Large piece (2.5 feet in length) of travertine (labeled geyserite) collected many years ago at Crystal Geyser and now displayed at a rock shop in Moab, Utah. |
As I am fond of stating, a long
time ago, several students participated in a field trip to the San Rafael
Swell in central Utah. Among other localities we visited were a couple of
"geysers". I found these features to be interesting since my
previous experience with geysers had been in Yellowstone and Iceland, the
latter through books and television. The first locality was near a
gasoline station/cafe/store (now abandoned) at Woodside, Utah, on UT 6 south of
Price/Wellington. Our class instructor, who was from the area, told us about
the D&RGW railroad drilling a water well that somehow failed, turned into a
bubbling carbon dioxide mudpot and later into a cold water geyser.
Woodside
Geyser in 2004. Photo courtesy of J. Alan Glennon
|
Continuing down the road we took in
the "more famous", and named, Crystal Geyser about 9 miles southeast
of Green River, UT, along the river. This cold water geyser seemed more
spectacular since it had created large terraces (sort of reminded me of
Yellowstone) and the eruption was quite impressive. I collected the
requisite rock sample and we moved on to the more important elements of
collecting fossils in the Swell. And, I mostly forgot about these
features.
Banded travertine collected at Crystal Geyser in late 1960's. Dark bands are iron-rich minerals. |
I recently was in Moab, UT, and
during a browse in the local rock shop came across a large piece of banded
travertine labeled "geyserite". That particular rock triggered
something in the back recesses of my mind--a sample collected decades ago at
Crystal Geyser, and the fact that geyserite is a hydrous silicon dioxide.
So, in my mind the rock shop rocks are mislabeling pieces of travertine, a form
of calcium carbonate. Mislabeled or not, that specimen rekindled my
interest in these geysers and their formation.
The Woodside Geyser is on private
land and unavailable for close examination by causal rock hounds, and although
I waited for a time in early April 2012 along the highway, I did not see an
eruption. According to J. Alan Glennon (2005) "the activity of
cold-water geysers is similar to their hot water counterparts, except that CO2 bubbles drive the eruption instead of steam. In
cold-water geysers, CO2-laden water lies in a confined aquifer, in which water and CO2 are trapped by less
permeable overlying strata. If a well is drilled through a confining layer into
a CO2-laden aquifer, the borehole provides a path for the pressurized
water and CO2 to reach the surface. A decrease in pressure of the water column
allows CO2 to outgas and any existing CO2 bubbles to expand. This boiling deep
in the system is comparable to water flashing to steam in a hot water geyser.
As the CO2 outgasses, it displaces water and starts the eruption."
Crystal Geyser is the
result of drilling (mid 1930's) the Glen Ruby #1-X exploration well into a CO2
charged aquifer somewhere about the 200 yard subsurface level (Jurassic
sandstone?). The degassing of the CO2 and the charged water periodically
reach the surface and travertine is deposited, including some terraces.
There are also outcrops of pre-geyser travertine along the Green River that
were deposited by CO2-driven springs. This CO2 may have originated several miles in the subsurface (Allis,
2005).
Crystal Geyser at maximum eruption in 2005. Photo courtesy of Gouveia2. |
Geologists like to study
subsurface CO2 in relation to possible future storage of atmospheric CO2 in
order to reduce global warming, or to actually produce rather pure CO2. The
Colorado Plateau has at least 9 producing or abandoned CO2 fields (Allis and
others, 2001), mostly associated with fault-bounded anticlines (Shipton and
others, 2004). So, as I understand the situation from the
literature (Allis and others, 2005), there are a couple of areas in this part
of Utah that contain anomolously high amounts of carbon dioxide in the
subsurface. Farnam Dome in central Utah has CO2 in the Navajo Sandstone
(Jurassic) at about 650 yards in the subsurface; however, there is not evidence
of leakage to the surface. Farnam Dome was a major producer of CO2 in
past years. A few miles to the south of Farnham Dome is the Ten Mile Graben/Little
Grand Wash Fault Zone where faulted structural zones allow CO2 leakage, in
charged water, and the deposition of surficial iron-enriched travertine.The
Glen Ruby well was evidently drilled along the fault zone and is now Crystal
Geyser. Water actually "blows" out of a pipe added to the
well in the early 2000's.
All-in-all, these
geysers are quite interesting, the travertine (not geyserite) is nicely banded
(with iron-rich dark bands), and the eruption of Crystal Geyser is pretty
spectacular. In addition, there are several other cold-water springs and seeps
in the area, and some travertine deposits from previous springs are located on
surronding hills. However, please do not destroy the travertine at the
geyser site and if you need a piece, purchase such at a local rock shop.
mike
REFERENCES CITED
Allis, R., D. Bergfield,
J. Moore, K. McClure, C. Morgan, T. Chidsey, J. Heath, and B. McPherson, 2005,
Implications of Results from CO2 Flux Surveys Over Known CO2 Systems for
Long-term Monitoring: Fourth Annual Conference on Carbon Capture and
Sequestration (http://geology.utah.gov/emp/co2sequest/pdf/allis0505.pdf)
Allis, R., Chidsey, T.,
Gwynn, W., Morgan, C, White, S., Adams, M., and Moore, J., 2001, Natural CO2
Reservoirs on the Colorado Plateau and Southern Rocky Mountains: Candidates for
CO2 Sequestration: First National Conference on Carbon Sequestration, www.netl.doe.gov/publications/proceedings/01/carbon_seq/6a2.pdf
Glennon, J. A., 2005,
Carbon Dioxide-driven Cold Water Geysers, www.uweb.ucsb.edu/~glennon/crystalgeyser/index.htm
Glennon, J. A.,
2005, Carbon Dioxide-Driven, Cold Water Geysers, http://www.uweb.ucsb.edu/~glennon/crystalgeyser/index.htm
Shipton, Z.K.,
Evans, J.P., Kirchner, D., Kolesar, P.T., Williams, A.P. and Heath, J., 2004,
Analysis of CO2 Leakage Through “Low-permeability” Faults from Natural
Reservoirs in the Colorado Plateau, Southern Utah in Baines, S. J. &
Worden, R. H. (eds.) Geological Storage of Carbon Dioxide. Geological Society,
London, Special
Publications 233.