Pola Tahanan Jenis dan Konduktivitas Batuan Mengandung Mineral Radioaktif di Botteng dan Takandeang, Mamuju, Sulawesi Barat

Adi Gunawan Muhammad, Frederikus Dian Indrastomo, I Gde Sukadana

DOI: http://dx.doi.org/10.17146/eksplorium.2017.38.1.3540

Sari


Abstrak

Kegiatan penyelidikan umum mineral radioaktif di daerah Mamuju, Sulawesi Barat merupakan tindak lanjut dari hasil pengukuran radioaktivitas lingkungan yang menunjukkan adanya nilai radioaktivitas tinggi. Kandungan mineral radioaktif yang cukup tinggi ditemukan antara lain di Desa Botteng dan Desa Takandeang yang tersusun oleh batuan berkomposisi leusit-basal tetapi karakteristik bawah permukaan daerah ini belum diketahui. Untuk mengetahui karakteristik geologi bawah permukaan, terkait dengan mineralisasi Uranium dan Thorium di daerah Botteng dan Takandeang, pengukuran geofisika menggunakan metode tahanan jenis dan polarisasi terimbas (Induced Polarization/IP) dilakukan. Pengukuran tersebut dilakukan menggunakan konfigurasi Wenner dan dipole-dipole, dimulai dengan pembuatan enam jalur pengukuran, masing-masing tiga jalur: GF/BTGY-01, GF/BTGK-02, dan GF/BTGK-04 di Botteng, dan tiga jalur lainnya: GF/TKDK-01, GF/TKDK-07, dan GF/TKDY-06 di Takandeang. Pengukuran dilakukan dengan memotong arah kemenerusan anomali radiometri permukaan. Hasil pengukuran menunjukkan keterdapatan anomali berada pada sebaran batuan autobreksia yang terlihat jelas di lokasi GF/TKDY-6, GF/TKDK-07, dan GF/BTGK-04. Beberapa indikasi mineralisasi di permukaan teridentifikasi di penampang GF/BTGK-02 dan GF/TKDK-01, dicirikan dengan anomali-anomali chargeabilitas >25,14 ms di lintasan GF/BTGK-02 dan 81,4 ms di GF/TKDK-01. Anomali yang signifikan direkomendasikan sebagai lokasi pemboran.

 

Abstract

The general investigation activities of radioactive minerals in Mamuju Area, West Sulawesi is a respon of the environmental radioactivity measurement result, which shows the existence of high radioactivity value. High radioactive mineral content found in Botteng and Takandeang Villages. From the outcrops, they composed of leucite-basalt rocks; meanwhile the subsurface characteristics of this area are unknown. To characterize the subsurface geology, related to uranium and thorium mineralization in Botteng and Takandeang area, geophysical measurement conducted using resistivity and Induced Polarization (IP) methods. The measurements carried out using Wenner and dipole-dipole configurations. The measurements started with the creation of six measurement paths where three lines: GF/BTGY-01, GF/BTGK-02, and GF/BTGK-04 are in Botteng and three other lines: GF/TKDK-01, GF/TKDK-07 and, GF/TKDY-06 are in Takandeang. Measurements conducted by crossing the surface radiometric anomaly distribution. The result showed anomaly occurences on autobreccia distribution in GF/TKDY-6, GF/TKDK-07, and GF/BTGK-04 locations. Several mineralization indication on surface identified in GF/BTGK-0, and GF/TKDK-01 sections, charaterized by chargeability anomalies more than 25.14 ms and 81.4 ms respectively. All significant anomalies are recomended as drilling location.


Kata Kunci


Geolistrik; tahanan jenis; chargeabilitas; uranium; thorium; Mamuju

Teks Lengkap:

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Referensi


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