Pirambóia and Botucatu Formations Contact in the Ribeirão Preto Area.
Authors
Marcos Massoli
Departamento Estadual de Proteção dos Recursos Naturais, Secretaria do Meio Ambiente do Estado de São Paulo, DEPRN-SMA
Maria Rita Caetano-Chang
Universidade Estadual Paulista/Campus de Rio Claro.
Keywords:
arenitos conglomeráticos, leques aluviais, perfilagens geofísicas, formações Pirambóia e Botucatu.
Abstract
In water wells of the Ribeirão Preto city area was found an extensive bed of coarse to conglomeratic subfeldspathic sandstones, which show a thickness average of 30 meters. These sandstones are mostly considered to be deposited on alluvial fans, at the ending times of Pirambóia Formation sedimentation, over many areas at the central and eastern portions of São Paulo State. In the study area, these conglomeratic sandstones represent an important lithostratigraphic mark at the contact between the Pirambóia and Botucatu Formations. These rocks do not outcrop in the Ribeirão Preto city, and the present study was based on water well data from geophysical logs and well cuttings descriptions.
Keywords: conglomeratic sandstones; alluvial fans;
geophysical profiles; Pirambóia and Botucatu Formations.
