Transcript for Drift Ice as a Geologic Agent, segment 07 of 11


{{{Frazil & Slush Ice}}}

The first growth of ice often occurs when freezing temperatures and strong winds lead to supercooled water. Here, small ice crystals called frazil grow. Frazil eventually rises to the surface to form layers of slush which slowly congeals into solid ice. Sometimes accumulations of slush ice the consistency of applesauce are driven against the shore face, agitated by waves. The setting here seems benign as far as sediment dynamics are concerned, as the waves have a very short, two-second period and are only ten to twenty centimeters high. However, we observed that the slush layer was at least ninety-five centimeters thick and so viscous that its oscillation caused the feet to slide back and forth, caused cobbles to strike the ankles, and form twenty centimeter high ripples on the gravelly seabed.

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