Potential to recover climatic information from scandinavian ice cores: an example from the small ice cap riukojietna

Abstract

ABSTRACT. We have studied a 33.7 m deep ice core from a small polythermal Scandinavian ice cap to determine whether it is possible to recover pre‐20th century climatic information from the glacier. Ice structural studies show a significant change from clear ice above 11 m depth (superimposed ice indicating refreezing) to bubbly ice below 11 m depth, indicating this is the transition between Little Ice Age (LIA) and 20th century ice. Calculations with a Nye‐age model, along with a mass balance reconstruction, show that this structural boundary likely formed in the last part of the LIA, which in this region ended about 1910. The ice below this boundary was sampled and analysed for stable isotopic composition and ionic content, which both show significant variations with depth. The stable isotope record likely contains cycles of annual duration during the LIA. The chemistry in the ice core indicates that the information is useful, and can be used to interpret climatic and environmental variables during the LIA. A comparison of Riukojietna ion chemistry and oxygen isotope records with similar records from other glaciers in this region reveals a clear continental‐maritime gradient. Changes in this gradient with time may be possible to resolve using such ice core records. Results from this study demonstrate that ice cores from glaciers in this climatic environment can be useful in revealing environmental conditions from climatically colder periods and yield pre‐industrial benchmark values for chemical loading and oxygen isotopes, but that hiatuses complicate the depth‐age relationship.