| Computer Code: |
YATU |
Preferred Map Code: |
YAT |
| Status Code: |
Full |
| Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
| Lithological Description: |
Welded acidic ash-flow tuffs with pyroclastic breccias. |
| Definition of Lower Boundary: |
Lies on sedimentary rocks of the Cwm Eigiau Formation. |
| Definition of Upper Boundary: |
Underlies part of the Cwm Eigiau Formation. |
| Thickness: |
About 200m |
| Geographical Limits: |
Limited to an area around Yr Arddu, 6km east of Moel Hebog. |
| 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 |
Yr Arddu. |
| Reference(s): |
| Howells, M F, Campbell, S D G, Reedman, A J and Tunnicliff, S P, 1987. A fissure-controlled acidic volcanic centre (Ordovician) at Yr Arddu, North Wales. Geological Journal, Vol.22, 133-149 |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E119
|
