Lithofacies and paleoenvironmental significance of the Itararé sediments in the middle Tietê valley, State of São Paulo

Abstract

This paper deals with lithological description and comparisons of cores from six thoroughly cored groundwater wells. They range in depth from 101,4 to 310m. They were drilled between the years 1985 and 1990, near the towns of Capivari and Rafard, in the middle Tietê river valley, State of São Paulo, Brasil, by the "Instituto Geológico, Secretaria do Meio Ambiente". The drilled sediments are Permian in age and belong to the Permo-Carboniferous Itararé Subgroup. Seven additional wells in the middle Tietê valley, also drilled between 1985 and 1990 by the "Instituto Geológico", are referred to but not described. The interpretation of the lithologies and sedimentary structures of these sediments as well as addicional data from field researches allow a paleogeographic interpretation and reconstruction of the environments of deposition, in Permian times, around the Capivari and Rafard urban areas. A sea would have been persistently present in the area, its sediments being laid down in offshore and submarine fan conditions.