Final Project
Notes taken 7-18-2014
1) Yoho Natural Bridge
This natural bridge is along the Kicking Horse River off of Hwy 1. The rock arch has developed in slate of the Chancellor Formation. Fine cleavage masks the bedding but it's possible to see through the various angles that the bridge lies in the core of a syncline.
Limy mud rock squeezed from mountain building and dissolved helped to create the formation along with river erosion.
The full structure has the appearance of a natural skateboard ramp.
~1 meter above water
water channel flow->
cleavage steeper than bedding which is right side up (93*)
Field Notebook Sketch |
2) Measurements at Outcrop Across way from Bridge
Across the road from the natural bridge in Yoho National Park, was an outcrop the class spent time at to further their strike and dip measuring skills.
By the observations made we came to the conclusions that the cleavage orientation was SW and the passive folded bedding was primarily NE.
These two planes share the same intersection and because one
layer is more stiff than its neighbor, buckle folding occurs as you can see in the picture below.
Bedding Measurement Examples:
285°/36°
273°/69°
273°/62°
280°/55°
280°/61°
Cleavage Measurement Examples:
049°/59°
099°/63°
098°/66°
110°/71°
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Photo Cred: Callan Bentley |
Field Notebook Sketch |
3) Outcrop Along Highway 1
Notebook Sketch |
Calcite, fine grained, phyllite, and mud rock. Pale wavy bands across the bedding and cleavage of Cambrian-aged Chancellor group slates were dykes brought on during the late Devonian. The rock is carbonatite from molten rock underneath the continental crust forcing its way into weak joints and cracks to produce a network of veins. In the igneous rock can be found carbonate(CO3) derived from the limestone and dolostone which is intruded (Gadd).
Dike (dark)= carbonotite - silica deprived
-color from iron (white/tan/yellow)
cleavage refraction found
-some quartz
cleavage refraction found
-some quartz
Cliffs of red brick colored limestone breccia stained from iron mark the location of the Red Wall Fault. The hematite coloring was more than likely sourced from pyrite ("fool's gold", FeS2) which occur in many rockies formations. The pyrite might have been concentrated by the flow of mineral-rich water along the fault zone. It was once thought to have been a normal fault which is why "Thrust" is not in the name. This fault is unique because the fault plane has been bent backward making it look like a normal fault. This fault is also a source of hot water used by the near by Radium Hot Springs. As you travel back from the cliff into the canyon the walls open, the corners tighten and the roads wind. If a glacier had flowed through here, it would have cut away the curves in the canyon says Gadd. This is evidence that the area is stream cut terrain.
*fault breccia - glued back together by minerals
-iron oxide (hemotite)
More on the tricky fault:
The flat-lying layers are deposited as usual, from the oldest upward to the youngest. A thrust fault breaks across the layers, bending them upward. Another thrust fault develops, bending the layers in the first thrust back, beyond the vertical (back-rotating them to the point of being overturned(Gadd)).
Recommended Readings:
Canadian Rockies Geology Road Tours by Ben Gadd