The densification and diagenesis of snow

The Greenland and Antarctic Ice Sheets are monomineralic rock formations, primarily metamorphic, but with sedimentary veneers . The metamorphic part consists of glacier ice that has been metamorphosed primarily by flow caused by unbalanced stresses. The sedimentary veneer has a maximum thickness of about 90 meters and consists of snow and firn. This paper is concerned with diagenetic processes occurring within the sedimentary veneer, causing evolution of loose snow to glacier ice. This diagenesis constitutes one step in the over-all balance between accumulation at the snow surface and loss of ice by flow within the metamorphic part of the ice sheet. Although the discussion is based partly on field observations from Greenland, it deals with the general problem of snow densification; indeed, the results are not completely limited to rocks composed of ice but apply in part to the over-all diagenesis of unconsolidated sediments into consolidated sedimentary rock.