Computer Code: |
SPRK |
Preferred Map Code: |
notEntered |
Status Code: |
Full |
Age range: |
Carnian Age (TC)
— Carnian Age (TC) |
Lithological Description: |
Mudstone, greenish grey, silty, sandy, dolomitic, well indurated; nodules of celestite (strontium sulphate) common, especially towards top. |
Definition of Lower Boundary: |
Conformable, at abrupt or near abrupt upward change from the reddish brown mudstone of the Mercia Mudstone Group (undivided) to the greenish grey dolomitic sandy mudstone of the Stoke Park Rock Bed. |
Definition of Upper Boundary: |
Conformable, at gradational upward transition from greenish grey mudstone with celestite of the Stoke Park Rock Bed to reddish brown and greenish grey mottled mudstone of the Mercia Mudstone Group. |
Thickness: |
0.5 to 2m |
Geographical Limits: |
Crops out in northern part of Bristol area and in south Gloucestershire. |
Parent Unit: |
Mercia Mudstone Group (MMG)
|
Previous Name(s): |
Severnside Evaporite Bed [Obsolete Name and Code: Use SPRK]
(-3043)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Area |
Stoke Park, north of Stapleton, Bristol. Kellaway and Welch (1993). |
Reference(s): |
Kellaway, G A and Welch, F B A. 1993. Geology of the Bristol district. Memoir of the British Geological Survey Special Sheet [England and Wales]. |
Nickless, E F P, Booth, S J and Mosley, P N. 1975. The celestite deposits of the Bristol area. Transactions of the Institution of Mining and Metallurgy, Vol.B84, 62-64. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
none recorded or not applicable |