Elevation
Badwater has the lowest elevation of any point on land in North America (some lake bottoms are deeper, but Badwater is somewhere we can stand without getting wet!).
The elevation is due to pulling apart this region of California: as you stretch the continental crust, it breaks, along faults, and blocks of crust slide down past each other. The northern and southern ends of Death Valley result from this type of motion (the central part of the valley actually results from crustal blocks sliding past each other laterally instead).
Salt
precipitation
The water has a high salt content.
"Salts" are dissolved materials, of which table salt (NaCl, the mineral
halite) is just one type.
Saltcracks:
the early stages
When mud, or salt sheets, contain water, and then dry out, they contract, so as to occupy less space. The basic form of contraction is that the ground contracts to a point in 6 directions, under ideal circumstances forming hexagons. However life is not perfect, and hexagons are rare. The general term for the shapes produced by this drying out-related contraction is "polygon".
Here, at the edge of the Badwater Basin, some salty areas are drying out, and the salt is cracking into polygons.
Mud does this also, as can be seen along lake and river shores in many areas of the world (and even puddles on muddy soils in NJ). We saw mudcracks on the sand dunes near Stovepipe Wells.
Saltcracks:
the later stages
Further out on the salt flats, saltcracks are well developed, and form ridges on the surface. There are two scales of ridges visible in this photo, formed by two different rates of drying out. Unlike "normal" mudcracks, saltcracks form ridges because there is still a little water below the surface, from which more salt is precipitating and growing as crystals; these salt crystals require space, and therefore push up the overlying material. The easiest place to do this is at the saltcracks, so, the saltcracks get pushed up. The brown ridges here are discolored by mud that is present below the salt surface. (Geologically, "mud" refers to any land-derived particle, resulting from weathering and erosion of the land, that is smaller than 1/256th of a millimeter.)
Note the geologist for scale in the middle of the photo.
Saltcracks:
polygons
This photo shows the polygons very nicely.
The sloping surface in the left background is an alluvial fan.
Saltcracks
and alluvial fan
The cone of material at the base of the cliff is an alluvial fan. The different colors (gray, light brown) reflect different ages of material: the gray material has been deposited very recently, and marks the currently-active course of braided streams over the fan's surface, whereas the brown material is where deposition took place further in the past - the brown is desert varnish on these earlier-deposited materials.
Alluvial
fan
Side view of a classic alluvial fan.
The gray horizontal line about a fifth of the way up from the base marks the road, which can also be seen from Dante's View.
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