Coso - Argus Ranges

This subsection is between the Owens Valley and Panamint Valley.  It includes the Coso and Argus Ranges and hills and valley between the two mountain ranges.  It has a hot to temperate, arid climate.   MLRA 29f.

Lithology and Stratigraphy.  The bedrock is mainly Mesozoic granitic; Paleozoic marine sedimentary; Pre-Cretaceous metamorphic; and Pliocene and Pleistocene  volcanic rocks.  Most of the Paleozoic is represented, at least from Ordovician through Permian.  The volcanic rocks are mostly basalt, but there are also some pyroclastic rocks.  The Quaternary is well represented by alluvium.

Geomorphology.   This subsection contains steep mountains, moderately steep hills, gently to moderately sloping alluvial fans and pediments, and nearly level floodplain and basin floor.  Most of the mountains are aligned north-south, but the Darwin Hills and Santa Rosa Hills are aligned more toward the north-northwest.  There are high plateaus, such as Joshua Flat at the north end of the Coso Range, that appear to be old pediments. Cinder cones are common in areas of Pleistocene volcanism.  The elevation range is from about 2000 feet up to 8160 in the Coso Range  and 8839 feet on Maturango Peak in the Argus Range.  Mass wasting, fluvial erosion and deposition, and freeze-thaw are the main geomorphic processes.

Soils.  The soils on mountains and hills are mostly Lithic Torriorthents, Lithic Camborthids, and Aridic Argixerolls, plus shallow Typic Torriorthents and shallow Aridic Haploxerolls on granitic rocks and Lithic Haplargids on volcanic rocks.  Soils on alluvial fans and basin floors are mostly Typic and Xeric Torrifluvents and Torriorthents, plus Xerollic Haplargids on older alluvial fans.  The soils are well drained.  Soil temperature regimes are thermic and mesic.   Soil moisture regimes are aridic.

Vegetation.   The predominant natural plant communities, from lower to higher elevations are Creosote bush series, Mixed saltbush series, Black bush series, Big sagebrush series, and Singleleaf pinyon series.  Also, Joshua tree series occurs at lower elevations.

Characteristic series by lifeform include:

Grasslands: Indian ricegrass series, Needle-and-thread series.

Shrublands: Big sagebrush series,  Black bush series, Brittlebush series, Creosote bush series, Creosote bush - white bursage series,  Hop-sage series,  Joshua tree series, White bursage series.

Forests and woodlands: Curlleaf mountain-mahogany series, Singleleaf pinyon series, Singleleaf pinyon - Utah juniper series, Utah juniper series.

Surface Water.  Runoff is rapid from alluvial fans and slow from basin floors.  It drains to either Owens Valley or Panamint Valley.  Streams are dry most of each year.