International Geologiical Congress - Oslo 2008

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CGC-13 Fjords: climate and environmental change

 

Long-term morphodynamic evolution of a fjord formed by tidewater glaciers in Svalbard

 

Suzanne MacLachlan, Scottish Association for Marine Science (United Kingdom)
John Howe, Scottish Association for Marine Science (United Kingdom)
 

 

At high latitudes, sediment transport beneath ice sheets is an important mechanism for transferring sediment from the continental interior to the coastal fringes and beyond. We present new fjord bathymetry data to characterise the evolution of the fjord physiography and the glacio-sedimentary processes since the Last Glacial Maximum (LGM). Swath bathymetry from the near-shore environment of Kongsfjorden shows an assemblage of submarine landforms produced by glacial advance and retreat. A series of several styles of landform were identified, frequently superimposed upon one another, permitting the reconstruction of the relative timings of deposition of each landform, with the oldest successively overlain and cross-cut by younger landforms and erosional processes. Large transverse ridges interpreted as recessional moraines are overlain by streamlined lineations formed subglacially during a subsequent ice advance. An assemblage of recessional morainal ridges within the central fjord are incised by glacial lineations and meltwater channels from younger deglacial events. Furthermore, the observed current erosion of the seabed has been integrated with oceanographic mooring data to estimate current erosion rates since the LGM.

 

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