Análisis de texturas epitermales en depósitos de fluorita de las Sierras Pampeanas Orientales: su aplicación como criterio de prospección

JORGE CONIGLIO, FERNANDO DERAMO, LUCIO PINOTTI, MANUEL DEMARTIS4, LEONARDO AGULLEIRO INSUA5 Y HUGO PETRELLI6

CATAMARCA

Congreso; IX CONGRESO ARGENTINO DE GEOLOGÍA ECONÓMICA; 2009

Asociación Argentina de Geólogos Economistas

ABSTRACT. Epitermal textures analysis in  uorite deposits in Sierras Pampeanas Orientales: its application asprospecting criteria. The main Mesozoic epithermal  uorite veins of southern Sierras Pampeanas occur in porphyriticbiotite monzogranites belonging to Upper Devonian plutons. The  uorite veins occupy steeply dipping, strike-slipregional fault zones and are composed of  uorite and chalcedony. These veins were generated by multiple stagesof opening and sealing. Eleven successive generations of  uorite deposition were identi ed on the basis of veinchronology, textural relationships and mineralogical data. In this context, several epithermal textures and veinmorphologies were developed depend on former mechanism of the open space in country rocks.Fluorite texturesevolve in the  lling history of the veins from massive, to thin-banded, colloform and eventually late replacementtextures. Proved ore of 300.000 t with 40 to 60% CaF2 were calculated within tabular veins. Discontinuous, alignedbiconvex lenses were recognized in compressive dominant fault systems. Breccia and sacaroid textures dominatein these veins, where 1.000 t (proved ore) with <45% CaF2 are exceptionally found. The fact that some of the uorite generations are absent in several veins in the investigated areas, con rm that the mineralized structureshad different times of opening and sealing, and thus the depositional sequence established could be used as aneffective prospection criteria.