THE THREE GENERATIONS OF GOLD IN THE PALAI-ISLICA EPITHERMAL DEPOSIT, SOUTHEASTERN SPAIN

• DOI: 10.2113/gscanmin.40.5.1465
• Publication Date: 2007-07-19T17:56:23Z
• Authors: F. J. Carrillo Rosua; S. Morales Ruano; P. Fenoll Hach-Ali
• Keywords: 01 natural sciences; 0105 earth and related environmental sciences

In the Palai‐Islica deposit, in southeastern Spain, gold is found associated with sulfide mineralization (particularly Fe sulfides). Grains of Au‐Ag alloy (gold types A and B) occur pyrite mineralized veins, grains native (type C) are areas massive silicification at uppermost levels deposit. The content “invisible” various sulfides practically nil. Of all textural varieties studied, unzoned medium- to coarse-grained only one bearing gold. clear distinction can be established between three (A, B C), each a different genesis. type-A deposited as result variations thermodynamic parameters system, mainly decrease sulfur activity, whereas appearance type-B was controlled by electrochemical factors. Type-C may have been produced from colloidal solutions significantly geochemical conditions. chemical evolution alloys characterized Ag enrichment precipitation continued. Type-A [mean Au/(Au + Ag) = 0.861] were first form, encased pyrite, relatively low barely any zonation, followed type B, overgrowing higher average [Au/(Au 0.756] commonly zoned, later zones richer Ag. Finally, type-C has no [on average, 0.988].