21 May 2012

Up on Sulphur Mountain

Posted by Callan Bentley

Here’s the view riding up (or down) Sulphur Mountain, Banff, on the gondola:

As you can probably tell from the cable lines’ misalignment, this was a composite (stitched) photo. Mt. Rundle is in the background.

If you turn to the left, you can see Tunnel Mountain, south of the town of Banff:

Tunnel Mountain is interesting on a couple of levels. To a glaciologist, it’s a roche moutonée — a profound valley glacier flowed over it from left to right (west to east) during the Pleistocene:

Actually, Tunnel Mountain is a structural, along strike, Mini-Me twin of the much larger Mt. Rundle, which you can see here as it looks from Banff town:

Mt. Rundle is the namesake of the Rundle limestone, a Mississippian limestone that is a major ridge-former in the Canadian Rockies. Here’s what Mt. Rundle looks like from the top of Sulphur Mountain:

The asymmetry of Mt. Rundle is a surefire signal that its strata dip towards the southeast (toward Sulphur Mountain). Each of these mountains is a thrust sheet, like Sun River Canyon further along strike to the south, in Montana.

Back in the gondola, here’s a look at the spot where Tunnel Mountain takes its leave from Mt. Rundle…

…The Bow River slices right on through! I guess you’d call that a water gap, of sorts.

Here’s a “terrain” Google Map view of the area:

Up on top of Sulphur Mountain, we found tilted limestone. The rock dips to the southeast, like the strata of Mt. Rundle:

Note the differential weathering.

I really liked the intersection of the planes of bedding and the planes of railing shadows here:

The view to the southwest at Sundance Peak…

…That’s what you call a U-shaped valley.

We turned our gaze to the northwest, where we gazed back at where we had been hiking earlier that same day:

Zooming into the middle of that image, you can see distinctive Mt. Louis (the tower at right):

Leaving Sulphur Mountain via gondola, and looking to the southeast, we saw a rainbow:

Looking forward to returning to this spot in July… a lovely spot.