Welcome

Welcome to the Little Jerusalem EarthCache Series. This series was placed at the request of the Stae Park so it is important that you follow all rules to demonstrate how responsible geocachers are with the environment. Please stay on the trail and follow all rules as posted.  At no point, should you touch, collect, or disturb the environment except where specifically directed. Please enjoy this series of EarthCaches responsibly. There is a $5 day fee to access this park. 

Earth Science Lesson

When you approach GZ, along with a spectacular view you will also be able to observe a formation to your north just beyond the observation area in which you are standing. For this EarthCache, you will need to use the information below as well as your observations to answer a few questions. 

Plateau

A plateau is a flat, elevated landform that rises sharply above the surrounding area on at least one side. Plateaus occur on every continent and take up a third of the Earths land. They are one of the four major landforms, along with mountains, plains, and hills.

Fin

This geological formation, which is a narrow, residual solid wall of sedimentary rock that remains after the surrounding rock has been eroded along parallel cracks or fractures. The ribs are formed with a narrow Butte or plateau is developing a lot of vertical, parallel slits. There are two basic modes after erosion. The first is when water flows along the seams and cracks and opens them wider and wider, leading to erosion. The second where the rock is more difficult and erosion resistant than the adjacent rocks, causing poor rock to fall away. 

Fins are considered to be intermediary stages of many other erosive geological features, such as Windows, arches, and hoodoos. The formation of such features is the simplified four stages. The first step is a lift that leads to a deep parallel, vertical fractures within the plateau. The second step is weathering and erosion, that increases fractures, releasing fins. The third step is the erosion attacking the fins on the bottom, causing Windows and arches. The fourth stage is continued weathering that enlarges the holes, causing the arches and holes to collapse, creating spires, or hoodoos.

Erosion can influence the shape of a plateau. Soft rock often erodes away on the top of a plateau. Many plateaus are therefore topped with a hard, durable surface called caprock. Caprock protects the plateau from erosion of the soil underneath it. 

There are two main modes of following erosion. The first is when water flows along joints and fractures and opens them wider and wider, eventually causing erosion. The second is where the rock type (stratum) is harder and more erosion resistant than neighboring rocks, causing the weaker rock to fall away.

Logging Tasks

1. Estimate the width of the formation in relation to the height.
2. Do the sides of the formation appear to be generally vertical?
3. Do you see evidence of past erosion?
4. What type of erosion can you observe?
5. Based on all of this information do you believe the formation is a plateau or a fin?

References

1. National Geographic. (2020). Resource Library. Plateau Retrieved from https://www.nationalgeographic.org/

2. Fin (Geology). (2019). Retrieved from https://amp.en.google-info.in/47956556/1/fin-geology.html

3. Herbert, Neal (2020). Geologic Formations. Retrieved April 05, 2021, from https://www.nps.gov/arch/learn/nature/geologicformations.htm