Hubungan Morfologi dengan Karakteristik Laterisasi pada Endapan Nikel Laterit Daerah AXZ, Kota Maba, Halmahera Timur, Maluku Utara

Abstract

Nickel is one of the natural resources that has many benefits for various other types of products, this versatility is also what makes nickel very valuable and has a high selling value in the world market, The existence of laterite nickel deposits is generally widely spread in the eastern region of Indonesia, including in East Halmahera, Central Halmahera, in addition to the South Sulawesi region,  Central Sulawesi, and Southeast Sulawesi. This research was conducted at PT. Antam Tbk, located in East Halmahera, North Maluku, aims to determine the morphological relationship with the characteristics of laterization of laterite nickel deposits. The research methodology was carried out by literature study, field mapping, geomorphological analysis, lithological analysis, laterite thickness analysis, and analysis of Ni, Co, Fe2O3, SiO2, MgO, and Al2O3 levels. The geomorphology of the study area is divided into steep hill geomorphology units, steep hill geomorphology units, and sloping plain geomorphology units, with lherzolite units and dunits that fill the geological units of the study area which are ultra-alkaline rock formations. The geological structure of the research area is fractured with a relative orientation of northwest – southeast and then northeast – southwest. The laterite deposits in the study area consist of top soil, limonite, saprolite, and host rock zones that are included in  the hydrosilicate deposit type, with the thickness of the saprolite zone higher than the limonite zone and top soil. The morphological relationship to the distribution of laterite nickel can be seen in the steeper the slope, the thicker the saprolite zone compared to the steeper slope and the steeper the slope, the thinner the laterite deposit, where  the Ni element experiences enrichment in the saprolite zone and then the element Co experiences enrichment in the limonite zone while the Fe element experiences enrichment in the top soil zone. Laterization and weathering processes are most developed on steep slopes and thicker laterite deposits. The results of this study are expected to be a reference in exploration and evaluation activities of laterite nickel deposits in similar areas.