Location:

Çeyeli-Madenkoy deposit. Turkey

Volcanogenic massive sulphides and associated stringer zones are found in the Eastern Black Sea metallogenic province of northeastern Turkey within submarine basic to intermediate volcanics of Cretaceous to Tertiary age. The deposits have been affected by the Alpine orogeny. The deposits have many features in common with Kuroko ores, notably they are stratabound within acidic lavas and pyroclastics. The massive ores are overlain by iron-rich cherts, or iron- and manganese-rich sediments and underlain by a stockwork (stringer) zone. The ores are fine-grained or brecciated and show primary bedding structures. The main sulphate gangue is baryte. The (Çeyeli deposit lies within pyroclastic units close to the top of the Dacitic Series and is overlain by purple tuffs and basalts. It comprises massive copper-zinc ores (black ore) and stockwork copper-pyrite ores. Quartz, baryte, calcite and clay minerals are the main gangue.

Major Minerals:

Chalcopyrite, pyrite, sphalerite, locally bornite

Minor Minerals:

Tetrahedrite group minerals, galena, marcasite, covelline

Trace Minerals:

Include native gold and numerous sulphosalts

Textures:

Fine-grained ore has extensive rhythmical precipitation of pyrite-bornite-chalcopyrite-silica. Coarse-grained ore also has extensive rhythmical precipitation of sphalerite-galena-chalcopyrite-tetrahedrite associated with baryte, or shows complex intergrowths of sphalerite-galena-tetrahedrite-chalcopyrite-bornite-pyrite. Pyrite is replaced along its cleavage by chalcopyrite, and sphalerite has chalcopyrite disease. Sphalerite encloses fine- to coarse-grained tetrahedrite inclusions

References:

Alton, 1978; Guy et al., 1983; Akinci, 1984