GEOLOGI BATUAN BEKU BASA - ULTRABASA DAERAH BULI DAN SEKITARNYA, HALMAHERA TIMUR MALUKU UTARA, DALAM HUBUNGANNYA DENGAN ENDAPAN NIKEL LATERIT

• Main Author: Raswan D , Erwin
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/7833
• Institution: Institut Teknologi Bandung

Abstract: <br /> Buli is the Contract of Work (CoW) area of PT. Aneka Tambang (Antam) Tbk, administrativelly the area lies on Maba and South Maba districts, East Harmahera, North Maluku Province. Based on exploration of nikel laterite deposit in Buli area , the prospect areas can be divided into 4 prospect blocks : Tanjung Buli, Monoropo, Sangaji and Pakal Blocks. Lithologic rocks of Buli area are composed ultrabasic, basic , limestone and aluvial rocks unit. Lithologic of basic-ultrabasic rocks cover about 85 of research area and consists of dunite, harzburgite, pyroxenite, serpentinite, gabbro and diabase. Almost of this rocks were serpenitized with different intensity, based from petrographic analysis show ; serpentinite has strong intensity of serpentisation (aproximately 50-88), moderate to strong intensity of dunite (between 5-7) and harzburgit (2-40), weak to moderate on piroxenite (5-7) and gabbro (3-10), very weak on diabase (0). The presence of serpentine mineral is very important to control Ni content of serpentinized rocks. Result of mineragraphy analysis from 12 samples of basic-ultrabasic rocks shows the presence ore minerals of pentlandite and heazelwoodite, garnerite and limonit as fracture filling minerals of serpentinized rocks. Pentlandite is primary ore mineral which is producted by magmatisme, while heazelwoodite, limonite and garnierite are secondary minerals that is formed by weathering activity. The presence of heazelwoodite can increasing Ni grade on serpentinized rocks. <br />