Great Depths Below Us
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Antonio Jordán 2 years, 1 month ago

The Grand Canyon began to form about six million years ago due to the lateral erosion of the Colorado River, when the elevation increased the potential energy of the river course. The river is still actively eroding its bed, bringing out increasingly old rocks. Soils are mostly sandy and sallow, and erosion processes are very intense in the area. Here, biological crusts (lichens, fungi and others) play an important role for soil protection.