A new isostatic residual gravity map of the conterminous United States

By: , and 



In order to display more clearly the gravity anomalies caused by bodies of geologic interest in the crust, a new colored isostatic residual gravity map of the conterminous United States has been prepared using the gravity data set compiled for the Gravity Anomaly Map of the United States (SEG, 1982). The isostatic residual map is based on an Airy-Heiskanen model of local compensation, with the surface load requiring compensation being defined by 5-minute topographic and bathymetric data sets. Because topography-related anomalies have been removed to first approximation, the resulting isostatic residual map highlights density contrasts associated with geologic bodies in the crust. For example, the 2000 km-long gravity high that follows the Appalachian orogenic belt is delineated along its entire length without the topographic overprint characteristic of Bouguer maps. For purposes of displaying gravity anomalies caused by shallow bodies of geologic significance, the nature of the isostatic model and the values of its parameters are of lesser importance than the application of an isostatic correction of some sort. Most isostatic models will result in residual maps which appear very similar in their main patterns and features. Anomalies on isostatic residual gravity maps should not be casually interpreted in terms of "undercompensation" or "overcompensation" because large amplitude anomalies can be produced by crustal bodies in complete local isostatic equilibrium.

Publication type Conference Paper
Publication Subtype Conference Paper
Title A new isostatic residual gravity map of the conterminous United States
DOI 10.1190/1.1892727
Volume 4
Issue 1
Year Published 1985
Language English
Publisher SEG
Contributing office(s) Crustal Geophysics and Geochemistry Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Description 2 p.
First page 197
Last page 198
Conference Title 55th Annual International SEG Meeting
Conference Location Washington, DC
Conference Date October 6-10, 1985
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