Category:Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup: Difference between revisions
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Revision as of 12:50, 28 January 2014
Name
Proposed by Fletcher (1977) as the Post- Larry Bane Chalk White Limestone as an informal term to cover the upper Campanian and Maastrichtian Chalks above the highest of three distinctive and traceable erosion surfaces marking the top of the Larry Bane Chalk Formation.
Type section
Ballycastle area [D 115 420], North Antrim Basin.
Primary Reference Section
Cliff and quarry sections around Ballycastle [D 114 420]; Whiterocks [C 893 409] and Garron Point [D 301 239].
Formal subdivisions
Fletcher (1977) proposed eight members that are regarded as formations herein. They are in ascending order the Ballintoy Chalk formation, Glenarm Chalk Formation, Garron Chalk Formation, Portrush Chalk Formation, Ballymagarry Chalk Formation, Tanderagee Chalk Formation, Port Calliagh Chalk Formation and the Ballycastle Chalk Formation
Lithology
Limestone (chalk) with layers of nodular, tabular and ‘paramoudra’ type flints.
Definition of upper boundary
Placed at the erosion surface at the top of Ulster White Limestone Group sequence beneath Palaeogene Antrim Basalts.
Definition of lower boundary
Placed at base of Ballintoy Chalk Formation at the top of the Larry Bane Chalk Formation where it is marked by the upper of three persistently strong erosion surfaces.
Thickness
89.28m from type sites of constituent members, but the full thickness is very variable due to pre-Palaeogene Basalts erosion.
Distribution
Known throughout Northern Ireland. Its major development is in the North Antrim, East Antrim and Southern Upland basins. Oversteps onto structural highs.
Previous names
None formally but may be considered as the partial equivalent to those defined as ‘Beds of the zone of Belemnitella mucronata’ by Hancock (1961). This group of sediments are usually easily recognised by the presence, in sections, of the characteristic underlying Larry Bane Chalk Formation and is reported by Fletcher (1977) to be recognisable within downhole geophysical logs.
Parent
Ulster White Limestone Group.
Age and biostratigraphy
Upper Cretaceous, Upper Campanian to Maastrichtian. Belemnitella mucronata to Belemnella occidentalis zones.
References
Fletcher (1967, 1977); Griffith and Wilson (1982
Pages in category "Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup"
The following 8 pages are in this category, out of 8 total.
- Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup: Ballintoy Chalk Formation
- Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup: Glenarm Chalk Formation
- Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup: Garron Chalk Formation
- Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup: Portrush Chalk Formation
- Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup: Ballymagarry Chalk Formation
- Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup: Tanderagee Chalk Formation
- Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup: Port Calliagh Chalk Formation
- Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup: Ballycastle Chalk Formation