Bulletin of the Geological Society of Malaysia, Volume 45, May 2002, pp. 235 – 242
1Department of Geology, University of Malaya, 50603, Kuala Lumpur
2School of Earth Sciences, Victoria University of Wellington, New Zealand
Abstract: Mesozoic mafic dykes in the Perhentian islands and their surrounding area can be divided into two types, based on their field occurrence, i.e. the older and younger dykes. The older dykes are synplutonic to their felsic host and the younger dykes post date their felsic host. The younger dykes, which are more abundant, are mainly doleritic in composition and are similar to those found throughout the Eastern Belt of Peninsular Malaysia. They are made up of plagioclase, clinopyroxene, amphibole, iron ore and chlorite. The silica content of the dykes is between 47.17 to 53.7% and can be classify as basalt, trachybasalt and basaltic trachyandesite. Geochemical study shows that the younger dykes formed in a continental within plate tectonic setting.