Inclusiones fluidas en material filoniano del Valle de Ribes, Pirineos Orientales, España

Abstract

Fluid inclusions in quartz and scheelite from two localities of a vein field have been studied. The veins are related to a latehercynian granitic intrusion. The ore minerals from the veins are arsenopyrite, pyrite, pyrrhotite, chalcopyrite, gold and sulphosalts of the PbS-Bi z-S,-Sb2S 3 system. Two kinds of fluid inclusions have been found in both localities: a biphasic type and a CO2 rich triphasic type. Homogeneization temperatures of the first type inclusions are around +150 °C in the locality nearer to the intrusion, and around +200 °C in the other one. Therefore, zonation of the temperatures with regard to the granitic outcrop is inverted. Studies in the chemistry of the mineralizing solutions have been also carried out. The homogeneity in the type of inclusions can be followed in both localities, by means of similar salinities, and it is around 17 % weight NaCI for biphasic inclusions. In these inclusions the presence of CaC12 in the solutions is showed by a drecrease of euthectic temperatures from the theoretical —21 °C in the pure NaCI-H20 system. The amount of Ca02 is variable, but higher in inclusions found in the scheelite compared to coexisting quartz. The CO2 liquid density is also very variable even in adjacent inclusions from the same specimen, but is comparatively higher in veins from localities far away from the intrusion, where the wall rock is calcareous.