Determining the grain geometry from ultrasonic measurements of large-grained temperate ice cores

Ice shelf collapse significantly contributes to the global rise of sea levels. This intricate process of fracturing, though not yet fully understood, is intertwined with the mechanical attributes of ice. Among the critical physical attributes related to its mechanical characteristics is the crystal orientation fabric (COF), which encapsulates the dimensions, orientations, and inclinations of the constituent crystal grains within the ice structure. The acquisition of such granular information necessitates the extraction of ice cores from the ice sheets or shelves, followed by their transportation to a controlled laboratory environment. After this, these cores are sectioned into submillimetre slices and examined using polarised light microscopy (PLM). However, this procedure destroys the ice core specimens and only permits the acquisition of two-dimensional images, imparting only a partial depiction of the three-dimensional COF.The principal objective of this work is to explore the possibility of involving ultrasound technology to discern the crystal grains' COF and their geometries. This novel approach does not harm the sample material during the examination.