Travel Reference
In-Depth Information
exquisite works of art. But where do the colors come from? What dynamic forces have meticu-
lously painted these stone sculptures so perfectly?
The answer, simply and unpoetically put, is rust. Most of the rocks at Zion and Bryce Canyon
are colored by iron, or hematite (iron oxide), either contained in the original stone or carried into
the rocks by groundwater. Although iron most often creates red and pink hues, frequently seen in
Zion's towering sandstone faces and Bryce Canyon's spectacular amphitheaters, it can also result
in blacks, browns, yellows, and even greens. Sometimes the iron seeps into the rock, coloring it
through, but it can also stain just the surface, often in vertical streaks.
Rocks are also colored by the bacteria that live on their surfaces. These bacteria ingest dust and
expel iron, manganese, and other minerals, which then stick to the rock, producing a shiny black,
brown, or reddish surface called desert varnish. Last, but certainly not least, is the work of water,
which deposits salt as it evaporates, creating white streaks.
The most important of Zion's nine rock layers—at least in the creation of those
imposing rock formations—is
Navajosandstone,
which is the thickest rock layer
in the park, at up to 2,200 feet. The sandstone layer was created some 200 million
years ago, during the Jurassic period, when most of North America was hot and
dry. Movements in the earth's crust enabled a shallow sea to form over windblown
sand dunes. Then minerals, including lime from the shells of sea creatures, even-
tually glued sand particles together to form sandstone. Later, crust movements
caused the land to uplift, draining away the sea, but leaving rivers that gradually
carved the relatively soft sandstone into the spectacular shapes we see today.
By comparison, Bryce Canyon is a mere babe. Its rocks were formed some 64 mil-
lion years ago, created from sediments that were left behind when ancient lakes
and rivers dried up. As at neighboring Zion, these rock layers were then uplifted
and exposed to the ravages of nature. Much of Bryce Canyon's rock is
limestone,
relatively soft and crumbly, which was easily eroded into the park's numerous in-
tricate hoodoos. The processes that created the rock formation in both parks con-
tinue today. Even to the naked eye, it's possible to see the changes that weathering
has produced on Bryce Canyon's famous
QueenVictoria
hoodoo over the past 25
years.
The Flora
Great variations in elevation and the availability of water have resulted in numer-
ous microclimates throughout these two parks. In one section, you can see desert
grasses, sagebrush, and a few cacti; while in another, not far away, there might be
deep green woods where maidenhair ferns and cottonwood trees thrive. Zion Na-
