Tafoni, Weathering, and Erosion

There is plenty of parking at Ground Zero to pull completely off the road. You can make your observations from this location as you view the cliff across the street to the NW.

This is an earthcache which will provide you with an educational experience about a feature on our planet. There is no physical container for you to find. Your visit here will be a fact gathering trip to answer the questions below. You must email us with the answers to the questions in order to log this cache as found.

TYPES OF ROCKS

The world has three types of rocks: Igneous, Sedimentary, and Metamorphic.

Sedimentary rocks are formed by the accumulation of small to large particles derived from all 3 types of rocks and in some cases, organic material and then undergoes compaction, cementation, or evaporation. These particles are deposited at the earth's surface and within bodies of water while being transported by the wind, water, ice, mass movement, and glaciers. There are three classifications of sedimentary rocks: organic, clastic, and non-clastic. Examples of organic sedimentary rocks are coal and limestone, while examples of clastic include shale and conglomerate. Non-clastic includes rock gypsum and rock salt.

TAFONI

Tafoni are small cave like formations found in granular rock such as sandstone, granite, or sandy limestone. They have rounded entrances and smooth concave walls. Often they are connected or found in clusters (looking like the surface of a sponge) along vertical hillsides, cliffs, or other rock formations. Other names for Tafoni are honeycomb weathering, stonelace, stone lattice, and fretting. Although the formation of Tafoni are not totally understood, one explanation is thru cementation, which is the binding together of particles. Water from dew or precipitation reacts with the "cement" holding the rock grains together and gets into tiny fractures around the particles. Some are hardened, while others are loosened, causing the mini caves. Wind does the rest of the weathering.

WEATHERING

Weathering is the mechanical and chemical hammer that breaks down and sculpts the rocks. Erosion transports the fragments away. The four main types of weathering are: freeze-thaw, onion skin, chemical, and biological.

*Freeze-thaw is when water seeps into cracks and freezes it so then it expands. This powerful force can increase the size of cracks. Over time the repeated freeze-thaw action of water can break rocks apart.

*Onion skin weathering is common in warm areas. The sun shines on rocks during the day causing them to expand with the warmth. At night the cooler temperatures contracts the rock. Overtime this continued process causes small pieces to flake off.

*Chemical weathering causes an alteration to the chemical composition of rock due to a reaction. Water that is slightly acidic can dissolve rock. An example would be acidic rain from pollution changing the chemical composition of limestone and gradually wearing it down.

*Biological weathering is the effect of living things on rocks. One example would be when a tree root extends into the ground and breaks rocks by lifting them up. Ivy growing on a wall can cause bricks to loosen. Even lichen and moss can effect rocks and biologically break them down.

EROSION

Once the rock has been weakened and broken up by weathering, it's ready for Erosion. Erosion happens when rocks and sediments are picked up and moved to another place by ice, water, wind, or gravity. TALUS is the rock debris at the base of a cliff

REFERENCES

Wikipedia

LOGGING REQUIREMENTS

To demonstrate the educational value of this cache, please answer the following questions. Submit the answers to these questions by messaging us through our profile page or at the following email: nukemator@gmail.com Do not post your answers with your log. Photos are optional, but appreciated and encouraged

SADLY, DUE TO PREVIOUS EXPERIENCE WITH CACHERS WE HAVE HAD TO INSTILL SOME NEW RULES REGARDING OUR EARTHCACHES. PLEASE DO NOT LOG THIS EARTHCACHE AS FOUND, UNTIL AFTER YOU EMAIL THE ANSWERS TO THE CACHE PAGE QUESTIONS. YOU MAY LOG THE CACHE AS FOUND AFTER THE ANSWERS ARE SENT, WITHOUT WAITING FOR OUR RESPONSE. EACH LOGGING CACHER (CHILDREN'S FOUND LOGS JUST NEED TO REFERENCE THEIR PARENT'S ANSWERS) MUST EMAIL THEIR OWN ANSWERS WITH THEIR FOUND LOG. LOGS THAT DO NOT FOLLOW THESE GUIDELINES WILL BE DELETED WITHOUT NOTIFICATION. IF YOUR LOG IS DELETED, YOU MAY RE-LOG THE CACHE AFTER YOU SEND THE ANSWERS TO US.

******Please include your geocaching name and the number of people in your group with your email and answers******

1. In your estimation, how tall is the cliff across the street where the Tafoni are located?

2. After making your observations describe in your own words the Tafoni. Are they in clusters, lines, or placed singularly? What is the size of largest one and the smallest one? What shapes of tafoni do you see?

3. Do you see evidence of any other type of weathering based on the above text? Explain what types of weathering are present and please give examples of what you saw.

4. How about evidence of erosion? Please tell us what evidence you saw if any. Do you see any Talus