Preliminary microstructural and microchemical observations on pond and river accretion ice

Scanning electron microscopy and X-ray microanalysis were employed to investigate the morphology of impurities present in pond and river freshwater ice. Several structural features, 0.4 to roughly 1.2 mm in diameter, with distinct morphological characteristics were identified in the pond ice. The features reside both in the interior of the grains as well as at grain boundaries. In river ice, the impurity aggregates were significantly smaller than in the pond ice (the majority with sizes ⪝20 μm) with no particular shape and were concentrated in the grain boundaries.