The BGS Lexicon of Named Rock Units — Result Details

Abbotsbury Ironstone Formation

Computer Code: ABI Preferred Map Code: AbI
Status Code: Full
Age range: Kimmeridgian Age (JD) — Kimmeridgian Age (JD)
Lithological Description: Iron-ooidal grainstone and sandy packstone, muddy sandstone, clean sandstone and mudstone. Bioturbated and bioclastic in parts.
Definition of Lower Boundary: A disconformable boundary with the underlying Sandsfoot Grit Member (Sandsfoot Formation), marked, in the stratotype area, by the upward lithological change from sandstone with erosion surfaces to iron-ooid packstone.
Definition of Upper Boundary: A conformable junction of the formation with the overlying Kimmeridge Clay Formation, marked by the upward lithological change from sandstone and muddy sandstone to mudstone.
Thickness: 35 to 40m present around Abbotsbury village. Up to 8.4m visible in exposure near Abbotsbury [SY 576 856](Wright and Cox, 2001, p. 61). Up to 57m present in the BGS Abbotsbury boreholes.
Geographical Limits: Geographically restricted to the area of the stratotype locality around Abbotsbury village, and nearby Litton Cheney [SY 552 908] and Rodden [SY 612 842].
Parent Unit: Corallian Group (CR)
Alternative Name(s): none recorded or not applicable
Reference Section  Blind Lane, Abbotsbury. Basal 7.8 to 8.4m seen on Sandsfoot Grit Member. 
Reference Section  BGS Abbotsbury Borehole No.1. (SY58NE 3). 34.2 to 80.2m (TD) depth. 
Reference Section  BGS Abbotsbury Borehole No.2. (SY58NE 4). GL to about 31m depth. 
Type Area  Abbotsbury village. 
Arkell, W J. 1947. Geology of the country around Weymouth, Swanage, Corfe and Lulworth. Memoir of the British Geological Survey. Sheets 341, 342, 343 and small portions of sheets 327, 328 and 329 (England and Wales). 
Blake, J F, and Hudleston, W H. 1877. On the Corallian rocks of England. Quarterly Journal of the Geological Society of London, Vol. 33, 260-405. 
Brookfield, M E. 1973. The palaeoenvironment of the Abbotsbury Ironstone (Upper Jurassic) of Dorset. Palaeontology, Vol. 16, 261-274. 
Brookfield, M E. 1978. The lithostratigraphy of the Upper Oxfordian and Lower Kimmeridgian beds of south Dorset. Proceedings of the Geologists' Association, Vol. 89, 1-32. 
Newell, A J. 2000. Fault activity and sedimentation in a marine rift basin (Upper Jurassic, Wessex basin, UK). Journal of the Geological Society, London, Vol. 157, 83-92. 
Wilson, V, Welch, F B A, Robbie, J A, and Green, G W. 1958. Geology of the country around Bridport and Yeovil. Memoir of the Geological Survey of Great Britain, Sheets 327 and 312 (England and Wales). 
Wright, J K. 1986. A new look at the stratigraphy, sedimentology and ammonite fauna of the Corallian Group (Oxfordian) of south Dorset. Proceedings of the Geologists' Association, Vol. 97, 1-21. 
Wright, J K, and Cox, B M. 2001. British Upper Jurassic Stratigraphy (Oxfordian to Kimmeridgian). Geological Conservation Review Series. No. 21. (Peterborough: Joint Nature Conservation Committee/Chapman and Hall.) 
Cope, J C W. 1971. Dorset natural history reports: geology. Proceedings of the Dorset Natural History and Archaeological Society, Vol. 92, 41-44. 
Jenkyns, H C, and Senior, J R. 1991. Geological evidence for intra-Jurassic faulting in the Wessex Basin and its margins. Journal of the Geological Society, London, Vol. 148, 245-260. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E327 E341 E342