Stream Sediment Geochemical Exploration for Gold in the Kazdağ Dome in the Biga Peninsula, Western Turkey

Authors: HÜSEYİN YILMAZ

Abstract: The Tuztaşı Au-Ag mineralized system was discovered within the Kazdağ dome using BLEG (bulk leach extractable gold) and 180-µm stream sediment geochemical data collected across the Biga Peninsula in western Turkey. The deposit is located within the hinge of an antiform consisting mainly of high-grade metamorphic and mélange rocks that include the Altınoluk Pb-Zn-Cu-Ag-Au and Evciler Fe-Au-Cu deposits on the southern and on the northern flanks, respectively; no mineralization has been reported prior to this work which was first carried out in 1996 between Altınoluk and Evciler. The BLEG Ag/Au ratios at Tuztaşı (max 87) and Altınoluk (max 43) are very high to extremely high demonstrating the area to be relatively Ag-rich. This Ag enrichment is further demonstrated by rock chip Ag/Au ratios reaching up to 43 at the Tuztaşı deposit. Silver is a moderate to very effective pathfinder for Au at Tuztaşı. Arsenic is useful, being more mobile than Sb. Arsenic also constitutes the most coherent and the most significant geochemical anomaly in the northern half of the AYALE (Ayvacık-Altınova-Evciler) area which is underlain mainly by the mélange rocks intruded by granitoid. The BLEG sampling accompanied by further follow-up 180-µm stream-sediment sampling is a powerful technique in detecting Au-Ag deposits or occurrences. BLEG appears to be a time- and cost-efficient stream sediment geochemical technique for discovering relatively large primary geochemical halos encompassing the precious (Au, Ag) and base metal (Cu, Pb, Zn) deposits.

Keywords: BLEG sampling, geochemistry, gold, mineral exploration, Kazdağ, western Turkey

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