Lake Abert - Ancient Lake Chewaucan

Ancient Lake Chewaucan

The arid land around Lake Abert was once lush. During the Pleistocene epoch, vast areas of south-central Oregon were covered by lakes and wetlands. As the last ice age was ending, rain and runoff from melting snow filled the lowlands throughout this region of the Great Basin, creating an immense, freshwater lake called Lake Chewaucan. The lake covered 461 square miles (1,190 km2) at depths of up to 375 feet (114 m).

Lake Chewaucan covered the Abert and Summer Lake basins for most of the late Pleistocene epoch. The last high water period occurred about 13,000 years ago. There is no archaeological evidence of human utilization of Lake Chewaucan during this time. The earliest evidence for possible human occupation of the basin comes from the Paisley Caves excavated by Luther Cressman in the late 1930s. Cressman found some inconclusive evidence that humans could have begun occupation of the area around 11,000 years ago.

Lake Chewaucan began to dry up at the close of the Pleistocene epoch. As it shrank, salts and alkali were concentrated in its remaining waters, the result was the formation of Lake Abert and Summer Lake. Today, the two lakes are separated by twenty miles, and are the only remnants of Lake Chewaucan.