The build-up, configuration, and dynamical sensitivity of the Eurasian ice-sheet complex to Late Weichselian climatic and oceanic forcing
ForfatterPatton, Henry; Hubbard, Alun Lloyd; Andreassen, Karin; Winsborrow, Monica; Stroeven, Arjen P.
The Eurasian ice-sheet complex (EISC) was the third largest ice mass during the Last Glacial Maximum (LGM), after the Antarctic and North American ice sheets. Despite its global significance, a comprehensive account of its evolution from independent nucleation centres to its maximum extent is conspicuously lacking. Here, a first-order, thermomechanical model, robustly constrained by empirical evidence, is used to investigate the dynamics of the EISC throughout its build-up to its maximum configuration. The ice flow model is coupled to a reference climate and applied at 10 km spatial resolution across a domain that includes the three main spreading centres of the Celtic, Fennoscandian and Barents Sea ice sheets. The model is forced with the NGRIP palaeo-isotope curve from 37 ka BP onwards and model skill is assessed against collated flowsets, marginal moraines, exposure ages and relative sea-level history. The evolution of the EISC to its LGM configuration was complex and asynchronous; the western, maritime margins of the Fennoscandian and Celtic ice sheets responded rapidly and advanced across their continental shelves by 29 ka BP, yet the maximum aerial extent (5.48 × 106 km2) and volume (7.18 × 106 km3) of the ice complex was attained some 6 ka later at c. 22.7 ka BP. This maximum stand was short-lived as the North Sea and Atlantic margins were already in retreat whilst eastern margins were still advancing up until c. 20 ka BP. High rates of basal erosion are modelled beneath ice streams and outlet glaciers draining the Celtic and Fennoscandian ice sheets with extensive preservation elsewhere due to frozen subglacial conditions, including much of the Barents and Kara seas. Here, and elsewhere across the Norwegian shelf and North Sea, high pressure subglacial conditions would have promoted localised gas hydrate formation.
SiteringPatton H, Hubbard AL, Andreassen K, Winsborrow M, Stroeven AP. The build-up, configuration, and dynamical sensitivity of the Eurasian ice-sheet complex to Late Weichselian climatic and oceanic forcing. Quaternary Science Reviews. 2016;153:97-121
Viser innførsler relatert til tittel, forfatter og emneord.
UAV photogrammetry and structure from motion to assess calving dynamics at Store Glacier, a large outlet draining the Greenland ice sheet Ryan, Johnny C.; Hubbard, Alun Lloyd; Box, Jason E.; Todd, Joe; Christoffersen, Poul; Carr, J. Rachel; Holt, Tom O.; Snooke, Neal A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-06)This study presents the application of a costeffective, unmanned aerial vehicle (UAV) to investigate calving dynamics at a major marine-terminating outlet glacier draining the western sector of the Greenland ice sheet. The UAV was flown over Store Glacier on three sorties during summer 2013 and acquired over 2000 overlapping, geotagged images of the calving front at an ∼ 40 cm ground sampling ...
Processes and dynamics during deglaciation of a polar continental shelf. Examples from the marine-based Barents Sea Ice Sheet Bjarnadottir, Lilja Run (Doctoral thesis; Doktorgradsavhandling, 2012-12-20)The main objective of this PhD thesis was to reconstruct the pattern and main processes of the last deglaciation of the Barents Sea Ice Sheet. The thesis consists of an introductory part and five papers. The conclusions presented in the papers were based on data acquired with a suite of marine geophysical and geological methods, including multibeam-swath bathymetry data, chirp data, airgun and sparker ...
Geophysical constraints on the dynamics and retreat of the Barents Sea ice sheet as a palaeobenchmark for models of marine icesheet deglaciation Patton, Henry; Andreassen, Karin; Bjarnadóttir, Lilja Rún; Dowdeswell, J.A.; Winsborrow, Monica; Noormets, Riko; Polyak, Leonid; Auriac, A.; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-14)Our understanding of processes relating to the retreat of marine-based ice sheets, such as the West Antarctic Ice Sheet and tidewater-terminating glaciers in Greenland today, is still limited. In particular, the role of ice-stream instabilities and oceanographic dynamics in driving their collapse are poorly constrained beyond observational timescales. Over numerous glaciations during the Quaternary, ...