To log a find on this EarthCache you are required to visit the location, gather some information and either message or email the answers to me.
Please feel free to log your find and send your message at the same time.
This is at a river side but there is very little path and to get to the location you will have to cross moorland with no paths
Shale
Shale forms from the pressure of layers of sediment compressing bits of silt that settle into the clay on the bottom of bodies of water. The compressed clay and silt become shale over time. Shale is a sedimentary rock.
Shale starts with bits of rock that erode off of larger rocks from contact with moving water and the weather. Very fine particles of feldspar, quartz, mica, pyrite and other minerals settle to the bottom of still bodies of water, such as swamp lands, deep parts of the ocean and deep, still lakes. The fine rock particles mix with decaying organic matter into a mud. Because weathering is a continual process, new layers are always building up. The top layers press on the bottom layers with more and more pressure. When enough pressure builds up, the bottom layers become rock through a process called lithification. Lithification causes the thin layers that are characteristic of shale.
Shale is a soft rock that breaks easily. The colour varies depending on the exact minerals that formed the shale. Red, green and black are some colour variations. Geologists classify shale as a claystone due to the small size of the particles that form the rock. Shale is a common rock that makes up much of Earth's crust.
If you are looking at shale you will see many, many layers of very thin rock that is broken and crumbled.
Sandstone
Sandstone forms over the course of centuries, as deposits of sand accumulate in rivers, lakes or on the ocean floor, and the sand blends with calcite or quarts and then undergoes compression. As enough time goes by, the pressure pushes all of these elements together to create sandstone. Because not all sand is identical but instead comes in a variety of colours and grain textures, each formation has a unique appearance.
A lot of the structures there are carved out of sandstone because it is a durable rock with consistent structure. Sometimes instead of containing a uniform appearance, though, the weavings of colour make the rock look like they are made of marble cake or marble rye bread.
Some archaeologists have studied the formation of sandstone to determine how different layers of colour ended up in the same sandstone. The most common theory is that a mixture of various sand types split into layers as the sand accumulated centuries or even millions of years ago. A similar process takes place in avalanches as the chaos of movement ensures that no two layers contain the same type of material.
If you find sandstone here you will find it is made of thick layers which are consistent in structure and very durable.
Please message or email the answers to the questions below.
1- Please describe the rock face in front of you, concentrate on the structure and layers of the rock.
2- Is this a shale bed or a sandstone bed, please explain your reasoning
3- How high is the top of the vertical bank above the river bed
Please do not include any photos of the rock face, but if you wish to include other photos that’s fine.
Thanks so much for stopping here and looking at the rocks.
treboR