Abstract
Eskers have been used to infer the dynamics and palaeo-hydrology of large ice sheets yet there are few suitable contemporary analogues for esker sedimentation during Quaternary glaciations. Consequently, models of esker sedimentation have been derived from morpho-sedimentary analyses of Quaternary eskers, but these lack rigorous constraints on their depositional timescales. We identify the controls on the large-scale sedimentary architecture of a large (>700 m long, 10°) inclined reflections, interpreted as backset accretion associated with large-scale bedform development; (4) down-flow dipping high-angle (>15°) inclined reflections, interpreted as foreset accretion associated with macroform progradation; (5) quasi-hyperbolic reflections, interpreted as zones of boulder clustering; and (6) zones of enhanced noise and EM signal attenuation, bounded on the upper surface by a continuous reflection sub-parallel to the ground surface, interpreted as buried ice associated with the conduit/channel base. These data suggest that deposition took place within a non-uniform englacial conduit, which has resulted in major up-flow to down-flow variations in sedimentary architecture. The complexities observed are a direct consequence of variations in sediment supply and the within-event evolution of conduit geometry. This study provides the first detailed insight into the large-scale sedimentary architecture of a single event jökulhlaup proto-esker.
Original language | English |
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Pages (from-to) | 1829-1847 |
Journal | Quaternary Science Reviews |
Volume | 27 |
Issue number | 19-20 |
DOIs | |
Publication status | Published - 2008 |
Keywords
- paleohydrology
- quaternary
- ice sheets
- sedimentation analysis