Pond Tectonics.

12-28-12 VERMONT: The neighbors arrived yesterday morning to clear the pond again, but were confronted by eight inches of snow, a much more formidable job than the previous day’s work of three inches. We all decided that it would be easier not to clear the entire pond but create a track around the outside by shoveling some snow inwards and some outwards, leaving a mound in the middle and a track around the mound. They had drilled into the ice a few days before this and the thickness was three inches which is OK, but not optimal for a lot of activity.

When they were almost finished, the weight of the snow mountain in the center caused the ice around it to crack, leaving a central ‘island’ which partially sank on one side. Six cracks spread radially outward from the island quite symmetrically. Everyone fled the ice.

Greenish pond water overspread the half of the island that was depressed until it reached its buoyancy point. One small section of the island, that was not awash, actually popped upward along the fracture line and then cracked perpendicularly to the fracture.


The weight of the piled snow in the center of the pond caused a central island to crack and detach from the ice plate and send out radial fractures.


The far side of the central island sank because of its weight allowing the greenish pond water to flood onto the surface soaking and melting some of the snow mound. It stopped sinking when the buoyancy point was reached. On the near side of the island, a small segment of the ice was uplifted has a crack perpendicular to the uplifted margin.

Close up photo of the uplifted segment, with a 'transform fault'.

I couldn’t help but think of analogies to Plate Tectonics. The first one that came to mind was the depression of continental plates by glacial ice allowing the ocean to flood the land. An example of this happening occurred during the melt down after the recent ice age. Huge lakes formed as ice melted but the water remained trapped behind dams of ice and morainal debris. One such lake was Lake Vermont filling the present Lake Champlain and much more of western Vermont. When the dam broke, the fresh, melt water from the lake drained out the present St. Lawrence valley, but because the weight of the ice had depressed the continental plate, which rebounds very slowly, the ocean water back filled the valley creating the Champlain Sea. Whale fossils have been found in the present Lake Champlain region. When the continental plate did ultimately rebound, the sea water drained and was replaced by fresh melt water.

More examples after I do a bit of research.