Computer Code: |
CLHS |
Preferred Map Code: |
ClHS |
Status Code: |
Full |
Age range: |
Arnsbergian Substage (CG)
— Arnsbergian Substage (CG) |
Lithological Description: |
Siltstone, grey, sandy, micaceous, calcareous with rhythmic layers of fine-grained red-brown weathering, sandstone to 1cm; sporadic to common layers of sandy calcisiltite; rare to common Sanguinolites and bellerophontids. NOTE: This is a distinct/unique lithology within the Roeburndale Formation. The formation consists of delta slope siltstones with sandstones. There were previously three known marine bands with goniatite/bivalve faunas. The Close Hill Siltstone is a fourth new marine band. |
Definition of Lower Boundary: |
Gradational to grey planty siltstones with common planty micaceous fine- to medium-grained sandstones over 10cm. (Delta slope deposits). |
Definition of Upper Boundary: |
As lower boundary. |
Thickness: |
c. 60m |
Geographical Limits: |
Not known; probably extensive. Known from large area of Lancaster Fells, and probably extends throughout Lancaster Sheet. |
Parent Unit: |
Roeburndale Member (RBL)
|
Previous Name(s): |
Close Hill Siltstone Member [Obsolete Name and Code: Use CLHS]
(-4551)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Section |
Raghill Beck, near Close Hill. Bed of stream and meander scarps along Raghill Beck. |
Reference Section |
Wray Borehole, 220-280m depth. |
Reference Section |
Hamstone Gill. (top c.16m only well exposed). |
Reference(s): |
Slinger, F C, 1936. Millstone Grit and glacial geology of Caton Moor near Lancaster. Report of the British Association for the Advancement of Science, Blackpool 1936, 345. |
Brandon, A, Aitkenhead, N, Crofts, R G, Ellison, R A, Evans, D J, and Riley, N J. 1998. Geology of the country around Lancaster. Memoir of the British Geological Survey, Sheet 59 (England and Wales). |
Waters, C N, Waters, R A, Barclay, W J, and Davies, J R. 2009. Lithostratigraphical framework for Carboniferous successions of Southern Great Britain (Onshore). British Geological Survey Research Report, RR/09/01. 184pp. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E059
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