| Computer Code: |
WRT |
Preferred Map Code: |
WrT |
| Status Code: |
Full |
| Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
| Lithological Description: |
Andesitic lapilli-tuff, massive. |
| Definition of Lower Boundary: |
Taken at the base of the pyroclastic flow deposit, usually overlying volcaniclastic sandstone in the Waberthwaite Formation succession; basaltic sills may intervene. |
| Definition of Upper Boundary: |
Top of pyroclastic flow deposit, usually overlain by volcaniclastic sandstone, which separates it from the overlying pyroclastic flow deposit (Barrow Tuff Member). |
| Thickness: |
c.140-230m |
| Geographical Limits: |
Between Windy Slack (SD 172 888) and Boadhole (SD 190 878), west of Duddon Bridge near Broughton in Furness, Cumbria. |
| Parent Unit: |
Waberthwaite Tuff Formation (WB)
|
| Previous Name(s): |
Wrayslack Tuffs and Lavas [Obsolete Name and Code: Use WRT]
(-1286)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
On Wrayslack, c.1km west of Duddon Bridge, Cumbria. |
| Reference(s): |
| Mathieson, N A, 1986 Geology, structure and geochemistry of the Ordovician volcanic succession in south west Cumbria. Unpublished Ph.D. thesis, University of Sheffield. |
| Johnson, E W, Soper, N J, Burgess, I C, Ball, D F, Beddoe-Stephens, B, Carruthers, R M, Fortey, N J, Hirons, S, Merritt, J W, Millward, D, Roberts, B, Walker, A B and Young, B. 2001. Geology of the country around Ulverston. Memoir of the British Geological Survey, England and Wales, Sheet 48. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E048
|
