The BGS Lexicon of Named Rock Units — Result Details

Crockanaver Limestone Member

Computer Code: CRVL Preferred Map Code: CRVM
Status Code: Full
Age range: Arundian Substage (CJ) — Arundian Substage (CJ)
Lithological Description: Limestone, medium grey-fawn biosparites, oolitic, crinoidal, thick beds, stylolitic, shale-free, quartz-clastic.
Definition of Lower Boundary: Abrupt contact on dark blue-grey, crinoidal, argillaceous packstones of normal Ballyshannon Limestone Formation.
Definition of Upper Boundary: Variable, either with shales/nodular limestone bed that marks base of succeeding Ederny Limestone Member or, rarely, with argillaceous packstones typical of normal Ballyshannon Limestone Formation.
Thickness: 0 - 15m
Geographical Limits: Kesh-Omagh area of the northwest Carboniferous basin of Ireland.
Parent Unit: Ballyshannon Limestone Formation (BAL)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Section  Disused quarry 1.65 km north east of centre of Parkhill Lough. c.15 metres of grainstones exposed in west wall of quarry. 
Type Area  Carn Ridge, located south and south east of Ederny, County Fermanagh. All quarries expose the contact of the Ederny and Crockanaver Limestone Members and much of the latter unit. 
Mitchell, W I, Johnston, T P and Legg, I C. 2004. Geology of the country around Kesh, Co. Fermanagh and Omagh, Co. Tyrone. Geological Sheets 32 and part of 31 (Kesh) and 33 (Omagh). Geological Survey of Northern Ireland. Technical Report GSNI 04/1. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: