Landforms of British Columbia 1976 - Department of Geography

sculptured by high-level cirque glaciers, Ice descending into the valleys and moving
outward from its source has modified the valley outlines and has, through differential
erosion, created the hanging-valley relationships so characteristic of glaciated
mountainous terrain. In many places glacially oversteepened mountain slopes are
so unstable. that erosion is proceeding rapidly, with production of huge talus piles
that ccwer much of the gentle lower slopes,
[References: North, F. K., and Hen&rson, G. G. L., “ Geology of Southern
Rocky Mountains of Canada,” ,4l&. .Soc. Pet. GeoZ., Guidebook No. 4, 1954;
Sorenson, M, K,, “Rocky Mountain Trench,” ,4l&. .%c. Pet. Gal., Guidebook
No. 5, 1955; Allan, J, A., “ Geology of Field Map-area,” Geol. Sw-v., Canada,
Man. 55, 1914; Warren, P, S,, “Banff Area,” Gal. Surv., Canada, Mem. 153,
1927; MacKay, B, R.> “ Geology of the National Parks uF Canada: Can. Geog.
Jaw., April, 1952; Baird, D. M., “ Yoho National Park,” Geol. Sure., Canado,
Misc. Rept. No. 4, 1962.1
[Photographs: B.C. 759:31; B.C. 766:44; B.C. 767:28, 32; B.C. 891:11,
73; B.C. 894:32; B.C. 896:46; B.C. 1204:90; B,.C, (0):465; R.C.A.F.
T3lL:l48,]
Hart Ranges
The ranges between Mount Sir Alexander and the Peace River constitute the
Hart Ranges, They are only moderately rugged and, except for Sentinel Peak
(8,200 feet) and Mount Drysdale (7,950 feet), do not exceed 7,500 feet in height
(see Plate XXXVIB). They contrast very sharply with the majestic mountain
groups to the south, and are considerably lower than ranges north of the Peace
River. The Hart Ranges constitute a central belt of lower elevation in the Rocky
Mountains that is the topographic equivalent of the Kitimat Ranges in the Coast
Mountains.
The Hart Ranges have a length of 180 miles between Mount Sir Alexander
and the Peace River and a width ranging between 18 and 40 miles. The ranges
are crossed at their narrowest part by the Hart Highway and the Pacific Great
Eastern Railway, by the Peace River to the north (see Plate XLIVA), and by the
little-known route through the Monkman Pass to the south. Their geology and
structure are imperfectly known except by a few oil exploration geologists.
Where crossed by the Hart Highway there is a perfectly apparent natural
division of the Hart Ranges at Azouzetta Lake, between the Murray and Solitude
Ranges on the east and the Misinchinka Ranges on the west. It is evident, more-
over, to all who are familiar with the southern mountains that the Hart Ranges
differ greatly from the Continental Ranges. The differences are primarily the
result of fundamental changes in the stratigraphy and structure of the rocks, and
of the differences in amount of the late Tertiary uplift and dissection.
The Murray Range has a width of 4 miles on the Hart Highway and rises to
6,686 feet above well-timbered lower slopes. The western face of the range is a
dip slope of about 40 degrees, and the northeast warp is fretted with cirques with
steepened headwalls and some. basins occupied by tarn lakes. The range on both
sides is bounded by southwesterly dipping thrust faults.
The Solitude Range is 3 miles wide. It is bounded by thrust faults and is
essentially composed of a block of rather complexly folded Upper Palaxoic
limestone having a dip slope facing southwest and a cirque-sculptured scarp slope
on the northeast.
These two ranges are topographically and structurally similar to the Front
Ranges of the Continental Ranges and occupy the same frontal position on the
western side of the Foothills. When more information is available about the eastern
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