Four million years ago, the Colorado River started to enter into the area, and the formation of the Colorado River Delta separated the Salton Trough during the Pleistocene from the Gulf of California; during the Pliocene the connection still existed.
The Colorado River started to enter into the area. This was four million years ago. The formation of the Colorado River Delta separated the Salton Trough during the Pleistocene from the Gulf of California. This was four million years ago. The connection still existed. This was during the Pliocene.