Voltar
Artigo Acesso aberto Produção Nacional
BIBTEX RIS

O GRUPO IBIÁ NA SINFORMA DE ARAXÁ: UM TERRENO TECTONOESTRATIGRÁFICO LIGADO A EVOLUÇÃO DE ARCOS MAGMÁTICOS

2000; Sociedade Brasileira de Geologia; Volume: 30; Issue: 4 Linguagem: Inglês

10.25249/0375-7536.2000304737744

ISSN

2177-4382

Autores

Hildor José Seer, Marcelo Auguste Dardenne, Márcio Martins Pimentel, Marco Antônio Fonseca, LÚCIA CASTENHEIRA MORAES,

Tópico(s)

Geography and Environmental Studies

Resumo

MAGMATIC ARCS This paper adresses new provenance data on the Ibiá metasedimentary.rocksfrom the Araxá synform.The stratigraphic type-section is locateã in Araxá region, at-the southern segment of the Brasília Belt.The Arax.4 synform is a regional fold, with WttÙ trending timbs, dipping to NNE and SSW, with a WNW gently plunging hinge.The Araxá, lbiá and Canastra groups are exposed along the limbs of thð Araxá syÅioni.Each one of these groups is placed in thiee tectonic thrust sheets,_ separated.onefrom each other by majoç gently dipping and subverticai shear zones.The lower thJust-shee't (Canastra Group) is a,psamg-pelitic metasedimentary sequence, metamorphosed up^ io gieenschist facies (chlorite and gamet zones) with Sm-Nd T., mod el age of 2.2 Ga.ltiepresents.sedimentsdeposited on a marine platfonn envirõnment.The upper thrust sheea(Araxá Group) comprises ä'ìÏetaigneor-rs mafic sequence grading to a metasedimentary rock unit, both metamorphosed up ö amphibolite facies conditionì-and cirt by granitoid rocks.The metaìedimentary rocks display S[-\dJo*.r.ngdel age of 1 .9Ga.hi the inteimediatê thrust sheet, the lbiá Group, a meta¡ielitic sequence is composed by fine grained rhythmites.Their Srñ:Nd To, model ages are between l.I and I .3Ga, and metamorphism reachei the chloi'ite zone o.f the greenschist facies.Petrographic.and.geocherñiöal data sípport an otigin due to erosional processes of N'eoproterozoic lnagmatic arcs.Sedimenti were probably deposited.from.distalturbiditic currents ii'i back-arc"basin.The Ibiá Group is so far inferpreted as a iêctonostlatigraphic terrane, with unique stratigraphy and without genetic relationships to the adjacent Canastra and Araxá terranes.

Referência(s)