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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.

Item Type:	Refereed Article
Research Division:	Earth Sciences
Research Group:	Physical geography and environmental geoscience
Research Field:	Glaciology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the earth sciences
UTAS Author:	Treverrow, A (Dr Adam Treverrow)
UTAS Author:	Warner, RC (Dr Roland Warner)
UTAS Author:	Budd, WF (Professor William Budd)
UTAS Author:	Craven, M (Mr Mike Craven)
ID Code:	68153
Year Published:	2010
Web of Science® Times Cited:	16
Deposited By:	IMAS Research and Education Centre
Deposited On:	2011-03-09
Last Modified:	2011-05-22
Downloads:	561 View Download Statistics