Gravity Survey of Mafic Rocks at Billdal

Abstract

Billdal in southwestern Sweden, is an area dominated by two main rock types, Askim granite and gabbro. Their density difference makes gravity survey an ideal method to help map the location of gabbro bodies which are not close to the surface. With the use of Modelvision, it will also be possible to estimate their volume and get an image of the gabbro plutons in the area. The gravity anomaly results go from a minimum of -1.83 mgal in the northern part to a maximum of 5.77 mgal, located in the central area of Lindås. Several different gabbro models are proposed to explain this extreme gravitaty anomaly.