Seven glacial cycles in the middle-late Pleistocene of northwest Europe: Geomorphic evidence from buried tunnel valleys

Research Article| March 01, 2011 Seven glacial cycles in the middle-late Pleistocene of northwest Europe: Geomorphic evidence from buried tunnel valleys Margaret A. Stewart; Margaret A. Stewart * Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 1AZ, UK *Current address: Neftex Petroleum Consultants, 97 Milton Park, Abingdon OX14 4RY, UK. Search for other works by this author on: GSW Google Scholar Lidia Lonergan Lidia Lonergan † Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 1AZ, UK †E-mail: l.lonergan@imperial.ac.uk. Search for other works by this author on: GSW Google Scholar Geology (2011) 39 (3): 283–286. https://doi.org/10.1130/G31631.1 Article history received: 30 Jul 2010 rev-recd: 13 Oct 2010 accepted: 23 Oct 2010 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Margaret A. Stewart, Lidia Lonergan; Seven glacial cycles in the middle-late Pleistocene of northwest Europe: Geomorphic evidence from buried tunnel valleys. Geology 2011;; 39 (3): 283–286. doi: https://doi.org/10.1130/G31631.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The deep-ocean marine isotope record and the Antarctic and Greenland ice caps record numerous glacial and interglacial cycles since the middle Pleistocene, and yet evidence for similar numbers of ice-sheet advances over the continent and shallow shelves of northwest Europe is absent. Here, we document seven generations of regionally correlatable subglacial tunnel valleys that record the geomorphic imprint of ice sheets traversing the North Sea basin between ca. 500 and 40 ka, consistent with that predicted by proxy records of glacial and interglacial climate change. Over 180 subglacial tunnel valleys that incise into Pleistocene sediments in the North Sea basin were mapped over ∼60,000 km2 of three-dimensional seismic-reflection data. Using a subset of these data, we identified seven separate episodes of subglacial erosion that can be correlated regionally in the UK sector of the central North Sea. The characteristics of the valley morphologies, orientations, and infill stratigraphy indicate that each set of tunnel valleys formed during a separate ice-sheet advance and retreat cycle. Stratigraphic data suggest that the tunnel valleys formed significantly later than the Brunhes-Matuyama reversal event at 780 ka and before the Last Glacial Maximum (marine isotope stage [MIS] 2; 21 ka). These results imply a more complicated glacial history for northwest Europe and more glaciations than the three-glaciation model traditionally interpreted from the terrestrial record for the past 500 k.y. Our data provide the most complete documentary evidence for repeated advance and retreat of the northwest European ice sheets since the middle Pleistocene, and for the first time indicate that terrestrial ice-sheet advances in the North Sea can be matched in number with the cold events recorded in oceanic and/or ice-core proxies of climate change over the past 500 k.y. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.