Dynamics and GPR stratigraphy of a polar rock glacier on James Ross Island, Antarctic Peninsula

• Main Authors: Fukui, K., Sone, T., Strelin, J.A., Torielli, C.A., Mori, J., Fujii, Y.
• Format: Journal/Newspaper
• Language: English
• Subjects: basal ice; data processing; debris flow; field method; geodesy; glacier dynamics; ground penetrating radar; polar region; rock glacier; stratigraphy; valley glacier; Antarctic Peninsula; Antarctica; James Ross Island; West Antarctica; Antarc*; Antarctic; ice core; Ross Island
• Online Access: https://hdl.handle.net/20.500.12110/paper_00221430_v54_n186_p445_Fukui

We describe field measurements (ground-penetrating radar (GPR), geodetic survey and ice-core drilling) to provide new information on the movement mechanism and internal structure of a polar rock glacier on James Ross Island, Antarctic Peninsula. We collected GPR data along longitudinal and transverse profiles. The longitudinal GPR profiles identify inter-bedded debris-rich layers that dip up-glacier, similar to the thrust structures in the compression zone of a valley glacier. The transverse GPR profiles indicate a syncline structure inclined towards the central part of the rock glacier, resembling the transverse foliation of a valley glacier. The stratigraphy of two boreholes shows that the rock glacier consists primarily of bubbly ice with thin debris-rich layers, an internal structure similar to the 'nested spoons' structure common in the interior of valley glaciers. These results indicate that the glacier motion is controlled by shear movement, common in valley glaciers. The geodetic survey confirms that flow velocities decrease towards the lower part of the rock glacier. Such heterogeneous movement causes longitudinal compression and forms thrusts which then create the debris-rich layer by uplifting basal ice and debris. Pushing of the upstream ice against the downstream ice bends the surface layers, forming transverse ridges on the rock glacier surface. Fil:Strelin, J.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.