The BGS Lexicon of Named Rock Units — Result Details

Hibernian Greensands Group

Computer Code: HBG Preferred Map Code: notEntered
Status Code: Full
Age range: Cenomanian Age (KE) — Santonian Age (KS)
Lithological Description: Glauconitic "marls" (calcareous mudstones), argillaceous siltstones and calcareous sandstones, and quartzose sands. Sequence divided into four formations, as noted under Geographical Limit.
Definition of Lower Boundary: The Lower Boundary is unconformable on a variety of older formations at a major regional erosional break at the base of the Belfast Marls Formation.
Definition of Upper Boundary: The upper boundary is unconformable at a major regional erosional break. Overlain by various formations of the Ulster White Limestone Group.
Thickness: About 21m to 22m in the Carrickfergus, Larne, Antrim and Belfast sheet areas.
Geographical Limits: Northern Ireland. As a thin basal Cretaceous unit over structural highs and in the North Antrim Basin, where the group is undivided. Fullest development in the Midland Valley (East Antrim Basin) and the Southern Uplands as defined in Fletcher (1977) where the group is divided into the Belfast Marls Formation, Island Magee Siltstones Formation, Collinwell Sands Formation and the Kilcoan Sands Formation.
Parent Unit: Not Applicable (-)
Previous Name(s): Mulatto (-4086)
Hibernian Greensand Formation (-3458)
Hibernian Greensand (-4084)
Hibernian Greensands (Part) (-4085)
Greensands (*408)
Upper And Lower Hibernian Greensands (-952)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Collin Glen district southwest of Belfast. See Manning, Robbie and Wilson (1970, 64-71). 
Reference Section  Magheramorne borehole Reference Number 84NW/7 [342972 397818] and area around. Notation J above is replaced by an initial 3 for both the easting and northing to give a full National Grid Reference. See Griffith and Wilson (1982, 44-49) 
Reference Section  Cloghfin Port. See Griffith and Wilson (1982, 44-49). 
Reference Section  Kilcoan Old Quarry on Island Magee. See Griffith and Wilson (1982, 44-49). 
Reference(s):
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). 
Hancock, J M. 1961. The Cretaceous System in Northern Ireland. Quarterly Journal of the Geological Society of London, Vol. 117, 11-36. 
Fletcher, T P. 1967. Correlation of the Cretaceous exposures of east Antrim. Unpublished MSc Thesis, Queens University, Belfast. 
Tate, R. 1865. On the correlation of the Cretaceous formations of north-east Ireland. Quarterly Journal of the Geological Society of London, Vol. 21, 15-44. 
Griffith, A E and Wilson, H E. 1982. Geology of the country around Carrickfergus and Bangor. Memoir of the Geological Survey of Northern Ireland. Sheet 29 (Northern Ireland). 
Portlock, J E, 1843. Report on the Geology of the County of Londonderry and parts of Tyrone and Fermanagh. HMSO, Dublin. 
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 
Reid, R E H. 1971. The Cretaceous rocks of north-eastern Ireland. Irish Naturalists' Journal, Vol.17, 105-129. 
Whitehurst, J. 1786. An inquiry into the original state and formation of the Earth; deduced from facts and the laws of nature. 2nd Edition. (London: W Bent.) 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
N28