Justjoee and I stumbled upon this place during the summer of 2015; and both were amazed at what we found here. Hope you enjoy this spot as much as we did :)
What is Karst?
Karst is a term applied to areas where extensive dissolution of rock has led to the development of subterranean channels through which groundwater flows in conduits (enclosed or semi-enclosed channels). These conduits can vary in size from slightly enlarged cracks to tunnels many meters in diameter and many kilometers in length.
At this location, you are going to a few different types of geology that encompass what make up Karst. Below are the most common examples you will likely find in this area, and in other areas that contain karst.
Types of Karst?
Sinkholes - Sinkholes form when rock has been removed by dissolution and a void has been created underground. When rock above this void collapses, a sinkhole is created.
Disappearing Streams - This feature is when a river, stream or groundwater slowly dissolve a channel(s) through rock, often ending with the water or stream disappearing beneath the rock. .
Karren - These are small solution pits, grooves and runnels, dissolved into rock which are collectively called karren. Individual features are rarely longer or deeper than 10 m, but frequently they are densely clustered and dissect larger areas, referred to as limestone pavement.
Limestone Pavement - A limestone pavement is a natural karst landform consisting of a flat, incised surface of exposed limestone that resembles an artificial pavement.
How is Karst formed?
Limestone is a type of carbonate rock — that is, a rock made up primarily of a carbonate mineral which, in the case of limestone, is usually calcite or aragonite. These are both forms of calcium carbonate (CaCO3). Over time, limestone may be dissolved by carbonic acid (i.e., carbon dioxide dissolved in water). Carbonic acid is formed when rain picks up CO2 as it falls through the atmosphere. Once it hits the ground, it may pick up more CO2 in the soil, turning into a weak carbonic acid solution. When this solution seeps into limestone bedrock via cracks and fissures, larger openings are created. Over the course of thousands of years, this erosive process creates underground drainage systems and caves.
Logging the Earthcache
In order to log this cache you will need to visit the posted coordinates, and then answer the following questions. Please send your answers to me via email, or my GC profile. Please don't include them in your log. I love looking at photo's in logs, but please try and not upload photos that give away the answers (except for the optional task #4). Thanks in advance :)
1. Of the various types of Karst you might see here, what is the most obvious type you see at this location?
2. Estimate how long the above feature is; and if there is an elevation change from one end to another. If there is an elevation change, how much of a change is there?
3. Thinking back in time, what other geologic feature would this have been before the carbonic acid created the karst found here. Why do you think so?
4. Optional - upload a photo with your log taken showing an example of Karren that you found at this site, and describe what type of Karren it is (in your email); small solution pits, grooves or runnels.
Safety First
Please be careful while doing this cache. You are near water, rocks and hidden underground tunnels. Please be VERY careful while exploring, and no swimming above the Karst; it's just too dangerous.