Logging Requirements
In order to mark this cache as found, please send me a message answering the questions below.
- List the name of this earthcache.
- Name the type of weathering that caused this rock to split.
- In your 'Found It' log, post a photo showing you at the split rock. Logs without photo proof will be deleted.
Un-Webcam
There are a number of webcams at Oak Flat, but one of them is pointed right on the split rock! I wish we could have Webcam Caches again, but until then we can just point out the ones that are out there. To get onto the webcam, climb to the top of the rock and look towards the tower. The webcam updates every 6 minutes and the website stores the caches for some time. As long as you stay on the rock long enough, you could grab the photo online after you get home from your geocaching trip.
Link: Oakflat Webcam #2
The webcam has gone offline. There is still a fire watch webcam at Oak Flat, but it doesn't show the split rock. If this changes, I'll update the cache to provide the right link
The rock at Oak Flat Lookout Tower has been split in two in a spectacular way. The crevice from the split is wide enough to climb into and can be used to get to the top of the rock. As I was exploring the rock, I started to wonder how this rock became the way it is now. I had some ideas while I was there, and then some research afterwards gave me more insight. I recommend exploring this rock from a number of different vantage points to get a feel for how much force mother nature exerted to split it in two!
Weathering
Weathering describes the breaking down or dissolving of rocks and minerals on the surface of the Earth. Water, ice, acids, salts, plants, animals, and changes in temperature are all agents of weathering. Once a rock has been broken down, a process called erosion transports the bits of rock and mineral away. No rock on Earth is hard enough to resist the forces of weathering and erosion.
Mechanical weathering, also called physical weathering and disaggregation, causes rocks to crumble. Some of the types of mechanical weathering are described below.
Cryofactruring - Liquid water can seep into cracks and crevices in rock. If temperatures drop low enough, the water will freeze. When water freezes, it expands. The ice then works as a wedge. It slowly widens the cracks and splits the rock.
Thermal Stress - Changes in temperature cause rock to expand (with heat) and contract (with cold). As this happens over and over again, the structure of the rock weakens. Over time, it crumbles. Eventually, outer layers flake off in thin sheets, a process called exfoliation.
Unloading - When overlying materials are removed, the underlying rocks, released from overlying pressure, can then expand. As the rock surface expands, it becomes vulnerable to fracturing in a process called sheeting.
Swelling - Clay, which is more porous than rock, can absorb and swell with water, weathering the surrounding, harder rock.
Haloclasty - Saltwater sometimes gets into the cracks and pores of rock. If the saltwater evaporates, salt crystals are left behind. As the crystals grow, they put pressure on the rock, slowly breaking it apart.
Plants and Animals - The seed of a tree may sprout in soil that has collected in a cracked rock. As the roots grow, they widen the cracks, eventually breaking the rock into pieces. Over time, trees can break apart even large rocks. Even small plants, such as mosses, can enlarge tiny cracks as they grow. Animals that tunnel underground, such as moles and prairie dogs, also work to break apart rock and soil. Other animals dig and trample rock aboveground, causing rock to slowly crumble.