This work presents the geological mapping in the region of São Leopoldo, Novo Hamburgo and Campo Bom. Through the mapping it was possible to recognize Periano and Triassic sediments besides the volcanic rocks of the Paraná Basin. The sedimentary sequences are ordered by the lithological, textual and structural characteristics, besides the geomorphological aspects determining the stratigraphic units. The mineralogical identification was performed through x-ray diffraction. Quartz, feldspar, illite and kaolinite are the main minerals. The depositional conditions, as well as the contact relations between the sequences are presented in the paper. In the altitude around 100m the transition between the sedimentary part and the volcanic part occurs. Recent sequences are presented by sandy and clayey sections.
