Hot Springs County is located in the southwest corner of the Bighorn Basin. Much of the county is mountainous, with the Owl Creek Mountains on the south and the Absaroka Range on the west. The northeastern part of the county opens into the Bighorn Basin. Several large hot springs rise near the mouth of Wind River Canyon and flow into the Bighorn River. These springs are similar to those in Yellowstone but are not caused by the same process. The Yellowstone thermal features come from a magma heat sources relatively close to the surface (3 to 8 miles below the surface) which heat the ground water causing the hot springs and geysers; These hot springs are created by ground water traveling deep underground being heated by the underlying basement rock, and then surfacing through fractures created by an uplift in the basement rock. This process is outlined on the sign in front of you.
The Owl Creek Mountains (located south of your current location) are made of warped and uplifted sedimentary rocks. It is these rocks which become part of the focus for this earth cache since they are responsible in part for creating the hot springs that lie in front of you at this location. The water that comes out of the hot springs at this location actually started as rain or melted snow that enters the hydrologic cycle 20 miles south of here as ground water. The Owl Creek Mountains are made up of several different types of layered rocks. If you took them and cut a cross section of them you would see the many different layers that make up the mountain range. Fortunately we have that with the Wind River Canyon that cuts the mountain range in half. OK so back to the rocks, and eventually the springs. From top to bottom in the mountain range we have Madison Limestone, Bighorn Dolomite, Gallatin Limestone, Gros Ventre, Flathead Sandstone, then the Precambrian basement rock (see pictures below).
The water filters through the layers of rock and then runs parallel to the Precambrian basement rock for miles deep below the surface of the earth where it is heated by pressure and the hot underlying basement rock (see large diagram on the sign in front of you). The water dissolves some of the minerals found in the limestone's, dolomite, and sandstone layers and carries those minerals with it when it comes back to the surface. The hot water runs into an uplifted portion of the basement rock which has caused fractures that extend down from the surface that allows the water to surface at this exact location. Thus we end up with hot mineral water (135 degrees at the mouth of the Big Spring 125 yards to your left as your looking at the sign) from the springs that form the pools behind the sign.
Logging requirements updated 5/21/2020
The answers for 1-3 are located on the "Geology of Hot Springs" sign. Please read all of the text on the sign before attempting the questions.
In order to claim this earthcache you must answer the following questions:
1. What is the geologic structure that caused the fractures that extend down from the surface? What shape is it? (2 answers)
2. How does the mineral water at these hot springs create the amazing travertine terraces that you see throughout the park?
3. What chemical in the mineral water accounts for the unusual odor of the hot springs?
4. At this location you are standing near a bridge with spring water running under you to the large pools. Estimate how warm the water at this location is. (hint: your average body temperature is 98-99 degrees, and the average temp at the spring is 135)
5. Post a picture of yourself, or a personal item at the site with an identifiable part of the park (Pools, terraces, springs, the swinging bridge) in the background that shows you visited the site. REQUIRED
NOTE: If you post ANY answers to the questions above in your log (encrypted or not) it will be deleted. If you fail to send an e-mail within 7 days of your 'found' log, your log will be deleted. The photo in task 5 is required and is a viable logging task (click on the work "required" at the end of task 5 to go to acceptable logging requirements for earthcaches). If you are caching as a group, only one e-mail needs to be sent with answers, please list the members you are caching with by caching name. Every account claiming a find must have a photo.
Information sources:
1. http://www.wsgs.wyo.gov/
2. Wyoming State Parks & Cultural Racecourses
3. Photos taken and edited by Alen VerPloeg