The BGS Lexicon of Named Rock Units — Result Details

Aber Mawr Formation

Computer Code: ABMR Preferred Map Code: notEntered
Status Code: Full
Age range: Arenig Series (OR) — Arenig Series (OR)
Lithological Description: Dark, laminated graptolitic mudstones, with interbedded rhyolitic turbiditic tuffs and debrites.
Definition of Lower Boundary: Not seen.
Definition of Upper Boundary: Conformably overlain by the Porth Lauog Formation, the boundary being taken at the first debrite incutsion into the black mudstones.
Thickness: More than 215m
Geographical Limits: Ramsey Island, Pembrokeshire.
Parent Unit: Not Applicable (-)
Previous Name(s): Aber Mawr Beds (-3785)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Aber Mawr Bay, Ramsey Island. Kokelaar et al, 1985. 
Reference(s):
Kokelaar, B P, Bevins, R E and Roach, R A. 1985. Submarine silicic volcanism and associated sedimentary and tectonic processes, Ramsey Island, south west Wales. Journal of the Geological Society of London, Vol.142 (4-6), 591-617. 
Pringle, J. 1930. The geology of Ramsey Island (Pembrokeshire). Proceedings of the Geologists' Association, Vol.41, 1-31. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E209