KARAKTERISTIK ANOMALI, PERSEBARAN UNSUR, DAN ASOSIASI UNSUR DAERAH KOTA TIDORE KEPULAUAN, PROVINSI MALUKU UTARA

• Main Author: Supriyanti, Nisa
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/40535
• Institution: Institut Teknologi Bandung

Kota Tidore Kepulauan is a part of western Halmahera Island, North Maluku. Halmahera is located in the centre of triple major boundary complexity between Australian Plate, Eurasian Plate, and Phillipine Sea Plate. This complexe Halmahera geological evolution causes mineral resources potential of eastern Indonesia interesting to be examined as an early stage of mineral exploration from geochemistry perspective. Lack of geology research in Halmahera encourages this study to be accompolished to support previous and future related researches. 25 geochemical element datasets from 100 stream sediment samples processed by AAS and ICP MS method are interpreted using statistical approach in order to identify anomaly, element distribution, element associations, elemental/mineral prospecting, and related geological history. This study utilizes two statistical methods including univariate analysis and multivariate analysis. Univariate analysis is applied to determine anomalies or threshold values of each elements. Three methodologies of multivariate analysis including Pearson coefficient correlation method, percentile method, and cluster analysis method are applied to determine element associations. Petrography and mineragraphy analysis from 7 rock samples and grain counting analysis from 20 pan-concentrate samples are used to substantiate geological history interpretation. The result of threshold value from each elements processed by univariate analysis is compared to the referenced element concentration data based on literature. All elements generally possess higher concentration compared to the literature reference except for these following elements; nickel, chromium, alkaline elements, and earth alkaline elements. Anomalies are equally distributed in all formations particularly in Bacan Formation and Weda Formation. Multivariate analysis results five association propensity groups as follows; Zn-Fe-Cr-Co-(Ni)-(Mn), Cu-Pb-Au-Ag, Ce-Yb-Sm-Pr-Gd-(Bi), Li-K-Rb-Ba-(Na)-(La)-(Sr), and Sc-Nd. Grain counting analysis carries iron oxide mineral abundance, especially magnetite (Fe3O4). Petrography and mineragraphy analysis indicates that Alluvium and Coastal Deposit Unit consists of silicified basalt fragment and silicified tuff fragment, Weda Formation consists of limestone and pyrite, and Bacan Formation consist of silicified tuff, magnetite, chalcopyrite, and pyrite. The potential of mineralization indication including iron supergene enrichment and epithermal/porphyry occures in these following areas; Timur Maramake, Gitaislam, A. Tarawi, and Bk. Lenggua and Bk. Kuluting.