IDENTIFIKASI ZONA MINERALISASI EMAS BERDASARKAN DATA CONTROLLED SOURCE AUDIO-FREQUENCY MAGNETOTELLURICS (CSAMT) DENGAN DATA PENDUKUNG INDUCED POLARIZATION (IP) DI LAPANGAN AU

Kholilur Rahman, Syamsurijal Rasimeng, Nandi Haerudin

Abstract


ABSTRAK

 

Telah dilakukan penelitian identifikasi zona mineralisasi emas di sebelah Timur Laut Kubah Bayah, Pongkor, Jawa Barat. Penelitian dilakukan menggunakan metode CSAMT yang didukung oleh data induced polarization (IP) dan geologi lokal daerah penelitian. Batuan induk yang mendominasi di daerah penelitian adalah batuan tuff, batuan breksi dan intrusi andesit. Zona mineralisasi emas terbagi menjadi dua zona, pada zona resistivitas tinggi berkisar 500-1000 Ωm di kedalaman 0-600 meter yang diduga berasosiasi dengan alterasi silisifikasi. Pada zona resistivitas sedang-tinggi berkisar 300-700 Ωm di kedalaman 0-450 meter, diduga merupakan respon dari batuan breksi yang melingkupi intrusi andesit pada proses pembentukannya. Dengan nilai PFE berkisar 2,6-3,4 % yang diduga pada zona tersebut memiliki kandungan logam yang tinggi. Dari interpretasi tersebut, dapat dilihat kemenerusan zona mineralisasi emas dan rekomendasi titik pengeboran eksplorasi sebagai pertimbangan kegiatan penambangan emas di daerah penelitian. Kemenerusan zona mineralisasi emas dari seluruh lintasan pengukuran berarah Barat Laut-Tenggara yang memotong lintasan pengukuran serta sesuai dengan arah singkapan vein. Terdapat enam rekomendasi titik pengeboran tahap eksplorasi di zona mineralisasi emas, pada resistivitas berkisar 500-1000 Ωm dan 400-700 Ωm, serta tepat berada di singkapan vein dan sekitar struktur geologi.

 

ABSTRACT

 

The research has identified the gold mineralization zone in the Northeast of the Bayah Dome, Pongkor, West Java. This study aims to determine the zone of gold mineralization and recommendation of drilling points, as well as the continuity of the gold mineralized zone in the research area based on the geophysical measurement data. The research was conducted using CSAMT method supported by data of induced polarization (IP) and local geology of research area. The dominant rocks in the study area were tuff, breccia and andesite intrusions. The zone of gold mineralization is divided into two zones, in high resistivity zones ranging from 500-1000 Ωm at depths of 0-600 meters allegedly associated with silicified alteration. In medium-high resistivity zones ranging from 300-700 Ωm at depths of 0-450 meters, it is thought to be the response of breccia rocks that surround the andesite intrusion in the formation process. With PFE values ranging from 2.6 to 3.4% which is suspected in the zone has a high metal content. From these interpretations, it can be seen the continuity of the gold mineralization zone and the recommendation point of exploration drilling as consideration of gold mining activities in the research area. The severity of the gold mineralized zone from all trajectories of Northwest-Southwest trending measurements that cut through the measurement path as well as in the direction of the vein outcrop. There are six recommendations of exploration stage exploration points in the gold mineralized zone, at resistivity ranging from 500-1000 Ωm and 400-700 Ωm, as well as precisely located in the outcrop of vein and surrounding geological structures.

 

Keywords: gold mineralization, pongkor, resistivity, CSAMT, PFE, IP.

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DOI: http://dx.doi.org/10.23960/jge.v3i1.1027

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