Title: Thin Section Analysis of the WAIS Divide Deep Ice Core
Author: Fitzpatrick, J.J., Hong, I., Laurel, D., Fegyveresi, J.M., Spencer, M.K., Alley, R.B. and Fudge, T.J.
Periodical: American Geophysical Union, Fall Meeting 2011, abstract #C21A-0456

The WAIS (West Antarctic Ice Sheet) Divide deep ice core offers a new window on the internal structure of the West Antarctic ice sheet. Thin-section analyses using high-resolution digital photography followed by image processing and analysis are yielding interesting results. Grains in the upper portions of the core above 580 m exhibit normal grain growth behaviors (linear increase of mean grain area with time, Fig. 1) with growth being primarily attributable to grain-boundary migration. In this same zone, interactions between bubbles and migrating grain boundaries appear to be quite strong, and frequently exhibit evidence of Zener pinning which possibly produces new grains. Interactions of impurities with grain boundaries also appear to be strong, with grain-size layering beginning about 2600 m in the core apparently delineating annual layers. Grain-size trends with depth and age show considerable structure. Analyses are ongoing, and additional results will be discussed.

Year: 2011