A preliminary analysis of the gravity anomaly field in the Timmins-Senneterre mining areas

Abstract

The results of gravity surveys made by the Dominion Observatory, during the period 1946 to 1963, in the Timmins-Senneterre mining area of Ontario and Quebec are presented as a Bouguer anomaly map (scale: 1: 500, 000). The area is studded with many granite batholiths of variable composition which are outlined by intense negative gravity anomalies . The whole region is regarded as one great roof pendant and on the assumption that the volcanic and sedimentary rocks of the area are everywhere floored by granite , it is possible to estimate the thicknesses of the volcanic belts using the gravity results; however, the depths to which the granite extends cannot be determined by the gravity method alone. A preliminary interpretation using two- and three-dimensional models to simulate major geological bodies indicates that many of the dense volcanic belts in the area extend to depths of from 3 to 5 km.