Sassenach Formation

The Sassenach Formation is a stratigraphic unit of Late Devonian (early Famennian) age. It is present on the western edge of the Western Canada Sedimentary Basin in the Rocky Mountains and foothills of Alberta. It consists primarily of mudstone, siltstone, and silty carbonate rocks, and was named for Mount Sassenach in Jasper National Park by D. J. McLaren and E. W. Mountjoy in 1962.^[1][2]

Sassenach Formation
Stratigraphic range: early Famennian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Underlies	Palliser Formation
Overlies	Mount Hawk Formation, Southesk Formation
Thickness	Up to about 245 metres (800 ft)[1]
Lithology
Primary	Mudstone, siltstone
Other	Limestone, dolomite
Location
Coordinates	53°10′00″N 118°14′00″W
Region	Alberta
Country	Canada
Type section
Named for	Mount Sassenach
Named by	D.J. McLaren and E.W. Mountjoy, 1962.[2]

The Sassenach Formation was deposited near the beginning of the Fammenian stage of the Devonian, following the Frasnian–Fammenian extinction event.^[3][4] It includes fossil conodonts.^[5]

Lithology and thickness

The Sassenach Formation was deposited below wave base in an off-reef marine setting.^[3] It consists of silty to sandy mudstone and siltstone, with argillaceous to silty and sandy limestone and dolomite. It has a maximum thickness of about 245 metres (800 ft).^[1]

Distribution and relationship to other units

The Sassenach Formation is present in the Rocky Mountains and foothills of Alberta, extending from northern Jasper National Park to the North Saskatchewan River, and it has also been tentatively recognized in some areas farther south. It overlies the Southesk Formation or the Mount Hawk Formation, depending on the location. It is overlain by the Palliser Formation, and is laterally equivalent to the upper beds of the Alexo Formation.^[1][6]