Lichenometric Analysis of the Kärkerieppe Slush-Avalanche Fan, Kärkevagge, Sweden

ABSTRACT

Sizes of isolated and fully exposed largest lichens on 950 blocks of schistose rock record the times and extents of slush avalanches derived from a stream channel and cirque upstream from the 300 m long Kärkerieppe fan in Kärkevagge, northern Sweden. Small slush avalanches are so frequent that few blocks older than 50 years remain on the fanhead. At least 13 smaller and larger slush avalanches occurred between 1950 and 1995; a production rate of about 30 per century. At least 24 slush avalanches extended to the mid-fan area between about 1790 and 1950; a mean production rate of large slush avalanches of about 15 per century. “Little Ice Age” advances of the Kärkerieppe cirque glacier ended at about 1870 and may have supplied blocks to slush avalanches. Subsequent glacier retreat has changed the source-area hydrologic and topographic characteristics affecting generation of slush avalanches, and has exposed new bedrock sources of blocks for slush avalanches.