The Paranapanema block is a coherent block of lithosphere located in southeastern South America spanning roughly the same area as the Paraná Basin. The existence of a tectonically stable zone beneath the Paraná Basin was first suggested in 1975. Despite difficulties in accessing the buried Paranapanema block it is inferred it must be composed mostly of orthogneiss and that it existed before the Brasiliano orogeny.[1]
Description
editParanapanema is a triangular block surrounded by structures of the Neoproterozoic Brasiliano orogeny. The northwestern edge faces the Paraguai Belt, probably the remains of an island arc from the Brazilides Ocean. On the northeast edge are the southern end of the Brasilia Belt and the Arenópolis magmatic arc. To the south and southeast are the Apiaí and São Roque belts.[2]
During the Carboniferous, Paranapanema was covered by sediments and during the Early Cretaceous, the Paraná-Etendeka large igneous province added a layer of flood basalts before the South America-Africa breakup.[2]
References
edit
- ^ Mantovani & de Brito Neves 2009
- ^ a b Mantovani et al. 2005, Definition of the Paranapanema Block, pp. 20–21
Bibliography
edit- Mantovani, M. S. M.; Quintas, M. C. L.; Shukowsky, W.; Brito Neves, B. B. (2005). "Delimitation of the Paranapanema Proterozoic block: a geophysical contribution". Episodes — Newsmagazine of the International Union of Geological Sciences. 28 (1): 18–22. Retrieved 1 August 2018.
- Mantovani, M. S. M.; de Brito Neves, B. B. (2009). "7.1 The Paranapanema Lithospheric Block: Its Nature and Role in the Accretion of Gondwana". In Gaucher, C.; Sial, A. N.; Halverson, G. P.; Frimmel, H. E. (eds.). Developments in Precambrian Geology. Vol. 16. Elsevier. pp. 257–272. doi:10.1016/S0166-2635(09)01619-3. ISBN 9780444532497.
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