Computer Code: |
HNG |
Preferred Map Code: |
Hng |
Status Code: |
Full |
Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
Lithological Description: |
Cream and brown-weathered, bedded, fine-grained tuff with accretionary lapilli that forms a widespread distinctive marker unit at the top of the Long Top Tuff Member. |
Definition of Lower Boundary: |
Taken at the base of bedded silicic tuff overlying eutaxitic lapilli-tuff of the Long Top Tuff Member, and lying between 25 and 75m above the base of the member or 5-15m above the top of the Oxendale Tuff where this is present |
Definition of Upper Boundary: |
Defined by the overlying eutaxitic lapilli-tuff of the Crinkle Tuff Member |
Thickness: |
Up to 3m, but is typically less than 1m |
Geographical Limits: |
Cumbria, Thirlmere to Scafell and Langdale in the central Lake District |
Parent Unit: |
Long Top Tuff Member (LTT)
|
Previous Name(s): |
Hanging Stone Tuff Member [Obsolete Name and Code: Use HNG]
(-3475)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Reference Section |
Base Brown, southwest of Seathwaite in Borrowdale, Cumbria Branney et al., 1993 |
Reference(s): |
Branney, M J, Davis, N C, Kokalaar, B P, and McConnell, B J. 1993. The Airy's Bridge Formation in the central Fells. British Geological Survey Technical Report WA/93/41 |
Millward, D, Johnson, E W, Beddoe-Stephens, B, Young, B, Kneller, B C, Lee, M K, Fortey, N J, Allen, P M, Branney, M J, Cooper, D C, Hirons, S, Kokelaar, B P, Marks, R J, McConnell, B J, Merritt, J W, Molyneux, S G, Petterson, M G, Roberts, B, Rundle, C C, Rushton, A W A, Scott, R W, Soper, N J, and Stone, P. 2000. Geology of the Ambleside district. Memoir of the British Geological Survey, England and Wales, Sheet 38. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
none recorded or not applicable |