EBSD analysis of subgrain boundaries and dislocation slip systems in Antarctic and Greenland ice

• Main Authors: Weikusat, Ilka, Kuiper, Ernst-Jan N, Pennock, Gillian M, Kipfstuhl, Sepp, Drury, Martyn R
• Format: Dataset
• Language: English
• Published: PANGAEA 2017
• Subjects: AWI_Glac; DEPTH; ice/snow; EDML; EDRILL; Elevation of event; EPICA-Campaigns; EPICA drill; EPICA Dronning Maud Land; DML28C01_00; Event label; File content; File name; File size; Glaciology @ AWI; Greenland; ICEDRILL; Ice drill; Kohnen Station; Latitude of event; Longitude of event; NEEM; Uniform resource locator/link to file; Antarctic; Dronning Maud Land; Kohnen; Antarc*; Antarctica; DML; EPICA; ice core; Journal of Glaciology
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.879614; https://doi.org/10.1594/PANGAEA.879614

Ice has a very high plastic anisotropy with easy dislocation glide on basal planes while glide on non-basal planes is much harder. Basal glide involves dislocations with Burgers vector b= , while glide on non-basal planes can involve dislocations with b= , b=[c] and b=<c+a>. During natural ductile flow of polar ice sheets most of the deformation is expected to occur by basal slip accommodated by other processes including non-basal slip and grain boundary processes, however the importance of different accommodating processes is controversial. The recent application of micro-diffraction analysis methods to ice such as X-ray Laue diffraction and electron backscattered diffraction (EBSD) has demonstrated that subgrain boundaries indicative of non-basal slip are present in naturally deformed ice, although, so far the available data sets are limited. In this study we present an analysis of a large number of subgrain boundaries in ice core samples from one depth level from two deep ice cores, from Antarctica (EPICA-DML deep ice core at 656 m depth) and from the Greenland (NEEM deep ice core at 719 m depth).