Fluid inclusion geochemistry in minerals obtained from Zhao-Ye gold metallogenetic belt, Shandong Province

Abstract

A large number of fluid inclusions are observed in quartz contained in Au ores. A study of the geochemistry of inclusions from the Linglong Au deposit in Shandong Province shows that ore-forming temperature and pressure, frequency of appearance for critical inclusion, and saline halo of the main Au-bearing veins 108 and 51 increase in the direction of Linglong Fault. We concluded accordingly, that: (1) the Linglong Fault was a conduit structure for mineralization and will form a favourable place for prospecting where the fault intersects a host structure trending east-northeast; (2) distinct differences in geochemical characteristics are present in relation to the fluid inclusions contained in Au-bearing quartz veins and barren quartz veins, with the former having higher homogenization temperatures, appearing frequency for critical inclusion, content of CO 2, H 2 and CH 4, and molar concentration ratio of (H 2 + CH 4) to CO 2, than those of the latter; (3) decrepitation curves for the two sorts of quartz veins have obviously different characteristics; and (4) geochemical characteristics of fluid inclusions present in the quartz of quartz-vein-type Au ore deposits demonstrate that its metallogenetic pressure, salinity, and decrepitation temperature all increased progressively towards the deeper part of the quartz vein, approximating those of altered-rock-type Au ore deposits. We already know of some Au mines where quartz-vein-type Au ore deposits are turned at depth into altered-rock-type Au ore deposits. Therefore, attention should be paid to prospecting for altered-rock-type Au ore deposits below the quartz-vein-type. From this study, we believe that the geochemical study of fluid inclusions in minerals is a new and useful exploration approach, which should be further explored and used.