ORVEC: Sink EarthCache
Hidden : 10/13/2012
Difficulty:
3.5 out of 5
Terrain:
5 out of 5

Size: Size: other (other)

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Geocache Description:



Sinkhole



sink·hole
noun /ˈsiNGkˌhōl/  sinkholes, plural A cavity in the ground, esp. in limestone bedrock, caused by water erosion and providing a route for surface water to disappear underground
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The listed coordinate will take you to the only visible occurrence of a sinkhole within the banks of the Ohio River. The limestone ledge and sinkhole in these images is only visible for a few months each year.

Over 350 million years ago, this region of Kentuckiana was under a vast tropical sea. Crushed bones and shells of animals as well as decayed algae that once lived in this sea created a limestone rock layer. The waters of the ancient sea receded and the layer of limestone, known as the Jefferson Limestone, was buried beneath layers of the clay and sand. When the Ohio River was formed by meltwaters left by receding glaciers some 10,000 years ago, the overlay was eroded and the limestone was exposed.

When rain falls through the atmosphere, it combines with carbon dioxide to form a weak carbonic acid which soaks through the soil dissolving the limestone layer. As the limestone layer dissolves, caves and holes under the ground are formed. Karst Topography is the term used when sinkholes are common in an area.When logging please send an email answering the following questions:

Optional: To share your experience, please post photo of yourself or your GPSr at the listed coordinate with the waterfall (not the sinkhole) in the background

And to demonstrate the educational value of this Earthcache, please send answers to the following questions:

1. What is the diameter of the sinkhole?
2. What is the approximate depth of the sinkhole (do not use your leg).
3. What type of bedrock is this sinkhole formed in?
4. Drag a patch of nearby moss over and guide it into the sinkhole to create a muddy water trail. Where does it emerge?

WARNING: If launching from Harrison Avenue expect possible strong currents. Call 502.775.5056 and listen to the one-minute recording. This cache was placed while the lower gauge was eleven feet and McAlpine was 'running seven feet of dam on the lower site and five units on the hydro' (10-5-12). If the lower gauge is 20 feet or above this site is under water.

Additional Hints (No hints available.)



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