Published online by Cambridge University Press: 01 May 2009
A large basic sill intrudes the Shineton shale (Cambrian) at Maddocks Hill, east of the Wrekin, near Wellington, Shropshire. An old quarry exposes the contact and reveals that the shale close by has been recrystallized to a hard, compact hornfels, the intensity of alteration decreasing away from the contact. Thin sections show that the metamorphic effect was solely thermal, the rock having been completely recrystallized, and biotite having been generated under conditions of the amphibolite facies. The metamorphism is compared with that brought about by other basic hypabyssal intrusions.