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
Ripples Along the Trail—Back in Time
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.
At this location the ripple marks are located on the side of the rock that is facing the benches. They are especially easy to see if it has recently rained, but you can see them if you are close to the rock and off to the left or right somewhat.
The Ripples
Photo by Ammosuperman
These strange looking rock formations located at this resting area are called “ripple marks”. They are formed by shallow water flowing over a bed of sand or other sediments, or by wind-driven wave action in shallow water, again over small sediments.
The ripples formed in shallow water by waves, (imagine small waves lapping at the shore of a very shallow area of a lake) are called wave-formed ripple marks. These are distinguishable by the symmetrical shape of the individual ripples. Another type, called current formed ripple marks are asymmetrical in shape with gentle slopes on the up-current sides and somewhat steeper slopes on the down-current sides of the ripples. Other more erratic ripple marks are formed where two separate wave patterns, traveling in slightly differing directions meet. These are classified as interference ripple marks.
These patterns are usually small and close together, but not always. Very large volumes of fast moving water can form very large ripples. The Channeled Scablands in Washington State were formed when an ancient, very large lake burst through its natural dam and flooded many thousands of acres of land in a short amount of time. The ripple marks it left can still be seen today and may be 100 yards in length or longer, with heights resembling small hills.
The formations seen at this site were almost certainly caused by shallow, slowly flowing water moving over sandy or muddy areas. At some point in the history of these formations, the ripples were covered with other layers of sediment, without disturbing the patterns we see today. In time there were many other layers deposited here, compressing the layers by their own weight effectively forming fossil wave marks in the rock.
Millions of years later, as erosion slowly removed the layers of rock the ripple marks have been exposed higher up on the hillside. As erosion is an ongoing process, these remnants will eventually disappear, worn away by the same processes that destroy mountains, turning them into sediments. It is ironic that these marks were formed in shallow water millions of years ago, and today the rock that they have been preserved in is so high on the hill. The water and wind created these formations, and will destroy them in time.
The Rocks of the Area
These particular formations are made of sandstone, as are the other rocks seen at or near this location. Sandstone is a sedimentary rock that was originally deposited as fine grained particles that settled to the bottom of a large shallow sea which covered this area millions of years ago. At this location the sea was so shallow that the ripples formed by surface waves. In this water would have perhaps lived snails, worms, and other invertebrates.
Added Bonus EarthCache:
Farther down the trail is another site that shows the area was at one time under water. The mud cracks seen at that location (N36 39.594, W083 26.081) 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 ripple marks 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 ripple marks?
2. What type of rock is found at this location?
3. What is the texture of the rock, smooth, rough, glassy, etc.?
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.
