The Contact Zone

Look across the valley at the ridge in the distance and you can see another type of rock that is common in Joshua Tree National Park. This rock is known as Pinto Gneiss and it lies on top of the lighter colored White Tank Granite. Look closely and you can see the actual zone where the White Tank Granite meets the Pinto Gneiss. As the process of erosion or wearing continues, rock on top is broken down, exposing the rock underneath.