Nineteenth- and Twentieth-Century Glacier Fluctuations and Climatic Implications in the Arco and Colonia Valleys, Hielo Patagónico Norte, Chile

Dendrochronology, lichenometry, and analysis of aerial photographs taken in 1944, 1979, and 1983 were used to date the 19th- and 20th-century fluctuations of the Arco, Colonia, and Arenales glaciers on the eastern side of the Hielo Patagónico Norte in southern Chile. This work has demonstrated that the glaciers retreated from their Little Ice Age maximum positions between 1850 and 1880, with retreat rates increasing during the 1940s and with surface thinning of at least 30 m since 1980. Comparison with the fluctuation behavior of other outlet glaciers of the icefield suggests a degree of synchrony in the timing of their variations and therefore argues for a common climatic control for these movements.