Análisis metalogenético preliminar del depósito vetiforme en la mina La Ye, Antoquia, Colombia: características geológicas, isotópicas y estructurales

Edwin Naranjo-Sierra, Mauricio Alvaran-Echeverri, Eliselder Zapata-Cardona

Abstract


La Ye is a shear-zone hosted lode gold type deposit with brittle-ductile deformation which produced wallrock mylonitization, sigmoidal structures, boudinage and reactivation of vein-wallrock contact. At least four deformation events were identified, two of them are related to mineralization processes: Qz + Py ± Au for D2 sectors (dextral shear zones) and Qz + Py + Cp + Gn + Au-Ag tellurides + Pb tellurides + Au for D3 sectors (sinistral shear zones). Hydrothermal alterations and paragenetic association suggest that H2S o HS- ligand species were the predominant sulfur species in ore fluids and, in consequence, Au(HS)2- was likely the gold-transporting complex. Recrystallized quartz textures suggest low temperature (<350 °C) and brittle-ductile conditions. The δ18O values of hydrothermal muscovite associated to first mineralization stage and D2 event are +7.4 y +8.9‰, and the δD values are -49 y -50‰. The δ18O values of hydrothermal muscovite associated to second mineralization stage (and main event) and D3 event are +7.3 y +8.6‰, and the δ D values are -46 y -57‰. The δ34S values of pyrite associated to first mineralization stage and D2 event are +3.7 y +4.9‰ and δ34S values of pyrite associated to second mineralization stage (and main event) and D3 event are +3.95 y +5‰. These isotopic values are compatible with a magmatic and/or metamorphic origin for the ore fluids. These geological characteristics including structural controls, nature host-rock, hydrothermal alterations, mineralization style and isotopic composition of δ18O, δD and δ 34S suggest that La Ye deposit is compatible with the Orogenic Gold Deposits of Granitoid-Hosted Lode-gold Deposits subtype.


Keywords


orogenic gold; lode; shear zone; tellurides; stable isotopes; mina La Ye, Colombia



DOI: http://dx.doi.org/10.22201/cgeo.20072902e.2016.3.447

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