Implications of the Bok Bak Fault movements on the structure and lithostratigraphy of the Pokok Sena area

Abstract

Exposures of the Lower and the Upper Paleozoic sediments in the Pokok Sena area were recognised as equivalent to the Mahang and the Kubang Pasu Formation respectively. The Mahang Formation consists of mainly weathered slate, and minor siliceous mudstone and chert. The lower part of the exposed Kubang Pasu Formation comprises dark laminated mudstone and dark grey chert. The sequence is overlain by interbedded mudstone and sandstone. Thick sandstone interbedded with thin shale represents the upper part ofthe formation. The area has topographically asymmetric NNW ridges with W-vergent thrust faults and oblique lateral faults. Exposures at several localities display the slate of the Mahang Formation overlies the younger Kubang Pasu Formation. The formations are separated by moderately steep reverse faults. Merging and combination of lateral slips and reverse movements reflects a transpressional deformation within the Paleozoic sediments. A flower geometry is defined by vertical to steeply dipping lateral faults which have shallow plunging slickensides and moderately steep dipping reverse faults.