| Computer Code: |
CLNE |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Aptian Age (KP)
— Aptian Age (KP) |
| Lithological Description: |
Cross-bedded, well-sorted, sub- to well-rounded quartzose sandstone. The lower part of the formation is fine- to medium-grained; the upper part is medium-grained sandstone and is more argillaceous. Thin mudstone drapes occur on cross-bedded surfaces in both units, and fossil wood, including logs, is common or abundant. The contact between the two units is either gradational or marked by a scoured surface. |
| Definition of Lower Boundary: |
Unconformable, burrowed erosion surface with the underlying mudstones of the Kimmeridge Clay Formation. The surface is marked by a pyritic, phosphatic and quartz pebble bed, containing derived Kimmeridgian fossils and lignite. |
| Definition of Upper Boundary: |
A sharp erosive junction with the overlying coarse-grained, poorly sorted ferruginous sandstone of the Carstone Formation, marked by a concentration of quartz pebbles in the base of the Carstone and large burrows that penetrate the top of the Calne Sands Formation. |
| Thickness: |
5.5 to 7.8m according to Hesselbo et al. (1990), although Owen et al. (1996) recorded up to 12m. |
| Geographical Limits: |
North Wiltshire. |
| Parent Unit: |
Lower Greensand Group (LGS)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Sand pit ("Pearce's Old Pit") [SU 017 713] near Calne, Wiltshire. Where the full succession was previously visible. Current status unknown. |
| Reference(s): |
| Casey, R, 1961. The stratigraphical palaeontology of the Lower Greensand. Palaeontology, Vol.3, 487-621. |
| Owen, H G, Shephard-Thorn, E R and Sumbler, M G. 1996. Lower Cretaceous. 61-75 in Sumbler, M G (Ed), British Regional Geology: London and the Thames Valley (4th edition). (London: HMSO for the British Geological Survey.) |
| Hesselbo, S P, Coe, A L, Batten, D J and Wach, G D. 1990. Stratigraphic relations of the Lower Greensand (Lower Cretaceous) of the Calne area, Wiltshire. Proceedings of the Geologists' Association, Vol.101, 265-278. |
| Knox, R W O'B. 1999. Anomalous cross-bedding directions in the late Aptian Lower Greensand of southern England and their possible correlative significance. Proceedings of the Geologists' Association, Vol.110, 77-80. |
| Ramsey, A C, Aveline, W T and Hull, E. 1858. Geology of parts of Wiltshire and Gloucestershire. Memoir of the Geological Survey. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
