308 



STRUCTURAL GEOLOGY OF NORTH AMERICA 



* V" 



3,000 

 Sea level 



Fig. 20.5. A, section through Canadian Rockies at Mountain Park, Alberta, after MacKay, 

 1929. Section is north of limits of index map, Fig. 20.2. la, lb, and lc, Devonian; 2a, Banff 

 shale (Mississippian); 2b, Rundle limestone (Mississippian ?); 3, Rocky Mountain quartzite (Pennsyl- 

 vanian ?); 4, Spray River formation (Triassic); 5, Fernie shale (Jurassic); 6, Nikanassin shale 

 and sandstone; 7, Cadomin conglomerate; 8, Luscar shale and sandstone; 9, Mountain Park 

 sandstone, shale, and conglomerate (Lower Cretaceous); 10, Blackstone shale and sandstone 

 (Colorado). The thrust under Cheviot Mtn. cuts the Big Horn and Wapiabi formation of Colorado 

 age and the Brazean formation of Montana age, all younger than the Blackstone. 



C, section near Jumpingsound Creek, Alberta, after Hume, 1932. 1, Kootenay sandstone and 

 shale; 2, Blairmore sandstone and shale (1 and 2, Lower Cretaceous); 3, Lower Alberta shale; 



in most places — 7 degrees — and the fault surface has either been warped 

 or was uneven when formed. Two conspicuous klippen composed of 

 Reltian rocks on Mesozoic shales are known as Chief Mountain and 

 Divide Mountain, and near the headwaters of Ole Creek in the southern 

 part of the park there is a window of Mesozoic shales entirely surrounded 

 by Reltian rocks. South of Glacier National Park, the dip of the fault is 

 generally steeper, but beyond Fiord Creek, 75 miles south of the park, 

 the fault flattens out, and another window 3 miles long and half a mile 

 wide appears. Southeastward, still, it becomes steeper, and eventually it 



4, Cardium sandstone and conglomerate; 5, Upper Alberta shale (3, 4, and 5. Colorado); 



6, Belly River sandstone and shale; 7, Bearpaw shale; 8, Edmonton sandstone and shale (6 and 



7, Montana; 8, Montana ?); 9, Paskapoo sandstone and shale (late Paleocene). 



D, section through Turner Valley structure, Alberta, after Hume, 1931. 1, Paleozoic limestone; 

 2, Fernie shale (Jurassic); 3, Kootenay sandstone and shale; 4, Blairmore sandstone and shale 

 (3 and 4, Lower Cretaceous); 5, Lower Alberta shale; 6, Cardium sandstone (5 and 6, Colorado); 

 7. Upper Alberta shale (Colorado and Montana); 8, Belly River shale and sandstone (Montana); 

 9, Edmonton sandstone and shale (Montana ?); 10, Paskapoo sandstone and shale (late 

 Paleocene). 



is believed to join the Lombard thrust which has a dip of 40 degrees to 

 the west and northwest. 



Ross and Rezak (1959) conclude that the horizontal displacement of 

 the sheet was at least 15 miles, probably 35 miles, and possibly more. 

 They note the absence of erosional debris or an irregular land surface 

 over which some geologists had suggested the sheet rode, and postulate 

 the fault surface to be a shear. 



Whereas some thrusts and thrust complexes clearly exhibit character- 

 istics of gravity down-slope transport, it is difficult for the writer to con- 



