Yorkstone
Yorkstone is a type of tight grained sandstone which, which has been quarried specifically from a quarries in Yorkshire. Sandstone is usually composed of feldspar or of quartz, which are the most common minerals in the earths crust. Sandstone can appear in multiple different colours, however Yorkstone tends to be to light blue grey or brown in colour. Yorkstone as a building material has many uses, but is most commonly used for paving.
Portland Stone
Portland Stone is a type of limestone which is quarried from the Isle of Portland. Limestone is usually composed of calcite or of aragonite, which are both crystal forms of calcium carbonate. Portland stone was formed as the bed of a warm shallow sea, most likely close to land. As the sea is warmed, carbon dioxide is released which allows calcium and bicarbonate ions within the water to combine into calcium carbonate, or calcite. The calcite forms a type of mud on the sea bed. Tiny shell fragments falling to the sea bed will then become coated in this mud over time, forming small balls. Over time, these balls of mud become cemented together by further calcite to become Portland Stone. Portland Stone is cemented together enough to resist weathering, but is not so cemented that it becomes a difficult stone to work into sculptures, or blocks for building.
Aberdeen Granite
Aberdeen Granite is a type of fine grey granite which is quarried in the north east of the United Kingdom. Granite is usually composed of quartz and alkali feldspar, but the properties and colouration can vary greatly due to the inclusion of other minerals. Granite is a hard stone which can be used for a number of uses, including memorials, paving and building blocks. Granite is however, very difficult to carve using hand tools.
Location
At the location, there are a number of carved stone benches. The coordinates are for the only bench on the south side of the road, which I found the easiest to examine, but the others should also be suitable to complete this EarthCache. To complete this EarthCache, please provide answers to the following question via email or via the Message Centre.
Questions
1. Describe the rock which has been used to create the bench. Describe the colour, grain and texture of the rock.
2. What type of rock is this?
3. Can any fossils be seen in the rock? How big are they? What shape are they? What creatures could they have been?
4. Are there any fossils present which are given a specific name by stone masons?
5. Is the rock sedimentary, metamorphic or igneous?
6. How would the presence of fossils support your answer to the previous question?
Optionally, please take a photograph of yourself, or your GPS near one of the benches and post it with your log. This will help to prove your visit, but is not compulsory.
Please feel free to log without receiving a reply. I will endeavour to send a reply ASAP to confirm your answers. Logs without a supporting email will be deleted.
Hopefully, you will have fun and learn something new whilst completing this EarthCache. I look forward to reading your answers and your logs.