Figure 2. Naust Formation stratigraphy.

For location, see Fig. 1. The Naust Formation is composed of Late Pliocene to Pleistocene sediments that form a thick succession of prograding sediment wedges and sheet-like units, which are mainly of glacial origin. The formation commonly down-laps onto the deltaic Kai and Molo (M) formations, as well as the Helland Hansen Arch (HHA). It is divided into five dated sequences (N, A, U, S and T) based on the limited availability of high-quality core. White writing shows the ages for the base of each package, although the dating is particularly uncertain for the older packages³,⁵⁹,⁶⁰. The red line shows the stratigraphic location of the palaeo-seafloor (Fig. 3) investigated here. The seismic profile is 70 times vertically exaggerated to illustrate large-scale margin architecture. Vertical axis is two-way travel (TWT) time. In water, 1 s TWT≈0.75 km, assuming a sound velocity of 1.5 km s⁻¹; in sediments, 1 s TWT≈1 km, assuming a sound velocity of 2 km s⁻¹.