Sedimentary architecture and landforms of the late Saalian (MIS 6) ice sheet margin offshore of the Netherlands

[摘要] Reconstructing the growth and decay of palaeo-ice sheetsis critical to understanding the relationships between global climate andsea-level change and to testing numerical ice sheet models. In this study,we integrate recently acquired high-resolution 2D seismic reflection andborehole datasets from two wind-farm sites offshore of the Netherlands toinvestigate the sedimentary, geomorphological, and glaciotectonic recordsleft by the Saalian Drenthe substage glaciation, when Scandinavian land icereached its southernmost extent in the southern North Sea (ca. 160 ka,Marine Isotope Stage 6). A complex assemblage of glaciogenic sediments andglaciotectonic structures is buried in the shallow subsurface. The northernwind-farm site revealed a set of NE–SW-oriented subglacial meltwater channelsfilled with till and glaciofluvial sediments and an E–W-trending compositeridge with local evidence of intense glaciotectonic deformation that denotesthe maximum limit reached by the ice. Based on the identified glacialgeomorphology, we refine the mapping of the maximum ice sheet extentoffshore, revealing that the ice margin morphology is more complex thanpreviously envisaged and displaying a lobate shape. Ice retreat left anunusual paraglacial landscape characterised by the progressive infilling oftopographic depressions carved by ice-driven erosion and a diffuse drainagenetwork of outwash channels. The net direction of outwash was to the westand southwest into a nearby glacial basin. We demonstrate the utility ofoffshore wind-farm data as records of process–form relationships preserved inburied landscapes, which can be utilised in refining palaeo-ice sheetmargins and informing longer-term drivers of change in low-relief settings.

[学科分类] 土壤学