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| PIMENTEL,MÁRCIO M.; BOTELHO,NILSON F.. |
| Supracrustal rocks of the Araí Group, together with coeval A-type granites represent a ca. 1.77-1.58 Ga old continental rift in Brazil. Two granite families are identified: the older (1.77 Ga) group forms small undeformed plutons, and the younger granites (ca. 1.58 Ga) constitute larger, deformed plutons. Sr-Nd isotopic data for these rocks indicate that the magmatism is mostly product of re-melting of Paleoproterozoic sialic crust. Initial Sr ratios for both granite families are ca 0.726 and 0.720. Most TDM model ages are between 2.58 and 1.80 Ga. epsilonND(T) values are between +3.6 and -11.9. Araí volcanics are bimodal, with basalts and dacites/rhyolites interlayered with continental sediments. The felsic volcanics show Nd isotopic characteristics which... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sr-Nd isotopes; Paleoproterozoic; Tin granites; Transamazonian. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652001000200010 |
