ORIGIN AND SITE SPECIFIC LESSON
This stone was found on Straight Creek in Bell County, Kentucky. It began its formation 240 million years ago. This stone is representative of the sandstone which makes up large portions of the Pine Mountain area. This rock is called "Turtle Rock" because it resembles the shell of a turtle.
The exact process that creates "turtle rocks" is not well understood. One theory suggests it is the result of spheroidal weathering. In this process, water percolates through cracks and between individual grains in the rock, loosens and separates layers of the rock. It is further believed that the weathering of the rocks strongly influences the polygonal joint pattern seen in all "turtle rocks".
PSEUDOFOSSILS
There are many features in rocks that appear to be fossils when they are really not fossils. These features or rocks are called pseudofossils, which is a natural object, structure, or mineral of inorganic origin that may resemble or be mistaken for a fossil (Glossary of Geology, 1989).
Turtle Rock is an example of pseudofossils called concretions and nodules. It is a septarian concretion. Septarian concretions vary in size and are characterized by an irregular polygonal pattern of cracks that are filled or partially filled by crystalline minerals, usually calcite. The origin involves the formation of aluminus gel, case hardening of the exterior, and shrinkage cracking. The shrinkage cracking is due to dehydration of the colloidal mass in the interior and vein filling (Glossary of Geology, 1987).
In order to receive credit for this Earth Cache:
*All required information MUST be completed in order to earn credit for this earth cache. Enjoy the journey (ie., learning adventure) as well as the destination (ie., earned smiley). Take only pictures. Leave only footprints.
To earn credit for this earth cache, complete the following answers and submit via www.geocaching.com profile. Each cacher must submit his/her individual answers. On the first line, write the name of the Earth Cache, Turtle Rock.
According to signage near the stone, answer the first 4 questions.
1. Describe how this rock began its formation.
2. What is the type of pattern on the stone?
3. What was deposited into the seams?
4. Describe how the stone came out as a unit?
5. What are the length and width of Turtle Rock?
Kentucky State Park Permit #15827PM04
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