Listwaenites in Turkey: Perspectives on formation and precious metal concentration with reference to occurrences in East-Central Anatolia

The low hydrothermal alteration of serpentinites from the ophiolite complex es in Turkey has formed listwaenites with either mineralized or non-mineral ized and scattered through the three-ophiolite belts in Anatolia, Turkey. T he listwaenite occurrences and associated mineralization in Turkey are revi ewed, taking into account the location and description used in literature. The geology and geochemistry of the listwaenites in east central Anatolia s erve as a reference to illustrate the characteristics of listwaenite format ion and precious metal concentrations in ophiolite belts of Turkey. The late Cretaceous (Pre-Maastrichtian) alteration of serpentinite bodies i n the Divrigi and Kuluncak ophiolitic melanges, in east central Anatolia ha s formed two distinct types of listwaenite. The earliest is silica-carbonat e listwaenite (type I), which is dominated by silica+calcite+dolomite+anker ite+/-magne site. Later, carbonate listwaenite (type II) comprise calcite+d olomite+ankerite+/-magnesite, and lack any significant introduction of sili ca. In the Divrigi and Kuluncak ophiolitic melanges the most of the silica-carb onate (type I) and carbonate (type II) listwaenite are formed along thrust fault zones. In clearly fault-related listwaenites thrust fault(s) acted as pathway for hydrothermal fluids. In non fault-related listwaenites, hydrot hermal fluids moved along highly serpentinized microfractured, stockworked and porous ultramafic rocks. The hydrothermal fluids involved in the format ion of carbonate (type LT) listwaenite differed from those that formed sili ca-carbonate (type I) listwaenite, which was enriched in SiO2, as well as C O2, Ca and H2O, whereas those that formed carbonate listwaenite were SiO2 d eficient, and enriched only in CO2, Ca and H2O.