Computer Code: |
BK |
Preferred Map Code: |
notEntered |
Status Code: |
Full |
Age range: |
Cisuralian Epoch (PLC)
— Early Triassic Epoch (TE) |
Lithological Description: |
Matrix and clast-supported breccias; clasts range from small pebble to cobble; the matrix is variously clay, silt and/or sand. The clasts reflect the local source rocks. |
Definition of Lower Boundary: |
Sharp and irregular unconformable contact with older rocks, usually Dinantian, Westphalian or Ordovician (Borrowdale Volcanic Group). Geophysically the base is usually sharp, marked by a decrease in gamma-ray values and sonic interval transit times. This is most marked in West Cumbria where Brockram overlies the Carboniferous Limestone (Dinantian). |
Definition of Upper Boundary: |
May be sharp or transitional in West Cumbria. Sharp contact with overlying dolomite or dolomitic mudstones of the St Bees Evaporite Formation is marked by a rapid decrease in gamma-ray values and a less marked decrease in sonic interval transit times. |
Thickness: |
Very variable, up to 160 m. |
Geographical Limits: |
Vale of Eden, West Cumbria, Furness. |
Parent Unit: |
Appleby Group (APY)
|
Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Area |
Vale of Eden |
Reference(s): |
Smith, B, 1919. Iron Ores: Haematite of West Cumberland, Lancashire and the Lake District.Special Report on Mineral Resources; Memoir of the Geological Survey of Great Britain. |
Goodchild, J G, 1885. The Penrith Sandstone. Transaction of the Cumberland and Westmorland Association for the Advancement of Literature and Science, Vol.9 (for 1883-4), 31-51. |
Goodchild, J G, 1893. Observations on the New Red Series of Cumberland and Westmorland. Transactions of the Cumberland and Westmorland Association for the Advancement of Literature and Science, Vol.17 (for 1891-2), 1-24. |
Smith, B. 1924. On the West Cumberland Brockram and its associated rocks. Geological Magazine, Vol.61, 289-308. |
Taylor, F M, 1988. A Lexicon of New Red Sandstone stratigraphy (written to conform with the International Lexicon of Stratigraphy Vol. 1, Europe Part 3a, England, Wales and Scotland, Section 1X). Mercian Geologist, Vol.11, 1-143. |
Sedgwick, A, 1836. On the New Red Sandstone Series in the basin of the Eden and northwestern coasts of Cumberland and Lancashire. Transaction of the Geological Society of London (Series 2), Volume.4, 383-407. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E018
E037
E011
S006
E028
E048
E012
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