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|Type:||Artigo de periódico|
|Title:||Petrogenesis Of The Late Proterozoic Curaçá Mafic Dyke Swarm, Brazil: Asthenospheric Magrnatisrn Associated With Continental Collision|
|Abstract:||The late Proterozoic Curaçâ mafic dyke swarm is one of the more alkaline swaams of the Brazilian Precambrian. Intea-dyke chemical variations are characterised by higher abundances of incompatible elements in dyke margins than in the dyke centres, a feature that may have resulted from flowage differentiation, from progressive evacuation of liquids from zoned magma chambers, or possibly through dynamic melting of an uprising diapir. Inter-dyke chemical differences are best interpreted by different extents of melting of a mantle source with a small modal proportion of garnet. This source was heterogeneous and had the trace element compositions of ocean island basalts with Dupal and non-Dupa' characteristics. The emplacement of the Curaçá dykes from 650-700 Ma may have been facilitated by the extensional tectonics perpendicular to the collision zone between the São Francisco craton and the Pernambuco-Alagoas massif during the evolution of the Sergipano orogen. The energy in the system was insufficient to promote much melting of, or interaction with, the continental lithosphere or overlying crust. © 1995 Springer-Verlag.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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