Delineation of Gold Prospecting Area Based on Total Magnetic Field Anomalies Reduction to The Pole

Alvin Caesar Lesmana Ikramsyah, Nazli Ismail, Ibnu Rusydy, Agus Pajrin Jaman

Abstract


Telah dilakukan reduksi ke kutub data anomali medan magnetik total untuk mendelineasikan area prospek emas. Intensitas medan magnetik total dikoreksi dengan nilai diurnal dan IGRF untuk mendapatkan anomali medan magnetik total. Reduksi ke kutub anomali medan magnetik total dilakukan untuk menyederhanakan pola kontur anomali di ekuator. Anomali medan magnetik total reduksi ke kutub telah difilter untuk mendapatkan anomali residual yang merefleksikan target benda anomali pada kedalaman yang dangkal. Hasil yang didapat menunjukkan kontur anomali medan magnetik total reduksi ke kutub terlihat lebih sederhana dan mudah untuk diinterpretasi. Aplikasi kedua metode tersebut pada daerah “C” di Jawa Barat telah berhasil diterapkan. Pada low pass filter anomali yang muncul menunjukkan pola smooth yang merupakan efek dari benda anomali regional. Pada anomali residual menunjukkan pola efek dari benda anomali yang dangkal. Nilai anomali medan magnetik total residual yang rendah pada lokasi penelitian diprediksi sebagai tempat terdepositnya emas yang berasosiasi dengan patahan dan zona alterasi yang berada di bagian selatan dan barat lokasi penelitian.

Delineation of gold prospecting area based on the total magnetic field anomalies reduction to the pole have been done. The total magnetic field intensity data were corrected by diurnal and IGRF to obtain the total magnetic field anomalies. The total magnetic field values were reduced to the pole to simplify contour shceme in equator and filtered to obtain the residual anomalies which are reflected as shallow depth anomalies. The results showed that the reduction to the pole contour were more simple and easily to be interpreted. Application of both methods in area "C" at West Java Province has been successfully delineating gold deposit in the area. In low pass filter the anomalies showed smooth pattern which are representated as regional effects. The residual anomalies appear as near surface effects. The low magnetic values in the residual data be expected as gold deposit which associated with fault and alteration zones where located in south and west section of the research field.

Keywords: magnetic method, the total magnetic field anomalies, reduce to the pole, low pass  filter, gold potential



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References


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