Gravity survey of the Layang-Layang Tertiary Basin in Johor, Peninsular Malaysia - A preliminary report

Abstract

A gravity survey was carried out in the middle of 1988 to determine the structure of the Layang-LayangTertiary Basin which is the southern most of the known Tertiary basins in Peninsular Malaysia. The survey covered 549 stations over an area of 45 km by 23 km and included the entire area geologically mapped as the Tertiary Layang-Layang formation and part of the Pre-Tertiary Tebak, Sedili and Linggiu formations to the east. Measurements over the granitic area surrounding the basin provided regional control. The results show a prominent negative gravity anomaly with a maximum amplitude of20 mgals covering an area of 165 sq. km which includes the Tebak formation as well as the Layang-Layang formation. The anomaly is centred within the Tebak formation about 2 km from the boundary of the Layang-Layang formation where the Bouguer anomaly value reaches-9 mgals.