Bulletin of the Geological Society of Malaysia, Volume 9, Nov. 1977, pp. 175 – 186
Department of Geology, Chulalongkorn University, Bangkok
Geological Survey Division, Department of Mineral Resources, Bangkok
Abstract: The Tak Batholith is located in Tak province and nearby areas in northern Thailand. The pluton covers an area of more than 4,000 square kilometers, and is believed to be a composite intrusion. Minimum age of the emplacement is Triassic. The large pluton is elongated north-south with small stocks scattered around its southern tip.
Petrographical and geochemical investigations reveal that the rocks can be classified into four main types namely; quartz diorite, granodiorite, quartz monzonite, and granite. Quartz diorite is found predominantly in the central cores; coarse-grained granodiorite forms the northern and western margins of the batholith; whereas quartz monzonite occupies the central-north and northwestern rims; and granite is scattered as small stocks in and around the southern rim or the main pluton. Andesitic, rhyolitic, and lamprophyric dikes are common in the area studied.
The batholith shows strong enrichment of Na2O + K2O in the A-F-M diagram.