EARTHCACHE REQUIREMENTS
Each cacher must send his/her own answers BEFORE logging a find. Enjoy the journey (learning adventure) as well as the destination (smiley earned). Remember to take only pictures and leave only footprints. To get credit for this Earthcache, complete the following tasks:
1. MESSAGE …. Explain the main difference (other than color) between the types of shale.
2. MESSAGE …. a. What is the size of the bare spot showing Mccready shale. ... b. What colors do you see?
3. MESSAGE …. Explain (scientific or creative) why this is the only bare spot on the hill . A local historian said that bare spot showing Mccready shale has remained bare for 17 years.
4. LOG …. Post a picture at or near the posted coords. This picture is your log signature verifying that you were at the earthcache.
OPTIONAL - Please respect the time and effort involved in creating this earthcache by adding A and B to your log.
A. JOURNEY OF THE MIND ... Science explains what we observe. Relate (in your own words) something you found interesting in the reading. This adds to your learning adventure and your log.
B. JOURNEY OF THE HEART ... Art shares our personal experience of what we see. Share something special you found on site, and why it is special to you. This is a memorable addition to your log and will make other hearts smile.
OPTIONAL - NEARBY EARTHCACHE GC12RWD
You can view the Saltville Fault on the opposite hill. The Saltville Thrust Fault extends over 400 miles across southwest Virginia into northeastern Alabama. It is one of the longest faults of this type in the eastern U.S. The Saltville Fault has a vertical displacement of over 17,000 feet and covers the nearly pure salt.
MUDSTONES AND SHALE
"Mudstones and shales are made of silt- and clay-sized particles that are too small to see. The only difference between mudstone and shale is that mudstones break into blocky pieces whereas shales break into thin chips with roughly parallel tops and bottoms. Both are made of ancient mud." Mudstones are subdivided into siltstone (feels gritty) and claystone (feels smooth).
SHALE (Compacted mud)
WHAT DOES IT LOOK LIKE - Shale may be black, gray, red, brown, dark green, or blue. It is fine grained, so particles usually can not be seen. When moistened, shale usually smells like wet mud.
WHAT MINERALS MAKE UP THE ROCK - Clay minerals; Sometimes with some quartz sand, pyrite, gypsum
HOW WAS IT FORMED - Clay sediments settle in quiet lakes, lagoons, bays, or off-shore areas. When buried and compacted the clays become shale. Iron oxides often help to cement the particles together.
TYPES OF SHALE
BLACK - lots of organics
GRAY - low organics
RED - fully oxidized iron
GREEN - partially reduced iron
MCCREADY - salt and gypsum
MCCREADY SHALE (aka Maccrady)
The Maccrady is found in narrow bands from the Virginia-Tennesse line northward for about 120 miles. The Maccrady is bounded on the southeast by the Saltville overthrust where Cambrium rocks are thrust over the Maccrady. It is bounded on the northwest by the Little Valley Limestone. This shale consists predominantly of gypsum, anhydrite, salt and limestone in a matrix of red and green shale.
RESOURCES
https://books.google.com/books?id=F8dRAQAAMAAJ&pg=PA209&lpg=PA209&dq=mccready+shale&source=bl&ots=ap2RWWEYf8&sig=l2MEnOO6lva-utRhDOsEGZ5rw3o&hl=en&sa=X&ved=0ahUKEwj0pb7TtvDRAhWk14MKHUsZCiAQ6AEIRjAI#v=onepage&q=mccready%20shale&f=false
http://www.pitt.edu/~cejones/GeoImages/5SedimentaryRocks/ClasticSedRocks/MudstonesShales1.html