DEFORMATION OF BENTONG-RAUB SUTURE ZONE IN NORTH BANGKA ISLAND

• Main Author: Naufan Hendrawan, Rezki
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/33352
• Institution: Institut Teknologi Bandung

The Northern Bangka Island composed by Pemali Metamorphic Complex and S-type Klabat Granite that occured in Early Jurassic – Late Triassic. This zone recorded three deformation representing tectonic events as Permian subduction, Late-Triassic collision, and Cretaceous uplift. The northern part of Bangka Island has an identical rock arrangement with Bentong-Raub Suture Zone in Peninsula Malaysia. Bentong-Raub suture line has a northwest – southeast trend which thought to extend northwest to Thailand and southwest to Indonesia which crossed the northern part of Bangka Island. The study was conducted in the northern part of Bangka Island which focused on the macrostructure and microstructure analysis to determined deformation based on field observation and laboratory analysis with oriented sample qualitatively. The study began by conducting field observation on Pemali Metamorphic Complex and Klabat Granite as objects. Field observation aims to collect lithological data, structural data, and oriented rock samples. The results of field pitching were processed to determine macrostructures, microstructures, and minerals distribution. The data analyzed based on kinematic, descriptive, and deformation mechanisms to determine the deformation patterns that occured in the study area. Field and oriented thin section data show structures that occured in different deformation conditions. The analyzed based on macrostructures and microstructures showed that the northern part of Bangka Island experienced three different deformation phases. Deformation begins with the formation of folds that are associated with collisions between Sibumasu-Indochina, followed by a second deformation that forms a fold with a different verging. Both deformations are formed in the ductile zone and the brittle-ductile transition zone. The third deformation occurs when rocks have been lifted to the surface by the presence of faults, joints, and veins. The sequence of the deformation model is similar to the deformation experienced in the Bentong-Raub suture zone formed in the shear zone.