how old are columbia river rocks
The Geologic Story of the Columbia Basin. The rock formations of the Columbia Basin were formed by some of the most unusual and catastrophic processes in geologic history. Early History - 40-60 million years ago: During the early stages of the Columbia Basin formation, granite rock was slowly created by heat and pressure deep in the crust of the earth. Then the crust was uplifted, exposing the granite, creating mountains similar to the Okanogan Highlands north of Grand Coulee Dam.