The BGS Lexicon of Named Rock Units — Result Details

Penmynydd Formation

Computer Code: PENMY Preferred Map Code: notEntered
Status Code: Full
Age range: Ediacaran Period (AD) — Ediacaran Period (AD)
Lithological Description: Strongly schistose semipelite and subsidiary psammite, interlayered with lenticular units of crossite and lawsonite-bearing metamafic rock (blueschist / glaucophane schist) and lenticular units of green amphibole-bearing metamafic rock.
Definition of Lower Boundary: Tectonic contact.
Definition of Upper Boundary: Tectonic contact - thrust with Pen-y-Parc Formation (PENYP). In part unconformably overlain by Ordovician rocks, e.g. Llyn Alaw Group (ALAW).
Thickness: none recorded or not applicable
Geographical Limits: Anglesey.
Parent Unit: Not Applicable (-)
Previous Name(s): Central Anglesey Shear Zone (CASZ)
Alternative Name(s): none recorded or not applicable
none recorded or not applicable
none recorded or not applicable
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable