snoboy Posted February 4, 2003 Posted February 4, 2003 I've got this little flame going on over at www.telemarktips.com , in the 11th page of the "SME Time Bomb?" thread. I say the western border of the Canadian Rockies is the Rocky Mountain Trench, and this loser from Utah(?) is trying to tell me that no it isn't; that the Selkirks are part of the Rockies too. I am right or not? Come on geo 's... You can sign up instantly over there by the way... Quote
fern Posted February 4, 2003 Posted February 4, 2003 If European tourists are to be believed the Canadian Rockies extend all the way to the Pacific Ocean Quote
PONCHO&LEFTY Posted February 4, 2003 Posted February 4, 2003 I'm tired of people telling me the Canadian Mountains visible from Bellingham are in the Rockies. STOP! From "Washington Mountain Ranges" pg. 55 "Washington's top, (NE corner) anchored to the West by the North Cascades, in the East to the Kettles and Selkirks-the Rockies themselves." So maybe this helps. Quote
AlpineK Posted February 4, 2003 Posted February 4, 2003 Once in Jasper I walked into a a touron shop and thumbed through the postcards. I found this card that said, "Canada," and in smaller print it said, "Rocky Mountains." The picture on the postcard was a shot of the north side of Mt. Baker. Fuck those Utah fucks. The Rocky Mountains start east of the Rocky Mountain Trench. Quote
mattp Posted February 4, 2003 Posted February 4, 2003 On a Northwest Airlines flight, the pilot once announced that we were over the Canadian Rockies while we were still over the North Cascades, though we may have been on the Canadian side of the border at that point. Twenty minutes or a half hour later, we passed over the Bugaboos... That "loser" from Utah is right. It is ALL the rockies. Quote
Dru Posted February 5, 2003 Posted February 5, 2003 (edited) OK here is the straight dope from someone with a Geography M.Sc namely myself: Perkins is wrong, snoboy is right, concerning the CANADIAN mountains. According to Canadian terminology, the Rockies end at the Rocky Mountain trench. This fault zone demarcates a prominent boundary between thrust-faulted sedimentary rocks in the Rockies, and older exposed crystalline basement rocks in the Columbias. If Canadian geographic definition of the Rockies was applied to the American western mountains, the "Rockies" would end somewhere in Montana. The Colorado Rockies are geologically similar to the Selkirks, Purcells etc - except that instead of Rad Peaks they are 4000m scree piles. weest of the Columbia Trench, the Columbia Mountains are found including Selkirks, Purcells, Monashees, Valhallas, Cariboo Mts. etc. Then the Interior Plateau, then the Cascades (as far north as Spences' Bridge) then the Coast MOUNTAINS. The Coast RANGE is a bunch of shitty little hills in Oregon, California and Alaska. On Vancouver Island are found the Insular Mountains. Tourist guidebooks like to call the Columbia Mts "The Rockies" cause otherwise no one buys the picture book to take home to Tokyo or Dresden or wherever. Edited February 5, 2003 by Dru Quote
AlpineK Posted February 5, 2003 Posted February 5, 2003 I thought you didn't like the term Columbia Mountains. Quote
snoboy Posted February 5, 2003 Author Posted February 5, 2003 WooHoo! I knew it! Some others jumped on him to. He backed off, hasn't come back with a reply yet! Bye Bye! Quote
Dru Posted February 5, 2003 Posted February 5, 2003 I dont like the term Columbia Mountains, cause it reminds me of Kokanee beer commercials, but it is technically correct. Quote
AlpineK Posted February 5, 2003 Posted February 5, 2003 I thought it had something to do with Chic Scott. Quote
mattp Posted February 5, 2003 Posted February 5, 2003 Dru - Are you sure that the North Cascades are not part of the Canadian Rockies???? Damn. Quote
Dru Posted February 5, 2003 Posted February 5, 2003 Dru - Are you sure that the North Cascades are not part of the Canadian Rockies???? Damn. If they were, Barry Blanchard would have poached all your first ascents, perkins. Quote
bloody_flapper Posted February 5, 2003 Posted February 5, 2003 Long time lurker, first time poster. Dru- I thought I'd add to the topic because it seems to me that some of the geographic and geologic terminology have been mixed up. I am not a geographer, but a geologist. Did my masters in the North Cascades and a couple of summers of geology in the Selkirks many years ago. You are certainly right that the Canadian Rockies end at the Rocky Mountain trench. However, the Columbias are not similar to the U.S. Rockies. I believe the Canadian Rockies are separated because of their unique provenance in that they are thrusted continental shelf rocks. The U.S. Rockies are generally comprised of continental basement and sedimentary rocks exposed by the Laramide orogony. I believe that would include the Colorado Rockies, the Tetons, Wasatch, Uintas, etc. The Columbias are comprised of allocthonous terranes. That is, they were not originally part of North America but have been 'scraped" onto the continent as the Pacific Plate has subducted beneath the North American Plate. These accreted rocks make up most of Alaska, British Columbia, and extend into Washington, Oregon, Nevada, and California. I think it is still argued where the continental boundary is, but up by you, it is generally considered to be the Rocky Mountain trench. Geologically, the North Cascades are the southern extension of the Coast Plutonic Complex which extends north to Alaska. I guess the Coast Mountains (I always thought it was the Coast Range) is just a geographic distintion separated from the North Cascades by the Fraser River Valley. Feel free to add or correct if I missed something. Cheers ~bf Quote
snoboy Posted February 5, 2003 Author Posted February 5, 2003 I kinda left the guy alone. I thought he had learnt his lesson, and decided to eat a little pie. Now I see he has learnt something... Quote : "the Selkirks are not in the Canadian Rockies, but both ranges are within the Rocky Mountains." WTF? Go check the thread out, it's actually kind of interesting. (Link in my first post.) Quote
Dru Posted February 5, 2003 Posted February 5, 2003 Long time lurker, first time poster. Dru- I thought I'd add to the topic because it seems to me that some of the geographic and geologic terminology have been mixed up. I am not a geographer, but a geologist. Did my masters in the North Cascades and a couple of summers of geology in the Selkirks many years ago. You are certainly right that the Canadian Rockies end at the Rocky Mountain trench. However, the Columbias are not similar to the U.S. Rockies. I believe the Canadian Rockies are separated because of their unique provenance in that they are thrusted continental shelf rocks. The U.S. Rockies are generally comprised of continental basement and sedimentary rocks exposed by the Laramide orogony. I believe that would include the Colorado Rockies, the Tetons, Wasatch, Uintas, etc. The Columbias are comprised of allocthonous terranes. That is, they were not originally part of North America but have been 'scraped" onto the continent as the Pacific Plate has subducted beneath the North American Plate. These accreted rocks make up most of Alaska, British Columbia, and extend into Washington, Oregon, Nevada, and California. I think it is still argued where the continental boundary is, but up by you, it is generally considered to be the Rocky Mountain trench. Geologically, the North Cascades are the southern extension of the Coast Plutonic Complex which extends north to Alaska. I guess the Coast Mountains (I always thought it was the Coast Range) is just a geographic distintion separated from the North Cascades by the Fraser River Valley. Feel free to add or correct if I missed something. Cheers ~bf yeah bloody flapper, like i said, lots of the rocks in the columbia mountains, are also crystalline basement rocks. case in point, the Monashee Gneiss, has been dated thru U-Pb detrital zircons as over 2.1 Ga making it one of the oldest rox in canada outside the central core of the canadian shield. the rocky mountains, consist of the sedimentary cover of the columbias, which was thrust inland due to compression caused by the docking of Quesnellia. i cant remember when. then crustal Extension pulled western BC back west, and exposed the deep rock of the columbia core to the surface. this might correspond to the laramide orogeny. any ways, quesnellia (the interior plateau) and points west of the okanagan, are as you say, accreted micro terranes. NOW as to the various geographic names. this is the Canadian conventions. from smallest to largest: peak or mountain, range, Ranges, Mountains. thus you have for instance, Skihist Mountain is a summit of the Cantilever Range, which is one range of the Lillooet Ranges, which is one of several ranges which make up the Coast Mountains. in the columbia mts, peiople tend to refer to the individual ranges ie selkirks, puurcells. nobody but geologists ever refers to the pacific ranges, or the lillooet ranges, of the southern coast mountains. however they tend to be quite distinct. the lillooet ranges contain a bunch of microterranes geologically identical to the north cascdes, but separated from them by the fraser-yalakom fault (straight creek fault in usa) along which up to 600km of transverse motion has occurred since the mesozoic, i believe. this is why you find little chunks of the shuksan terrane up by gold bridge..... the in the pacific ranges only a few remnants of the older sed/metamorphic rox exist. the geology is dominated by the coast plutonic complex., the largest contiguous exposed granite body in the world, which extends from fraser river to near skagway AK. only one very recent pluton (25 Ma) sutures together the coast mts and cascades and it is found in the hunter creek-ruby creek area of the fraser canyon. nice rock too. anyways blah blah blah rocks Quote
catbirdseat Posted February 5, 2003 Posted February 5, 2003 It all reminds me of some of Fred Beckey's introductions in CAG only even more technical. I just love it when you guys use all those big words, like "allocthonous terranes". Is that cool, or what? Quote
Dru Posted February 5, 2003 Posted February 5, 2003 i was in the library once watching beckey copy out that geography stuff word for word from someone's thesis manuscript onto a mcdonalds napkin someone get him a text scanner! Quote
Mer Posted February 5, 2003 Posted February 5, 2003 Dr. Dru: I fear that contiguous exposure to detrital zircons has resulted in my developing terrible crustal extensions. Do you think this conditions can be medicated or will I need a laramide orogenectomy? I’d hate for this to develop into a plutonic complex. please advise. Quote
E-rock Posted February 6, 2003 Posted February 6, 2003 Dru, gotta correct you here again. Bloody flapper is correct in that the CO Rockies are quite different than the Columbies. Basement rx in the CO rockies were exposed during Laramide thick-skinned thrusting associated with shallowing of the subduction angle of the Farrallon slab. The CO rockies are quite unique in this respect. The crystalline rocks in the Columbias were exposed during rapid extension and exhumation of metamorphic core complexes which are distributed throughout the North American Cordillera. The Columbias are similar in that respect to The Raft Rivers of Utah, the Buckskins and Rawhides of Arizona and host of other core complexes. The Wasatch Mountains represent the foreland of a thin-skinned fold and thrust belt similar to the CanRockies, however these stuctures have since been overprinted by Basin and Range extension. The Columbia Mtns are what's called the hinterland of the the orgenic belt that formed the Can Rockies. The Colorado rockies are neither strictly an orogenic foreland or hinterland. To make things more complicated, Canadian geologists like to cite Quesnellian docking as the mechanism of Canadian foreland thrusting, whereas US geologist disagree, because all that was necessary here was ongoing subduction, not necessarily collision. Sorry it's late and I can't think I'll edit this for clarity some other time. However the Laramide Uplifts (Late K-early T crustal shortening) have nothing to do with exhumation in the Shuswap Metamorphic Core Complex (Eocene crustal extension). Quote
Billygoat Posted February 6, 2003 Posted February 6, 2003 If the Shu don't fit, swap it.... 100 posts. time to go to bed Quote
Dru Posted February 6, 2003 Posted February 6, 2003 e-rock say To make things more complicated, Canadian geologists like to cite Quesnellian docking as the mechanism of Canadian foreland thrusting, whereas US geologist disagree, because all that was necessary here was ongoing subduction, not necessarily collision. obviously another case where we are right, and you are wrong! altho' you're right i forgot how old the laramide orogeny was. i promise to respect american orogenous zones more in future Quote
David_Parker Posted February 7, 2003 Posted February 7, 2003 I'm glad you guys have your own friggin' language to talk about this stuff. Now we just need another catagory on CC. This makes "spray" look boring. Quote
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