The BGS Lexicon of Named Rock Units — Result Details
Burnham Chalk Formation
| Computer Code: | BCK | Preferred Map Code: | BCk |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Turonian Age (KT) — Santonian Age (KS) | ||
| Lithological Description: | White, thinly-bedded chalk with common tabular and discontinuous flint bands; sporadic marl seams. Formal subdivision: none as defined here, but there are many named marl and flint bands throughout the succession that are used to divide the formation. They are all of bed status. | ||
| Definition of Lower Boundary: | The lower boundary is at a marked change from massive, rubbly-weathering chalks below, to harder, thinly bedded or nodular chalk above. This horizon lies just below the Ravendale Flint, a tabular or semi-tabular flint up to 0.25m thick, which is the lowest such flint in the Chalk Group and base of the chalk unit in which such flint bands are common. The lowest few metres of the formation comprises hard chalks and thick, closely spaced, tabular flints, which produce a topographic feature by which the base of the formation can be mapped, and a characteristic geophysical log signature enabling its identification in boreholes. | ||
| Definition of Upper Boundary: | The upper boundary is the top of the highest flint band in the thick, flint-rich unit of chalk (Burnham Formation), succeeded by flint-free chalks (Flamborough Formation). At Flamborough Head, this is the High Stacks Flint, but elsewhere may be at a different horizon. The change is particularly well marked on borehole sonic velocity logs. | ||
| Thickness: | The formation is about 130m thick; equivalent beds in north Norfolk are approximately 100m thick (based on Wood et al., 1994), suggesting thinning of the Burnham Chalk Formation in the south of the region. North of the Humber, the Burnham Chalk Formation is 140m thick (Whitham, 1991) but it thins to 85 to 100m over the Market Weighton High. A complete section of the formation is exposed in the cliffs north of Flamborough Head, from Selwicks Bay to North Landing, where Rowe (1904) recorded a thickness of 105m. However, bed-by-bed measurements of the lower part of the formation indicate that it is thicker, perhaps 160m for the whole formation. The difference in these figures suggests that the top of the formation in the Cleveland Basin (as defined by the presence of flints) lies at a lower horizon than in the south, perhaps just above the Middleton Marl (based on preliminary correlation of geophysical logs). | ||
| Geographical Limits: | Yorkshire and Lincolnshire Wolds and the superficial deposit-covered area to the east, from Flamborough Head south to the Mablethorpe-Chapel St Leonards area on the Lincolnshire coast (see Sumbler, M G, 1999, Fig.1). Known throughout the Northern Province. | ||
| Parent Unit: | White Chalk Subgroup (WHCK) | ||
| Previous Name(s): | Chalk with Flints (Upper Part) [Obsolete Name and Code: Use BCK]
(-1333)
Burnham Formation [Obsolete Name and Code: Use BCK] (-2585) Upper Chalk (lower part) [Obsolete Name and Code: Use BCK] (-3824) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Humberside area of North Lincolnshire. | ||
| Partial Type Section | The exposure of the contact with the Welton Chalk and the lower part of the formation (Basal boundary) is at the disused Burnham Lodge Quarry near Barrow upon Humber, Lincolnshire. Gaunt, G D, et al., 1992. | ||
| Reference Section | Coastal cliffs between North Landing and Flamborough Head. Because of structural complications and inaccessibility, this section, that would constitute the type section for the formation, has never been described in detail, but see e.g. Rowe, A W, 1904; Neale, J W, 1974; Rawson, P F and Whitham, F, 1992, a, b. | ||
| Reference(s): | |||
| Neale, J W. 1974. Cretaceous. 225-245 in Rayner, D H and Hemingway, J E (editors), The geology and mineral resources of Yorkshire. (Leeds: Yorkshire Geological Society.) | |||
| Rowe, A W. 1904. The zones of the White Chalk of the English coast. IV - Yorkshire. Proceedings of the Geologists' Association, Vol.18, 193-296. | |||
| Sumbler, M G. 1999. The stratigraphy of the Chalk Group in Yorkshire and Lincolnshire. British Geological Survey Technical Report WA/99/02. | |||
| Waters, C N, Smith, K, Hopson, P M, Wilson, D, Bridge, D M, Carney, J N, Cooper, A H, Crofts, R G, Ellison, R A, Mathers, S J, Moorlock, B S P, Scrivener, R C, McMillan, A A, Ambrose, K, Barclay, W J, and Barron, A J M. 2007. Stratigraphical Chart of the United Kingdom: Southern Britain. British Geological Survey, 1 poster. | |||
| Gaunt, G D, Fletcher, T P and Wood, C J. 1992. Geology of the country around Kingston upon Hull and Brigg. Memoir of the British Geological Survey, sheets 80 and 89 (England and Wales). 172pp. | |||
| Rawson, P F and Whitham, F. 1992b. Itinerary XII. Flamborough Head. 100-103 in Rawson, P F and Wright, J K (editors), The Yorkshire Coast. Geologists' Association Guide, No.34. | |||
| Whitham, F. 1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. Proceedings of the Yorkshire Geological Society, Vol.48, 227-254. | |||
| Wood, C J and Smith, E G. 1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. Proceedings of the Yorkshire Geological Society, Vol. 42, 263-287. | |||
| Rawson, P F and Whitham, F. 1992. Itinerary XI. Thornwick Bay and North Landing. 94-99 in Rawson, P F and Wright, J K (editors), The Yorkshire Coast. Geologists' Association Guide, No.34. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E103 E054 E055 E064 E065 E072 E073 E080 E081 E089 E090 E091 | |||