Petrology and geochemistry of igneous rocks from southern tioman Island, Pahang, Peninsular Malaysia

Abstract

This study reports on the petrology and geochemistry of the plutonic and volcanic on southern part of the Tioman Island. Tioman lies about 50km east of Rompin district, Pahang. The island is dominated by plutonic and volcanic rocks with minor occurrences of metamorphic rock. The plutonic rocks consist of hornblende diorite and biotite granite. The hornblende diorite shows differences in mineralogy and geochemistry when compared to the main diorite body. The volcanics are mostly rhyolite and dacite with exception of andesite on other part of the island. Metamorphic rocks include the andalusite hornfels, quartz pyroxene hornfels, quartzite and amphibolite. Field relationships and published geochronological results indicates that the granite rock intruded both volcanic and diorite rocks during the Late Cretaceous (~80 Ma).The biotite granite post-dates the volcanic rocks by about 8.8Ma. Biotite granite shows slightly older age than the main Tioman diorite by about 1.5 Ma. The geochemistry of the igneous rocks from southern Tioman Island shows that they have a high-calc alkaline affinity which suggests that they are related to arc magmatism.