The climb up to the crater is more of a scramble than a
hike and the way down is no easier. If you aren’t comfortable
climbing to the top see the alternate coordinates, but you’ll
miss the view of the crater and the surrounding basalt
flows.
The coordinates take you to the rim of one of the cinder cones that
about the same time as the source of the youngest lava flow in Snow
Valley, the Santa Clara flow. Vents located in a small side canyon
just south of the cinder cone are the source of the Santa Clara
flow. These cinder cones were likely active between 20,000 and
10,000 years ago and are currently considered extinct. However, the
literature points out that the conditions that caused the eruptions
in the entire region are still present today.
Cinder cones often are formed near the end of an
eruption. Any cones that are created early in the eruption are
likely to be destroyed by a later episode in the eruption.
Cinder cones are formed from cooled chunks of lava ejected
from a single central vent. Gas-filled lava is blown into the
air where it breaks apart into small fragments and quickly
cools creating cinders. These cinders are typically air filled
and relatively light for rocks of their size. The cinders
usually build up around the central vent to create a circular
or oval cone with a crater at the summit.
Image Source:
http://pubs.usgs.gov/gip/volc/types.html
As you climb the crater, or even at its base, you can see that
the cinder cone is made of many small pieces of air filled rock
with a few larger chunks. There is little cohesion and the pieces
easily slide down making the climb up and down treacherous.
The rocks of the cinder cone and the Santa Clara flow are a
basalt. Basalt is one of the four major categories of volcanic
rocks. It has the least amount of silica of the four types of
volcanic rocks. (Silica is a common compound found in the earth’s
crust). Basalt also tends to be the hottest and most fluid of the
volcanic rocks. See
http://volcanoes.usgs.gov/Products/Pglossary/VolRocks.html for a
further description and graphics regarding types of volcanic rocks.
The fluid characteristics of the basalt allows for the formation of
a variety of interesting flow features including lava tubes (link
to ecache) that can be found elsewhere in the park.
Logging requirements:
Send me a note with :
- The text "GCZ9C8 Cinder Cones of the Santa Clara Flow" on the
first line
- The number of people in your group.
- how well the cinders that make up the cone are stuck
together.
- How does this relate to the formation of the cone?
I will only respond if you have incomplete
logging requirements. Go ahead and log your cache
The above information was compiled from the
following sources:
- Higgins, Janice M. Geology of
Snow Canyon State Park, Utah in Geology of Utah’s Parks and
Monuments, 2003 Utah Geological Association Publication 28 (second
edition) D.A. Sprinkel, T.C. Chidsey, Jr. and P.B. Anderson,
editors
- USGS, Principal Types of Volcanoes,
http://pubs.usgs.gov/gip/volc/types.html
- USGS, Types of Igneous Rocks, Volcano Hazards
Program – Reducing volcanic risk,
http://volcanoes.usgs.gov/Products/Pglossary/VolRocks.html