The BGS Lexicon of Named Rock Units — Result Details
Green Ammonite Member
Computer Code: | GAB | Preferred Map Code: | GA |
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Status Code: | Full | ||
Age range: | Pliensbachian Age (JE) — Pliensbachian Age (JE) | ||
Lithological Description: | Medium grey mudstones, with irregular limestones developed at three principal horizons (Lower Limestone; Red Band; and Upper Limestone). Phelps, 1985, beds 7 to 41. | ||
Definition of Lower Boundary: | Top of Belemnite Stone (bed 121 of Lang, W D, et al, 1923). Conformable junction with Belemnite Marl Member. | ||
Definition of Upper Boundary: | Base of lowest bed of the Three Tiers Sandstone (=base of Eype Clay Member of Dyrham Formation). | ||
Thickness: | To 31m | ||
Geographical Limits: | Southwest Dorset, United Kingdom. Mapped on Sheet 327 (Bridport). Northern limit not yet proved. | ||
Parent Unit: | Charmouth Mudstone Formation (CHAM) | ||
Previous Name(s): | Wear Cliff Beds [Obsolete Name and Code: Use GAB]
(-270)
Green Ammonite Beds [Obsolete Name and Code: Use GAB] (-1550) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Type Section | Cliffs around Golden Cap, near Seatown, Dorset. Lang, W D, 1936. | ||
Reference(s): | |||
Arkell, W J. 1933. The Jurassic System in Great Britain [Oxford: Clarendon Press.] | |||
Lang, W D, 1936. The Green Ammonite Beds of the Dorset Lias. Quarterly Journal of the Geological Society, London, Vol.92, 423-455. | |||
Day, E C H, 1863. On the Middle and Upper Lias of the Dorsetshire Coast. Quarterly Journal of the Geological Society of London, Vol.19, 278-297. | |||
Lang, W D, 1914. The geology of Charmouth cliffs, beach and fore-shore. Proceedings of the Geologists' Association, Vol.25, 293-360. | |||
Woodward, H B and Ussher, W A E, 1911. Sidmouth and Lyme Regis. Memoir of the Geological Survey, Sheets 326 and 340 (England and Wales). | |||
Phelps, M C, 1985. A refined ammonite biostratigraphy for the middle and upper Carixian (ibex and davoei zones, Lower Jurassic) in north-west Europe and stratigraphical details of the Carixian-Domerian boundary. Geobios, Vol.18, 321-361. | |||
Lang, W D, 1913. The lower Pleinsbachian - 'Carixian' - of Charmouth. Geological Magazine, Vol.10, 401-412. | |||
Hesselbo, S P and Jenkyns, H C A, 1995. A comparison of the Hettangian to Bajocian successions of Dorset and Yorkshire. 105-150 in Taylor, P D (Editor). Field geology of the British Jurassic (London Geological Society). | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
E327 E341 E342 E343 |