Laboratory studies of flow properties and associated crystal structure in Holocene and Wisconsin ice

TL;DRAbstract

Ice mechanical experiments in uniaxial compression and in simple shear configurations were carried out at 0.2 MPa octahedral shear stress and - 5 °C on ice core samples deposited as snow during the Wisconsin and Holocene periods. Tested samples were selected from ice cores drilled in South Greenland (Dye 3), Ellesmere Island, Canada (Agassiz Ice Cap) and East Antarctica (Law Dome Ice Cap), with an aim to finding the reasons for different flow rates between Wisconsin ice and Holocene ice. These different flow rates, reported by some glaciologists, were inferred from field measurements of borehole closure and inclination. The ice test samples were analysed for crystal size and orientation fabric, and soluble and insoluble impurity concentrations. The experiments, in two different stress configurations, gave coincident results. With the progression of strain, the deformation of the Wisconsin ice and of the Holocene ice tended to reach a constant tertiary (steady state) flow rate. Ice

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