Please note: Due to the challenges associated with ensuring that everyone has visited GZ, group responses will not be accepted. Individuals must submit their own responses and photos. Thank you.
Shap Granite is Devonian in age (417 to 354 million years old) and is still periodically quarried near Shap, Cumbria (in the North of England). It is a very distinctive granite used for decorative work, often with a polished finish. Shap is rich in feldspar, mica and quartz but has very distinctive large porphyritic crystals of pink orthoclase feldspar which can be up to 5 or 6 cm in length; occasionally xenoliths are also present. Xenoliths are a piece of rock within an igneous rock that is not derived from the original magma but has been introduced from elsewhere, especially the surrounding country rock.
Two varieties of Shap exist, dark Shap which is brownish red with black and grey colouration, and light Shap which is mainly pink and grey. The mineralogy of this granite is relatively simple - biotite (black), quartz (colourless --> many colours --> black) and two feldspars (plagioclase (white, grey, bluish-white) and K-feldspar (pink)). These are considered the "rock-forming" minerals. Accessory minerals such as fluorapatite (sea-green, violet, purple, blue, pink, yellow, brown, white, colourless), ilmenite (Iron-black; grey with a brownish tint in reflected light) and titanite (black, green, grey, yellow, brown) are also present in minor amounts.
Source: http://www.stonedatabase.com/stone_types.cfm?stc=125
Source: https://www.virtualmicroscope.org/content/granite-shap
Questions - please answer all questions based on what is seen at GZ. I read and respond to all answers submitted, and will confirm responses. If you believe there will be a delay in submitting your answers, then kindly post a note until you are able to have your answers confirmed.
The nature of an Earthcache is to get you on-site and learning something (new). If answers are missing, incorrect and/or appear to be "armchair" responses, I will delete any posted finds. Group responses will not be accepted. Individuals must submit their own responses and photos. Thanks for visiting!
1. Is the is an example of light or dark Shap and why?
2. What colour is predominant in the Shap at GZ and identify its mineral composition based on the information provided above. Provide an approximate % for each mineral observed at GZ.
3. Based on your observations and the information provided, are xenoliths present in the rock? Explain why or why not. Provide examples (describe) what you see.
4. Using your knowledge and observation of GZ, why do you think Shap was selected for this particular location?
5. Post with your log a photo of yourself/your caching name in front of the "Valumart lemons" photo wall (outside of the building).