Wandering along the riverside on our way to get lunch I was having a closer look at the wall and noticed a few things I thought would make an interesting earthcache. The coordinates should place you near the wall, on the river side. Have a look along the base of the section around here.
1) Describe the red sandstone blocks - are they in good condition? Can you see any large grains or pebbles? Are they smooth or rough?
2) Using your answers to question (1) and the information in the description below, do you think these blocks were formed in a high or low energy environment. How might this have contributed to the current condition of the blocks?
3) The blocks near the base of the wall are damaged - is this an example of weathering or erosion? Why do you say that?
4) Take a photo of yourself at GZ, or an identifying item, being careful not to reveal any of the answers to the questions.
If logging as a group, all members of the group must be in the photo - if you don't want to be in the photo, you need to upload your own unique photo showing a personal item or your caching name. The person sending answers must mention in their message the cachers they are sending answers for.
Please submit your answers via message though the Geocaching website or by sending me an email - there is no need to wait for a response before logging your find.
Low-Energy Sandstone Formation
Sandstone in a low-energy environment forms when small sand grains settle in calm water. This can happen in places like deep lakes, the ocean floor, or slow-moving rivers. The water does not have enough force to carry larger pebbles or rocks. Over time, layers of sand build up and get buried by more sediment. Pressure and minerals in the water cement the grains together, turning them into solid rock.
High-Energy Sandstone Formation
In a high-energy environment, sandstone forms from sand and pebbles carried by fast-moving water or strong waves. This happens in places like rivers, beaches, and nearshore ocean areas. The force of the water moves larger rocks and pebbles along with the sand. Pebbles in rivers and beaches are often rounded from constant rolling, while those in fast, short-lived floods may stay rough. When the water slows down, the heavier pebbles settle first, followed by the sand. Over time, the sediments get buried and cemented together, forming a rougher, more uneven sandstone.
Weathering of sandstone
High-energy sandstone is more likely to break down over time because it contains both sand and larger pebbles. The pebbles and the sand may be made of different materials, which weather at different rates. If the cement holding the rock together is weak, water and wind can wear it away quickly. Pebbles can also loosen and fall out, leaving holes that make the rock break apart faster. In cold climates, water can freeze in cracks, expanding and causing pieces of the rock to break off.
Difference Between Weathering and Erosion
Weathering and erosion both break down rocks, but they are not the same process. Weathering happens when rocks break apart or change because of wind, water, temperature changes, or chemicals. It happens in one place and does not involve movement. Erosion is when rock pieces are carried away by water, wind, or ice. Weathering weakens the rock, and erosion moves the broken pieces to new locations.