Yellowstone National Park's renowned Upper Geyser Basin is a complex system of geothermal features, with geysers being the best known of the different geological features found at this location. More than 25 percent of the world's geysers are found within a square mile here, and it is believed that the natural wonders of the Upper Geyser Basin are what led to Yellowstone being founded as the world's first national park.
Three conditions must be met in order for a geyser to exist: there must be a plentiful source of water, a powerful heat source, and an underground "plumbing" system. The water that erupts from a Yellowstone geyser is heated to more than 450 degrees Fahrenheit due to contact with the complex heat source that underlies the park (see GC15A1H, "Yellowstone - North America's Hot Spot). The boiling point of water at sea level is 212 degrees Fahrenheit; at 7,500 feet above sea level — the average elevation at Yellowstone — water boils at 199 degrees Fahrenheit.
The heated water rising into a geyser's plumbing system is many degrees above the boiling point, and as it approached the surface it heats the cooler groundwater it encounters on the way. This newly added water acts like a big lid, capping the superheated water below it.
When a geyser's plumbing system has been filled with water, a process that can take days or just minutes depending on each individual geyser, the steam bubbles that previously floated to the geyser's opening become constricted; there are simply too many steam bubbles trying to escape. Water, however, can squeeze through the miniscule gaps between the bubbles. When this water escapes, it reduces the pressure within the plumbing system, causing the boiling point of water to drop to an even lower temperature. More water reaches the new boiling point, forming more steam, which swiftly expands to more than 1,000 times its original liquid volume, causing an explosion of steam and water to issue from the geyser's opening. This explosion, or eruption, continues until the plumbing system has been emptied of water or until the water drops below the boiling level. Once an eruption ends, the entire water-heating process begins again.
The Upper Geyser Basin can be broken down into several geyser groups, each with their own unique eruption frequencies and durations. The best known geyser group at the Upper Geyser Basin is undoubtedly the Old Faithful Group. This Earthcache focuses on a feature located in the nearby Geyser Hill Group: Solitary Geyser. At first sight, Solitary Geyser appears to be a large, steaming hot spring. However, Solitary Geyser is one of the Upper Geyser Basin's most regular performers, its minute-long eruptions occuring every four to eight minutes to a height of approximately five feet. A surprisingly short geyser, considering its size, but there is a reason for that: until 1915, Solitary Geyser had been known as Solitary Spring. Its transformation to geyser is a prime example of what happens when man tampers with nature.
Please note the difficulty rating of this Earthcache. Answering the questions will not just require reading a sign or information panel. Some comparative research to similar nearby features will be required. If you are having difficulty with your answers, consider visiting the Old Faithful Visitors Center or watching for the park ranger-naturalist that leads walks/talks around Solitary. To get credit for this Earthcache, please email us the following:
1. How did human interference cause Solitary Spring to become Solitary Geyser? (Extra applause if you can name the actual structure that was built, and a standing ovation if you can tell us when it was shut down).
2. How did construction affect Solitary Spring, causing it to transform into a geyser? Describe the geologic processes that caused this transformation. NOTE: This is NOT a rehash of question #1. We are asking for a geological description of how nature reacted to the human interference discussed in question #1. Please do not simply resubmit the same answer; that is incorrect! Also incorrect is noting that the water boiled at a greater depth. We are asking what physically changed in the geyser as a result of question 1; what was better accommodated in the plumbing system due to this change; and what in turn was affected by this, causing the spring to erupt.
3. Examine the shallower areas of Solitary Geyser. What colors do you see, and what causes these colors to exist?
4. Note the mineral deposits around the outer rim of Solitary Geyser. Describe the shape, size, and approximate distance of these mineral deposits from the geyser's "mouth." What are these mineral deposits made of? Name the geyser-specific mineral.
5. Optional:Post a photo of you or your GPSr with Solitary Geyser in the background. It doesn't have to be erupting at the time!
And now, a word from the Yellowstone Park Ranger:
Please remember to stay on the provided trail at all times. The ground around Geyser Hill and the entire Upper Geyser Basin is very fragile and at any time, a new geothermal system may make its appearance. For your safety and for the continued preservation of the geothermal features, please stay on the trail.
IMPORTANT! PLEASE READ!
Far too many geocachers log this Earthcache as found and then never send in their ADLs or send in incorrect answers and never bother to submit corrections. Team FMA created this Earthcache to share some of Yellowstone's geology with you, not to share a photo op with you. If you do not plan on submitting your ADL within 24 hours of logging this Earthcache as found, then please do not log it as found; use the "write a note" option instead. We will delete any found logs if we do not receive ADLs within 24 hours of receiving the found log. Those who submit incorrect responses will be given two weeks' time to correct their submissions before their log is deleted... and we are happy to give hints, but not give the answers away! Thank you for your cooperation.
Thank you for visiting our Earthcache!
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Yellowstone National Park
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