Geocronologia da região de Gondola-Nhamatanda (Centro de Moçambique) / não informado

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

17/01/2012

RESUMO

The region of Gondola-Nhamatanda is located at the border between the provinces of Manica and Sofala, central part of Moçambique. It is geologically inserted in the Bárue complex and the Phanerozoic cover. The Bárue complex is composed of the Macossa and Chimoio supracrustal groups intruded by plutonic rocks of various compositions, whereas the Phanerozoic cover consists of terrestrial sediments and volcanic rocks belonging to the Karoo Super-group and East African Rift Sequences. The work area was studied in terms of petrography; geochemistry of major elements, trace and rare earth elements; geochronology and isotope geology by the methods U -Pb in zircon, Rb-Sr and Sm-Nd in whole rock and Rb-Sr in minerals for the Inchope granite, Chissui mountain Quartzo-sienito and Xiluvo mountain phonolite. This study allowed to determine the lithotypes that intruded the Chimoio supracrustal group, its crystallization ages and the differentiation ages of the magmas that formed the protoliths and the tectonic framework. The studied rocks are basically calc-alkaline varying from meta to peraluminous for the granitoids and quartz-sienite and peralkaline for the mount Xiluvo phonolite. The Chimoio Group granitoids had been crystallized in the Mesoproterozoic (U-Pb and Rb-Sr ages) from Paleoproterozoic protoliths (\ T IND.DM\ = 1.7 - 2.4Ga); on the other hand, the volcanic rocks (phonolites) of the Xiluvo mount had crystallized fast in the Cambrian (Rb-Sr age) from a Neoproterozoic-Cambrian protolith (\ T IND.DM\ = 0.54 - 0.56Ga). The isotopic data, in the present study , suggest that the rocks of the Mozambique belt had been generated by partial melting that probably involved the mixture of the archean/paleoproterozoic crust and the Mesoproterozoic magma at 1100Ma and had suffered reworking marked by the Gondwana amalgamation (Pan-African orogeny) and extensional processes marked by the Gondwana break up (East African Rift).

ASSUNTO(S)

cristalização crystallization extensional process geochronology geocronologia idade isocrônica idade modelo isochron age model age orogênese orogenesis tafrogênese

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