You will need to visit the location given where there is plenty of parking.
Please read the information below and before you claim a find send me answers to the questions below, either by message or email.
You are invited to send your answers and log a find at the same time.
I read all logs and will respond within a few days of your submission.
EarthCache information
For this cache I’d like you to turn your attention to the rocks which line the parking spaces
You will be asked questions about the way this stone was formed and why they look like they do.
Sedimentary rocks
Sedimentary rocks are formed from the broken remains of other rocks that are moved to another location, usually by water or wind and become joined together to form new deposits.
A river or wind carries, washes or transports, pieces of broken rock as it flows or blows along. The faster the river or wind the more the small pieces it can carry. When the river reaches a lake or the sea the flow of water slows, its load of transported rocks settles to the bottom. When winds slows it will start to drop its cargo of stone particles. We say that the rocks are deposited as the small particles settle to the bottom. The deposited rocks build up in layers, called sediments. This process is called sedimentation.
The weight of the sediments on top squashes the sediments at the bottom. This is called compaction. The pressure of weight from above means the water and air is squeezed out from between the pieces of rock and crystals of different salts form. The crystals stick the pieces of rock together. This process is called cementation.
Cementation occurs as the minerals and crystals from each layer form a layer. If the layer of sedimental material is constant it is less likely a distinct layer of different sediment will form. The more often the change in make-up of the minerals deposited changes, the more likely some the cementation is to be of a different structure to the other layers forming many thin week layers.
These processes eventually make a type of rock called sedimentary rock. It may take millions of years for sedimentary rocks to form. The thickness of the resulting rock sediments can vary from a few millimetres to several meters of each layer.
In most rock formations the bedding planes in sandstone will be parallel and will be easy to spot. Most of the time the bedding planes are even still parallel with the ground. Most sandstone was laid down with regular deposits and a constant flow of new and undisturbed deposits. This results in the type of rock we use in building using stone.
However this might not be the only story as rock is being formed. As the deposits build up the rock will become harder and harder but there will be a time when it’s not quite hard but no longer liquid either. If the rock is disturbed during this period (which might be thousands of years) the bedding planes may be disturbed. Bedding panes are lines in the construction of sandstone which indicate a change in the material laid down.
If pressure is exerted on the forming rock, say from the side caused by an earthquake, a horizontal bedding plane with be disturbed. To illustrate this try placing 10 sheets of paper on top of each other and then push the ends together, if you do this on a table you will get an anticline.
Anticlines form an 'A' shape in rocks. They are folds where the apex points up, toward the sky. Generally, they fold where the oldest rocks form the core of the fold. A syncline is the exact opposite for an anticline, it forms a ‘U’ shape bend in the rock and the oldest rock will normally be outside of the bend. Both are created when pressure from the side as rock pile up like sheets of paper are pushed together.
If this happens time and time again as rock is forming the resultant rock will be very confused. It may be difficult to find any bedding panes at all and what you do find will be in small sections and at different angles to the bedding planes close by.
So when you look at this rock you need to decide if it was laid down like most stone with little disturbance or did it get disturbed during its formation.
Please answer the questions below
- Please describe the make-up of the rock, please concentrate on how the size of rocks and pebbles and bedding planes
- Please tell me how you think the rock came to look like it does and explain your thinking.
- Please tell me how many rocks there are lining the road.
Thanks for visiting the location
treboR