Groundmagnetic survey used to identify the weathered zone, in Blang Bintang, Aceh, Indonesia

Abstract

The objective of a geomagnetic survey is to investigate subsurface characteristic of geology, especially the weathered zone on the basis of the anomalies in the earth’s magnetic field resulting from the magnetic properties of the underlying rocks. The magnetic properties of rocks called as magnetic intensity is extremely variable depending on the type of rock and the environment of the region. The result of the research shows that the local magnetic intensity varies of -697 nT and 484 nT in the study area 1 and about -697 nT and 103 nT in the study area 2 whichare indicative of weathered zones. The weathered zones were interpreted by highly magnetic contrast. The total magnetic anomaly of Blang Bintang, Aceh Besar (Indonesia) shows higher magnetic anomalies over the eastern part (area 1) and low magnetic anomalies in the western part (area 2) of the study area, which indicate the presence of weathered zonedue to the presence of sediments such as clay, gravel and schist within the zone. The study has shown that magnetic method could be used as an efficient tool for delineating weathered zone in a study area.