Sturts Trail – Lake shore
Glacial lake shore
The glacier is mostly ice but contains lots of sands, gravels and rocks (sediment) that it has picked up on its journey to here. As the glacier melts this sediment and water fill the lake. Sometimes large blocks of ice break off from the front of the glacier, float into the lake and get grounded on the bottom of the lake.
Stranded ice blocks
These blocks of ice melt slowly because it is still very cold. The lake keeps filling with sediment from the glacier. This sediment surrounds the base of the block of ice. Eventually the glacier retreats, the lake stops filling, and the water will drain away (slowly not as a big catastrophe). The blocks of ice are now stranded in deep sediment that was once the flat base of the lake.
The ice melts leaving behind depressions that may now fill with water and become Ice Age Ponds.