The Buck Stops Here EarthCache

This cache has been archived.

Geocaching HQ Admin: It has now been over 30 days since Geocaching HQ submitted the disabled log below and, unfortunately, the cache owner has not posted an Owner maintenance log and re-enabled this geocache. As a result, we are now archiving this cache page.

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Hidden : 2/20/2009
Difficulty:
1.5 out of 5
Terrain:
1.5 out of 5

Size: Size: not chosen (not chosen)

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Geocache Description:

   This Earthcache will take you to the east side of a roadcut along Hwy80. At ground level you will find a coal seam that stops.....abruptly.
   OK.....There is no fault plane here.....So how did this happen? Why does it end so suddenly?



   Let's take a look at the coals formation here, and the reason for this coal seams abrupt ending.
   The layers of coal beds in East Kentucky's coal fields are intermixed mostly with shale and sandstone. Most of the major coal beds here were formed as widespread peat swamps, or mires, during the Pennsylvanian Period. (286-320mya) Shallow seas covered parts of Kentucky as many as 50 times during the Pennsylvanian. When the sea levels fell, the seas withdrew to the edges of the continent and large rivers snaked across Kentucky. The peat swamps formed on extensive coastal plains. When sea level rose, the peat deposits were covered by muddy sediments. When sea level started to lower, coastal plains and river deltas built back over the muddy sea sediments. During the next low sea level, coastal peat in swamps was again deposited over the plains sediments. The peats, mud, and sand, buried by increasing layers of sediments, became compacted. Eventually the peat transformed into coal and the muds and sands became cemented, transforming them into shales and sandstones.

   

   Miners occasionally call this type feature a "fault", but inasmuch as it is related to erosion, rather than to fracturing and vertical displacement of the coal seam, that term is perhaps the most incorrect. Of all the names that have been applied to this feature,"washout" may be more appropriate.
 
    The term “fault”, as used, means a tectonic fault, which is a sharp displacement of strata along a plane of offset that is continuous into the subsurface beneath the coal.
   This type of feature should not be confused with sandstone and paleoslump margins either, which can look similar to cutouts.   
   
   A washout, or channel cutout, as they are referred to, is what has happened here. After deposition of the peat/coal layers, erosion by a stream/river channel has made the sharp division that you see at this location. Subsequent sediment layers then overlaid the peat/coal seams and added many feet of rock overhead. The illustrations on the right depicts the likely sequence, over millions of years.
   
   These cutouts, extending through several counties in East Kentucky, have an overall east–west orientation, and makes several sharp, northeast–southwest and northwest–southeast bends. The locations of most of these cutouts have been discovered through core-drilling and have been mapped, as shown in the example below.







To log this EarthCache:
Post the usual photo of you with GPSr at the cutout.(optional)
Measure, or estimate, the the visible thickness of this coal seam at the cutouts end.
Email the info, without posting.

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