Structural investigations of snow and ice on core III from the drilling on Verngatferner, Austria, in 1979
The purpose of this study was: To make an attempt at finding a stratification of the snowpack in order to help remove ambiguities in dating the snowlayers by standard methods. To verify the depth at which the transition between firn and ice occurs. Clearly the first goal was missed, the structural information in a temperate firn being strongly smoothed out in time. Interesting details like horizontal ice lenses and layers of "cold snow" however, were revealed. In spite of strong variations of density, gravimetric density PG and ice density PI, computed from point density, are identical for the firn pack between Z = 2.0 m and 6.0 m. p(ice) = 0.522±0.034· 103 kg m- 3. The ice density of 0.8 . 103 kg m-3, the assumed transition between firn and ice, was found to occur at a depth of Z= 19 m. Even at this level, rather important variations in density may be localized. Between Z= 19 m and 21 m, the ice density varies from 0.774.103 to 0.860 . 103 kg m- 3.