Rocks, Minerals and Landscapes
Fieldwork: Exploring Metamorphism around a Granite Intrusion
Location: Sinen Gill, north of Threlkeld and Blencathra FSC.
The group traversed a path from above Blencathra to the granite intrusion in Sinen Glen. This took us along a path of the metamorphic aureole, with increasing metamorphism as we moved from the Skiddaw Slate (Ordovician) to the exposed granite. In between there were three stages of metamorphism: Chiastolite Slate (spotted with white chiastolite crystals), Holnfelsed Slate or mudstone with black spots of cordierite, and, closest to the granite, a hardened hornfels with transparent andalusite. To reach the final sites involves a short climb uphill. The granite is best accessed where the stream has eroded into the rock. The metamorphism was caused by heating and pressuring when the granite batholith intruded caused by rising magma. Teachers were able to collect samples of five rock types from sedimentary (with mild metamorphism) to rocks with increasing metamorphism and finally granite.
Background geology to the Lake District, Lake District National Park Authority: http://www.lakedistrict.gov.uk/__data/assets/pdf_file/0008/171188/factsheet_geology.pdf
Cumberland Geological Society (1998) Lakeland Rocks and Landscape: A Field Guide.
Resources
British Geological Survey: Interactive map for viewing geology of the UK, borehole scans, 3D models and a geology app for your phone.
http://www.bgs.ac.uk/discoveringGeology/geologyOfBritain/viewer.html
The Geological Society (offers a summer Geosciences Academy for teachers)
Geology.com: Teaching resources for earth science, including images of rock types and minerals.
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