View to the west-southwest
with Fern Glen Canyon in the right foreground and the Mohawk-Stairway
(also called Stairway-Willow Springs) Fault cutting across the center
of the picture. Erosion along the fault has generated twin canyons with
Mohawk Canyon to the left (south) and Stairway Canyon to the right. In
the distance, the Cove Canyon complex has cut into the North Rim with
Big Point near the center of the picture and Toroweap Point near the
upper edge.
The Redwall/Muav Limestone sequence still forms a massive
cliff next to the river, but the character of the inner gorge begins to
change as the river approaches the Toroweap Fault (extreme top edge).
The strata in this area begin to tilt upward toward the west, and as a
result the Bright Angel Shale resurfaces again just west of Fern Glen
Canyon. The Mohawk-Stairway Fault accentuates this trend as strata west
of this fault have been uplifted another 50 to 100 feet. The Bright
Angel Shale in this section of the Grand Canyon contains relatively
more sandstone than in areas further east, thus its slope-forming
tendency is not quite as pronounced.
View to the west-southwest
with Mohawk and Stairway Canyons in the foreground. The Cove Canyon
Complex joins the Colorado River near the center of the picture with
Toroweap Point (North Rim) just above it. In the distance the small
conical bump near the edge of the inner gorge is Vulcans Throne.
If you look closely just beyond the junction of Cove
Canyon and the Colorado you can see the effects of Red Slide where part
of the inner gorge has broken off and is slowly slumping down toward
the river. The erosion process in the canyon is accomplished by the
river cutting downward in its narrow path while everything else slips
down the sides. The "down the sides" can be a sudden rock fall, debris
flow, or slower slump, creep, etc. Once the material gets down to the
river, the river grinds it up and carries it downstream. Eventually,
the sand and silt are dropped in the river's delta, and a new
sedimentary layer is deposited as part of some future geologic
formation.
Return to river
miles 160 to 168
Continue to river
miles 176 to 184
Return to the
Index Page for the Grand Canyon Tour
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