Lichenometric Dating, Lichen Population Studies and Holocene Glacial History in Tröllaskagi, Northern Iceland

In view of the problems of lichenometric dating as applied in northern Iceland, studies of populations of Rhizocarpon geographicum s.1. are advocated in addition to using largest thalli alone as a measure of age. It is concluded that such studies can provide a supporting dating method for the last two centuries and also indicate the presence of disturbed lichen populations. ‘Traditional’ lichenometric dating of recent end moraines in Tröllaskagi confirms that there were five periods of moraine abandonment: A.D. 1810–1820; 1845–1875; late 1880s-early 1890s; 1915–1925; late 1930s-early 1940s. Inorderto extend moraine dating beyond the lichenometric timescale (pre-A.D. 1800) it is argued that greater emphasis will have to be placed on surrogate climatic records from peats and lake sediments which can be dated by other methods.