Polymetallic deposits within the Rachaite volcanic complex, province of Jujuy, Argentina : mineralogical and geological aspects / vorgelegt von Rodrigo Heidorn

• VerfasserIn: Heidorn, Rodrigo
• Place / Publishing House: 2002
• Year of Publication: 2002
• Language: English
• Classification: 38.10 - Geologie: Allgemeines
• Physical Description: 111 Bl.; Ill., graph. Darst.; 30 cm; Kt.-Beil. gef.
• Notes: Abweichender Titel laut Übersetzung der Verfasserin/des Verfassers

ger: In the back-arc of the Central Andes respectively Altiplano-Puna plateau NW-trending fault zones are associated with subparallel aligned volcanic zones and epithermal mineralisation. The intrusion-related epithermal and polymetallic Chocaya deposit, which is hosted by the calc-alkaline Rachaite Volcanic Complex (RVC), is structurally controlled by the NW-trending Lipez fault zone. This major discovery also implies that most other epithermal deposits throughout the back-arc of the Central Andes might be as well genetically linked to NW-trending fault zones. The Lipez fault zone in particular depicts a wrench corridor related directly to the convergence direction of the Nazca- and South America plates and to clockwise vertical axis rotation of intra-continental blocks in the Central Andes, which accounts also for the Calama-Olacapato-El Toro fault zone further south and maybe for all the other NW-trending major deformation zones in the Altiplano-Puna plateau. The Pb-Zn-Ag mineralisation of the Chocaya deposit is centred within the collapse caldera of the RVC and exposes approximately 6 km2 of phyllic- and propylitic alteration, silicification and steam- heated advanced argillic alteration and a younger pervasive supergene overprint. The mineralisation is confined to fault-controlled veins, veinlets and stockworks, which generated during deformation phase D1 by N-S shortening and right-lateral displacement of the Lipez fault zone as well as the Rachaite stratovolcano implantation. First volcanic activity occurred around 8.4 Ma with mineralisation initiating shortly after to 7.2 Ma maximum. Ore minerals, gangue, mineralisation textures and type of alterations lead to characteristics similar of the intermediate-sulphidation-state subset of the low sulphidation end member deposit style.