| Computer Code: |
LR |
Preferred Map Code: |
LR |
| Status Code: |
Full |
| Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
| Lithological Description: |
Acid ash-flow tuff, welded and non-welded, volcanic breccias and rhyolite intrusions. |
| Definition of Lower Boundary: |
Overlies sandstones and silty mudstones of Cwm Eigiau Formation. |
| Definition of Upper Boundary: |
Overlain by basic volcanic deposits of Bedded Pyroclastic Formation. |
| Thickness: |
600m |
| Geographical Limits: |
Central Snowdonia. |
| Parent Unit: |
Snowdon Volcanic Group (SV)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Lliwedd, Snowdon. |
| Reference(s): |
| Howells, M F and Smith, M. 1997. Geology of the country around Snowdon. Memoir of the British Geological Survey, Sheet 119 (England and Wales). (London: The Stationery Office). 104pp. |
| Howells, M F, Reedman, A J and Campbell, S D G, 1991. Ordovician (Caradoc) marginal basin volcanism in Snowdonia (north-west Wales). (London: HMSO for the British Geological Survey). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E119
E106
|
