Kelso Dune Sand - Where did it come from?
Sand is made up of minerals and tiny pieces rock that were once part of another, much larger rock. Over time, the slow processes of weathering and erosion can
turn large rocks into sand. Geologists can often track down the original
source for sand grains by comparing the minerals and other characteristics
of the sand with rocks in mountains nearby.
Most of the sand grains you'll see at Kelso Dunes are
made of the light colored minerals quartz and feldspar.
These grains were probably eroded from granitic rocks
in the San Bernadino Mountains and transported eastward by the Mojave River.