Geology of the rock units exposed along the Mongla-Kengtung-Tarchileik road section, Eastern Shan State, Myanmar

Abstract

The study area lies in Kyaington and Tarchileik Townships, in the easternmost part of the Shan State. This study mainly deals with the lithostratigraphy and petrography of the rock units exposed along the Kengtung-Tarchileik-Mongla car road. The lithostratigraphic units exposed in the study area are clastic sedimentary rocks, granitoid rocks and metamorphic rocks. The distinctive sedimentary rock units are Loi Mwe red sandstones. They are pinkish to reddish, medium-grained ferruginous sandstone and quartz arenite. These red sandstones are unconformably overlained by the yellowish brown sandstone. According to the tectonostratigraphic study of the northwestern Thailand and southwestern China, the study area falls in the Chainging Belt. These sandstone beds can be regarded as the Jurassic-Cretaceous age and can be correlated with the Kalaw Red Bed. Large bodies of granitic rocks exposed in the study area might belong to the so- called Eastern Granitoid Belt of Myanmar. These igneous rocks are intruded into the sedimentary sequences. The granites are usually coarse-grained and mineralogically very similar throughout the entire region. They are two-mica granites containing abundant orthoclase (± microcline), plagioclase, biotite, muscovite and minor hornblende. Accessory minerals are rarely present. The age of these granites as determined by U/Pb dating method of Laser ICPMS yields 216 ± 6 and 224 ± 4 m.y. Low-grade meta-sedimentary rocks such as chlorite schist, phyllite, slate and metagreywacke are sporadically exposed and are found to be intruded by granites.

AAPG Datapages/Search and Discovery Article #90336 ©2018 AAPG Asia Pacific Region, The 4th AAPG/EAGE/MGS Myanmar Oil and Gas Conference, Myanmar: A Global Oil and Gas Hotspot: Unleashing the Petroleum Systems Potential, Yangon, Myanmar, November 13-15, 2018