Sand veins and wedges in cold aeolian environments.
Sand veins and wedges in cold aeolian environments.
Abstract Sedimentary structures formed by the progressive primary infilling of thermal contraction cracks with sand are termed primary sand veins and sand wedges. Primary sand wedges form widely in sandy polar deserts, locally in sandy areas of tundra and probably in seasonally frozen ground. There are no unique criteria for distinguishing primary sand veins and wedges from sand veins and wedges of other origins. Identification of the former depends on the occurrence of distinctive features not always present and on evaluation of their lithofacies and palaeoenvironmental contexts.