Computer Code: |
GRCG |
Preferred Map Code: |
GrCg |
Status Code: |
Full |
Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
Lithological Description: |
A massive, poorly sorted volcaniclastic breccia, comprising heterolithic volcanic clasts, including abundant pink-weathered rhyolite clasts. |
Definition of Lower Boundary: |
The abrupt change from bedded volcaniclastic sandstone within the Mardale Sandstone Formation to volcaniclastic breccia. |
Definition of Upper Boundary: |
Taken at the sharp base of the overlying thin unit of bedded volcaniclastic sandstone, which is succeeded by massive, weakly eutaxitic, dacitic lapilli-tuff. |
Thickness: |
To 180m |
Geographical Limits: |
Swindale, Cumbria, between Dry Grove Gill [NY 510 122] and Mullender [NY 522 132]. |
Parent Unit: |
Mardale Sandstone Formation (MRL)
|
Previous Name(s): |
Gouther Crag Member
(-940)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Area |
Gouther Crag, 500m south of Truss Gap, Swindale, Cumbria. |
Reference(s): |
Millward, D. 2002. Geology of the area between Haweswater and Shap. British Geological Survey Research Report RR/02/02. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E030
E039
|