Landforms of British Columbia 1976 - Department of Geography

mostly in the Babine Range. The rock structures are extremely complex, the major
folds averaging about 4 per mile with many overturned and recumbent outlines.
Only in parts of the Groundhog Range, upper Skeena Valley, and Eaglenest Range
do broad open folds predominate. Structures in the easily eroded argillite are more
complex than in the resistant peak-forming greywacke. Typically the valleys and
saddles in the Skeena Mountains are characterized by tight complex folding, whereas
the broader massifs are commonly gently contorted or in places flat lying, an indica-
tion perhaps that major longitudinal faults, to which folding may be related, lie along
the valleys. Most of the fold axes are nearly horizontal or plunge gently northwest. *
The mountains are drained by the Stikine, Nass, and Skeena Rivers and their
tributaries, and are divided into ranges by prominent northwesterly trending valleys
whose size and rectilinear pattern are characteristic of the region. The valley bottoms
lie between 2,500 and 4,000 feet elevation, and are generally wide and drift-filled.
Peaks range for the most part between 6,000 and 7,000 feet, the highest being Nation
Peak (7,741 feet) in the Eaglenest Range, Oweegee Peak (7,540 feet) in the Owee-
gee Range, Melanistic Peak (7,710 feet) in the Tatlatui Range, Shelagyote Peak
(8,090 feet) and Motase Peak (7,910 feet) in the Sicintine Range, Kisgegas Peak
(7,700 feet) in the Atna Range, and Netalzul Mountain (7,645 feet) in the Babine
Range.
The peaks and high ridges present a serrate and jagged profile which has been
developed by intense alpine glaciation, through the production of cirques on their
northern and eastern sides. Remnant glaciers still remain along the crests of high
ranges, the greatest amount of ice being in the Atna and Sicintine Ranges, the two
highest. The valley proliles have been modified by valley glaciers, tarns and hanging
valleys abound, and the mountains everywhere show the erosional effects of cirque
and valley glaciers.
On the north the Skeena Mountains pass by transition into the Spatsizi Plateau.
In this zone, particularly on the northern limits of the Klappan and Eaglenest Ranges,
gently sloping areas of upland are remnants of the dissection of the late Tertiary
erosion surface (see Plate XmB).
Some flat and gently sloping upland areas in the northern Klappan Range are
underlain by Tertiary lava flows, which spread eastward from vents near Edziza Peak.
On the south, where the mountains adjoin the Nechako Plateau, the Babine,
Atna, Sicintine, and Bait Ranges, with their 6,500-foot and higher peaks, present a
front which rises abruptly above the plateau level, which is at 4,000 to 4,500 feet.
The boundary is sharp and is drawn along the generalized 5,000-foot contour.
The Skeena Mountains were almost entirely covered by the Pleistocene ice-
sheet, which rounded the ridges and summits below 6,000 feet. The most striking
glacial effects within the mountains are the result of cirque and valley glaciation
during the final recession of the Cordilleran ice-sheet. A legacy of Pleistocene ice
occupation is the derangement of drainage from previously established lines. The
zigzag course of the Skeena River downstream from Kuldo, in which the river cuts
across the northern top of the Babine Range in three ditIerent places, evidently was
determined by the presence of ice in adjoining valleys. The present drainage of
Babine Lake (2,332 feet) northward into the Skeena River below Kisgegas rather
than through the oId portage route across to Stuart Lake (2,230 feet) must be the
result of ice or morainal damming.
[References: “ Stikine River Area,” Geol. Surv., Canada, Map 9-1957; Buck-
ham, A. F., and Latour, B. A., “ The Groundhog Coalfield,” Geol. Surv., Canada,
Bull. No. 16, 1950.1
[Photographs: B.C. 507:53; B.C. 508:115; B.C. 522:101; B.C. 534:58,82,
94; B.C. 535:51,118; B.C. 538:4,56,95; B.C. 541:82.]
* Gad. Surv,, Canada, Map 9.1957, marginal note.
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