Blue Lake

The Blue Lake is a large, monomictic, crater lake located in a dormant volcanic maar associated with the Mount Gambier maar complex. The lake is situated near Mount Gambier in the Limestone Coast region of South Australia, and is one of four crater lakes on Mount Gambier maar. Of the four lakes, only two remain, as the other two have dried up over the past 30 to 40 years as the water table has dropped.

Conflicting dates have been estimated for its last eruption, of 4,300 years ago, of 28,000 years ago, and most recently, a little before 6,000 years ago. If the youngest date is correct, this could be the most recent volcanic eruption on the Australian mainland.