An Unusual Fossiliferous Site in the Romualdo Formation in the Socorro Basin (Northeast Brazil)

Abstract

The Santana Group, from the base to the top, comprises the Barbalha, Crato, Ipubi, and Romualdo formations. Calcareous concretions from the Romualdo Formation are found in the Araripe Basin, but the geographic extension of this sequence has evidence in the Socorro Basin on the border of the state of Pernambuco; however, these areas outside of the Araripe Basin have rarely been investigated. The purpose of this research was to carry out a data survey of fossils collected in the Romualdo Formation from the Socorro/Santo Ignácio Basin area that were found in the northeastern portion of Ouricuri municipality in the state of Pernambuco; a new fossiliferous site, known as the Cara Branca site, is reported. Samples were collected from the surface and often in the off-season. This area is cleared by tractors for planting, either exposing fossils or moving some of the fossils. This disturbance reinforces the need for fossil rescues and excavations in this area, where weathering, agricultural machinery, and erosion can damage the fossil record. According to the initial paleontological sampling, the obtained taphonomic information pointed to rapid burial, and the degrees of disarticulation observed in some specimens indicated that disarticulation occurred through necrolysis.