Stratigraphy of Lithologic Units exposed around Banmaw Township

Abstract

The study area lies in Banmaw Townships, in the northern part of Myanmar and China to the east. This study mainly deals with the lithostratigraphy and petrography of the rock units exposed along the car road Banmaw-Lweje of Seinlon range, Banmaw-Dotphonyan and WilarthaTaung. The lithostratigraphic units exposed in the study area are granites, granitoid rocks, basic, ultrabasic and metamorphic rocks. Large bodies of granitic rocks and diorites are widely exposed along the car road from Momauk to Lweje. It is light gray to whitish grey coloured on fresh surface and dark gray or brownish coloured on weathered surface. Exfoliated or spheroidal weathered exposures are common. The granites are usually coarse-grained and mineralogically very similar throughout the entire region. Based on the radiometric dating, the age of biotite granite was Middle Miocene. The metamorphic rocks are generally trending nearly north-south and such as gneiss, protomylonite, calc-silicate rocks. Gneiss gives well-defined foliation and large scale banding. Foliated gneissose texture is peculiar in having alternates of dark color mafic minerals bands and light color quartzo-feldspathic bands due to metamorphic differentiation.