RESOLVING BOUGUER ANOMALIES IN CONTINENTS - A NEW APPROACH

Nature of anomalies present in free air gravity and their correspondin g anomalies in Bouguer gravity over continents are analysed in light o f isostatic compensation of topographic masses. These anomalies are cl assified into regional, residual and local and criteria are evolved to identify them. The regional anomaly corresponds to regional topograph y that is compensated. The local anomaly is related to local topograph ic relief. Residual anomaly is caused by subsurface anomalous source i n the form of excess or deficit mass and which is of our interest. A n ew approach is suggested wherein using zero free air values, regional, residual and local anomalies could be separated. This is illustrated for two gravity profiles where the residuals obtained are compared wit h isostatic anomalies. Limitations of this method are discussed.