Difference between revisions of "North Berwick Pyroclastic Member"
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North Berwick Pyroclastic Member is part of the the Garleton Hills Volcanic Formation
Previously named the North Berwick Member (see McAdam and Tulloch, 1985).
The North Berwick Pyroclastic Member consists of green (lower part in the north) and red (all in the south) tuffs, lapilli-tuffs and agglomerate locally with sedimentary intercalation of a lacustrine limestone, the Sunnyside Limestone, up to 2.9 m thick. These are commonly well bedded and waterlain and interbedded with volcaniclastic sedimentary rocks including thin dolostones and siliciclastic mudstones with sandstones showing ripple marks.
The type area is East Lothian (NT 4500 6900 to 6300 8500) around North Berwick, East Linton, the Garleton Hills, and Stenton (see Davies et al., 1986, fig. 10; McAdam and Tulloch, 1985, fig. 17). Complete reference sections are provided by the IGS East Linton 2 Borehole (BGS Registration Number NT57NE/2) (NT 59664 77091) from about 48.8 to 104.2 m depth, and the Spilmersford Borehole (BGS Registration Number NT46NE/73) (NT 4570 6902) from about 476 to 544 m depth.
Lower and upper boundaries
The base is conformable on the underlying Ballagan Formation (Inverclyde Group). The change is transitional by interbedding of tuff and lapilli-tuff into the underlying siliciclastic and carbonate rocks.
The member is overlain by the basaltic lavas of the East Linton Lava Member to the south of the Dunbar–Gifford Fault where the somewhat younger siliciclastic Gullane Formation rests directly on it. The contact is conformable and locally unconformable.
Between 0 and 220 m
Distribution and regional correlation
East Lothian, outcrop of the Garleton Hills Volcanic Formation around North Berwick, East Linton, Garleton Hills, Stenton and in the subcrop farther west in the BGS Spilmersford Borehole (see above) near Pencaitland, and south to the Lammermuir Fault.
Early Visean (Chadian to Arundian
- McAdam, A D, and Tulloch, W.1985.Geology of the Haddington district.Memoir of the British Geological Survey, Sheet 33W, part 41 (Scotland).
- Davies, A, McAdam, A D, and Cameron, I B.1986.Geology of the Dunbar district.Memoir of the British Geological Survey, Sheet 33E and part of Sheet 41 (Scotland)