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The western foothills area of Gunung Ledang is underlain by a predominantly pelitic group and a calc-silicate group of rocks. The former is made up of both spotled and nonspoiled pelitic hornfclses with minor metavolcanics and calc-silicate hornfels. The laller is predominantly calc-silicate Ilornfels. metavoleanies and tllin-banded ellIe-silicate hornfels and amphibolite. Minor rock types in the calc-silicate group arc marble. amphibolite and pelitic hornfelscs. These layered rocks are invaded by the Late Cretaceous Lcdang granite on the east and the Belading granite on the west. There is evidence of an early regional metamorphism registered in the rocks as reliet Sl;histositles and preferred mineral orientation. This episode is believed to be low grade. A second episode of contact metamorphism gave rise to the formation of minerals such as cordierite. sillimanite. andalusite. diopside. forsterite and wollastonite. This is followed by polymetasomatism giving rise to development of axinite. vesuvianite. lime garnet. seapoJite. chondrodite and prchnite. MetamorphiC zonations arc shown by the contact metamorphism and polymetasomatism. II is speculated Ihat the regional metamorphism is a Middle-Lute Triassic event if the layered rocks are extensions of the Middle-Late Triassic Gemas beds. The other metamorphic episodes are coeval with lhe Ledang intrusion of Late Cretaceous age. INTRODUCTION This paper presents evidence for the occurrence of some metamorphic episodes in the western foothills area ofGunung Ledang(Mt. Ophir), Johore-Malacca (Fig. I) and gives a brief account of the geology. The area concerned is of about 40 sq. km from Bukit Asahan in Malacca to lhe Bekoh Estate area about 2 km north of Tangkak, Johore. The area concerned is part of a larger area mapped in field mapping exercises by several staff and almost all the Third Year students of the Dept. ofGeology. University of Malaya since 1976. Staff who have participated in the field mapping are Dr. B.K. Tan (1976-81), En. J.K. Raj (1977-78), En. Samsudin Hj. Taib (1979), En. K.L. Low (1980-81) and the author (1976-81). The combined efforts of all involved in Ihe field mapping have contributed towards unravelling the geology of the area which is structurally and petrologically both complex and challenging. GEOLOGICAL SETTING Thearea lies in the Central Belt of Peninsular Malaysia near or at the western margin of the Belt (Fig. 2) The rocks of the western foothills have been invaded by the high level Ledang granite found by Yap (1981) to be emplaced in the Late Cretaceous t69 Ma). Various publications have the Lower Palaeozoic Foothills Formation bordering Presented at GSM Regional Geology Seminar April 1981

Metamorphic episodes of the western foothills of Gunung Ledang (Mt. Ophir), Johore-Malacca, with a background account on the geology