Historical fluctuations of the Matusevich Ice Shelf, Severnaya Zemlya, Russian High Arctic

Dramatic retreat of ice shelves in Antarctica in recent years, linked to climatic warming, is well documented. In contrast, the ice shelves of the Russian Arctic remain largely unstudied. A time-series analysis of the largest ice shelf in the Russian High Arctic, the Matusevich Ice Shelf, Severnaya Zemlya, was undertaken for the period 1931 to 1994 using georeferenced Landsat satellite imagery and published maps. The positions of three major ice margins in 1931, 1955, 1962, 1973, 1985, 1988, and 1994 are compared. The floating margin of the ice shelf underwent at least two cycles of retreat followed by periods of advance between 1931 and 1994. These periodic calving events produce tabular icebergs up to several kilometers in length. This process is typical of floating ice shelves in Antarctica and Greenland, whereas grounded ice margins in, for example, Svalbard, produce smaller icebergs much more frequently. There is little evidence that these calving events are related to climate change. Landsat imagery is also used to track the movement of 50 icebergs identified in 1985 imagery of Matusevich Fjord. Iceberg release from the fjord between 1985 and 1994 was extremely slow, with 48 of the icebergs observed in 1985 still trapped in the fjord in 1994. The icebergs from Matusevich Ice Shelf remain in the fjord for many years, probably due to either grounding on submarine moraines or trapping by shore-fast sea ice. Much of the sediment load of the trapped icebergs may be melted out and: deposited beneath the sea-ice cover of Matusevich Fjord, and little iceberg-rafted debris of heterogeneous grain size will be transported to the Laptev Sea.