La Sal Mountains, Grand and San Juan Counties, Utah
Photographer: Jay Hill
The La Sal Mountains, near Moab in southeastern Utah, are laccoliths formed when upwelling magma intruded into and bulged the overlying sedimentary rock layers upward. The magma did not reach the surface, but subsequent erosion of the softer sedimentary rocks exposed the peak-forming igneous rocks that rise above the surrounding landscape.