Computer Code: |
CIF |
Preferred Map Code: |
notEntered |
Status Code: |
Pending Upgrade |
Age range: |
Llandovery Epoch (SL)
— Llandovery Epoch (SL) |
Lithological Description: |
Comprises banded mudstones and siltstones. Very minor sandstones. Banding is characteristically wide - 10-30cm +, is common. May reach 60cm. Turbiditic mudstones overlain by oxic or anoxic hemipelagite intervals. Graptolitic units may be present. |
Definition of Lower Boundary: |
Taken to be at the base of a laterally traceable anoxic mudstone (graptolitic) horizon (7878 0050). |
Definition of Upper Boundary: |
Not seen on Sheet 149. |
Thickness: |
At least about 800m thick, top of formation not yet located. |
Geographical Limits: |
Confined to southeast corner of Sheet 149, only present on Sheet SH70SE. Best exposed in base of River Crew. |
Parent Unit: |
Not Entered (?)
|
Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
none recorded or not applicable |
Reference(s): |
Scott, M M. 1990. Geological notes and local details for 1:10,000 Sheet SH70SE Llanwrin, part of 1:50,000 Sheet 149 Cadair Idris. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E149
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