ii
SARI
Daerah penelitian terletak pada cebakan emas Cibaliung, Kecamatan Cibaliung, Kabupaten Pandeglang, Provinsi Banten. Daerah Rorahkadal secara geologi terletak pada komplek batuan beku Honje dan disusun oleh batuan beku vulkanik Miosen yang mengalami alterasi dan mineralisasi. Penelitian mencakup studi alterasi dan mineralisasi dengan metode penelitian yang dilakukan yaitu analisis petrografi, analisis mineragrafi dan analisis inklusi fluida.
Tipe alterasi yang terbentuk di daerah Rorahkadal ada dua yaitu tipe propilitik dan tipe silisifikasi dengan kumpulan mineral-mineral ubahan yang ada di daerah Rorahkadal yaitu silika, klorit, mineral lempung, epidot, kalsedon dan oksida besi.
Pembentukan mineralisasi di daerah Rorahkadal yaitu pirit, kalkopirit dan sfalerit. Mineral bijih tersebut hadir berupa urat sulfida (stockworks), tersebar (disseminated) dalam masadasar batuan, serta hadir pada permukaan batuan. Asosiasi mineral-mineral bijih tersebut dapat mengindikasikan adanya pengkayaan Au di daerah Rorahkadal. Mineralisasi di daerah Rorahkadal dipengaruhi oleh kekar yang secara regional berarah utara selatan.
Berdasarkan pengukuran inklusi fluida diketahui bahwa temperatur homogenisasi (Th) berkisar antara antara 120~229 °C dengan rata-rata Th=191.5 °C, temperatur leleh (Tm) berkisar antara 0,18~0,94 °C dengan ratarata Tm= -0,65 °C dan salinitas fluida hidrotermal berkisar antara 0,32~1,67 wt% NaCl eq. dengan rata-rata salinitas = 1,53 wt% NaCl equivalen.
iii
ABSTRACT
Study area is located at Cibaliung gold deposit that administratively is a part of District Cibaliung, Pandeglang Sub Province, Banten Province. Geologically this area belongs to Honje igneous rocks complex in which dominated by Miocene volcanic igneous rocks that already have been alterated and mineralized. Objective of the research is studying alteration and mineralization process by using some methods, such as Petrography analysis, Mineragraphy analysis and Fluid Inclusion analysis.
The study area composed by prophylithic alteration and silicification alteration. Associated alteration minerals such as silica, chlorite, clay minerals, iron oxide, epidot and chalcedony.
Mineralization process at Rorahkadal, such as : sulphide group (pyrite, chalcopyrite and sphalerite). The ore minerals was formed as stockworks, disseminated minerals within groundmass of rock and coating minerals on the surface of the rocks. The ore minerals associated can showing indicated that Au and other precious metal enrichment in Rorahkadal Area. Mineralization at Rorahkadal area controlled by activities of sheer that regionally trending North-South.
Based on fluid inclusion measurement, the temperature homogenization is in range 120~229 °C with Th average is191.5 °C, temperature melting (Tm) is in range -0,18~-0,94 °C with Tm average is -0,65 °C and salinity of fluid hydrothermal is in range 0,32~1,67 wt% NaCl equivalent, with average salinity is about = 1,53 wt% NaCl equivalent.
