Chapter 18 Geochemistry and geochronology of granitoid rocks in the Mawpalaw Taung area, Thanbyuzayat Township, southern Myanmar: their petrogenesis and tectonic setting

Abstract

Granitoid rocks in Myanmar occur in three north–south-trending linear belts (Khin Zaw 1990) (Fig. 18.1b) over a distance of more than 1500 km from Kachin State in the north through Mogok, Mandalay, Taungoo and Mon State to the Tanintharyi Region in the south. This chapter describes a suite of granitoid rocks exposed at the Mawpalaw Taung area, covering about 141.44 km2 in the Thanbyuzayat Township, Mon State, southern Myanmar (Fig. 18.1a), not described previously. The area is located within latitudes 15° 45′ N to 15° 53′ N and longitudes 97° 45′ E to 97° 51′ 30′′ E and lies about 80 km south of Mawlamyine. The aim of this chapter is to describe the petrology, geochemistry and geochronology of these granitoid rocks and their associated mineralization in the Mawpalaw Taung area and to discuss their petrogenesis and tectonic setting. Fig. 18.1. ( a ) Location map of the Mawpalaw Taung area, Thanbyuzayat Township, southern Myanmar and ( b ) the Granitoid Belt of Khin Zaw (1990). The Mawpalaw Taung area lies within the Shan–Tanintharyi Block (Maung Thein & Ba Than Haq 1969) in the northern Tanintharyi Hill Range, and forms a part of the Slate Belt of Mitchell et al. (2012). It also is a section of the Southeast Asian tin–tungsten belt, stretching from southern Yunnan in the north through eastern Myanmar, Thailand and the Malay Peninsula to the Indonesian Tin Islands (Maung Thein 1973; Mitchell 1977; Cobbing et al. 1992; Schwartz et al. 1995). The area lies within the Western Granite Province of Southeast Asia (Cobbing et al. 1992) (Fig. 18.1) and the Central Granitoid Belt of Myanmar (Khin Zaw 1990). The general structural trend of this part of the Slate Belt (Mitchell et al. 2012) is NNW–SSE aligned. The metasediments and igneous rocks lie between parallel …