Determination of geophysical and geochemical parameters for the elaboration of evolution models of the lithospheric segment of S-SE of Brazil

• Grant number: 90/03741-8
• Support Opportunities: Research Projects - Thematic Grants
• Duration: August 01, 1991 - July 30, 1994
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal Investigator: Marta Silvia Maria Mantovani
• Grantee: Marta Silvia Maria Mantovani
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The study of the earth's lithosphere, in this last decade, has received special attention on the part of the international scientific community. There are various committees and sub-committees affiliated to the "Inter-Union Commission on the Lithosphere" which aim to integrate information from the participating countries to coordinate the study of the lithosphere on a global level. Among the various disciplines which participate in this integrated study, Geophysics enables it to determine its physical parameters, inferring its structure through models which are linked by these parameters. Geochemistry provides its composition and, from this, infers the possible magmatic processes which occurred for its formation. Knowledge of the lithosphere as to its composition, to its structural characteristics and the dynamic involved is, however, vital for tracing its evolutive history. The area where GEOLIT has focused its main interest occupies part of the South American platform, consolidated during the Brazilian cycle (Upper Proterozoic - Lower Paleozoic). The Paleozoic - Mesozoic evolution of this area was marked by the development of the vast and intracratonic basin of the Paraná, which during the lower cretaceous was the scene of one of the most spectacular episodes of continental magmatism. Its evolution was strongly controlled by the tectonic nature of the proterozoic-Cambrian structures of its foundations The volcanic eruptions, which formed the largest province of continental basalts in the globe, are the natural record of the composition of the underlying mantle of the same, and of the magmatic processes which preceded the rupture of the Gondwana in its southern portion. The study of the geophysical and geochemical characteristics of the Paraná basin and the lands that surround it is, therefore, vital to the understanding of the evolutive history of this lithospheric segment. The primary objective of the project is the study of the S-SE lithospheric segment of Brazil and of its evolution in geological time, for the realization of which: a) data will be collected on the geophysical and geochemical, isotopical properties and on the physical properties of the rocks; b) existing geological and geophysical data on the area will be gathered; c) numerical techniques will be used for the reduction, interpretation of the data acquired and for the elaboration of the geophysical models which will be used to describe the results of the research; d) new methodologies will be implemented to provide a greater number of links in the interpretation of the data; e) the training of personnel in this area of knowledge through the participation of undergraduate and graduate students will be promoted. Within the present project, the goals to be achieved are: gravimetric densification; elaboration of the aeromagnetic database; evaluation of the deep seismics and of the Seismology of surface waves for the study of the lithosphere in the region of interest; comparative analysis of the tidal response; Geochemical compartmentation; integration and interpretation of the data. (AU)