Anomalous Behaviour of Antarctic ice Cores Studied by Electrical and Mechanical Damping Measurements

Abstract

In order to obtain new information concerning the anomalous properties of Antarctic ice previously observed through electrical measurements, we have studied specimens from a coastal site by means of internal friction measurements in the 1 Hz range. The results have been compared to previous ones obtained with polar ice from Dome C and electrical measurements have been made on the same samples in order to confirm the anomalous behaviour of such material.Two possible explanations of the anomalous properties of polar ice are discussed, namely the role of impurities and the ageing effect. It seems improbable that impurities could be responsible for such properties due to their low concentration. Some experiments, however, lead us to interpret the behaviour of polar ice in terms of modifications with time of the concentration and distribution of intrinsic point defects present at the beginning of the existence of the ice microcrystals. INTRODUCTION Previous work has shown that the electrical prop-