Ground Gravity Survey At Dixie Valley Geothermal Field Area (Blackwell, Et Al., 2009)

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Exploration Activity: Ground Gravity Survey At Dixie Valley Geothermal Field Area (Blackwell, Et Al., 2009)

Exploration Activity Details
Location Dixie Valley Geothermal Field Area
Exploration Technique Ground Gravity Survey
Activity Date

Usefulness useful
DOE-funding Unknown

"The gravity data are described by (Blackwell et al., 1999; 2002). On a basin-wide scale the gravity low in Dixie Valley is strongly asymmetrical from east to west. The west side is relatively well-defined by rapid horizontal changes in the gravity anomaly value, whereas along the east side horizontal changes are more subdued and often consist of several steps. The horizontal gradient of the gravity field has proved most useful in identifying the surface projection of subsurface contacts of greatest density contrast, (Blackwell et al., 2002). Thus where the contact is sharp and large the gravity gradient shows a high value, but in areas with shallow features or small density contrasts, the gravity gradient high represents the midpoint over that feature. The terrain slope is the slope of the contours in the direction of steepest descent so it locates the magnitude and direction of the steepest gradient in any area of the map. The gravity gradients have been used to constrain the positions of faults cutting the piedmont block. Modeling of the gravity data (Blackwell et al., 1999; 2002) shows that along much of the steep east side of the Stillwater Range, piedmont faults in the valley, not the fault defined by the topography accommodate most of the displacement between the range front and the valley bottom. The pattern of the residual gravity and the gravity gradients along the eastern side of the basin is complex and in general not parallel to the edge of the valley. In that area the presence of the dense Jurassic Humboldt mafic complex complicates the pattern and combined magnetic and gravity interpretation is needed to analyze the structure. Details of the analysis will be described in Blackwell et al. (2010)."


Additional References