Fig. 5.

Sediment succession at site BBR6 (Fig. 1; sediment log is Fig. 13 in [1]), exposing marine sediments (unit A) below fluvial sand (unit B). Note the pillar-like topography of the upper part of the cliff that is due to ravine formation along melting ground-ice wedges, emanating from unit B (ground ice at red arrow). (B) Massive silty clay interbedded with thin fine sand beds and a thicker set of ripple-laminated sand (∼37 m). (C) Massive silty clay with drop-stone (IRD) of 14*9 cm (∼37.7 m). (D) Stacked sequence of ripple through cross-laminated sand, interbedded with thinner beds of massive silty clay (∼45 m). Note organic debris both in clay beds and ripple troughs. Some of this material includes twigs with diameters of 3–5 mm (arrow point to such twigs excavated, lying on the trench bottom). (E) Horizontal surface in dug sediment pits, showing the trend and thus palaeo-flow direction of ripple troughs (drawn arrows; mean direction towards 270°). (F) Unit B planar parallel-laminated sand with out-sized pebbles (two indicated by arrows). Sediment slumped at digging and thus most clearly displays internal structures in wind-weathered, coherent surfaces before excavation.