Northumberland Field Trip

The trip will be based in Berwick-on-Tweed and will visit localities in some of the spectacular coastal and inland scenery of the area. It will illustrate the varied infill of the Tweed Sub-basin in Late Devonian and early Carboniferous times. The trip will illustrate not just the local succession, which is widely applicable as a direct analogue across a wide swathe of the southern North Sea, but also a range of fluvial and deltaic facies and facies geometries that are generally applicable in a much wider range of settings. The fluctuating sea-level that characterised much of the Carboniferous makes the Northumberland succession an excellent place to discuss the impact of these controls in terms of sequence stratigraphic principles.      

The trip will begin at the spectacular and iconic Hutton’s Unconformity at Siccar Point. The overlying Old Red Sandstone of Peace Bay shows a variety of alluvial styles and facies that have relevance to fluvial reservoirs of other ages in other basins. The Cementstones at Burnmouth show a contrasting fluvial style with point bar sands, crevasse splays and lacustrine interbeds indicating a lower gradient, more humid fluvial regime. Above the Cementstones, the widespread fluvial channel complex of the Fell Sandstone, seen best inland at Bowden Doors, shows a further change of fluvial style to a major sandy braid plain with staked channel sandbodies. The sandstones internally show a spectacular assemblage of sedimentary structures including descending cross-beds, overturned cross bedding and slump plugs.

The overlying Scremerston Coal Formation will only be seen in its uppermost part at Spittal, just south of Berwick, where its upwards passage into the Lower Limestone Formation at the Duns Limestone is followed by a major channel sandbody interpreted as a palaeovalley fill. The probably correlative sandbody will also be seen at Marshall Meadows some 5 miles distant where the lateral extent and internal organisation of the channel complex is well seen in the context of Yoredale cycles. The Middle Limestone Formation at Howick shows a beautifully exposed upwards-coarsening deltaic progradation that is strongly influenced by wave and storm generated structures  whilst the Upper Limestone Formation on the southern side of the Howick Fault shows a complex channelling  within delta-plain sediments and a major channel complex thought to be another palaeovalley fill.

NB: For safety reasons a maximum of 14 places are available.  If you are interested in attending please contact julie@pesgb.org.uk