Enhanced rockfall activity during the Little Ice Age: Further lichenometric evidence from a Norwegian talus

A recent study of lichen sizes on a talus in western Norway suggested that rockfall frequency was enhanced considerably during the cold conditions of the Little Ice Age. That conclusion is tested here using another talus in w estern Norway, in an area where lichen (genus Rhizocarpon) growth rates are higher. That part of the talus retaining a late Holocene record yields a l ichen size- frequency distribution quite different to that reported in the previous study. However, when the appropriate lichenometric dating curve is used within a model that simulates the influence of late Holocene rockfall activity on lichen size-frequency distributions, a similar temporal patter n of rockfall supply is obtained. The results suggest that, at this site, r ockfall frequency during the eighteenth century, the coldest phase of the L ittle Ice Age, may have been up to seven times higher than the normal late Holocene rate. Copyright (C) 2001 John Wiley & Sons, Ltd.