Original paper

Examples from studies of residual and regional gravity maps to delineate deep controls of mineralization in the western United States

Kutina, Jan

Global Tectonics and Metallogeny Volume 3 Number 2-3 (1989), p. 189 - 192

9 references

published: Jan 1, 1988

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Abstract

The filtering of Bouguer gravity anomaly maps separates, in a substantial way, gravity anomalies originating from geological bodies of different sizes which occur at different depths. Some anomalies are not easily recognizable in the unfiltered Bouguer gravity maps, because of superposition of gravitational effects of the individual bodies. In our metallogenic study we have used maps with different wavelength cutoffs: 250 km, 625 km and 1000 km. The 250-km wavelength cutoff provides shortwavelength (residual) anomalies arising from local, near-surface masses, essentially reflecting the mass distribution in the crust, and long-wavelength (regional) anomalies originating from larger features from any depth. The 1000-km wavelength cutoff breaks down the unfiltered Bouguer anomaly map into one residual map which includes all gravity anomalies of a size 1000 km and less, and one regional map showing the largest anomalies > 1000 km, which were masking the pattern of the residual anomalies. Both the above residual and regional gravity anomaly maps with different wavelength filtering proved to be very useful in the study of deep controls of mineralization. Two examples of the utility of residual maps and two examples of the utility of regional maps are given below.

Keywords

western United Statesmineralization