| Computer Code: |
LPLB |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Frasnian Age (DR)
— Famennian Age (DA) |
| Lithological Description: |
The Lower Plateau Beds unconformably overlie the Brownstones Formation and comprises brick red sandstones, locally gritty and conglomeratic, and interbeds of red-brown mudstone. |
| Definition of Lower Boundary: |
At unconformity where a basal 1.2 to 1.5 m-thick red mudstone bed rich in quartz granules overlies the more drab red-brown sandstones of the Brownstones Formation. |
| Definition of Upper Boundary: |
At the base of the Afon y-Waen fish bed. |
| Thickness: |
15 - 24 m. |
| Geographical Limits: |
South Powys, on the north-east crop of the South Wales coalfield from the River Neath to Afon Crawnon. |
| Parent Unit: |
Plateau Beds Formation [Obsolete: use PNYF] (PLB)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Brecon Beacons area, Powys [SO 00 15]. Hall et al., 1973. |
| Reference Section |
Well exposed section in the Afon Llia [SN 9340 1472]. Taylor and Thomas, 1974. |
| Reference(s): |
| Hall, I H S, Taylor, K, and Thomas, L P. 1973. The stratigraphy of the Upper Old Red Sandstone in south Breconshire. Bulletin of the Geological Survey of Great Britain, No. 44, 45-62. |
| Taylor, K, and Thomas, L P. 1974. Field meeting in the Upper Old Red Sandstone of south Breconshire. Proceedings of the Geologists' Association, Vol. 85, 423-432. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E231
|
