A case study in the resolution of depth extent in modelling of magnetic anomalies over shallow sources in rugged terrain

Abstract

A high resolution helimag survey flown for a coal resource study in rugged terrain near Rylestone in New South Wales revealed several high amplitude anomalies, some coincident with hilltops. The principal objective in interpretation of these anomalies was to determine whether they are due to volcanic layers of restricted depth extent overlying the coal measures, or due to intrusive bodies that cut through the coal measures. It was not possible to reliably discriminate between these sources by inspection of the grid or profile data, and to constrain source depth extent it was necessary to model each anomaly.