Caution:
Parking can be found on the westbound side of the road (see provided coordinates) Please ensure you pull completely off the pavement. There is no need to cross the road! Please be aware of your surroundings.
Logging requirements:
Please do not post answers in your log.
Please message me with answers to the following questions. *The photo requirement at the cache location is required!* Once you have sent me your answers, go ahead and log your find, no need to wait for a response. If you are caching as a group, each person claiming the find needs to send answers.
Failure to meet the logging requirements may result in removal of your log.
Questions:
- Do you see evidence of iron oxide in this formation?
- Describe how the layers appear here at this Monterey Formation. (Are they relatively horizontal or do they change directions? Are the layers relatively uniform or do they vary in width?)
- Compare your description in question 2 to the Mars rover photo. What similarities and differences in the Martian formation do you see?
- What do you think could play a factor on the shape and size of these layers in both locations?
- Based on the information you have learned, do you believe this could indicate a previous presence of water on Mars? Why or why not?
- *Take a photo at this location and attach it to your log or send it to me in a message.* Yourself, a thumbs up, a personal item, a piece of paper with your username on it, etc. Any will do, just something distinctive that proves you went to this location needs to accompany your answers/log.
The Cache:
Rising up before you is the subject of this EarthCache, a roadcut made of shale that is part of an aptly-named Monterey Formation. These sedimentary formations were created during the Miocene Epoch (23 million-5.3 million years ago), when this entire are was underwater. For reference, this spot is approximately 450ft (137m) above sea level.
What is shale?
Shale is sedimentary rock formed over long periods of time as silt, clay, mud, and other materials settle at a location, often transported by water. Eventually, the material begins to compact as more pressure builds above it such as more sediment or water pressure. Shale is often composed of many layers and can reach several meters thick. Each layer, however, is usually relatively thin and fissile (easily breaks apart). Organisms would also become trapped in these layers, some leaving behind fossils while others eventually became what we know as petroleum, creating what is known as "oil shale".
Monterey Formations can be found throughout California and many contain an abundance of former aquatic plants and microorganisms that eventually turned into petroleum, so much so that Monterey Formations are the major source of California's crude oil production. These formations are also rich in silica, making it stronger than other shales and preferable for the use in building materials. Some other materials that may be found are quartz, calcium carbonate, and iron oxide (the same thing that gives Mars it's distinctive rusty color).
Mars:
Compare the the formation in front of you to this photo of Martian shale at the Gale Crater taken by the Curiosity Rover in 2012. Take note of the scale:
Sources:
https://geology.com/stories/13/rocks-on-mars/
https://www.britannica.com/science/shale
https://www.csulb.edu/geological-sciences/monterey-formation-of-california
https://www.britannica.com/science/Miocene-Epoch
https://pubs.usgs.gov/pp/0212/report.pdf
*Congrats to Tootsie.22 on FTF!*
