ANALISIS DATA GEOLISTRIK TIME DOMAIN INDUCED POLARIZATION (TDIP) KONFIGURASI DIPOLE-DIPOLE UNTUK IDENTIFIKASI ZONA MINERALISASI LOGAM (Au-Cu) DI KECAMATAN TIRTOMOYO, KABUPATEN WONOGIRI, JAWA TENGAH

AGMADILA RAHMATIN PS, Dr.rer.nat. Mochamad Nukman, M.Sc. ; Drs. Imam Suyanto, M.Si.

2023 | Skripsi | S1 GEOFISIKA

Indonesia yang merupakan jalur pertemuan lempeng Eurasia, lempeng Indo-Australia dan lempeng Pasifik, menjadikan Indonesia sebagai negara yang kaya akan potensi sumber daya alam akibat dari interaksi ketiga lempeng tersebut. Salah satunya adalah sumber daya komoditas mineral yang menjadi sumber daya komoditas andalan di Indonesia. Potensi sumber daya mineral ini juga banyak tersebar di pulau Jawa, salah satunya di Kecamatan Tirtomoyo, Kabupaten Wonogiri, Jawa Tengah. Penelitian kemudian dilakukan untuk mengidentifikasi kemenerusan zona mineralisasi Au-Cu di Kecamatan Tirtomoyo, tepatnya di Desa Hargosari dan Desa Dawuhan. Penelitian ini dilakukan menggunakan metode polarisasi terinduksi kawasan waktu konfigurasi dipole-dipole dengan spasi antar elekroda a sejauh 10 m dan jumlah n sebanyak 8. Pada pengukuran ini, diperoleh data IP sebanyak 7 lintasan dengan 4 lintasan berlokasi di Desa Hargosari dan 3 lintasan di Desa Dawuhan. Pengolahan dilakukan dengan menggunakan software Res2DInv untuk mendapatkan penampang 2D resistivitas dan chargeabilirtas. Kemudian, dilanjutkan dengan menggunakan software Rockworks 17 untuk memvisualisasikan korelasi antar lintasan di area penelitian. Berdasarkan hasil interpretasi, daerah penelitian dapat diidentifikasi menjadi 4 zona, yaitu top soil/alluvium dengan nilai resisitivitas < 200 Ohm.m dan nilai chargeabilitas <10 ms, zona batuan beku dengan nilai resistivitas > 200 Ohm.m dan nilai chargeabilitas < 10 ms, zona alterasi silisik dengan nilai resistivitas < 200 Ohm.m dan nilai chargeabilitas > 10 ms, zona alterasi logam dengan nilai resistivitas < 80 Ohm.m dan nilai chargeabilitas > 10 ms, serta zona mineralisasi Au-Cu dengan nilai resisitivitas > 80 Ohm.m dan nilai chargeabilitas > 22,5 ms. Zona mineralisasi Au-Cu pada area penelitian di Desa Hargosari menerus dengan orientasi relatif Utara - Selatan. Sementara itu, tidak ditemukan kemenerusan zona mineralisasi Au-Cu pada area penelitian di Desa Dawuhan.

Indonesia, a meeting point for the Eurasian plate, the Indo-Australian plate, and the Pacific plate, makes Indonesia a country rich in potential natural resources due to the interaction of the three plates. One of them is mineral commodity resources, the primary commodity resources in Indonesia. The potential for mineral resources is equally widely spread across the island of Java, one of which is in Tirtomoyo District, Wonogiri Regency, Central Java. To be precise, the research was carried out to identify the continuity of the Au-Cu mineralization zone in Tirtomoyo District, especially in Hargosari Village and Dawuhan Village. This research was conducted using the time domain induced polarization method of dipole-dipole configuration with a spacing between electrodes (a) as far as 10 m and 8 as the n value. In this measurement, IP data were obtained for 7 lines, where 4 lines were located in Hargosari Village and 3 lines in the Dawuhan Village. Processing is carried out using Res2DInv software to obtain 2D resistivity and chargeability cross-sections. Then, it is continued by using Rockworks 17 software to visualize the correlations between the lines in the study area. Based on the interpretation results, the study area can be identified into 4 zones, topsoil/alluvium with a resistivity value of < 200 Ohm.m and a chargeability value of <10 ms, igneous zone with a resistivity value of >200 Ohm.m and a chargeability value of <10 ms, silicic alteration zone with resistivity values < 200 Ohm.m and chargeability values >10 ms, metal alteration zones with resistivity values < 80 Ohm.m and chargeability values >10 ms, and Au-Cu mineralization zones with resistivity values >80 Ohm.m and chargeability values >22.5 ms. The Au-Cu mineralization zone in the research area in Hargosari Village is continuous with a relatively North-South orientation. Meanwhile, no continuity of Au-Cu mineralization zones was found in the research area in Dawuhan Village.

Kata Kunci : Polarisasi Terinduksi, mineralisasi Au-Cu, resistivitas, chargeabilitas