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| Format: | Artículo científico |
| Language: | en |
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Academia Brasileira de Ciências
2003
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| Online Access: | https://www.redalyc.org/articulo.oa?id=32775111 |
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Table of Contents:
- Shrimp and conventional U-Pb age, Sm-Nd isotopic characteristics and tectonic significance of the K-rich Itapuranga suite in Goiás, Central Brazil Elton L. Dantas Richard A. Armstrong Reinhardt A. Fuck Márcio M. Pimentel Multidisciplinaria (Ciencias Naturales y Exactas) Uruana Pb SHRIMP Brasiliano Itapuranga Brasília Belt The Itapuranga alkali granite and Uruana quartz syenite are large K-rich EW-elongated intrusions, in thecentral part of the Neoproterozoic Brasília Belt, central Brazil. They are associated with Pireneus lineaments,which cut the regional NNW-SSE structures of the southern part of the belt.SHRIMP and conventional U-Pb data for the Itapuranga and Uruana intrusions indicate crystallization agesof 624 ± 10 Ma and 618 ± 4 Ma, respectively. Three zircon cores from the Itapuranga granite yielded U-Pbages between 1.79 and 1.49 Ga. Sm-Nd TDM ages for both intrusions are 1.44 Ga and εNd(T) values are5.1 and 5.7, suggesting the input of material derived from older (Paleo- to Mesoproterozoic) sialic crustin the origin of the parental magmas.Magma mixing structures indicate co-existence of mafic and felsic end-members. The felsic end-memberof the intrusions is dominantly represented by crust-derived melts, formed in response to the invasion ofPaleo/Mesoproterozoic sialic crust by alkali-rich mafic magmas at ca. 620 Ma.These intrusions are roughly contemporaneous with, or perhaps slightly younger than, the peak of regionalmetamorphism in the southern Brasília Belt. Their emplacement along the Pireneus lineament suggest asyn-tectonic origin for them, most probably in transtensional settings along these faults. 2003 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32775111 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.1 Vol.75