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Ecological Sections: Mono
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: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.< previous - Mono - next >