Delorme Group

Unit Name: Delorme Group
Unit Type: Lithostratigraphic
Rank: Group
Status: Formal
Usage: Currently in use
Age Interval: Silurian - Devonian (443.7 - 359.2 ma)
Province/Territory: Northwest Territories

Originator: Williams, 1989; formally defined by Morrow, 1991

Distribution:

The study area examined by Morrow (1991) includes the Mount Eduni, Bonnet Plume, and Carcajou Canyon map areas. The Delorme Group is thin or absent over large areas of the northern Mackenzie Mountains. It is entirely absent from the region of the Morman Wells High. The Delorme Group strata increase in thickness westward and southward and reach their maximum thickness in the Camsell Sub-basin (Morrow, 1991).

Lithology:

Carbonates, evaporites and clastics (Williams, 1989). Argillaceous yellow-orange and grey peritidal and supratidal dolostones and evaporites that display considerable regional variations in the thickness and lithology (Morrow, 1991).

Relationship:

The Delorme Group includes all strata between the Mount Kindle (or Wittaker) Formation and the Bear Rock Formation or Group (Williams, 1989). According to Morrow (1991), the Delorme Group contains the Root River, Vera, Cadillac, Camsell and Tsetso formations.

History:

Morrow and Cook (1987) noted that the Delorme Formation of Douglas and Norris (1961) "resembles a sandwich with two more extensive facies enclosing two less extensive facies", and subdivided the parts of the Delorme Formation above the basal shale sequence into three new formations: the Root River, the Cadillac and the Vera. Morrow (1991) found the conept of the Delorme Formation of Douglas and Norris (1961) useful as it had been mapped extensively throughout the Mackenzie Mountains, and proposed that it be elevated to group rank.

References:

Douglas, R.J.W. and Norris, D.K., 1961. Camsell Bend and Root River map-areas, Northwest Territories; Geological Survey of Canada, Paper 61-13, 36 p.

Morrow, D.W. and Cook, D.G., 1987. The Prairie Creek embayment and lower Paleozoic strata of the southern Mackenzie Mountains; Geological Survey of Canada, Memoir 412, 195 p.

Morrow, D.W., 1991. The Silurian-Devonian Sequence in the Northern Part of the Mackenzie Shelf, Northwest Territories. Geologic Survey of Canada, Bulletin 413, 121 pages.

Williams, G.K., 1989. Tectonic Evolution of the Fort Norman Area, Mackenzie Corridor, N.W.T. Geological Survey of Canada, Open File 2045; 98 pages.

Source: GEOLOGICAL SURVEY OF CANADA
Contributor: G.E. McCune; P.H. Davenport
Entry Reviewed: No
Name Set: Lithostratigraphic Lexicon
LastChange: 18 Oct 2010