TY  - JOUR
A1  - Weikusat, Ilka
A1  - Miyamoto, Atsushi
A1  - Faria, Sergio H.
A1  - Kipfstuhl, Sepp
A1  - Azuma, Nobuhiko
A1  - Hondoh, Takeo
T1  - Subgrain boundaries in Antarctic ice quantified by X-ray Laue diffraction
Y1  - 2011
VL  - 57
IS  - 201
SP  - 111
EP  - 120
JF  - Journal of Glaciology
DO  - 10.23689/fidgeo-2783
N2  - Ice in polar ice sheets undergoes deformation during its flow towards the coast. Deformation and recrystallization microstructures such as subgrain boundaries can be observed and recorded using high-resolution light microscopy of sublimation-edged sample surfaces (microstructure mapping). Subgrain boundaries observed by microstructure mapping reveal characteristic shapes and arrangements. As these arrangements are related to the basal plane orientation, full crystallographic orientation measurements are needed for further characterization and interpretation of the subgrain boundary types. X-ray Laue diffraction measurements validate the sensitivity of different boundary types with sublimation used by microstructure mapping for the classification. X-ray Laue diffraction provides misorientation values of all four crystal axes. Line scans across a subgrain boundary pre-located by microstructure mapping can determine the rotation axis and angle. Together with the orientation of the subgrain boundary this yields information on the dislocation types. Tilt and twist boundaries composed of dislocations lying in the basal plane, and tilt boundaries composed of nonbasal dislocations were found. A statistical analysis shows that nonbasal dislocations play a significant role in the formation of all subgrain boundaries.
UR  - http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/7096
ER  -