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OUTLINE 64: ANSWERS
1. What type of geological structures are represented
by the parallel linear ridges and valleys of the
northern Rockies? THRUST FAULTED BLOCKS
2.
Make a sketch of the geological relationships on
Yamnuska mountain, near Calgary.
West
YAMNUSKA MOUNTAIN
EAST
CAMBRIAN LIMESTONE
FLAT
THRUST FAULT
RAMP
3.
CRETACEOUS SHALE
What is the direction of dip of the thrust faults on the
eastern flanks of the Rockies? TO THE WEST
OUTLINE 64: ANSWERS (cont.)
4. What was the direction of movement of the thrust faulted
blocks? TO THE EAST
5. What was the ultimate cause of crustal compression?
PLATE TECTONICS – SUBDUCTION
6. What was the original width of the mountain belt calculated
to before compression? 300 KM
7. What is the present width of the mountain belt?
140 KM
8. What is the rate (mm/year) at which the crust has been
compressed?
160 KM IN 160 MILLION YEARS
= 160 x 103 x 103 mm/ 160 x 106 yrs = 1 mm/yr