An Extended Climate Archive from the Eastern Alps: The Mt Ortles Ice Cores

Oxygen and hydrogen stable isotopes have been widely used in ice cores as temperature proxies for the last 50 years. In autumn 2011 three ice cores were drilled down to bedrock on the Alto dell'Ortles glacier (3859 m a.s.l.), Eastern Alps. The ice core chronology, based on lead-210 in the upper part and on carbon-14 measurements for the lower part, proves that this record is the most extended of the Eastern Alps and the second most extended ice core record from the Alpine region, extending beyond 7000 years BP. The long temporal extension of this glacial archive represents a unique opportunity to study the climate of the past in this part of the Alps, normally characterized by low-elevation shallow glaciers, whose have been particularly affected by the recent warming. The oxygen and hydrogen isotopic composition was measured for all the three cores and an isotope stacked record was created combining the three isotope profiles. The composite record shows a long warm period during the mid holocene, followed by a decreasing trend extending until the roman period. A large negative anomaly is present during the last 500 years, suggesting the presence of a colder period which was interrupted only in the XX century.