Espectroscopía de reflectancia aplicada al estudio de depósitos polimetálicos de Pb, Zn, Cu ± Ag ± Au del sur de la Sierras de Córdoba, Argentina

MAFFINI, MARÍA NATALIA; DUCART, DIEGO FERNANDO; CONIGLIO, JORGE ENRIQUE; D'ERAMO, FERNANDO JAVIER; MOREIRA SILVA, ADALENE; DEMARTIS, MANUEL; TOLEDO, CATARINA LABOURÉ BEMFICA; PINOTTI, LUCIO PEDRO

Joao Pessoa

Simposio; XVII Simpósio Brasileiro de Sensoriamento Remoto (SBSR); 2015

Instituto Nacional de Pesquisas Espaciais - Ministério da Ciência e Tecnologia

This paper describes the application of spectral andmagnetic analysis techniques in hydrothermal alteration zones related topolymetallic deposits, in the Sierras de Córdoba (Argentina). The sampling for spectralanalysis was carried out in two key study areas and it involved severalmineralized structures. The mineralization occurs as discordant tabular veins,mainly composed of quartz with variab le contents of sulfides and Au-Agminerals. Hydrothermal alteration of the metamorphic host rocks is conspicuous,being the phyllic alteration the most distributed along the structures. Thespectral analysis results revealed notable differences between the altered hostrocks and their non-altered protholiths. In the alteration zones there is anincrease in the abundance of white micas and its crystallinity, however, at thesame time the rocks show lower magnetic susceptibility values. One of the mostoustanding result is the variation in the composition of illite in somemineralized structures, from normal potassic to phengitic. The spatialdistribution of phengitic illite is genetically related with thephysicochemical characteristics of the hydrothermal fluids, in the study areasits occurrence is restricted to the most mineralized metallotects. Theapplication of spectral analysis in polymetallic veins has not been mentionedin the Sierras Pampeanas. However, this study reveals considerable advantagesof the method, allowing the rapid identification of hydrothermal mineralassociations, variations of parameters of composition and abundance anddifferenciation of several types of fine grain minerals. Therefore the spectraland magnetical data can have considerable importance for the characterizationof hydrothermal alteration zones in this type of mineral deposits.