Ray and Crinkle Crags

Also within

Cumbria County LAKE DISTRICT National Park

Condition (Natural England)

Geology & landscape

Geological Period: Ordovician · Rock Type: Basalt

Landscape processes: Volcanic / Igneous

Birds & fish recorded

Fish

Description

Description Ray and Crinkle Crags lies above the great southern Lake District. The site rises to 859 Crinkle Crags and forms an extensive area of land. Rock outcrops at the site provide criticalof volcanic activity during the early stages of Group of Ordovician age. Langdale Valley in them OD at the summit of high crags, gills and fell evidence on the character the Borrowdale Volcanic Ray Crag is the type locality for the Ling cove Formation of the Borrowdale Volcanic Group. Outcrops here expose effusive products of the early stages of development of the volcanic pile and these are chiefly of basic composition. Excellent exposures of subaerial pahoehoe, aa, and blocky basalt lavas are all present. Outcrops in the vicinity of Stonesty Pike provide the best exposures of the Whorneyside Tuff formation in its type area. The Formation is divided into two, a lower ignimbrite the Whorneyside Lapilli Tuff and an upper sequence of bedded tuffs the Whorneyside Bedded Tuff. Thissequence represents the first major explosive produces in the Borrowdale Volcanic Group following the effusive dominated lower part of the succession. It is an important stratigraphical marker horizon. The bedded tuffs are considered to result from a subaerial phreato plinian eruption, a type not seen elsewhere in the British Isles. Extensive softsedimentation deformation structures in the bedded tuffs testify to considerable seismic activity and block faulting following upon the eruption and emplacement of the tuffs. This disturbance has been linked to the evacuation of a major magma chamber, the contents of which are now represented by the lower ignimbrite unit.