Lokepyin Fm
Type Locality and Naming
Shan North Plateau, Shan mid-Plateau (Pyin Oo Lwin), Shan South Plateau, area between Mandalay and Pyin Oo Lwin. In Shan State North the unit is widely distributed in Kyaukmoe, 3 km east of Kainggyi, NE of Sedawgyi in the Mandalay region, near Bok Taung west of Si-baing, Saga Taung Range, Sedawlay Valley, east of Panzon Chaung, Sin-hnin Chaung, west of Sakangyi village, Dattaw Valley, west of Anisakan and east of Kunlein (Taung means ‘hill’, and Chaung means ‘stream’ in the Myanmar language). The basal Ordovician rock unit in the area between Mandalay and Pyin Oo Lwin, termed the Lower Ordovician Limestone by La Touche (1913), is now recognized as being part of the Lower Naungkangyi Group. Following discussion by members of the Myanmar Geosciences Society (MGS), it was agreed that this unit in Shan State North should be included within the Lokepyin Fm, originally described from Shan State South (Myint Lwin Thein 1973), since it occurs in the same stratigraphical position (although it has a different lithology in places); it is therefore not necessary to give the more northerly outcrops a new stratigraphical name. [Original Publication: Barber, A. J., Khin Zaw & Crow, M. J. (eds) 2017. Myanmar: Geology, Resources and Tectonics. Geological Society, London, Memoirs, 48, 317-342]
Lithology and Thickness
Siliceous limestone. In the east of the Mandalay and Sedaw areas, it consists mainly of well-bedded blue limestone with thin silt partings, in contrast to the typical yellowish-brown siltstone cropping out east of Kunlein village. The unit is 912 m thick in the area east of Sedawgyi. In Shan Mid Plateau, it is Siliceous limestone. In Shan South Plateau, it is Siltstone.
Relationships and Distribution
Lower contact
Conformable with Bawdwin Volcanic Fm in Shan North Plateau, Conformable with Taunggyun Sandstone Fm in Shan mid-Plateau (Pyin Oo Lwin), Conformable with Myetye Fm in Shan South Plateau.
Upper contact
Regional extent
This Fm is developed in Shan North, Mid, South Plateaus. Can probably be correlated with the upper part of the Machingchang Fm of Malaysia (Cocks et al. 2005; Lee 2009) and the Tarutao Gr of Thailand (Wongwanich et al. 2002; Ridd 2011).
GeoJSON
Fossils
The small brachiopods Nanorthis spp. and fragments of the trilobite Aulacoparina sp. Were recovered from the limestone outcrops east of Kainggyi.
Age
Depositional setting
Shallow-marine environment in Shan North Plateau and Shan mid-Plateau (Pyin Oo Lwin), In Shan South Plateau, Win Naing (1991) suggested that the Lokepyin Fm might have been deposited in a shallow-marine, open-shelf environment.
Additional Information