Stratigraphy of a North Sea Tidal Sand Ridge

Abstract

Large sand ridges in the East Bank area of the North Sea lie in deeper water and are subjected to less powerful tidal currents than the better known Norfolk Banks further to the south. They also lack large-scale bedforms on their surfaces. The East Bank ridges are considered to have formed during the early Holocene around 9000 YBP and are now moribund. Drilling of a 35-m thick ridge from this area has shown a remarkably homogenous stratigraphy. The ridge is characterized by 2 stacked, slightly coarsening-upward sequences of fine, well-sorted terrigenous sand. Bioturbation characterizes the top of the sequence with fine laminations and small-scale, ripple cross-strata scattered throughout. Heavy minerals are diverse and increase in abundance upward.