Grand Canyon 3-D Tour
River Mile 232 to Separation
Canyon (& Separation Rapid)
Grand Canyon Miles 232 to 240
View to the
northwest with river mile 232 at the lower edge. In the center
of the picture, Bridge Canyon enters from the left edge with
Gneiss Canyon immediately above it, while 236 Mile Canyon is
across the river on the right side. Near the top edge of the
picture, the Separation Canyon Fault cuts across the river and
forms twin canyons.
Until recently, Bridge Canyon Rapid (at the mouth
of Bridge Canyon) was the last rapid in the Grand Canyon as
the Lake Mead backup buried everything else downstream.
However, the current drought in the southwest has seriously
lowered the water level in Lake Mead, and if Gneiss Canyon
Rapid and 237 Mile Rapid have not reemerged yet, they will do
so in the near future. Even more interesting, it is possible
that Separation Rapid may resurface sometime in coming years.
The flat tops of the mesas are still the
Esplanade Sandstone, with the slope-forming Watahomigi
Formation just underneath. (Both are part of the Supai Group.)
The Redwall and generic limestone layers then form a sheer
cliff. Below these cliffs, the Bright Angel Shale forms a
slope just above the inner gorge. Then the Tapeats Sandstone
and Precambrian metamorphic rocks form a cliff down to the
View to the
northwest with 236 Mile Canyon in the right foreground. The
Separation Canyon Fault crosses in the middle of the picture
and erosion along the fault has produced twin canyons.
In Aug. 1869 three men from Powell's original
group decided to leave and hike out of the Grand Canyon via
Separation Canyon. They started up the north (right) canyon
and were never heard from again.
Of geologic interest there is a very small bump
just in front of the left end of the leftward continuation of
Separation Canyon. This is a remnant of a 19 million year old
lava flow, and indicates the flat Esplanade surface hasn't
changed much in 19 million years except where the Colorado
River has dug the canyon.
river miles 224 to 232
to river miles 240 to 248
the Index Page for the Grand Canyon Tour
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