The Au-Cu epithermal deposit at Palai-Islica, Almería, SE of Spain: Preliminary data

Abstract

The following sequence of hydrothermal alteration has been indentified within the epithermal gold/copper-bearing deposit at Palai-Islica: propylitic, sericitic, argillitic (extending over a surface area of some 2.5 x 1.7 km2), and silicic (± carbontation). Mineralization appears in association with quartz viens, stockworks and layers of silica with sulphides (pyrite±chalcopyrite±other minor sulphides and native gold). Three fluids have been identified related to the mineralization: (A) a high-temperature, high-salinity fluid (magmatic=); (B)a fluid of relatively constant tremparature and varible salinity; and (C) a lower temperature and relatively low, constant salinity fluid (ground waters?). The considerable difference in the nature of these fluds (due mainly to the isothermal mixing of A and B fluids and a heterogeneous entrapment of the solutions- due possibly to boiling-) seems to have been responsible for the precipitation of gold.