Crustal evolution of South America

• Grant number: 95/04652-2
• Support Opportunities: Research Projects - Thematic Grants
• Start date: August 01, 1996
• End date: August 31, 2000
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Umberto Giuseppe Cordani
• Grantee: Umberto Giuseppe Cordani
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant(s): 99/05430-4 - Masaru Yoshida | Osaka City University - Japão, AV.EXT; 98/13426-4 - Louise Frick | Monash University - Austrália, AV.EXT; 98/06964-0 - Isotopic constrains on the proterozoic geological history of the amazonian craton., AR.EXT; + associated grants 98/06858-5 - Nd-sr characteristics bearing onarchean magmatic episodes of the subcontinental mntle, campo belo complex, sao francisco craton, brazil., AR.EXT; 98/06882-3 - New trends in geochronological interpretation., AR.EXT; 98/03151-8 - Costas Xenophontos | Geological Survey Departament - Chipre, AV.EXT; 98/00404-2 - José Manuel Urbano Munha | University of Lisbon - Portugal, AV.EXT; 97/05483-5 - Sr, nd and pb isotopic signature on granitoid intrusives of the paleoproterozoic mineiro magmatic arc, southern sao francisco craton., AR.BR; 97/03159-6 - U-pb(shrimp),sm-nd and re-os systematics of the cana brava, niquelandia and barro alto layered intrusions in central brazil, and constrians on the tectonic evolution., AR.BR - associated grants

Abstract

The level of geological knowledge in the South American continent has grown in a continuous process since the first syntheses which date back to the end of the 60s decade. As new items of information were being incorporated into the body of existing data, this knowledge brought about modifications in the South American geotectonic picture. As the main geo-chronological Laboratory operating in South America, the Center for Geo-chronological Research of the Institute for Geosciences in the University of São Paulo (CPGeo) has greatly contributed to the recognition of the principal ages of metamorphism and magmatism which occurred in the continent. This project aims to refine the current tectonic picture and of the crustal evolution of the continent, with an isotopic detailing of key areas using, over the next three years, isotopic methodologies of greater interpretive power than the CPGeo is in a position to offer and also more advanced techniques still not available in the country, such as U-Pb through SHRIMP, which the CPGeo, is in the process of obtaining through a cooperation agreement with the National University of Australia. The qualitative leap sought will be attained thanks to the capability now available of obtaining, systematically, ages of U-Pbin zircons, Sm-Nd in total rock and minerals and Pb-Pb in total rock and feldspars, methods such as these of great interpretative (geo-chronological and petrogenetic) potential. The proposing team will study several key areas scattered across the South American Platform and the Andean Belt where the new methodologies will be applied, in well known geological problems. Through analysis of these results it is hoped to obtain concrete information on the following points: (a) characterization of the principal ages of continental growth with definition of the accretion explanation versus the crustal reworking; (b) temporal characterization of the main orogenetic events in the South American Platform with definition of the age of installation (sedimentation) of the principal belts of folds; geo-chronological characterization of the reflex on the South American Platform of the main Andean orogenic pulses. (AU)