This earthcache will provide you with an educational experience about a geological feature on our planet. There is no physical container for you to find here. Combined with the information in the description and your observations at the posted coordinates, you will be able to answer the logging tasks below.
Logging Requirements and Tasks
Read the lesson below, visit the location, answer the following questions and send the answers to me via my Geocaching Profile.
1. In your own words, describe what exfoliation is.
2. Choose one of the three processes that cause exfoliation and describe how it happens.
3. At the posted coordinates, observe/examine the target rock (granodiorite) and describe the examples of exfoliation that you see.
Required in your log, upload a photo of you, the group you attended with or a personal item the subject of this earthcache in the background. If your answers are profoundly off, I will contact you. Otherwise, please log your find after sending me your answers. With your answers, please include the names of other geocachers with you. Logs without accompanying answers sent or without a photo uploaded may be deleted without notice. Sending the answers is a requirement not a request. Please note, answering the logging tasks is based on your observations at the site and content from the cache page, there is no need to do any further research to complete the logging tasks. If asked to give an answer in your own words, please do that, do not regurgitate a definition or information that may already be given on the cache page, you will not learn otherwise.
Geology
In geology, exfoliation is a type of physical weathering where outer layers or sheets of rock peel away from a larger rock mass, often due to temperature fluctuations, pressure release, or moisture variations.
Here's a more detailed explanation:
• What is it? :
Exfoliation, also known as "sheeting" or "onion skin weathering", is a process where thin, curved, or flat layers of rock detach from a larger rock mass.
• How it happens :
Pressure Release: Exposed igneous rocks break apart in a process called exfoliation. As plutons that formed deep within the Earth are brought to the surface through erosion or uplift,the outer layers are released from the pressure on them. in response to this pressure release, the minerals expand and separate from the under;ying rock in a concentric or dome pattern. This pressure release allows the rock to expand, creating cracks and fractures parallel to the surface, leading to exfoliation. See picture in Gallery.
Temperature Changes: Repeated heating and cooling can cause the outer layers of rocks to expand and contract, leading to stress and eventual fracturing and peeling off.
Moisture Variations: Wet-dry cycles can also contribute to exfoliation, as water can seep into cracks and expand when it freezes, further fracturing the rock. This type of exfoliation is most common in colder climate locations. It usually take a few cycles of freezing and thawing before breaking a piece from the host rock.
Examples:
• Exfoliation domes: The rounded, dome-shaped hills or mountains formed by exfoliation are a classic example.
• Granite: Granite, a common igneous rock, is particularly susceptible to exfoliation.
• Yosemite National Park: Half Dome in Yosemite National Park is a well-known example of a rock formation showcasing exfoliation.
• Significance: Exfoliation is a key process in shaping landscapes and plays a role in the weathering and erosion of rocks over time.