| Computer Code: |
CEO |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Arundian Substage (CJ)
— Arundian Substage (CJ) |
| Lithological Description: |
Massive to thick-bedded, locally cross-bedded ooid grainstones. Palaeokarstic surface at the top. Locally overlain by a thin clay palaeosol. Dolomitized along the southeast crop of the South Wales Coalfield. Interpreted to have been deposited in a barrier environment. |
| Definition of Lower Boundary: |
Gradational junction with the underlying skeletal, peloidal and oolitic packstone/grainstones of the underlying High Tor Limestone Formation. Base taken at incoming of a predominantly oolitic grainstone sequence. |
| Definition of Upper Boundary: |
Taken at top of the clay palaeosol capping the Formation, or the top of the underlying palaeokarstic surface if the clay is absent. The palaeosol/palaeokarst is sharply overlain by a bed of grey calcareous mudstone, overlain by thin- to medium-bedded, fine- to coarse-grained crinoidal skeletal packstones of the Argoed Limestone Member of the Cornelly Oolite Formation. |
| Thickness: |
13m in the northern Vale of Glamorgan, thickening southwards to 40m in the central part of the Vale of Glamorgan. |
| Geographical Limits: |
Northern part of the Vale of Glamorgan [ST 00 74]. Passes southwards into upper part of High Tor Limestone Formation. Relationship to coeval Goblin Oolite Formation in the Bristol Mendip [ST 50 65] area, unknown. |
| Parent Unit: |
Cornelly Oolite Formation (CNLL)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Hendy Quarry, 400m north of Miskin church, Vale of Glamorgan. Entire formation (13m), comprising ooid grainstone, seen, but upper part is high in the quarry face and can only be accessed with difficulty. Contacts with the underlying High Tor Limestone Formation and overlying dolomitised Argoed Limestone Member (part of the Cornelly Oolite Formation) are exposed. (see Waters and Lawrence, 1987.) |
| Reference(s): |
| Waters, R A and Lawrence, D J D. 1987. Geology of the South Wales Coalfield - Part III: the country around Cardiff. Memoir of the British Geological Survey, Sheet 263. (England and Wales). |
| Wilson, D, Davies, J R, Fletcher, C J N, and Smith, M. 1990. The Geology of the South Wales Coalfield, part VI the Country around Bridgend. Memoir of the British Geological Survey, 1:50 000 Geological Sheets 261 and 262 (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E263
E262
|
