Sedimentation in Death Valley is controlled by tectonics and aridity. The far side of the valley has no major fault: sediments eroding from the mountain range pile up to create the thick alluvial fans at the toe of the range. The near side of the valley has a major fault that causes the valley floor to sink and the adjacent mountains to rise. The subsiding valley prevents thick alluvial fans from forming on the surface (they are carried downward by the fault before they can build up too high) and it puts the lowest point in the valley right next to the mountains on which the photo was taken (as opposed to in the center of the valley). In fact, the low point in the valley is the low point in the western hemisphere: Badwater (white salt flats in foreground) has an elevation of some 281 feet below sealevel.

The salt flats result from the fact that Death Valley is internally drained: water that flows into the valley cannot flow out. All dissolved solids resulting from rock weathering are eventually carried to this salt flat and left behind when the water evaporates. If the local climate were to become more humid, a lake several hundred feet deep would form until it spilled over a ridge at the south end of the valley.

The salt flats are strikingly beautiful. Note how they run right up to the small alluvial fan on the far right. In the center background is a greenish ridge (not the skyline) that represents the exposed surface of the fault that bounds this side of the valley. To the left, the valley subsides. To the right, the mountains rise. The ridge continues in a smooth arc for some distance up into the mountains and forms a distinctive geomorphic feature called a turtleback.

From a distance, the alluvial fans appear to be made of fine gravel. However, up close some of them are made of considerably coarser material:

The extreme aridity of Death Valley contrasts strongly with the abundant evidence for huge floods. These boulders were carried by an extremely strong current that washed down the narrow valley in the upper center of the photo and flowed out onto this broad fan on the valley floor. When the flow spread out, the current velocities dropped and were no long able to transport these very heavy rocks. Deserts commonly see flash floods that are capable of moving a great deal of sand, gravel, boulders, and campers who set up their tends in a nice flat spot in a temporarily dry drainage.