The Itararé Group in the region of Itu, State of São Paulo: intense glacial erosional and depositional processes

Abstract

The Itararé Group, Neopaleozoic (Mississippian-Pennsylvanian) of the Paraná Basin, is exposed in a large area of the eastern part of State of São Paulo, predominantly overlying Precambrian rocks. Although of distinctive nature, the areas named here Itu and Salto, are notable for the abundance of glacial records. As a contribution to paleoenvironmental reconstructions, this paper analyzes the glacial features present in these areas, starting from previous studies and including new observations of a sedimentary front exposed in the Colonial Quarry. The Salto area stands out for the evidences of strong glacial erosive action, such as roches moutonnées, which are only found in this region in Brazil, and striated pavements, associated with tillites, diamictites and glacial aqueous deposits that reach up to 8 m in thickness. Contrastingly, thick glacial aqueous deposits reaching 300 m in thickness stand out in the Itu area, with subordinate tillites and diamictites.