Pustaka Ilmiah Universitas Padjadjaran

Abstrak

Ore Mineralogy of Cijulang High Sulfidation, West Java, Indonesia

The Cijulang High Sulfidation mineralization area is located in the vicinity of Garut Regency, West Java Province. This study will describe the ore mineralogy that could be related with possibility of porphyry type mineralization underneath. Several samples were collected from five drill holes. The ore mineralogy is identified by ore microscopy and ore compositions were measured using SEM-EDAX. The lithology of the Cijulang area is covered mainly by pyroclastic rock volcanic product of Pleistocene age and microdiorite intrusion of Late Miocene age. Structural analysis observed that the distribution of alteration and mineralization within the Cijulang prospect is controlled by lithology and fault NS and NE-SW trends. The alteration is indicated by the occurrences of vuggy silica, pyrophylite, dickite, kaolinite, illite and smectite-chlorite that classified into four major zonation of prophylitic, argillic, advanced argillic and massive quartz respectively. The mineralization of Cijulang prospect is characterized by massive silica-vuggy quartz texture distributed at Cisuru, Limus and Dangur parallel along the Cikahuripan River. Ore mineral assemblage is mainly composed of pyrite, enargite, tetrahedrite, tennantite, in associated with minor chalcopyrite, galena, stannite, anatase and bismuthinite rarely horobetsuite, gaLkaite, guanajuatite, arsenopyrite, and stannoidite, include some very tiny unknown minerals contain Mo. Most rare ore minerals are occurred as inclusion in enargite, tenanntite or sometimes pyrite. This ore minerals assemblage is very different with other mineralization prospect within the region. Some drill holes data indicate the occurrence of porphyry dioritic host rock that contain veinlets which composed of quartz, chalcopyrite, pyrite, magnetite and sometimes tourmaline. The present of ore minerals that contain Bi and Mo elements gives indication to the possibility of the occurrences of porphyry system underneath. Therefore, present exploration target is focused to drill deeper part in order to get more understanding of the mineralization system.