Computer Code: |
TYFV |
Preferred Map Code: |
TF |
Status Code: |
Full |
Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
Lithological Description: |
Basalt lavas and pillow breccias with hyaloclastite, basaltic tuff; mudstone intercalations. |
Definition of Lower Boundary: |
Rests on mudstones associated with the Lower Crafnant Volcanic Formation. |
Definition of Upper Boundary: |
Overlain by part of the Nod Glas (= Cadnant Shales). |
Thickness: |
500m |
Geographical Limits: |
Restricted to the area of Tal y Fan, 5km north west of Dolgarrog. |
Parent Unit: |
Snowdon Volcanic Group (SV)
|
Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Reference Section |
Tal y Fan. |
Reference(s): |
Howells M F, Reedman A J and Leveridge B E. 1985. Geology of the country around Bangor: Explanation for 1:50 000 geological sheet 106 (England and Wales). British Geological Survey Sheet Explanation. [London: HMSO.] 34pp. |
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: |
E106
E094
|