Author(s): BERGMANN, M.; HOFF, R.; DUCATI, J. R.

Summary: Establisment of a rocks and soils spectral library is proposed for CPRM-Brazilian Geological Survey, for improvement of rocks and soils spectral signature obtainance as a help for field data and satellite images correlation for geological mapping purposes. Spectrometric measures will be runned on grinded rocks by means of a Portable Spectrometer for Analytical Mineral Identification (POSAM), witch operates in the infrared spectra band at CPRM?s Remote Sensing and Spectroradiometry Lab. Hydrothermal alteration studies employng spectroradiometry and ASTER data DIP have been done for shiel rocks on southern Brazil, and are presented for 3 areas. At Lavras do Sul Minig District, gold and cooper prospects hosted in neoproterozoic volcanics and post tectonic granithoids had deposits and host rocks identified, plus hydrothermal alteration assemblages as white mica, montmorillonite, kaolinita. epidote, zeolite, calcite and jarosite. Vila Palma?s gold cooper and molibdenium propects, hosted by metamorphic mafic volcano-sedimentary sequence neoprotherozoic in age, showed as early results hidrothermal alteration assemblages like kaolinite,chlorite, muscovite, calcite and zeolite group minerals on sulphide bearing quarts veins, besides anphibole and chlorite on host rocks and zeolite+chlorite or chlorite+calcite+zeolite on the ores. At Pinheiro Machado, neoprotherozoic granite-gnaissic complexe and intrusive granitic assemblage followed by gabbroid rocks has been investigated for establishment of vine terroir. Alteration mineral assemblages like montmorilinite, sericite, clorite, natrolite; laumontite, calcite and epidote seem to discriminate distinct litostratigraphic units. Concluding, the establishment of a spectral library on CPRM will improve the data bank of Brazilian Geologic Survey, already in GIS environment, helping geological mapping and prospective activities.

Publication year: 2009

Types of publication: Paper in annals and proceedings

Unit: Embrapa Grape & Wine

Keywords: ASTER, Biblioteca espectral, Companhia de Pesquisa de Recursos Minerais, Espectrorradiometria, Geologia, Memória, Rio Grande do Sul