STUDI POTENSI THORIUM PADA BATUAN GRANIT DI PULAU BANGKA

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ABSTRAK

STUDI POTENSI THORIUM PADA BATUAN GRANIT DI PULAU BANGKA. Di Indonesia umumnya thorium dijumpai dalam batuan granit. Salahsatunya di pulau Bangka, terdapat cukup banyak singkapan batuan granit, seperti granit Menumbing, granit Pelangas, granit Jebus, granit Pemali, granit Mangol, granit Bebuluh dan granit Gadung. Penyebaran granit-granit tersebut cukup luas sehingga dianggap sebagai granit potensial thorium. Tujuan penelitian untuk mengetahui potensi thorium pada batuan granit yang terdapat di pulau Bangka. Metode yang digunakan adalah pengambilan sampel mineral berat dari batuan granit lapuk, selanjutnya dilakukan pengukuran dan analisis thorium di laboratorium menggunakan X-Ray Fluorescence. Batuan granit dianggap potensial thorium apabila mempunyai kadar thorium minimal tiga kali kadar thorium dalam granit normal (15 ppm) dan batuan granit telah mengalami pelapukan tingkat lanjut sehingga mudah untuk ditambang. Hasil studi menunjukkan bahwa kadar thorium pada granit Gadung 76 ppm, granit Bebuluh  23,33 ppm, granit Mangol 42 ppm, granit Pemali 35,40 ppm, granit Jebus 85,96 ppm, granit Pelangas 66,73 ppm dan granit Menumbing 67,03 ppm. Secara umum, kondisi fisik batuan granit di lapangan menunjukkan telah mengalami pelapukan tingkat lanjut. Batuan granit yang potensial thorium adalah granit Jebus, Menumbing, Pelangas dari Bangka Barat dan granit Gadung dari Bangka Selatan. Berdasarkan data Pulau Bangka layak dipertimbangkan dalam pengembangan eksplorasi thorium.

Kata kunci: potensi, thorium, granit, Bangka

ABSTRACT

STUDY ON THORIUM POTENTIAL IN GRANITE ROCK ON THE BANGKA ISLAND. In Indonesia generally thorium was found in granite rocks. On the island of Bangka there are quite a lot of granite out crops such as Menumbing granite, Pelangas granite, Jebus granite, Pemali granite, Mangol granite, Bebuluh granite and Gadung granite. The distribution of the granites is extensive enough to be considered as a granite potential thorium. The aim of study is to determine the potential of thorium in granitic rocks located on the Bangka Island. The method used is a heavy mineral sampling of weathered granite rocks, then performed the measurement and analysis of thorium in the laboratory using X-Ray Fluorescence. Granitic rocks are considered potential thorium if thorium content has at least three times the normal levels of thorium in granite (15 ppm) and it has experienced highly weathered so easy to be mined. Results of the study showed levels of thorium in Gadung granite is 76ppm, Bebuluh granite is 23.33ppm, Mangol granite is 42ppm, Pemali granite is 35.40ppm, Jebus granite is 85.96ppm, Pelangas granite is 66.73 ppm and Menumbing granite is 67.03ppm. The observation of the physical condition in the field show that in general all granites have undergone strongly weathered. It was concluded that the potential of thorium granitic rocks are Jebus granite, Menumbing granite, Pelangas granite contained in the West Bangka regency and Gadung granite in South Bangka regency. Based on the data, Bangka Island possible of consideration in the development of thorium exploration.

Keywords: potential, thorium, granite, Bangka