Tag Archives: Monolith

Twin Sisters at City of Rocks National Reserve

At City of Rocks National Reserve in Malta, ID we hiked up to the saddle between the twin sisters, then explored each monolith to determine lithology. The south sister (on the left as we approach) is 2.5 Ga granite pluton; the north sister is a much younger 28 Ma granite pluton that intruded the older rock. This footage was shot by GoPro cameras.