The BGS Lexicon of Named Rock Units — Result Details

Tandinas Limestone Formation [Obsolete Name And Code: Use LEEL]

Computer Code: TDL Preferred Map Code: TDL
Status Code: Index Level
Age range: Asbian Substage (CR) — Asbian Substage (CR)
Lithological Description: Comprises interbedded skeletal limestones and distinctive porcellanous limestones; rests unconformably on cleaved Ordovician mudstones. The formation is capped by the widely recognised Bryn Tirion Member and overlain by the massive or rubbly skeletal limestones of the Penmon Limestone.
Definition of Lower Boundary: Contact with Ordovician rocks.
Definition of Upper Boundary: Top of uppermost porcellanous limestone of the Bryn Tirion Member.
Thickness: 45m
Geographical Limits: Not defined.
Parent Unit: Not Entered (?)
Previous Name(s): Careg-Onen Limestone Formation [Obsolete Name And Code: Use LEEL] (COLF)
Alternative Name(s): none recorded or not applicable
Type Area  Tandinas Quarry, Sheet 94. 
Power, G M. Not published. The Stratigraphy and Sedimentology of the Lower Carboniferous in Anglesey, with special reference to rocks of Asbian(DI) age. Ph.D. Thesis, Queen's University, Belfast, 1977. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: