This is an earthcache with no physical container to find.
In order to log a find and claim the 🙂 for this earth cache, you are required to complete/answer the following:
- Look at several rocks on the slope. Are they mostly angular (sharp edges) or rounded?
What does that tell you about how far they’ve traveled?
- Of these processes—freeze/thaw, plant roots, or water—
which do you think is the biggest factor here?
- Post a photo of you (or a personal item) at the site
At this location, you’re standing below a bluff made of layered sedimentary rock, mostly limestone from the Mississippian Period called Burlington Limestone. This rock formed millions of years ago when the area was covered by a shallow inlland sea. The limestone formed formed from marine life that settled on the sea floor and hardened over time. The shale layers formed from finer mud and clay that settled in quieter areas. These formed layers of alternating rock as you see before you.
But the real feature for this earthcache isn’t the cliff, it’s the pile of broken rock at your feet. This pile is called a talus slope, or scree. Every rock you see here fell from above. This EarthCache focuses on how solid rock breaks apart and slowly turns into the loose debris covering this slope.
What is a Talus Slope?
A talus slope (also called scree) is a pile of rock fragments that collects at the base of a cliff due to gravity. These rocks didn’t form here, they broke off the bluff and fell down.
The key process here is mechanical weathering, where rock is physically broken apart but not chemically changed. This mechanical weathering occurrs through water running through and over the rock (look, do you see wet rock on the bluff), freeze and thaw cycles where the water in the rock freezes and expands then thaws, and tree and plant roots growing into the cracks and weak spots in the layers, causing them to break apart.
How This Forms
1. Weak Spots in the Rock
-The bluff is layered. Cracks, joints, and softer layers create natural break points.
2. Rock Gets Broken Loose
-Water, roots, and freeze/thaw cycles slowly pry the rock apart.
3. Gravity Does the Work
-Once loose, the rock falls and builds the slope below.
What to Notice Here
- The rocks at the base are angular, not rounded
- There is a mix of sizes
- You can still see the source cliff directly above
That means:
- The rocks haven’t traveled far
- They fell, rather than being carried by water or other means
Thanks for completing this earth cache, and I hope you enjoyed it. In order to get the most accurate information I could, I used Missouri Geological Survey and United States Geological Survey. I also used ChatGPT to create the graphic and help edit.