 Several times during the Pleistocene glaciations, the lake depression was occupied by a large glacial lobe of the Patagonian Ice Sheet, which formed a series of moraines along its western shore.The lake has an east-west elongated shape with Fresia Island in the middle and two minor peninsulas pointing toward the island, one from the north and one from the south.The lake has a remarkably smooth shoreline, with only one inlet of significance