Lithological and mineralogical mapping of devonian Cerro Áspero batholith, Eastern Sierras Pampeanas, Argentina, using ASTER images

RADICE, STEFANÍA; PINOTTI, LUCIO PEDRO; MAFFINI, MARÍA NATALIA; CAMPANELLA, OSVALDO ROBERTO; DUCART, DIEGO; CONIGLIO, JORGE ENRIQUE; DEMARTIS, MANUEL; D'ERAMO, FERNANDO JAVIER

Revista de la Asociación Geológica Argentina

Asociación Geológica Argentina

Lugar: Buenos Aires; Año: 2017 vol. 74 p. 395 - 407

0004-4822

The present studyevaluates ASTER image processing as a technique to assist the lithological andmineralogical mapping of large granitic bodies and associated hydrothermalalteration assemblages related to the Cerro Áspero batholith, in Sierra de Comechingones,Argentina. This batholith was formed by the successive emplacement of severalsub circular, high-level crust plutons that intruded, in the Upper Devonian, tometamorphic sequences of high to medium grade reworked by shear zones. Each ofthese plutons developed internal, external and roof units, and dyke swarms.Internal units are composed by porphyri­tic biotite monzogranites and external,roof units and dyke swarms are dominated by two-mica and muscovite leucocraticmonzogranites to quarz-rich alkali-feldspar granites. The main associatedmineralizations are W-Mo magmatic-hydrothermal deposits and postbatholithepithemal fluorite deposits of cretaceous age. Supervised classification,principal component analy­ses and emissivity calculations were made to identifylithological composition and variations within the different plutons thatcomprise the Cerro Áspero batholith. This methodology allowed us to have abetter and precise mapping of the study area as well as the contacts betweenthe different plutons that comprise the Cerro Áspero batholith. Theclassification with spectral angle mapper methods allowed to identify thedifferent sectors with hydrothermal alteration (argillic and silicification).The argillic alteration is mainly associated with epithermal fluorite deposits.