VFEC2: Parking Lot Stromatolites EarthCache
VFEC2: Parking Lot Stromatolites
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VFEC: Valley Forge EarthCache
The above coordinates will take you to the wall of an abandoned dolostone* quarry. Dolostone is a sedimentary rock made up of a high percentage of dolomite. Dolomite is composed of calcium magnesium carbonate (CaMg(CO3)2) .
Dolomite is used as an ornamental stone and as part of the materials used for cement.
The layering produced during the formation of the rock is clearly visible in the face. Originally, the rock formed horizontal layers but are now inclined towards the south.
Question: Estimate the current angle (in degrees).
The change in orientation occurred during the mountain building activity that started about 480 million years ago.
Thin, irregular to wavy laminations up to an inch thick are common in some rock layers. These stromatolites were formed by mats of interlayered algal colonies and fine sediments on the seafloor. Similar structures in older rocks represent some of the first recorded life on earth. Currently stromatolites are forming in Shark Bay on the western coast of Australia.
*The use of the term dolostone is not recommended by the Glossary of Geology published by the American Geological Institute (AGI). The preferred term is dolomite rock because the name dolomite was first applied to the rock during the late eighteenth century and thus has technical precedence.
To log this earthcache, e-mail me an answer to question in the text.
Sources:
www.wikipedia.org
http://www.dcnr.state.pa.us/
http://www.nps.gov/vafo/naturescience/geologicformations.htm
http://www.snomnh.ou.edu/collections-research/cr-sub/invertpaleo/common_fossils_of_ok/Paleobot/Stromato.htm
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Valley Forge Caching Info:
It is required that cachers stay on marked trails at all times.
Only Earthcaches and virtual stages of caches may be placed on Valley Forge land.
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Additional Hints
(No hints available.)