Analisis Sebaran Endapan Porfiri Berdasarkan Data Aeromagnetik, Suseptibilitas Magnetik Dan Mineralisasi Pada Prospek "X"

Avrilla, Vicka Winda (2025) Analisis Sebaran Endapan Porfiri Berdasarkan Data Aeromagnetik, Suseptibilitas Magnetik Dan Mineralisasi Pada Prospek "X". Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Endapan porfiri terbentuk melalui proses magmatik-hidrotermal yang berasosiasi dengan intrusi kompleks batuan berkomposisi intermediate hingga felsik. Endapan ini merupakan salah satu sumber utama logam dunia, khususnya tembaga, emas, dan molibdenum. Pembentukan endapan ini umumnya berasosiasi dengan busur magmatik, seperti pada busur Sunda bagian timur. Potensi mineralisasi di wilayah tersebut mendorong eksplorasi lanjutan, termasuk pada prospek 'X' yang dikelola oleh PT Bumi Suksesindo dan menjadi fokus dalam penelitian ini. Salah satu metode eksplorasi yang dapat digunakan yaitu metode magnetik dengan memanfaatkan variasi anomali magnetik. Tujuan penelitian ini yaitu untuk mengetahui persebaran anomali magnetik berdasarkan pengukuran aeromagnetik serta mengidentifikasi persebaran endapan porfiri berdasarkan pemodelan suseptibilitas magnetik, kandungan mineral molibdenum (Mo) dan besi (Fe). Perangkat yang digunakan dalam pengambilan data aeromagnetik meliputi drone DJI Matrice 600 Pro, magnetometer base GSM-19/19F, serta magnetometer drone GSMP-35U dengan didapatkan sebanyak 405.601 data aeromagnetik. Kemudian, data suseptibilitas magnetik diperoleh dengan menggunakan alat suseptibilitas meter KT-10R S/C . Sementara itu, data geochemical assay Mo dan Fe didapatkan dari hasil uji laboratorium. Data aeromagnetik yang diperoleh kemudian dilakukan pengolahan menggunakan software pengolahan data magnetik untuk menghasilkan peta anomali regional dan peta analytic signal. Kemudian, untuk memetakan distribusi anomali magnetik bawah permukaan dilakukan proses inversi tiga dimensi. Sementara itu, data geochemical assay Mo dan Fe dimodelkan secara tiga dimensi menggunakan metode interpolasi Radial Basis Function (RBF) pada software pemodelan 3D sehingga dapat dilakukan korelasikan dengan hasil inversi 3D magnetik. Hasil penelitian ini, menunjukkan sebaran anomali magnetik tinggi berada pada area tengah lokasi penelitian yang menunjukkan bentuk batas melingkar atau disebut dengan circular feature. Anomali magnetik tinggi tersebut mengindikasikan adanya asosiasi dengan kandungan mineral magnetit yang terbentuk sebagai hasil dari alterasi hidrotermal dalam zona potasik yang terletak pada zona inti porfiri. Selain itu, berdasarkan hasil korelasi pemodelan 3D, section RS (area kanan) menunjukkan adanya korelasi kuat antara inversi 3D magnetik, suseptibilitas magnetik, dan kandungan Mo, meskipun model distribusi Fe pada section ini belum menunjukkan korelasi signifikan akibat terbatasnya data bor. Sedangkan, pada section VW (area kanan) dan XY (area kanan), hasil inversi 3D magnetik kurang menunjukkan adanya korelasi yang signifikan disebabkan kekosongan data pengukuran aeromagnetik. Hasil penelitian ini diharapkan memberikan kontribusi signifikan dalam pengembangan strategi eksplorasi yang lebih efisien dan efektif berbasis distribusi endapan porfiri.
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Porphyry deposits are formed through magmatic-hydrothermal processes associated with the intrusion of intermediate to felsic rock complexes. These deposits represent one of the world’s primary sources of metals, particularly copper, gold, and molybdenum. Their formation is generally linked to magmatic arcs, such as the eastern segment of the Sunda Arc. The mineralization potential in this region has driven continued exploration, including at the “X” prospect managed by PT Bumi Suksesindo, which is the focus of this study. One of the exploration methods employed is magnetic surveying, which utilizes variations in magnetic anomalies. This study aims to delineate the distribution of magnetic anomalies based on aeromagnetic measurements and to identify porphyry deposit distributions through modeling of magnetic susceptibility, and molybdenum (Mo) and iron (Fe) concentrations. The aeromagnetic data were acquired using a DJI Matrice 600 Pro drone, a GSM-19/19F base magnetometer, and a GSMP-35U drone magnetometer, yielding a total of 405,601 data points. Magnetic susceptibility data were obtained using a KT-10R S/C susceptibility meter. Meanwhile, geochemical assay data for Mo and Fe were derived from laboratory analysis. The aeromagnetic data were processed using magnetic data processing software to generate regional anomaly maps and analytic signal maps. Three-dimensional inversion was then conducted to map subsurface magnetic anomaly distributions. Additionally, geochemical assay data for Mo and Fe were modeled in 3D using the Radial Basis Function (RBF) interpolation method in 3D modeling software, enabling correlation with the 3D magnetic inversion results. The results indicate that high magnetic anomalies are concentrated in the central part of the study area, forming a circular feature. These high anomalies are interpreted to be associated with magnetite mineralization, likely formed due to hydrothermal alteration within the potassic zone, which represents the core of the porphyry system. Furthermore, based on 3D modeling correlations, the RS section (right area) exhibits a strong correlation among the 3D magnetic inversion, magnetic susceptibility, and Mo concentrations, although the Fe distribution model in this section does not show significant correlation due to limited drillhole data. In contrast, the VW (right area) and XY (right area) sections show weak correlation with the 3D magnetic inversion, likely due to gaps in aeromagnetic data coverage. This research is expected to contribute significantly to the development of more efficient and effective exploration strategies based on the distribution of porphyry deposits.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Aeromagnetic Method, Ferrum, Magnetic Susceptibility, Molybdenum, Porphyry, Besi, Endapan Porfiri, Metode Aeromagnetik, Molibdenum, Suseptibilitas Magnetik
Subjects:	Q Science > QE Geology > QE1.F557 Magnetic anomalies--Measurement. Q Science > QE Geology > QE601 Geology, Structural T Technology > TN Mining engineering. Metallurgy > TN269 Prospecting--Geophysical methods
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Avrilla Vicka Winda
Date Deposited:	07 Jul 2025 04:15
Last Modified:	08 Jul 2025 02:14
URI:	http://repository.its.ac.id/id/eprint/119390

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