Mungo National Park includes Lake Mungo an ancient dry lakebed. During the last ice age, Lake Mungo was one of a chain of freshwater lakes strung along the Willandra Creek. As the Australian continent slowly drifted northwards into hotter, drier climes, temperature and climatic conditions continued to change. About 400,000 years ago dry, windy conditions prevailed and the sluggish, meandering Willandra Creek was cut off, forming the Willandra Lake system. Over time the westerly winds shaped the lake and, as the water receded, continued to shape and create a lunette. The lunette consists of layer upon layer of sand and silt deposited over tens of thousands of years.