Discontinuous dumps of ice blocks seen along the margin of a high altitude frozen lake is intriguing. Could these be the broken parts of pre-existing wall like structure? Can anyone suggest the origin of these lake margin dumps of ice slabs?
Maybe they are from fractured pieces of the ice cover that get caught between the shore and the main ice sheet when an on-shore wind commences. The main ice sheet cove then drives any free pieces up onto the shore like a glacier in reverse.
There are several possibilities as mentioned by Dr Chinn. Maybe this will help with terminology http://www.lakesuperiorstreams.org/understanding/iceterms.html. Shore ice freezes first, wind and waves, ice sheet expansion and breaking, etc.
Dear Abjihit,
Seems like inverse fault proceses occurred on rocks. Looks like ice expands due to congelation/cristalization and it moves to on-shore forming structures like inverse faults. This process could be repeated during different periods of congelation/descongelation producing these estructures.
Is just an imppresion, because i don't know nothing about ice processes, i'm just a basic geologist.
Have a great day
A slightly informed observation: When I was a pre-teenager living near Lake Decatur at Decatur, Illinois, USA, I saw 2-3 inch thick ice sheets'blocks pushed a meter or two over the dry beach from the waterline. Some simply angled upwards with a large empty space underneath and some were shattered. The lake was perhaps a kilometer wide. That provided enough distance for simple expansion during ice freezing to explain the phenomenon. Fortunately, my friends and I survived the stupid action of climbing over the ridges and walking out on the lake without knowing how thick the ice really was!
Hi Jarrett! Thanks for sharing the story. I would rather call it an act of bravery we won't venture in now :-D
Dear David, actually i thought about that possibility initially. But if you have a look at Hansen's link (and Jarett's story)...you might think otherwise. Perhaps (wind driven) shore-ward thrusting of broken fragments of ice cover appears best to explain these ice blocks. Enechelon blocks, mostly dip towards the lake. Any thermally induced (faults etc) event won't perhaps produce such polarity in the arrangement of these ice blocks.
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