Kinematic analysis of striated fractures in Titiwangsa granitoid, Karak Highway - Selangor side


Author : H.D. TjiaPublication : Bulletin of the Geological Society of MalaysiaVolume : 35Page : 25-35Year : 1994


Description

Bulletin of the Geological Society of Malaysia, Volume 35, July 1994, pp. 25-35

 

Kinematic analysis of striated fractures in Titiwangsa granitoid, Karak Highway - Selangor side

H.D. TJIA

Universiti Sains Malaysia, Pulau Pinang

 

Abstract: Reliable fault-sense indicators: bruised steps, pluck steps, accretionary steps, stoss spalls, trail ridges, fault roche moutonnee, prod depressions and prod ridges establish the nature of motion on slickensided fracture planes in Titiwangsa granitoid along the Karak Highway. In certain instances subsidiary structures: en echelon tension gashes and drag features, and fault separations provide additional information on the sense of fault motion.

Right lateral and left lateral fault motion took place most frequently along NNE-NE and along ENE-E trending, steeply inclined to vertical fractures, respectively. This movement pattern is consistent with maximum horizontal compression within the 33° to 48° sector, which deviates about 20° from the direction of regional compression that affected Peninsular Malaysia, but is compatible with the vergence of the Genting Thrust Belt. Therefore, contemporarily of thrusting and lateral fault motion on these particular fractures is indicated.

Among those studied, a comparatively small number of vertical fractures indicates lateral motion in response to compression that acted approximately perpendicular to that in the established sector. It appears that the NW-SE compression resulted from relaxation of the NE-SW maximum horizontal stress. Superimposed striations and other fault markings on a number of fracture planes represent isostatic adjustments through gravity faulting.