Recurring extensional and strike-slip tectonics after the Neoproterozoic collisional events in the southern Mantiqueira province

Anais da Academia Brasileira de Ciências

Renato P. Almeida²  Maurício G. M. Santos¹  Antonio R.s. Fragoso-cesar²  Liliane Janikian¹  Gelson L. Fambrini¹ 

[1],Universidade de São Paulo Instituto de Geociências Departamento de Geologia Sedimentar e AmbientalSão Paulo SP ,Brasil

关键词: Camaquã Basin;    Earth Sciences;    Neoproterozoic;    Paleostress Analysis;    Rift Basin;    Southern Brazil;    Bacia do Camaquã;    Ciências da Terra;    Neoproterozoico;    Análise de Paleotensões;    Bacia Rift;    Sul do Brasil;   

DOI  :  10.1590/S0001-37652012005000034

来源: SciELO

【 摘 要 】

In Eastern South America, a series of fault-bounded sedimentary basins that crop out from Southern Uruguay to Southeastern Brazil were formed after the main collisional deformation of the Brasiliano Orogeny and record the tectonic events that affected the region from the Middle Ediacaran onwards. We address the problem of discerning the basin-forming tectonics from the later deformational events through paleostress analysis of more than 600 fault-slip data, mainly from the Camaquã Basin (Southern Brazil), sorted by stratigraphic level and cross-cutting relationships of superposed striations, and integrated with available stratigraphic and geochronological data. Our results show that the Camaquã Basin was formed by at least two distinct extensional events, and that rapid paleostress changes took place in the region a few tens of million years after the major collision (c.a. 630 Ma), probably due to the interplay between local active extensional tectonics and the distal effects of the continued amalgamation of plates and terranes at the margins of the still-forming Gondwana Plate. Preliminary paleostress data from the Castro Basin and published data from the Itajaí Basin suggest that these events had a regional nature.

【 授权许可】

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