Regional Geology

1. Chaung Magyi Formation (Upper Precambrian) At the west and western part of Bawdwin area, Basal Sediment is Chaung Magyi Series (now termed the Chaung Magyi Group) of Precambrian age. It consists of shale, Slate, greywack and Phyllite and underlies the Pangyun rock of the mine area.
2. Taungpen Granite (Cambrian–Ordovician) Taungpeng Gratnite of Cambrian to Ordovician age is well exposed at the west and north-west of Bawdwin area. It comopsed light grey, medium grained rock consisting of quartz, orthoclase, microcline and biotite with minor plagioclase. The granite intrudes into the Chaung Magyi sediments.
3. Pengyun Formation (Cambrian) Pangyun Formation made up of Purple shale and thinly bedded, purple sandstone, dark reddish sandstone, interbedd with shaly horizone, Towards Tiger Camp, it become more feldspathic and gritty and coarse quartzites. It can be found in surrounding the Bawdwin Mine. Individual quart units are 5 to 100 cm thick; a shallow-water depositional environment is indicated by the common occurrence of ripple marks and cross-bedding.
4. Bawdwin Volcanic Formation (Cambrian) The Bawdwin Volcanic Formation includes volcaniclastic sedimentary rock and rhyolite and related porphyries. Volcaniclastic sedimentary rock is called Bawdwin tuff which consists of arkosic sandstone, volcanic greywacke clay and carbonates in which the original texture of the rock is completely destoryed. It is light grey to greenwish grey colour. Rhyolite and related porphyries are called Bawdwin rhyolite  and is grey to reddish brown colour. The reddish brown colour porphyry is named Nam La-porphyry and white to light colour porphyry is named Loi Mi-porphyry (Brinckman, Karisten Hinze,-1976, 1981).
5. Nyaung Kangyi Formation (Ordovician) Nyaung Kangyi Formation of Ordovician age is conformable with the underlying Pangyun Formation. It consists of brownish red of chocolat sandy  fossiliferous mudstone, shale and yellowish and reddish brown marls. Sandy zones occur locally. Panghsapye Graptolite Bed is exposed at the top of Naung Khangyi Formation. It consists of thin black carbonaceous graptolite-bearing shale. 
6. Panghsapye Formation (Silurian) Panghsapye Graptolite Bed is exposed at the top of Naung Khangyi Formation. It consists of thin black carbonaceous graptolite-bearing shale.
7. Nam Hsim Sandstone (Silurian) Nam Hsim Formation can be correlated stratigraphically Silurian age which is exposed to the east between Bawdwin and Namtu. Well exposer are found along rail line. The Nam Hsim Sandstones are very light grey to witish, medium grained, very hard, thick bedded, jointed and locally breciated.
8. Plateau Limestone Group (Upper Carboniferous to Triassic) Plateau Limestone of Upper Carbonaceous to Triassic age is well exposed around Namtu. It composed of Pure Limestone through Dolomitic Limestone  to purple dolomite and locally ripple marked quartzose sandstones and limestones. 
9. Namyan Bed (Jurassic)  Namyau Group is ovserved the area to the south of Namtu. Lithology is dark red to  purplish sandstone with occasional limestones at the base and clay in the upper part and is correlated Jurassic age.

References

1. The Australian Mineral Development Laboratories, Tim Hopwood  (AMDEL, 1985)
   Tne Mineral Resources of Burma (N.M Penzer,1922)
   
   Soe win U –Mineral deposists of Myanmar (Bawdwin, 2002)
   Khin Zaw, Peter Rice and Michale Roachi: Geological and Matallogenic Relations of Mineral deposists in Myanmar (Interim Report,1993)
   Geology of Burma (Bender, 1983)