Correlação entre o segmento sul da Faixa Ribeira e o segmento norte da Faixa Dom Feliciano: Integração geológico-geofísica da porção pré-cambriana do estado de Santa Catarina

Abstract

The matters surrounding the amalgamation of tectonic blocks during the Brasiliano / Pan-African orogeny have been the main subject of study of several works in recent years. However, with the increasing number of tools applied to geological knowledge, there are still several questions about the evolution of the Gondwana supercontinent yet to be answered. The main objective of this work is the hierarchy and discrimination of the boundaries between the known tectonic blocks, integrating geological and geophysical data, to better understand the importance of these large structures in the system of neoproterozoic collisions in the southern portion of Western Gondwana. In this context, it is highlighted the relationship between the deformed neoproterozoic basins during the Brasiliano orogeny and their respective relations with the Archaean / Paleoproterozoic basement, making up the Mantiqueira Province on the S / SE coast of Brazil,. The geology of the study area is dominated by precambrian terranes; Luís Alves Terrane, the vulcanosedimentary sequences of the Itajaí and Campo Alegre Basins, the metasedimentary sequences of the Brusque and Paranaguá Terranes and their granitic suites besides the granitoids of the Florianópolis Terrane. The western edge of the study area is covered by the sediments and volcanic rocks of the Paraná Basin. The shear zones and faults that separate these crustal blocks were developed during the Brasiliano / Pan-African orogenic cycle that led to the formation of the supercontinent Gondwana. These tectonic boundaries generally separate blocks of different rheology and crustal thickness. The applied methodology includes the combined analysis of field data and potential methods (magnetic and gravimetric) to create an integrated evolution model of the study area. The integration of geological and geophysical data allowed the identification of important structural lineaments and crustal boundaries. The presented geodynamic model suggests that the suture between the block composed of the Brusque, Paranaguá and Florianópolis Terranes and the block composed by the Luís Alves Terrane is the Itajaí Perimbó Shear Zone, and not the Major Gercino Shear Zone as previously suggested. Considering the Itajaí Perimbó Shear Zone as the suture zone, the metassediments of the Brusque Terrane were deposited on the basement of the Florianópolis Terrane, hereby declared as part of the Angola Craton, and are correlated to the metassediments of the Paranaguá Terrane as a passive margin that in approximately ca. 650 My became active margin, functioning as a forearc basin. The oblique collision between the blocks would have occurred with the development of a dextral transpression in the Itajaí Perimbó Shear Zone, separating the Luís Alves Terrane from the Brusque Terrane, a sinistral transcurrence represented by the Palmital Shear Zone separating the Luís Alves Terrane from the Paranaguá Terrane and a frontal thrust, represented by the Icapara and Serra Negra Shear Zones, separating the already amalgamated block from the Luís Alves and Curitiba Terranes of the Paranaguá Terrane.