The BGS Lexicon of Named Rock Units — Result Details
Hopeman Sandstone Formation
| Computer Code: | HMSF | Preferred Map Code: | HMSF |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Lopingian Epoch (PUL) — Early Triassic Epoch (TE) | ||
| Lithological Description: | Onshore, predominantly yellowish aeolian sandstones, some deposited by sheet floods; fine- to coarse-grained, with well rounded grains. Basal beds are pebbly. Large-scale, crossbedded or laminated; rarely contorted. Some beds friable, others hard and siliceous. Contains fossil reptiles. Offshore, the Hopeman Sandstone Formation is largely composed of clean sandstones, and is characterized by low gamma-ray values, commonly between 20 and 35 API units. The sandstones are white, pale grey or red, and moderately to well sorted. Grain size is mainly fine or medium, but intervals of coarse, pebbly sandstone have been encountered in southernmost wells. The sandstones have silica, carbonate or anhydrite cements, and are only locally argillaceous. Reddish brown and greenish grey mudstones are interbedded with the sandstones in well 12/26-1; elsewhere they occur only as sporadic partings. Some wells have recorded a few thin beds of pale brown limestone that may be of calcrete type. | ||
| Definition of Lower Boundary: | Onshore, the unconformity with the Devonian Upper Old Red Sandstone. Offshore, the Hopeman Sandstone Formation rests on carbonate, anhydrite, or clastics-dominated Upper Permian sections in different areas of the western Inner Moray Firth. Where the Upper Permian is composed of clastic sediments (Bosies Bank Formation), the boundary is defined by a sharp downward change from sandstone to interbedded mudstone and sandstone (e.g. 11/30-6), marked by a sharp downward increase in gamma-ray values, resistivity and velocity. The facies transition is equally sharp above the carbonate and anhydrite sections. | ||
| Definition of Upper Boundary: | The Hopeman Sandstone Formation is conformably overlain by the Lossiehead Formation throughout the western Inner Moray Firth and by the Burghead Sandstone Formation in coastal outcrops. No marked lithological contrast takes place across the boundary in either setting, but, in offshore sections, the top of the formation is marked by a sharp downward decrease in gamma-ray values. | ||
| Thickness: | The formation is locally more than 70 m thick onshore (Clemmensen, 1987) (E.g. 61 m, Clarkly Hill No. 1 Borehole [NJ 1270 6833]). Offshore, the formation extends over an area of about 4000 km2 of the Inner Moray Firth; it is generally more than 75 m thick and has its maximum recorded thickness of 165 m in block 12/27. | ||
| Geographical Limits: | The Hopeman Sandstone Formation crops out on the southern shores of the Moray Firth near Hopeman, and for a short distance inland (Peacock et al., 1968). | ||
| Parent Unit: | Heron Group (HERO) | ||
| Previous Name(s): | Sandstones of Cutties Hillock (Quarry Wood) [Obsolete Name and Code: Use HMSF]
(-4710)
Sandstones of Hopeman [Obsolete Name and Code: Use HMSF] (-1597) |
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| Alternative Name(s): | Hopeman-Cummingstown Sandstone Cutties Hillock Sandstone |
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| Stratotypes: | |||
| Type Area | Coastal section from Covesea Skerries Lighthouse to Cummingstown, Moray (Peacock et al., 1968). | ||
| Reference Section | Borehole record from Clarkly Hill (No. 1) Borehole (Geological Survey). Depth from surface 347 - 438 ft (Peacock et al., 1968). | ||
| Reference Section | North Sea well 11/30- 6: 1813-1891 m (5948-6205 ft) (Cameron, 1993). | ||
| Reference Section | North Sea well 12/28- 1: 2672.5-2753 m (8768-9032 ft) (Cameron, 1993). | ||
| Reference(s): | |||
| Frostick, L, Reid, I, Jarvis, J and Eardley, H. 1988. Triassic sediments of the Inner Moray Firth, Scotland: early rift deposits. Journal of the Geological Society (London), Vol. 145, 235-248. | |||
| Cameron, T D J. 1993. 4. Triassic, Permian and pre-Permian of the Central and Northern North Sea. In: Knox, R W O'B and Cordey, W G (eds.) Lithostratigraphic nomenclature of the UK North Sea. British Geological Survey, Nottingham. | |||
| Warrington, G, Audley-Charles, M G, Elliott, R E, Evans, W B, Ivimey-Cook, H C, Kent, P E, Robinson, P L, Shotton, F W and Taylor, F M. 1980. A correlation of the Triassic rocks in the British Isles. Special Report of the Geological Society of London, No.13. | |||
| Stephenson, D and Gould, D. 1995. British Regional Geology: the Grampian Highlands (4th edition). (London: HMSO for the British Geological Survey), 67-68. | |||
| Peacock, J D, Berridge, N G, Harris, A L, May, F. 1968. The geology of the Elgin District. Memoir of the Geological Survey of Scotland. Sheets 86 and 96 (Scotland). (Edinburgh: HMSO). | |||
| Clemmensen, L B. 1987. Complex star dunes and associated aeolian bedforms, Hopeman Sandstone Formation (Permo-Triassic), Moray Firth Basin, Scotland. In: Frostick, L E and Reid, I (eds.) Desert sediments: ancient and modern. Geological Society, London, Special Publication No.35, 213-231. | |||
| Benton, M J, and Walker, A D. 1985. Palaeoecology, taphonomy, and dating of Permo-Triassic reptiles from Elgin, north-east Scotland. Palaeontology 28, 207-234. | |||
| Waters, C N, Gillespie, M R, Smith, K, Auton, C A, Floyd, J D, Leslie, A G, Millward, D, Mitchell, W I, McMillan, A A, Stone, P, Barron, A J M, Dean, M T, Hopson, P M, Krabbendam, M, Browne, M A E, Stephenson, D, Akhurst, M C, and Barnes, R P. 2007. Stratigraphical Chart of the United Kingdom: Northern Britain. (British Geological Survey.) | |||
| Westoll, T S. 1951. The vertebrate-bearing strata of Scotland. 18th International Geological Congress, London, 1948, Vol. 9, p. 5-21. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| S095 | |||