Structural context of the guapiara topographic map area

Abstract

The Guapiara Topographic Map 1:50,000 is located in the southernmost part of the state of São Paulo and comprises the northern portion of the Apiaí Terrain, of meso-to neoproterozoic age, inserted in the central-southern zone of the Ribeira Belt of the Mantiqueira Central Province. The region is characterized by the rocks of the metavolcanic/metasedimentary sequence of the Açungui Supergroup, defined by the Água Clara Formation and the Votuverava and Itaiacoca groups, as well as granite bodies of the Três Córregos Granite and the Capão Bonito Granite, sedimentary rocks of the Itararé Group, basic intrusive associated to the Serra Geral Magmatism and quaternary sediments. The structural framework is dominantly determined by the neoproterozoic tectonic arrangement. The rocks present a structural evolution of the polyphase type, evidenced by the superposition of events of mainly four deformation phases Dn, Dn+1, Dn+2 and Dn+3. The two initial events are related to a tectonic thrust, NE/SW and NW/SE direction, respectively, accompanied by genetically associated structures, such as thrust faults, folds and Sn and Sn+1 foliations. Superimposing to these structures, two events Dn+2 and Dn+3 occur, connected to the final collision phase and a strike-slip/transpressive tectonic. This event is responsible for the folding of the pre-formed structures, with the direction of axial plane being NE/SW and NW/SE, respectively.