High-resolution geophysical observations of the Yermak Plateau and northern Svalbard margin : Implications for ice-sheet grounding and deep-keeled icebergs
| Autor: | Emma Sellén, Riko Noormets, Benjamin Hell, Jan Backman, Morten Sölvsten, Jeffrey Evans, Martin Jakobsson, Colm Ó Cofaigh, Julian A. Dowdeswell, Christian Marcussen, Ludvig Löwemark, Matt O'Regan, Kelly A. Hogan |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Archeology
Global and Planetary Change geography geography.geographical_feature_category Plateau ice sheets Geovetenskap och miljövetenskap High resolution Geology Geophysics glacial morphology Seafloor spreading Iceberg Stratigraphy Margin (machine learning) Arctic Ocean Ice sheet Earth and Related Environmental Sciences Geomorphology Ecology Evolution Behavior and Systematics |
| Popis: | High-resolution geophysical evidence on the seafloor morphology and acoustic stratigraphy of the Yermak Plateau and northern Svalbard margin between 79°20′ and 81°30′N and 5° and 22°E is presented. Geophysical datasets are derived from swath bathymetry and sub-bottom acoustic profiling and are combined with existing cores to derive chronological control. Seafloor landforms, in the form of ice-produced lineations, iceberg ploughmarks of various dimensions (including features over 80 m deep and down to about 1000 m), and a moat indicating strong currents are found. The shallow stratigraphy of the Yermak Plateau shows three acoustic units: the first with well-developed stratification produced by hemipelagic sedimentation, often draped over a strong and undulating internal reflector; a second with an undulating upper surface and little acoustic penetration, indicative of the action of ice; a third unit of an acoustically transparent facies, resulting from debris flows. Core chronology suggests a MIS 6 age for the undulating seafloor above about 580 m. There are several possible explanations, including: (a) the flow of a major grounded ice sheet across the plateau crest from Svalbard (least likely given the consolidation state of the underlying sediments); (b) the more transient encroachment of relatively thin ice from Svalbard; or (c) the drift across the plateau of an ice-shelf remnant or megaberg from the Arctic Basin. The latter is our favoured explanation given the evidence currently at our disposal. |
| Databáze: | OpenAIRE |
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