Unit Name: Cass Fjord Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Middle Cambrian - Early Ordovician (513 - 471.8 ma)
Age Justification: Lingulella was described (Koch, 1929a, b; Poulsen, 1927) as the most common fossils; an Early Ordovician age has generally been assigned on the basis of the presence of Hystricurus in the upper part of the formation. At least half of the unit, however, is referrable to the Middle and Late Cambrian from fossils of Dresbachian, Franconian, and Trempeleauian ages (Henriksen and Peel, 1976; Dawes, 1976a). Kurtz (1977) identified "Fauna B" conodont species in the upper 50 m of the Cass Fiord in southern Washington Land.
Province/Territory: Nunavut; Greenland
Originator: Poulsen, 1927.
Type Locality:
Cass Fjord, Washington Land, Northwest Greenland.
Distribution:
At least 400 m estimated by Koch in type area; 470 m indicated by Henriksen and Peel (1976) in type area; 490 m measured by Christie (1967) at Bache Peninsula, Ellesmere Island.
Locality Data:
Thickness(m): Typical 470.
Lithology:
Recessive, thin-bedded limestone, dolomitic limestone, and intraformational conglomerate; shaly, algal, and gypsiferous beds are present, the latter especially in the upper half of the section.
Relationship:
Conformably overlies the Middle Cambrian Telt Bugt Formation in the type area (Henriksen and Peel, 1976); conformably overlain by the Cape Clay Formation. On Bache Peninsula, conformably and abruptly overlies Middle Cambrian Cape Wood Formation (Christie, 1967). The name Cass Fjord Formation is restricted in Greenland to strata in Washington and Inglefield Lands (Peel and Cowie, 1979)
History:
The name was first published by Poulsen (1927), although brief lithological descriptions of the strata were given by Koch between 1923 and 1925. The formation had been surveyed and collected by Koch during the Jubilaeumsekspedition of 1920-23. Koch (1929a) later provided a full description under the name Cass Fjord Formation. The name was introduced to Canada (at Bache Peninsula, Ellesmere Island) by Troelsen (1950).
Other Citations:
Koch, 1929b.
References:
Christie, R.L., 1967. Bache Peninsula, Ellesmere Island, Arctic Archipelago: Geological Survey of Canada, Memoir 347, 63 p.
Dawes, P.R., 1976a. Precambrian to Tertiary of northern Greenland pp. 249-303: in Escher, A. and Watt, W.S. (eds.), Geology of Greenland, Geological Survey of Greenland, Copenhagen, 603 p.
Henriksen, N. and Peel, J.S., 1976. Cambrian-Early Ordovician stratigraphy in southwestern Wash-ington Land, western North Greenland: Gronlands Geologiske Undersogelse, Rapport Nr. 80, pp. 17-23.
Koch, L., 1929a. The geology of the south coast of Washington Land: Meddelelser om Gronland, Bd. 73, Afd. I, Nr. I, 39 p.
Koch, L., 1929b. Stratigraphy of Greenland: Meddelelser om Gronland, Bd. 73, Afd. I, Nr. 2.
Kurtz, V.E., 1977. Trans-cratonic correlation of early Ordovician conodont faunas B and C between Northwest Greenland and western United States: Geological Society of America, Abstracts, vol. 9, no. 5, p. 618.
Peel, J.S. and Cowie, J.W., 1979. New names for Ordovician formations in Greenland: Gronlands Geologiske Undersogelse, Rapport Nr. 91, pp. 117-124.
Poulsen, C., 1927. The Cambrian, Ozarkian and Canadian faunas of Northwest Greenland: Meddelelser om Gronland, vol. 70, no. 2, pp. 233-343.
Troelsen, J.C., 1950. Contributions to the geology of Northwest Greenland, Ellesmere Island, and Axel Heiberg Island: Meddelelser om Gronland, vol. 149, no. 7.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 1, Arctic Archigelage (District of Franklin); R.L. Christie, A.F. Embry, G.A. Van Dyck (editor)
Contributor: R.L. Christie
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 15 Sep 2009