Abstract Sedimentary sequences of the continental shelf of the eastern Amundsen Sea Embayment in West Antarctica represent records of past outlet glaciers and ice streams. The former flow of ice streams was channelled through glacial troughs, which now form large bathymetric depressions. We therefore selected one of the largest troughs, the Abbot glacial trough in the outer shelf, to analyse its glacial depositional and erosional history, based on horizon-stratigraphy derived from seismic data. Several basement highs channellized the delivery of sediment and controlled the grounded ice sheet in early glacial periods. Both pre-glacial and full glacial seismic facies were identified. Glacially transported and deposited sediments extended the shelf break by 75 km from the pre-glacial shelf-edge. The main Abbot glacial trough contains sediment from confluent ice flows of the Pine Island/Thwaites, Cosgrove and Abbot Glacier systems, as well as smaller contributions from local ice streams emanating from Thurston Island. Sherman Island of Peacock Sound played an important role in the dynamics of the Abbot Glacier by dividing the ice flow into two ice streams, which interfered with the main glacial sediment transport paths from the south. This study contributes to an understanding of the formation of the Amundsen Sea shelf and the extent of past ice sheet advances.

Abstract This chapter describes Lower Jurassic second-order sequences J00 and J10, and their component third-order sequences J1–J6 and J12–J18. Two sequences (J1 and J3) are new, four sequences (J2, J4, J12 and J16) are amended and one sequence (J17) is renamed. A significant unconformity at the base of the J12 sequence (Upper Sinemurian) is present near the base of the Dunlin Group in the North Viking Graben–East Shetland Platform and in the Danish Central Graben, and correlates with an equivalent unconformity around the margins of the London Platform, onshore UK. A marked unconformity at the base of the J16 sequence is recognized in the North Viking Graben and onshore UK, where it is related to structural movements on the Market Weighton High, eastern England. Several levels of carbon enrichment (carbon isotope excursions (CIEs)) and associated geochemical changes tie to J sequences defining maximum flooding surfaces: the Upper Sinemurian CIE equates to the base J6 maximum flooding surface (MFS), the basal Pliensbachian CIE ties to the base J13 MFS, the basal Toarcian CIE relates to the base J17 MFS and the Toarcian Ocean Anoxic Event corresponds with the base J18 MFS.