Widening Canyon
This bend in the river marks a change in Zion Canyon scenery.
From here downstream the canyon is growing wider.
A key factor is the different type of rock. In the canyon wall just
above the river you can see the juncture where a darker mudstone
layer emerges. As the river undercuts this looser mudstone, the hard
santstone slabs above topple and wash downstream and the canyon
wall recedes several feet. Look for scars in the cliffs where slabs have
peeled away. Sometimes the attrition is gradual, but six river-miles
downstream the Sentinel Slide is a large-scale example of a suddenly
wider canyon.
Below the towering, erosion-resistant
walls of Navajo Sandstone lies a
weak formation of mudstones
and siltstones called the Kayenta
formation. Once the Virgin River
begins to carve into the weaker
Kayenta layer, erosion accelerates.
The sturdy walls of Navajo Sandstone
are undermined, and slabs fall into the
river, widening the canyon.
During high water or after a heavy
rain, you can hear the heavy cobbles
clattering in the current. The river
becomes a giant conveyor belt of gritty
abrasives carving out the canyon
