Textures and fabrics in the Dome F (Antarctica) ice core

Abstract

A comprehensive study of ice-crystal fabrics and textures was conducted on the Dome F (Antarctica) ice core. Crystal c-axis orientations, crystal sizes and crystal shape were measured on thin sections with an automatic ice-fabric analyzer. The general feature of textural and fabric development through a 2500 m long core was obtained by a 20 m interval study. Crystal size steadily increases with depth except for depths of about 500, 1800, 2000, 2200 and 2300 m, at which depths crystal size decreases suddenly. There is a clear correlation between crystal-size and δ18O values. Crystals tend to elongate horizontally with depth, and the aspect ratio (long axis vs short axis of a grain) increases two-fold at 1600 m depth and fluctuates below that depth. The c-axis orientation fabrics gradually change with depth from a random orientation pattern near the surface to a strong vertical single maximum at 2500 m. These are very similar to those from the GRIP (Greenland) core. The observations of crystal shape and the fabric measurements indicate that nucleation-recrystallization does not take place at Dome F.