Nahanni Formation
Stratigraphic range: Givetian PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Underlies	Fort Simpson Formation Horn River Formation
Overlies	Headless Formation
Thickness	up to 137 metres (450 ft)[1]
Lithology
Primary	Limestone
Location
Coordinates	61°03′0″N 123°37′0″W / 61.05000°N 123.61667°W / 61.05000; -123.61667 (Nahanni Formation)
Region	WCSB
Country	Canada
Type section
Named for	Nahanni Butte
Named by	C.O. Hage
Year defined	1945

The Nahanni Formation is a stratigraphical unit of Givetian age in the Western Canadian Sedimentary Basin.

It takes the name from Nahanni Butte, a prominent ridge at the confluence of the South Nahanni River and Liard River, and was first described in outcrop on the south face of the mountain by C.O. Hage in 1945.^[2]

The Nahanni Formation is composed of dolomitic limestone. ^[1]

gas is produced from the Nahanni Formation in the Mackenzie River Valley.

The Nahanni Formation contains paleofauna composed of corals, brachiopods and trilobites.

The Nahanni Formation reaches a maximum thickness of 137 metres (450 ft) at Nahanni Butte, and has typical thickness of 60 metres (200 ft). It occurs from the Franklin Mountains in the north to north-eastern British Columbia in the south.^[1]

The Nahanni Formation is conformably overlain by the Fort Simpson Formation in the west and by the Horn River Formation in the east. It overlays the Headless Formation diachronically and transitionally, with younger deposits occurring in the west.^[1]

It is equivalent to the upper part of the Hume Formation in the Mackenzie River area, as well as the Lonely Bay Formation, Pine Point Formation and Little Buffalo Formation in the Great Slave Lake area. In northern Alberta it corresponds to the Keg River Formation.