Gravity and Magnetic Interpretation of Azufral Volcano Geothermal Zone
Miguel A. BELTRAN
The geothermal area of Azufral, located in the department of Nariño in the south west part of Colombia, presents a relevant geothermal potential; in the process of geophysical exploration of the zone, field trips of acquisition of gravity and magnetic data were carried out. From the acquisition of gravity and magnetic data in the geothermal area, accomplished by Quintero, Gomez and Ponce (2008), total Bouguer anomaly and total field magnetic anomaly grids are generated for the area. The depth of source is estimated for total Boguer anomaly and total magnetic field grids and according to the fundamentals of Spector & Grant (1970), is obtained a depth of 4 Km for gravity data and 2.3 Km for reduced to pole magnetic data. From these estimations the regional-residual separation is achieved, using an upward continuation filter. The calculation of analytical signal, tilt angle, Werner deconvolution and the favorability indices is implemented, from the interpretaion of these new grids, the following is concluded: In the area of the Azufral Volcano body, the gravimetric source depth is 600 to 850 m and the magnetometric source depth is 1200 m to 1500 m. The space generated by the Guachucal and Cali-Patía faults affects deep basement zones in the south west part of the study area, generating a deposit basin. In the West part of the Azufral volcano and partially controlled by a segment of the Guabo River fault, there is possibly another intrusive body detected with favorability indices and according to Werner's deconvolution for magnetometry, intrusive body has a depth of 750 m. According to Werner's deconvolution applied over gravity griuds, a sunken block is inferred in the southern part of the Sapuyes - Las Juntas basin, its depth is approximately of 1500 m ; the south west part of the Guachucal fault has a possible deposit zone with a depth of approximately 1500 m to 2000 m. In the north west direction of the municipality of Túquerres, there is a possible intrusive body, with an approximate depth of 550 m - 650 m, linked to an opening area in the village of Santander. This zone has a great possibility to function like a deposit zone of hot fluids.
|        Topic: Geophysics||Paper Number: 13186|