The BGS Lexicon of Named Rock Units — Result Details

Collinwell Sands Formation

Computer Code: CLLW Preferred Map Code: notEntered
Status Code: Full
Age range: Cenomanian Age (KE) — Turonian Age (KT)
Lithological Description: Pale green to grey coarse-grained unconsolidated sands with some glauconite. Becomes whitish and poorly glauconitic in the Carrickfergus district.
Definition of Lower Boundary: The lower boundary is disconformable at an erosional surface upon the Island Magee Siltstones Formation. This is placed at the change from grey siltstones and marls of the Island Magee Siltstones up into the pale green or grey glauconitic coarse-grained sands of this formation.
Definition of Upper Boundary: The upper boundary is unconformable at an erosion surface with the younger Kilcoan Sands Formation, the so-called Turonian non-sequence within the Hibernian Greensands Group; and also beneath the erosion surface at the base of the Ulster White Limestone Group at basin margins.
Thickness: Maximum of 2.4m at Rungill Burn in the Carrickfergus district.
Geographical Limits: The formation is fully developed in the area southwest of Belfast within the East Antrim Basin and Southern Uplands area. Elsewhere in Northern Ireland the formation may be represented in the condensed successions of the undivided Hibernian Greensands Group.
Parent Unit: Hibernian Greensands Group (HBG)
Previous Name(s): Basement Sands Of The Upper Glauconite Beds (-134)
Chlorite Sands And Sandstones (-135)
Collinwell Sands Member (-1442)
Lower Hibernian Greensands (-3940)
Quartzose Sands (-3941)
Glauconitic Sands (-65)
Alternative Name(s): none recorded or not applicable
Type Area  The formation is best developed southwest of Belfast and was described from a type area around Collin Glen [J 269 702] in terms of the old Glauconitic Sands. This site is reported in Manning, Robbie and Wilson (1970) to be obscured by landslips. The unit was named after the quarry at Collinwell [J 269 701] nearby. 
Reference Section  Kilcoan Old Quarry [J 461 985]. See Fletcher (1967, p.37, Figure 7a) Also numerous localities on the Larne, Antrim, Carrickfergus and Belfast sheet areas (see Griffith and Wilson (1982), Page 48, Figure 16A). 
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). 
Hancock, J M. 1961. The Cretaceous System in Northern Ireland. Quarterly Journal of the Geological Society of London, Vol. 117, 11-36. 
Hume, W F. 1897. The Cretaceous strata of County Antrim. Quarterly Journal of the Geological Society of London, Vol.53, 540-606. 
Reid, R E H. 1971. The Cretaceous rocks of north-eastern Ireland. Irish Naturalists' Journal, Vol.17, 105-129. 
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). 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable