Principle of Original Horizontality at Oak Mt. SP EarthCache

Principle of Original Horizontality at Oak Mt. SP - Earthcache

This Earthcache is meant to be wheel-chair accessible. 

Stand on the bridge at GZ, face NE, look over the stonework of the bridge, and observe the layers of rocks in the creek bed below.  Please answer the questions below from your observations of the rocks in the creek bed and from the reading below.

This is an Earthcache and as such is a kind of virtual cache in that there is no physical container to find and log to sign.  You must answer the questions below and then email or message the correct answers to Papa Bear 204.  Any “Found Log” that is not accompanied with an email with the answers will regrettably be deleted. 

Questions for Logging Credit:

1. Are the rocks in the creek?  A.  Folded   B.  Tilted   C.  Arched    D.  Crushed

2.  Estimate the angle from horizontal that the rocks are laying.

3.  How many distinct lays of rock can be seen in the creek,

4. What Geology Principle best describes how the material that formed these rocks were originally deposited. 

5. From you answer in question #4,  what has happened to these rocks since they were originally formed?

Optional:  Post a pic of you (and your group) at the bridge.  Do not take pictures of the rocks in the creek as I will ask you to delete them. 

Educational Reading:

In geology, The Principle of Original Horizontality states that layers of sediment are originally deposited horizontally under the action of gravity.   The principle is important to the analysis of folded and tilted strata that we see on the surface of the earth’s crust and especially in the Birmingham, Alabama area.  The earth’s great dynamic internal forces and resulting plate tectonics cause movement and collisions of large plates of the Earth's crust.  The collisions of these plates result in rock strata being folded, tilted, broken, uplifted, and subducted.    The rocks that you see here were originally formed from horizontal deposits of sand that formed sandstone.   The Earth’s dynamic forces that formed the mountains in the Birmingham area then caused these rocks to be altered to their present position.  These rocks were at some time in the distant past horizontally laying unbroken sandstone.  Earth’s great dynamic forces exerted great force on these rocks these rock that caused them to be altered to their present position. Erosion is now gradually tearing them down and gravity is working to deposit the sand again horizontally somewhere else.