Porphyry Body and Geological Structure Identification as Control of Low Sulphidation Epithermal System in Sangon, Kokap Sub-District, Kulonprogo Regency, Special Region of Yogyakarta, Indonesia

Akmal Dzulfikar (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Anang Sahroni (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Bachruddin Ashari (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Diah Ayu R (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Erwina Sofia Br Sembiring (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Fadia Zharfa Ash S (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Lilik Maryanto (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Lutfi Afgani (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
M Nurrahman (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
M Rahmat C (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Muslihul Zaim (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Novita Triswi H (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Riando Elang D (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Siti Fadzillah (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)
Ulya Habiburrahman (Geophysics Sub-Department, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada)

Jurnal Fisika Indonesia
Vol 22, No 3 (2018)

There is gravity measurement that is supported by magnetic measurement in Sangon to identify porphyry body and geological structure as low sulfidation epithermal system control. The survey area is 6.4 x 5.6 km for gravity method and 2.5 x 1.2 km for the magnetic method. The value of gravity anomaly after flat plane reduction processing is 122-142 mGal which is positive anomaly located in the north-eastern area and negative anomaly to 82- 102 mGal located in the south-western area. Whereas the magnetic residual anomaly is - 800-1300nT.Conducted 2.5 D modelling of gravity method that is based on local anomaly slice. The result of 2.5D modelling show that an intrusion body interpreted as Dacite intrusion as host rock which plays a role as a heat source of the mineralization system. The density of Dacite is 2.70 gr/cm3. The result of gravity modelling has a correlation with the result of magnetic modelling. Based on magnetic modelling, the intrusion body is located in the south-west.