Bulletin of the Geological Society of Malaysia, Volume 17, Dec.1984, pp. 357 – 371

Analysis of Mesoscopic Structures at Mersing and Tanjung Kempit, Johore, Peninsular Malaysia

K.R. CHAKRABORTY and IAN METCALFE*

Department of Geology, University of Malaya, Kuala Lumpur, Malaysia.

*Present address: 6E, Lorong 16,10C, Petaling Jaya, Selangor, Malaysia.

Abstract: The metasedimentary rocks of possible Upper Palaeozoic age at Mersing and Tg. Kempit are multiply deformed. Using overprinting criteria as well as fold style and orientation, three phases of folding have been recognized, the second phase folds (F₂) being predominant. The structural evolutionary sequence in both the areas is similar, the first phase folds (F₁) are coaxially refolded by F_2, and F₃ folds are later superposed on both F₁ and F₂. Macroscopically F₁ and F₂ folds are nonplane noncylindrical and F₃ folds appear to be plane noncylindrical.

The structural trends of the two areas are at variance. At Mersing, the F₁ and F₂ axial planes strike mainly northwesterly and axial plunge is towards southeast or northwest, while the trends of the F₁ and F₂, axial planes and axial plunge at Tg. Kempit are N to NNE.

F₁ and F₂ axes at Mersing are dispersed. The dispersion pattern may be interpreted as due to the superposition of F₃ folds of slip-type, the slip plane being subvertical and E-W trending with subhorizontal westerly a₃ kinematic axis. Alternatively, bending of the crustal block on a subvertical axis may be responsible for the dispersion of F₁ and F₂ as well as the development of F₃ folds. The difference in structural orientation between Mersing and Tg. Kempit is also explicable in terms of crustal bending. The postulated crustal bending may be envisaged as due to strike-slip motions.

https://doi.org/10.7186/bgsm17198418