| Sign In to gain access to subscriptions and/or personal tools. |
Little Ice Age glacier variations in Jotunheimen, southern Norwvay: a study in regionally controlled lichenometric dating of recessional moraines with implications for climate and lichen growth ratesHolocene Research Group, Department of Geography, University of Wales at Swansea, Singleton Park, Swansea SA2 8PP, UK; j.a.matthews{at}swansea.ac.uk A new approach to regional lichenometric dating is developed and applied toLittle Ice Age moraine-ridge sequences on 16 glacier forelands in Jotunheimen, southern Norway. Lichenometric-dating curves, based on the Rhizocarpon subgenus, are constructed independently for west, central and east Jotunheimen. Although there are differences between the subregions, a composite regional moraine chronology for Jotunheimen identifies 12 episodes of moraine formation in AD 1743-1750 (the regionalLittle Ice Age glacier maximum), 1762-1771, 1782-1790, 1796-1802, 1811-1818, 1833-1838, 1845-1854, 1860-1868, 1871-1879, 1886-1898, 1915-1922 and 1927-1934. Spatial and temporal patterns in glacier behaviour between the subregions and between Jotunheimen and the neighbouring Jostedalsbreen are explained in terms of the interaction of annual to decadal variations in summer temperature and winter precipitation: glacier advances and moraine-formation events driven primarily by winter-precipitation variations exhibit subregional patterns while summer-temperature forcing affects more synchronous glacier behaviour across the region. Regionally controlled lichenometric dating improves the accuracy of dating by up to about±20 years on relatively old moraines and is dependent on regional patterns in the rate of lichen growth. On relatively young surfaces, mean cumulative growth rate declines from about 0.75mm yr-1 in maritime west Jotunheimen to about 0.55mm yr-1 in continental east Jotunheimen (though the differential in growth rate is less on older surfaces).
Key Words: Lichenometry Rhizocarpon lichenometric-dating curve lichen growth rates regional control glacier variations Little Ice Age moraine chronology climatic variations decadal scale Jotunheimen Norway
The Holocene, Vol. 15, No. 1,
1-19 (2005) This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
