The BGS Lexicon of Named Rock Units — Result Details

Harthwaite Tuff Formation

Computer Code: HAWT Preferred Map Code: Hawt
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Bedded volcaniclastic siltstones and sandstones with intercalated silicic crystal and vitric tuffs
Definition of Lower Boundary: Taken at the base of the sequence of bedded volcaniclastic rocks resting on densely welded rhyolitic tuff of the Knock Pike Tuff Formation. The basal beds contain fragments of the underlying Knock Pike Tuff
Definition of Upper Boundary: Defined by the base of the unconfomably overlying sedimentary rocks of the Dufton Shale Formation
Thickness: About 300m
Geographical Limits: Restricted to the Cross Fell Inlier, Cumbria
Parent Unit: Borrowdale Volcanic Group (BVG)
Previous Name(s): Harthwaite Formation (-3456)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Harthwaite Sike, Cross Fell, Cumbria Burgess and Holliday, 1979 
Reference Section  Small quarry on Dod Hill, Cross Fell, Cumbria Burgess and Holliday, 1979 
Reference(s):
Burgess, I C and Holliday, D W. 1979. Geology of the country around Brough-under-Stainmore. Memoir for 1:50 000 geological sheet 31 and parts of sheets 25 and 30. Geological Survey of Great Britain (England and Wales). [London: HMSO.] 131pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E024 E030 E031