Landforms of British Columbia 1976 - Department of Geography
Landforms of British Columbia 1976 - Department of Geography
Landforms of British Columbia 1976 - Department of Geography
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The amount <strong>of</strong> relief is governed by the elevations at which the rivers are<br />
flowing, and these in turn are controlled by various lake-levels, such as 1,379 feet<br />
at Lower Arrow Lake, 2,235 feet at Kinbasket Lake, 1,753 feet at Slocan Lake,<br />
2,400 feet at Trout Lake, and 1,765 feet rit Kootenay Lake.<br />
The ranges north <strong>of</strong> Trout Lake are extremely rugged and have high relief.<br />
The peaks are sharp and are separated by deeply incised glaciated valleys. There<br />
are few interconnecting ridges. The high peaks projected through the Pleistocene<br />
ice-sheet and still hold numerous icefields and glaciers which have sculptured the<br />
summits in typical fashion. The sedimentary and metamorphic rocks <strong>of</strong> the region<br />
have a northwesterly trend, which controls the direction <strong>of</strong> the ranges and has im-<br />
posed a trellis-like pattern upon the drainage.<br />
South <strong>of</strong> Trout Lake the area is largely underlain by intrusive rocks, which<br />
Cairnes remarks in the Slocan Mountains “ show the strong relief characteristic <strong>of</strong> a<br />
mountainous topography in a late adolescent stage <strong>of</strong> erosion. The areas <strong>of</strong><br />
Nelson granite and Kaslo series arc norma!ly more rugged and sharper in outline<br />
than those underlain by sediments <strong>of</strong> the Sloan series.“* The Sloan Ranges are<br />
characterized by long, uniformly steep, heavily timbered slopes rising through about<br />
5,000 feet to angular peaks and sharp narrow interconnecting ridges. Cirqw glaciers<br />
have sculptured the peaks, and high ridges and valley glaciers have facetted the spurs.<br />
South <strong>of</strong> Nelson the several ranges comprising the southern Selkirk Mountains<br />
do “ not show the rugged alpine topography <strong>of</strong> the Slocan, Lardeau, and n~ore north-<br />
erly ranges <strong>of</strong> the system The mountains <strong>of</strong> the southern Selkirks [see Plate XXIXBI<br />
are more subdued and rounded than those <strong>of</strong> the north with fewer rugged peaks and<br />
serrated ridges and without the youthful glacial forms due to higher uplift and more<br />
recent sculpture by mountain glaciers. In this portion <strong>of</strong> the Selkirks there are.<br />
practically no glaciers and the ranges form a transition belt <strong>of</strong> mountains connecting<br />
the high and rugged Canadian Selkirks with the low, subdued mountain ranges <strong>of</strong> the<br />
same system which border the <strong>Columbia</strong> lava plain in Washington state. . .<br />
Glacial forms, including cirques, a&es, trough-shaped valleys, truncated spurs,<br />
hanging valleys, roches moutonn&es, and valley terraces, are prominent topographic<br />
features in the landscape.“t<br />
[References: Wheeler, .J. O., “ Rogers Pass Map-area,” Geol, Surv., Canada,<br />
Paper 62.32; Little, H, W., “Nelson Map-area (West Half),” Ge01. SIUV., Canada,<br />
Man. 308, 1960; Gunning, H. C., “ Geology and Mineral Deposits <strong>of</strong> Big Bend<br />
Map-area,” Geol. Surv., Canada, Sum. Rept., 1928, Pt. A, pp. 136-193; Walker,<br />
.I. F., and Bancr<strong>of</strong>t, M. F., “ Lardeau Map-area,” Geol. Surv., Canada, Man. 161,<br />
1930; Cairnes, C!. E., “ Slocan Mining Camp,” Geol, Surv,, Canada, Man. 173,<br />
1934; Drysdale, C. W., “Ymir Mining Camp,” Geol. Surv., Canada, Man. 94,<br />
1917; Walker, J. F., “ Geology and Mineral Deposits <strong>of</strong> Saltno Map-area,” Geol.<br />
Swv., Canada, Mem, 172, 1934; Fyles, J. T., and Eastwood, G. E. P., “Geology<br />
<strong>of</strong> the Fergoson Area,” B.C. Dept. <strong>of</strong> Mines, Bull. No. 45, 1962.1<br />
[Photographs: B.C. 489:82, 107.1<br />
Purcell Mountains<br />
The Purcell Mountains occupy an elongate triangular area 190 miles long and<br />
50 miles in maximum width. The Purcell Mountains lie east <strong>of</strong> the Selkirk Mountains<br />
and are separated from them by the long through valley occupied by the Beaver<br />
River, Duncan River, Duncan Lake, and Kootenay Lake. On the east they adjoin<br />
the Rocky Mountain Trench.<br />
‘ caimes, c. E., Gd. .SrJ,“., ca”da, kkn In, 1934, p. 2*.<br />
+ mydale, c. w., Gd SU,“., can”da, Mml. 94, WI,, p, 7.<br />
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