The BGS Lexicon of Named Rock Units — Result Details

Tranearth Group

Computer Code: TNTH Preferred Map Code: notEntered
Status Code: Full
Age range: Sheinwoodian Age (SS) — Gorstian Age (SG)
Lithological Description: Laminated hemipelagite is the characteristic lithology. In upward succession in the southern Lake District type area: the Brathay Formation consists largely of hemipelagite, the Birk Riggs Formation contains in addition, an abundance of turbidite sandstone, the Coldwell Formation comprises two units of calcareous siltstone separated by hemipelagite, the Wray Castle Formation comprises hemipelagite with some turbidite siltstone.
Definition of Lower Boundary: As for the base of the Brathay Formation: conformably overlies the grey siltstone of the Browgill Formation (Stockdale Group).
Definition of Upper Boundary: Conformably overlain by turbidite sandstone at the base of the Coniston Group.
Thickness: About 500 to 1000m
Geographical Limits: Northwest England: Southern Lake District, Cumbria; Howgill Fells, Cumbria inlier, Cumbria; Craven inliers, Yorkshire.
Parent Unit: Windermere Supergroup (WIN)
Previous Name(s): Windermere Group (-2491)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Southern Lake District, Cumbria. All constituent formations have individually defined type sections. Kneller, Scott, Johnson and Allen, 1994. 
Reference(s):
Rickards R B and Woodcock, N H. 2005. Stratigraphical revision of the Windermere Supergroup (Late Ordovician-Silurian) in the southern Howgill Fells, northwest England. Proceedings of the Yorkshire Geological Society, Vol 55. 263-285. 
Arthurton, R S, Johnson, E W and Mundy, D J C. 1988. Geology of the country around Settle. Memoir of the British Geological Survey, Sheet 60 (England and Wales). 
Johnson, E W, Soper, N J, Burgess, I C, Ball, D F, Beddoe-Stephens, B, Carruthers, R M, Fortey, N J, Hirons, S, Merritt, J W, Millward, D, Roberts, B, Walker, A B and Young, B. 2001. Geology of the country around Ulverston. Memoir of the British Geological Survey, England and Wales, Sheet 48. 
Kneller, B C, Scott R W, Soper N J, Johnson E W and Allen P M, 1994. Lithostratigraphy of the Windermere Supergroup, Northern England. Geological Journal, Vol. 29, 219-240. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E030 E038 E039 E048 E050 E060