Isachsen Formation
Stratigraphic range: Aptian ~120–112 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Sub-units	Walker Island member
Overlies	Christopher Formation
Location
Coordinates	76°06′N 109°00′W / 76.1°N 109.0°W / 76.1; -109.0
Approximate paleocoordinates	71°30′N 20°30′W / 71.5°N 20.5°W / 71.5; -20.5
Region	Nunavut
Country	Canada
Isachsen Formation (Canada) Show map of Canada Isachsen Formation (Nunavut) Show map of Nunavut

The Isachsen Formation is a geologic formation in Nunavut. It preserves fossils of Polycotylidae indet., dating back to the Aptian stage of the Cretaceous period.

• List of fossiliferous stratigraphic units in Nunavut

• M. J. Vavrek, B. C. Wilhelm, E. E. Maxwell and H. C. E. Larsson. 2014. Arctic plesiosaurs from the Lower Cretaceous of Melville Island, Nunavut, Canada. Cretaceous Research 50:273-281

• Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.