Nota explicativa do mapa geológico da Formação Camarinha Formation - PR

Abstract

The Camarinha Formation (central-eastern part of the State of Paraná, southern Brazil) is a late Proterozoic unit which has a faulted and discordant contact with older Proterozoic metasedimentary rocks of the Ribeira Belt (Água Clara, Votuverava and Capiru formations), close to the Atuba, Betara and Três Córregos complexes. On its western side, it is unconformably covered by Devonian basal strata of the Paraná Basin (Furnas Formation). The Camarinha Formation consits of poorly sorted immature rocks, such as conglomerates, breccias, sandstones, siltstones, mudstones and rhytmites, grouped into three units (A, B, and C) with transitional contacts. A and C units are sandy and muddy, and B unit is conglomeratic. These units were deposited by processes that are common in prograding and retrograding fans in coastal environments (fandeltas). The source areas are represented by the Água Clara, Votuverava and Capiru formations, and Atuba and Três Córregos complexes. The basin was formed in a late-to-post orogenic environment related to the Brasiliano Orogeny, just before post-orogenic alkaline magmatic intrusions and volcanic-sedimentary rocks of the Castro and Guaratubinha basins. The rocks of Camarinha Formation are deformed related to the Lancinha Shear Zone, whose right-lateral movement generated associated folds and fractures. The formation is preserved as remains of the original basin, in two folded zones forming synclines, one of which is related to the Lancinha Shear Zone. The original borders of the basin are not preserved.