Bulletin of the Geological Society of Malaysia, Volume 17, Dec.1984, pp. 1 – 7
Dept. of Geology, University of Malaya, Kuala Lumpur, Malaysia
Abstract: Sg. Ara granite occupies the major part of the southern half of the Penang Island and comprises several textural varieties. The rocks are peraluminous (S-type), and are characterized by the presence of primary muscovite and occasional andalusite. Plagioclase is identified to be the liquidus phase. The stability of andalusite and muscovite, and the implication of liquidus plagioclase are considered with reference to an appropriate granite phase diagram to evaluate the P-T-XH2O conditions. Sg. Ara granite has probably crystallized under 3-4 Kb pressure (10-15 km) in the temperature range of 680°-780°C, with initial melt water content less than about 7 wt.%.