Type Locality:

Type section at the headwaters of Pastel Creek (62°47'N, 125°15'30"W) on Delorme Range in the Root River map-area (95K), District of Mackenzie.

Distribution:

The Delorme is 990 m (3,250 ft) at the type section and is about 1,000 m (3,280 ft) throughout the Root River map-area (95K). It is mapped throughout the Mackenzie Mountains and is part of the Cordilleran Lower Paleozoic shelf sequence. In some places, in the northern part of the Mackenzie Mountains, rocks mapped as Delorme Formation are less than 30 m (98 ft) thick. The Delorme Formation has not been mapped in the subsurface of the Mackenzie Plain.

Locality Data:

Thickness(m): Typical 1000.

Lithology:

The type section consists mainly of light grey, thin- to medium-bedded, finely crystalline, slightly vuggy dolomite and silty medium-bedded dolomite. The basal part of the section is interbedded soft dark grey shales and clayey black argillaceous limestones and dolomites and the uppermost recessive part is dark grey thin-bedded limestone and dolomite. However, most of the mapped extent of the Delorme is better represented by the sequence of lithologies on the east flank of Whittaker Anticline. Here the lower part of the Delorme is interbedded dark grey shale and thin-bedded dolomitic siltstones that weather bright orange with some more massive medium grey dolomites and limestones. These beds are succeeded by orange weathering, dark grey silty and sandy limestone and some light grey thin bedded limestone. This orange colour is a useful mapping criterion for the Delorme.

Relationship:

The Delorme Formation conformably overlies the Whittaker Formation and underlies the Camsell Formation in the type area. In places where the Camsell is absent, the Delorme underlies either the Sombre or Arnica formations. Eastward, the Delorme Formation may be truncated by the basal detrital facies of the Bear Rock Formation. Westward, the Delorme passes to Road River shales of the Selwyn Basin. In the northern part of the Mackenzie Mountains across Twitya uplift, rocks that have been mapped as Delorme unconformably overlie a succession of formations as old as Helikian. Parts of the present Delorme may be renamed (Morrow and Cook, pers. comm., 1979).

Remark:

See Delorme Group

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.