Gold-bearing listwaenites in the Arac Massif, Kastamonu, Turkey

The mineralogy and chemistry of gold-bearing listwaenites of Gemikoy in the Arac gmassif (southern part of the Daday-Devrekani massif) were investigated in detail. The process of listwaenitization and the reasons for gold enrichment in the area are discussed. The listwaenites have no direct contact with any magmatic intrusion or extrusion. Detailed chemical analysis showed that the listwaenitized rocks contain silica-, silica and carbonate-, and carbonate-rich parts. Each part is different chemically from the others, even in terms of accessory mineral content. In general, the listwaenites differed chemically and mineralogically from the surrounding ultramafic rocks. In particular, SiO2 and CaO contents of listwaenites were higher and MgO and Al2O3 contents were lower than in the surrounding ultramafic rocks, Furthermore, Ni, As, Mn, Zn, Pb and Co enrichment occurred during listwaenitization, while K was absent and Ni enrichment was detected especially in silica and carbonate-, and carbonate-rich parts. Finally, Gemikoy listwaenites are interpreted as autometamorphic, even though they show similarities to allometamorphic listwaenites accorcling to Ploshko's (1963) classification.