Paunggyi Fm

Chindwin Basin, these conglomerates on account of their typical development near Paunggyi villages, about three miles south by east of Ngape town in the south west of the Minbu district, have been designated the Paunggyi conglomerate by Cotter. Although the Paunggyi Conglomerates form the base of Eocene with some grits and sandstones, these conglomerates are too inconsistent to be separated off from the Laungshe Shale Fm as a distinct Fm also the conglomerates can present at various horizons in the Laungshe Shale Fm. In Minbu-Salin Basin, Gangaw area. [Original Publication: Barber, A. J., Khin Zaw & Crow, M. J. (eds) 2017. Myanmar: Geology, Resources and Tectonics. Geological Society, London, Memoirs, 48, 219–260]

Synonym: Paunggyi Conglomerate. In the Pokku district, they are called the Shwelegyin Conglomerate Fm.

[Figure: Map showing location of sub-basins of the Central Myanmar Basin (after Myint Thein and M. Maung 2017)]

Conglomerate. The conglomeratic beds vary from thin grits to thick boulder beds and are in places associated with quartzitic sandstones. In the Pokku district, they are called the Shwelegyin Conglomerate Fm. Composed of blue-grey, yellow-brown, fairly hard, poorly sorted sandstones with quartz pebbles, interbedded with dark-grey, carbonaceous shales and pack–wackestones with a sediment thickness of 335 m (1100 ft). In Minbu-Salin Basin and Pyay Embayment, it is coarse-grained sandstone. The Fm is composed of sandstones, interbedded with gritty to conglomeratic beds and limestones. Algae-rich packstone and wackestone lenses are developed in the Gangaw area. Sandstones are light grey to yellowish-brown, fairly hard, bedded, fine- to coarse-grained, poorly sorted, micaceous and lithic, with thin carbonaceous laminations.

[Figure: Stratigraphic succession of the Chindwin Basin (after Than Htut, 2017)]

The conglomerates of the coeval Shwelegyin Fm contain Orthophragmina and small Nummulites, which indicate definitely Eocene in age in Chindwin Basin. Contains the foraminifera Lockhatia spp. And Kathina sp., the alga Distichoplax biserialis and Miscellanea in Minbu-Salin Basin and Pyay Embayment.

Deposited in nearshore and deltaic environments in Chindwin Basin. Deposited under shallow-marine to nearshore lagoonal conditions in Minbu-Salin Basin and Pyay Embayment.