Whitehaven Sandstone Formation
Whitehaven Sandstone Formation (WS), Carboniferous, Northern England Province
Whitehaven Sandstone Formation is part of the Warwickshire Group
Name
The name is derived from the area around Whitehaven in west Cumbria.
Lithology
A red-bed succession. The lower part, the Bransty Cliff Sandstone Member (the Whitehaven Sandstone of Akhurst et al., 1997[1]), comprises red to deep purple or purplish brown, cross-bedded, micaceous, medium- to coarse-grained sandstone. There are interbeds of pink to red or grey mudstone and siltstone and thin palaeosols are present locally. These beds are overlain by a thick heterogenous, dominantly red succession (the Millyeat Member) of mudstone, sandstone and marl with thin coals and limestones with Spirorbis sp.
Genetic interpretation
The lower part of the formation was deposited from a major braided river system that flowed from the north-east. The upper part of the formation represents deposition in interdistributary bay or lacustrine environments with minor river channels (Akhurst et al., 1997[1]). The reddening was either primary or early diagenetic.
Stratotype
Partial type sections in the formation include the Whitehaven Harbour cliff sections around (NX 974 192) where the lower arenaceous part of the formation (the Bransty Cliff Sandstone Member with mainly sandstone and subsidiary mudstone and siltstone interbeds) is well exposed, and the Frizington Hall Borehole (BGS Registration Number NY01NW/174) (NY 0189 1710) from 12.8 m depth to the bottom of the borehole at 174.65 m depth.
Lower and upper boundaries
The base of the formation is taken where the non-reddened, cyclical, mudstone-dominated succession with thin coals of the underlying Pennine Coal Measures Group are succeeded unconformably by red sandstones (Figure 9, Column 13; Figure 14, Column 1). The unconformity cuts down to the Aegiranum Marine Band (AGMB) or, locally older strata (Akhurst et al., 1997).
The upper boundary of the formation is the base of the sub-Permian unconformity, which is overlain by the coarse, poorly bedded, poorly to moderately sorted, generally massive, matrix or clast-supported, typically pebble-grade, breccias of the Permian Brockram (Appleby Group).=== Thickness ===
The formation is at least 280 m thick. The Bransty Cliff Sandstone Member is at least 100 m thick. The Millyeat Member is 180 m thick.
Distribution and regional correlation
Within the Northern England Province the formation is recognised in north and west Cumbria.
Age and biostratigraphical characterisation
Late Bolsovian to early Asturian (Westphalian D) as indicated by plant remains and the presence of the nonmarine bivalve Anthraconauta phillipsii (Eastwood et al., 1931[2]). To the north-east similar strata have an Asturian (Westphalian.D), Tenuis Chronozone fauna (Eastwood et al., 1968[3]).
Formal subdivisions
See also Appendix 1. Members of the Whitehaven Sandstone Formation, in ascending stratigraphical order, include:
Bransty Cliff Sandstone Member
References
- ↑ 1.0 1.1 Akhurst, M C, Chadwick, R A, Holliday, D W, McCormac, M, McMillan, A A, Millward, D, and Young, B.1997.Geology of the west Cumbria district.Memoir of the British Geological Survey, Sheets 28, 37 and 47 (England and Wales).
- ↑ Eastwood, T, Dixon, E E L, Hollingsworth, S, and Smith, B.1931.The geology of the Whitehaven and Workington District.Memoir of the Geological Survey, Sheet 28 (England and Wales).
- ↑ Eastwood, T, Hollingworth, S E, Rose, W C C, and Trotter, F M.1968.Geology of the country around Cockermouth and Caldbeck.Memoir of the Geological Survey of Great Britain, Sheet 23 (England and Wales).