Meteoric and marine ice crystal orientation fabrics from the Amery Ice Shelf, East Antarctica
journal contributionposted on 2023-05-17, 05:16 authored by Adam TreverrowAdam Treverrow, Roland WarnerRoland Warner, Budd, WF, Craven, M
The northwestern sector of the Amery Ice Shelf, East Antarctica, has a layered structure,due to the presence of both meteoric ice and a marine ice layer resulting from sub-shelf freezing processes. Crystal orientation fabric and grain-size data are presented for ice cores obtained from two boreholes $70 km apart on approximately the same flowline. Multiple-maxima crystal orientation fabrics and large mean grain sizes in the meteoric ice are indicative of stress relaxation and subsequent grain growth in ice that has flowed into the Amery Ice Shelf. Strongly anisotropic single-maximum crystal orientation fabrics and rectangular textures near the base of the $200 m thick marine ice layer suggest accretion occurs by the accumulation of frazil ice platelets. Crystal orientation fabrics in older marine ice exhibit vertical large circle girdle patterns, influenced by the complex stress configurations that exist towards the margins of the ice shelf. Post-accumulation grain growth and fabric development in the marine ice layer are restricted by a high concentration of brine and insoluble particulate inclusions. Differences in the meteoric and marine ice crystallography are indicative of the contrasting rheological properties of these layers, which must be considered in relation to large-scale ice-shelf dynamics.
Publication titleJournal of Glaciology
Department/SchoolInstitute for Marine and Antarctic Studies
PublisherInt Glaciol Soc
Place of publicationLensfield Rd, Cambridge, England, Cb2 1Er
Rights statementCopyright © 2010 IGS