Welcome to the Vale of Pickering in North Yorkshire.
How to log this EarthCache
In order to log your find, please provide the answers to the below questions. The answers can be found by visiting the listed coordinates which is the outside wall of the train station, reading the below description, and taking observations in the field.
- Look at the main wall of the station building from the outside. Find some ringed or banded formations in the rock. Describe the ones you have found, in terms of colour, shape and size.
- How do you think these rings were formed?
- Look again at the wall and this time find some spherical, circular or oval deposits. Describe the colour of these deposits, and from this try to identify the mineral that these are formed from.
- Are these deposits scattered throughout the rock, or arranged in layers? Why do you think this is?
You may optionally want to upload photos of your visit, of course I would love to see them! I will respond to your answers as soon as I can.
The Vale of Pickering
The Vale of Pickering is a low-lying flat area of land in North Yorkshire, England, and is roughly extends from here in Pickering in the North to Malton in the South, and from Helmsley in the West to Scarborough in the East. The landscape is rural with scattered villages and small market towns, like Pickering where this cache is located.
The Vale of Pickering is a drainage basin for the surrounding hills. There used to be a post-glacial lake here called Lake Pickering. Following the last glaciation Lake Pickering gradually drained away leaving a complex of rivers and marshes which humans have gradually tamed.
Geological Precipitation
Patterns in sandstone, e.g. bands or streaks, are typically the result of the movement/deposition of minerals. This process is known as precipitation. Over time, water moves through the sandstone, because sedimentary rocks are usually porous and permeable. This water often carries dissolved minerals from the surrounding environment or from within the rock itself.
Chemical Weathering
A process called chemical weathering may cause the colour of rocks to change. For example, rocks containing iron impurities tend to rust when they come into contact with oxygen or water. When they begin to rust, they turn reddish-brown. Copper impurities can cause the rocks to turn green, because copper oxide is this colour (think of the Statue of Liberty).
Mineral Compounds and Ores
Many sandstones contain small amounts of mineral compounds. These can have the appearance of differently coloured and textured deposits or nodules within otherwise uniform rocks. These minerals can be dispersed throughout the rock or may be occur in a specific layer. They might occur in a particular layer if they were laid down in only one event, such as a flood. If the sediment has been mixed in some way before the rock formed, they may be more uniformly scattered.
Where the minerals are valuable, they are known as ore and are in some areas mined. Examples include hematite (red coloured; containing iron), galena (silver coloured; containing lead) or native metals (such as gold).