Mafic - Ultra Mafic Association and Related Mineral Deposits

• Grant number: 92/00649-9
• Support Opportunities: Research Projects - Thematic Grants
• Start date: November 01, 1992
• End date: May 31, 1997
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Vicente Antonio Vitorio Girardi
• Grantee: Vicente Antonio Vitorio Girardi
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant(s): 95/02461-5 - The Uruguayan mafic dike swarm (Southern South America) and correlative magmatic and sedimentary episodes in the evolution of Western Gondwanaland: a rift record of Mesoproterozoic age?, AR.EXT

Abstract

The aim of the project is to study the main types of mafic-ultramafic associations and associated mineralizations. The selected bodies occur in several regions of Brazil and in two areas in Argentina. Four types of mafic-ultramafic assemblages were selected: mafic dykes, mafic-ultramafic complexes, peridotitic nodules and metamorphosed mafic-ultramafic suites. Previous researches carried out by the staff in some of the bodies produced partial results. Otherwise, in several associations, the totality of the data must be obtained. Besides the knowledge of the petrology, geochemistry, geochronology, and metalogeny of the individual bodies, the research aims to contribute for the study of the geochemical evolution of the mantle, in the South American Platform, from the Archean to the Mesozoic. Investigations about mantle metassomatism, heterogeneity, and crustal contamination will be carried out. Another purpose of the project is to determine the geotectonic environments of the mafic-ultramafic assemblages and to analyse the crustal evolution of these areas. PGE, Au and Cr are the principal mineralizations related to the bodies. The aim is to investigate the formation and the concentration of the ores, and to elaborate possible metalogenetic models. (AU)