The war memorial in Thornton Rust is a plaque on the wall of the Village Institute. You will need to lookupwards.ย
The geology of the local area is from the Yoredale Series, a time in the Carboniferous Period, when varying environments lead to different rocks being deposited.ย These being sandstone, limestone and siltstone, though we are looking at different type of rock, and igneous rock, more specifically granite.ย
๐ณย Igneous rock.ย
Igneous rock is formed through the cooling and solidification of magma or lava. Igneous rock forms byย crystallisation either below the surface as intrusive (plutonic) rocks or on the surface asย extrusive (volcanic) rocks.ย
Granite is formed of crystals of different minerals which together form the rock. These minerals are quartz, mica and feldspar.ย ย
Quartz. This is a clear or greyish mineral, and is the most common mineral found on the surface of the earth.
Mica. This is a black or sivery mineral, which look like flakes.ย
Feldspar. This comes in a range of colours. Pink or white feldspar is known as as orthoclase, whilst grey is known as plagioclase. The pink colour, comes from K-Spar, which is also known as potassium feldspar.ย
Examinjngย granite can give an indication as to how quickly or how slow the rock formed. This is done by looking at the crystals which form the rock.ย
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Crystals which have well defined appearance are known as Euhedral.ย Crystals which are not well defined or who don't have any apparent structure areย known as anhedral.ย
Granite can be coarse grained, and also fine grained. To be defined as coarse grained means you should be able to see individual crystals, whilst fine grained means the opposite, whilst they are there, they are difficult to discern by the naked eye.ย
The rate of cooling of the magma, and thus formation of the granite affects whether there is a coarse or fine texture.ย ย
๐ด Slow cooling.
Slow cooling of the magma allows for larger crystals to form, thus giving a coarse texture.ย
๐ด Fast cooling.
Fast cooling leads to smaller crystals and thus a fine texture.ย ย
๐ด Mixed rate of cooling.
The magma may cool at different rates, and this will lead to a variation in the texture of the granite, with both coarse and fine textures present.
This being an EarthCache, in order to log it, I ask that you complete the aboveย tasks. Please send the answersย to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile.
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1. Please describe the texture of the granite, is it coarse or fine?
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2. Would you say it is euhedral or anhedral?
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3. At what rate would you say the granite cooled?ย
โIf anybody would like to expand to this series please do, I would just ask that you could let Just-Us-Two know first at justustwo1013@gmail.com so they can keep track of the memorial numbers and names to avoid any duplication.