Ozark Sinkhole EarthCache

Thanks to the Ozark Parks and Rec department for permission to experience this earth feature.
This earthcache and the park are only available from sunrise to sunset.
Stay within the park and do not enter people’s property that surrounds this park.
Ozark Parks and Rec is not liable for your safety.
Do not enter the sinkhole area, it is clearly marked by a fence.

Sinkhole

A sinkhole. It is a natural depression in the Earth's surface caused by erosion. Water seeps into cracks in the bedrock and erodes away at it. Over time the cracks get bigger and bigger and soon a cave is formed. Size of the cave below is not important, just know that its down there. A sinkhole starts to become visible when the ground starts to sink lower than the surrounding ground. Sometimes this can happen in an instant and sometimes this can happen slowly over a long period of time.

Source: Photo

Solution Sinkhole

Solution sinkholes occur in areas where limestone is exposed at land surface or is covered by thin layers of soil and permeable sand. This type of sinkhole usually forms as a bowl-shaped depression with the slope of its sides determined by the rate of subsidence relative to the rate of erosion of the walls of the depression from surface runoff.

Source: Photo

Collapsed sinkhole

collapse sinkholes occur where a solution cavity develops in the limestone to a size such that the overlying cover material can no longer support its own weight.

Source: Photo

Karst Topography

Karst topography is a geological formation shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite. Karst landscape, which occurs in many parts of Eastern Tennessee, has springs, sinking streams, caves, and sinkholes. The karst terrains of Tennessee are mostly on limestone and formed over hundreds of thousands of years. As water moves underground, from hilltops toward a stream through tiny fractures in the limestone bedrock, the rock is slowly dissolved away by weak acids found naturally in rain and soil water.

Source: http://www.esi.utexas.edu/outreach/caves/images/karst/karst_fig11.jpg

Missouri is known as the cave state with new caves being recorded every year. As of 2013 there are over 7,500 recorded caves in Missouri, with the vast majority of them in the Ozark region of Missouri. There are more caves in Missouri then in any other state.

**Logging requirements**
DO NOT POST ANSWERS IN YOUR LOG.
Send the following answers to me via email.

1. The text "GC4P5PG Ozark Sinkhole " on the first line
2. Is this a “Solution sinkhole” or a “Collapsed sinkhole”?
3. While standing along the fence, count the number of sinkholes within the area
4. What is the main cause why this sinkhole would grow? (Look to the N/E and the S/W areas of the park for clues)
5. ID the sign within the park, what is the object right above the word “of”?