For 100 years, the National Park Service has preserved America’s special places “for the enjoyment, education, and inspiration of this and future generations.” Celebrate its second century with the Find Your Park GeoTour that launched April 2016 and explore these geocaches placed for you by National Park Service Rangers and their partners.
geocaching.com/play/geotours/findyourpark
Please obey all trail and Park rules. Stay on the trail to protect plant life, to keep from disturbing animals (even the small ones hidden under the fallen leaves), and to keep erosion to a minimum.
Turn to Stone (Nothing to do with ELO)
Photo by Ammosuperman
Clues From the Past
The odd surface of this rock can tell us a tremendous amount about the conditions of the area in the distant past. For instance, this area this rock (way back when it was only billions of tiny pieces of sediments) was in was at one time flooded with water. It also tells us that it became very dry shortly after being flooded, and then it was buried under even more sediments as it was flooded again. Then some time later it became compressed and over millions of years, this group of sediments became solid rock. We also know that the entire area was level, as in flat, with no hills in the immediate area.
How can we tell all of this from viewing only the surface of this one particular, rather small rock that has been dislodged from the side of the hill? The pattern in this rock as seen in the picture indicates that at least this portion of the area was at one time flooded. This means that there had to be a source of water that carried sediments to the location near here. That the waters receded or evaporated away, and that the “mud” quickly lost the water it was holding. As this material dried, (sometimes called desiccation) it contracted forming gaps or cracks, in the surface. After this period of desiccation, the area was again flooded and the new sediments were deposited on top of the cracks in the mud, this preserved the pattern we see here today. Over millions of years the pressure (and the heat brought about by the pressure) has cemented the fine grained sediments together, forming sedimentary rock. We know the area where these cracks first formed was level because it held shallow standing water.
As we look around the area of western Virginia, northern Tennessee, and southeast Kentucky, we see that this entire region has been uplifted. The hills that you see all around you are the result of earth’s crustal plates colliding and raising the land. At this location we are just a little too far away to see the tilted layers of rock, the inclines and synclines, and other more direct evidence of these collisions. However, at one time this area would have been subject to earthquakes as a result of this crustal movement.
Modern Mud Cracks:
Ponds that have been drained, mud puddles that have dried up, river or stream banks that have been flooded and the waters receded are all prime areas to find modern day mud cracks.
Photo from wildnatureimages.com
Such formations have undoubtedly formed millions of times throughout the world and then disappeared again with each new heavy rain or flood. Some perhaps, just a few, have also been covered with sediments and not been destroyed, and may someday form fossil mud cracks for our distant relatives to discover.
This Particular Rock:
The rock seen here at these coordinates has been weathered and eroded. There are no longer the sharp edges you would have seen millions of years ago on the individual sections as in the photo above. But the general pattern remains. If you look closely, you can still see the “V” shape of the cracks that formed so long ago. It is even more evident when you get up close and personal, running your fingers along the grooves and feeling the texture of this ancient surface of a long forgotten waters edge.
Added Bonus EarthCache:
Farther down the trail is another site that shows the area was at one time under water. The ripple marks seen at that location (N36 39.842, W083 26.413) likely formed in the same time period as these ripple marks. Both rocks show formations indicating ancient shallow water.
Also don’t forget to check out the other great EarthCaches up the trail to Sand Cave and to White Rock.
How to get there:
It takes 90 minutes to reach the Ewing Trail from Knoxville. Take Interstate 75 North to the LaFollette exit, and follow State Route 63 all the way to Harrogate. At Harrogate, turn left at U.S. Highway 25E, and take a right onto U.S. Highway 58 East at Cumberland Gap. Follow Highway 58 for 12 miles to Ewing, Va., and take a left onto State Route 724. The Ewing Trail starts at the end of Route 724, which is also marked as Sand Cave Road.
Permission for this EarthCache is allowed by the Cumberland Gap National Historic Park. Always ask for permission before placing an EarthCache in the park.
Qualifications for Credit:
To get credit for this Earthcache email the answers to the questions below and post a picture of you and your GPSr with the mud cracks in the background. Failure to answer the questions or logs with no pictures will result in the log being deleted. If it is not possible to get a picture because of camera problems, for instance the batteries died or you dropped your camera and it rolled down the side of the hill, email us first and we will work something out.
Questions:
1. What process formed these mud cracks?
2. What type of rock is found at this location?
3. In inches, what are the length and width of the largest section ( Note: the rock is not completely covered with these cracks)?
Credits and Ammosuperman EarthCaches
This EarthCache was created by a team of two Platinum EarthCache Masters, Ammosuperman EarthCaches are a collaborative effort. We have used resources such as the Internet and magazine articles as well as personal experience in visiting the sites, as research tools in its construction. Our goal is to learn more about our planet and to pass along what we have learned to others having similar interests. We hope you enjoy the experience.
Special thanks to Scott Teodorski of the Cumberland Gap National Historical Park for allowing this EarthCache and for seeing the educational benefit of such endeavors.
