Saturday, January 16, 2010

More Muncho

I'm planning to clear out a few draft posts from last year, and also to hopefully finish up some mini-series. I'm starting by taking a leap back to the dark ages of 2009 - February, that is. I had nearly completed a series I started about the northern Canadian Rockies, centered around Folded Mountain and Muncho Lake. I'm going back there again, this time to a location on the Alcan Highway about 7 miles or 11 km south of the south end of Muncho Lake: the pullout at Mile 426/km 686, Alcan mileage (current mileage). I think this is the "Sawteeth" pullout, which has a sign that may or may not explain the geology of the Sentinel Mountains. I can't actually follow the explanation, so I won't show you the sign! (I mean, it doesn't make any sense to me.)

This oblique southeasterly view of the Sentinel Mountains from Google Earth shows the general area from a little higher than roadside level; that's the Alcan, AKA Highway 97. The topography of the same area, looking straight down and with the north arrow cocked to the right, can be seen here in The Atlas of Canada.
The picture I took looks like this; it corresponds with the two central peaks from the Google Earth image, with just a little of the pyramidal-shaped range-front hill on the far left.
Drawing on a composite set of photos, I came up with this pen-and-ink interpretation, which shows the general flat-lying nature of the sedimentary horizons away from the range front and to the east. The beds are then tilted into a dip slope right along the range front, forming a set of triangular-shaped facets, which I described more completely earlier. If you look carefully at the photo and the sketch, you'll see that they match up imperfectly - the sketch makes the farther hill appear a little larger than life. It is a cartoon.

The Folded Mountain and Muncho Lake Series:

You'll find references, in-post links, more photos and images, and more about the Alcan and general geology in the previous posts.

6 comments:

Ron Schott said...

Thanks for this whole series, Silver Fox. Muncho Lake/Folded Mountain is growing ever higher on my personal "Lifetime List" of sights to see. I've already picked up Ben Gadd's Canadian Rockies Geology Road Tours - do you have any other suggestions for field guides to the region?

Silver Fox said...

Thanks, Ron. I don't really have any field guide suggestions. Thanks for yours! I'll keep it in mind for the next time I drive up there. It would be nice to know of geological guides for the rest of the route: B.C. and the Yukon.

Maybe Howard will have some suggestions.

Anonymous said...

I'm sorry to say I've never been to the Muncho Lake area--farthest north on the Alcan Hwy. I've been is Fort Nelson and I drove there from Ft. St. John at night, in the winter: so I didn't see much of it even then. Thanks for the "teaser".

Ron: I haven't seen Ben Gadd's Road Tours book (I've been meaning to buy it), but I seriously doubt that he covers the Muncho Lake region; it's pretty far off the beaten track, even for him. Other field guides to the better-travelled parts of the Canadian Rockies (Banff/Jasper and southward), and in a more technical vein, are available from the Canadian Society of Petroleum Geologists (CSPG), here: http://cspg.org/publications/store/field-guides.cfm
Some of these are getting a bit long in the tooth, but obviously the rocks haven't changed much.

As for the area of northern BC you're interested in, hmmm...the Geological Survey of Canada likely has Memoirs, Bulletins, Papers, and maps of the area, though many are likely to be out of print and only available in libraries. You might also try the Geological Association of Canada's bookstore at www.gac.ca

Cheers,
--Howard

Ron Schott said...

Hi Howard,

Thanks for the suggestions.

By the way, Ben Gadd's Canadian Rockies Geology Road Tours does get up to Folded Mountain and Muncho Lake - pages 524-537 in my first printing.

Anonymous said...

Ron:

"By the way, Ben Gadd's [book] does get up to Folded Mountain and Muncho Lake - pages 524-537 in my first printing."

Huh! That's pretty impressive--a surprise to me. I figured he had more than enough cool rocks to deal with down here in the "more civilized" areas (Muncho would be a good 2 or 3 days of hard driving from Calgary). Guess I'd definitely better grab a copy. Ben can thank you for selling another book!

Cheers,
--Howard

Silver Fox said...

Howard, thanks for the additional resources. And I'm going to buy Ben Gadd's book, too.