Deep crustal profile across NW Sabah basin: integrated potential field data and seismic reflection

Abstract

The crustal model has been created from the integration of potential field data and complemented by multichannel reflection seismic profiles, allowing the interpretation of five tectono-stratigraphy provinces of Deepwater Fold and Thrust Belt, Sabah Trough, Dangerous Grounds Province and Thrust Sheet Zone. The free-air and magnetic anomaly was published from satellite altimetry data. Seismic interpretation displays structural anticline that indicate fold and thrust zone as the Sabah Trough frontier to the southeast. The formation of half-grabens and normal faults was clearly indicated extension in the entire Dangerous Grounds which subducted beneath to the Sabah Trough. The crustal modelling was used to describe and determine the Moho thickness and the configuration of deeper crustal layer by using the GM-SYS Profile Modelling software. The range of Moho thickness shows slightly variable between 33 and 26 km across of the study area. Analytical signal analysis estimated the depth of magnetic source range between 26 and 33 km disclosed to upper crust. The high density surrounded by low density body at Thrust Sheet Zone interpreted as a thrust block built of Palaeogene Crocker sediment.