| Computer Code: |
ROG |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Marsdenian Substage (CZ)
— Marsdenian Substage (CZ) |
| Lithological Description: |
Medium-to coarse-grained or fine-grained, feldspathic, massive, rarely cross-bedded sandstone, with sole marks and load casts, and turbiditic mudstone. The sandstone is interpreted to have been deposited in a delta-top setting. |
| Definition of Lower Boundary: |
The unit is poorly defined. In the field and in stratigraphic logs, the lower boundary is taken at the base of a sandstone-dominated succession overlying a mudstone interval of Millstone Grit Group that in turn overlies sandstones of either the Five Clouds Sandstone or the Corbar Grit, or mudstone of undifferentiated Millstone Grit Group. |
| Definition of Upper Boundary: |
The upper boundary is taken at the base of a mudstone-dominated succession overlying the Roaches Grit, 10 m to 61 m below fissile black mudstone, that includes a Bilinguites superbilinguis Marine Band. |
| Thickness: |
From 60 m to-375 m thick. |
| Geographical Limits: |
Chinley, Derbyshire (SK 045 825) to Upper Hulme, Staffordshire (SK 01 61) to Rainow, Cheshire (SJ 95 76). |
| Parent Unit: |
Marsden Formation (MARSD)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Partial Type Section |
The Roaches escarpment, in Staffordshire, and Roach End to Hen Cloud, which is a natural cliff section exposing a partial section of the unit (no further details available). Aitkenhead et al., 1985. |
| Reference Section |
Quarry at Lightwood reservoir near Buxton, Derbyshire, which exposes 12.1 m of coarse-grained, well-bedded sandstone. Stevenson and Gaunt, 1971. |
| Reference(s): |
| Smith, E G, Rhys, G H and Eden, R A. 1967. Geology of the country around Chesterfield, Matlock, and Mansfield. Memoir of the Geological Survey of Great Britain. England and Wales Sheet 112. |
| Jones, C M, 1980. Deltaic sedimentation in the Roaches Grit and associated sediments (Namurian R2b) in the south-west Pennines. Proceedings of the Yorkshire Geological Society Vol.43, Pt.1, 39-67. |
| Stevenson, I P and Gaunt, G D, 1971. Geology of the country around Chapel-en-le-Frith. Memoir of the Geological Survey of Great Britain, England and Wales, Sheet 99. |
| Aitkenhead, N, Chisholm, J I, and Stevenson, I P. 1985. Geology of the country around Buxton, Leek and Bakewell. Memoir of the British Geological Survey, England and Wales Sheet 111. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E098
E110
E111
E099
|
