Exploration Technique: Aeromagnetic Survey
|Exploration Technique Information|
|Exploration Group:||Geophysical Techniques|
|Exploration Sub Group:||Magnetic Techniques|
|Parent Exploration Technique:||Magnetic Techniques|
|Information Provided by Technique|
|Stratigraphic/Structural:||map structure, basin fill thickness, and magnetic mineral concentrations in ore bodies|
|Low-End Estimate (USD):|| 22.532,253 centUSD |
2.253e-8 TUSD / mile
|Median Estimate (USD):|| 167.3416,734 centUSD |
1.6734e-7 TUSD / mile
|High-End Estimate (USD):|| 1,126.30112,630 centUSD |
1.1263e-6 TUSD / mile
|Low-End Estimate:|| 0.26 days7.118412e-4 years |
0.00854 months / 100 mile
|Median Estimate:|| 0.86 days0.00235 years |
0.0283 months / 100 mile
|High-End Estimate:|| 2.33 days0.00638 years |
0.0766 months / 100 mile
- Mapping Structure
- In geothermal exploration, magnetic surveys are used to determine basement depth and to locate concealed intrusive, faults, and areas of hydrothermal alteration.
- Intrusive rocks are associated with magnetic highs (alternatively sedimentary rocks are associated with lows); while the location of faults and zones of hydrothermally altered rocks are associated with magnetic lows.
- In general, the use of magnetic methods provide useful first-order datasets that can be used to define prospects in a broad context.
- On a regional scale, aeromag data has flown at 2-5 km line spacings over much of the western U.S.
- Higher resolution, prospect-scale data is typically collected at constant, low elevation (80-150 m above ground surface) on 0.25-0.50 km line spacings using an ultra-light aircraft.
- As with gravity data, magnetic results are rarely unique and other data are needed to fully interpret and understand them.
- As a standalone method, magnetic surveys tend to be less informative than other methods due to low depth of penetration and resolution, complexity of interpretation, and insensitivity to the presence of water.
- Joint inversion of magnetic data with gravity or other geophysical data types, however, makes it more useful.
- In the past, magnetic surveys were used to determine Curie isotherm depths (i.e., the depth at which temperatures are high enough to cause rock demagnetization), which could be used to indicate depth to thermal anomalies, but subsequent work has proven otherwise.
- (Goldstein 1988) Subregional and Detailed Exploration for Geothermal-Hydrothermal Resources in Geothermal Science and Technology
- (Bruhn et al 2010) "Geothermal Energy Systems: Exploration, Development, and Utilization"
- Baltazor Hot Springs Area
- Blue Mountain Geothermal Area
- Chena Geothermal Area
- Clear Lake Area
- Coso Geothermal Area
- Dixie Valley Geothermal Area
- Glass Buttes Area
- Hualalai Northwest Rift Area
- Kawaihae Area
- Kilauea East Rift Geothermal Area
- Kilauea Southwest Rift And South Flank Area
- Kilauea Summit Area
- Lightning Dock Area
- Maui Area
- Mauna Loa Northeast Rift Area
- Mokapu Penninsula Area
- Mt Princeton Hot Springs Geothermal Area
- Mt St Helens Area
- Raft River Geothermal Area
- Roosevelt Hot Springs Geothermal Area
- Waunita Hot Springs Geothermal Area
- Yellowstone Caldera Geothermal Region