossil fragments or microfossils of vertebrates.