Produção Nacional
GEOCRONOLOGIA Rb-Sr E Sm-Nd DA INTR USÃO MÁFICO- ULTRAMÁFICA A CAM AD AD A DE CANA BRAVA, BRASIL, E CONSIDERAÇÕES SOBRE SUA EVOLUÇÃO TECTÔNICA
2017; Sociedade Brasileira de Geologia; Volume: 27; Issue: 2 Linguagem: Inglês
ISSN
2177-4382
AutoresCiro Teixeira Correia, Vicente Antônio Vitório Girardi, Colombo Celso Gaeta Tassinari, Hardy Jost,
Tópico(s)Paleontology and Stratigraphy of Fossils
ResumoThe Cana Brava complex is an anorogenic stratiform complex, whose layers dip from 30° to 50° NW. The massif is made up of five units composed of layers containing several associations of cumulus phases and variable amounts of inter-cumulus minerals. Transition between units are characterized by abrupt changes in the composition of these phases. From base to top, the sequence consists of amphibolites (PICB1), overlain by serpentinites (PICB2), metawebsterites (PICB3), and metagabbros (PICB4 and PICB5). This sequence was originally formed by microgabbros, peridotites, websterites, and gabbros. Isotopic data indicate that the parental magma of the Cana Brava complex evolved as follows: (a) Mantle derivation at about 2.5 Ga and subsequent retention at subcrustal levels; (b) Intrusion within the Palmeiropolis volcano-sedimentary sequence and igneous crystallization at about 2.0 Ga; (c) Metamorphism and ductile-ruptile deformation under compression at about 1.3 Ga; and (d) Further metamorphic reequilibration during the Brasiliano Cycle at about 0.77 Ga.
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