Duddon Conglomerate Member
Duddon Conglomerate Member (DUCO), Carboniferous, Northern England Province
Duddon Conglomerate Member is part of the Marsett Formation
Name
See Johnson et al. (2001)[1]; Rose and Dunham (1977)[2].
Lithology
Conglomerate, sandstone and mudstone, mainly red-brown with pale green and mottled layers, with traces of evaporite. Large clasts (pebbles up to 15.cm) are well rounded, commonly with ferruginous skins. Clast lithologies all occur locally and include Borrowdale Volcanic Group andesite, tuff and rhyolite, Silurian ‘grit’ and ‘greywacke’ and Eskdale Granite and Ennerdale Granophyre.
Stratotype
The type section is a borehole (BGS Registration Number SD27NW/323) (SD 2113 7991) between 88.52 and 255.50 m depth (see Rose and Dunham, 1977[2]).
Lower and upper boundaries
The base is unconformable on the top of the Lower Palaeozoic basement (Figure 9, Column 14).
The top of the member occurs at upward change from conglomerate beds to grey, red and green marine mudstone and limestone with subordinate thin conglomerate beds of the Martin Limestone Formation. The junction may be sharply gradational or possibly an onlap surface.
Thickness
Maximum recorded 240 m in Dunnerholme (Rose and Dunham, 1977[2]).
Distribution and regional correlation
Furness, Cumbria confined to the area of the Duddon Estuary.
Age
Courceyan.
References
- ↑ Johnson, E W, Soper, N J, and Burgess, I C.2001.Geology of the country around Ulverston.Memoir of the British Geological Survey, Sheet 48 (England and Wales)
- ↑ 2.0 2.1 2.2 Rose, W C C, and Dunham, K C.1977.Geology and hematite deposits of South Cumbria.Economic Memoir of the Geological Survey of Great Britain, Sheet 58, part 48 (England and Wales)