The BGS Lexicon of Named Rock Units — Result Details

Sides Farm Breccia Member

Computer Code: SIFA Preferred Map Code: notEntered
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Unbedded, poorly sorted sheets of pyroclastic breccia, lithic-rich lapilli-tuff; locally pumice-rich. Generally polymict, but with dominant dacite/andesite clasts in places.
Definition of Lower Boundary: At downward change from coarse polymict deposits to welded vitric tuff and lapilli-tuff of the Town End Farm Member. In reference section (RCM3) basal beds include 13m of bedded tuff and lapilli-tuff; and poorly sorted lithic-rich lapilli-tuff.
Definition of Upper Boundary: At sharp upward change in lithology from polymict deposits to welded vitric tuffs of Longlands Farm Member.
Thickness: 68m in type section; 43m in RCF3. Thicknesses are uncorrected for structural dip or borehole deviation from vertical. Thickness in RCM 3 (reference section) not calculated.
Geographical Limits: Sellafield boreholes 5 (NY00SE/30), 8A (NY00SE/38), RCF1 (NY00SE/35), RCF2 (NY00SE/36), RCF3 (NY00SE/37) and RCM3 (NY00SE/39).
Parent Unit: Fleming Hall Tuff Formation (FLH)
Previous Name(s): Sides Farm Member (-2421)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Sellafield Borehole No.5, BGS Registered No. NY00SE/30, 669.18 - 736.95m below Rotary Table Elevation, 583.55 - 651.32m below OD. 
Reference Section  Sellafield Borehole RCM3, BGS Registered No. NY00SE/39. 811.08 - 887.00m below Rotary Table Elevation. This borehole is a deviated vertical one; true depths are not yet known. 
Reference(s):
Akhurst, M C, Chadwick, R A, Holliday, D W, McCormac, M, McMillan, A A, Millward, D, Young, B, Ambrose, K, Auton, C A, Barclay, W J, Barnes, R P, Beddoe-Stephens, B, James, J C W, Johnson, H, Jones, N S, Glover, B W, Hawkins, M P, Kimbell, G S, MacPherson, K A T, Merritt, J W, Milodowski, A E, Riley, N J, Robins, N S, Stone, P and Wingfield, R T R. 1997. The geology of the west Cumbria district. Memoir of the British Geological Survey, Sheets 28, 37 and 47 (England and Wales). 138pp. 
Beddoe-Stephens, B and Millward, D, 2000. Very densely welded, rheomorphic ignimbrites of homogeneous intermediate calc-alkaline composition from the English Lake District. Geological Magazine, Vol.137, 155-173. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable