The BGS Lexicon of Named Rock Units — Result Details

Mey Sandstone Member

Computer Code: MEYS Preferred Map Code: notEntered
Status Code: Full, pending ratification
Age range: Paleocene Epoch (GP) — Paleocene Epoch (GP)
Lithological Description: The non-tuffaceous sandstones of the Mey Sandstone Member mostly range from fine to medium, occasionally coarse, sand grade, and commonly include angular clasts of mudstone or limestone. They consist of a succession of superimposed sandstone units, often with sharp, erosional bases; primary sedimentary structures are scarce, with most sandstones being structureless or displaying dewatering structures. The sandstones include sporadic zones of calcite cementation, with more pervasive cementation in the Andrew Sandstone (see below) reflected in consistently higher sonic velocities. Conglomeratic sandstones are present at some levels, especially in the Central Graben, with the coarse fraction being composed of fragments of reworked Paleocene mudstones and Paleocene or Cretaceous chalky limestone. Although the fragments are generally angular, rounded and glauconite-stained pebbles of chalk and flint are encountered in some beds. The sandstones are interbedded with typical variegated, bioturbated Lista mudstones, which become increasingly silty to the west. The tuffite consists of well-sorted, silt to sand grade basaltic tuff particles, generally medium to dark grey-green or brown in colour (Jacque & Thouvenin 1975). On wireline logs it is distinguished from associated sandstones by its high resistivity and by SP values close to those of the associated mudstones. The purest tuffites display exceptionally low gamma values. The tuffaceous sandstones consist of a variable mixture of detrital and tuffaceous grains; they typically display SP and resistivity responses intermediate between those of the non-tuffaceous sandstone and the tuffite. In the extreme west of the area (Quadrant 13), lignite is recorded in association with the Mey Sandstone Member. In the same area, both in-situ lignite and tuffite were encountered in a shallow borehole (Jolley & Morton 1992).
Definition of Lower Boundary: The base of the Mey Sandstone Member is normally marked by a sharp downward change from sandstone to green-grey mudstone, associated with an increase in gamme values and a decrease in velocity. The basal sandstone commonly displays a moderate degree of cementation, apparently through the incorporation of reworked chalk. The underlying Lista mudstone is usually thin, and locally it is absent, so that the sandstone rests directly on grey mudstones of the Maureen Formation.
Definition of Upper Boundary: The top of the Mey Sandstone Member is typically defined by a downward change from green-grey to grey-green mudstone to sandstone, associated with a decrease in gamma values and an increase in velocity. Locally, however, the member is overlain directly by sandstone of the Forties Sandstone Member.
Thickness: Over 500 m in parts of the Outer Moray Firth area (e.g. 15/18-2, 15/19-4).
Geographical Limits: The Mey Sandstone Member occurs over most of the Outer Moray Firth and extends southeastwards into the Central Graben. The western limit of the Mey Sandstone Member is erosional.
Parent Unit: Lista Formation (LIST)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  North Sea well 21/2-1: 2002.5-2356.5 m (6570-7732 ft) below KB. 
Reference Section  North Sea well 14/25-1: 1706.5-2154.5 m (5599-7068 ft). 
Reference Section  North Sea well 21/10-7: 2555-2675 m (8383-8776 ft). 
Reference(s):
Knox, R W O'B and Holloway, S. 1992. 1. Paleogene 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. 
Jacque, M and Thouvenin, J. 1975.Lower Tertiary tuffs and volcanic activity in the North Sea. In: Woodland, A W. (ed.) Petroleum and the continental shelf of north-west Europe, 455-465. Applied Science Publishers, London. 
Jolley, D W and Morton, A C. 1992. Palynological and petrological characterization of a North Sea Palaeocene volcaniclastic sequence. Proceedings of the Geologists'Association 103, 119-127. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable