| Computer Code: |
THHB |
Preferred Map Code: |
ThHB |
| Status Code: |
Full |
| Age range: |
Early Triassic Epoch (TE)
— Anisian Age (TA) |
| Lithological Description: |
Sandstone and pebbly sandstone, greyish-brown. Fine- to medium-grained, moderately- to poorly-sorted. Laterally impersistent. Very well cemented in comparison to sandstone units immediately above (Thurstaston Sandstone Member) and below (Wilmslow Sandstone Formation). |
| Definition of Lower Boundary: |
Taken at the base of a maximum 3m thick pebbly sandstone bed (the Thurstaston Hard Sandstone Bed), overlying pebble-free reddish-orange sandstone (Wilmslow Sandstone Formation). |
| Definition of Upper Boundary: |
Taken at the top of a maximum 3m thick pebbly sandstone bed (the Thurstaston Hard Sandstone Bed), underlying pebble-free reddish-orange sandstone (Thurstaston Sandstone Member). |
| Thickness: |
0 to 3m |
| Geographical Limits: |
Wirral Peninsula, west of the Woodchurch Fault (Cheshire Basin). |
| Parent Unit: |
Thurstaston Sandstone Member (THUN)
|
| Previous Name(s): |
Thin inconsistent bed of hard sandstone [Obsolete Name and Code: Use THHB]
(-3081)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
A540, Thurstaston road cutting. 300-600m north of junction with Station Road and Thurstaston Road. Thompson, D B, 1970a. |
| Partial Type Section |
Thurstaston Common, Thurstaston, Wirral. Hough, E, 1999; Lawley, R S, In press |
| Reference(s): |
| Thompson, D B, 1970B. Sedimentation of the Triassic (Scythian) Red Pebbly Sandstones in the Cheshire Basin and its margins. Geological Journal 7, Pt.1, 183-216. |
| Wedd, C B, Smith, B, Simmons, W C and Wray, D A, 1923. The Geology of Liverpool, with Wirral and part of the Flinthsire Coalfield. Memoir of the Geological Survey of Great Britain, Sheet 96 (England and Wales). |
| Hough, E, 1999. The geology of the north Wirral district. British Geological Survey Technical Report WA/98/66. |
| Earp, J R and Taylor, B J, 1986. Geology of the country around Chester and Winsford. Memoir of the British Geological Survey, Sheet 109 (England and Wales). |
| Lawley, R S, in preparation. The geology of the country around Heswall. British Geological Survey Technical Report. |
| Thompson, D B, 1970. The stratigraphy of the so-called Keuper Sandstone Formation (Scythian-?Anisian) in the Permo-Triassic Cheshire Basin. Quarterly Journal of the Geological Society of London, Vol.126, p.151-181. |
| Rice, R C, 1939. The Trias of north-west Wirral. Proceedings of the Liverpool Geological Society 17, 349-370. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E096
|
