Mojave Desert - (MAP)
subsection is the alluvial plain of Death Valley, from Sand Spring south-southeast
to the drainage divide between Death Valley and Silurian Valley.
It has a very hot arid climate. MLRAs 30g and 30h.
Lithology and Stratigraphy
This subsection contains mostly
Quaternary alluvial fan, basin-fill, and lacustrine deposits. There
is some dune sand on the east sides of playas. Small areas
of Pliocene nonmarine sedimentary rocks are included in this subsection.
This subsection contains predominantly nearly level lake plain and basin
floor and gently to moderately sloping alluvial fans. There are some
moderately steep slopes on upper fans and Pliocene sedimentary rocks.
Beach ridges and strand-lines mark the edges of former lakes. The
valley is oriented toward the north-northwest. The elevation range
is from -282 feet at Badwater up to about 4000 feet. Fluvial erosion
and deposition and eolian deflation and deposition are the main geomorphic
The soils are mostly Typic Torrifluvents and Typic Torriorthents, but also
Typic Torripsamments, Typic Haplocalcids, Typic Haplargids, and shallow
Typic Haplodurids. Lithic and shallow Typic Torriorthents are common
on Pliocene sedimentary rocks. The lake plains are mostly playas
that have only recently become exposed on the surface and still lack vascular
plant cover. The soils are well drained. The soil temperature
regimes are mostly thermic, but hyperthermic on the basin floor in the
center of Death Valley. Soil moisture regimes are aridic.
The predominant natural plant communities on fans are Desert-holly series
and, higher up the fans, Creosote bush series.
is replaced by Allscale series toward the southern end of the valley.
Brittlebush series and White bursage series are common in washes on the
fans. The predominant natural plant communities on lacustrine deposits
are Iodine bush series and Saltgrass series. Mesquite series and
Arrow weed series are common around the edges of saltmarshes. Much
of the dry lake plain is devoid of vascular plants, because of high salt
content (ground water salt >6%).
Characteristic series by lifeform include:
Climate. The mean annual precipitation is about 3 to 5 inches.
It is all rain. Mean annual temperature is about 60° to
77° F. The mean freeze-free period is about 225 to 325 days.
Grasslands: Desert sand - verbena series, Indian ricegrass
series, Pickleweed series, Saltgrass series.
Shrublands: Allscale series, Brittlebush series, Creosote bush
series, Creosote bush - white bursage series, Desert-holly series, Iodine
bush series, White bursage series.
Forests and woodlands: Mesquite series.
Surface Water. Runoff is rapid from alluvial fans and slow
from basin-fill. Drainage is internal, there is no outlet for surface
water. The Amargosa River, which is the largest stream draining into
Death Valley, is dry most of each year; but it does have several large
springs along its channel. There is temporary ponding on playas,
or dry lake beds.
Mojave Desert -
clickable map - select a section to view
Looking east across Death Valley from
in the Panamint Mountain Range
Death Valley National Park