This Earth Cache will show you a great example of Frost Wedging erosion. Across the street from the posted coordinates you will see a rock road cut formed when frog hollow road was rerouted through higher ground. The rock cut shows the common local formations of the Ordovician Period, The Jefferson City Dolostone, and the Plattin Sandstone. (See “Of Plattin Sands” GC7V162 for a better example of pure Plattin Sandstone.) What makes this area particularly interesting is the Frost Wedging and erosion that has occurred due to the road cut. The cut has revealed rock that would not normally be exposed. This allows water to seep into cracks in the rock surface. As the water freezes the stones are wedged apart and eventually fall down the side of the cut. At the bottom of the cut you can see the piles of rock that have been forced off of the wall. One of the things that makes Frost Wedging quite dangerous is it’s ability to weaken and erode normally stable formation. The “Freeze Thaw Cycle” as it is sometimes called is a very interesting example of erosion, and is often seen in limestone bluffs, Such as this one. This process is also common in areas of high humidity and areas of porous rocks like Sandstone. Similar process exist in asphalt pavement and concrete.
Logging requirements: 1 What is the dominant color of the exposed rock cut? 2 What evidence of Frost Wedging do you see on and around the rock wall? 3 Name one type of rock that is commonly affected by Frost Wedging. 4 Why do you think there is more frost related erosion here than in other areas. 5 Although not required it would be great if you could post a picture of the rock wall in your log.
There is parking available down the street to the north, or park at the Greenway parking area and walk.