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Here's one idea how they might be formed... There is a zone of sand running parallel to the water line that is above the Lake water level but gets drenched as each wave wash up the beach. Between waves the water percolates down through the sand until it reaches Lake level leaving the sand above it damp but not saturated. When the next wave comes air that is present within this layer of sand bubbles up, forming sort of a sand tube (about the diameter of a pencil). These tubes are sometimes aggregated in patches that are similar size to the ice form in the photos. It looks like at certain temperatures, water in the bubble tubes can freeze while the water in the sand surrounding the tubes stays liquid. Maybe the bubbles of air cause enough air exchange in the tubes that only this water reaches the freezing point while water present within the sand outside the tubes is warmer. The sand around the patch of frozen bubble tubes could get washed away leaving the ice form exposed. I wonder if there is a column of air in the center of the little ice pillars within the ice form?
Pete
Peter J. Badra
Aquatic Ecologist Michigan Natural Features Inventory Michigan State University Extension Stevens T. Mason Building PO Box 30444 Lansing, MI 48909-7944 office: (517) 241-4179 fax: (517) 373-9566 email: badrap@michigan.gov www.msue.msu.edu/mnfi >>> Richard L Whitman <rwhitman@usgs.gov> 12/14/2005 3:13 PM >>> Kystal Potts at our station took these pictures on the beach yesterday. They are quite unusual formations. Does anybody know how they are formed. Richard Whitman Research Ecologist/Station Chief Lake Michigan Ecological Research Station 219-926-8336 Ext. 424 1100 North Mineral Springs Road Porter, IN 46304 ----- Forwarded by Richard L Whitman/BRD/USGS/DOI on 12/14/2005 01:35 PM -----
I have never been to the beach in the winter time, so I was pretty amused by these ice sculptures along the shoreline. I can't wait to see some shelf-ice. Krystalynn Potts U. S. Geological Survey 1100 N. Mineral Springs Rd. Chesterton, IN 46304-1225 Tel: 219-926-8336, ext 445 Fax: 219-929-5792 Email: kpotts@usgs.gov |