I know, you’re thinking what do Cataracts in people’s eyes have to do with a Geology lesson? Well has it turns out like many other words Cataracts has two meanings and one of them has to do with Geology.
Cataracts in Geology are very, very large waterfalls! Sometimes they are called cataracts when a large waterfall, falls over a precipice like the example below.
Now you’re also thinking, ok a pothole, this has to be in the street right? Then maybe this is an urban Earthcache? Well it turns out a Geology Pothole is formed when a cylindrical pit is formed in a channel or bed of rock when a stream was very turbulent.
When the rock is Sandstone like it is here the indentation of a rock may start this process where a stone or stone’s action of abrasion are tossed around by the action of water currents. Then after years and years it forms a Pothole.
While a creek most of the time is very slow, if the area is a narrow canyon, or the rocks form little cliffs or the angle of the creek drops and forces the water to move faster, these will all help to start a Pothole.
Once a Pothole gets going, as long as the water keeps moving and the current cooperates it gets deeper and deeper like the examples below.
You’ll also notice over time this example has been worn very smooth.
Logging Requirements: Please E-Mail me the answers, don't post any pictures of the site itself.
1. Type in "GC7C9N8 Pothole formed by a Cataract"and how many with you today?
2. Do you think this was formed by a Cataract?
3. What is the diameter of this pothole?
4. How deep is it?
5. Are there any stone grinders left in this example?
The following Material were used for Reference:
- Cal tech Geology research
- U.S. Department of the Interior, Professional papers and Geological surveys
- Wikipedia
- California Institute of Technology
- https://people.uwec.edu/jolhm/interstate2006/potholes.htm