Malvern Hills - Geology

Geology

The Malvern Hills are formed of some of the most ancient rocks in England, mostly igneous and metamorphic rocks from the late pre-Cambrian, known as the Uriconian, which are around 680 million years old. The Malvern Line or Malvern Lineament is the name applied to a north-south aligned lineament which runs through the Malvern Hills and extends southwards towards Bristol and northwards past Kidderminster. It consists of a series of faults and folds which have the effect of bringing old Malvernian rocks to the surface. Being largely hard igneous rocks, they have resisted erosion better than those of the surrounding countryside and result in a striking line of hills of which the Malvern Hills are the most impressive. This line is considered to mark the edge of two terranes – two once separate fragments of the Earth's crust now joined as one – the Wrekin Terrane to the west and the Charnwood Terrane to the east.

The main face of Gullet Quarry shows a cross-section through the Pre-Cambrian rock and exhibits many rock types including diorite, granite, gneiss, schist, pegmatite and dolerite. The evidence of the complex history of earth movement which formed the Hills can be seen by multiple joints, fractures, faults and shears, which make identifying changes in rock types difficult. Mineral deposits such as haematite, calcite and epidote can be seen within these features.

There is a tiny, man made cave near the ridge of the hills called Clutter's Cave (or Giant's Cave or Waum's Cave, after Walm's Well which is located on the boundary of News Wood below). The cave has been excavated into pillow lavas. Some of the rounded 'pillow' shapes are still visible around the entrance to the cave.