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 FERNANDO; 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. 394 - 406

0004-4822

The present study evaluates ASTER Image Processing asa technique to assist the lithological and mineralogical mapping of largegranitic bodies and associated hydrothermal alteration assemblages related tothe Cerro Áspero batholith, in Sierra de Comechingones, Argentina. Thisbatholith was formed by the successive emplacement of several sub circular,high-level crust plutons, that intruded, in the Upper Devonian, to metamorphicsequences of high to medium grade reworked by shear zones. Each of theseplutons developed internal, external and roof units, and dyke swarms. Internalunits are composed by porphyritic biotite monzogranites and external, roofunits 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.