A field guide to the sand-rich turbidite systems of the Taciba Formation, Itararé Group, Paraná basin, Brazil

Abstract

This field guide provides a detailed outcrop logistics, access and description of the sand-rich turbidite deposits of the Taciba Formation (Rio do Segredo Member), the uppermost unit of the Pennsylvanian Itararé Group (Paraná Basin), which crops out in the Santa Catarina State, southern Brazil. This area has become a classic destination for professional’ field courses and students interested in outcrop analogous to offshore turbidite reservoirs. Although some of the outcrops have been widely described, some localities remain unexplored. These turbidite systems are here subdivided on the basis of their degree of confinement, relative to the Precambrian basin floor topography. The bedrock morphology was shaped during the Late Paleozoic Ice Age. Advance and retreat phases of glaciers are represented by superficial scouring into the crystalline basement. This glacially-carved topography in turn controlled the subsequent sedimentation by forming a basal nonconformity in the Taciba Formation. Thus, the turbidity currents and their deposits, exposed in three main areas along the eastern margin of the Paraná basin, were classified as confined and/or unconfined. This field guide is also valuable for nourishing the ongoing debate on the turbidity currents interpretations based on sedimentological descriptions of the main localities and their major features. Field guides are quite popular in North America and Europe, among other places, but not so popular in Brazilian literature. The present contribution aims to bring details on some little known turbidite-outcropping localities of the Taciba Formation. It also intends, through its format, to attract interest the of national and international geologists on Brazilian key outcrops and offer a synthesis and a starting point for teaching purposes and future studies.

Keywords

• Late Paleozoic
• reservoir analogues
• outcrops
• confined
• unconfined