Overview of the Mojave
Shaping the "Classic American Desert"
Despite its archetypal status, the Mojave does not really fit the classic image of a desert. For example, it contains
only in limited areas, and is characterized by parched mountains that rise abruptly from alternating
plains, or basins. The area of most dramatic relief is around
California, where the elevation drops
from 3,400 m above sea level at Telescope Peak to 88 m below sea level at
surface distance of only 23 km.
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The Mojave's mountains are in fact burying themselves in their own debris as storm-driven rocks and boulders pour
from canyons, spreading out to build gigantic
Where several deposits join, they form
slopes sprinkled with
Bajadas are capped with
composed of gravel and small rocks,
overlaid with delicate
clay and other particles cemented to rock surfaces by
manganese and iron that have been oxidized by bacteria over thousands of years. The large expanses of the
Mojave's bajadas make them the dominant geomorphologic feature of the Mojave Desert
Since basins have no outlets, when rainfall collects and
it leaves behind flat
which almost nothing will grow. The white surfaces of these
are startling against the duller,
brown back-ground. Playas, such as
at the end of the
in California, are among the flattest
landforms in the world. Dry riverbeds, or
are also present in the Mojave, as are
The Mojave Desert is a subsection of the Basin and Range Physiographic Province, which is characterized by long,
north-south-trending mountain ranges separated by broad valleys.
rocks of the Mojave Desert reveal
landscapes as old as 2.7 billion years--over half the age of the Earth.
era the Mojave Desert was covered by shallow seas, as evidenced by
marine creatures in
and dolomite. These fluctuating seas deposited thousands of meters of
that can be seen in
banded mountains throughout the Mojave. Limestone has played an important role in the history of the Mojave as a
host rock for metallic mineral veins, which were produced when magma intruded.
During the Mesozoic era the Mojave region was uplifted. Salt-laden water bodies evaporated, leaving behind puffy
crusts of evaporite minerals, such as halite and gypsum. Rivers and
streams carried large amounts of
materials into the lowlands.
became even more
and windy than it is today, causing the formation of belts of sand dunes
and creating the cross-bedding patterns that are visible in the colorful sandstone of Nevada's
Red Rock Canyon
At the beginning of the
era tectonic activity resumed. Movement along
deformed the Mojave's layers
of sediment and underlying metamorphic rock. Shifts along thrust faults forced older layers on top of younger ones,
as can be seen at Red Rock Canyon National Conservation Area.
Faulting was accompanied by an increase in
activity. At present-day Death Valley, these processes pushed
up mountains and caused the valley floor to drop, forming a below-sea-level trough.
cinder cones and lava flows
are reminders of this active period. About
17.8 million years ago, a powerful volcanic eruption in the Woods Mountains dispersed a low cloud of ash and
rock fragments across the countryside, burying shallow lakes and stands of trees. The fossils of ancient life
forms are preserved in sediments below this ash layer.
The Mojave is a
"accommodation zone" between the surrounding Pacific and North American plates, which causes
the region to experience relatively strong earthquake activity along numerous
For example, a 7.6 magnitude
earthquake in the
shook a wide area in June 1992--the largest quake to strike California in 40 years.
In October 1999, a 7.1 magnitude earthquake jolted
and surrounding areas. Twenty-five aftershocks
of magnitude 4.0 or greater occurred within 36 hours of the main shock.
Mojave Desert Geology
Application of the natural sciences to the physical formations found inside and on the ...
Telescope peak during flooding of
is remniscent of ancient lakes -
Death Valley -
El Mirage dry lake (playa)
Cinder cone field -
Mojave National Preserve -
Craters & Volcanic Features
Kelso sand dunes -
Mojave National Preserve -