Discovery of Au–Ag mineralization by stream sediment and soil geochemical exploration in metamorphic terrain in western Turkey

Abstract

Exploration based on BLEG (bulk leach extractable gold) and −80mesh stream sediment, and soil geochemical sampling over the Usak-Esme region in western Turkey resulted in the discovery of Cemalcavus Au–Ag–As mineralization. This schistosity-controlled mineralization occurs within sericitized–chloritized almandine–amphibolite facies metamorphic rocks. No mineralization has been reported previously in the area. The concentration–area (C–A) fractal model was applied to the raw data to set threshold values defining background and anomalous classes of uni-element concentrations in BLEG and −80mesh stream sediment samples as well as soil samples analyzed by conventional and MMI (mobile metal ion) extraction techniques. The conventional soil geochemical data failed to yield anomalies linked to gold mineralization at or close to the surface whereas the MMI soil geochemical data yielded genuine anomalies that were not only reproducible but were associated with subsurface mineralization. Thus, the MMI technique has maximized drilling efficiency at Cemalcavus Prospect by providing precise anomalies closely related to subsurface sources. As a whole, BLEG and −80mesh stream sediment anomalies in combination with MMI soil anomalies followed-up by core drilling led to the recognition of the Cemalcavus Au–Ag prospect although an economically viable mineralization is yet to be discovered.