Porto Primavera Ichnofossil Geosite, Brazil: Geoconservation Measures in a Protected Area

Abstract

Porto Primavera geosite comprises aeolian sandstones with tetrapod trace fossil cropping out at the Porto Primavera Hydroelectric Power Plant, São Paulo State, Brazil. The Upper Cretaceous Rio Paraná Formation, which contains these tracks, is composed of medium–fine quartzarenites well- sorted and supermature, with typically large tabular/trough cross-bedding. They accumulated in complexes of large barchanoid dunes, moved by winds to the south-west. The Porto Primavera association consists of tracks of theropod dinosaurs and small mammals preserved in concave epirelief. These rare records in aeolian desert environments from the Late Cretaceous of Brazil indicate that even the interior Caiuá desert was occupied by organisms. The study focused on the characterization of the ichnofossils, assessing their susceptibility to degradation by natural and anthropogenic processes, and proposing measures to manage the geosite. Because the risk of degradation of the geosite is high, it is proposed that prior to their removal the slabs should be replaced with synthetic resin replicas made using silicone rubber moulds. The sense of disconnection between the objects and their natural geological context could be addressed by depositing the objects near the geosite in the Museum of Regional Memory. The geosite is indicated as a new holostratotype to the Rio Paraná Formation.