Lava
Point is a basalt flow from one of the cinder cones in the area,
possibly Home Valley Knoll that was to the south of the dirt road
you drove in on to get to the coordinates.
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.
At the coordinates you can look down the cliff at the boulders
of basalt that have fallen off the cliff and at the cliff side to
see columnar jointing. While not the best example, you can still
see the pattern. (The Giant’s Causeway is one of the best)
Typically the columns have 5 or 6 sides, but can range from 3 to 7
sides.
These columns form as the lava cools. As the lava cools it
contracts and cracks. These cracks typically meet at approximately
120 degree angles, forming roughly hexagonal columns. In the best
examples, these columns can be hundreds of feet long.
There is a trail that goes down the side of the cliff. The trail
is steep and difficult.
Logging requirements:
Send me a note with :
- The text "GCZ5YM Lava Point - Zion NP" on the first line
- The number of people in your group.
- Have a look around on the point. Find what you think are 10
seperate columnar joints and count the sides.
- Optional--Please post a picture of youself or other member of
your party at the cache site.
The above information was compiled from the
following sources:
- Hamilton, Wayne L. 1987,
Geological Map of Zion National Park, Utah Miek, Robert F., et.
al., Geology of Zion National 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
- http://volcano.und.edu/vwdocs/vw_hyperexchange/col_joint.html
Placement approved by the
Zion National Park