Sunday, April 15, 2012

TRAVERTINE AT UTAH GEYSERS


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.

2 comments:

  1. I just got back from a trip to Crystal Geyser, where I took some samples of banded travertine from a talus slope nearby. I was having a very hard time identifying the rock until I found your post here. Thanks for the information!

    ReplyDelete