Gold and silver mineralization in sulphide vein deposits of the Cikotok area, West Java, Indonesia

The Cikotok mineralization geologically and tectonically lies within the Tertiary volcano-magmatic belt of Java Island, and was affected by movement of the Tertiary, north-dipping Indian Oceanic plate which was subducted beneath the island arc. The gold-silver mineralization in the area is accompanied by base metal sulphides, and is hosted by a sequence of altered calc-alkaline volcanic rocks of the Oligo-Miocene Old Andesite Formation (comprising mostly andesites). The dominant forms of alteration to the host rocks include silicification, propylitization, carbonatization, sericitization, chloritization and argilitization.