Pustaka Ilmiah Universitas Padjadjaran

Abstrak

Zona Alterasi Berdasarkan Data Bor Daerah Arinem, Kecamatan Pakenjeng, Kabupaten Garut, Provinsi Jawa Barat

Daerah penelitian terletak di Arinem, yang termasuk wilayah tambang PT ANTAM, Tbk. Daerah Arinem ini tersusun oleh satuan andesit (Tpa), satuan tuf (Qtv), dan satuan breksi tuf (Tpbt). Menurut hasil pengamatan petrografi dan pengamatan XRD (X-Ray Diffraction) didapatkan kehadiran mineral ubahan dengan mengacu pada klasifikasi Leach (dalam Corbett dan Leach, 1996), maka zona ubahan dapat dibagi menjadi tiga zona alterasi, yaitu : zona klorit, zona kaolin-ilit, dan zona silisifikasi. Berdasarkan analisis mineragrafi ditemukan mineral bijih berupa pirit, kalkopirit, dan galena. Mineral-mineral tersebut terbentuk secara menyebar (disseminated) dan penggantiann (replacement). Berdasarkan jenis alterasi dan mineral bijih yang ditemukan maka alterasi daerah Arinem ini termasuk ke dalam tipe alterasi epitermal sulfidasi menengah (epithermal intermediate sulfidation).

Arinem is located in Gold Exploration Arinem PT Antam Tbk. Arinem area is composed of andesite unit (Tpa), tuff unit (Qtv), and tuff breccia unit (Tpbt). According to the results of petrographic observations and the observations of XRD (X-Ray Diffraction) found the presence of alteration minerals with reference to the classification Leach (in Corbett and Leach, 1996), the alteration zone can be divided into three alteration zones, namely: chlorite zone, kaolin-illite zone , and silicified zones. Based on the analysis of mineral ores found mineragraphy form pyrite, chalcopyrite, and galena. These minerals formed by spreading (disseminated) and replacement. Based on the type of alteration and ore minerals are found then the alteration Arinem area is included in the intermediate sulfidation epithermal alteration type.