Voltar
Artigo Acesso aberto Produção Nacional
BIBTEX RIS

VULCANISMO BASÁLTICO DE AFINIDADE SHOSHONÍTICA EM AMBIENTE DE ARCO ARQUEANO, GRUPO GRÃO-PARÁ, SERRA DOS CARAJÁS - PARÁ

1991; Sociedade Brasileira de Geologia; Volume: 21; Issue: 1 Linguagem: Inglês

10.25249/0375-7536.19914150

ISSN

2177-4382

Autores

MARCELO R. MEIRELLES, MARCEL A. DARDENNE,

Tópico(s)

Geography and Environmental Studies

Resumo

BASALTIC VULCANISM OF SHOSHONITIC AFINITY IN ARCHEAN ARC ENVIRON-MENT, GRÃO-PARÁ GROUP, SERRA DOS CARAJÁS -PARÁ.The N4 and N8 orebodies in the Carajás district are associated to the Archean volcano-sedimentary Grão-Pará Group.The volcanic portion of this group comprises mainly basalts and basaltic andesites with local basic to intermediate pyroclastic intercalations.Associated intrusive bodies occur locally.Volcanic rocks were extruded in a subaqueous environment and submitted to hidrothermal metamorphic event of the greenschist facies.The absence of penetrative structures and the conspicuous occurrence of several primary textures are important features of the volcanic rocks associated to the orebodies.Geochemically the metabasic rocks are characterized by high contents of K, Ba and Rb, and low Zr, Nb and Ti, typical of the shoshonitic series.Petrologically the basic rocks of the Grão-Pará Group indicate a subduction zone geotectonic environment.

Referência(s)