Stone roundness of moraines connected with Taku Glacier, southeastern Alaska

Abstract

The roundness and flatness (Cailleux's indices) of granodioritic stones from three different moraines in contact with Taku Glacier were measured. Mean roundness of talus material was 60, of late Wisconsin moraine material 240 and of push moraine material 370. Flatness of stones decreased in the same order. Results were statistically evaluated and the differences were identified also by analysis of variance. By comparing the stone size and roundness it was concluded that the original forms of stones determine their final forms. Flat and small stones cannot be rounded as easely as cubical and bigger blocks by glacial and glaciofluvial processes.