The BGS Lexicon of Named Rock Units — Result Details

Hackley Limestone Member

Computer Code: HKYL Preferred Map Code: notEntered
Status Code: Full
Age range: Lochkovian Age (DO) — Pragian Age (DP)
Lithological Description: Mature, massive, rubbly fossil soil carbonate (calcrete) up to over 5 m thick, with concretions up to 0.3 m across, lying 350 to 400 m above the base of the St Maughans Formation.
Definition of Lower Boundary: At base of limestone, or of lower of two limestones where the bed is split into two, where it overlies red mudstones of the St Maughans Formation.
Definition of Upper Boundary: At top of limestone or of higher of two limestones where the bed is split into two, where it is overlain by mudstones or sandstones of the St Maughans Formation.
Thickness: Locally over 5 m.
Geographical Limits: Several kilometres on the eastern limb of the Bredenbury Anticline, south-west and north-west of Bromyard, Herefordshire; also probably on western limb of fold at Crowels Ash [S0 622 525].
Parent Unit: Freshwater West Formation (FWW)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Disused quarry near Hackley Farm, Herefordshire [SO 636 534]. Brandon, 1989. 
Reference(s):
Brandon, A. 1989. Geology of the country between Hereford and Leominster. Memoir for 1:50 000 Geological Sheet 198. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E198