The BGS Lexicon of Named Rock Units — Result Details
Portrush Chalk Formation
Computer Code: | PRC | Preferred Map Code: | notEntered |
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Status Code: | Full | ||
Age range: | Campanian Age (KC) — Campanian Age (KC) | ||
Lithological Description: | Limestone (chalk) with many tabular flint bands and Inoceramus debris in upper part. In the south Antrim area (Southern Uplands High) there are important hardground non-sequences of green-coated chalk pebbles called the South Antrim Hardgrounds (of ?member status). | ||
Definition of Lower Boundary: | The lower boundary is conformable, on the Garron Chalk Formation, at a bedding plane beneath a prominent continuous tabular flint. | ||
Definition of Upper Boundary: | The upper boundary is taken at a prominent bedding plane above Inoceramus-rich chalk with tabular flint, where it is overlain by chalk of the Ballymagarry Chalk Formation | ||
Thickness: | 14.28m in the type section. | ||
Geographical Limits: | Found throughout Northern Ireland but is generally absent from much of the East Antrim (Midland Valley) Basin due to pre-Palaeogene basalt erosion. Oversteps onto older strata over the Londonderry Shelf. | ||
Parent Unit: | Ulster White Limestone Group (UWLF) | ||
Previous Name(s): | Portrush Chalk Member [Obsolete Name and Code: Use PRC]
(-2379)
Green Beds [Obsolete Name and Code: Use PRC] (-2748) Cardiaster Beds [Obsolete Name and Code: Use PRC] (-1770) Portrush Chalk [Obsolete Name and Code: Use PRC] (-1771) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Type Section | Taken at the south-facing wall of the older and deeper Ballymagarry Quarry, immediately above the main cave that passes beneath the Portrush - Bushmills Road. Fletcher (1977). Taken together with the Sliddery Cove cliffs a complete succession can be viewed. | ||
Type Section | Sliddery Cove Cliffs east of Portrush. Fletcher (1977). Taken together with the Ballymagarry quarry a complete succession can be viewed. | ||
Reference Section | Garron Point in East Antrim. | ||
Reference(s): | |||
Fletcher, T P. 1977. Lithostratigraphy of the Chalk (Ulster White Limestone Formation) in Northern Ireland. Report of the Institute of Geological Sciences, No. 77/24. | |||
Fletcher, T P. 1967. Correlation of the Cretaceous exposures of east Antrim. Unpublished MSc Thesis, Queens University, Belfast. | |||
Wilson, H E. 1972. The regional geology of Northern Ireland. (Belfast: HMSO for Geological Survey of Northern Ireland.) 113pp. | |||
Manning, P I, Robbie, J H and Wilson, H E. 1970. Geology of Belfast and the Lagan Valley. Memoir of the Geological Survey of Northern Ireland, Sheet 36 (Northern Ireland). | |||
Hopson, P M. 2005. A stratigraphical framework for the Upper Cretaceous Chalk of England and Scotland, with statements on the Chalk of Northern Ireland and the UK Offshore Sector. British Geological Survey Research Report RR/05/01 102pp. ISBN 0 852725175 | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
none recorded or not applicable |