West Cornwall - Geology
Cordierite - Hornfels / Botallack (S17)
Large Knotted Porphyroblasts of Cordierite ( a dark mineral formed from metamorphic mudstone )
in the northern headland of Zawn A Bal (Mine Cleft).
A track leads down towards this area and gives an excellent view of Crowns Engine Houses.
Hornfels are formed by contact metamorphism - baked and recrystallised by the heat of Igneous Intrusion.
Some minerals tend to form Porphyroblasts with a knotted texture.
-------------------------------------
Botallack is between Pendeen and Cape Cornwall in Gallery 17
Ref: 4498.9
Date: 25/01/2017
Location: SW 3620 3333