Precambrian – from 4600 million to 542 million years ago
The northern part of the Malvern Hills
The Malvern Hills are composed of igneous rocks, most of which cooled and crystallised deep below the surface. On Broad Down, south and east of British Camp, there were volcanoes which erupted in an island arc which existed more than 600 million years ago. All these rocks have been uplifted by earth movements along a line of weakness in the earth’s crust. Rocks such as diorites, granites, and volcanic lavas can be seen in quarries around the Malverns. To the west are the hills of Herefordshire underlain by Silurian rocks.
Gullet Quarry in the Malvern Hills
This was one of the last working quarries in the area. The hard old Precambrian rock was quarried for road stone.
A piece of Malverns Complex Rock
As the rock cooled from a molten state crystals formed. The slower it cooled, the larger are the crystals. Here pink granite has crystallised in a vein cutting across diorite.
Some uses of Malvern Rock
Malvern rock has been quarried for use as a building stone in local walls and houses. It was also used as road stone.
Severn Valley and Malvern Hills
Precambrian rocks, some of the oldest in Britain, form the Malvern Hills, which rise steeply above the Severn valley to the east, separated from it by a geological fault line, the East Malvern Fault. The Severn Valley is underlain by Triassic mudstones. Beyond that the Cotswold Hills, formed of Jurassic limestone can be seen. In Precambrian times all the land masses on earth were clustered around the south pole forming the continent of Rodinia.