| Summary: | Dark dust accumulates on the surfaces of glaciers ablation zones where it aggregates and forms cryoconite. Inorganic content, often silicate minerals, and organic matter, including wind-blown pollen and plant fragments as well as microbes which contributes to the cryoconite’s own ecosystem, compose the aggregates. Due to its dark color cryoconite absorbs solar radiation better than the surrounding ice and produces heat energy. The increased temperature creates depressions in the ice, filling them with meltwater, and forms cryoconite holes with the sediment at the bottom of the depression. Currently, there are different opinions about the way cryoconite influences glaciers. It does reduce the albedo and contributes to the meltwater production, but there still is debate ideas if cryoconite affects the mass balance of the glaciers or not. The observed ages of cryoconite ranges from modern to ancient which depends on where the dated carbon originates from. For this study, cryoconite samples have been collected from the glacier Nigardsbreen in Norway. One of the samples was decided to be radiocarbon dated and was sent to the University of Lund, Sweden, and attained an age varying between 5045 to 4830 cal. yr BP. This study includes a proposal of how to evaluate the composition and the provenance of the sampled cryoconite, both the mineralogical and the organic part. Silicate minerals and microbial life may also be the dominant compounds in cryoconite originating from Nigardsbreen, as for other analyzed samples all around the world. The study will also place the date into a glacier historical and mass-balance context.
|
|---|