Welcome to Selwicks bay, Flamborough head, a headland on the Holderness coastline, the fastest eroding coastline in Europe
In the other nearby earthcaches, features of erosion are discussed. In this earthcache, I will provide you with a unique earth science lesson about the way rocks collapse and what happens to them after that.
SAFETY
Please only attempt this when the tide it out. This is not for the purpose of the earthcache but merely for your safety. There is a strong undercurrent which can pull people to sea or knock you over. Please don't approach the seals. Also, do not stand too close to the cliffs. We will learn why today. I do not take responsibililty for your safety at this point. Other than that it is relatively safe so have a good time!
Today, we will be talking about Mass Movement and Transportation
What is Mass Movement? Mass Movement is the downhill movement of weathered material under the force of gravity. They mostly happen on cliffs, such as the ones around you. Different types of weathering cause this. Take a look at my or other earthcaches for more information on this.There are 4 main types of Mass Movement.
Rockfall - The movement of rocks down a slope at a 90 degree angle. You many know it as a rock avalanche where rocks fall off the cliff
Landslide - The movement of rocks down a slope. Basically rockfall but on a less steeper slope. Rocks will slide or roll down instead of fall.
Mudflow - The movement of supported saturated soil (mud) down a slope. You may know this as a mud avalanche.
Slumping - The movement of saturated soil (mud) down a slope. The key difference between this and mudflow is that here, the mud beneath is unsupported and creates almost layers on the way down
But what happens after that? The rock won't just stay there. It will get washed away by the tide into the sea. But then what? Here is where transportation will come in play. There are 4 main stages:
Traction - Where larger rocks are rolled along the sea floor by the force of the current. This creates a type of erosion called abrasion. This is Where the rock scrapes against the sea floor. As it gets smaller it goes into Saltation
Saltation - Where smaller rocks or larger pebbles bounce along the sea floor and are moved by the current. This creates a types of erosion called atrrition. This is where rocks hit against each other. as it gets smaller, Suspension comes into play.
Suspension - Where small pebbles are carried by the force of the current. These get smaller due to the force of the water (hydraulic action)
Solution - Where the rocks/pebbles dissolve in the water
These rocks normally get deposited at nearby beaches at suspension or solution.
QUESTIONS :
In order to claim a find, you must send me the answers, either by the messaging facility or by email.
1) What types of mass movement event would take place at the published coordinates?
2)Grab a few pebbles of different sizes. Go up to the water and have a play around with them moving them. Please tell me how wide your pebbles are and what transportation process they would be affected by. The transportation methods are listed above
See the hint for extra clues on answering questions
Enjoy 
*Thanks to the Yorkshire Wildlife Trust for allowing me to place an earthcache here because this area is an SSSI (Site of Special scientific interest)