Subsection 341Dk
Fort Sage Mountains - Lemmon Valley
This subsection includes mountains, hills, and valleys between the Sierra
Nevada on the west and the Pah Rah Range and Pyramid Lake on the
east. The larger mountains are the Fort Sage Mountains, Virginia
Mountains, Dogskin Mountain, and Petersen Mountain. The larger valleys
are Long Valley, Lemmon Valley, and Warm Springs Valley. The climate
is temperate to cold, and semi-arid. MLRA 26F.
Lithology and Stratigraphy. Tertiary basalt predominates
in the mountains and hills. Also, there are Cenozoic tuff and tuffaceous
sediments and Quaternary basalt. Mesozoic granitic and Pre-Cretaceous
metavolcanic rocks are exposed beneath the volcanic rocks on the western
side of the subsection. The valleys contain Quaternary alluvial and
lacustrine deposits. Tertiary lacustrine deposits are extensive in
Long Valley.
Geomorphology. This subsection contains steep mountains,
moderately steep hills, gently to moderately sloping alluvial fans, and
nearly level floodplains and basin floors. The mountains are aligned
north-south in the southern and eastern parts of the subsection, curving
around to the northwest in the northwestern part. The elevation range
is from about 4000 feet adjacent to Pyramid Lake up to 7990 feet in the
Fort Sage Mountains and 8722 feet on Tule Peak in the Virginia Mountains.
Mass wasting, fluvial erosion and deposition, and freeze-thaw are the main
geomorphic processes.
Soils. The soils on mountains and hills are mostly Lithic,
Aridic, Aridic Calcic, Aridic Pachic, and Pachic Argixerolls; Lithic
Xerollic and Xerollic Haplargids; Entic Ultic Haploxerolls; and shallow
Xerollic Durargids. Those on granitic rocks are mostly shallow Xeric
Torripsamments, Torripsammentic and Entic Haploxerolls, and shallow Aridic
and Ultic Argixerolls. Soils on alluvial fans are mostly Typic Torriorthents,
Aridic Haploxerolls, Pachic Argixerolls, Xerollic Haplargids, and Abruptic
Xerollic Durargids. Those on floodplains and basin floors are
mostly Typic Xerofluvents, Aridic Cumulic Haploxerolls, Typic Haplaquepts,
Typic Haplaquolls, Aquic Argixerolls, and Aquic Natrargids. Also,
there are Chromoxererts on dry lake beds. The soils are well
drained, except for somewhat poorly to poorly drained soils on floodplains
and basin floors. Soil temperature regimes are mesic and frigid.
Soil moisture regimes are mostly aridic at lower elevations and xeric at
higher elevations. Ephemerally to permanently wet soils on floodplains
and basin floors have xeric or aquic moisture regimes.
Vegetation. The predominant natural plant communities
are Big sagebrush series at lower and Utah and Western juniper series at
higher elevations. Shadscale series prevails at low elevations near
Pyramid Lake. Greasewood series, Saltgrass series, and Sedge
meadow alliances occur on somewhat poorly to poorly drained floodplains
and basin floors. Low sagebrush series is common on shallow soils.
Characteristic series by lifeform include:
Grasslands: Alkali sacaton series, Ashy ryegrass series,
Beaked sedge series, Bluebuch wheatgrass series, Cordgrass series, Creeping
ryegrass series, Indian ricegrass series, Needle-and-thread series, Saltgrass
series.
Shrublands: Allscale series, Big sagebrush series, Bitterbrush
series, Bush seepweed series, Fourwing saltbush series, low sagebrush series,
Mixed saltbush series, Rubber rabbitbrush series, Shadscale series, Winter
fat series.
Forests and woodlands: Utah pinyon series, Mountain juniper
series.
Climate. The mean annual precipitation is about 6 to 16 inches.
Much of the precipitation is snow. Mean annual temperature is about
35° to 54° F. The mean freeze-free period is in the range
from 75 to 150 days.
Surface Water. Runoff is rapid from alluvial fans and slow
from basin floors. Some drainages are closed, with ephemeral lakes
in the valleys, but much of the runoff is to Pyramid Lake or to Honey Lake.
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