WorldWideScience

Sample records for sierra nevada batholith

  1. Uranium-lead isotopic ages from the Sierra Nevada Batholith, California

    Science.gov (United States)

    Chen, J.

    1982-01-01

    This study provides new information on the timing and distribution of Mesozoic magmatic events in the Sierra Nevada batholithic complex chiefly between 36° and 37°N. latitude. U-Pb ages have been determined for 133 zircon and 7 sphene separates from 82 samples of granitoid rocks. Granitoid rocks in this area range in age from 217 to 80 m.y. Triassic intrusions are restricted to the east side of the batholith; Jurassic plutons occur south of the Triassic plutons east of the Sierra Nevada, as isolated masses within the Cretaceous batholith, and in the western foothills of the range; Cretaceous plutons form a continuous belt along the axis of the batholith and occur as isolated masses east of the Sierra Nevada. No granitic intrusions were emplaced for 37 m.y. east of the Sierra Nevada following the end of Jurassic plutonism. However, following emplacement of the eastern Jurassic granitoids, regional extension produced a fracture system at least 350 km long into which the dominantly mafic, calc-alkalic Independence dike swarm was intruded 148 m.y. ago. The dike fractures probably represents a period of regional crustal extension caused by a redistribution of the regional stress pattern accompanying the Nevadan orogeny. Intrusion of Cretaceous granitic plutons began in large volume about 120 m.y. ago in the western Sierra Nevada and migrated steadily eastward for 40 m.y. at a rate of 2.7 mm/y. This slow and constant migration indicates remarkably uniform conditions of subduction with perhaps downward migration of parent magma generation or a slight flattening of the subduction zone. Such steady conditions could be necessary for the production of large batholithic complexes such as the Sierra Nevada. The abrupt termination of plutonism 80 m.y. ago may have resulted from an increased rate of convergence of the American and eastern Pacific plates and dramatic flattening of the subduction zone. U-Pb ages of the Giant Forest-alaskite sequence in Sequoia National Park are

  2. Thermal evolution and exhumation of deep-level batholithic exposures, southernmost Sierra Nevada, California

    Science.gov (United States)

    Saleeby, J.; Farley, K.A.; Kistler, R.W.; Fleck, R.J.

    2007-01-01

    The Tehachapi complex lies at the southern end of the Sierra Nevada batholith adjacent to the Neogene-Quaternary Garlock fault. The complex is composed principally of high-pressure (8-10 kbar) Cretaceous batholithic rocks, and it represents the deepest exposed levels of a continuous oblique crustal section through the southern Sierra Nevada batholith. Over the southern ???100 km of this section, structural/petrologic continuity and geochronological data indicate that ???35 km of felsic to intermediate-composition crust was generated by copious arc magmatism primarily between 105 and 99 Ma. In the Tehachapi complex, these batholithic rocks intrude and are bounded to the west by similar-composition gneissic-textured high-pressure batholithic rocks emplaced at ca. 115-110 Ma. This lower crustal complex is bounded below by a regional thrust system, which in Late Cretaceous time tectonically eroded the underlying mantle lithosphere, and in series displaced and underplated the Rand Schist subduction assemblage by low-angle slip from the outboard Franciscan trench. Geophysical and mantle xenolith studies indicate that the remnants of this shallow subduction thrust descend northward through the crust and into the mantle, leaving the mantle lithosphere intact beneath the greater Sierra Nevada batholith. This north-dipping regional structure records an inflection in the Farallon plate, which was segmented into a shallow subduc-tion trajectory to the south and a normal steeper trajectory to the north. We combine new and published data from a broad spectrum of thermochronom-eters that together form a coherent data array constraining the thermal evolution of the complex. Integration of these data with published thermobarometric and petro-genetic data also constrains the tectonically driven decompression and exhumation history of the complex. The timing of arc magmatic construction of the complex, as denoted above, is resolved by a large body of U/Pb zircon ages. High

  3. Geochronology and Geochemistry of a Late Cretaceous Granitoid Suite, Santa Rosa Range, Nevada: Linking Arc Magmatism in Northwestern Nevada to the Sierra Nevada Batholith

    Science.gov (United States)

    Brown, K.; Stuck, R.; Hart, W. K.

    2010-12-01

    Throughout the Mesozoic, an arc-trench system dominated the western margin of North America. One of the principal records of this system’s evolution is a discontinuous alignment of deeply eroded batholiths, which represent the once-active roots of ancient volcanic systems. Although these batholiths extend from Alaska to Mexico, there is a prominent (~500 km) gap located in present-day Nevada that contains scattered plutons that are hypothesized to be similar in age and origin to the larger batholiths. The current understanding of these isolated plutons, however, remains limited to regional isotopic studies aimed at identifying major crustal boundaries and structural studies focused on emplacement mechanisms. Therefore, detailed petrogenetic studies of the plutons exposed within the Santa Rosa Range (SRR) of NW Nevada will better characterize magmatism in this region, placing them within a regional context that explores the hypothesized links between the intrusions of NW Nevada to the Sierra Nevada batholith (SNB). A compilation of published geochronology from this region shows that plutons in the SRR are broadly coeval with the Cathedral Range Intrusive Epoch (~95-83 Ma) and the Shaver Sequence (~118-105 Ma) of the SNB. Preliminary Rb-Sr geochronology from the Granite Peak stock reveals a previously unrecognized period of magmatism (ca. 85.0 Ma) in this region. Therefore, ongoing work will more completely characterize the timing of magmatic pulses in this region and their relationships to the SNB. Preliminary petrographic, geochemical, and isotopic observations suggest that two distinct compositional/textural groups exist: the Santa Rosa/ Andorno group (SRA) and Granite Peak/ Sawtooth group (GPS). The chemical and isotopic variations between the two groups suggest that they were not consanguineous. Whereas the SRA group is generally more mafic (64-72 wt% SiO2) and metaluminous, the GPS group is more felsic (72- 76 wt% SiO2) and peraluminous. This observation is

  4. Cracking the Stoping Paradigm: Field and Modeling Constraints From the Sierra Nevada Batholith

    Science.gov (United States)

    Pignotta, G. S.; Paterson, S. R.; Okaya, D.

    2001-12-01

    The significance of stoping during pluton emplacement remains a controversial issue. This mechanism has fallen out of favor recently largely due to the apparent lack of stoped blocks preserved in plutons. Our field studies in plutons in a variety of tectonic settings clearly show evidence of stoping. This is not surprising since stoping should be favored when large thermal gradients exist at magma-host rock boundaries. Preservation of stoped blocks is uncommon however, since the rate at which blocks sink is much greater than the rate at which magmas crystallize (Paterson and Okaya, 1999). Thus, only during final crystallization when magmatic yield strength is high, should stoped blocks be trapped. The Mitchell Peak granodiorite, Sierra Nevada is a rare example of a pluton that preserves abundant stoped blocks, with the youngest intrusive phase preserving >25% stoped blocks, and locally, near the margins >50% of exposed surface area is stoped blocks. Thus stoping is an important process here, at least during the final stages of emplacement. This area is ideal to study the mechanisms of block formation and disintegration using both field and modeling techniques, because of abundant stoped blocks, excellent exposure, and nature of host rock. The host rock is a slightly older, coarse grained, granodioritic intrusion that preserves extremely weak to no magmatic fabric, and thus can be treated as a "homogeneous and isotropic" medium for the purposes of thermal-mechanical modeling. Detailed mapping indicates that preserved stoped blocks range in size from hundreds of m's to xenocrystic feldspars, and there is abundant evidence for mechanical disintegration of blocks. Thermal-mechanical models, using detailed maps from the Mitchell Peak area, further support field observations. Rates at which thermal stresses develop and exceed host rock tensile strength are extremely rapid (hours to days) compared to onset of crystal plastic flow and/or melting. The calculated pattern of

  5. The influence of subsurface porosity and bedrock composition on ecosystem productivity and drought resilience in the Sierra Nevada Batholith, California

    Science.gov (United States)

    Riebe, C. S.; Callahan, R. P.; Goulden, M.; Pasquet, S.; Flinchum, B. A.; Taylor, N. J.; Holbrook, W. S.

    2017-12-01

    The availability of water and nutrients in soil and weathered rock influences the distribution of Earth's terrestrial life and regulates ecosystem vulnerability to land use and climate change. We explored these relationships by combining geochemical and geophysical measurements at three mid-elevation sites in the Sierra Nevada, California. Forest cover correlates strongly with bedrock composition across the sites, implying strong lithologic control on the ecosystem. We evaluated two hypotheses about bedrock-ecosystem connections: 1) that bedrock composition influences vegetation by moderating plant-essential nutrient supply; and 2) that bedrock composition influences the degree of subsurface weathering, which influences vegetation by controlling subsurface water-storage capacity. To quantify subsurface water-holding capacity, we used seismic refraction surveys to infer gradients in P and S-wave velocity structure, which reveal variations in porosity when coupled together in a Hertz-Mindlin rock-physics model. We combined the geophysical data on porosity with bedrock bulk geochemistry measured in previous work to evaluate the influence of water-holding capacity and nutrient supply on ecosystem productivity, which we quantified using remote sensing. Our results show that more than 80% of the variance in ecosystem productivity can be explained by differences in bedrock phosphorus concentration and subsurface porosity, with phosphorus content being the dominant explanatory variable. This suggests that bedrock composition exerts a strong bottom-up control on ecosystem productivity through its influence on nutrient supply and weathering susceptibility, which in turn influences porosity. We show that vegetation vulnerability to drought stress and mortality can be explained in part by variations in subsurface water-holding capacity and rock-derived nutrient supply.

  6. USC Undergraduate Team Research, Geological Field Experience and Outdoor Education in the Tuolumne Batholith and Kings Canyon, High Sierra Nevada

    Science.gov (United States)

    Culbert, K. N.; Anderson, J. L.; Cao, W.; Chang, J.; Ehret, P.; Enriquez, M.; Gross, M. B.; Gelbach, L. B.; Hardy, J.; Paterson, S. R.; Ianno, A.; Iannone, M.; Memeti, V.; Morris, M.; Lodewyk, J.; Davis, J.; Stanley, R.; van Guilder, E.; Whitesides, A. S.; Zhang, T.

    2009-12-01

    Within four years, USC’s College of Letters, Arts and Sciences and Earth Science department have successfully launched the revolutionary undergraduate team research (UTR) program “Geologic Wonders of Yosemite at Two Miles High”. A diverse group of professors, graduate students and undergraduates spent two weeks mapping the Boyden Cave in Kings Canyon National Park, the Iron Mountain pendants south of Yosemite, the Western Metamorphic belt along the Merced River, and the Tuolumne Batholith (TB) in June and August 2009. During their experience in the field, the undergraduates learned geologic field techniques from their peers, professors, and experienced graduate students and developed ideas that will form the basis of the independent and group research projects. Apart from teaching undergraduates about the geology of the TB and Kings Canyon, the two weeks in the field were also rigorous exercise in critical thinking and communication. Every day spent in the field required complete cooperation between mentors and undergraduates in order to successfully gather and interpret the day’s data. Undergraduates were to execute the next day’s schedule and divide mapping duties among themselves. The two-week field experience was also the ideal setting in which to learn about the environmental impacts of their work and the actions of others. The UTR groups quickly adapted to the demanding conditions of the High Sierra—snow, grizzly bears, tourists, and all. For many of the undergraduates, the two weeks spent in the field was their first experience with field geology. The vast differences in geological experience among the undergraduates proved to be advantageous to the ‘team-teaching’ focus of the program: more experienced undergraduates were able to assist less experienced undergraduates while cementing their own previously gained knowledge about geology. Over the rest of the academic year, undergraduates will learn about the research process and scientific

  7. Postorogenic emplacement of the Santa Marta Batholith, northwestern flank of the Sierra Nevada de Santa Marta (SNSM).

    Science.gov (United States)

    Sanchez Sierra, Johan Miguel Sebastian; Kammer, Andreas

    2017-04-01

    The Santa Marta Batholith (BSM) belongs to a Paleogene intrusive suite of the Santa Marta massif, an exhumed triangular block at the southern Caribbean margin. Its Paleogene age precludes its association to an active margin, although its emplacement was controlled by the flexure of the down-bent Southamerican plate. Its internal structure is outlined by a mafic border facies and a felsic core, both having a petrologic affinity to a TTG-suite. According to existing age data, the BSM consolidated sequentially from SW to NE, with a first pulse having crystallized at 56 Ma in the southern domain and a final pulse in the northern domain at 52-50 Ma. Pressures varied between 5-7 kb, corresponding to depths of 14-19 km. This study combines structural, thermochronological and geochemical data with an analysis of Anisotropy and Magnetic Susceptibility (AMS) and paleomagnetism. The SNSM had a clockwise rotation of 30 ° and the ASM results help distinguish between two fault-bounded structural domains. The southern domain is characterized by a magnetic foliation concordant to the contact of the host rock that dips toward the hinterland. The northern domain, in contrast, displays a N-S trending magnetic foliation that is oblique to the regional structural northeastern trend. This divergence is supported by the orientation of mineral lineations, enclaves and dikes. In spite of its arc signature, anomalies like enrichment in Ti, depletion of Nb-Ta and Zr-Hf, as well as flat REE patterns can be associated to the accumulation of crystallized mafic minerals from less-fractionated magmas. These data evidence mingling. Asymmetric internal organization, as indicated by a hinterland-dipping roof pendent, the structural setting at the margin of a thickened continental margin and its geochemical signature favor a scenario of a magma generation at a mid-crustal level and its consequent extrusion along a channel, that connected to the crustal bend of the continental plate that was

  8. Sierra Nevada Subregional Boundary - Sierra Nevada Conservancy [ds542

    Data.gov (United States)

    California Natural Resource Agency — Sierra Nevada Conservancy (SNC) boundary. The boundary was mapped to correspond with statute AB 2600 (2004) and as re-defined in AB 1201 (2005). Work on the boundary...

  9. Quaternary environments in Sierra Nevada

    OpenAIRE

    Oliva, Marc; Gómez Ortiz, Antonio; Palacios Estremera, David; Salvador Franch, Ferran; Salvà Catarineu, Monserrat

    2016-01-01

    El conocimiento relativo a la evolución ambiental cuaternaria en las montañas de la Península Ibérica ha avanzado sustancialmente en las últimas décadas. Particularmente significativos son los progresos realizados en el macizo de Sierra Nevada, en el sur peninsular. En este caso, los investigadores se han servido de registros naturales y fuentes documentales para reconstruir la dinámica ambiental desde la Última Glaciación y posterior deglaciación del macizo hasta su evolución reciente. Los c...

  10. Topographic Evolution of the Sierra Nevada Resolved by Inversion of Low-Temperature Thermochronology

    Science.gov (United States)

    McPhillips, D. F.; Brandon, M. T.

    2011-12-01

    At present, there are two competing ideas for the topographic evolution of the Sierra Nevada Range. One idea is that the Sierra Nevada was formed as a monocline in the Cretaceous, marking the transition from the Great Valley forearc basin to the west, and a high Nevadaplano plateau to the east, similar to the west flank of the modern Altiplano of the Andes. Both the thermochronologic signature of local relief and the stable isotopic evidence of a topographic rain shadow support this hypothesis. However, a suite of geomorphic observations suggests that the Sierra gained a large fraction of its present elevation as recently as the Pliocene. This recent surface uplift could have been driven by convective removal of in the lower part of the lithosphere and/or by changes in dynamic topography associated with deep subduction of the Farallon plate. Here we present the first comprehensive analysis of low-temperature thermochronology in the Sierra Nevada, which provides a definitive solution, which indicates that both ideas are likely correct. Our analysis is distinguished by three new factors: The first is that we allow for separate evolutions for the local relief and the long-wavelength topography. Second, we use Al-in-Hb paleobarometry to constrain the initial depth of emplacement for the Sierra Nevada plutons. Third, our analysis is tied to a sea-level reference by using the paleo-bathymetric record of the Great Valley basin, where it on-laps the Sierra Nevada batholith. According to our analysis, westward tilting of the Sierra accounts for 2 km of uplift since 20 Ma. Topographic relief increased by a factor of 2. These findings suggest that the Sierra Nevada lost elevation through most of the Tertiary but regained much of its initial elevation following the onset of surface uplift in the Miocene.

  11. Cretaceous plutonic rocks in the Donner Lake-Cisco Grove area, northern Sierra Nevada, California

    Science.gov (United States)

    Kulow, Matthew J.; Hanson, Richard E.; Girty, Gary H.; Girty, Melissa S.; Harwood, David S.

    1998-01-01

    The northernmost occurrences of extensive, glaciated exposures of the Sierra Nevada batholith occur in the Donner Lake-Cisco Grove area of the northern Sierra Nevada. The plutonic rocks in this area, which are termed here the Castle Valley plutonic assemblage, crop out over an area of 225 km2 and for the most part are shown as a single undifferentiated mass on previously published geological maps. In the present work, the plutonic assemblage is divided into eight separate intrusive units or lithodemes, two of which each consist of two separate plutons. Compositions are dominantly granodiorite and tonalite, but diorite and granite form small plutons in places. Spectacular examples of comb layering and orbicular texture occur in the diorites. U-Pb zircon ages have been obtained for all but one of the main units and range from ~120 to 114 Ma, indicating that the entire assemblage was emplaced in a narrow time frame in the Early Cretaceous. This is consistent with abundant field evidence that many of the individual phases were intruded penecontemporaneously. The timing of emplacement correlates with onset of major Cretaceous plutonism in the main part of the Sierra Nevada batholith farther south. The emplacement ages also are similar to isotopic ages for gold-quartz mineralization in the Sierran foothills west of the study area, suggesting a direct genetic relationship between the voluminous Early Cretaceous plutonism and hydrothermal gold mineralization.

  12. Groundwater quality in the Sierra Nevada, California

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2014-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project (PBP) of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. The Sierra Nevada Regional study unit constitutes one of the study units being evaluated.

  13. Invasive exotic plant species in Sierra Nevada ecosystems

    Science.gov (United States)

    Carla M. D' Antonio; Eric L. Berlow; Karen L. Haubensak

    2004-01-01

    The Sierra Nevada is a topographically and floristically diverse region of the western United States. While it comprises only a fifth of the total land area of California, half of the native plant species in the state occur within the range. In addition, more than 400 plant species are endemic to the Sierra Nevada and many of these are listed as threatened or have...

  14. Biosphere and atmosphere interactions in Sierra Nevada forests

    Science.gov (United States)

    Allen H. Goldstein

    2004-01-01

    In the Sierra Nevada, studies are being conducted to assess the impacts of both anthropogenic and biogenic hydrocarbon emissions on regional tropospheric ozone and fine aerosol production. Impacts of ozone deposition and management practices on ecosystem health are also being studied. Human-induced changes in regional air quality have consequences for Sierra Nevada...

  15. Micrometeorological Observations in a Sierra Nevada Meadow

    Science.gov (United States)

    Blackburn, D. A.; Oliphant, A. J.

    2016-12-01

    Mountain meadows play important roles on watershed and ecosystem services, including improving water quality, moderating runoff and providing biodiversity hotspots. In the Sierra Nevada, mountain meadows are an integral part of the mountain ecosystem and watersheds that impact more than 20 million people. Grazing, logging and other forms of anthropogenic land use in the Sierra Nevada have degraded the functioning of meadows, by altering the morphology, hydrology and vegetation. Existing meandering stream networks become incised and straightened by increased runoff, which effectively lowers the water table and completely alters the ecosystem from moist meadow sedges, grasses, and herbs to dryland grass and shrubs. Given the large growth cycle in healthy meadows, it is also expected that they sequester a significant amount of carbon and enhance atmospheric humidity through evapotranspiration, but relatively little work has been done on the bio-micrometeorology of meadows. The purpose of this study is to assess the growing season carbon, water and energy budgets of a partly degraded meadow in the northern Sierra Nevada. Loney Meadow, located at nearly 2,000 m in the Tahoe National Forest, has been identified as a degraded meadow and is scheduled to undergo restoration work to raise the water table in 2017. A micrometeorological tower with eddy covariance instruments was deployed at the site for most of the snow-free period from May to October 2016. The measurements include: fluxes of CO2, water vapor, surface radiation and energy budget components; ancillary meteorological and soil data; and an automated camera capturing daily images of the meadow surface. The poster will present diurnal and seasonal CO2 on a daily basis with a very rapid increase at the onset of the growing season.

  16. Magma mixing in granitic rocks of the central Sierra Nevada, California

    Science.gov (United States)

    Reid, John B.; Evans, Owen C.; Fates, Dailey G.

    1983-12-01

    The El Capitan alaskite exposed in the North American Wall, Yosemite National Park, was intruded by two sets of mafic dikes that interacted thermally and chemically with the host alaskite. Comparisons of petrographic and compositional data for these dikes and alaskite with published data for Sierra Nevada plutons lead us to suggest that mafic magmas were important in the generation of the Sierra Nevada batholith. Specifically, we conclude that: (1) intrusion of mafic magmas in the lower crust caused partial melting and generation of alaskite (rhyolitic) magmas; (2) interaction between the mafic and felsic magmas lead to the observed linear variation diagrams for major elements; (3) most mafic inclusions in Sierra Nevada plutons represent chilled pillows of mafic magmas, related by fractional crystallization and granitoid assimilation, that dissolve into their felsic host and contaminate it to intermediate (granodioritic) compositions; (4) vesiculation of hydrous mafic magma upon chilling may allow buoyant mafic inclusions and their disaggregation products to collect beneath a pluton's domed ceiling causing the zoning (mafic margins-to-felsic core) that these plutons exhibit.

  17. Geomagnetic Polarity Epochs: Sierra Nevada II.

    Science.gov (United States)

    Cox, A; Doell, R R; Dalrymple, G B

    1963-10-18

    Ten new determinations on volcanic extrusions in the Sierra Nevada with potassium-argon ages of 3.1 million years or less indicate that the remanent magnetizations fall into two groups, a normal group in which the remanent magnetization is directed downward and to the north, and a reversed group magnetized up and to the south. Thermomagnetic experiments and mineralogic studies fail to provide an explanation of the opposing polarities in terms of mineralogic control, but rather suggest that the remanent magnetization reflects reversals of the main dipole field of the earth. All available radiometric ages are consistent with this field-reversal hypothesis and indicate that the present normal polarity epoch (N1) as well as the previous reversed epoch (R1) are 0.9 to 1.0 million years long, whereas the previous normal epoch (N2) was at least 25 percent longer.

  18. Site fidelity of the declining amphibian Rana sierrae (Sierra Nevada yellow-legged frog)

    Science.gov (United States)

    Kathleen Matthews; Haiganoush Preisler

    2010-01-01

    From 1997 to 2006, we used mark–recapture models to estimate the site fidelity of 1250 Sierra Nevada yellow-legged frogs (Rana sierrae) in Kings Canyon National Park, California, USA, during their three main activity periods of overwintering, breeding, and feeding. To quantify site fidelity, the tendency to return to and reuse previously occupied...

  19. Contaminant studies in the Sierra Nevadas

    Science.gov (United States)

    Sparling, D.W.; Fellers, G.

    2002-01-01

    full text: Several species of anuran amphibians (frogs and toads) are experiencing severe population declines in even seemingly pristine areas of the Sierra Mountains of California. Among the most severely depressed species are the redlegged frog, the foothill and mountain yellow-legged frogs, the Yosemite toad, and the Cascades frog. Several factors, such as habitat fragmentation, introduced predators (especially fish), and disease, have been linked to these declines. But recent evidence from a USGS-led study shows that contaminants are a primary factor. During the past three years, researchers from the USGS Patuxent Wildlife Research Center, the Western Ecology Research Center, the USDA Beltsville Agriculture Research Center, and the Texas A&M University have teamed up to conduct an extensive study on airborne pesticides and their effects on amphibian populations in the Sierra Nevada Mountains. Previous work on environmental chemistry demonstrated that pesticides from the intensely agricultural Central Valley of California are being blown into the more pristine Sierra Nevada Mountains, especially around Sequoia and Yosemite National Parks. Several pesticides, including diazinon, chlorpyrifos, malathion and endosulfan, can be measured in snow, rainfall, and pond waters in these national parks. With the exception of endosulfan, these pesticides affect and even kill both invertebrates and vertebrate species by inhibiting cholinesterase, an enzyme essential to proper nervous system functioning. In the summer of 2001, we published a paper showing that these same pesticides are now found in adults and the tadpoles of Pacific treefrogs. The results of this landmark study showed that more than 50 percent of the tadpoles and adults sampled in Yosemite and Sequoia National Parks had detectable levels of diazinon or chlorpyrifos and that 86 percent of the Pacific treefrogs sampled in the Lake Tahoe region had detectable levels of endosulfan. In contrast, frogs that were

  20. Geologic Map of the Tower Peak Quadrangle, Central Sierra Nevada, California

    Science.gov (United States)

    Wahrhaftig, Clyde

    2000-01-01

    Introduction The Tower Peak quadrangle, which includes northernmost Yosemite National Park, is located astride the glaciated crest of the central Sierra Nevada and covers an exceptionally well-exposed part of the Sierra Nevada batholith. Granitic plutonic rocks of the batholith dominate the geology of the Tower Peak quadrangle, and at least 18 separate pre-Tertiary intrusive events have been identified. Pre-Cretaceous metamorphic rocks crop out in the quadrangle in isolated roof pendants and septa. Tertiary volcanic rocks cover granitic rocks in the northern part of the quadrangle, but are not considered in this brief summary. Potassium-argon (K-Ar) age determinations for plutonic rocks in the quadrangle range from 83 to 96 million years (Ma), including one of 86 Ma for the granodiorite of Lake Harriet (Robinson and Kistler, 1986). However, a rubidium-strontium whole-rock isochron age of 129 Ma has been obtained for the Lake Harriet pluton (Robinson and Kistler, 1986), which field evidence indicates is the oldest plutonic body within the quadrangle. This suggests that some of the K-Ar ages record an episode of resetting during later thermal events and are too young. The evidence indicates that all the plutonic rocks are of Cretaceous age, with the youngest being the Cathedral Peak Granodiorite at about 83 Ma. The pre-Tertiary rocks of the Tower Peak quadrangle fall into two groups: (1) an L-shaped area of older plutonic and metamorphic rocks, 3 to 10 km wide, that extends diagonally both northeast and southeast from near the center of the quadrangle; and (2) a younger group of large, probably composite intrusions that cover large areas in adjacent quadrangles and extend into the Tower Peak quadrangle from the east, north, and southwest.

  1. Nest trees of northern flying squirrels in the Sierra Nevada

    Science.gov (United States)

    Marc D. Meyer; Douglas A. Kelt; Malcolm P. North

    2005-01-01

    We examined the nest-tree preferences of northern flying squirrels (Glaucomys sabrinus) in an old-growth, mixed-conifer and red fir (Abies magnifica) forest of the southern Sierra Nevada of California. We tracked 27 individuals to 122 nest trees during 3 summers. Flying squirrels selected nest trees that were larger in diameter and...

  2. Groundwater quality in the Southern Sierra Nevada, California

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California's drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State's groundwater quality and increases public access to groundwater-quality information. The Tehachapi-Cummings Valley and Kern River Valley basins and surrounding watersheds in the Southern Sierra Nevada constitute one of the study units being evaluated.

  3. Groundwater quality in the Central Sierra Nevada, California

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California's drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State's groundwater quality and increases public access to groundwater-quality information. Two small watersheds of the Fresno and San Joaquin Rivers in the Central Sierra Nevada constitute one of the study units being evaluated.

  4. Increasing elevation of fire in the Sierra Nevada and implications for forest change

    Science.gov (United States)

    Mark W. Schwartz; Nathalie Butt; Christopher R. Dolanc; Andrew Holguin; Max A. Moritz; Malcolm P. North; Hugh D. Safford; Nathan L. Stephenson; James H. Thorne; Phillip J. van Mantgem

    2015-01-01

    Fire in high-elevation forest ecosystems can have severe impacts on forest structure, function and biodiversity. Using a 105-year data set, we found increasing elevation extent of fires in the Sierra Nevada, and pose five hypotheses to explain this pattern. Beyond the recognized pattern of increasing fire frequency in the Sierra Nevada since the late 20th century, we...

  5. Nitrogen dynamics of spring-fed wetland ecosystems of the Sierra Nevada foothills oak woodland

    Science.gov (United States)

    Randall D. Jackson; Barbara Allen-Diaz

    2002-01-01

    Spring-fed wetlands are small, highly productive, patchy ecosystems nested within the oak woodland/annual grassland matrix of the Sierra Nevada foothills. In an effort to place these wetlands in a landscape context, we described seasonal variation (1999-2000 growing season) in nitrogen cycling parameters at 6 spring-fed wetland sites of the Sierra Nevada foothill oak...

  6. Interaction of an Introduced Predator with Future Effects of Climate Change in the Recruitment Dynamics of the Imperiled Sierra Nevada Yellow-legged Frog (Rana sierrae)

    Science.gov (United States)

    I Lacan; Kathleen R. Matthews; K.V. Feldman

    2008-01-01

    Between-year variation in snowpack (from 20 to 200% of average) and summer rainfall cause large fluctuations in volume of small lakes in the higher elevation (> 3000 m) Sierra Nevada, which are important habitat for the imperiled Sierra Nevada Yellow-legged Frog, Rana sierrae. Climate change (global warming) is predicted to increase these...

  7. Environmental exposures to agrochemicals in the Sierra Nevada mountain range

    Science.gov (United States)

    LeNoir, J.; Aston, L.; Data, S.; Fellers, G.; McConnell, L.; Sieber, J.

    2000-01-01

    The release of pesticides into the environment may impact human and environmental health. Despite the need for environmental exposure data, few studies quantify exposures in urban areas and even fewer determine exposures to wildlife in remote areas. Although it is expected that concentrations in remote regions will be low, recent studies suggest that even low concentrations may have deleterious effects on wildlife. Many pesticides are known to interfere with the endocrine systems of humans and wildlife, adversely affecting growth, development, and behavior. This chapter reviews the fate and transport of pesticides applied in the Central Valley of California and quantifies their subsequent deposition into the relatively pristine Sierra Nevada Mountain Range.

  8. Contrasting magmatic structures between small plutons and batholiths emplaced at shallow crustal level (Sierras de Córdoba, Argentina)

    Science.gov (United States)

    Pinotti, Lucio P.; D'Eramo, Fernando J.; Weinberg, Roberto F.; Demartis, Manuel; Tubía, José María; Coniglio, Jorge E.; Radice, Stefania; Maffini, M. Natalia; Aragón, Eugenio

    2016-11-01

    Processes like injection, magma flow and differentiation and influence of the regional strain field are here described and contrasted to shed light on their role in the formation of small plutons and large batholiths their magmatic structures. The final geometric and compositional arrangement of magma bodies are a complex record of their construction and internal flow history. Magma injection, flow and differentiation, as well as regional stresses, all control the internal nature of magma bodies. Large magma bodies emplaced at shallow crustal levels result from the intrusion of multiple magma batches that interact in a variety of ways, depending on internal and external dynamics, and where the early magmatic, growth-related structures are commonly overprinted by subsequent history. In contrast, small plutons emplaced in the brittle-ductile transition more likely preserve growth-related structures, having a relatively simple cooling history and limited internal magma flow. Outcrop-scale magmatic structures in both cases record a rich set of complementary information that can help elucidate their evolution. Large and small granitic bodies of the Sierra Pampeanas preserve excellent exposures of magmatic structures that formed as magmas stepped through different rheological states during pluton growth and solidification. These structures reveal not only the flow pattern inside magma chambers, but also the rheological evolution of magmas in response to temperature evolution.

  9. GPS Imaging of vertical land motion in California and Nevada: Implications for Sierra Nevada uplift

    Science.gov (United States)

    Blewitt, Geoffrey; Kreemer, Corné

    2016-01-01

    Abstract We introduce Global Positioning System (GPS) Imaging, a new technique for robust estimation of the vertical velocity field of the Earth's surface, and apply it to the Sierra Nevada Mountain range in the western United States. Starting with vertical position time series from Global Positioning System (GPS) stations, we first estimate vertical velocities using the MIDAS robust trend estimator, which is insensitive to undocumented steps, outliers, seasonality, and heteroscedasticity. Using the Delaunay triangulation of station locations, we then apply a weighted median spatial filter to remove velocity outliers and enhance signals common to multiple stations. Finally, we interpolate the data using weighted median estimation on a grid. The resulting velocity field is temporally and spatially robust and edges in the field remain sharp. Results from data spanning 5–20 years show that the Sierra Nevada is the most rapid and extensive uplift feature in the western United States, rising up to 2 mm/yr along most of the range. The uplift is juxtaposed against domains of subsidence attributable to groundwater withdrawal in California's Central Valley. The uplift boundary is consistently stationary, although uplift is faster over the 2011–2016 period of drought. Uplift patterns are consistent with groundwater extraction and concomitant elastic bedrock uplift, plus slower background tectonic uplift. A discontinuity in the velocity field across the southeastern edge of the Sierra Nevada reveals a contrast in lithospheric strength, suggesting a relationship between late Cenozoic uplift of the southern Sierra Nevada and evolution of the southern Walker Lane. PMID:27917328

  10. A Method for Snow Reanalysis: The Sierra Nevada (USA) Example

    Science.gov (United States)

    Girotto, Manuela; Margulis, Steven; Cortes, Gonzalo; Durand, Michael

    2017-01-01

    This work presents a state-of-the art methodology for constructing snow water equivalent (SWE) reanalysis. The method is comprised of two main components: (1) a coupled land surface model and snow depletion curve model, which is used to generate an ensemble of predictions of SWE and snow cover area for a given set of (uncertain) inputs, and (2) a reanalysis step, which updates estimation variables to be consistent with the satellite observed depletion of the fractional snow cover time series. This method was applied over the Sierra Nevada (USA) based on the assimilation of remotely sensed fractional snow covered area data from the Landsat 5-8 record (1985-2016). The verified dataset (based on a comparison with over 9000 station years of in situ data) exhibited mean and root-mean-square errors less than 3 and 13 cm, respectively, and correlation greater than 0.95 compared with in situ SWE observations. The method (fully Bayesian), resolution (daily, 90-meter), temporal extent (31 years), and accuracy provide a unique dataset for investigating snow processes. This presentation illustrates how the reanalysis dataset was used to provide a basic accounting of the stored snowpack water in the Sierra Nevada over the last 31 years and ultimately improve real-time streamflow predictions.

  11. Magnetic susceptibility and relation to initial 87Sr/86Sr for granitoids of the central Sierra Nevada, California

    Science.gov (United States)

    Bateman, P.C.; Dodge, F.C.W.; Kistler, R.W.

    1991-01-01

    Measurement of the magnetic susceptibility of more than 6000 samples of granitic rock from the Mariposa 1?? by 2?? quadrangle, which crosses the central part of the Sierra Nevada batholith between 37?? and 38??N latitude, shows that magnetic susceptibility values are above 10-2 SI units in the east and central parts of the batholith and drop abruptly to less than 10-3 SI units in the western foothills. In a narrow transitional zone, intermediate values (10-3 to 10-2) prevail. Magnetic susceptibility appears to decrease slightly westward within the zones of both high and low values. Magnetic susceptibility in plutonic rocks is chiefly a function of the abundance of magnetite, which depends, in turn, on the total iron content of the rocks and their oxidation ratio. Correlations of magnetic susceptibility with initial 87Sr/86Sr suggest that oxidation ratios have been inherited from the source regions for the magmas from which the rocks crystallized. Reduction of Fe3+ to Fe2+ by organic carbon or other reducing substances may also have affected magnetic susceptibility. -from Authors

  12. Rock-Ice Feature Inventory for the Sierra Nevada, California, USA, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Sierra Nevada is a tectonic uplift mountain range with a gradual gain in elevation on the west side and a steep escarpment on the east. Most of the mapped...

  13. Magnetic Fabric and Paleomagnetism of the Peninsular Ranges Batholith, Sierra San Pedro M rtir, Baja California.

    Science.gov (United States)

    Knight, M.; Herrero-Bervera, E.; Molina-Garza, R. S.; Böhnel, H. N.

    2003-12-01

    We summarize results of recent paleomagnetic, structural, petrologic and magnetic fabric studies along an east-west (60 km long) transect across the Peninsular Ranges Batholith (PRB) in north-central Baja California. The transect includes both magnetite rich plutons from the western sector of the PRB, and ilmenite rich plutons from the eastern sector, as well as plutons on the eastern and western side of major tectonic discontinuities. We include results for 8 plutons, included well-characterized bodies such as San Pedro M rtir (SP), San José (SJ) and La Zarza (LZ), and relatively little known plutons such as Potrero (PO), Aguaje del Burro (AB), El Milagro (MI), and San Telmo (ST). Plutons on the western sector of the PRB yield a paleomagnetic pole at 82° N-186.4° E (A95=4.8° ). When rotated into a pre- Gulf of California position, the pole (79.2° -188.2° ) is statistically undistinguishable from the North American reference pole. In contrast, SP, SJ and PO plutons, on either side of the NW trending Main Martir Thrust yield clearly discordant direction that can only be reconciled with results for the western plutons assuming southwestward tilt of ˜ 25° for SP and greater than 45° for SJ and PO. We find strong evidence in support of tilt of the plutons from thermochronological, structural, and geobarometric data. These data will be discussed elsewhere. Here we focus on magnetic fabric data. AMS for SJ is strongly developed with high values for degree of anisotropy (P= 1.14 a 1.40), but marked east-west asymmetry that contrasts with the general symmetry of the pluton along a north-south axis. Oblate fabrics (T ˜ +0.4) with dispersed lineation directions dominate the west side of the pluton and prolate fabrics (T ˜ -0.15) with steep to vertical lineations dominate on its eastern side. This fabric is interpreted to result from magma flow. SP, a much larger pluton and sensibly asymmetric, displays high degrees of anisotropy (P ˜1.2) on its western side but

  14. Los recursos humanos en un espacio natural protegido: Sierra Nevada

    Directory of Open Access Journals (Sweden)

    Ma. Enriqueta Cózar

    2000-01-01

    Full Text Available Sierra Nevada, como todas las áreas de montaña españolas y gran parte del territorio interior andaluz, ha experimentado durante el siglo XX un considerable retroceso demográfico. La población con la que llega al umbral del siglo XXI es una cuarta parte más pequeña que la registrada en 1900 y un tercio inferior a la de 1950. Diversos y complejos factores, tanto internos como externos al área de montaña, de carácter más económico que demográfico, fueron los desencadenantes de una fuerte emigración. La gran pérdida de población ha originado cambios trascendentales en la demografía y en la actividad económica de Sierra Nevada. En la actualidad, la población de este espacio protegido se caracteriza por una desequilibrada distribución en el territorio, un escaso crecimiento natural, un acelerado envejecimiento y una actividad mayoritariamente terciaria. La declaración, en Julio de 1989, como espacio natural protegido bajo la figura de Parque Natural, y la más reciente de Parque Nacional, apenas ha modificado la inercia demográfica regresiva de la mayor parte de sus municipios; tan sólo se ha podido apreciar una cierta tendencia a la estabilización demográfica de la población total del macizo

  15. Physiochemical characterization of insoluble residues in California Sierra Nevada snow

    Science.gov (United States)

    Creamean, Jessie; Axson, Jessica; Bondy, Amy; Craig, Rebecca; May, Nathaniel; Shen, Hongru; Weber, Michael; Warner, Katy; Pratt, Kerri; Ault, Andrew

    2015-04-01

    The effects atmospheric aerosols have on cloud particle formation are dependent on both the aerosol physical and chemical characteristics. For instance, larger, irregular-shaped mineral dusts efficiently form cloud ice crystals, enhancing precipitation, whereas small, spherical pollution aerosols have the potential to form small cloud droplets that delay the autoconversion of cloudwater to precipitation. Thus, it is important to understand the physiochemical properties and sources of aerosols that influence cloud and precipitation formation. We present an in-depth analysis of the size, chemistry, and sources of soluble and insoluble residues found in snow collected at three locations in the California Sierra Nevada Mountains during the 2012/2013 winter season. For all sites, February snow samples contained high concentrations of regional pollutants such as ammonium nitrate and biomass burning species, while March snow samples were influenced by mineral dust. The snow at the lower elevation sites in closer proximity to the Central Valley of California were heavily influenced by agricultural and industrial emissions, whereas the highest elevation site was exposed to a mixture of Central Valley pollutants in addition to long-range transported dust from Asia and Africa. Further, air masses likely containing transported dust typically traveled over cloud top heights at the low elevation sites, but were incorporated into the cold (-28°C, on average) cloud tops more often at the highest elevation site, particularly in March, which we hypothesize led to enhanced ice crystal formation and thus the observation of dust in the snow collected at the ground. Overall, understanding the spatial and temporal dependence of aerosol sources is important for remote mountainous regions such as the Sierra Nevada where snowpack provides a steady, vital supply of water.

  16. Southern Sierra Nevada Continental Dynamics Project: 1993 field observations of the NPE

    Energy Technology Data Exchange (ETDEWEB)

    Keller, G.R. [Univ. of Texas, El Paso, TX (United States); Malin, P.E. [Duke Univ., Durham, NC (United States); Ruppert, S.D. [LLNL, Livermore, CA (United States)

    1994-12-31

    The Southern Sierra Nevada Continental Dynamics Project is a multidisciplinary, multi-institutional investigation of the cause of the uplift of the Sierra Nevada and its relationship to extension in the adjacent Basin and Range. A broad range of geologic and geophysical data have been collected as part of this project. These data include both passive and active seismic measurements, as well as gravity and magnetotelluric observations. Three seismic refraction/wide-angle reflection profiles were recorded: (1) a 325-km-long, north-south profile extending from just east of Mono Lake south across the Garlock fault, (2) a 400-km-long, east-west profile extending from Death Valley west across the Sierra Nevada to near the San Andreas fault, and (3) a 480-km-long, east-west profile deployed for the NPE. This profile extended from Beatty, Nevada, west across the Sierra Nevada along the previously recorded east-west profile and continued nearly to the Pacific Ocean. Up to 675 seismic recorders were deployed for each profile. These data are allowing us to develop refined models of the crustal and upper mantle structure of the southern Sierra Nevada and to evaluate alternative hypotheses for its uplift and for Basin and Range extension. They also provide insight into the propagation of regional phases across complex structures.

  17. Monitoring lichens diversity and climatic change in Sierra Nevada (Spain

    Directory of Open Access Journals (Sweden)

    Fernández Calzado, M.ª R.

    2013-12-01

    Full Text Available Lichens are common organisms in high mountain zones, where they play an important role in ecosystem balance. In recent years, the increasing interest in understanding more about their interactions with abiotic factors has prompted several investigations, some of which have proved their value as bioindicators of climatic conditions. In this context, focusing on climatic change effects on high mountain vascular plants and supported by the Global Observation Research Initiative in Alpine Environments project (GLORIA, we have monitored for the first time the lichens biodiversity in Sierra Nevada with the intention of studying the alterations caused by the process of climatic change. The aim of this paper is to explain the monitoring experience developed on the massif and contribute to the first results from the biodiversity and statistical analysis of the sampling data.Los líquenes son organismos comunes en las zonas de alta montaña donde juegan un importante papel en el equilibrio de los ecosistemas. En los últimos años, el creciente interés por entender más acerca de sus interacciones con los factores abióticos ha motivado diversas investigaciones, algunas de las cuales han demostrado su valor como bioindicadores de las condiciones climáticas. En este contexto, centrándonos en los efectos del cambio climático en plantas vasculares de alta montaña y respaldados por el proyecto “Iniciativa para la investigación y el seguimiento global de los ambientes alpinos (GLORIA”, se ha monitorizado por primera vez la diversidad de líquenes en Sierra Nevada con la intención de estudiar las posibles alteraciones que esta pueda sufrir causadas por el proceso de cambio climático. El objetivo de este artículo es el de dar a conocer la experiencia de seguimiento en el macizo y aportar los primeros resultados procedentes del análisis, tanto de la biodiversidad como estadístico, de los datos de muestreo.

  18. The saltiest springs in the Sierra Nevada, California

    Science.gov (United States)

    Moore, James G.; Diggles, Michael F.; Evans, William C.; Klemic, Karin

    2017-07-20

    The five saltiest springs in the Sierra Nevada in California are found between 38.5° and 38.8° N. latitude, on the South Fork American River; on Caples Creek, a tributary of the Silver Fork American River; and on the North Fork Mokelumne River. The springs issue from Cretaceous granitic rocks in the bottoms of these major canyons, between 1,200- and 2,200-m elevation. All of these springs were well known to Native Americans, who excavated meter-sized basins in the granitic rock, within which they produced salt by evaporation near at least four of the five spring sites. The spring waters are dominated by Cl, Na, and Ca; are enriched relative to seawater in Ca, Li, and As; and are depleted in SO4, Mg, and K. Tritium analyses indicate that the spring waters have had little interaction with rainfall since about 1954. The waters are apparently an old groundwater of meteoric origin that resided at depth before moving up along fractures to the surface of the exhumed granitic rocks. However, along the way these waters incorporated salts from depth, the origin of which could have been either from marine sedimentary rocks intruded by the granitic magmas or from fluid inclusions in the granitic rocks. Prolonged storage at depth fostered water-rock interactions that undoubtedly modified the fluid compositions.

  19. Dataset of Passerine bird communities in a Mediterranean high mountain (Sierra Nevada, Spain)

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Barea-Azcón, José Miguel; Álvarez-Ruiz, Lola; Bonet-García, Francisco Javier; Zamora, Regino

    2016-01-01

    Abstract In this data paper, a dataset of passerine bird communities is described in Sierra Nevada, a Mediterranean high mountain located in southern Spain. The dataset includes occurrence data from bird surveys conducted in four representative ecosystem types of Sierra Nevada from 2008 to 2015. For each visit, bird species numbers as well as distance to the transect line were recorded. A total of 27847 occurrence records were compiled with accompanying measurements on distance to the transect and animal counts. All records are of species in the order Passeriformes. Records of 16 different families and 44 genera were collected. Some of the taxa in the dataset are included in the European Red List. This dataset belongs to the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area. PMID:26865820

  20. Dataset of Passerine bird communities in a Mediterranean high mountain (Sierra Nevada, Spain).

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Barea-Azcón, José Miguel; Álvarez-Ruiz, Lola; Bonet-García, Francisco Javier; Zamora, Regino

    2016-01-01

    In this data paper, a dataset of passerine bird communities is described in Sierra Nevada, a Mediterranean high mountain located in southern Spain. The dataset includes occurrence data from bird surveys conducted in four representative ecosystem types of Sierra Nevada from 2008 to 2015. For each visit, bird species numbers as well as distance to the transect line were recorded. A total of 27847 occurrence records were compiled with accompanying measurements on distance to the transect and animal counts. All records are of species in the order Passeriformes. Records of 16 different families and 44 genera were collected. Some of the taxa in the dataset are included in the European Red List. This dataset belongs to the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area.

  1. Petrology and geochronology of metamorphosed volcanic rocks and a middle Cretaceous volcanic neck in the east-central Sierra Nevada, California.

    Science.gov (United States)

    Kistler, R.W.; Swanson, S.E.

    1981-01-01

    Metamorphosed Mesozoic volcanic rocks from the E-central Sierra Nevada range in composition from basalt to rhyolite and have ages, based on whole rock Rb-Sr and U-Pb zircon dating, of about 237- 224, 185, 163, 134, and 100Ma. The major plutons of the batholith in this area are of Triassic (215-200Ma) and Cretaceous (94-80Ma) ages. Initial 87Sr/86Sr values for the metamorphosed volcanic rocks of the area are in the range from 0.7042 to 0.7058 and are generally different from the values for the surrounding batholithic rocks (0.7056-0.7066). A circular, zoned granitic pluton, with an outcrop area of 2.5km2, similar in appearance to a ring dike complex, was apparently a conduit for some or possibly all of the middle-Cretaceous metamorphosed volcanic rocks exposed about 5km to the S in the western part of the Ritter Range. Samples from the metamorphosed volcanic rocks and the pluton yield a Rb/Sr whole rock isochron age of 99.9+ or -2.2Ma with an intitial 87Sr/86Sr of 0.7048+ or -0.00001. Major element variation diagrams of the pluton and volcanic rocks define coincident compositional trends. The ages of volcanic events relative to the ages of the major intrusive epochs and the major element and isotopic compositions of the volcanic rocks relative to the major plutons indicate that the volcanic rocks are not simply or directly related to the major plutons in the Sierra Nevada. -from Authors

  2. Soil fauna in forest and coffee plantations from the Sierra Nevada de Santa Mar ta, Colombia

    International Nuclear Information System (INIS)

    Camero R, Edgar

    2002-01-01

    Two research stations (M inca, 700 m altitude and Maria Ter esa, 790 m altitude) were established in the Sierra Nevada de Santa Mar ta in places to study the soil fauna associated with forest and coffee plantations. Soil fauna was collected using pitfall and Bailer's traps. Samples were taken from litter as well as from horizons 0, A and B. individuals collected were identified to family level. Diversity, abundance and frequency indexes were used to compare fauna composition at both sites. Significant differences were found between the two research sites as well as with data from other high altitude forest in the Sierra Nevada de Santa Mar ta

  3. Vulnerability of birds to climate change in California's Sierra Nevada

    Directory of Open Access Journals (Sweden)

    Rodney B. Siegel

    2014-06-01

    Full Text Available In a rapidly changing climate, effective bird conservation requires not only reliable information about the current vulnerability of species of conservation concern, but also credible projections of their future vulnerability. Such projections may enable managers to preempt or reduce emerging climate-related threats through appropriate habitat management. We used NatureServe's Climate Change Vulnerability Index (CCVI to predict vulnerability to climate change of 168 bird species that breed in the Sierra Nevada mountains of California, USA. The CCVI assesses species-specific exposure and sensitivity to climate change within a defined geographic area, through the integration of (a species' range maps, (b information about species' natural history traits and ecological relationships, (c historic and current climate data, and (d spatially explicit climate change projections. We conducted the assessment under two different downscaled climate models with divergent projections about future precipitation through the middle of the 21st century. Assessments differed relatively little under the two climate models. Of five CCVI vulnerability ranking categories, only one species, White-tailed Ptarmigan (Lagopus leucura, received the most vulnerable rank, Extremely Vulnerable. No species received the second-highest vulnerability ranking, Highly Vulnerable. Sixteen species scored as Moderately Vulnerable using one or both climate models: Common Merganser (Mergus merganser, Osprey (Pandion haliaetus, Bald Eagle (Haliaeetus leucocephalus, Northern Goshawk (Accipiter gentilis, Peregrine Falcon (Falco peregrinus, Prairie Falcon (Falco mexicanus, Spotted Sandpiper (Actitis macularius, Great Gray Owl (Strix nebulosa, Black Swift (Cypseloides niger, Clark's Nutcracker (Nucifraga columbiana, American Dipper (Cinclus mexicanus, Swainson's Thrush (Catharus ustulatus, American Pipit (Anthus rubescens, Gray-crowned Rosy-Finch (Leucosticte tephrocotis, Pine Grosbeak

  4. Influence of anuran prey on the condition and distribution of Rana muscosa in the Sierra Nevada

    Science.gov (United States)

    K.L. Pope; K.R. Matthews

    2002-01-01

    Mountain yellow-legged frogs (Rana muscosa) at high elevations of the Sierra Nevada must obtain enough food during summer to survive 7–9 winter months when their aquatic habitats are frozen and food is presumably unavailable. Adults of R. muscosa prey on a variety of organisms, including aquatic and terrestrial invertebrates and...

  5. Aspen in the Sierra Nevada: Regional conservation of a continental species

    Science.gov (United States)

    Paul C. Rogers; Wayne D. Shepperd; Dale L. Bartos

    2007-01-01

    Quaking aspen (Populus tremuloides Michx.) a common species in North America, is a minor species in the Sierra Nevada of California. However, the limited coverage of aspen in this area appears to carry a disproportionate biodiversity load: numerous species are dependent on the unique components of aspen forests habitat. Land managers in the region...

  6. Fire weather and large fire potential in the northern Sierra Nevada

    Science.gov (United States)

    Brandon M. Collins

    2014-01-01

    Fuels, weather, and topography all contribute to observed fire behavior. Of these, weather is not only the most dynamic factor, it is the most likely to be directly influenced by climate change. In this study 40 years of daily fire weather observations from five weather stations across the northern Sierra Nevada were analyzed to investigate potential changes or trends...

  7. Role of oaks in fisher habitat quality in the Sierra Nevada mountains at multiple spatial scales

    Science.gov (United States)

    Craig M. Thompson; Kathryn Purcell; Rebecca Green; Richard. Sweitzer

    2015-01-01

    Fishers (Pekania pennanti) occur in ponderosa pine, mixed conifer, and mixed hardwood conifer habitats in the southern Sierra Nevada at elevations from approximately 1400 to 2300 m. They are a candidate species for listing under both the Federal and California Endangered Species Acts. Since 2007, the U.S. Department of Agriculture, Forest Service (...

  8. Survival of fishers in the southern Sierra Nevada region of California

    Science.gov (United States)

    Richard A. Sweitzer; Craig M. Thompson; Rebecca E. Green; Reginald H. Barrett; Kathryn L. Purcell

    2015-01-01

    Fishers in the western United States were recently proposed for listing under the U.S. Endangered Species Act because of concerns for loss of suitable habitat and evidence of a diversity of mortality risks that reduce survival. One of 2 remnant populations of fishers in California is in the southern Sierra Nevada region, where we studied them at 2 research sites in the...

  9. Ethnobotany of the Sierra Nevada del Cocuy-Güicán

    NARCIS (Netherlands)

    Rodríguez, Mireia Alcántara; Angueyra, Andrea; Cleef, Antoine M.; Andel, van Tinde

    2018-01-01

    Background: The Sierra Nevada del Cocuy-Güicán in the Colombian Andes is protected as a National Natural Park since 1977 because of its fragile páramo ecosystems, extraordinary biodiversity, high plant endemism, and function as water reservoir. The vegetation on this mountain is threatened by

  10. Snowmelt runoff and water yield along elevation and temperature gradients in California's southern Sierra Nevada

    Science.gov (United States)

    Carolyn T. Hunsaker; Thomas W. Whitaker; Roger C. Bales

    2012-01-01

    Differences in hydrologic response across the rain-snow transition in the southern Sierra Nevada were studied in eight headwater catchments – the Kings River Experimental Watersheds – using continuous precipitation, snowpack, and streamflow measurements. The annual runoff ratio (discharge divided by precipitation) increased about 0.1 per 300 m of mean catchment...

  11. Evaluating avian-habitat relationships models in mixed-conifer forests of the Sierra Nevada

    Science.gov (United States)

    Kathryn L. Purcell; Sallie J. Hejl; Terry A. Larson

    1992-01-01

    Using data from two studies in the southern and central Sierra Nevada, we compared the presence and abundance of bird species breeding in mixedconifer forests during 1978-79 and 1983-85 to predictions &om the California Wildlife Habitat Relationships (WHR) System. Twelve percent of the species observed in either study were not predicted by the WHR database to occur...

  12. Silviculture-ecology of forest-zone hardwoods in the Sierra Nevada

    Science.gov (United States)

    Philip M. McDonald; John C. Tappeiner

    1996-01-01

    Although the principal hardwood species in the forest zone of the Sierra Nevada (California black oak, tanoak, Pacific madrone, and canyon live oak) are key components of many ecosystems, they have received comparatively little study. Currently they are underutilized and unmanaged. This paper brings together what is known on the silviculture-ecology of these species...

  13. Carbon and nutrient contents in soils from the Kings River Experimental Watersheds, Sierra Nevada Mountains, California

    Science.gov (United States)

    D.W. Johnson; C.T. Hunsaker; D.W. Glass; B.M. Rau; B.A. Roath

    2011-01-01

    Soil C and nutrient contents were estimated for eight watersheds in two sites (one high elevation, Bull, and one low elevation, Providence) in the Kings River Experimental Watersheds in the western Sierra Nevada Mountains of California. Eighty-seven quantitative pits were dug to measure soil bulk density and total rock content, while three replicate surface samples...

  14. Sierra Nevada grasslands: interactions between livestock grazing and ecosystem structure and function

    Science.gov (United States)

    Barbara H. Allen-Diaz

    2004-01-01

    Livestock grazing plays an integral role in the grass-dominated ecosystems of the Sierra Nevada. Grazing has been asserted to influence such key ecological characteristics as water quality, net primary productivity, nutrient cycling, plant and animal diversity, wildlife habitat availability, and oak regeneration (Belsky and others 1999, Kauffmann and Krueger 1984)....

  15. Using epiphytic macrolichen communities for biomonitoring ammonia in forests of the greater Sierra Nevada, California

    Science.gov (United States)

    Sarah Jovan; Bruce. Mccune

    2006-01-01

    Chronic, excessive nitrogen deposition is potentially an important ecological threat to forests of the greater Sierra Nevada in California. We developed a model for ammonia bioindication, a major nitrogen pollutant in the region, using epiphytic macrolichens. We used non-metric multidimensional scaling to extract gradients in lichen community composition from surveys...

  16. PARTITIONING OF WATER FLUX IN A SIERRA NEVADA PONDEROSA PINE PLANTATION. (R826601)

    Science.gov (United States)

    The weather patterns of the west side of the Sierra Nevada Mountains (cold, wet winters and hot, dry summers) strongly influence how water is partitioned between transpiration and evaporation and result in a specific strategy of water use by ponderosa pine trees (Pinus pond...

  17. West nile virus anti-body surveillance in three Sierra Nevada raptors of conservation concern

    Science.gov (United States)

    J.M. Hull; J.J. Keane; L.A. Tell; H.B. Ernest

    2010-01-01

    West Nile virus (WNV) infection has caused high levels of mortality in North American hawks and owls. To investigate the extent of infection among raptors of conservation concern in the Sierra Nevada, we tested 62 Northern Goshawks (Accipiter gentilis), 209 Spotted Owls (Strix occidentalis), and 22 Great Gray Owls (...

  18. Burn Severity and Its Impact on Soil Properties: 2016 Erskine Fire in the Southern Sierra Nevada

    Science.gov (United States)

    Haake, S.; Guo, J.; Krugh, W. C.

    2017-12-01

    Wildfire frequency in the southern Sierra Nevada has increased over the past decades. The effects of wildfires on soils can increase the frequency of slope failure and debris flow events, which pose a greater risk to people, as human populations expand into foothill and mountainous communities of the Sierra Nevada. Alterations in the physical properties of burned soils are one such effect that can catalyze slope failure and debris flow events. Moreover, the degree of a soil's physical alteration resulting from wildfire is linked to fire intensity. The 2016 Erskine fire occurred in the southern Sierra Nevada, burning 48,019 acres, resulting in soils of unburned, low, moderate, and high burn severities. In this study, the physical properties of soils with varying degrees of burn severity are explored within the 2016 Erskine fire perimeter. The results constrain the effects of burn severity on soil's physical properties. Unburned, low, moderate, and high burn severity soil samples were collected within the Erskine fire perimeter. Alterations in soils' physical properties resulting from burn severity are explored using X-ray diffractometry analysis, liquid limit, plastic limit, and shear strength tests. Preliminary results from this study will be used to assess debris flow and slope failure hazard models within burned areas of the Kern River watershed in the southern Sierra Nevada.

  19. From Typology to Topography in Clarence King's "Mountaineering in the Sierra Nevada."

    Science.gov (United States)

    Hoekzema, Loren

    The book "Mountaineering in the Sierra Nevada" by Clarence King, a late-ninteenth-century American geologist, writer, art critic, and romantic, is discussed in this paper. In the writing and revision of this book, King was attempting a metamorphosis of landscape description into popular reading as he moved from being a symbolic writer to…

  20. Developing and managing sustainable forest ecosystems for spotted owls in the Sierra Nevada

    Science.gov (United States)

    J. Verner; K.S. McKelvey

    1994-01-01

    Studies of the California spotted owl have revealed significant selection for habitats with large, old trees; relatively high basal areas of snags; and relatively high biomass in large, downed logs. Based on planning documents for national forests in the Sierra Nevada, we projected declining amounts of older-forest attributes. Region 5 has adopted measures to retain...

  1. Holocene glaciation of the central Sierra Nevada, California

    Science.gov (United States)

    Bowerman, Nicole D.; Clark, Douglas H.

    2011-05-01

    Sediment cores from two bedrock-dammed lakes in North Fork Big Pine Creek, Sierra Nevada, California, preserve the most detailed and complete record of Holocene glaciation yet recovered in the region. The lakes are fed by outwash from the Palisade Glacier, the largest (˜1.3 km 2) and presumably longest-lived glacier in the range, and capture essentially all of the rock flour it produces. Distinct late-Holocene (Matthes) and late-Pleistocene (Recess Peak) moraines lie between the modern glacier and the lakes. The lakes have therefore received continuous sedimentation from the basin since the retreat of the Tioga glacier (Last Glacial Maximum) and capture rock flour related to all post-LGM advances. A total of eight long cores (up to 5.5 m sediment depth) and one short surface sediment short core preserve a coherent record of fluctuating rock flour flux to the lakes through the Holocene. Age constraints on rock flour spikes in First and Second lakes based on 31 14C-dated macrofossils indicate Holocene glaciation began ˜3200 cal yr B P, followed by a possible glacier maximum at ˜2800 cal yr B P and four distinct glacier maxima at ˜2200, ˜1600, ˜700 and ˜250-170 cal yr. B.P., the most recent maximum being the largest. Reconstruction of the equilibrium-line altitudes (ELA) associated with each distinct advance recorded in the moraines (Recess Peak, Matthes, and modern) indicates ELA depressions (relative to modern) of ˜250 m and 90 m for Recess Peak and Matthes advances, respectively. These differences represent decreases in summer temperatures of 1.7-2.8 °C (Recess Peak) and 0.2-2° (Matthes), and increases in winter precipitation of 22-34 cm snow water equivalent (s.w.e.) (Recess Peak) and 3-26 cm s.w.e. (Matthes) compared to modern conditions. Although small, these changes are significant and similar to those noted in the Cascade Range to the north, and represent a significant departure from historical climate trends in the region.

  2. Paleozoic and Mesozoic deformations in the central Sierra Nevada, California

    Science.gov (United States)

    Nokleberg, Warren J.; Kistler, Ronald Wayne

    1980-01-01

    Analysis of structural and stratigraphic data indicates that several periods of regional deformation, consisting of combined folding, faulting, cataclasis, and regional metamorphism, occurred throughout the central Sierra Nevada during Paleozoic and Mesozoic time. The oldest regional deformation occurred alono northward trends during the Devonian and Mississippian periods in most roof pendants containing lower Paleozoic metasedimentary rocks at the center and along the crest of the range. This deformation is expressed in some roof pendants by an angular unconformity separating older thrice-deformed from younger twice-deformed Paleozoic metasedimentary rocks. The first Mesozoic deformation, which consisted of uplift and erosion and was accompanied by the onset of Andean-type volcanism during the Permian and Triassic, is expressed by an angular unconformity in several roof pendants from the Saddlebag Lake to the Mount Morrison areas. This unconformity is defined by Permian and Triassic andesitic to rhyolitic metavolcanic rocks unconformably overlying more intensely deformed Pennsylvanian, Permian(?), and older metasedimentary rocks. A later regional deformation occurred during the Triassic along N. 20?_30? W. trends in Permian and Triassic metavolcanic rocks of the Saddlebag Lake and Mount Dana roof pendants, in upper Paleozoic rocks of the Pine Creek roof pendant, and in the Calaveras Formation of the western metamorphic belt; the roof pendants are crosscut by Upper Triassic granitic rocks of the Lee Vining intrusive epoch. A still later period of Early and Middle Jurassic regional deformation occurred along N. 30?-60? E. trends in upper Paleozoic rocks of the Calaveras Formation of the western metamorphic belt. A further period of deformation was the Late Jurassic Nevadan orogeny, which occurred along N. 20?_40? W. trends in Upper Jurassic rocks of the western metamorphic belt that are crosscut by Upper Jurassic granitic rocks of the Yosemite intrusive epoch

  3. Population dynamics of spotted owls in the Sierra Nevada, California

    Science.gov (United States)

    Blakesley, J.A.; Seamans, M.E.; Conner, M.M.; Franklin, A.B.; White, Gary C.; Gutierrez, R.J.; Hines, J.E.; Nichols, J.D.; Munton, T.E.; Shaw, D.W.H.; Keane, J.J.; Steger, G.N.; McDonald, T.L.

    2010-01-01

    The California spotted owl (Strix occidentalis occidentalis) is the only spotted owl subspecies not listed as threatened or endangered under the United States Endangered Species Act despite petitions to list it as threatened. We conducted a meta-analysis of population data for 4 populations in the southern Cascades and Sierra Nevada, California, USA, from 1990 to 2005 to assist a listing evaluation by the United States Fish and Wildlife Service. Our study areas (from N to S) were on the Lassen National Forest (LAS), Eldorado National Forest (ELD), Sierra National Forest (SIE), and Sequoia and Kings Canyon National Parks (SKC). These study areas represented a broad spectrum of habitat and management conditions in these mountain ranges. We estimated apparent survival probability, reproductive output, and rate of population change for spotted owls on individual study areas and for all study areas combined (meta-analysis) using model selection or model-averaging based on maximum-likelihood estimation. We followed a formal protocol to conduct this analysis that was similar to other spotted owl meta-analyses. Consistency of field and analytical methods among our studies reduced confounding methodological effects when evaluating results. We used 991 marked spotted owls in the analysis of apparent survival. Apparent survival probability was higher for adult than for subadult owls. There was little difference in apparent survival between male and female owls. Model-averaged mean estimates of apparent survival probability of adult owls varied from 0.811 ?? 0.021 for females at LAS to 0.890 ?? 0.016 for males at SKC. Apparent survival increased over time for owls of all age classes at LAS and SIE, for adults at ELD, and for second-year subadults and adults at SKC. The meta-analysis of apparent survival, which included only adult owls, confirmed an increasing trend in survival over time. Survival rates were higher for owls on SKC than on the other study areas. We analyzed data

  4. Airborne Pesticides as an Unlikely Cause for Population Declines of Alpine Frogs in the Sierra Nevada, California

    Science.gov (United States)

    Airborne pesticides from the Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the mountain yellow-legged frog complex (Rana muscosa and R. sierrae) in the Sierra Nevada. We measured...

  5. Thymus × pseudogranatensis (Labiatae, nuevo híbrido para Sierra Nevada (España

    Directory of Open Access Journals (Sweden)

    Lorite, Juan

    2011-12-01

    Full Text Available Thymus × pseudogranatensis Vizoso, F.B. Navarro & Lorite, a new spontaneous hybrid of Th. granatensis Boiss. subsp. granatensis and Th. zygis L. subsp. gracilis (Boiss. R. Morales, collected in the dolomitic areas of Sierra Nevada (SE Spain, is described. Morphological characters of the new nothospecies are analysed and its distribution and ecology are discussed.Se describe Thymus × pseudogranatensis Vizoso, F.B. Navarro & Lorite, un nuevo híbrido entre Th. granatensis Boiss. subsp. granatensis y Th. zygis L. subsp. gracilis (Boiss. R. Morales, colectado en la orla dolomítica de Sierra Nevada (SE de España. Se analizan los caracteres morfológicos de la nueva notoespecie y se aportan detalles sobre su hábitat y distribución.

  6. Hydrologic response and watershed sensitivity to climate warming in California's Sierra Nevada.

    Directory of Open Access Journals (Sweden)

    Sarah E Null

    Full Text Available This study focuses on the differential hydrologic response of individual watersheds to climate warming within the Sierra Nevada mountain region of California. We describe climate warming models for 15 west-slope Sierra Nevada watersheds in California under unimpaired conditions using WEAP21, a weekly one-dimensional rainfall-runoff model. Incremental climate warming alternatives increase air temperature uniformly by 2 degrees, 4 degrees, and 6 degrees C, but leave other climatic variables unchanged from observed values. Results are analyzed for changes in mean annual flow, peak runoff timing, and duration of low flow conditions to highlight which watersheds are most resilient to climate warming within a region, and how individual watersheds may be affected by changes to runoff quantity and timing. Results are compared with current water resources development and ecosystem services in each watershed to gain insight into how regional climate warming may affect water supply, hydropower generation, and montane ecosystems. Overall, watersheds in the northern Sierra Nevada are most vulnerable to decreased mean annual flow, southern-central watersheds are most susceptible to runoff timing changes, and the central portion of the range is most affected by longer periods with low flow conditions. Modeling results suggest the American and Mokelumne Rivers are most vulnerable to all three metrics, and the Kern River is the most resilient, in part from the high elevations of the watershed. Our research seeks to bridge information gaps between climate change modeling and regional management planning, helping to incorporate climate change into the development of regional adaptation strategies for Sierra Nevada watersheds.

  7. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain)

    OpenAIRE

    Antonio Jesús Pérez-Luque; Cristina Patricia Sánchez-Rojas; Regino Zamora; Ramón Pérez-Pérez; Francisco Javier Bonet

    2015-01-01

    Abstract Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems...

  8. Correlations and Areal Distribution of the Table Mountain Formation, Stanislaus Group; Central Sierra Nevada, California

    Science.gov (United States)

    Torrez, G.; Carlson, C. W.; Putirka, K. D.; Pluhar, C. J.; Sharma, R. K.

    2011-12-01

    Late Cenozoic evolution of the western Cordillera is a matter of ongoing debate in geologic studies. Volcanic deposits within, and adjacent to the Sierra Nevada have played a significant role in many of these debates. With local faulting coincident with eruption of members of the Stanislaus Group at ca. 38°N, the composition and correlation of these volcanics can greatly aid our understanding of Sierra Nevada tectonics. At the crest of the central Sierra Nevada, 23 trachyandesite lava flows of the Table Mountain Formation, dated at ~10 Ma, cap Sonora Peak. These 23 flows compose the thickest and most complete known stratigraphic section of the Table Mountain Formation in the region. Located ~12 km east of Sonora Peak are 16 flows of trachyandesite at Grouse Meadow. We have collected a detailed set of geochemical and paleomagnetic data for flows of these two sections at Sonora Peak and Grouse Meadows in an attempt to correlate volcanic, paleomagnetic and structural events related to uplift and extension in the Sierra Nevada and the Walker Lane. Correlation of individual flows is possible based on: stratigraphic order, temporal gaps in deposition as determined by paleomagnetic remanence direction and nonconformities, and flow geochemistry. These correlations allow us to infer source localities, flow directions, and temporal changes in flow routes. The large number of flows present at Grouse Meadow provides an additional data set from which to correlate various localities in the region to those units not represented at Sonora Peak. Several flows which occur in the upper portions of the Sonora Peak and Grouse Meadow stratigraphic sections do not correlate between these localities. The causes of stratigraphic discontinuity potentially represent: tectonic isolation across the Sierran Crest, topographic isolation by the emplacement of younger flows, or the combination of the two. Additional to the correlation of individual flows at these localities, this study shows a

  9. Ten Years of Forest Cover Change in the Sierra Nevada Detected Using Landsat Satellite Image Analysis

    Science.gov (United States)

    Potter, Christopher S.

    2014-01-01

    A detailed geographic record of recent vegetation regrowth and disturbance patterns in forests of the Sierra Nevada remains a gap that can be filled with remote sensing data. Landsat (TM) imagery was analyzed to detect 10 years of recent changes (between 2000 and 2009) in forest vegetation cover for areas burned by wildfires between years of 1995 to 1999 in the region. Results confirmed the prevalence of regrowing forest vegetation during the period 2000 and 2009 over 17% of the combined burned areas.

  10. Groundwater quality in the Mokelumne, Cosumnes, and American River Watersheds, Sierra Nevada, California

    Science.gov (United States)

    Fram, Miranda S.; Shelton, Jennifer L.

    2018-03-23

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Program’s Priority Basin Project assesses the quality of groundwater resources used for drinking water supply and increases public access to groundwater-quality information. In the Mokelumne, Cosumnes, and American River Watersheds of the Sierra Nevada, many rural households rely on private wells for their drinking-water supplies.

  11. Resilience Through Disturbance: Effects of Wildfire on Vegetation and Water Balance in the Sierra Nevadas

    Science.gov (United States)

    Boisrame, G. F. S.; Thompson, S. E.; Stephens, S.; Collins, B.; Tague, N.

    2015-12-01

    A century of fire suppression in the Western United States has drastically altered the historically fire-adapated ecology in California's Sierra Nevada Mountains. Fire suppression is understood to have increased the forest cover, as well as the stem density, canopy cover and water demand of montane forests, reducing resilience of the forests to drought, and increasing the risk of catastrophic fire by drying the landscape and increasing fuel loads. The potential to reverse these trends by re-introducing fire into the Sierra Nevada is highly promising, but the likely effects on vegetation structure and water balance are poorly quantified. The Illilouette Creek Basin in Yosemite National Park represents a unique experiment in the Sierra Nevada, in which managers have moved from fire suppression to allowing a near-natural fire regime to prevail since 1972. Changes in vegetation structure in the Illilouette since the restoration of natural burning provides a unique opportunity to examine how frequent, mixed severity fires can reshape the Sierra Nevada landscape. We characterize these changes from 1969 to the present using a combination of Landsat products and high-resolution aerial imagery. We describe how the landscape structure has changed in terms of vegetation composition and its spatial organization, and explore the drivers of different post-fire vegetation type transitions (e.g. forest to shrubland vs. forest to meadow). By upscaling field data using vegetation maps and Landsat wetness indices, we explore how these vegetation transitions have impacted the water balance of the Illilouette Creek Basin, potentially increasing its resilience in the face of drought, climate change, and catastrophic fire. In a region that is adapted to frequent disturbance from fire, this work helps us understand how allowing such natural disturbances to take place can increase the sustainability of diverse landscapes in the long term.

  12. Using machine learning to predict snow water equivalent in the Sierra Nevada USA and Afghanistan

    Science.gov (United States)

    Bair, N.; Rittger, K.; Dozier, J.

    2017-12-01

    In many mountain regions, snowmelt provides most of the runoff. Ranges such as the Sierra Nevada USA benefit from hundreds of manual and automated snow measurement stations as well as basin-wide snow water equavalent (SWE) estimates from new platforms like the Airborne Snow Observatory. Thus, we have been able to use the Sierra Nevada as a testbed to validate an approach called SWE reconstruction, where the snowpack is built-up in reverse using downscaled energy balance forcings. Our past work has shown that SWE reconstruction produces some of the most accurate basin-wide SWE estimates, comparable in accuracy to a snow pillow/course interpolation, but requires no in situ measurements, which is its main advantage. The disadvantages are that reconstruction cannot be used for a forecast and is only valid during the ablation period. To address these shortcomings, we have used machine learning trained on reconstructed SWE in the Sierra Nevada and Afghanistan, where there are no accessible snowpack measurements. Predictors are physiographic and remotely-sensed variables, including brightness temperatures from a new enhanced resolution passive microwave dataset. Two machine learning techniques—bagged regression trees and feed-forward neural networks—were used. Results show little bias on average and training period, i.e. the ablation period.

  13. Spatiotemporal patterns of fault slip rates across the Central Sierra Nevada frontal fault zone

    Science.gov (United States)

    Rood, Dylan H.; Burbank, Douglas W.; Finkel, Robert C.

    2011-01-01

    Patterns in fault slip rates through time and space are examined across the transition from the Sierra Nevada to the Eastern California Shear Zone-Walker Lane belt. At each of four sites along the eastern Sierra Nevada frontal fault zone between 38 and 39° N latitude, geomorphic markers, such as glacial moraines and outwash terraces, are displaced by a suite of range-front normal faults. Using geomorphic mapping, surveying, and 10Be surface exposure dating, mean fault slip rates are defined, and by utilizing markers of different ages (generally, ~ 20 ka and ~ 150 ka), rates through time and interactions among multiple faults are examined over 10 4-10 5 year timescales. At each site for which data are available for the last ~ 150 ky, mean slip rates across the Sierra Nevada frontal fault zone have probably not varied by more than a factor of two over time spans equal to half of the total time interval (~ 20 ky and ~ 150 ky timescales): 0.3 ± 0.1 mm year - 1 (mode and 95% CI) at both Buckeye Creek in the Bridgeport basin and Sonora Junction; and 0.4 + 0.3/-0.1 mm year - 1 along the West Fork of the Carson River at Woodfords. Data permit rates that are relatively constant over the time scales examined. In contrast, slip rates are highly variable in space over the last ~ 20 ky. Slip rates decrease by a factor of 3-5 northward over a distance of ~ 20 km between the northern Mono Basin (1.3 + 0.6/-0.3 mm year - 1 at Lundy Canyon site) to the Bridgeport Basin (0.3 ± 0.1 mm year - 1 ). The 3-fold decrease in the slip rate on the Sierra Nevada frontal fault zone northward from Mono Basin is indicative of a change in the character of faulting north of the Mina Deflection as extension is transferred eastward onto normal faults between the Sierra Nevada and Walker Lane belt. A compilation of regional deformation rates reveals that the spatial pattern of extension rates changes along strike of the Eastern California Shear Zone-Walker Lane belt. South of the Mina Deflection

  14. Potential increase in floods in California's Sierra Nevada under future climate projections

    Science.gov (United States)

    Das, T.; Dettinger, M.D.; Cayan, D.R.; Hidalgo, H.G.

    2011-01-01

    California's mountainous topography, exposure to occasional heavily moisture-laden storm systems, and varied communities and infrastructures in low lying areas make it highly vulnerable to floods. An important question facing the state-in terms of protecting the public and formulating water management responses to climate change-is "how might future climate changes affect flood characteristics in California?" To help address this, we simulate floods on the western slopes of the Sierra Nevada Mountains, the state's primary catchment, based on downscaled daily precipitation and temperature projections from three General Circulation Models (GCMs). These climate projections are fed into the Variable Infiltration Capacity (VIC) hydrologic model, and the VIC-simulated streamflows and hydrologic conditions, from historical and from projected climate change runs, allow us to evaluate possible changes in annual maximum 3-day flood magnitudes and frequencies of floods. By the end of the 21st Century, all projections yield larger-than-historical floods, for both the Northern Sierra Nevada (NSN) and for the Southern Sierra Nevada (SSN). The increases in flood magnitude are statistically significant (at p models, while under the third scenario, GFDL CM2. 1, frequencies remain constant or decline slightly, owing to an overall drying trend. These increases appear to derive jointly from increases in heavy precipitation amount, storm frequencies, and days with more precipitation falling as rain and less as snow. Increases in antecedent winter soil moisture also play a role in some areas. Thus, a complex, as-yet unpredictable interplay of several different climatic influences threatens to cause increased flood hazards in California's complex western Sierra landscapes. ?? 2011 Springer Science+Business Media B.V.

  15. High Compressive Stresses Near the Surface of the Sierra Nevada, California

    Science.gov (United States)

    Martel, S. J.; Logan, J. M.; Stock, G. M.

    2012-12-01

    Observations and stress measurements in granitic rocks of the Sierra Nevada, California reveal strong compressive stresses parallel to the surface of the range at shallow depths. New overcoring measurements show high compressive stresses at three locations along an east-west transect through Yosemite National Park. At the westernmost site (west end of Tenaya Lake), the mean compressive stress is 1.9. At the middle site (north shore of Tenaya Lake) the mean compressive stress is 6.8 MPa. At the easternmost site (south side of Lembert Dome) the mean compressive stress is 3.0 MPa. The trend of the most compressive stress at these sites is within ~30° of the strike of the local topographic surface. Previously published hydraulic fracturing measurements by others elsewhere in the Sierra Nevada indicate surface-parallel compressive stresses of several MPa within several tens of meters of the surface, with the stress magnitudes generally diminishing to the west. Both the new and the previously published compressive stress magnitudes are consistent with the presence of sheeting joints (i.e., "exfoliation joints") in the Sierra Nevada, which require lateral compressive stresses of several MPa to form. These fractures are widespread: they are distributed in granitic rocks from the north end of the range to its southern tip and across the width of the range. Uplift along the normal faults of the eastern escarpment, recently measured by others at ~1-2 mm/yr, probably contributes to these stresses substantially. Geodetic surveys reveal that normal faulting flexes a range concave upwards in response to fault slip, and this flexure is predicted by elastic dislocation models. The topographic relief of the eastern escarpment of the Sierra Nevada is 2-4 km, and since alluvial fill generally buries the bedrock east of the faults, the offset of granitic rocks is at least that much. Compressive stresses of several MPa are predicted by elastic dislocation models of the range front

  16. Isotopes and ages in the northern Peninsular Ranges batholith, southern California

    Science.gov (United States)

    Kistler, Ronald W.; Wooden, Joseph L.; Morton, Douglas M.

    2003-01-01

    Strontium, oxygen and lead isotopic and rubidium-strontium geochronologic studies have been completed on Cretaceous and Jurassic (?) granitic rock samples from the northern Peninsular Ranges batholith in southern California. Many of these samples were collected systematically and studied chemically by A. K. Baird and colleagues (Baird and others, 1979). The distribution of these granitic rocks is shown in the Santa Ana, Perris, and San Jacinto Blocks, bounded by the Malibu Coast-Cucamonga, Banning, and San Andreas fault zones, and the Pacific Ocean on the map of the Peninsular Ranges batholith and surrounding area, southern California. The granitic rock names are by Baird and Miesch (1984) who used a modal mineral classification that Bateman and others (1963) used for granitic rocks in the Sierra Nevada batholith. In this classification, granitic rocks have at least 10% quartz. Boundaries between rock types are in terms of the ratio of alkali-feldspar to total feldspar: quartz diorite, 0-10%; granodiorite, 10-35%; quartz monzonite 35-65%; granite >65%. Gabbros have 0-10% quartz. Data for samples investigated are giv in three tables: samples, longitude, latitude, specific gravity and rock type (Table 1); rubidium and strontium data for granitic rocks of the northern Peninsular Ranges batholith, southern California (Table 2); U, Th, Pb concentrations, Pb and Sr initial isotopic compositions, and δ18O permil values for granitic rocks of the northern Peninsular Ranges batholith (table 3).

  17. Climate controls on forest productivity along the climate gradient of the western Sierra Nevada

    Science.gov (United States)

    Kelly, A. E.; Goulden, M. L.

    2010-12-01

    The broad climate gradient of the slopes of the western Sierra Nevada mountains supports ecosystems spanning extremes of productivity, biomass, and function. We are using this natural environmental gradient to understand how climate controls NPP, aboveground biomass, species' range limits, and phenology. Our experimental approach combines eddy covariance, sap flow, dendrometer, and litterfall measurements in combination with soil and hydrological data from the Southern Sierra Critical Zone Observatory (SSCZO). We have found that above about 2500 m, forest productivity is limited by winter cold, while below 1200 m, productivity is likely limited by summer drought. The sweet spot between these elevations has a nearly year-long growing season despite a snowpack that persists for as long as six months. Our results show that small differences in temperature can markedly alter the water balance and productivity of mixed conifer forests.

  18. Potential environmental effects of pack stock on meadow ecosystems of the Sierra Nevada, USA

    Science.gov (United States)

    Ostoja, Steven M.; Brooks, Matthew L.; Moore, Peggy E.; Berlow, Eric L.; Robert Blank,; Roche, Jim; Chase, Jennifer T.; Sylvia Haultain,

    2014-01-01

    Pack and saddle stock, including, but not limited to domesticated horses, mules, and burros, are used to support commercial, private and administrative activities in the Sierra Nevada. The use of pack stock has become a contentious and litigious issue for land management agencies in the region inter alia due to concerns over effects on the environment. The potential environmental effects of pack stock on Sierra Nevada meadow ecosystems are reviewed and it is concluded that the use of pack stock has the potential to influence the following: (1) water nutrient dynamics, sedimentation, temperature, and microbial pathogen content; (2) soil chemistry, nutrient cycling, soil compaction and hydrology; (3) plant individuals, populations and community dynamics, non-native invasive species, and encroachment of woody species; and (4) wildlife individuals, populations and communities. It is considered from currently available information that management objectives of pack stock should include the following: minimise bare ground, maximise plant cover, maintain species composition of native plants, minimise trampling, especially on wet soils and stream banks, and minimise direct urination and defecation by pack stock into water. However, incomplete documentation of patterns of pack stock use and limited past research limits current understanding of the effects of pack stock, especially their effects on water, soils and wildlife. To improve management of pack stock in this region, research is needed on linking measurable monitoring variables (e.g. plant cover) with environmental relevancy (e.g. soil erosion processes, wildlife habitat use), and identifying specific environmental thresholds of degradation along gradients of pack stock use in Sierra Nevada meadows.

  19. Ozone distribution in remote ecologically vulnerable terrain of the southern Sierra Nevada, CA

    International Nuclear Information System (INIS)

    Panek, Jeanne; Saah, David; Esperanza, Annie; Bytnerowicz, Andrzej; Fraczek, Witold; Cisneros, Ricardo

    2013-01-01

    Ozone concentration spatial patterns remain largely uncharacterized across the extensive wilderness areas of the Sierra Nevada, CA, despite being downwind of major pollution sources. These natural areas, including four national parks and four national forests, contain forest species that are susceptible to ozone injury. Forests stressed by ozone are also more vulnerable to other agents of mortality, including insects, pathogens, climate change, and ultimately fire. Here we analyze three years of passive ozone monitor data from the southern Sierra Nevada and interpolate landscape-scale spatial and temporal patterns during the summer-through-fall high ozone concentration period. Segmentation analysis revealed three types of ozone exposure sub-regions: high, low, and variable. Consistently high ozone exposure regions are expected to be most vulnerable to forest mortality. One high exposure sub-region has been documented elsewhere as being further vulnerable to increased drought and fire potential. Identifying such hot-spots of forest vulnerability has utility for prioritizing management. -- Highlights: •Three years of passive ozone sampler data over 49,000 km 2 were analyzed spatially. •Spatial and temporal ozone patterns were mapped across the Sierra Nevada, CA. •Sub-regions of consistently high, low and variable ozone exposure were identified. •The 1700–2400 m elevation band delineated a distinct break in ozone concentration. •This approach has utility for prioritizing management across vulnerable landscapes. -- A passive ozone sampler network in combination with spatial analysis techniques was used to characterize landscape-scale ozone patterns and dynamics, identifying regions of consistently high and low ozone exposure for forest management prioritization

  20. Data on snow chemistry of the Cascade-Sierra Nevada Mountains

    Science.gov (United States)

    Laird, L.B.; Taylor, Howard E.; Lombard, R.E.

    1986-01-01

    Snow chemistry data were measured for solutes found in snow core samples collected from the Cascade-Sierra Nevada Mountains from late February to mid-March 1983. The data are part of a study to assess geographic variations in atmospheric deposition in Washington, Oregon, and California. The constituents and properties include pH and concentrations of hydrogen ion, calcium, magnesium, sodium, potassium, chloride, sulfate, nitrate, fluoride, phosphate, ammonium, iron, aluminum, manganese, copper, cadmium, lead, and dissolved organic carbon. Concentrations of arsenic and bromide were below the detection limit. (USGS)

  1. Groundwater quality in the Yuba River and Bear River Watersheds, Sierra Nevada, California

    Science.gov (United States)

    Fram, Miranda S.; Jasper, Monica; Taylor, Kimberly A.

    2017-09-27

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Program’s Priority Basin Project assesses the quality of groundwater resources used for drinking water supply and increases public access to groundwater-quality information. In the Yuba River and Bear River Watersheds of the Sierra Nevada, many rural households rely on private wells for their drinking water supplies. 

  2. Ecología de la fauna silvestre de la sierra nevada y la Sierra del Ajusco

    Directory of Open Access Journals (Sweden)

    D. Granados Sánchez

    2004-01-01

    Full Text Available Se presenta un estudio sobre la fauna silvestre de la Sierra del Ajusco y la Sierra Nevada, localizadas dentro de la Faja Volcánica Transmexicana (FVT, en la porción oriental del límite meridional de la Cuenca de México. La enorme riqueza biológica de esta zona que rodea la zona metropolitana de la ciudad de México, uno de los mayores complejos urbanos del mundo, ha sobrevivido durante décadas al impacto de la urbanización de las áreas forestales, explotación de recursos naturales, contaminación, cacería, incendios y pastoreo. A pesar de esto, se desconocen muchos de los factores que regulan la dinámica de los ecosistemas en esta región. Con relación a la fauna silvestre la carencia de información es mucho más evidente, aspectos elementales como la diversidad de especies, las interacciones ecológicas, la función de los organismos en el ecosistema, las condiciones de estrés a que están sometidos, han sido poco explorados. En esta investigación se recurrió a observaciones de campo y a la consulta de diferentes fuentes bibliográficas para estimar la riqueza de especies de mamíferos, aves, reptiles y anfibios; las relaciones ecológicas entre los mismos y las consecuencias de la modificación de su hábitat producto de las actividades humanas.

  3. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain)

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Sánchez-Rojas, Cristina Patricia; Zamora, Regino; Pérez-Pérez, Ramón; Bonet, Francisco Javier

    2015-01-01

    Abstract Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988–1990 and 2009–2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area. PMID:25878552

  4. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain).

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Sánchez-Rojas, Cristina Patricia; Zamora, Regino; Pérez-Pérez, Ramón; Bonet, Francisco Javier

    2015-01-01

    Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988-1990 and 2009-2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area.

  5. High-Elevation Sierra Nevada Conifers Reveal Increasing Reliance on Snow Water with Changing Climate

    Science.gov (United States)

    Lepley, K. S.; Meko, D. M.; Touchan, R.; Shamir, E.; Graham, R.

    2017-12-01

    Snowpack in the Sierra Nevada Mountains accounts for around one third of California's water supply. Melting snow can provide water into dry summer months characteristic of the region's Mediterranean climate. As climate changes, understanding patterns of snowpack, snowmelt, and biological response are critical in this region of agricultural, recreational, and ecological value. Tree rings can act as proxy records to inform scientists and resource managers of past climate variability where instrumental data is unavailable. Here we investigate relationships between tree rings of high-elevation, snow-adapted conifer trees (Tsuga mertensiana, Abies magnifica) and April 1st snow-water equivalent (SWE) in the northern Sierra Nevada Mountains. The 1st principal component of 29 highly correlated regional SWE time series was modeled using multiple linear regression of four tree-ring chronologies including two lagged chronologies. Split-period verification analysis of this model revealed poor predictive skill in the early half (1929 - 1966) of the calibration period (1929 - 2003). Further analysis revealed a significant (p time. Snow water is becoming a more limiting resource to tree growth as average temperatures rise and the hydrologic regime shifts. These results highlight the need for resource managers and policy makers to consider that biological response to climate is not static.

  6. Fumio Matsumura--accomplishments at the University of California, Davis, and in the Sierra Nevada Mountains.

    Science.gov (United States)

    Seiber, James N

    2015-05-01

    Fumio Matsumura joined the University of California, Davis, faculty in 1987 where he served as founding director of the Center for Environmental Health Sciences, associate director of the U.C. Toxic Substances Research and Teaching Program, and chair of the Department of Environmental Toxicology. He was an active affiliate with the NIEHS-funded Superfund Basic Research Program and the NIH Comprehensive Cancer Center. He was in many instances a primary driver or otherwise involved in most activities related to environmental toxicology at Davis, including the education of students in environmental biochemistry and ecotoxicology. A significant part of his broad research program was focused on the long range transport of chemicals such as toxaphene, PCBs and related contaminants used or released in California to the Sierra Nevada mountains, downwind of the urban and agricultural regions of the state. He hypothesized that these chemical residues adversely affected fish and wildlife, and particularly the declining populations of amphibians in Sierra Nevada streams and lakes. Fumio and his students and colleagues found residues of toxaphene and PCBs at higher elevations, an apparent result of atmospheric drift and deposition in the mountains. Fumio and his wife Teruko had personal interests in, and a love of the mountains, as avid skiers, hikers, and outdoor enthusiasts. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Vertical Distribution of Ozone and Nitric Acid Vapor on the Mammoth Mountain, Eastern Sierra Nevada, California

    Directory of Open Access Journals (Sweden)

    Andrzej Bytnerowicz

    2002-01-01

    Full Text Available In August and September 1999 and 2000, concentrations of ozone (O3 and nitric acid vapor (HNO3 were monitored at an elevation gradient (2184–3325 m on the Mammoth Mountain, eastern Sierra Nevada, California. Passive samplers were used for monitoring exposure to tropospheric O3 and HNO3 vapor. The 2-week average O3 concentrations ranged between 45 and 72 ppb, while HNO3 concentrations ranged between 0.06 and 0.52 μg/m3. Similar ranges of O3 and HNO3 were determined for 2 years of the study. No clear effects of elevation on concentrations of the two pollutants were detected. Concentrations of HNO3 were low and at the background levels expected for the eastern Sierra Nevada, while the measured concentrations of O3 were elevated. High concentrations of ozone in the study area were confirmed with an active UV absorption O3 monitor placed at the Mammoth Mountain Peak (September 5–14, 2000, average 24-h concentration of 56 ppb.

  8. Cenozoic thermal evolution of the central Sierra Nevada, California, from (U sbnd Th)/He thermochronometry

    Science.gov (United States)

    House, M. A.; Wernicke, B. P.; Farley, K. A.; Dumitru, T. A.

    1997-10-01

    Apatite(U sbnd Th)/He cooling ages are reported for igneous apatite samples from the central Sierra Nevada and compared to published apatite fission track ages and track length data from the same mineral separates. Helium ages are youngest at low elevations and increase systematically toward higher elevations, ranging from 43 to 84 Ma at Yosemite Valley, 32 to 74 Ma at Kings River Canyon, and 23 to 75 Ma at Mt. Whitney. Helium ages from high elevation samples are generally concordant with corresponding fission track ages, while lower elevation helium ages are substantially younger. Cooling histories inferred from present laboratory derived fission track annealing and helium diffusion models do not match well, suggesting that either helium diffusion rates or fission track annealing rates are miscalibrated at temperatures below about 60°C for geologic exposure periods. Unlike the fission track results, the helium data do not indicate a very low geothermal gradient in the Sierra Nevada during early to middle Tertiary time.

  9. Tracking magmatic processes through Zr/Hf ratios in rocks and Hf and Ti zoning in zircons: An example from the Spirit Mountain batholith, Nevada

    Science.gov (United States)

    Lowery, Claiborne L.E.; Miller, C.F.; Walker, B.A.; Wooden, J.L.; Mazdab, F.K.; Bea, F.

    2006-01-01

    Zirconium and Hf are nearly identical geochemically, and therefore most of the crust maintains near-chondritic Zr/Hf ratios of ???35-40. By contrast, many high-silica rhyolites and granites have anomalously low Zr/Hf (15-30). As zircon is the primary reservoir for both Zr and Hf and preferentially incorporates Zr, crystallization of zircon controls Zr/ Hf, imprinting low Zr/Hf on coexisting melt. Thus, low Zr/Hf is a unique fingerprint of effective magmatic fractionation in the crust. Age and compositional zonation in zircons themselves provide a record of the thermal and compositional histories of magmatic systems. High Hf (low Zr/ Hf) in zircon zones demonstrates growth from fractionated melt, and Ti provides an estimate of temperature of crystallization (TTiZ) (Watson and Harrison, 2005). Whole-rock Zr/Hf and zircon zonation in the Spirit Mountain batholith, Nevada, document repeated fractionation and thermal fluctuations. Ratios of Zr/Hf are ???30-40 for cumulates and 18-30 for high-SiO2 granites. In zircons, Hf (and U) are inversely correlated with Ti, and concentrations indicate large fluctuations in melt composition and TTiZ (>100??C) for individual zircons. Such variations are consistent with field relations and ion-probe zircon geochronology that indicate a >1 million year history of repeated replenishment, fractionation, and extraction of melt from crystal mush to form the low Zr/Hf high-SiO2 zone. ?? 2006 The Mineralogical Society.

  10. 77 FR 45 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List Sierra Nevada...

    Science.gov (United States)

    2012-01-03

    ... them at risk of attack, death, or diseases such as rabies, sarcoptic mange, canine distemper, and... canine distemper, rabies, and sarcoptic mange to Sierra Nevada red fox (Perrine et al. 2010, p. 28... 2011, pp. 54-60), an outbreak of canine distemper or other lethal disease, as well as predation by...

  11. REGIONAL ANALYSIS OF INORGANIC NITROGEN YIELD AND RETENTION IN HIGH-ELEVATION ECOSYSTEMS OF THE SIERRA NEVADA AND ROCKY MOUNTAINS

    Science.gov (United States)

    Yields and retention of inorganic nitrogen (DIN) and nitrate concentrations in surface runoff are summarized for 28 high elevation watersheds in the Sierra Nevada, California and Rocky Mountains of Wyoming and Colorado. Catchments ranged in elevation from 2475 to 3603 m and from...

  12. Ozone, nitric acid, and ammonia air pollution is unhealthy for people and ecosystems in southern Sierra Nevada, California

    Science.gov (United States)

    R. Cisneros; A. Bytnerowicz; D. Schweizer; S. Zhong; S. Traina; D.H. Bennett

    2010-01-01

    Two-week average concentrations of ozone (O3), nitric acid vapor (HNO3) and ammonia (NH3) were measured with passive samplers during the 2002 summer season across the central Sierra Nevada Mountains, California, along the San Joaquin River drainage. Elevated concentrations of the pollutants were...

  13. Modeling the influence of precipitation and nitrogen deposition on forest understory fuel connectivity in Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    M. Hurteau; M. North; T. Foines

    2009-01-01

    Climate change models for California’s Sierra Nevada predict greater inter-annual variability in precipitation over the next 50 years. These increases in precipitation variability coupled with increases in nitrogen deposition fromfossil fuel consumption are likely to result in increased productivity levels and significant increases in...

  14. First record for the river turtle Kinosternon leucostomum (DUMERIL & BIBRON 1851, from the Sierra Nevada de Santa Marta foothills

    Directory of Open Access Journals (Sweden)

    Juan Mendoza Roldan

    2017-07-01

    Full Text Available The river turtle (Kinosternon leucostomum, was first reported for the department of Guajira in 2011, found in the foothills of the Serranía de Perijá (GALVIS-PEÑUELA et al., 2011. Our observations constitute the first record for the Sierra Nevada de Santamarta Massif and the second distribution record within the department of Guajira, Colombian Caribbean.

  15. Multi-scale evaluation of the environmental controls on burn probability in a southern Sierra Nevada landscape

    Science.gov (United States)

    Sean A. Parks; Marc-Andre Parisien; Carol Miller

    2011-01-01

    We examined the scale-dependent relationship between spatial fire likelihood or burn probability (BP) and some key environmental controls in the southern Sierra Nevada, California, USA. Continuous BP estimates were generated using a fire simulation model. The correspondence between BP (dependent variable) and elevation, ignition density, fuels and aspect was evaluated...

  16. Content of chemical elements in tree rings of lodgepole pine and whitebark pine from a subalpine Sierra Nevada forest

    Science.gov (United States)

    David L. Peterson; Darren R. Anderson

    1990-01-01

    The wood of lodgepole pines and whitebark pines from a high elevation site in the east central Sierra Nevada of California was analyzed for chemical content to determine whether there were any temporal patterns of chemical distribution in tree rings. Cores were taken from 10 trees of each species and divided into 5-year increments for chemical analysis. Correlation...

  17. Assessing the spatial variability of mountain precipitation in California's Sierra Nevada using the Airborne Snow Observatory

    Science.gov (United States)

    Brandt, T.; Deems, J. S.; Painter, T. H.; Dozier, J.

    2016-12-01

    In California's Sierra Nevada, 10 or fewer winter storms are responsible for most of the annual precipitation, which falls mostly as snow. Presently, surface stations are used to measure the dynamics of mountain precipitation. However, even in places like the Sierra Nevada—one of the most gauged regions in the world—the paucity of surface stations can lead to large errors in precipitation thereby biasing both total water year and short-term streamflow forecasts. Remotely sensed snow depth and water equivalent, at a time scale that resolves storms, might provide a novel solution to the problems of: (1) quantifying the spatial variability of mountain precipitation; and (2) assessing gridded precipitation products that are mostly based on surface station interpolation. NASA's Airborne Snow Observatory (ASO), an imaging spectrometer and LiDAR system, has measured snow in the Tuolumne River Basin in California's Sierra Nevada for the past four years, 2013-2016; and, measurements will continue. Principally, ASO monitors the progression of melt for water supply forecasting, nonetheless, a number of flights bracketed storms allowing for estimates of snow accumulation. In this study we examine a few of the ASO recorded storms to determine both the basin and subbasin orographic effect as well as the spatial patterns in total precipitation. We then compare these results to a number of gridded climate products and weather models including: Daymet, the Parameter-elevation Regressions on Independent Slopes Model (PRISM), the North American Land Data Assimilation System (NLDAS-2), and the Weather Research and Forecasting (WRF) model. Finally, to put each ASO recorded storm into context, we use a climatology produced from snow pillows and the North American Regional Reanalysis (NARR) for 2014-2016 to examine key accumulation events, and classify storms based on their integrated water vapor flux.

  18. Clustering of velocities in a GPS network spanning the Sierra Nevada Block, the northern Walker Lane Belt, and the Central Nevada Seismic Belt, California-Nevada

    Science.gov (United States)

    Savage, James C.; Simpson, Robert W.

    2013-01-01

    The deformation across the Sierra Nevada Block, the Walker Lane Belt, and the Central Nevada Seismic Belt (CNSB) between 38.5°N and 40.5°N has been analyzed by clustering GPS velocities to identify coherent blocks. Cluster analysis determines the number of clusters required and assigns the GPS stations to the proper clusters. The clusters are shown on a fault map by symbols located at the positions of the GPS stations, each symbol representing the cluster to which the velocity of that GPS station belongs. Fault systems that separate the clusters are readily identified on such a map. Four significant clusters are identified. Those clusters are strips separated by (from west to east) the Mohawk Valley-Genoa fault system, the Pyramid Lake-Wassuk fault system, and the Central Nevada Seismic Belt. The strain rates within the westernmost three clusters approximate simple right-lateral shear (~13 nstrain/a) across vertical planes roughly parallel to the cluster boundaries. Clustering does not recognize the longitudinal segmentation of the Walker Lane Belt into domains dominated by either northwesterly trending, right-lateral faults or northeasterly trending, left-lateral faults.

  19. Plan for a Sierra Nevada Hydrologic Observatory: Science Aims, Measurement Priorities, Research Opportunities and Expected Impacts

    Science.gov (United States)

    Bales, R.; Dozier, J.; Famiglietti, J.; Fogg, G.; Hopmans, J.; Kirchner, J.; Meixner, T.; Molotch, N.; Redmond, K.; Rice, R.; Sickman, J.; Warwick, J.

    2004-12-01

    In response to NSF's plans to establish a network of hydrologic observatories, a planning group is proposing a Sierra Nevada Hydrologic Observatory (SNHO). As argued in multiple consensus planning documents, the semi-arid mountain West is perhaps the highest priority for new hydrologic understanding. Based on input from over 100 individuals, it is proposed to initiate a mountain-range-scale study of the snow-dominated hydrology of the region, focusing on representative 1,000-5,000 km2 river basins originating in the Sierra Nevada and tributary to the Sacramento-San-Joaquin Delta. The SNHO objective is to provide the necessary infrastructure for improved understanding of surface-water and ground-water systems, their interactions and their linkages with ecosystems, biogeochemistry, agriculture, urban areas and water resources in semi-arid regions. The SNHO will include east-west transects of hydrological observations across the Sierra Nevada and into the basin and range system, in four distinct latitude bands that span much of the variability found in the semi-arid West. At least one transect will include agricultural and urban landscapes of the Great Central Valley. Investments in measurement systems will address scales from the mountain range down to the basin, headwater catchment and study plot. The intent is to provide representative measurements that will yield general knowledge as opposed to site-specific problem solving of a unique system. The broader, general science question posed by the planning group is: How do mountain hydrologic processes vary across landscapes, spanning a range of latitudes, elevations and thus climate, soils, geology and vegetation zones?\\" Embodied are additional broad questions for the hydrologic science community as a whole: (i) How do hydrologic systems that are subjected to multiple perturbations respond? (ii) How do pulses and changes propagate through the hydrologic system? (iii) What are the time lags and delays of stresses in

  20. Sierra Nevada serpentinites. An important element in the architectonic heritage of Granada (Spain).

    Science.gov (United States)

    Navarro, Rafael; Pereira, Dolores; Rodríguez-Navarro, Carlos; Sebastián-Pardo, Eduardo

    2013-04-01

    Serpentinites are widely used in historic buildings in the whole world, from Ancient Greek or Egypt to more recent colonial buildings in the USA. Serpentinites from Sierra Nevada (S of Spain) have been traditionally used as ornamental elements in historic buildings of Granada city, both indoors and outdoors. The Cathedral, Carlos V Palace, Royal Chancery and some others are good examples of their use. Some other important cases can be found outside Granada, like El Escorial monastery, Las Salesas Reales convent, etc… all of them part of Madrid architectonic heritage. There are two quarries located in Sierra Nevada that supplied all the material to make the different elements in the cited buildings. In this work, a thorough characterization of the main serpentinites from Sierra Nevada, their uses, and their state of conservation in selected buildings from Granada has been performed. Samples from the main original quarry and from one historical building (Real Chancillería) have been analysed, determining the mineralogical and geochemical composition, texture, water parameters (absorption, porosity, density) and possible alteration by salt formation. It has been observed that the mineralogical and geochemical compositions are similar in both sets of samples, although the ones coming from the historical building show a highly advanced state of alteration. Regarding physical and mechanical parameters, samples from the quarry have very low water absorption values, while the porosity of serpentinites sampled from the Real Chancillería is comparatively much higher. We explain this difference as due to the weathering of the emplaced serpentinites by salt crystallization processes (mainly gypsum or epsomite), that generate strong internal pressures causing the disintegration of the whole natural stone. In addition, the increase of the porosity can be caused by dissolution processes related to the presence of acid solutions related to oxidation and hydrolysis of iron

  1. Mineralogy and geochemistry of two metamorphosed sedimentary manganese deposits, Sierra Nevada, California, USA

    Science.gov (United States)

    Flohr, M.J.K.; Huebner, J.S.

    1992-01-01

    Laminated to massive rhodochrosite, hausmannite, and Mn-silicates from the Smith prospect and Manga-Chrome mine, Sierra Nevada, California were deposited as ocean floor sediments associated with chert and shale. The principal lithologies at Smith are chert, argillite, rhodochrosite-, hausmannite- and chlorite-rich layers, and relatively uncommon layers of jacobsite. The Manga-Chrome mine also contains layers rich in manganoan calcite and caryopilite. Tephroite, rhodonite, spessartine, and accessory alleghanyite and sonolite formed during metamorphism. Volcaniclastic components are present at Manga-Chrome as metavolcanic clasts and as Mn-poor, red, garnet- and hematite-rich layers. There is no evidence, such as relict lithologies, that Mn was introduced into Mn-poor lithologies such as chert, limestone or mudstone. Replacement of Mn-poor phases by Mn-rich phases is observed only in the groundmass of volcanic clasts that appear to have fallen into soft Mn-rich mud. Manganiferous samples from the Smith prospect and Manga-Chrome mine have high Mn Fe and low concentrations of Ni, Cu, Zn, Co, U, Th and the rare-earth elements that are similar to concentrations reported from other ancient Mn deposits found in chert-greenstone complexes and from manganiferous sediments and crusts that are forming near modern sea floor vents. The Sierra Nevada deposits formed as precipitates of Mn-rich sediments on the sea floor, probably from mixtures of circulating hydrothermal fluids and seawater. The composition of a metabasalt from the Smith prospect is consistent with those of island-arc tholeiites. Metavolcanic clasts from the Manga-Chrome mine are compositionally distinct from the Smith metabasalt and have alkaline to calc-alkaline affinities. A back-arc basin is considered to be the most likely paleoenvironment for the formation of the Mn-rich lenses at the Manga-Chrome mine and, by association, the Smith prospect. Layers of rhodochrosite, hausmannite and chert preserve the

  2. Making up for lost snow: lessons from a warming Sierra Nevada

    Science.gov (United States)

    Bales, R. C.

    2017-12-01

    Snowpack- and glacier-dependent river basins are home to over 1.2 billion people, one-sixth of the world's current population. These areas face severe challenges in a warmer climate, as declines in snow resources put more pressure on dams and groundwater. Closer to home, the seasonal snowpacks in California's Sierra Nevada provide water storage to both sustain productive forests and support the world's 6th largest economy. Rivers draining the Sierra supply the state's large cities, plus agricultural areas that provide nearly half of the nation's fruits and vegetables. Water storage is central to water security, especially given California's hot dry summers and high interannual variability in precipitation. On average seasonal snowpacks store about half as much water as do dams on Sierra rivers; and both the magnitude and duration of snowpack storage are decreasing. Precipitation amount and snow accumulation across the mountains in any given day, month or year remain uncertain. As historical index-statistical methods for hydrologic forecasts give way to tools based on mass and energy balances distributed across the landscape, opportunities are arising to broadly implement spatial measurements of snowpack storage and the equally important regolith-water storage. Advances in applying satellite and aircraft remote sensing, plus spatially distributed wireless-sensor networks, are filling this need. These same unprecedented data are driving process understanding to improve knowledge of snow-energy-forest interactions, snowmelt estimates, and hydrologic forecasts for hydropower, water supply, and flood control. Estimating the value of snowpacks and how they are changing provides a baseline for evaluating investments in restoration of headwater forests that will affect snowmelt runoff, and in providing replacement storage as snow declines. With California facing billions of dollars of green and grey infrastructure improvements, which must be compatible with the state

  3. Some additional observations on inclusions in the granitic rocks of the Sierra Nevada

    Science.gov (United States)

    Dodge, F.C.W.; Kistler, R.W.

    1990-01-01

    Microgranular quartz diorite and diorite inclusions are widespread in central Sierra Nevada granitoid rocks and are almost exclusively restricted to hornblende-bearing rocks, most commonly felsic tonalites and mafic granodiorites. The Nd-Sm and Rb-Sr systematics indicate that most inclusions were in isotopic equilibrium with enclosing materials at the time of formation. Silica contents of inclusions and granitoids are contiguous, but inclusions generally contain less than, and granitoids more than, 60% SiO2. Ferric oxide and H2O+ trends relative to SiO2 suggests many inclusions formed as concentrations of hydrous mafic minerals. Variation of other major element oxides and trace elements support this inference. Most inclusions represent fragmented crystal accumulations of early-formed, near-liquidus minerals generated from these previously mixed magmas. -from Authors

  4. Inevitable changes in snowpack and water resources over California's Sierra Nevada

    Science.gov (United States)

    Hall, A. D.; Sun, F.; Walton, D.; Berg, N.; Schwartz, M. A.

    2015-12-01

    Here we use a downscaling technique incorporating both dynamical and statistical methods to project end-of-century changes in spring snow water equivalent in California's Sierra Nevada. The technique produces outcomes for all Global Climate Models (GCMs) and the four greenhouse gas forcing scenarios adopted by the Intergovernmental Panel on Climate Change (IPCC). For all GCMs and forcing scenarios, significant snow loss occurs at elevations below 2500 meters, despite increasing precipitation in many GCMs. The loss is significantly enhanced by snow albedo feedback. The approximate intermodel range in percent of total snow remaining in the entire region is 60-85% for a likely "mitigation" scenario, and 35-55% for the "business-as-usual" scenario. Thus significant snowpack decrease by century's end is inevitable, even if the loss can be cushioned through greenhouse gas emissions reductions over the coming decades. The snowpack loss also leads to significant changes in runoff timing, which are also inevitable.

  5. Soil moisture datasets at five sites in the central Sierra Nevada and northern Coast Ranges, California

    Science.gov (United States)

    Stern, Michelle A.; Anderson, Frank A.; Flint, Lorraine E.; Flint, Alan L.

    2018-05-03

    In situ soil moisture datasets are important inputs used to calibrate and validate watershed, regional, or statewide modeled and satellite-based soil moisture estimates. The soil moisture dataset presented in this report includes hourly time series of the following: soil temperature, volumetric water content, water potential, and total soil water content. Data were collected by the U.S. Geological Survey at five locations in California: three sites in the central Sierra Nevada and two sites in the northern Coast Ranges. This report provides a description of each of the study areas, procedures and equipment used, processing steps, and time series data from each site in the form of comma-separated values (.csv) tables.

  6. Detecting Drought-Induced Tree Mortality in Sierra Nevada Forests with Time Series of Satellite Data

    Directory of Open Access Journals (Sweden)

    Sarah Byer

    2017-09-01

    Full Text Available A five-year drought in California led to a significant increase in tree mortality in the Sierra Nevada forests from 2012 to 2016. Landscape level monitoring of forest health and tree dieback is critical for vegetation and disaster management strategies. We examined the capability of multispectral imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS in detecting and explaining the impacts of the recent severe drought in Sierra Nevada forests. Remote sensing metrics were developed to represent baseline forest health conditions and drought stress using time series of MODIS vegetation indices (VIs and a water index. We used Random Forest algorithms, trained with forest aerial detection surveys data, to detect tree mortality based on the remote sensing metrics and topographical variables. Map estimates of tree mortality demonstrated that our two-stage Random Forest models were capable of detecting the spatial patterns and severity of tree mortality, with an overall producer’s accuracy of 96.3% for the classification Random Forest (CRF and a RMSE of 7.19 dead trees per acre for the regression Random Forest (RRF. The overall omission errors of the CRF ranged from 19% for the severe mortality class to 27% for the low mortality class. Interpretations of the models revealed that forests with higher productivity preceding the onset of drought were more vulnerable to drought stress and, consequently, more likely to experience tree mortality. This method highlights the importance of incorporating baseline forest health data and measurements of drought stress in understanding forest response to severe drought.

  7. Onset and Multiple Fluctuations of Holocene Glaciation in the Sierra Nevada, California

    Science.gov (United States)

    Bowerman, N. D.; Clark, D. H.

    2004-12-01

    Multiple sediment cores from two paternoster tarns (First and Second lakes) in North Fork Big Pine Creek, Sierra Nevada, preserve the most detailed and complete record of Holocene glaciation yet recovered in the range; they indicate that the glacier was absent during the early Holocene, reformed in the late Holocene, and experienced several expansions and contractions, culminating with the Matthes maximum during the last ˜200 years. The lakes are fed by outwash from the Palisade Glacier, the largest ( ˜1.3 km2) and presumably longest-lived glacier in the Sierra Nevada, and capture essentially all of the rock flour produced by the glacier. Distinct late-Holocene (Matthes) and late-Pleistocene (Recess Peak) moraines lie between the modern glacier and the lakes. Thus, the lakes have received continuous sedimentation since the retreat of the Tioga glacier ( ˜15,000 yr B.P.), and therefore capture rock flour related to all subsequent advances. First and Second lakes occupy relatively deep bedrock basins at 3036 m and 3066 m asl., respectively. Third Lake, a shallow (rock flour (outwash) from the upstream Palisade Glacier, most likely related to formation and expansions of the glacier in the late Holocene. The maximum peak at the top of the cores confirms the moraine record, which indicates that the maximum Holocene advance of Sierran glaciers occurred during the late Little Ice Age (last ˜200 yr) At least one tephra layer, possibly related to the Mono/Inyo dome complexes, occurs in the middle depths of the First Lake cores. Other narrow peaks in MS may also be associated with tephra deposits. Ongoing detailed analyses of the sediments, including AMS radiocarbon dating, visual and x-ray imaging, particle size analysis, organic content, tephrochronology, diatom assemblages, and palynology will constrain the timing and character of the environmental fluctuations related to the rock-flour flux. We will present results of these analyses at the meeting.

  8. A quantitative evaluation of the conservation umbrella of spotted owl management areas in the Sierra Nevada.

    Directory of Open Access Journals (Sweden)

    Ryan D Burnett

    Full Text Available Whether by design or default, single species management often serves as an umbrella for species with similar habitat requirements. In recent decades the focus of National Forest management in the Sierra Nevada of California has shifted towards increasing closed canopy mature forest conditions through the protection of areas occupied by the California Spotted Owl (Strix occidentalis occidentalis. To evaluate the implications of these habitat changes and the potential umbrella resulting from a system of owl reserves on the broader avian community, we estimated occupancy of birds inside and outside of Spotted Owl Home Range Core Areas in northeastern California. We used point count data in a multi-species hierarchical Bayesian model incorporating the detection history of 81 species over a two-year time period (2005-2006. A small set of vegetation cover and topography covariates were included in the model to account for broad differences in habitat conditions, as well as a term identifying whether or not a site was within a Core Area. Seventeen species had a negative Core Area effect, seven had a positive effect, and the rest were not significant. Estimated species richness was significantly different with 23.1 species per 100 m radius circle outside Core Areas and 21.7 inside Core Areas. The majority of the species negatively associated with Core Areas are tied to early successional and other disturbance-dependent habitats. Conservation and climate vulnerability rankings were mixed. On average we found higher scores (greater risk for the species positively associated with Core Areas, but a larger number of species with the highest scores were negatively associated with Core Areas. We discuss the implications for managing the Sierra Nevada ecosystem and illustrate the role of monitoring broader suites of species in guiding management of large complex ecosystems.

  9. Principal Hydrologic Responses to Climatic and Geologic Variability in the Sierra Nevada, California

    Directory of Open Access Journals (Sweden)

    David H. Peterson

    2008-02-01

    Full Text Available Sierra Nevada snowpack is a critical water source for California’s growing population and agricultural industry. However, because mountain winters and springs are warming, on average, precipitation as snowfall relative to rain is decreasing, and snowmelt is earlier. The changes are stronger at mid-elevations than at higher elevations. The result is that the water supply provided by snowpack is diminishing. In this paper, we describe principal hydrologic responses to climatic and spatial geologic variations as gleaned from a series of observations including snowpack, stream-flow, and bedrock geology. Our analysis focused on peak (maximum and base (minimum daily discharge of the annual snowmelt-driven hydrographs from 18 Sierra Nevada watersheds and 24 stream gage locations using standard correlation methods. Insights into the importance of the relative magnitudes of peak flow and soil water storage led us to develop a hydrologic classification of mountain watersheds based on runoff versus base flow as a percentage of peak flow. Our findings suggest that watersheds with a stronger base flow response store more soil water than watersheds with a stronger peak-flow response. Further, the influence of antecedent wet or dry years is greater in watersheds with high base flow, measured as a percentage of peak flow. The strong correlation between 1 the magnitude of peak flow, and 2 snow water equivalent can be used to predict peak flow weeks in advance. A weaker but similar correlation can be used to predict the magnitude of base flow months in advance. Most of the watersheds show a trend that peak flow is occurring earlier in the year.

  10. Partitioning of water flux in a Sierra Nevada ponderosa pine plantation

    Science.gov (United States)

    Kurpius, M.R.; Panek, J.A.; Nikolov, N.T.; McKay, M.; Goldstein, Allen H.

    2003-01-01

    The weather patterns of the west side of the Sierra Nevada Mountains (cold, wet winters and hot, dry summers) strongly influence how water is partitioned between transpiration and evaporation and result in a specific strategy of water use by ponderosa pine trees (Pinus ponderosa) in this region. To investigate how year-round water fluxes were partitioned in a young ponderosa pine ecosystem in the Sierra Nevada Mountains, water fluxes were continually measured from June 2000 to May 2001 using a combination of sap flow and eddy covariance techniques (above- and below-canopy). Water fluxes were modeled at our study site using a biophysical model, FORFLUX. During summer and fall water fluxes were equally partitioned between transpiration and soil evaporation while transpiration dominated the water fluxes in winter and spring. The trees had high rates of canopy conductance and transpiration in the early morning and mid-late afternoon and a mid-day depression during the dry season. We used a diurnal centroid analysis to show that the timing of high canopy conductance and transpiration relative to high vapor pressure deficit (D) shifted with soil moisture: during periods of low soil moisture canopy conductance and transpiration peaked early in the day when D was low. Conversely, during periods of high soil moisture canopy conductance and transpiration peaked at the same time or later in the day than D. Our observations suggest a general strategy by the pine trees in which they maximize stomatal conductance, and therefore carbon fixation, throughout the day on warm sunny days with high soil moisture (i.e. warm periods in winter and late spring) and maximize stomatal conductance and carbon fixation in the morning through the dry periods. FORFLUX model estimates of evaporation and transpiration were close to measured/calculated values during the dry period, including the drought, but underestimated transpiration and overestimated evaporation during the wet period. ?? 2003

  11. A Geochemical Comparison of the Northern Peninsular Ranges Batholith in Southern California and the Coastal Batholith in Southern Peru

    Science.gov (United States)

    Clausen, B. L.; Martínez Ardila, A. M.; Morton, D. M.

    2010-12-01

    , tonalite, monzonite, and granodiorite. In addition, samples were taken from the adjacent Precambrian basement and Paleozoic San Nicolas batholith in order to estimate the local geochemistry for continental crust contamination and to compare with published crustal averages. For this part of the Coastal Batholith, gabbroic plutons that formed during extension have little contamination from continental crust; the time-separated super-units form distinct assemblages; some of the super-units went through several differentiation cycles; parts of the Linga super-unit have low Sri ratios below 0.704; and magma mixing played an important role. The Coastal Batholith of western Peru (similar to the eastern PRB) has an intermediate calc-alkaline composition, in comparison to batholiths in Chile (similar to the western PRB) that are more calcic and those in eastern Peru (similar to the Sierra Nevadas) that are more alkaline.

  12. Modeling Multi-Reservoir Hydropower Systems in the Sierra Nevada with Environmental Requirements and Climate Warming

    Science.gov (United States)

    Rheinheimer, David Emmanuel

    Hydropower systems and other river regulation often harm instream ecosystems, partly by altering the natural flow and temperature regimes that ecosystems have historically depended on. These effects are compounded at regional scales. As hydropower and ecosystems are increasingly valued globally due to growing values for clean energy and native species as well as and new threats from climate warming, it is important to understand how climate warming might affect these systems, to identify tradeoffs between different water uses for different climate conditions, and to identify promising water management solutions. This research uses traditional simulation and optimization to explore these issues in California's upper west slope Sierra Nevada mountains. The Sierra Nevada provides most of the water for California's vast water supply system, supporting high-elevation hydropower generation, ecosystems, recreation, and some local municipal and agricultural water supply along the way. However, regional climate warming is expected to reduce snowmelt and shift runoff to earlier in the year, affecting all water uses. This dissertation begins by reviewing important literature related to the broader motivations of this study, including river regulation, freshwater conservation, and climate change. It then describes three substantial studies. First, a weekly time step water resources management model spanning the Feather River watershed in the north to the Kern River watershed in the south is developed. The model, which uses the Water Evaluation And Planning System (WEAP), includes reservoirs, run-of-river hydropower, variable head hydropower, water supply demand, and instream flow requirements. The model is applied with a runoff dataset that considers regional air temperature increases of 0, 2, 4 and 6 °C to represent historical, near-term, mid-term and far-term (end-of-century) warming. Most major hydropower turbine flows are simulated well. Reservoir storage is also

  13. Effects of Climate and Fuels Management on Wildfire Occurrence, Size, Severity and Emissions in the Sierra Nevada

    Science.gov (United States)

    Westerling, A. L.; Fites, J. A.; Keyser, A.

    2015-12-01

    Annual wildfire burned area in federally managed Sierra Nevada forests has increased by more than 10,000 ha per decade since the early 1970s. At the same time, recent years have seen some extremely large fires compared to the historical record, with significant areas of moderate to high severity fire (e.g., McNally 2002, Rim 2013, King 2014 fires). Changes to fuels and fire regimes due to fire suppression and land use, as well as warming temperatures and the occurrence of drought, are thought to be significant factors contributing to increased risks of large, severe fires in Sierra Nevada forests. Over 70% of the vegetated area in federally managed forests in the Sierra Nevada is classified as having altered fuels and fire regimes, while average annual temperature in the Sierra Nevada has been above the long term mean for all but four years in the past two decades. As climate is expected to continue warming for decades to come, we explored fuels management scenarios as the primary tools available to modify risks of large, severe wildfires. We developed experimental statistical models of fire occurrence, fire size, and high severity burned area, to explore the interaction between climate and altered fuels conditions. These models were applied to historical climate conditions, a sample of future climate projections, and to both current fuels conditions and a range of scenarios for fuels treatments. Emissions from wildfires were estimated using the Fire Inventory from the National Center for Atmospheric Research. Our models project that average annual burned area in the Sierra Nevada will more than double by mid-century. Similarly, particulate and other pollution emissions from Sierra Nevada wildfires are projected to more than double, even if future fire severity does not change. Fuels treatment scenarios significantly reduced simulated future burned area and emissions below untreated projections. High severity burned area responded to both climate and fuels

  14. Measured Black Carbon Deposition on the Sierra Nevada Snow Pack and Implication for Snow Pack Retreat

    Energy Technology Data Exchange (ETDEWEB)

    Hadley, O.L.; Corrigan, C.E.; Kirchstetter, T.W.; Cliff, S.S.; Ramanathan, V.

    2010-01-12

    Modeling studies show that the darkening of snow and ice by black carbon deposition is a major factor for the rapid disappearance of arctic sea ice, mountain glaciers and snow packs. This study provides one of the first direct measurements for the efficient removal of black carbon from the atmosphere by snow and its subsequent deposition to the snow packs of California. The early melting of the snow packs in the Sierras is one of the contributing factors to the severe water problems in California. BC concentrations in falling snow were measured at two mountain locations and in rain at a coastal site. All three stations reveal large BC concentrations in precipitation, ranging from 1.7 ng/g to 12.9 ng/g. The BC concentrations in the air after the snow fall were negligible suggesting an extremely efficient removal of BC by snow. The data suggest that below cloud scavenging, rather than ice nuclei, was the dominant source of BC in the snow. A five-year comparison of BC, dust, and total fine aerosol mass concentrations at multiple sites reveals that the measurements made at the sampling sites were representative of large scale deposition in the Sierra Nevada. The relative concentration of iron and calcium in the mountain aerosol indicates that one-quarter to one-third of the BC may have been transported from Asia.

  15. Status and understanding of groundwater quality in the Sierra Nevada Regional study unit, 2008: California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2014-01-01

    Groundwater quality in the Sierra Nevada Regional (SNR) study unit was investigated as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment Program Priority Basin Project. The study was designed to provide statistically unbiased assessments of the quality of untreated groundwater within the primary aquifer system of the Sierra Nevada. The primary aquifer system for the SNR study unit was delineated by the depth intervals over which wells in the State of California’s database of public drinking-water supply wells are open or screened. Two types of assessments were made: (1) a status assessment that described the current quality of the groundwater resource, and (2) an evaluation of relations between groundwater quality and potential explanatory factors that represent characteristics of the primary aquifer system. The assessments characterize untreated groundwater quality, rather than the quality of treated drinking water delivered to consumers by water distributors.

  16. Evaluating the Spatial Distribution of Toxic Air Contaminants in Multiple Ecosystem Indicators in the Sierra Nevada-Southern Cascades

    Science.gov (United States)

    Nanus, L.; Simonich, S. L.; Rocchio, J.; Flanagan, C.

    2013-12-01

    Toxic air contaminants originating from agricultural areas of the Central Valley in California threaten vulnerable sensitive receptors including surface water, vegetation, snow, sediments, fish, and amphibians in the Sierra Nevada-Southern Cascades region. The spatial distribution of toxic air contaminants in different ecosystem indicators depends on variation in atmospheric concentrations and deposition, and variation in air toxics accumulation in ecosystems. The spatial distribution of organic air toxics and mercury at over 330 unique sampling locations and sample types over two decades (1990-2009) in the Sierra Nevada-Southern Cascades region were compiled and maps were developed to further understand spatial patterns and linkages between air toxics deposition and ecological effects. Potential ecosystem impacts in the Sierra Nevada-Southern Cascades region include bioaccumulation of air toxics in both aquatic and terrestrial ecosystems, reproductive disruption, and immune suppression. The most sensitive ecological end points in the region that are affected by bioaccumulation of toxic air contaminants are fish. Mercury was detected in all fish and approximately 6% exceeded human consumption thresholds. Organic air toxics were also detected in fish yielding variable spatial patterns. For amphibians, which are sensitive to pesticide exposure and potential immune suppression, increasing trends in current and historic use pesticides are observed from north to south across the region. In other indicators, such as vegetation, pesticide concentrations in lichen increase with increasing elevation. Current and historic use pesticides and mercury were also observed in snowpack at high elevations in the study area. This study shows spatial patterns in toxic air contaminants, evaluates associated risks to sensitive receptors, and identifies data gaps. Future research on atmospheric modeling and information on sources is needed in order to predict which ecosystems are the

  17. Effect of Tree-to-Shrub Type Conversion in Lower Montane Forests of the Sierra Nevada (USA) on Streamflow.

    Science.gov (United States)

    Bart, Ryan R; Tague, Christina L; Moritz, Max A

    2016-01-01

    Higher global temperatures and increased levels of disturbance are contributing to greater tree mortality in many forest ecosystems. These same drivers can also limit forest regeneration, leading to vegetation type conversion. For the Sierra Nevada of California, little is known about how type conversion may affect streamflow, a critical source of water supply for urban, agriculture and environmental purposes. In this paper, we examined the effects of tree-to-shrub type conversion, in combination with climate change, on streamflow in two lower montane forest watersheds in the Sierra Nevada. A spatially distributed ecohydrologic model was used to simulate changes in streamflow, evaporation, and transpiration following type conversion, with an explicit focus on the role of vegetation size and aspect. Model results indicated that streamflow may show negligible change or small decreases following type conversion when the difference between tree and shrub leaf areas is small, partly due to the higher stomatal conductivity and the deep rooting depth of shrubs. In contrast, streamflow may increase when post-conversion shrubs have a small leaf area relative to trees. Model estimates also suggested that vegetation change could have a greater impact on streamflow magnitude than the direct hydrologic impacts of increased temperatures. Temperature increases, however, may have a greater impact on streamflow timing. Tree-to-shrub type conversion increased streamflow only marginally during dry years (annual precipitation importance of accounting for changes in vegetation communities to accurately characterize future hydrologic regimes for the Sierra Nevada.

  18. Anthropogenic Warming Impacts on Today's Sierra Nevada Snowpack and Flood Severity

    Science.gov (United States)

    Huang, X.; Hall, A. D.; Berg, N.

    2017-12-01

    Focusing on this recent extreme wet year over California, this study investigates the warming impacts on the snowpack and the flood severity over the Sierra Nevada (SN), where the majority of the precipitation occurs during the winter season and early spring. One of our goals is to quantify anthropogenic warming impacts on the snow water equivalent (SWE) including recent historical warming and prescribed future projected warming scenarios; This work also explores to what extent flooding risk has increased under those warming cases. With a good representation of the historical precipitation and snowpack over the Sierra Nevada from the historical reference run at 9km (using WRF), the results from the offline Noah-MP simulations with perturbed near-surface temperatures reveal magnificent impacts of warming to the loss of the average snowpack. The reduction of the SWE under warming mainly results from the decreased rain-to-snow conversion with a weaker effect from increased snowmelt. Compared to the natural case, the past industrial warming decreased the maximum SWE by about one-fifth averaged over the study area. Future continuing warming can result in around one-third reduction of current maximum SWE under RCP4.5 emissions scenario, and the loss can reach to two-thirds under RCP8.5 as a "business-as-usual" condition. The impact of past warming is particularly outstanding over the North SN region where precipitation dominates and over the middle elevation regions where the snow mainly distributes. In the future, the warming impact on SWE progresses to higher regions, and so to the south and east. Under the business-as-usual scenario, the projected mid-elevation snowpack almost disappears by April 1st with even high-elevation snow reduced by about half. Along with the loss of the snowpack, as the temperature warms, floods can also intensify with increased early season runoff especially under heavy-rainy days caused by the weakened rain-to-snow processes and

  19. Observations of the diurnal and seasonal trends in nitrogen oxides in the western Sierra Nevada

    Directory of Open Access Journals (Sweden)

    J. G. Murphy

    2006-01-01

    Full Text Available Observations of speciated nitrogen oxides, namely NO2, total peroxy nitrates (ΣPNs, total alkyl nitrates (ΣANs, and HNO3 by thermal dissociation laser induced fluorescence (TD-LIF, and supporting chemical and meteorological measurements at Big Hill (1860 m, a high elevation site in California's Sierra Nevada Mountains, are described. From May through October, terrain-driven winds in the region routinely bring air from Sacramento, 100 km southwest of the site, upslope over oak and pine forests to Big Hill during the day, while at night, the site often samples clean, dry air characteristic of the free troposphere. Winter differs mainly in that the meteorology does not favour the buildup of Sacramento's pollution over the Sierra Nevada range, and the urban-influenced air that is seen has been less affected by biogenic VOC emissions, resulting in longer lifetime for NO2 and a predominance of the inorganic forms of nitrogen oxides. Summertime observations at Big Hill can be compared with those from Granite Bay, a Sacramento suburb, and from the University of California's Blodgett Forest Research Station to examine the evolution of nitrogen oxides and ozone within the urban plume. Nitrogen oxide radicals (NO and NO2, which dominate total nitrogen oxides (NOy at Granite Bay, are rapidly converted into HNO3, ΣPNs, and ΣANs, such that these compounds contribute 29, 30, and 21% respectively to the NOy budget in the plume at Big Hill. Nevertheless, the decreasing concentrations of NO2 as the plume is advected to Big Hill lead to decreases in the production rate of HNO3 and ozone. The data also demonstrate the role that temperature plays in sequestering NO2 into peroxy nitrates, effectively decreasing the rate of ozone production. The important contribution of ΣANs to NOy in the region suggests that they should be considered with regards to export of NOy from the boundary layer. Nocturnal observations of airmasses characteristic of the

  20. Wireless sensor networks to assess the impacts of global change in Sierra Nevada (Spain) mountains

    Science.gov (United States)

    Sánchez-Cano, Francisco M.; Bonet-García, Francisco J.; Pérez-Luque, Antonio J.; Suárez-Muñoz, María

    2017-04-01

    Sierra Nevada Global Change Observatory (southern Spain) aims to improve the ability of ecosystems to address the impacts of global change. To this end, a monitoring program has been implemented based on the collection of long time series on a multitude of biophysical variables. This initiative is part of the Long Term Ecological Research network and is connected to similar ones at national and international level. One of the specific objectives of this LTER site is to improve understanding of the relationships between abiotic factors and ecosystem functioning / structure. Wireless sensor networks are a key instrument for achieving this aim. This contribution describes the design and management of a sensor network that is intended to monitor several biophysical variables with high temporal and spatial resolution in Quercus pyrenaica forests located in this mountain region. The following solution has been adopted in order to obtain the observational data (physical and biological variables). The biological variables will be monitored by PAR sensors (photosynthetically active radiation), and the physical variables will be acquired by a meteorological station and a sensor network composed of temperature and soil moisture sensors, as well as air temperature and humidity ones. To complete the monitoring of the biological variables, a NDVI (Normalized Difference Vegetation Index) camera will be deployed focusing to a Quercus pyrenaica forest from the opposite slope. It should be noted that all monitoring systems exposed will be powered by solar energy. The management of the sensor network covers the deployment of more than 100 sensors, guaranteeing both remote accessibility and reliability of the data. The chosen solution is provided by the company Adevice whose ONE-GO communication system ensures a consistent and efficient sending of those values read by the different sensors towards a central point, from where the information (RAW data) is accessible through WiFi/3G

  1. Mediterranean climate effects. II. Conifer growth phenology across a Sierra Nevada ecotone.

    Science.gov (United States)

    Royce, E B; Barbour, M G

    2001-05-01

    Growth and xylem water potential of the lower elevation conifers Pinus jeffreyi and Abies concolor and the higher elevation Pinus monticola and Abies magnifica were monitored in their montane Mediterranean habitat of the southernmost Sierra Nevada mountains of California. Measurements were made across the ecotone between the midmontane and upper montane forests and through light and heavy snowfall years.Radial stem growth, averaging ∼1.5 mm/yr, started 2 wk after snow melt, providing that maximum air temperatures had reached 21°C, and ended when predawn water potentials fell rapidly at the onset of the summer drought. Leader growth started on or after a fixed date, providing that minimum air temperatures were above -4°C for Pinus species or +2.5°C for Abies species. The cue for leader growth was inferred to be photoperiodic. Leader growth ended when either a determinate internode length of ∼1 mm was reached or predawn water potentials fell rapidly. Abies magnifica grew more rapidly than the low-elevation species, but had a shorter growth period; its annual leader growth, as a consequence, was only 35 mm/yr vs. 50 mm/yr for the low-elevation species. Needle growth was similarly determinate in the absence of early drought. This growth phenology contributes to determining species distribution across the ecotone.

  2. Long Valley caldera and the UCERF depiction of Sierra Nevada range-front faults

    Science.gov (United States)

    Hill, David P.; Montgomery-Brown, Emily K.

    2015-01-01

    Long Valley caldera lies within a left-stepping offset in the north-northwest-striking Sierra Nevada range-front normal faults with the Hilton Creek fault to the south and Hartley Springs fault to the north. Both Uniform California Earthquake Rupture Forecast (UCERF) 2 and its update, UCERF3, depict slip on these major range-front normal faults as extending well into the caldera, with significant normal slip on overlapping, subparallel segments separated by ∼10  km. This depiction is countered by (1) geologic evidence that normal faulting within the caldera consists of a series of graben structures associated with postcaldera magmatism (intrusion and tumescence) and not systematic down-to-the-east displacements consistent with distributed range-front faulting and (2) the lack of kinematic evidence for an evolving, postcaldera relay ramp structure between overlapping strands of the two range-front normal faults. The modifications to the UCERF depiction described here reduce the predicted shaking intensity within the caldera, and they are in accord with the tectonic influence that underlapped offset range-front faults have on seismicity patterns within the caldera associated with ongoing volcanic unrest.

  3. [Dung beetles (Coleoptera: Scarabaeinae) of the northwestern slope of the Sierra Nevada of Santa Marta, Colombia].

    Science.gov (United States)

    Martínez, Neis J; García, Héctor; Pulido, Luz A; Ospino, Deibi; Harváez, Juan C

    2009-01-01

    The community structure of dung beetles in the middle and lower river basin of the Gaira river, Sierra Nevada de Santa Marta, Colombia, is described. Four sites were selected along an altitudinal gradient of 50-940 m for sampling from June to October, 2004. Dung beetles were captured using modified pitfall traps and manual recollections. We captured 7,872 individuals belonging to 29 species, distributed in 15 genera and five tribes of Scarabaeinae. Canthon and Onthophagus were the most diverse genera, each represented by six species. The sampled sites shared the following species: Onthophagus acuminatus Harold, O. clypeatus Blanchard, O. marginicollis Harold. Bocatoma was the most diverse site with 23 species; whereas Port Mosquito presented the highest abundance, with 3,262 individuals. Seven species represented 89% of all captures: Canthidium sp., Dichotomius sp., Uroxys sp. 1, Uroxys sp. 2, O. marginicollis, O. clypeatus and O. acuminatus. Of the 29 captured species, 17 belonged to the functional group of diggers and 10 were ball-rollers. We did not observe significant among-site differences in community structure. Abiotic factors such as altitude, temperature and humidity cannot explain observed variation in community structure across sites, indicating other variables such as vegetation cover, density of the vegetation and soil type may play a role in the community structure of these insects.

  4. Can footwall unloading explain late Cenozoic uplift of the Sierra Nevada crest?

    Science.gov (United States)

    Thompson, G.A.; Parsons, T.

    2009-01-01

    Globally, normal-fault displacement bends and warps rift flanks upwards, as adjoining basins drop downwards. Perhaps the most evident manifestations are the flanks of the East African Rift, which cuts across the otherwise minimally deformed continent. Flank uplift was explained by Vening Meinesz (1950, Institut Royal Colonial Belge, Bulletin des Seances, v. 21, p. 539-552), who recognized that isostasy should cause uplift of a normal-faulted footwall and subsidence of its hanging wall. Uplift occurs because slip on a dipping normal fault creates a broader root of less-dense material beneath the footwall, and a narrowed one beneath the hanging wall. In this paper, we investigate the potential influence of this process on the latest stages of Sierra Nevada uplift. Through theoretical calculations and 3D finite element modelling, we find that cumulative slip of about 4km on range-front faults would have produced about 1.3km peak isostatic uplift at the ridge crest. Numerical models suggest that the zone of uplift is narrow, with the width controlled by bending resistance of the seismogenic crust. We conclude that footwall unloading cannot account for the entire elevation of the Sierran crest above sea level, but if range-front faulting initiated in an already elevated plateau like the adjacent Basin and Range Province, then a hybrid model of pre-existing regional uplift and localized footwall unloading can account for the older and newer uplift phases suggested by the geologic record.

  5. Air Pollution and Watershed Research in the Central Sierra Nevada of California: Nitrogen and Ozone

    Directory of Open Access Journals (Sweden)

    Carolyn Hunsaker

    2007-01-01

    Full Text Available Maintaining healthy forests is the major objective for the Forest Service scientists and managers working for the U.S. Department of Agriculture. Air pollution, specifically ozone (O3 and nitrogenous (N air pollutants, may severely affect the health of forest ecosystems in the western U.S. Thus, the monitoring of air pollution concentration and deposition levels, as well as studies focused on understanding effects mechanisms, are essential for evaluation of risks associated with their presence. Such information is essential for development of proper management strategies for maintaining clean air, clean water, and healthy ecosystems on land managed by the Forest Service. We report on two years of research in the central Sierra Nevada of California, a semi-arid forest at elevations of 1100–2700 m. Information on O3 and N air pollutants is obtained from a network of 18 passive samplers. We relate the atmospheric N concentration to N concentrations in streams, shallow soil water, and bulk deposition collectors within the Kings River Experimental Watershed. This watershed also contains an intensive site that is part of a recent Forest Service effort to calculate critical loads for N, sulfur, and acidity to forest ecosystems. The passive sampler design allows for extensive spatial measurements while the watershed experiment provides intensive spatial data for future analysis of ecosystem processes.

  6. Characterizing the Networks of Digital Information that Support Collaborative Adaptive Forest Management in Sierra Nevada Forests

    Science.gov (United States)

    Lei, Shufei; Iles, Alastair; Kelly, Maggi

    2015-07-01

    Some of the factors that can contribute to the success of collaborative adaptive management—such as social learning, open communication, and trust—are built upon a foundation of the open exchange of information about science and management between participants and the public. Despite the importance of information transparency, the use and flow of information in collaborative adaptive management has not been characterized in detail in the literature, and currently there exist opportunities to develop strategies for increasing the exchange of information, as well as to track information flow in such contexts. As digital information channels and networks have been increased over the last decade, powerful new information monitoring tools have also been evolved allowing for the complete characterization of information products through their production, transport, use, and monitoring. This study uses these tools to investigate the use of various science and management information products in a case study—the Sierra Nevada Adaptive Management Project—using a mixed method (citation analysis, web analytics, and content analysis) research approach borrowed from the information processing and management field. The results from our case study show that information technologies greatly facilitate the flow and use of digital information, leading to multiparty collaborations such as knowledge transfer and public participation in science research. We conclude with recommendations for expanding information exchange in collaborative adaptive management by taking advantage of available information technologies and networks.

  7. Leaf Area Prediction Using Three Alternative Sampling Methods for Seven Sierra Nevada Conifer Species

    Directory of Open Access Journals (Sweden)

    Dryw A. Jones

    2015-07-01

    Full Text Available Prediction of projected tree leaf area using allometric relationships with sapwood cross-sectional area is common in tree- and stand-level production studies. Measuring sapwood is difficult and often requires destructive sampling. This study tested multiple leaf area prediction models across seven diverse conifer species in the Sierra Nevada of California. The best-fit whole tree leaf area prediction model for overall simplicity, accuracy, and utility for all seven species was a nonlinear model with basal area as the primary covariate. A new non-destructive procedure was introduced to extend the branch summation approach to leaf area data collection on trees that cannot be destructively sampled. There were no significant differences between fixed effects assigned to sampling procedures, indicating that data from the tested sampling procedures can be combined for whole tree leaf area modeling purposes. These results indicate that, for the species sampled, accurate leaf area estimates can be obtained through partially-destructive sampling and using common forest inventory data.

  8. Ten Years of Forest Cover Change in the Sierra Nevada Detected Using Landsat Satellite Image Analysis

    Science.gov (United States)

    Potter, Christopher S.

    2014-01-01

    The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology was applied to detected changes in forest vegetation cover for areas burned by wildfires in the Sierra Nevada Mountains of California between the periods of 1975- 79 and 1995-1999. Results for areas burned by wildfire between 1995 and 1999 confirmed the importance of regrowing forest vegetation over 17% of the combined burned areas. A notable fraction (12%) of the entire 5-km (unburned) buffer area outside the 1995-199 fires perimeters showed decline in forest cover, and not nearly as many regrowing forest areas, covering only 3% of all the 1995-1999 buffer areas combined. Areas burned by wildfire between 1975 and 1979 confirmed the importance of disturbed (or declining evergreen) vegetation covering 13% of the combined 1975- 1979 burned areas. Based on comparison of these results to ground-based survey data, the LEDAPS methodology should be capable of fulfilling much of the need for consistent, low-cost monitoring of changes due to climate and biological factors in western forest regrowth following stand-replacing disturbances.

  9. Characterizing the Networks of Digital Information that Support Collaborative Adaptive Forest Management in Sierra Nevada Forests.

    Science.gov (United States)

    Lei, Shufei; Iles, Alastair; Kelly, Maggi

    2015-07-01

    Some of the factors that can contribute to the success of collaborative adaptive management--such as social learning, open communication, and trust--are built upon a foundation of the open exchange of information about science and management between participants and the public. Despite the importance of information transparency, the use and flow of information in collaborative adaptive management has not been characterized in detail in the literature, and currently there exist opportunities to develop strategies for increasing the exchange of information, as well as to track information flow in such contexts. As digital information channels and networks have been increased over the last decade, powerful new information monitoring tools have also been evolved allowing for the complete characterization of information products through their production, transport, use, and monitoring. This study uses these tools to investigate the use of various science and management information products in a case study--the Sierra Nevada Adaptive Management Project--using a mixed method (citation analysis, web analytics, and content analysis) research approach borrowed from the information processing and management field. The results from our case study show that information technologies greatly facilitate the flow and use of digital information, leading to multiparty collaborations such as knowledge transfer and public participation in science research. We conclude with recommendations for expanding information exchange in collaborative adaptive management by taking advantage of available information technologies and networks.

  10. Retention and radiative forcing of black carbon in eastern Sierra Nevada snow

    Directory of Open Access Journals (Sweden)

    K. M. Sterle

    2013-02-01

    Full Text Available When contaminated by absorbing particles, such as refractory black carbon (rBC and continental dust, snow's albedo decreases and thus its absorption of solar radiation increases, thereby hastening snowmelt. For this reason, an understanding of rBC's affect on snow albedo, melt processes, and radiation balance is critical for water management, especially in a changing climate. Measurements of rBC in a sequence of snow pits and surface snow samples in the eastern Sierra Nevada of California during the snow accumulation and ablation seasons of 2009 show that concentrations of rBC were enhanced sevenfold in surface snow (~25 ng g–1 compared to bulk values in the snowpack (~3 ng g–1. Unlike major ions, which were preferentially released during the initial melt, rBC and continental dust were retained in the snow, enhancing concentrations well into late spring, until a final flush occurred during the ablation period. We estimate a combined rBC and continental dust surface radiative forcing of 20 to 40 W m−2 during April and May, with dust likely contributing a greater share of the forcing.

  11. Evaluating potential overlap between pack stock and Sierra Nevada bighorn sheep (Ovis canadensis sierrae) in Sequoia and Kings Canyon National Parks, California

    Science.gov (United States)

    Klinger, Robert C.; Few, Alexandra P.; Knox, Kathleen A.; Hatfield, Brian E.; Clark, Jonathan; German, David W.; Stephenson, Thomas R.

    2015-01-01

    Pack stock (horses, mules, burros, llamas, and goats) are frequently assumed to have negative effects on public lands, but there is a general lack of data to be able to quantify the degree to which this is actually the case. Sequoia and Kings Canyon National Parks have received complaints that pack stock may affect Sierra Nevada bighorn sheep (Ovis canadensis sierrae; SNBS), a federally endangered subspecies that occurs in largely disjunct herds in the Sierra Nevada Range of California. The potential effects are thought to be displacement of SNBS from meadows on their summer range (altered habitat use) or, more indirectly, through changes in SNBS habitat or forage quality. Our goals were to conduct an association analysis to quantify the degree of potential spatial overlap in meadow use between SNBS and pack stock and to compare differences in vegetation community composition, structure, and diversity among meadows with different levels of use by bighorn sheep and pack stock. For the association analysis, we used two approaches: (1) we quantified the proportion of meadows that were within the herd home ranges of bighorn sheep and were potentially open to pack stock, and, (2) we used Monte Carlo simulations and use-availability analyses to compare the proportion of meadows used by bighorn sheep relative to the proportional occurrence or area of meadows available to bighorn sheep that were used by pack stock. To evaluate potential effects of pack stock on meadow plant communities and SNBS forage, we sampled vegetation in 2011 and 2012 at 100 plots to generate data that allowed us to compare:

  12. Simulating 3-D radiative transfer effects over the Sierra Nevada Mountains using WRF

    Directory of Open Access Journals (Sweden)

    Y. Gu

    2012-10-01

    Full Text Available A surface solar radiation parameterization based on deviations between 3-D and conventional plane-parallel radiative transfer models has been incorporated into the Weather Research and Forecasting (WRF model to understand the solar insolation over mountain/snow areas and to investigate the impact of the spatial and temporal distribution and variation of surface solar fluxes on land-surface processes. Using the Sierra-Nevada in the western United States as a testbed, we show that mountain effect could produce up to −50 to + 50 W m−2 deviations in the surface solar fluxes over the mountain areas, resulting in a temperature increase of up to 1 °C on the sunny side. Upward surface sensible and latent heat fluxes are modulated accordingly to compensate for the change in surface solar fluxes. Snow water equivalent and surface albedo both show decreases on the sunny side of the mountains, indicating more snowmelt and hence reduced snow albedo associated with more solar insolation due to mountain effect. Soil moisture increases on the sunny side of the mountains due to enhanced snowmelt, while decreases on the shaded side. Substantial differences are found in the morning hours from 8–10 a.m. and in the afternoon around 3–5 p.m., while differences around noon and in the early morning and late afternoon are comparatively smaller. Variation in the surface energy balance can also affect atmospheric processes, such as cloud fields, through the modulation of vertical thermal structure. Negative changes of up to −40 g m−2 are found in the cloud water path, associated with reductions in the surface insolation over the cloud region. The day-averaged deviations in the surface solar flux are positive over the mountain areas and negative in the valleys, with a range between −12~12 W m−2. Changes in sensible and latent heat fluxes and surface skin temperature follow the solar insolation pattern. Differences in the

  13. Effect of Tree-to-Shrub Type Conversion in Lower Montane Forests of the Sierra Nevada (USA on Streamflow.

    Directory of Open Access Journals (Sweden)

    Ryan R Bart

    Full Text Available Higher global temperatures and increased levels of disturbance are contributing to greater tree mortality in many forest ecosystems. These same drivers can also limit forest regeneration, leading to vegetation type conversion. For the Sierra Nevada of California, little is known about how type conversion may affect streamflow, a critical source of water supply for urban, agriculture and environmental purposes. In this paper, we examined the effects of tree-to-shrub type conversion, in combination with climate change, on streamflow in two lower montane forest watersheds in the Sierra Nevada. A spatially distributed ecohydrologic model was used to simulate changes in streamflow, evaporation, and transpiration following type conversion, with an explicit focus on the role of vegetation size and aspect. Model results indicated that streamflow may show negligible change or small decreases following type conversion when the difference between tree and shrub leaf areas is small, partly due to the higher stomatal conductivity and the deep rooting depth of shrubs. In contrast, streamflow may increase when post-conversion shrubs have a small leaf area relative to trees. Model estimates also suggested that vegetation change could have a greater impact on streamflow magnitude than the direct hydrologic impacts of increased temperatures. Temperature increases, however, may have a greater impact on streamflow timing. Tree-to-shrub type conversion increased streamflow only marginally during dry years (annual precipitation < 800 mm, with most streamflow change observed during wetter years. These modeling results underscore the importance of accounting for changes in vegetation communities to accurately characterize future hydrologic regimes for the Sierra Nevada.

  14. Effect of Tree-to-Shrub Type Conversion in Lower Montane Forests of the Sierra Nevada (USA) on Streamflow

    Science.gov (United States)

    Tague, Christina L.; Moritz, Max A.

    2016-01-01

    Higher global temperatures and increased levels of disturbance are contributing to greater tree mortality in many forest ecosystems. These same drivers can also limit forest regeneration, leading to vegetation type conversion. For the Sierra Nevada of California, little is known about how type conversion may affect streamflow, a critical source of water supply for urban, agriculture and environmental purposes. In this paper, we examined the effects of tree-to-shrub type conversion, in combination with climate change, on streamflow in two lower montane forest watersheds in the Sierra Nevada. A spatially distributed ecohydrologic model was used to simulate changes in streamflow, evaporation, and transpiration following type conversion, with an explicit focus on the role of vegetation size and aspect. Model results indicated that streamflow may show negligible change or small decreases following type conversion when the difference between tree and shrub leaf areas is small, partly due to the higher stomatal conductivity and the deep rooting depth of shrubs. In contrast, streamflow may increase when post-conversion shrubs have a small leaf area relative to trees. Model estimates also suggested that vegetation change could have a greater impact on streamflow magnitude than the direct hydrologic impacts of increased temperatures. Temperature increases, however, may have a greater impact on streamflow timing. Tree-to-shrub type conversion increased streamflow only marginally during dry years (annual precipitation < 800 mm), with most streamflow change observed during wetter years. These modeling results underscore the importance of accounting for changes in vegetation communities to accurately characterize future hydrologic regimes for the Sierra Nevada. PMID:27575592

  15. Cryptic elevational zonation in trapdoor spiders (Araneae, Antrodiaetidae, Aliatypus janus complex) from the California southern Sierra Nevada.

    Science.gov (United States)

    Starrett, James; Hayashi, Cheryl Y; Derkarabetian, Shahan; Hedin, Marshal

    2018-01-01

    The relative roles of ecological niche conservatism versus niche divergence in promoting montane speciation remains an important topic in biogeography. Here, our aim was to test whether lineage diversification in a species complex of trapdoor spiders corresponds with riverine barriers or with an ecological gradient associated with elevational tiering. Aliatypus janus was sampled from throughout its range, with emphasis on populations in the southern Sierra Nevada Mountains of California. We collected multi-locus genetic data to generate a species tree for A. janus and its close relatives. Coalescent based hypothesis tests were conducted to determine if genetic breaks within A. janus conform to riverine barriers. Ecological niche models (ENM) under current and Last Glacial Maximum (LGM) conditions were generated and hypothesis tests of niche conservatism and divergence were performed. Coalescent analyses reveal deeply divergent genetic lineages within A. janus, likely corresponding to cryptic species. Two primary lineages meet along an elevational gradient on the western slopes of the southern Sierra Nevada Mountains. ENMs under both current and LGM conditions indicate that these groups occupy largely non-overlapping niches. ENM hypothesis testing rejected niche identity between the two groups, and supported a sharp ecological gradient occurring where the groups meet. However, the niche similarity test indicated that the two groups may not inhabit different background niches. The Sierra Nevada Mountains provide a natural laboratory for simultaneously testing ecological niche divergence and conservatism and their role in speciation across a diverse range of taxa. Aliatypus janus represents a species complex with cryptic lineages that may have diverged due to parapatric speciation along an ecological gradient, or been maintained by the evolution of ecological niche differences following allopatric speciation. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Assessing the combined effect of dams and climate warming on streamflow in California's Sierra Nevada for regional-scale adaptation

    Science.gov (United States)

    Rheinheimer, D. E.; Viers, J. H.

    2012-12-01

    Dams and their operations harm river ecosystems, in part by altering the natural flow regimes that those ecosystems depend on. In the multi-reservoir water management systems of California's Sierra Nevada, greater emphasis is being placed on re-operating existing reservoir systems to recover downstream ecosystems. However, climate change is changing inflow patterns, affecting both ecosystems and traditional water system benefits across the region. As new reservoir operation schemes will be needed to manage for natural resources management objectives at the regional scale, characterizing historical and future environmental impacts of current operations across the region can aid in prioritizing planning efforts. We used a coarse-scale water resources simulation model developed for the western Sierra Nevada to explore the independent and combined effects of dams and climate warming on the flow regime directly below reservoirs, the focal point for instream flow requirements in operations licenses. We quantified changes to mean annual flow, annual low flow duration, annual runoff centroid timing, and weekly rate of decrease under binary combinations of management (unregulated/regulated) and climate (historical/future) conditions. We demonstrate that although rivers in the Sierra Nevada are currently managed in ways that are harmful to instream ecosystems, and that streamflow effects of operations are typically much worse than climate change effects, there are signals that reservoirs can potentially be used to help adapt to some of climate changes harmful effects with little additional effort in some cases. This study is the first step toward a better understanding of the environmental costs from and opportunities afforded by the current stock of reservoirs in a large hydroregion under changing social and environmental conditions.

  17. Effects of Varying Cloud Cover on Springtime Runoff in California's Sierra Nevada

    Science.gov (United States)

    Sumargo, E.; Cayan, D. R.

    2017-12-01

    This study investigates how cloud cover modifies snowmelt-runoff processes in Sierra Nevada watersheds during dry and wet periods. We use two of the California Department of Water Resources' (DWR's) quasi-operational models of the Tuolumne and Merced River basins developed from the USGS Precipitation-Runoff Modeling System (PRMS) hydrologic modeling system. Model simulations are conducted after a validated optimization of model performance in simulating recent (1996-2014) historical variability in the Tuolumne and Merced basins using solar radiation (Qsi) derived from Geostationary Operational Environmental Satellite (GOES) remote sensing. Specifically, the questions we address are: 1) how sensitive are snowmelt and runoff in the Tuolumne and Merced River basins to Qsi variability associated with cloud cover variations?, and 2) does this sensitivity change in dry vs. wet years? To address these question, we conduct two experiments, where: E1) theoretical clear-sky Qsi is used as an input to PRMS, and E2) the annual harmonic cycle of Qsi is used as an input to PRMS. The resulting hydrographs from these experiments exhibit changes in peak streamflow timing by several days to a few weeks and smaller streamflow variability when compared to the actual flows and the original simulations. For E1, despite some variations, this pattern persists when the result is evaluated for dry-year and wet-year subsets, reflecting the consistently higher Qsi input available. For E2, the hydrograph shows a later spring-summer streamflow peak in the dry-year subset when compared to the original simulations, indicating the relative importance of the modulating effect of cloud cover on snowmelt-runoff in drier years.

  18. Interannual Variations in Aerosol Sources and Their Impact on Orographic Precipitation over California's Central Sierra Nevada

    Science.gov (United States)

    Creamean, J.; Ault, A. P.; White, A. B.; Neiman, P. J.; Minnis, P.; Prather, K. A.

    2014-12-01

    Aerosols that serve as cloud condensation nuclei (CCN) and ice nuclei (IN) have the potential to profoundly influence precipitation processes. Furthermore, changes in orographic precipitation have broad implications for reservoir storage and flood risks. As part of the CalWater I field campaign (2009-2011), the impacts of aerosol sources on precipitation were investigated in the California Sierra Nevada Mountains. In 2009, the precipitation collected on the ground was influenced by both local biomass burning and long-range transported dust and biological particles, while in 2010, by mostly local sources of biomass burning and pollution, and in 2011 by mostly long-range transport of dust and biological particles from distant sources. Although vast differences in the sources of residues were observed from year-to-year, dust and biological residues were omnipresent (on average, 55% of the total residues combined) and were associated with storms consisting of deep convective cloud systems and larger quantities of precipitation initiated in the ice phase. Further, biological residues were dominant during storms with relatively warm cloud temperatures (up to -15°C), suggesting biological components were more efficient IN than mineral dust. On the other hand, when precipitation quantities were lower, local biomass burning and pollution residues were observed (on average 31% and 9%, respectively), suggesting these residues potentially served as CCN at the base of shallow cloud systems and that lower level polluted clouds of storm systems produced less precipitation than non-polluted (i.e., marine) clouds. The direct connection of the sources of aerosols within clouds and precipitation type and quantity can be used in models to better assess how local emissions versus long-range transported dust and biological aerosols play a role in impacting regional weather and climate, ultimately with the goal of more accurate predictive weather forecast models and water resource

  19. Sierra Nevada snowpack and runoff prediction integrating basin-wide wireless-sensor network data

    Science.gov (United States)

    Yoon, Y.; Conklin, M. H.; Bales, R. C.; Zhang, Z.; Zheng, Z.; Glaser, S. D.

    2016-12-01

    We focus on characterizing snowpack and estimating runoff from snowmelt in high elevation area (>2100 m) in Sierra Nevada for daily (for use in, e.g. flood and hydropower forecasting), seasonal (supply prediction), and decadal (long-term planning) time scale. Here, basin-wide wireless-sensor network data (ARHO, http://glaser.berkeley.edu/wsn/) is integrated into the USGS Precipitation-Runoff Modeling System (PRMS), and a case study of the American River basin is presented. In the American River basin, over 140 wireless sensors have been planted in 14 sites considering elevation gradient, slope, aspect, and vegetation density, which provides spatially distributed snow depth, temperature, solar radiation, and soil moisture from 2013. 800 m daily gridded dataset (PRISM) is used as the climate input for the PRMS. Model parameters are obtained from various sources (e.g., NLCD 2011, SSURGO, and NED) with a regionalization method and GIS analysis. We use a stepwise framework for a model calibration to improve model performance and localities of estimates. For this, entire basin is divided into 12 subbasins that include full natural flow measurements. The study period is between 1982 and 2014, which contains three major storm events and recent severe drought. Simulated snow depth and snow water equivalent (SWE) are initially compared with the water year 2014 ARHO observations. The overall results show reasonable agreements having the Nash-Sutcliffe efficiency coefficient (NS) of 0.7, ranged from 0.3 to 0.86. However, the results indicate a tendency to underestimate the SWE in a high elevation area compared with ARHO observations, which is caused by the underestimated PRISM precipitation data. Precipitation at gauge-sparse regions (e.g., high elevation area), in general, cannot be well represented in gridded datasets. Streamflow estimates of the basin outlet have NS of 0.93, percent bias of 7.8%, and normalized root mean square error of 3.6% for the monthly time scale.

  20. Sensitivities of dry season runoff to precipitation and temperature in southern Sierra Nevada streams

    Science.gov (United States)

    Safeeq, M.; Hunsaker, C. T.; Bales, R. C.

    2016-12-01

    In a mediterranean climate, dry season runoff sustains water supply and supports aquatic habitat and other ecosystems. Precipitation and temperature directly, by regulating recharge and evapotranspiration (ET), and indirectly, by regulating amount and timing of snowmelt, control the dry season runoff in the Sierra Nevada. Here, we explored relative impacts of precipitation and temperature variability on dry season runoff using path analysis. Specific objectives include: (i) to quantify the direct and indirect impacts of precipitation and temperature on 7-day average minimum flow (Qmin) and (ii) to explore the role of preceding year Qmin on fall season runoff (QF). We used daily runoff, air temperature, precipitation, and snow water equivalent (SWE) over 2004-2015 for the ten catchments in the Kings River Experimental Watersheds. For path analysis model of Qmin, we defined annual precipitation and temperature as exogenous variables and peak SWE, day of snow disappearance, and Qmin as endogenous variables. For QF, we defined current year fall precipitation and preceding year Qmin as exogenous variables and current year QF as an endogenous variable. Path analysis results for Qmin show precipitation as a dominant driver when compared to temperature, peak SWE, and day of snow disappearance. However, in half of the catchments that are mostly located at higher elevations the impact of temperature on Qmin was either comparable or exceeded that of precipitation. This relatively high sensitivity of Qmin to air temperature in high elevation catchments is consistent with the earlier findings of increased ET in proportion to warming. The direct effects of peak SWE and day of snow disappearance on Qmin were limited, and indirect effects of temperature and precipitation via peak SWE and day of snow disappearance were not significant. The preceding year Qmin and fall precipitation showed comparable impacts on QF, indicating that the storage in the preceding year modulates current

  1. Isotopic variation in the Tuolumne Intrusive Suite, central Sierra Nevada, California

    Science.gov (United States)

    Kistler, R.W.; Chappell, B.W.; Peck, D.L.; Bateman, P.C.

    1986-01-01

    Granitoid rocks of the compositionally zoned Late Cretaceous Toulumne Intrusive Suite in the central Sierra Nevada, California, have initial87Sr/86Sr values (Sri) and143Nd/144Nd values (Ndi) that vary from 0.7057 to 0.7067 and from 0.51239 to 0.51211 respectively. The observed variation of both Sri and Ndi and of chemical composition in rocks of the suite cannot be due to crystal fractionation of magma solely under closed system conditons. The largest variation in chemistry, Ndi, and Sri is present in the outer-most equigranular units of the Tuolumne Intrusive Suite. Sri varies positively with SiO2, Na2O, K2O, and Rb concentrations, and negatively with Ndi, Al2O3, Fe2O3, MgO, FeO, CaO, MnO, P2O5, TiO2, and Sr concentrations. This covariation of Sri, Ndi and chemistry can be modeled by a process of simple mixing of basaltic and granitic magmas having weight percent SiO2 of 48.0 and 73.3 respectively. Isotopic characteristic of the mafic magma are Sri=0.7047, Ndi=0.51269 and ??18O=6.0, and of the felsic magma are Sri=0.7068, Ndi=0.51212 and ??18O=8.9. The rocks sampled contain from 50 to 80% of the felsic component. An aplite in the outer equigranular unit of the Tuolumne Intrusive Suite apparently was derived by fractional crystallization of plagioclase and hornblende from magma with granudiorite composition that was a product of mixing of the magmas described above. Siliceous magmas derived from the lower crust, having a maximum of 15 percent mantle-derived mafic component, are represented by the inner prophyritic units of the Tuolumne Intrusive Suite. ?? 1986 Springer-Verlag.

  2. The accuracy of matrix population model projections for coniferous trees in the Sierra Nevada, California

    Science.gov (United States)

    van Mantgem, P.J.; Stephenson, N.L.

    2005-01-01

    1 We assess the use of simple, size-based matrix population models for projecting population trends for six coniferous tree species in the Sierra Nevada, California. We used demographic data from 16 673 trees in 15 permanent plots to create 17 separate time-invariant, density-independent population projection models, and determined differences between trends projected from initial surveys with a 5-year interval and observed data during two subsequent 5-year time steps. 2 We detected departures from the assumptions of the matrix modelling approach in terms of strong growth autocorrelations. We also found evidence of observation errors for measurements of tree growth and, to a more limited degree, recruitment. Loglinear analysis provided evidence of significant temporal variation in demographic rates for only two of the 17 populations. 3 Total population sizes were strongly predicted by model projections, although population dynamics were dominated by carryover from the previous 5-year time step (i.e. there were few cases of recruitment or death). Fractional changes to overall population sizes were less well predicted. Compared with a null model and a simple demographic model lacking size structure, matrix model projections were better able to predict total population sizes, although the differences were not statistically significant. Matrix model projections were also able to predict short-term rates of survival, growth and recruitment. Mortality frequencies were not well predicted. 4 Our results suggest that simple size-structured models can accurately project future short-term changes for some tree populations. However, not all populations were well predicted and these simple models would probably become more inaccurate over longer projection intervals. The predictive ability of these models would also be limited by disturbance or other events that destabilize demographic rates. ?? 2005 British Ecological Society.

  3. Extent, timing, and climatic significance of latest Pleistocene and Holocene glaciation in the Sierra Nevada, California

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Douglas Howe [Univ. of Washington, Seattle, WA (United States)

    1995-01-01

    Despite more than a century of study, scant attention has been paid to the glacial record in the northern end of the Sierra Nevada, and to the smaller moraines deposited after the retreat of the Tioga (last glacial maximum) glaciers. Equilibrium-line altitude (ELA) estimates of the ice fields indicate that the Tioga ELA gradients there are consistent with similar estimates for the southern half of the range, and with an intensification of the modern temperature/precipitation pattern in the region. The Recess Peak advance has traditionally been considered to be mid-Neoglacial age, about 2--3,000 yr B.P., on the basis of relative weathering estimates. Sediment cores of lakes dammed behind moraines correlative with Recess Peak in four widely spaced sites yields a series of high-resolution AMS radiocarbon dates which demonstrate that Recess Peak glaciers retreated before ~13,100 cal yr B.P.. This minimum limiting age indicates that the advance predates the North Atlantic Younger Dryas cooling. It also implies that there have been no advances larger than the Matthes in the roughly 12,000 year interval between it and the Recess Peak advance. This finding casts doubt on several recent studies that claim Younger Dryas glacier advances in western North America. The 13,100 cal yr B.P. date is also a minimum age for deglaciation of the sample sites used to calibrate the in situ production rates of cosmogenic 10Be and 26Al. The discrepancy between this age and the 11,000 cal yr B.P. exposure age assumed in the original calibration introduces a large (> 19%) potential error in late-Pleistocene exposure ages calculated using these production rates.

  4. Spatiotemporal patterns of precipitation inferred from streamflow observations across the Sierra Nevada mountain range

    Science.gov (United States)

    Henn, Brian; Clark, Martyn P.; Kavetski, Dmitri; Newman, Andrew J.; Hughes, Mimi; McGurk, Bruce; Lundquist, Jessica D.

    2018-01-01

    Given uncertainty in precipitation gauge-based gridded datasets over complex terrain, we use multiple streamflow observations as an additional source of information about precipitation, in order to identify spatial and temporal differences between a gridded precipitation dataset and precipitation inferred from streamflow. We test whether gridded datasets capture across-crest and regional spatial patterns of variability, as well as year-to-year variability and trends in precipitation, in comparison to precipitation inferred from streamflow. We use a Bayesian model calibration routine with multiple lumped hydrologic model structures to infer the most likely basin-mean, water-year total precipitation for 56 basins with long-term (>30 year) streamflow records in the Sierra Nevada mountain range of California. We compare basin-mean precipitation derived from this approach with basin-mean precipitation from a precipitation gauge-based, 1/16° gridded dataset that has been used to simulate and evaluate trends in Western United States streamflow and snowpack over the 20th century. We find that the long-term average spatial patterns differ: in particular, there is less precipitation in the gridded dataset in higher-elevation basins whose aspect faces prevailing cool-season winds, as compared to precipitation inferred from streamflow. In a few years and basins, there is less gridded precipitation than there is observed streamflow. Lower-elevation, southern, and east-of-crest basins show better agreement between gridded and inferred precipitation. Implied actual evapotranspiration (calculated as precipitation minus streamflow) then also varies between the streamflow-based estimates and the gridded dataset. Absolute uncertainty in precipitation inferred from streamflow is substantial, but the signal of basin-to-basin and year-to-year differences are likely more robust. The findings suggest that considering streamflow when spatially distributing precipitation in complex terrain

  5. Conservation of avian diversity in the Sierra Nevada: moving beyond a single-species management focus

    Science.gov (United States)

    White, Angela M.; Zipkin, Elise F.; Manley, Patricia N.; Schlesinger, Matthew D.

    2013-01-01

    Background: As a result of past practices, many of the dry coniferous forests of the western United States contain dense, even-aged stands with uncharacteristically high levels of litter and downed woody debris. These changes to the forest have received considerable attention as they elevate concerns regarding the outcome of wildland fire. However, attempts to reduce biomass through fuel reduction (i.e., thinning of trees) are often opposed by public interest groups whose objectives include maintaining habitat for species of concern such as the spotted owl, Strix occidentalis, the northern goshawk, Accipiter gentilis, and the Pacific fisher, Martes pennanti. Whether protection of these upper-trophic level species confers adequate conservation of avian forest diversity is unknown. Methodology and Principal Findings: We use a multi-species occurrence model to estimate the habitat associations of 47 avian species detected at 742 sampling locations within an 880-km2 area in the Sierra Nevada. Our approach, which accounts for variations in detectability of species, estimates occurrence probabilities of all species in a community by linking species occurrence models into one hierarchical community model, thus improving inferences on all species, especially those that are rare or observed infrequently. We address how the avian community is influenced by covariates related to canopy cover, tree size and shrub cover while accounting for the impacts of abiotic variables known to affect species distributions. Conclusions and Significance: Environmental parameters estimated through our approach emphasize the importance of within and between stand-level heterogeneity in meeting biodiversity objectives and suggests that many avian species would increase under more open canopy habitat conditions than those favored by umbrella species of high conservation concern. Our results suggest that a more integrated approach that emphasizes maintaining a diversity of habitats across

  6. Hillslope Erosion and Water Quality from the Rim Fire, Sierra Nevada, CA

    Science.gov (United States)

    Kuhn, T. J.; Austin, L. J.; Forrester, H.; DeLong, S. B.; Lever, R.; Roche, J. W.

    2014-12-01

    The Rim Fire in 2013 burned approximately 1036 km2 in the Sierra Nevada (including 312 km2 within Yosemite National Park), generating considerable public concern regarding potential impacts to the Tuolumne River watershed, in terms of water quality and water supply infrastructure serving the City of San Francisco. Land management responses included a multi-million dollar watershed treatment project on USFS lands near Cherry Creek, with similar actions suggested for areas in the Hetch Hetchy and Lake Eleanor watersheds. In response to the concern that the post-burn landscape will negatively impact water quality, we are investigating hydrologic effects and hillslope erosion in two small burned basins (2.2 and 5.2 km2) within the Tuolumne River basin in Yosemite National Park. Within a month after fire containment, sites were equipped with instrumentation to record stream stage, turbidity, and total suspended sediment. We also installed 21 sediment fences that trap all sediment silt sized and larger on moderate (20%) to steep (50%) hillslopes from 100 m2 plots within moderate and high severity burn areas. Accumulated sediment is collected, weighed, and sub-sampled after each storm event, and, analyzed for dry weight, particle size, gravimetric water content, bulk density, pH, color, carbon and nitrogen content from % fine organics, and % coarse organics. As of July 31, 2014, four discrete storm events had been sampled. Data are used to calculate annual sediment yield, and to investigate organic carbon storage, deposition, and transport. We are also collecting repeat terrestrial laser scans to assess topographic change and identify the hillslope processes that contribute to erosion and deposition at plot- and hillslope-scale. These findings provide analogs for possible changes in adjacent burned areas and to inform management decisions in response to future fires and potential impacts to water quality in areas valued by the park, the City of San Francisco and other

  7. Conservation of avian diversity in the Sierra Nevada: moving beyond a single-species management focus.

    Directory of Open Access Journals (Sweden)

    Angela M White

    Full Text Available As a result of past practices, many of the dry coniferous forests of the western United States contain dense, even-aged stands with uncharacteristically high levels of litter and downed woody debris. These changes to the forest have received considerable attention as they elevate concerns regarding the outcome of wildland fire. However, attempts to reduce biomass through fuel reduction (i.e., thinning of trees are often opposed by public interest groups whose objectives include maintaining habitat for species of concern such as the spotted owl, Strix occidentalis, the northern goshawk, Accipiter gentilis, and the Pacific fisher, Martes pennanti. Whether protection of these upper-trophic level species confers adequate conservation of avian forest diversity is unknown.We use a multi-species occurrence model to estimate the habitat associations of 47 avian species detected at 742 sampling locations within an 880-km(2 area in the Sierra Nevada. Our approach, which accounts for variations in detectability of species, estimates occurrence probabilities of all species in a community by linking species occurrence models into one hierarchical community model, thus improving inferences on all species, especially those that are rare or observed infrequently. We address how the avian community is influenced by covariates related to canopy cover, tree size and shrub cover while accounting for the impacts of abiotic variables known to affect species distributions.Environmental parameters estimated through our approach emphasize the importance of within and between stand-level heterogeneity in meeting biodiversity objectives and suggests that many avian species would increase under more open canopy habitat conditions than those favored by umbrella species of high conservation concern. Our results suggest that a more integrated approach that emphasizes maintaining a diversity of habitats across environmental gradients and minimizing urbanization may have a

  8. On the relative contributions of wind vs. animals to seed dispersal of four Sierra Nevada pines.

    Science.gov (United States)

    Vander Wall, Stephen B

    2008-07-01

    Selective pressures that influence the form of seed dispersal syndromes are poorly understood. Morphology of plant propagules is often used to infer the means of dispersal, but morphology can be misleading. Several species of pines, for example, have winged seeds adapted for wind dispersal but owe much of their establishment to scatter-hoarding animals. Here the relative importance of wind vs. animal dispersal is assessed for four species of pines of the eastern Sierra Nevada that have winged seeds but differed in seed size: lodgepole pine (Pinus contorta murrayana, 8 mg); ponderosa pine (Pinus ponderosa ponderosa, 56 mg); Jeffrey pine (Pinus jeffreyi, 160 mg); and sugar pine (Pinus lambertiana, 231 mg). Pre-dispersal seed mortality eliminated much of the ponderosa pine seed crop (66%), but had much less effect on Jeffrey pine (32% of seeds destroyed), lodgepole pine (29%), and sugar pine (7%). When cones opened most filled seeds were dispersed by wind. Animals removed > 99% of wind-dispersed Jeffrey and sugar pine seeds from the ground within 60 days, but animals gathered only 93% of lodgepole pine seeds and 38% of ponderosa pine seeds during the same period. Animals gathered and scatter hoarded radioactively labeled ponderosa, Jeffrey, and sugar pine seeds, making a total of 2103 caches over three years of study. Only three lodgepole pine caches were found. Caches typically contained 1-4 seeds buried 5-20 mm deep, depths suitable for seedling emergence. Although Jeffrey and sugar pine seeds are initially wind dispersed, nearly all seedlings arise from animal caches. Lodgepole pine is almost exclusively wind dispersed, with animals acting as seed predators. Animals treated ponderosa pine in an intermediate fashion. Two-phased dispersal of large, winged pine seeds appears adaptive; initial wind dispersal helps to minimize pre-dispersal seed mortality whereas scatter hoarding by animals places seeds in sites with a higher probability of seedling establishment.

  9. Forest thinning and soil respiration in a ponderosa pine plantation in the Sierra Nevada.

    Science.gov (United States)

    Tang, Jianwu; Qi, Ye; Xu, Ming; Misson, Laurent; Goldstein, Allen H

    2005-01-01

    Soil respiration is controlled by soil temperature, soil water, fine roots, microbial activity, and soil physical and chemical properties. Forest thinning changes soil temperature, soil water content, and root density and activity, and thus changes soil respiration. We measured soil respiration monthly and soil temperature and volumetric soil water continuously in a young ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws.) plantation in the Sierra Nevada Mountains in California from June 1998 to May 2000 (before a thinning that removed 30% of the biomass), and from May to December 2001 (after thinning). Thinning increased the spatial homogeneity of soil temperature and respiration. We conducted a multivariate analysis with two independent variables of soil temperature and water and a categorical variable representing the thinning event to simulate soil respiration and assess the effect of thinning. Thinning did not change the sensitivity of soil respiration to temperature or to water, but decreased total soil respiration by 13% at a given temperature and water content. This decrease in soil respiration was likely associated with the decrease in root density after thinning. With a model driven by continuous soil temperature and water time series, we estimated that total soil respiration was 948, 949 and 831 g C m(-2) year(-1) in the years 1999, 2000 and 2001, respectively. Although thinning reduced soil respiration at a given temperature and water content, because of natural climate variability and the thinning effect on soil temperature and water, actual cumulative soil respiration showed no clear trend following thinning. We conclude that the effect of forest thinning on soil respiration is the combined result of a decrease in root respiration, an increase in soil organic matter, and changes in soil temperature and water due to both thinning and interannual climate variability.

  10. Effects of copper on species composition of periphyton in a Sierra Nevada, California, stream

    Energy Technology Data Exchange (ETDEWEB)

    Leland, H.V.; Carter, J.L.

    1984-06-01

    Changes in species composition of the periphyton of an oliotrophic, Sierra Nevada stream continuously dosed for 1 year at three concentrations of copper (2.5, 5 and 10..mu..g 1/sup -1/ Cu/sub T/; approximately 12, 25 and 50 ng 1/sup -1/ Cu/sup 2 +/) were determined. The numerically most abundant taxa were Bacillariophyceae (Achnanthes minutissima, Cocconeis placentula, Cymbella microcephala, C. sinuata, Fragilaria construens, F. crotonensis, Navicula spp., Synedra acus and S. rumpens), and the Cyanophyta Lynbya spp., a co-dominant during spring and summer. Population densities of Lyngbya spp. were markedly reduced at all test concentrations of copper. Population densities of the principal Chlorophyta (Spirogyra spp. and Cladophora spp.) and the diatom Amphipleura pellucida were reduced at 5 ..mu..g 1/sup -1/ Cu/sub T/. Of the twenty-two most abundant taxa, sixteen were reduced in abundance by continuous exposure to 10 ..mu..g 1/sup -1/ Cu/sub T/. There was no commensurate reduction in standing crop (total number of individuals of all taxa). Achnanthes minutissima, a co-dominant in the control, was the primary replacement species. Other taxa that were more abundant at 5 ..mu..g 1/sup -1/ Cu/sub T/ than in the control were Ceratoneis arcus, Cocconeis placentula, Navicula spp. and Synedra rumpens. Only A. minutissima and Calothrix spp. were more abundant at l10 ..mu..g 1/sup -1/ than in the control. Three resemblance measures (Canberra metric, Bray-Curtis and Dice) and diversity (Brillouin's) were evaluated for detecting differences in species composition among experimental stream sections. The Canberra metric, an index sensitive to proportional rather than absolute differences, was the most informative of these indices.

  11. Snowmelt response to simulated warming across a large elevation gradient, southern Sierra Nevada, California

    Directory of Open Access Journals (Sweden)

    K. N. Musselman

    2017-12-01

    Full Text Available In a warmer climate, the fraction of annual meltwater produced at high melt rates in mountainous areas is projected to decline due to a contraction of the snow-cover season, causing melt to occur earlier and under lower energy conditions. How snowmelt rates, including extreme events relevant to flood risk, may respond to a range of warming over a mountain front is poorly known. We present a model sensitivity study of snowmelt response to warming across a 3600 m elevation gradient in the southern Sierra Nevada, USA. A snow model was run for three distinct years and verified against extensive ground observations. To simulate the impact of climate warming on meltwater production, measured meteorological conditions were modified by +1 to +6 °C. The total annual snow water volume exhibited linear reductions (−10 % °C−1 consistent with previous studies. However, the sensitivity of snowmelt rates to successive degrees of warming varied nonlinearly with elevation. Middle elevations and years with more snowfall were prone to the largest reductions in snowmelt rates, with lesser changes simulated at higher elevations. Importantly, simulated warming causes extreme daily snowmelt (99th percentiles to increase in spatial extent and intensity, and shift from spring to winter. The results offer insight into the sensitivity of mountain snow water resources and how the rate and timing of water availability may change in a warmer climate. The identification of future climate conditions that may increase extreme melt events is needed to address the climate resilience of regional flood control systems.

  12. Inferring ecological relationships from occupancy patterns for California Black Rails in the Sierra Nevada foothills

    Science.gov (United States)

    Richmond, Orien Manu Wright

    The secretive California Black Rail (Laterallus jamaicensis coturniculus ) has a disjunct and poorly understood distribution. After a new population was discovered in Yuba County in 1994, we conducted call playback surveys from 1994--2006 in the Sierra foothills and Sacramento Valley region to determine the distribution and residency of Black Rails, estimate densities, and obtain estimates of site occupancy and detection probability. We found Black Rails at 164 small, widely scattered marshes distributed along the lower western slopes of the Sierra Nevada foothills, from just northeast of Chico (Butte County) to Rocklin (Placer County). Marshes were surrounded by a matrix of unsuitable habitat, creating a patchy or metapopulation structure. We observed Black Rails nesting and present evidence that they are year-round residents. Assuming perfect detectability we estimated a lower-bound mean Black Rail density of 1.78 rails ha-1, and assuming a detection probability of 0.5 we estimated a mean density of 3.55 rails ha-1. We test if the presence of the larger Virginia Rail (Laterallus limicola) affects probabilities of detection or occupancy of the smaller California Black Rail in small freshwater marshes that range in size from 0.013-13.99 ha. We hypothesized that Black Rail occupancy should be lower in small marshes when Virginia Rails are present than when they are absent, because resources are presumably more limited and interference competition should increase. We found that Black Rail detection probability was unaffected by the detection of Virginia Rails, while, surprisingly, Black and Virginia Rail occupancy were positively associated even in small marshes. The average probability of Black Rail occupancy was higher when Virginia Rails were present (0.74 +/- 0.053) than when they were absent (0.36 +/- 0.069), and for both species occupancy increased with marsh size. We assessed the impact of winter (November-May) cattle grazing on occupancy of California Black

  13. Ozone, nitric acid, and ammonia air pollution is unhealthy for people and ecosystems in southern Sierra Nevada, California

    Energy Technology Data Exchange (ETDEWEB)

    Cisneros, Ricardo, E-mail: rcisneros@fs.fed.u [USDA Forest Service, Pacific Southwest Region, 1600 Tollhouse Road, Clovis, CA 93611 (United States); Bytnerowicz, Andrzej, E-mail: abytnerowicz@fs.fed.u [USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Dr., Riverside, CA 92507 (United States); Schweizer, Donald, E-mail: dschweizer@fs.fed.u [USDA Forest Service, Pacific Southwest Region, 1600 Tollhouse Road, Clovis, CA 93611 (United States); Zhong, Sharon, E-mail: zhongs@msu.ed [Department of Geography, Michigan State University, 116 Geography Building East, Lansing, MI 48824-1117 (United States); Traina, Samuel, E-mail: straina@ucmerced.ed [Environmental Systems Graduate Group, University of California Merced, 5200 North Lake Road, Merced, CA 95343 (United States); Bennett, Deborah H., E-mail: dhbennett@ucdavis.ed [Department of Public Health Sciences, University of California Davis, One Shields Avenue, TB 169 Davis, CA 95616 (United States)

    2010-10-15

    Two-week average concentrations of ozone (O{sub 3}), nitric acid vapor (HNO{sub 3}) and ammonia (NH{sub 3}) were measured with passive samplers during the 2002 summer season across the central Sierra Nevada Mountains, California, along the San Joaquin River drainage. Elevated concentrations of the pollutants were determined with seasonal means for individual sites ranging between 62 and 88 ppb for O{sub 3}, 1.0-3.8 {mu}g m{sup -3} for HNO{sub 3}, and 2.6-5.2 {mu}g m{sup -3} for NH{sub 3}. Calculated O{sub 3} exposure indices were very high, reaching SUM00-191 ppm h, SUM60-151 ppm h, and W126-124 ppm h. Calculated nitrogen (N) dry deposition ranged from 1.4 to 15 kg N ha{sup -1} for maximum values, and 0.4-8 kg N ha{sup -1} for minimum values; potentially exceeding Critical Loads (CL) for nutritional N. The U.S., California, and European 8 h O{sub 3} human health standards were exceeded during 104, 108, and 114 days respectively, indicating high risk to humans from ambient O{sub 3}. - Ozone concentrations remained unchanged while those of nitric acid vapor and ammonia decreased along the river drainage crossing the Sierra Nevada Mountains.

  14. Ozone, nitric acid, and ammonia air pollution is unhealthy for people and ecosystems in southern Sierra Nevada, California

    International Nuclear Information System (INIS)

    Cisneros, Ricardo; Bytnerowicz, Andrzej; Schweizer, Donald; Zhong, Sharon; Traina, Samuel; Bennett, Deborah H.

    2010-01-01

    Two-week average concentrations of ozone (O 3 ), nitric acid vapor (HNO 3 ) and ammonia (NH 3 ) were measured with passive samplers during the 2002 summer season across the central Sierra Nevada Mountains, California, along the San Joaquin River drainage. Elevated concentrations of the pollutants were determined with seasonal means for individual sites ranging between 62 and 88 ppb for O 3 , 1.0-3.8 μg m -3 for HNO 3 , and 2.6-5.2 μg m -3 for NH 3 . Calculated O 3 exposure indices were very high, reaching SUM00-191 ppm h, SUM60-151 ppm h, and W126-124 ppm h. Calculated nitrogen (N) dry deposition ranged from 1.4 to 15 kg N ha -1 for maximum values, and 0.4-8 kg N ha -1 for minimum values; potentially exceeding Critical Loads (CL) for nutritional N. The U.S., California, and European 8 h O 3 human health standards were exceeded during 104, 108, and 114 days respectively, indicating high risk to humans from ambient O 3 . - Ozone concentrations remained unchanged while those of nitric acid vapor and ammonia decreased along the river drainage crossing the Sierra Nevada Mountains.

  15. Holocene vegetation and climate change recorded in alpine bog sediments from the Borreguiles de la Virgen, Sierra Nevada, southern Spain

    Science.gov (United States)

    Jiménez-Moreno, Gonzalo; Anderson, R. Scott

    2012-01-01

    High-resolution pollen and magnetic susceptibility (MS) analyses have been carried out on a sediment core taken from a high-elevation alpine bog area located in Sierra Nevada, southern Spain. The earliest part of the record, from 8200 to about 7000 cal yr BP, is characterized by the highest abundance of arboreal pollen and Pediastrum, indicating the warmest and wettest conditions in the area at that time. The pollen record shows a progressive aridification since 7000 cal yr BP that occurred in two steps, first shown by a decrease in Pinus, replaced by Poaceae from 7000 to 4600 cal yr BP and then by Cyperaceae, Artemisia and Amaranthaceae from 4600 to 1200 cal yr BP. Pediastrum also decreased progressively and totally disappeared at ca. 3000 yr ago. The progressive aridification is punctuated by periodically enhanced drought at ca. 6500, 5200 and 4000 cal yr BP that coincide in timing and duration with well-known dry events in the Mediterranean and other areas. Since 1200 cal yr BP, several changes are observed in the vegetation that probably indicate the high-impact of humans in the Sierra Nevada, with pasturing leading to nutrient enrichment and eutrophication of the bog, Pinus reforestation and Olea cultivation at lower elevations.

  16. Estimating contribution of wildland fires to ambient ozone levels in National Parks in the Sierra Nevada, California

    International Nuclear Information System (INIS)

    Preisler, Haiganoush K.; Zhong Shiyuan; Esperanza, Annie; Brown, Timothy J.; Bytnerowicz, Andrzej; Tarnay, Leland

    2010-01-01

    Data from four continuous ozone and weather monitoring sites operated by the National Park Service in Sierra Nevada, California, are used to develop an ozone forecasting model and to estimate the contribution of wildland fires on ambient ozone levels. The analyses of weather and ozone data pointed to the transport of ozone precursors from the Central Valley as an important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire. - We have demonstrated that it is possible to produce accurate forecasts of next-day hourly ozone levels in the Sierra Nevada, CA, during fire season.

  17. Estimating contribution of wildland fires to ambient ozone levels in National Parks in the Sierra Nevada, California

    Energy Technology Data Exchange (ETDEWEB)

    Preisler, Haiganoush K., E-mail: hpreisler@fs.fed.u [USDA Forest Service, Pacific Southwest Research Station, 800 Buchanan St, Albany, CA 94710 (United States); Zhong Shiyuan, E-mail: zhongs@msu.ed [Department of Geography, Michigan State University, 116 Geography Building, East Lansing, MI 48824-1117 (United States); Esperanza, Annie, E-mail: annie_esperanza@nps.go [Sequoia and Kings Canyon National Parks, 47050 Generals Highway Three Rivers, CA 93271 (United States); Brown, Timothy J., E-mail: tim.brown@dri.ed [Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89521-10095 (United States); Bytnerowicz, Andrzej, E-mail: abytnerowicz@fs.fed.u [USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States); Tarnay, Leland, E-mail: Leland_Tarnay@nps.go [Yosemite National Park, El Portal, CA 95318 (United States)

    2010-03-15

    Data from four continuous ozone and weather monitoring sites operated by the National Park Service in Sierra Nevada, California, are used to develop an ozone forecasting model and to estimate the contribution of wildland fires on ambient ozone levels. The analyses of weather and ozone data pointed to the transport of ozone precursors from the Central Valley as an important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire. - We have demonstrated that it is possible to produce accurate forecasts of next-day hourly ozone levels in the Sierra Nevada, CA, during fire season.

  18. Groundwater-quality data for the Sierra Nevada study unit, 2008: Results from the California GAMA program

    Science.gov (United States)

    Shelton, Jennifer L.; Fram, Miranda S.; Munday, Cathy M.; Belitz, Kenneth

    2010-01-01

    Groundwater quality in the approximately 25,500-square-mile Sierra Nevada study unit was investigated in June through October 2008, as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The Sierra Nevada study was designed to provide statistically robust assessments of untreated groundwater quality within the primary aquifer systems in the study unit, and to facilitate statistically consistent comparisons of groundwater quality throughout California. The primary aquifer systems (hereinafter, primary aquifers) are defined by the depth of the screened or open intervals of the wells listed in the California Department of Public Health (CDPH) database of wells used for public and community drinking-water supplies. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifers; shallow groundwater may be more vulnerable to contamination from the surface. In the Sierra Nevada study unit, groundwater samples were collected from 84 wells (and springs) in Lassen, Plumas, Butte, Sierra, Yuba, Nevada, Placer, El Dorado, Amador, Alpine, Calaveras, Tuolumne, Madera, Mariposa, Fresno, Inyo, Tulare, and Kern Counties. The wells were selected on two overlapping networks by using a spatially-distributed, randomized, grid-based approach. The primary grid-well network consisted of 30 wells, one well per grid cell in the study unit, and was designed to provide statistical representation of groundwater quality throughout the entire study unit. The lithologic grid-well network is a secondary grid that consisted of the wells in the primary grid-well network plus 53 additional wells and was designed to provide statistical representation of groundwater quality in each of the four major lithologic units in the Sierra

  19. Short-term effects of fire and forest thinning on truffle abundance and consumption by Neotamias speciosus in the Sierra Nevada of California

    Science.gov (United States)

    Marc D. Meyer; Malcolm P. North; Douglas A. Kelt

    2005-01-01

    In many western North American forests, prescribed burning and mechanical thinning are widely used to reduce fuels and restore stand conditions after a century of fire suppression. Few studies have followed the relative impacts of these treatments on the production and consumption of truffles in forest ecosystems, particularly in the Sierra Nevada of California. Using...

  20. Canopy arthropod responses to thinning and burning treatments in old-growth mixed-conifer forest in the Sierra Nevada, California

    Science.gov (United States)

    Thomas Rambo; Timothy Schowalter; Malcolm North

    2014-01-01

    We compared canopy arthropod responses to common fuels reduction treatments at Teakettle Experimental Forest in the south-central Sierra Nevada of California. We sampled arthropod communities among four dominant overstory conifer species and three dominant understory angiosperm species before and after overstory or understory thinning or no thinning treatments followed...

  1. EFFECTS OF CLIMATE VARIABILITY ON THE CARBON DIOXIDE, WATER, AND SENSIBLE HEAT FLUXES ABOVE A PONDEROSA PINE PLANTATION IN THE SIERRA NEVADA, CA. (R826601)

    Science.gov (United States)

    AbstractFluxes of CO2, water vapor, and sensible heat were measured by the eddy covariance method above a young ponderosa pine plantation in the Sierra Nevada Mountains (CA) over two growing seasons (1 June¯10 September 1997 and 1 May&#...

  2. Studies on Colombian cryptogams XX. A transect analysis of the bryophyte vegetation along an altitudinal gradient on the Sierra Nevada de Santa Marta, Colombia

    NARCIS (Netherlands)

    Reenen, van G.B.A.; Gradstein, S.R.

    1983-01-01

    Along an altitudinal transect on the northern slope of the Sierra Nevada de Santa Marta, Colombia, 500-4100 m, five altitudinal bryophyte zones are distinguished – four forest zones and one páramo zone – based on ecosystem relevé analysis concerning species presence, substrate preference and

  3. Meta-analysis of California Spotted Owl (Strix occidentalis occidentalis) territory occupancy in the Sierra Nevada: habitat associations and their implications for forest management

    Science.gov (United States)

    Douglas J. Tempel; John J. Keane; R. J. Gutierrez; Jared D. Wolfe; Gavin M. Jones; Alexander Koltunov; Carlos M. Ramirez; William J. Berigan; Claire V. Gallagher; Thomas E. Munton; Paula A. Shaklee; Sheila A. Whitmore; M. Zachariah Peery

    2016-01-01

    We assessed the occupancy dynamics of 275 California Spotted Owl (Strix occidentalis occidentalis) territories in 4 study areas in the Sierra Nevada, California, USA, from 1993 to 2011. We used Landsat data to develop maps of canopy cover for each study area, which we then used to quantify annual territory-specific habitat...

  4. Landscape fuel reduction, forest fire, and biophysical linkages to local habitat use and local persistence of fishers (Pekania pennanti) in Sierra Nevada mixed-conifer forests

    Science.gov (United States)

    R.A. Sweitzer; B.J. Furnas; R.H. Barrett; Kathryn Purcell; Craig Thompson

    2016-01-01

    Fire suppression and logging have contributed to major changes in California’s Sierra Nevada forests. Strategically placed landscape treatments (SPLATS) are being used to reduce density of trees, shrubs, and surface fuels to limit wildfire intensity and spread, but may negatively impact fishers (Pekania pennanti). We used camera traps to survey for...

  5. Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

    Science.gov (United States)

    L. Liu; C.I. Millar; R.D. Westfall; H.A. Zebker

    2013-01-01

    Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at...

  6. Hydrogeologic influence on changes in snowmelt runoff with climate warming: Numerical experiments on a mid-elevation catchment in the Sierra Nevada, USA

    Science.gov (United States)

    S.M. Jepsen; T.C. Harmon; M.W. Meadows; C.T. Hunsaker

    2016-01-01

    The role of hydrogeology in mediating long-term changes in mountain streamflow, resulting from reduced snowfall in a potentially warmer climate, is currently not well understood. We explore this by simulating changes in stream discharge and evapotranspiration from a mid-elevation, 1-km2 catchment in the southern Sierra Nevada of California (USA)...

  7. Critical Loads of Acid Deposition for Wilderness Lakes in the Sierra Nevada (California) Estimated by the Steady-State Water Chemistry Model

    Science.gov (United States)

    Glenn D. Shaw; Ricardo Cisneros; Donald Schweizer; James O. Sickman; Mark E. Fenn

    2014-01-01

    Major ion chemistry (2000-2009) from 208 lakes (342 sample dates and 600 samples) in class I and II wilderness areas of the Sierra Nevada was used in the Steady-State Water Chemistry (SSWC) model to estimate critical loads for acid deposition and investigate the current vulnerability of high elevation lakes to acid deposition. The majority of the lakes were dilute (...

  8. Potential climatic refugia in semi-arid, temperate mountains: plant and arthropod assemblages associated with rock glaciers, talus slopes, and their forefield wetlands, Sierra Nevada, California, USA

    Science.gov (United States)

    Constance I. Millar; Robert D. Westfall; Angela Evenden; Jeffrey G. Holmquist; Jutta Schmidt-Gengenbach; Rebecca S. Franklin; Jan Nachlinger; Diane L. Delany

    2015-01-01

    Unique thermal and hydrologic regimes of rock-glacier and periglacial talus environments support little-studied mountain ecosystems. We report the first studies of vascular plant and arthropod diversity for these habitats in the central Sierra Nevada, California, USA. Surfaces of active rock glaciers develop scattered islands of soil that provide habitat for vegetation...

  9. Subpixel Snow-covered Area Including Differentiated Grain Size from AVIRIS Data Over the Sierra Nevada Mountain Range

    Science.gov (United States)

    Hill, R.; Calvin, W. M.; Harpold, A. A.

    2016-12-01

    Mountain snow storage is the dominant source of water for humans and ecosystems in western North America. Consequently, the spatial distribution of snow-covered area is fundamental to both hydrological, ecological, and climate models. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data were collected along the entire Sierra Nevada mountain range extending from north of Lake Tahoe to south of Mt. Whitney during the 2015 and 2016 snow-covered season. The AVIRIS dataset used in this experiment consists of 224 contiguous spectral channels with wavelengths ranging 400-2500 nanometers at a 15-meter spatial pixel size. Data from the Sierras were acquired on four days: 2/24/15 during a very low snow year, 3/24/16 near maximum snow accumulation, and 5/12/16 and 5/18/16 during snow ablation and snow loss. Previous retrieval of subpixel snow-covered area in alpine regions used multiple snow endmembers due to the sensitivity of snow spectral reflectance to grain size. We will present a model that analyzes multiple endmembers of varying snow grain size, vegetation, rock, and soil in segmented regions along the Sierra Nevada to determine snow-cover spatial extent, snow sub-pixel fraction and approximate grain size or melt state. The root mean squared error will provide a spectrum-wide assessment of the mixture model's goodness-of-fit. Analysis will compare snow-covered area and snow-cover depletion in the 2016 year, and annual variation from the 2015 year. Field data were also acquired on three days concurrent with the 2016 flights in the Sagehen Experimental Forest and will support ground validation of the airborne data set.

  10. Inexistence of permafrost at the top of the Veleta peak (Sierra Nevada)

    Science.gov (United States)

    Gómez-Ortiz, Antonio; Salvador-Franch, Ferran; Salvà-Catarineu, Montserrat; Oliva, Marc; Palacios, David; Tanarro, Luis Miguel; Schulte, Lothar

    2014-05-01

    Several deep drillings wew carried out along a latitudinal transect from Svalbard (78°N) to Sierra Nevada (37°N, Spain) within the project Permafrost and Climate Change in Europe (PACE). In this abstract we discuss the data corresponding to the drilling existing at the top of the Veleta peak, at an altitude of 3380 m. This drilling reach a depth of 114.5 m depth, although we analyze here the data of the first 60 m depth. UTL-1 loggers were installed at depths of 0.2, 0.6, 1.2, 2.6, 4, 7, 10, 13, 15, 20 and 60 m. The observation period spans from 2002 to 2013 with data being taken every 2 h. The most surficial loggersrecorded the largest annual temperature oscillations, reaching 22.6°C at 20 cm. Down to 10 m depth the annual temperature amplitude is still remarkable and seasonal temperature changes are even observed at depths of 15 to 20 m. Below this level the temperature remains constant. The logger installed at 60 m depth recorded small temperature changes between 2006 and 2009, oscillating between 2.38 and 2.61ºC. Since January 2010 the temperatures stabilized at 2.61°C. However, this slight temperature increase must be framed within the margin of instrumentation error of the devices. Data shows evidence of the inexistence ofpermanent negative temperatures at depth. In contrast to what happens in the nearby Veleta cirque floor (3100 m), where marginal permafrost conditions have been recorded, in the Veleta peak (3380 m) data points to the absence of a permafrost regime. This may be due to several factors: a) The existence of permafrost in the Veletacirque is directly related to the presence of fossil glacier ice corresponding to a glacier that existed there during the Little Ice Age. b ) The early melting of snow cover in the Veleta peak due to wind effect and incidence of solar radiation condition the absence of permafrost conditions at the summitin contrast to the Veleta cirquefloor, where the longer persistence of snow favours the presence of continuous

  11. Early Neogene unroofing of the Sierra Nevada de Santa Marta along the Bucaramanga -Santa Marta Fault

    Science.gov (United States)

    Piraquive Bermúdez, Alejandro; Pinzón, Edna; Bernet, Matthias; Kammer, Andreas; Von Quadt, Albrecht; Sarmiento, Gustavo

    2016-04-01

    Plate interaction between Caribbean and Nazca plates with Southamerica gave rise to an intricate pattern of tectonic blocks in the Northandean realm. Among these microblocks the Sierra Nevada de Santa Marta (SNSM) represents a fault-bounded triangular massif composed of a representative crustal section of the Northandean margin, in which a Precambrian to Late Paleozoic metamorphic belt is overlain by a Triassic to Jurassic magmatic arc and collateral volcanic suites. Its western border fault belongs to the composite Bucaramanga - Santa Marta fault with a combined left lateral-normal displacement. SE of Santa Marta it exposes remnants of an Oligocene marginal basin, which attests to a first Cenoizoic activation of this crustal-scale lineament. The basin fill consists of a sequence of coarse-grained cobble-pebble conglomerates > 1000 m thick that unconformably overlay the Triassic-Jurassic magmatic arc. Its lower sequence is composed of interbedded siltstones; topwards the sequence becomes dominated by coarser fractions. These sedimentary sequences yields valuable information about exhumation and coeval sedimentation processes that affected the massif's western border since the Upper Eocene. In order to analyse uplifting processes associated with tectonics during early Neogene we performed detrital zircon U-Pb geochronology, detrital thermochronology of zircon and apatites coupled with the description of a stratigraphic section and its facies composition. We compared samples from the Aracataca basin with analog sequences found at an equivalent basin at the Oca Fault at the northern margin of the SNSM. Our results show that sediments of both basins were sourced from Precambrian gneisses, along with Mesozoic acid to intermediate plutons; sedimentation started in the Upper Eocene-Oligocene according to palynomorphs, subsequently in the Upper Oligocene a completion of Jurassic to Cretaceous sources was followed by an increase of Precambrian input that became the dominant

  12. Holocene climate variability in the western Mediterranean through a multiproxy analysis from Padul peat bog (Sierra Nevada, Spain)

    Science.gov (United States)

    Ramos-Román, María J.; Jiménez-Moreno, Gonzalo; Camuera, Jon; García-Alix, Antonio; Anderson, R. Scott; Jiménez-Espejo, Francisco J.; Sachse, Dirk

    2017-04-01

    The Iberian Peninsula, located in the Mediterranean area, is an interesting location for paleoclimate studies due to its geographic situation between arid and humid climates. Sediments from peat bogs and lakes from Sierra Nevada, in southeastern Iberian Peninsula, have been very informative in terms of how vegetation and wetland environments were impacted by Holocene climate change. These studies are essential if we want to understand the past climate change in the area, which is the key to identify the possible environmental response of the Sierra Nevada ecosystems to future climate scenarios. Padul basin, located in the southwest of the Sierra Nevada mountain range, contains a ca. 100 m-thick peat bog sedimentary sequence that was deposited during the past 1 Ma making this area interesting for paleoenvironmental and paleoclimatic reconstructions. A new 43 m-long sedimentary record has recently been retrieved from the Padul peat bog. In this study we have developed a multiproxy analysis of the Holocene part of the Padul-15-05 core including pollen analysis, XRF-core scanner, magnetic susceptibility and organic geochemistry, supported by an age control based on AMS radiocarbon dates, providing with information about vegetation and climate variability during the past 9.9 cal ka BP. This multiproxy reconstruction of the Padul-15-05 evidences the Mediterranean as a sensitive area with respect to global-scale climate system, showing relevant climate episodes such as the ca. 8, 7.5, 6.5 and 5.5 cal ka BP events during the early and middle Holocene. The trend to aridification to the late Holocene is interrupted by more arid and humid periods as the Iberian Roman Humid Period (from ca. 3 to 1.6 cal ka BP), the Dark Ages (from ca. 1.5 to 1.1 cal ka BP), the Medieval Climate Anomaly (from ca. 1.1 to 1.3 cal ka BP) and the Little Ice Age period (from ca. 500 to 100 cal yr BP).

  13. Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

    Directory of Open Access Journals (Sweden)

    D. Obrist

    2009-05-01

    Full Text Available This study presents data on mercury (Hg concentrations, stochiometric relations to carbon (C and nitrogen (N, and Hg pool sizes in four Sierra Nevada forest sites of similar exposure and precipitation regimes, and hence similar atmospheric deposition, to evaluate how ecosystem parameters control Hg retention in ecosystems. In all four sites, the largest amounts of Hg reside in soils which account for 94–98% of ecosystem pools. Hg concentrations and Hg/C ratios increase in the following order: Green Needles/Leavesr2=0.58 and N and C (r2=0.64 in decomposing litter, but a positive correlation between litter Hg and N (r2=0.70. These inverse relations may reflect preferential retention of N and Hg over C during decomposition, or may be due to older age of decomposed litter layers which are exposed to longer-term atmospheric Hg deposition in the field. The results indicate that litter Hg levels depend on decomposition stage and may not follow generally observed positive relationships between Hg and organic C.

    Mineral soil layers show strong positive correlations of Hg to C across all sites and soil horizons (r2=0.83, but Hg concentrations are even more closely related to N with a similar slope to that observed in litter (r2=0.92. Soil N levels alone explain over 90% of Hg pool sizes across the four Sierra Nevada forest sites. This suggests that soil organic N and C groups provide sorption sites for Hg to retain atmospheric deposition. However, the patterns could be due to indirect relationships where high soil N and C levels reflect high ecosystem productivity which leads to corresponding high atmospheric Hg deposition inputs via leaf litterfall and plant senescence. Our results also show that two of the sites previously affected by

  14. Approach to seismic hazard analysis for dam safety in the Sierra Nevada and Modoc Plateau of California

    International Nuclear Information System (INIS)

    Savage, W.U.; McLaren, M.K.; Edwards, W.D.; Page, W.D.

    1991-01-01

    Pacific Gas and Electric Company's hydroelectric generating system involves about 150 dams located in the Sierra Nevada and Modoc Plateau region of central and northern California. The utility's strategy for earthquake hazard assessment is described. The approach includes the following strategies: integrating regional tectonics, seismic geology, historical seismicity, microseismicity, and crustal structure to form a comprehensive regional understanding of the neotectonic setting; performing local studies to acquire data as needed to reduce uncertainties in geologic and seismic parameters of fault characteristics near specific dam sites; applying and extending recently developed geologic, seismologic, and earthquake engineering technologies to the current regional and site-specific information to evaluate fault characteristics, to estimate maximum earthquakes, and to characterize ground motion; and encouraging multiple independent reviews of earthquake hazard studies by conducting peer reviews, making field sites available to regulating agencies, and publishing results, methods and data in open literature. 46 refs., 8 tabs

  15. Vegetation response to the 2016-2017 extreme Sierra Nevada snowfall event using multitemporal terrestrial laser scanning: initial results

    Science.gov (United States)

    Greenberg, J. A.; Hou, Z.; Ramirez, C.; Hart, R.; Marchi, N.; Parra, A. S.; Gutierrez, B.; Tompkins, R.; Harpold, A.; Sullivan, B. W.; Weisberg, P.

    2017-12-01

    The Sierra Nevada Mountains experienced record-breaking snowfall during the 2016-2017 winter after a prolonged period of drought. We hypothesized that at lower elevations, the increased snowmelt would result in a significant increase in biomass across vegetation strata, but at higher elevations, the snowpack would result in a diminished growing season, and yield a suppression of growth rates particularly in the understory vegetation. To test these hypotheses, we sampled sites across the Plumas National Forest and Lake Tahoe Basin using a terrestrial laser scanner (TLS) in the early growing season, and then rescanned these sites in the late growing season. Herein, we present initial, early results from this analysis, focusing on the biomass and height changes in trees.

  16. Photogrammetric Methodology for the Production of Geomorphologic Maps: Application to the Veleta Rock Glacier (Sierra Nevada, Granada, Spain

    Directory of Open Access Journals (Sweden)

    José Jesús Guerrero

    2009-10-01

    Full Text Available In this paper we present a stereo feature-based method using SIFT (Scale-invariant feature transform descriptors. We use automatic feature extractors, matching algorithms between images and techniques of robust estimation to produce a DTM (Digital Terrain Model using convergent shots of a rock glacier.The geomorphologic structure observed in this study is the Veleta rock glacier (Sierra Nevada, Granada, Spain. This rock glacier is of high scientific interest because it is the southernmost active rock glacier in Europe and it has been analyzed every year since 2001. The research on the Veleta rock glacier is devoted to the study of its displacement and cartography through geodetic and photogrammetric techniques.

  17. Delineation of the High Enthalpy Reservoirs of the Sierra Nevada Volcanic Geothermal System, South-Central Chile

    Science.gov (United States)

    Alam, M.; Muñoz, M.; Parada, M.

    2011-12-01

    Geothermal system associated with the Pleistocene-Holocene Sierra Nevada volcano (SNVGS) in the Araucanía Region of Chile has surface manifestations from the north-western flank of the volcano, up to Manzanar and Malalcahuello. Baños del Toro, located on the northwestern flank of the volcano, has numerous fumaroles and acid pools (acid sulfate waters, T=~90°C, pH=2.1, TDS=3080 mg/L); while Aguas de la Vaca, near the base of the volcano, has a bubbling spring (chloride-sulfate waters, T=~60°C, pH=7.0, TDS=950 mg/L). Five shallow (Geotermia) of the Ministry of Energy and Mining, Government of Chile.

  18. An ecologic study comparing distribution of Pasteurella trehalosi and Mannheimia haemolytica between Sierra Nevada bighorn sheep, White Mountain bighorn sheep, and domestic sheep.

    Science.gov (United States)

    Tomassini, Letizia; Gonzales, Ben; Weiser, Glen C; Sischo, William

    2009-10-01

    The prevalence and phenotypic variability of Pasteurella and Mannheimia isolates from Sierra Nevada bighorn sheep (Ovis canadensis sierrae), White Mountain bighorn sheep (Ovis canadensis nelsoni), and domestic sheep (Ovis aries) from California, USA, were compared. The White Mountain bighorn sheep population had a recent history of pneumonia-associated mortality, whereas the Sierra Nevada bighorn sheep population had no recent history of pneumonia-associated mortality. The domestic sheep flocks were pastured in areas geographically near both populations but were not known to have direct contact with either bighorn sheep population. Oropharyngeal swab samples were collected from healthy domestic and bighorn sheep and cultured to characterize bacterial species, hemolysis, biogroups, and biovariants. Pasteurella trehalosi and Mannheimia haemolytica were detected in all of the study populations, but the relative proportion of each bacterial species differed among sheep populations. Pasteurella trehalosi was more common than M. haemolytica in the bighorn sheep populations, whereas the opposite was true in domestic sheep. Mannheimia haemolytica was separated into 11 biogroups, and P. trehalosi was characterized into two biogroups. Biogroup distributions for M. haemolytica and P. trehalosi differed among the three populations; however, no difference was detected for the distribution of P. trehalosi biogroups between the Sierra Nevada bighorn sheep and domestic sheep. The prevalence odds ratios (pOR) for the distribution of M. haemolytica biogroups suggested little difference between White Mountain bighorn sheep and domestic sheep compared with Sierra Nevada bighorn sheep and domestic sheep, although these comparisons had relatively large confidence intervals for the point estimates. Hemolytic activity of the isolates was not different among the sheep populations for M. haemolytica but was different for P. trehalosi. No clear evidence of association was found in the

  19. Hydroclimatic alteration increases vulnerability of montane meadows in the Sierra Nevada, California

    Science.gov (United States)

    Viers, J. H.; Peek, R.; Purdy, S. E.; Emmons, J. D.; Yarnell, S. M.

    2012-12-01

    Meadow ecosystems of the Sierra Nevada (California, USA) have been maintained by the interplay of biotic and abiotic forces, where hydrological functions bridge aquatic and terrestrial realms. Meadows are not only key habitat for fishes, amphibians, birds, and mammals alike, but also provide enumerable ecosystem services to humans, not limited to regulating services (eg, water filtration), provisioning services (eg, grazing), and aesthetics. Using hydroclimatic models and spatial distribution models of indicator species, a range wide assessment was conducted to assess and synthesize the vulnerability of meadow ecosystems to hydroclimatic alteration, a result of regional climate change. Atmospheric warming is expected to result in a greater fraction of total precipitation falling as winter rain (rather than snow) and earlier snowmelt. These predicted changes will likely cause more precipitation-driven runoff in winter and reduced snowmelt runoff in spring, leading to reduced annual runoff and a general shift in runoff timing to earlier in the year. These profound effects have consequences for hydrological cycling and meadow functioning, though such changes will not occur steadily through time or uniformly across the range, and each individual meadow will respond as a function of its composition and land use history. Most vulnerable is groundwater recharge, a fundamental component of meadow hydrology. As a result of shortened snow melt period and absence of diel snowmelt fluxes that would otherwise gradually refill meadow aquifers, recharge is expected to decline due to less infiltration. Diminished water tables will likely stress hydric and mesic vegetation, promoting more xeric conditions. Coupled with greater magnitude stream flows, these conditions promote channel incision and ultimate state shift to non-meadow conditions. The biological effects of hydroclimatic alteration, such as lower mean annual flow and earlier timing, will result in an overall decrease in

  20. Occurrence patterns of Black-backed Woodpeckers in green forest of the Sierra Nevada Mountains, California, USA.

    Directory of Open Access Journals (Sweden)

    Alissa M. Fogg

    2014-12-01

    Full Text Available Black-backed Woodpeckers (Picoides arcticus are a rare habitat specialist typically found in moderate and high severity burned forest throughout its range. It also inhabits green forest but little is known about occurrence and habitat use patterns outside of burned areas, especially in the Sierra Nevada of California, USA. We used point count and playback surveys to detect Black-backed Woodpeckers during 2011 - 2013 on 460 transects on 10 national forest units. We defined green forest as areas that had not burned at moderate or high severity since 1991 and were more than 2 km from areas burned at moderate or high severity within the previous eight years (n = 386 transects. We used occupancy models to examine green forest habitat associations and found positive relationships with elevation, latitude, northern aspects, number of snags, tree diameter, lodgepole pine (Pinus contorta forest, and a negative relationship with slope. Estimated occupancy in green forest was higher than previously understood (0.21. In addition site colonization and extinction probability in green forest were low (0.05 and 0.19, respectively and suggest that many of the individuals detected in green forest were not just actively dispersing across the landscape in search of burned areas, but were occupying relatively stable home ranges. The association with high elevation and lodgepole pine forest may increase their exposure to climate change as these elevation forest types are predicted to decrease in extent over the next century. Although density is high in burned forest, green forest covers significantly more area in the Sierra Nevada and should be considered in efforts to conserve this rare species.

  1. Dispersal limitation does not control high elevational distribution of alien plant species in the southern Sierra Nevada, California

    Science.gov (United States)

    Rundel, Philip W.; Keeley, Jon E.

    2016-01-01

    Patterns of elevational distribution of alien plant species in the southern Sierra Nevada of California were used to test the hypothesis that alien plant species invading high elevations around the world are typically climate generalists capable of growing across a wide elevational range. The Sierra Nevada has been heavily impacted for more than a century and a half, first by heavy grazing up into high elevation meadows, followed by major logging, and finally, by impacts associated with recreational use. The comparative elevational patterns of distribution and growth form were compared for native and alien plant species in the four families (Asteraceae, Brassicaceae, Fabaceae, and Poaceae) that contribute the majority of naturalized aliens in the study area. The distribution of realized climatic niche breadth, as measured by elevational range of occurrence, was virtually identical for alien and native species, with both groups showing a roughly Gaussian distribution peaking with species whose range covers a span of 1500–1999 m. In contrast to alien species, which only rarely occurred at higher elevations, native species showed a distribution of upper elevation limits peaking at 3000–3499 m, an elevation that corresponds to the zone of upper montane and subalpine forests. Consistent with a hypothesis of abiotic limitations, only a few alien species have been ecologically successful invaders at subalpine and alpine elevations above 2500 m. The low diversity of aliens able to become established in these habitats is unlikely due to dispersal limitations, given the long history of heavy grazing pressure at high elevations across this region. Instead, this low diversity is hypothesized to be a function of life history traits and multiple abiotic stresses that include extremes of cold air and soil temperature, heavy snowfall, short growing seasons, and low resource availability. These findings have significant implications for resource managers.

  2. The Relationships Between Insoluble Precipitation Residues, Clouds, and Precipitation Over California's Southern Sierra Nevada During Winter Storms

    Science.gov (United States)

    Creamean, Jessie M.; White, Allen B.; Minnis, Patrick; Palikonda, Rabindra; Spangenberg, Douglas A.; Prather, Kimberly A.

    2016-01-01

    Ice formation in orographic mixed-phase clouds can enhance precipitation and depends on the type of aerosols that serve as ice nucleating particles (INP). The resulting precipitation from these clouds is a viable source of water, especially for regions such as the California Sierra Nevada. Thus, a better understanding of the sources of INP that impact orographic clouds is important for assessing water availability in California. This study presents a multi-site, multi-year analysis of single particle insoluble residues in precipitation samples that likely influenced cloud ice and precipitation formation above Yosemite National Park. Dust and biological particles represented the dominant fraction of the residues (64% on average). Cloud glaciation, determined using GOES satellite observations, not only depended on high cloud tops (greater than 6.2 km) and low temperatures (less than -26 C), but also on the composition of the dust and biological residues. The greatest prevalence of ice-phase clouds occurred in conjunction with biologically-rich residues and mineral dust rich in calcium, followed by iron and aluminosilicates. Dust and biological particles are known to be efficient INP, thus these residues are what likely influenced ice formation in clouds above the sites and subsequent precipitation quantities reaching the surface during events with similar meteorology. The goal of this study is to use precipitation chemistry information to gain a better understanding of the potential sources of INP in the south-central Sierra Nevada, where cloud-aerosol-precipitation interactions are under-studied and where mixed-phase orographic clouds represent a key element in the generation of precipitation and thus the water supply in California.

  3. Present importance of coffe production in some coffe grower communities and indian comunities in the Sierra Nevada de Santa Marta Importancia actual de la caficultora en algunas comunidades campesinas e indígenas de la Sierra Nevada de Santa Marta

    Directory of Open Access Journals (Sweden)

    Herrera Rojas Gilberto

    1993-12-01

    Full Text Available Coffe production followed by coffe growers and indian groups in the Sierra Nevada de Santa Marta, shows several differences regarding economical rationalityandtechnology. Coffe plays avery important role inthe economy and life quality ofthegrowers and indians. Traditional technology is generalized and has slowed down the deterioration of the Sierra, although life quality is very low.
    La caficultura que practican los campesinos y los grupos indlgenas de la Sierra Nevada de Santa Marta, tiene notables diferencias, tanto en la racionalidad económica, como en la lógica con la cual son atendidos los cultivos. El café juega un
    papel predominante en el sostenimiento de la economla
    y en la calidad de la vida de campecinos e indlgenas. La tecnologla tradicional, cuyo uso es generalizado, ha demorado el deterioro de ese inmenso maciso, aunuqe la calidad de la vida es bastante baja.

  4. GPS Imaging suggests links between climate, magmatism, seismicity, and tectonics in the Sierra Nevada-Long Valley Caldera-Walker Lane system, western United States

    Science.gov (United States)

    Hammond, W. C.; Blewitt, G.; Kreemer, C.; Smith, K.

    2017-12-01

    The Walker Lane is a region of complex active crustal transtension in the western Great Basin of the western United States, accommodating about 20% of the 50 mm/yr relative motion between the Pacific and North American plates. The Long Valley caldera lies in the central Walker Lane in eastern California, adjacent to the eastern boundary of the Sierra Nevada/Great Valley microplate, and experiences intermittent inflation, uplift, and volcanic unrest from the magma chamber that resides at middle crustal depths. Normal and transform faults accommodating regional tectonic transtension pass by and through the caldera, complicating the interpretation of the GPS-measured strain rate field, estimates of fault slip rates, and seismic hazard. Several dozen continuously recording GPS stations measure strain and uplift in the area with mm precision. They observe that the most recent episode of uplift at Long Valley began in mid-2011, continuing until late 2016, raising the surface by 100 mm in 6 years. The timing of the initiation of uplift coincides with the beginning of severe drought in California. Furthermore, the timing of a recent pause in uplift coincides with the very wet 2016-2017 winter, which saw approximately double normal snow pack. In prior studies, we showed that the timing of changes in geodetically measured uplift rate of the Sierra Nevada coincides with the timing of drought conditions in California, suggesting a link between hydrological loading and Sierra Nevada elevation. Here we take the analysis three steps further to show that changes in Sierra Nevada uplift rate coincide in time with 1) enhanced inflation at the Long Valley caldera, 2) shifts in the patterns and rates of horizontal tensor strain rate, and 3) seismicity patterns in the central Walker Lane. We use GPS solutions from the Nevada Geodetic Laboratory and the new GPS Imaging technique to produce robust animations of the time variable strain and uplift fields. The goals of this work are to

  5. Rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada

    Science.gov (United States)

    Rood, Dylan H.; Burbank, Douglas W.; Herman, Scott W.; Bogue, Scott

    2011-10-01

    We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. Samples from the Upper Miocene (˜9 Ma) Eureka Valley Tuff suggest clockwise vertical-axis block rotations between NE-striking left-lateral faults in the Bridgeport and Mono Basins. Results in the Bodie Hills suggest clockwise rotations (R ± ΔR, 95% confidence limits) of 74 ± 8° since Early to Middle Miocene (˜12-20 Ma), 42 ± 11° since Late Miocene (˜8-9 Ma), and 14 ± 10° since Pliocene (˜3 Ma) time with no detectable northward translation. The data are compatible with a relatively steady rotation rate of 5 ± 2° Ma-1 (2σ) since the Middle Miocene over the three examined timescales. The average rotation rates have probably not varied by more than a factor of two over time spans equal to half of the total time interval. Our paleomagnetic data suggest that block rotations in the region of the Mina Deflection began prior to Late Miocene time (˜9 Ma), and perhaps since the Middle Miocene if rotation rates were relatively constant. Block rotation in the Bodie Hills is similar in age and long-term average rate to rotations in the Transverse Ranges of southern California associated with early transtensional dextral shear deformation. We speculate that the age of rotations in the Bodie Hills indicates dextral shear and strain accommodation within the central Walker Lane Belt resulting from coupling of the Pacific and North America plates.

  6. Examining the Relationship Between Edaphic Variables and the Rooting System of Abies concolor in the southern Sierra Nevada

    Science.gov (United States)

    Wilson, A.; Jackson, R. B.; Tumber-Davila, S. J.

    2017-12-01

    An increase in the frequency and severity of droughts has been associated with the changing climate. These events have the potential to alter the composition and biogeography of forests, as well as increase tree mortality related to climate-induced stress. Already, an increase in tree mortality has been observed throughout the US. The recent drought in California led to millions of tree mortalities in the southern Sierra Nevada alone. In order to assess the potential impacts of these events on forest systems, it is imperative to understand what factors contribute to tree mortality. As plants become water-stressed, they may invest carbon more heavily belowground to reach a bigger pool of water, but their ability to adapt may be limited by the characteristics of the soil. In the Southern Sierra Critical Zone Observatory, a high tree mortality zone, we have selected both dead and living trees to examine the factors that contribute to root zone variability and belowground biomass investment by individual plants. A series of 15 cores surrounding the tree were taken to collect root and soil samples. These were then used to compare belowground rooting distributions with soil characteristics (texture, water holding capacity, pH, electric conductivity). Abies concolor is heavily affected by drought-induced mortality, therefore the rooting systems of dead Abies concolor trees were examined to determine the relationship between their rooting systems and environmental conditions. Examining the relationship between soil characteristics and rooting systems of trees may shed light on the plasticity of rooting systems and how trees adapt based on the characteristics of its environment. A better understanding of the factors that contribute to tree mortality can improve our ability to predict how forest systems may be impacted by climate-induced stress. Key words: Root systems, soil characteristics, drought, adaptation, terrestrial carbon, forest ecology

  7. Using wireless sensor networks to improve understanding of rain-on-snow events across the Sierra Nevada

    Science.gov (United States)

    Maurer, T.; Avanzi, F.; Oroza, C.; Malek, S. A.; Glaser, S. D.; Bales, R. C.; Conklin, M. H.

    2017-12-01

    We use data gathered from Wireless Sensor Networks (WSNs) between 2008 and 2017 to investigate the temporal/spatial patterns of rain-on-snow events in three river basins of California's Sierra Nevada. Rain-on-snow transitions occur across a broad elevation range (several hundred meters), both between storms and within a given storm, creating an opportunity to use spatially and temporally dense data to forecast and study them. WSNs collect snow depth; meteorological data; and soil moisture and temperature data across relatively dense sensor clusters. Ten to twelve measurement nodes per cluster are placed across 1-km2 areas in locations representative of snow patterns at larger scales. Combining precipitation and snow data from snow-pillow and climate stations with an estimation of dew-point temperature from WSNs, we determine the frequency, timing, and geographic extent of rain-on-snow events. We compare these results to WSN data to evaluate the impact of rain-on-snow events on snowpack energy balance, density, and depth as well as on soil moisture. Rain-on-snow events are compared to dry warm-weather days to identify the relative importance of rain and radiation as the primary energy input to the snowpack for snowmelt generation. An intercomparison of rain-on-snow events for the WSNs in the Feather, American, and Kings River basins captures the behavior across a 2° latitudinal range of the Sierra Nevada. Rain-on-snow events are potentially a more important streamflow generation mechanism in the lower-elevation Feather River basin. Snowmelt response to rain-on-snow events changes throughout the wet season, with later events resulting in more melt due to snow isothermal conditions, coarser grain size, and more-homogeneous snow stratigraphy. Regardless of snowmelt response, rain-on-snow events tend to result in decreasing snow depth and a corresponding increase in snow density. Our results demonstrate that strategically placed WSNs can provide the necessary data at

  8. Through the Looking Glass: Droughtorama to Snowpocalypse in the Sierra Nevada as studied with the NASA Airborne Snow Observatory

    Science.gov (United States)

    Painter, T. H.; Bormann, K.; Deems, J. S.; Hedrick, A. R.; Marks, D. G.; Skiles, M.; Stock, G. M.

    2017-12-01

    Across the last five years, the Sierra Nevada has seen increasing drought and then an abrupt return to a top five snowpack. Fortunately, the NASA Airborne Snow Observatory has been flying the Central Sierra Nevada since the spring of 2013, quantifying critical mountain basins' snow water equivalent and snow albedo. The huge variation of snowpack years captured by the NASA ASO is of enormous benefit to water cycle science, ecosystem science, and water management utilization of ASO data and its modeling. It allows a much broader understanding of mountain basin snow season cases for understanding snowmelt runoff, snow/rain mixes, snowfall distribution, evapotranspiration, soil moisture, and glacier mass balance. For water management, trust in empirical and physically-based modeling from the ASO data for application anywhere in the range of snow years is greatly improved by having consistency in that modeling with the span of years ASO has characterized. The NASA ASO was designed to characterize mountain snowpack and fill this void in water cycle science. Our original conversations with partner California Department of Water Resources in 2011 focused on the utility of ASO for flood risk mitigation, given the large snowfall of that year. However, from 2012 through 2016, California snowpacks expressed horrible drought, reaching the nadir in 2015 with the lowest snowpack on record. The 2016 snowpack was nearly normal according to snow pillows and snow courses (ASO's record is too short to define a `normal' year). However, 2017 had enormous snowfall in January and February, keeping snow pillows on track with the largest year on record, 1982-83. However, March backed off and the record year was lost. Still, accumulation was enormous. In parts of the San Joaquin basin, snow depths were > 30 m. The sum of near April 1 ASO total basin SWE for 2013 through 2016 in the Tuolumne Basin was only 92% of the near April 1, 2017 acquisition. In addition to the large accumulation of

  9. Paleozoic subduction complex and Paleozoic-Mesozoic island-arc volcano-plutonic assemblages in the northern Sierra terrane

    Science.gov (United States)

    Hanson, Richard E.; Girty, Gary H.; Harwood, David S.; Schweickert, Richard A.

    2000-01-01

    This field trip provides an overview of the stratigraphic and structural evolution of the northern Sierra terrane, which forms a significant part of the wall rocks on the western side of the later Mesozoic Sierra Nevada batholith in California. The terrane consists of a pre-Late Devonian subduction complex (Shoo Fly Complex) overlain by submarine arc-related deposits that record the evolution of three separate island-arc systems in the Late Sevonian-Early Mississippian, Permian, and Late Triassic-Jurassic. The two Paleozoic are packages and the underlying Shoo Fly Complex have an important bearing on plate-tectonic processes affecting the convergent margin outboard of the Paleozoic Cordilleran miogeocline, although their original paleogeographic relations to North America are controversial. The third arc package represents an overlap assemblage that ties the terrane to North America by the Late Triassic and helps constrain the nature and timing of Mesozoic orogenesis. Several of the field-trip stops examine the record of pre-Late Devonian subduction contained in the Shoo Fly Complex, as well as the paleovolcanology of the overlying Devonian to Jurassic arc rocks. Excellent glaciated exposures provide the opportunity to study a cross section through a tilted Devonian volcano-plutonic association. Additional stops focus on plutonic rocks emplaced during the Middle Jurassic arc magmatism in the terrane, and during the main pulse of Cretaceous magmatism in the Sierra Nevada batholith to the east.

  10. PLANTAS MEDICINALES USADAS POR LOS COGUI EN EL RÍO PALOMINO, SIERRA NEVADA DE SANTA MARTA (COLOMBIA

    Directory of Open Access Journals (Sweden)

    EDUINO CARBONÓ-DELAHOZ

    2013-12-01

    Full Text Available Con el propósito de registrar conocimientos tradicionales sobre plantas medicinales entre los Cogui o Kággaba en la cuenca del río Palomino, Sierra Nevada de Santa Marta (Colombia, se evaluó el uso de la flora con la aplicación de una técnica etnobotánica cuantitativa. Mediante entrevistas a mamos o sacerdotes-jefes, durante recorridos en áreas silvestres, cultivadas y huertos caseros en diferentes zonas climáticas de la cuenca, se obtuvo información de 189 especies utilizadas, incluidas en 162 géneros y 77 familias, así como el modo de uso y la forma de preparación para el tratamiento de enfermedades comunes. Las familias Asteraceae y Leguminosae registraron el mayor número de especies útiles. La evaluación con el índice de importancia relativa (IR permitió establecer que Ladenbergia moritziana (Rubiaceae, Stevia lucida (Asteraceae, Aniba sp. (Lauraceae, Erechtites hieracifolia (Asteraceae y Carex sp. (Cyperaceae son las especies con mayores valores de importancia. El 89 % de las plantas utilizadas es obtenido de espacios silvestres, lo que sugiere un conocimiento amplio de la diversidad vegetal local y el ejercicio de una práctica etnomédica.

  11. Processes affectin the chemistry of waters passing through a high elevator Sierra Nevada watershed. [U. S. A

    Energy Technology Data Exchange (ETDEWEB)

    Nodvin, S.C.

    1987-01-01

    The Eastern Brook Lakes watershed is located in the Sierra Nevada Mountains of California and spans and elevational range from 3060 to 3780 m. Changes in stream and lake chemistries along spatial and temporal flowpaths demonstrate that both terrestrial and aquatic processes were important in regulating surface water chemistries within the 250 ha watershed. Streams generally showed increasing pH, alkalinity, and conductance values with decreasing elevation. Large changes in stream chemistries occurred over short distances at locations such as alpine meadows. During the spring, stream alkalinities and conductance values decreased while stream pH values increased with time. pH values reached their maximim in June when alkalinity and conductance values were at their minimum values. Internal lake processes strongly influenced the chemistry of Upper Eastern Brook Lake. During spring and summer, lake waters exhibited near-neutral pH, low conductance (10-12 ..mu..S/cm), low alkalinity (100-120 ..mu..Eq/L), and undetectable ammonium. Under the ice, major changes in lake chemistry occurred associated with oxygen depletion in the hypolimnion. pH values decreased with time towards a minimum of 6.3 at 6 m depth. Other parameters increased w time and depth under the ice, reaching maximum values as follows: conductance > 80 ..mu..S/cm/sup -1/ Gran's alkalinity > 370 ..mu..Eq/L/sup -1/, and ammonium > 50 /sup m/u/sup E/q/L/sup -1/. 5 figures, 10 references.

  12. Distribution and stability of potential salmonid spawning gravels in steep boulder-bed streams of the eastern Sierra Nevada

    International Nuclear Information System (INIS)

    Kondolf, G.M.; Cada, G.F.; Sale, M.J.; Felando, T.

    1991-01-01

    Interest in small hydroelectric development (< 5 MW) has recently focused attention on steep streams and the resident trout populations they contain. High-gradient boulder-bed streams have been the sites of relatively few studies of salmonid spawning habitat, although they have geomorphic and hydraulic characteristics - and therefore gravel distributions - that are quite different from the more commonly described lower-gradient channels. The authors documented gravel distribution in seven high-gradient stream reaches in the eastern Sierra Nevada. Gravels occurred only in locations characterized by relatively low shear stress; they formed small pockets in sites of low divergence and larger deposits upstream of natural hydraulic controls. In 1986 (a wet year), all tracer gravels placed in gravel pockets at nine sites on four streams were completely swept away, and substantial scour, fill, and other channel changes occurred at many sites. In 1987 (a dry year), tracer gravels and the channel cross sections were generally stable. Periodic mobility of gravel may explain why brown trout Salmo trutta are more abundant than rainbow trout Oncorhychus mykiss in the study reaches, where high flows occur every May and June during snowmelt. Brown trout are fall spawners, and their fry emerge long before the high snowmelt flows, whereas rainbow trout are spring spawners whose eggs are in the gravel, and thus vulnerable to scour, during snowmelt flows

  13. Pre-eruptive conditions of the ~31 ka rhyolitic magma of Tlaloc volcano, Sierra Nevada Volcanic Range, Central Mexico

    Science.gov (United States)

    Macias, J.; Arce, J.; Rueda, H.; Gardner, J.

    2008-12-01

    Tlaloc volcano is located at the northern tip of the Sierra Nevada Volcanic Range in Central Mexico. This Pleistocene to Recent volcanic range consists from north to south of Tlaloc-Telapón-Teyotl-Iztaccíhuatl-and- Popocatépetl volcanoes. While andesitic to barely dacitic volcanism dominates the southern part of the range (i.e. Popocatépetl and Iztaccíhuatl); dacitic and rare rhyolithic volcanism (i.e. Telapón, Tlaloc) dominates the northern end. The known locus of rhyolitic magmatism took place at Tlaloc volcano with a Plinian-Subplinian eruption that occurred 31 ka ago. The eruption emplaced the so-called multilayered fallout and pumiceous pyroclastic flows (~2 km3 DRE). The deposit consists of 95% vol. of juvenile particles (pumice + crystals) and minor altered lithics 5% vol. The mineral association of the pumice fragments (74-76 % wt. SiO2) consists of quartz + plagioclase + sanidine + biotite and rare oxides set in a glassy groundmass with voids. Melt inclusions in quartz phenocrysts suggest that prior to the eruption the rhyolitic contain ~7% of H2O and Nevado de Toluca volcano (~6 km) some 50 km to the southwest.

  14. Application of Wildfire Risk Assessment Results to Wildfire Response Planning in the Southern Sierra Nevada, California, USA

    Directory of Open Access Journals (Sweden)

    Matthew P. Thompson

    2016-03-01

    Full Text Available How wildfires are managed is a key determinant of long-term socioecological resiliency and the ability to live with fire. Safe and effective response to fire requires effective pre-fire planning, which is the main focus of this paper. We review general principles of effective federal fire management planning in the U.S., and introduce a framework for incident response planning consistent with these principles. We contextualize this framework in relation to a wildland fire management continuum based on federal fire management policy in the U.S. The framework leverages recent advancements in spatial wildfire risk assessment—notably the joint concepts of in situ risk and source risk—and integrates assessment results with additional geospatial information to develop and map strategic response zones. We operationalize this framework in a geographic information system (GIS environment based on landscape attributes relevant to fire operations, and define Potential wildland fire Operational Delineations (PODs as the spatial unit of analysis for strategic response. Using results from a recent risk assessment performed on several National Forests in the Southern Sierra Nevada area of California, USA, we illustrate how POD-level summaries of risk metrics can reduce uncertainty surrounding potential losses and benefits given large fire occurrence, and lend themselves naturally to design of fire and fuel management strategies. To conclude we identify gaps, limitations, and uncertainties, and prioritize future work to support safe and effective incident response.

  15. Radiation balances of melting snow covers at an open site in the Central Sierra Nevada, California

    International Nuclear Information System (INIS)

    Aguado, E.

    1985-01-01

    The radiation balances of melting snow packs for three seasons at an open site at the Central Sierra Snow Laboratory near Soda Springs, California were examined. The snow covers were examples of below-normal, near-normal and much-above-normal water equivalents. Two of the snow covers melted under generally clear skies in late spring while the other melted under cloudier conditions and at a time when less extraterrestrial radiation was available. Moreover, the snow covers were of very different densities, thereby allowing examination of a possible relationship between that characteristic and albedo. No such relationship was observed. Despite the dissimilarities in the conditions under which melt occurred, the disposition of solar radiation was similar for the three melt seasons. Albedos and their rates of decline through the melt season were similar for the three seasons. Absorbed solar radiation and a cloudiness index were useful predictors for daily net radiation, accounting for 71% of the total variance. (author)

  16. A tale of 10 plutons - Revisited: Age of granitic rocks in the White Mountains, California and Nevada

    Science.gov (United States)

    McKee, E.H.; Conrad, J.E.

    1996-01-01

    40Ar/39Ar incremental heating analysis and conventional K-Ar age determinations on plutonic rocks of the White Mountains define two stages of magmatic emplacement: Late Cretaceous, between ca. 90 Ma and 75 Ma, and Middle-Late Jurassic, between ca. 180 and 140 Ma. The Jurassic stage can be divided into two substages, 180-165 Ma and 150-140 Ma. Thermal effects of the younger plutons on the older granitoids partially to completely reset ages, making it difficult to determine the age of emplacement and cooling of several of the plutons even by 40Ar/39Ar incremental heating analyses. New data together with published ages and regional geochronological synthesis of the Sierra Nevada batholith indicate that regions within the batholith have coherent periods or episodes of magmatic activity. In the White Mountains and Sierra Nevada directly to the west there was little or no activity in Early Jurassic and Early Cretaceous time; magmatism took place during relatively short intervals of 15 m.y. or less in the Middle and Late Jurassic and Late Cretaceous periods. The new K-Ar and 40Ar/39Ar analyses of granitoids from the White Mountains help, but do not completely clarify the complex history of emplacement, cooling, and reheating of the batholith.

  17. Using ecological forecasting of future vegetation transition and fire frequency change in the Sierra Nevada to assess fire management strategies

    Science.gov (United States)

    Thorne, J. H.; Schwartz, M. W.; Holguin, A. J.; Moritz, M.; Batllori, E.; Folger, K.; Nydick, K.

    2013-12-01

    Ecological systems may respond in complex manners as climate change progresses. Among the responses, site-level climate conditions may cause a shift in vegetation due to the physiological tolerances of plant species, and the fire return interval may change. Natural resource managers challenged with maintaining ecosystem health need a way to forecast how these processes may affect every location, in order to determine appropriate management actions and prioritize locations for interventions. We integrated climate change-driven vegetation type transitions with projected change in fire frequency for 45,203 km2 of the southern Sierra Nevada, California, containing over 10 land management agencies as well as private lands. This Magnitude of Change (MOC) approach involves classing vegetation types in current time according to their climate envelopes, and identifying which sites will in the future have climates beyond what that vegetation currently occurs in. Independently, fire models are used to determine the change in fire frequency for each site. We examined 82 vegetation types with >50 grid cell occurrences. We found iconic resources such as the giant sequoia, lower slope oak woodlands, and high elevation conifer forests are projected as highly vulnerable by models that project a warmer drier future, but not as much by models that project a warmer future that is not drier than current conditions. Further, there were strongly divergent vulnerabilities of these forest types across land ownership (National Parks versus US Forest Service lands), and by GCM. For example, of 50 giant sequoia (Sequoiadendron giganteum) groves and complexes, all but 3 (on Sierra National Forest) were in the 2 highest levels of risk of climate and fire under the GFDL A2 projection, while 15 groves with low-to-moderate risk were found on both the National Parks and National Forests 18 in the 2 under PCM A2. Landscape projections of potential MOC suggest that the region is likely to experience

  18. Simulating high spatial resolution high severity burned area in Sierra Nevada forests for California Spotted Owl habitat climate change risk assessment and management.

    Science.gov (United States)

    Keyser, A.; Westerling, A. L.; Jones, G.; Peery, M. Z.

    2017-12-01

    Sierra Nevada forests have experienced an increase in very large fires with significant areas of high burn severity, such as the Rim (2013) and King (2014) fires, that have impacted habitat of endangered species such as the California spotted owl. In order to support land manager forest management planning and risk assessment activities, we used historical wildfire histories from the Monitoring Trends in Burn Severity project and gridded hydroclimate and land surface characteristics data to develope statistical models to simulate the frequency, location and extent of high severity burned area in Sierra Nevada forest wildfires as functions of climate and land surface characteristics. We define high severity here as BA90 area: the area comprising patches with ninety percent or more basal area killed within a larger fire. We developed a system of statistical models to characterize the probability of large fire occurrence, the probability of significant BA90 area present given a large fire, and the total extent of BA90 area in a fire on a 1/16 degree lat/lon grid over the Sierra Nevada. Repeated draws from binomial and generalized pareto distributions using these probabilities generated a library of simulated histories of high severity fire for a range of near (50 yr) future climate and fuels management scenarios. Fuels management scenarios were provided by USFS Region 5. Simulated BA90 area was then downscaled to 30 m resolution using a statistical model we developed using Random Forest techniques to estimate the probability of adjacent 30m pixels burning with ninety percent basal kill as a function of fire size and vegetation and topographic features. The result is a library of simulated high resolution maps of BA90 burned areas for a range of climate and fuels management scenarios with which we estimated conditional probabilities of owl nesting sites being impacted by high severity wildfire.

  19. Preface to anthropogenic fluvial sedimentation: Centennial celebration of G.K. Gilbert's Hydraulic-Mining Débris in the Sierra Nevada

    Science.gov (United States)

    James, L. Allan; Phillips, Jonathan D.; Lecce, Scott A.

    2017-10-01

    This special issue celebrates the centennial of the publication of G.K. Gilbert's (1917) monograph, Hydraulic-Mining Débris in the Sierra Nevada, U.S. Geological Survey Professional Paper 105 (PP105). Reasons to celebrate PP105 are manifold. It was the last of four classic monographs that Gilbert wrote in a career that spanned five decades. The monograph, PP105, introduced several important concepts and provided an integrated view of watersheds that was uncommon in its day. It also provided an extreme, lucid example of anthropogenic changes and legacy sediment and how to approach such large-scale phenomena from an objective, quantitative basis.

  20. Some attempts at a geological explanation for the origin of the Sierra Nevada de Santa Marta in the Nineteenth Century: the naturalists Joaquin Acosta and Jorge Isaacs

    International Nuclear Information System (INIS)

    Castro Lopez, Pablo Antonio; Cardona Molina, Agustin

    2010-01-01

    The Sierra Nevada de Santa Marta, located in the northernmost part of Colombia, has been an object of scientific inquiry since at least the XIXth century, among other things because of its isolated character in relation to the Andean mountain chain. In this article we present some contributions to the knowledge of its origin and geological framework made by Joaquin Acosta (1800-1852) and Jorge Isaacs (1837-1895). Furthermore we establish a possible theoretical and conceptual relationship between these authors and some important European geologists and naturalists in the XIXth century, in the context of a history of ideas pertaining to orogenesis in Colombia.

  1. Evolution of the persistence of snow over Sierra Nevada Mountain (southern, Spain) in the last 55 years

    Science.gov (United States)

    Pimentel, Rafael; José Pérez-Palazón, María; Herrero, Javier; José Polo, María

    2016-04-01

    Snow plays a crucial role in mountainous areas, not only as water resources for human supply, irrigation and energy production, but also for the ecosystem, flora and fauna, over these areas. Sierra Nevada Mountains, southern Spain, constitutes a rich reservoir of endemic wildlife species, and it is considered the most important center of biodiversity in the wester Mediterranean region. The highest regions of the range were declared UNESCO Biosphere Reserve, Natural and National Parks. Climate trends over the last decades put a lot of pressure on both snowfall occurrence and snow persistence; this poses a risk for biodiversity and has led to its inclusion in the Global Change Observatory Network. This work quantifies the evolution of the persistence of snow over the Sierra Nevada area during the last fifty-five years (1960-2015) as a basis to assess the vulnerability of its ecosystem services. For this, the spatial distribution of the annual number of days with snow, SDS, was analyzed over a study area of 4583 km2 (140-3479 m.a.s.l.), which comprises the head of the five basins in these mountains. The following indicator variables were studied over the whole area and each one of the five head regions identified: 1) the trend of SDS; 2) the annual area where SDS exceeded selected percentiles in its distribution; and 3) the annual minimum altitude where SDS exceeded those percentiles. SDS was obtained during the study period by means of the snow module in WiMMed (Watershed Integrated Model in Mediterranean Environment), a physically-based hydrological model developed, calibrated and validated in the area; the model is based on an energy-mass balance over the snowpack that is spatially distributed through the use of depletion curves, and is operational at hourly and daily scales. A general decreasing trend of SDS (0.25 days year-1) was found over the whole study area for the study period. This value is higher in the more humid basins (0.45 and 0.41 days year-1) than in

  2. Incorporating Problem-Based Learning Into A Petrology Course Through A Research Project In The Local Northern Sierra Nevada

    Science.gov (United States)

    Aird, H. M.

    2016-12-01

    A research project into the local petrology was integrated into the Spring 2016 Petrology and Optical Mineralogy course at California State University, Chico. This is a required majors course, typically taken during spring of the junior year, with an enrollment of 10-20 students. Since the labs for this course have a strong focus on petrography, a research project was introduced to give students experience in using a multi-faceted approach to investigate a problem. In many cases, this is their first taste of research. During the first week of the Spring 2016 class, students were introduced to the research question: In the broader context of Californian tectonic history, are the Bucks Lake and Grizzly plutons of the northern Sierra Nevada petrogenetically related? With faculty guidance over the course of the semester, students carried out fieldwork and sampling, lithologic description, selection of the best samples for further analysis, thin section production, petrographic description, and analysis and interpretation of published geochemical data. Research activities were strategically scheduled within the course framework such that students were academically prepared to carry out each task. Each student was responsible for generating all the data for one sample, and data were then collated as a class, so students wrote their individual final reports using all the data collected by the class. Careful scaffolding of writing assignments throughout the semester guided students through the preparation of an academic-style scientific report, while allowing for repeated feedback on their writing style and content. In mid-May, the class presented a group poster at the College of Natural Sciences annual poster symposium, and were awarded `Best Student Class Project' by the judges. Anecdotal student feedback indicated they highly valued the research experience and some were inspired to pursue individual undergraduate research projects under faculty supervision.

  3. Does prescribed fire promote resistance to drought in low elevation forests of the Sierra Nevada, California, USA?

    Science.gov (United States)

    van Mantgem, Phillip J.; Caprio, Anthony C.; Stephenson, Nathan L.; Das, Adrian J.

    2016-01-01

    Prescribed fire is a primary tool used to restore western forests following more than a century of fire exclusion, reducing fire hazard by removing dead and live fuels (small trees and shrubs).  It is commonly assumed that the reduced forest density following prescribed fire also reduces competition for resources among the remaining trees, so that the remaining trees are more resistant (more likely to survive) in the face of additional stressors, such as drought.  Yet this proposition remains largely untested, so that managers do not have the basic information to evaluate whether prescribed fire may help forests adapt to a future of more frequent and severe drought.During the third year of drought, in 2014, we surveyed 9950 trees in 38 burned and 18 unburned mixed conifer forest plots at low elevation (accounting for differences in individual tree diameter, common conifer species found in the burned plots had significantly reduced probability of mortality compared to unburned plots during the drought.  Stand density (stems ha-1) was significantly lower in burned versus unburned sites, supporting the idea that reduced competition may be responsible for the differential drought mortality response.  At the time of writing, we are not sure if burned stands will maintain lower tree mortality probabilities in the face of the continued, severe drought of 2015.  Future work should aim to better identify drought response mechanisms and how these may vary across other forest types and regions, particularly in other areas experiencing severe drought in the Sierra Nevada and on the Colorado Plateau.

  4. Sierra Nevada, California, U.S.A., Snow Algae: Snow albedo changes, algal-bacterial interrelationships and ultraviolet radiation effects

    International Nuclear Information System (INIS)

    Thomas, W.H.; Duval, B.

    1995-01-01

    In the Tioga Pass area (upper LeeVining Creek watershed) of the Sierra Nevada (California), snow algae were prevalent in the early summers of 1993 and 1994. Significant negative correlations were found between snow water content. However, red snow caused by algal blooms did not decrease mean albedos in representative snowfields. This was due to algal patchiness; mean albedos would not decrease over the whole water catchment basin; and water supplies would not be affected by the presence of algae. Albedo was also reduced by dirt on the snow, and wind-blown dirt may provide a source of allochthonous organic matter for snow bacteria. However, several observations emphasize the importance of an autochthonous source for bacterial nutrition. Bacterial abundances and production rates were higher in red snow containing algae than in noncolored snow. Bacterial production was about two orders-of-magnitude lower than photosynthetic algal production. Bacteria were also sometimes attached to algal cells. In experiments where snow algae were contained in UV-transmitting quartz tubes, ultraviolet radiation inhibited red snow (collected form open, sunlit areas) photosynthesis about 25%, while green snow (collected from forested, shady locations) photosynthesis was inhibited by 85%. Methanol extracts of red snow algae had greater absorbances in blue and UV spectral regions than did algae from green snow. These differences in UV responses and spectra may be due to habitat (sun vs shade) differences, or may be genetic, since different species were found in the two snow types. However, both habitat and genetic mechanisms may be operating together to cause these differences. 53 refs., 5 figs., 5 tabs

  5. Effects of evapotranspiration heterogeneity on catchment water balance in the Southern Sierra Nevada of California

    Science.gov (United States)

    Kerkez, B.; Kelly, A. E.; Lucas, R. G.; Son, K.; Glaser, S. D.; Bales, R. C.

    2011-12-01

    Heterogeneity of Evapotranspiration (ET) is the result of poorly understood interactions between climate, topography, vegetation and soil. Accurate predictions of ET, and thus improved water balance estimates, hinge directly upon an improved understanding of the processes that drive ET across a wide spatio-temporal range. Recent warming trends in the Western US are shifting precipitation toward more rain-dominated patterns, significantly increasing vegetation water stress in historically snow-dominated regimes due to reduced soil moisture and increased vapor deficit during warm summer months. We investigate dominant controls that govern ET variability in a highly instrumented 1km2 mountain catchment at the Southern Sierra Critical Zone Observatory, co-located in the Kings River Experimental Watershed. Various ET estimates are derived from a number of measurement approaches: an eddy flux covariance tower, ET chambers, stream flumes, groundwater monitoring wells, matric potential sensors, as well as data from a distributed wireless sensor network with over 300 sensors. Combined with precipitation data, and high-density distributed soil moisture and snowdepth readings, the ET estimates are utilized to reconstruct the overall catchment water balance. We also apply the Regional Hydro-Ecologic Simulation System (RHESSys), a physically based, spatially distributed hydrologic model, to estimate water balance components. The model predictions are compared with the water budget calculated from field data, and used to identify the key variables controlling spatial and temporal patterns of ET at multiple scales. Initial results show that ET estimates are scale-, and vegetation-dependent, with significant ET variability between vegetation types and physiographic parameters such as elevation, slope, and aspect. In mixed conifer forests terrain, ET is more dependent on soil moisture, while in the meadows, where the soil is generally saturated for the duration of the growing

  6. New Geologic Map and Structural Cross Sections of the Death Valley Extended Terrain (southern Sierra Nevada, California to Spring Mountains, Nevada): Toward 3D Kinematic Reconstructions

    Science.gov (United States)

    Lutz, B. M.; Axen, G. J.; Phillips, F. M.

    2017-12-01

    Tectonic reconstructions for the Death Valley extended terrain (S. Sierra Nevada to Spring Mountains) have evolved to include a growing number of offset markers for strike-slip fault systems but are mainly map view (2D) and do not incorporate a wealth of additional constraints. We present a new 1:300,000 digital geologic map and structural cross sections, which provide a geometric framework for stepwise 3D reconstructions of Late Cenozoic extension and transtension. 3D models will decipher complex relationships between strike-slip, normal, and detachment faults and their role in accommodating large magnitude extension/rigid block rotation. Fault coordination is key to understanding how extensional systems and transform margins evolve with changing boundary conditions. 3D geometric and kinematic analysis adds key strain compatibility unavailable in 2D reconstructions. The stratigraphic framework of Fridrich and Thompson (2011) is applied to rocks outside of Death Valley. Cenozoic basin deposits are grouped into 6 assemblages differentiated by age, provenance, and bounding unconformities, which reflect Pacific-North American plate boundary events. Pre-Cenozoic rocks are grouped for utility: for example, Cararra Formation equivalents are grouped because they form a Cordilleran thrust decollement zone. Offset markers are summarized in the associated tectonic map. Other constraints include fault geometries and slip rates, age, geometry and provenance of Cenozoic basins, gravity, cooling histories of footwalls, and limited seismic/well data. Cross sections were constructed parallel to net-transport directions of fault blocks. Surface fault geometries were compiled from previous mapping and projected to depth using seismic/gravity data. Cooling histories of footwalls guided geometric interpretation of uplifted detachment footwalls. Mesh surfaces will be generated from 2D section lines to create a framework for stepwise 3D reconstruction of extension and transtension in

  7. The Eastern delta-fan deposits on the Granada Basin as tectonic indicators of the Sierra Nevada uplift (Betic Cordillera, South Spain)

    Science.gov (United States)

    Roldán, Francisco Javier; Azañon, Jose Miguel; Mateos, Rosa Maria

    2014-05-01

    A geological mapping in detail of the Eastern sector of the Granada Basin (South Spain) reveals two different groups of Gilbert delta-fans related to the Sierra Nevada uplift. The first group, in the southern part and with a surface of 6 km2, has three major coarsening-upward sequences. They are composed of very coarse deposits, those of conglomerates, sands and silts. Progradational strata units to the basin have been observed. The dominantly fluvial facies association has locally developed shallow marine foreset deposits (partially with reef colonization) as well as topset red soils (Dabrio, et al., 1978; Braga et a., 1990; García-García, et al., 1999) . All the sequences are discordant over marine facies (calcarenites) dated over 8,26 Ma (Late Tortonian). The second group, in the northern part and with an extension of 12 km2, has similar characteristics, but some of the boulders have ostreids and lamellibranchs species which reveal their former position in a previous marine environment. The Sierra Nevada uplift caused the remobilization of these boulders, being transported by debris-flow inside the delta-fan bodies (García-García, et al., 2006). The dating of ostreids shells with Sr techniques reveals ages over 7,13, 6,61 and 5,45 Ma, from the lower to the upper delta-fan deposits, which are related to the three main sequences observed and with three major tectonic pulses during the Late Miocene. These interpretations are in agreement with apatite fision-track studies carried out in some boulders of these coarse delta-fan deposits (Clark and Dempster, 2013). They reveal a detailed record of Neogene denudation from the Sierra Nevada basement and with uplift periods between 5,45Ma- 2 Ma. The latest pulses affected the delta-fan sediments given rise to new fan systems in the Granada Basin (Alhambra Formation). The thoroughly study of the Miocene delta-fan sediments allows us to conclude that they were related to a sin-sedimentary tectonic activity linked to the

  8. Next Generation Snow Cover Mapping: Can Future Hyperspectral Satellite Spectrometer Systems Improve Subpixel Snow-covered Area and Grain Size in the Sierra Nevada?

    Science.gov (United States)

    Hill, R.; Calvin, W. M.; Harpold, A.

    2017-12-01

    Mountain snow storage is the dominant source of water for humans and ecosystems in western North America. Consequently, the spatial distribution of snow-covered area is fundamental to both hydrological, ecological, and climate models. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data were collected along the entire Sierra Nevada mountain range extending from north of Lake Tahoe to south of Mt. Whitney during the 2015 and 2016 snow-covered season. The AVIRIS dataset used in this experiment consists of 224 contiguous spectral channels with wavelengths ranging 400-2500 nanometers at a 15-meter spatial pixel size. Data from the Sierras were acquired on four days: 2/24/15 during a very low snow year, 3/24/16 near maximum snow accumulation, and 5/12/16 and 5/18/16 during snow ablation and snow loss. Building on previous retrieval of subpixel snow-covered area algorithms that take into account varying grain size we present a model that analyzes multiple endmembers of varying snow grain size, vegetation, rock, and soil in segmented regions along the Sierra Nevada to determine snow-cover spatial extent, snow sub-pixel fraction, and approximate grain size. In addition, varying simulated models of the data will compare and contrast the retrieval of current snow products such as MODIS Snow-Covered Area and Grain Size (MODSCAG) and the Airborne Space Observatory (ASO). Specifically, does lower spatial resolution (MODIS), broader resolution bandwidth (MODIS), and limited spectral resolution (ASO) affect snow-cover area and grain size approximations? The implications of our findings will help refine snow mapping products for planned hyperspectral satellite spectrometer systems such as EnMAP (slated to launch in 2019), HISUI (planned for inclusion on the International Space Station in 2018), and HyspIRI (currently under consideration).

  9. [Reproduction of Joturus pichardi and Agonostomus monticola (Mugiliformes: Mugilidae) in rivers of the Sierra Nevada de Santa Marta, Colombia].

    Science.gov (United States)

    Eslava Eljaiek, Pedro; Díaz Vesga, Roy

    2011-12-01

    The freshwater mugilids Joturus pichardi and Agonostomus monticola, have been documented on ecological and distribution aspects, mainly for Central American populations, nevertheless, little information is available on their reproductive aspects, specifically in Colombian freshwater environments. Reproductive biology of the mugilids J. pichardi and A. monticola from Sierra Nevada de Santa Marta (SNSM) rivers was studied between July 2005 and December 2006. A total of 14 specimens of J. pichardi and 320 of A. monticola were collected. The reproductive biology was analyzed by means of: sexual proportion, gonadosomatic index, and mean size at maturity, fecundity and oocyte diameter. Additionally, a bioassay was carried out to evaluate the effect of salinity on spermatic motility and its possible relationship with the species' spawning area. These mugilids share habitats with similar ecological characteristics, in which strong currents; clear water and stony areas stand out. Gonadal maturity indicators and indirect evidence are presented to support the relationship between reproductive maturity and higher rainfall levels in the area (September, October and November), as well as the catadromous migration of J. pichardi and A. monticola. This last species females outnumbered males with a sex ratio of 2.3:1. Females mean size at maturity was 172mm of their total length (TL) and 108mm TL for males. Fecundity (F) was 23 925 +/- 4 581 eggs per gram of gonad, and was related to size by the equation F = 395.1TL(1.281); besides, the mean oocyte diameter was 362 +/- 40 microm. Considering the salinity effect on sperm motility in both species, results suggested that J. pichardi spawned in estuarine environments but the species did not migrate to fully marine environments; however, A. monticola withstood a broad range of salinity, suggesting a spawning from intermediate to total saline environments. Both species have high culturing potentials, considering that their feeding is

  10. Rb-Sr, K-Ar, and stable isotope evidence for the ages and sources of fluid components of gold-bearing quartz veins in the northern Sierra Nevada foothills metamorphic belt, California

    Science.gov (United States)

    Böhlke, John Karl; Kistler, R. W.

    1986-01-01

    Gold-bearing quartz veins occur in and near major fault zones in deformed oceanic and island-arc rocks west of the main outcrop of the Sierra Nevada composite batholith. Veins typically occupy minor reverse faults that crosscut blueschist to amphibolite-grade metamorphic rocks whose metamorphic ages range from early Paleozoic to Jurassic. Vein micas and carbonate-quartz-mica assemblages that formed by hydrothermal metasomatism of ultramafic wall rocks in the Alleghany, Grass Valley, Washington, and Mother Lode districts yield concordant K-Ar and Rb-Sr ages. The dated veins are significantly younger than prograde metamorphism, penetrative deformation, and accretion of their host rocks to the continental margin. New and previously published mineralization ages from 13 localities in the Sierra foothills range from about 140 to 110 m.y. ago, with mean and median between 120 and 115 m.y. The age relations suggest that mineralizing fluids were set in motion by deep magmatic activity related to the resumption of east-dipping subduction along the western margin of North America following the Late Jurassic Nevadan collision event.CO 2 -bearing fluids responsible for metasomatism and much of the vein mica, carbonate, albite, and quartz deposition in several northern mines were isotopically heavy (delta 18 O [asymp] 8-14ppm; delta D between about -10 and -50ppm) and do not resemble seawater, magmatic, or meteoric waters. Metasomatic and vein-filling mica, dolomite, magnesite, and quartz in altered ultramafic rocks generally formed from fluids with similar Sr and O isotope ratios at a given locality. Consistent quartz-mica delta 18 O fractionations (delta 18 O (sub Q-M) = 4.5-4.9ppm) from various localities imply uniform equilibration temperatures, probably between 300 degrees and 350 degrees C. On a local (mine) scale, fluids responsible for both carbonate alteration of mafic and ultramafic wall rocks and albitic alteration of felsic and pelitic rocks had similar Sr isotope

  11. Soil microbial abundance, activity and diversity response in two different altitude-adapted plant communities affected by wildfire in Sierra Nevada National Park (Granada, Spain)

    Science.gov (United States)

    Bárcenas-Moreno, Gema; Zavala, Lorena; Jordan, Antonio; Bååth, Erland; Mataix-Beneyto, Jorge

    2013-04-01

    Plant communities can play an important role in fire severity and post-fire ecosystem recovery due to their role as combustible and different plant-soil microorganisms interactions. Possible differences induced by plant and microorganisms response after fire could affect the general ecosystem short and long-term response and its sustainability. The main objective of this work was the evaluation of the effect of wildfire on soil microbial abundance, activity and diversity in two different plant communities associated to different altitudes in Sierra Nevada National Park (Granada, Spain). Samples were collected in two areas located on the Sierra Nevada Mountain between 1700 and 2000 m above sea level which were affected by a large wildfire in 2005. Two samplings were carried out 8 and 20 months after fire and samples were collected in both burned and unburned (control) zones in each plant community area. Area A is located at 1700m and it is formed by Quercus rotundifolia forest while area B is located at 2000 m altitude and is composed of alpine vegetation formed by creeping bearing shrubs. Microbial biomass measured by Fumigation-Extraction method followed the same trend in both areas showing slight and no significant differences between burned and unburned area during the study period while viable and cultivable bacteria abundance were markedly higher in fire affected samples than in the control ones in both samplings. Viable and cultivable filamentous fungi had different behavior depending of plant vegetation community studied showing no differences between burned and unburned area in area A while was significantly higher in burned samples than in the control ones in area B. Microbial activity monitoring with soil microbial respiration appears to had been affected immediately after fire since microbial respiration was lower in burned samples from area A than in unburned one only 8 months after fire and no significant differences were observed between burned and

  12. Estado poblacional del orden Plecoptera (Insecta en el Parque Nacional Sierra Nevada en Venezuela y sus implicaciones para planes de conservación

    Directory of Open Access Journals (Sweden)

    Maribet Gamboa

    2010-12-01

    Full Text Available La distribución longitudinal de las especies de plecópteros fue examinada a lo largo del Parque Nacional Sierra Nevada en la región Andina del estado Mérida, Venezuela. El PNSN es uno de las más grandes regiones protegidas y abarca dos subcuencas hidrográficas importantes. Muestras cuantitativas fueron recolectadas en 7 ríos tributarios de estas cuencas a lo largo del PNSN desde febrero a mayo del 2009, con un total de 135 individuos de 4 especies del género Anacroneuria. Sólo en tres ríos (Nuestra Señora, La Picón y Corcovada se encontró la presencia de plecópteros, los análisis de componentes principales muestran que la caracterización del hábitat, la velocidad de la corriente, el oxígeno disuelto y la ausencia de fuentes de perturbación antrópica influyen en un hábitat idóneo para las poblaciones. Los plecópteros se hallan en peligro de desaparición o incluso se han llegado a extinguir en gran parte de su área de distribución como consecuencia de actividades humanas. Planes de conservación deben ser implementados con urgencia, como evitar zonas recreacionales y/o económicas en las cercanías de los mismos.Population status of insects of Plecoptera order in Sierra Nevada National Park in Venezuela and its implications for conservation planning. Longitudinal distribution of Plecoptera species were examined along the Sierra Nevada National Park in the Andean region of Merida State, Venezuela. PNSN is one of the largest protected areas and consists of two major sub-basins. Quantitative samples were collected in 7 river tributaries along the PNSN from February to May of 2009, and a total of 135 individuals and 4 species of the genus Anacroneuria were collected. Only three rivers (Nuestra Señora, La Picón y Corcovada found the presence of stoneflies, the principal component analysis show that the characterization of habitat, current velocity, dissolved oxygen and the absence of human disturbance sources of influence in

  13. EL DISEÑO DE ITINERARIOS TURÍSTICOS PARA LA PUESTA EN VALOR DEL PATRIMONIO TERRITORIAL. LAS ACEQUIAS DE CAREO EN EL PARQUE NACIONAL DE SIERRA NEVADA

    Directory of Open Access Journals (Sweden)

    María José Prados Velasco

    2011-01-01

    Full Text Available Este artículo propone el diseño de itinerarios turísticos apoyados en el sistema de acequias de careo en la cuenca del Guadalfeo, en la vertiente sur del Parque Nacional de Sierra Nevada. Las acequias de careo son elementos claves empleados en la Antigüedad para la funcionalidad de los espacios agrarios de alta montaña en zonas semiáridas. En la actualidad constituyen elementos patrimoniales de primer orden que contribuyen al mantenimiento de los paisajes culturales. El objetivo central es el de vincular la sostenibilidad en la práctica del turismo, con la puesta en valor de elementos patrimoniales y paisajísticos.

  14. Temporal trend of the snow-related variables in Sierra Nevada in the last years: An analysis combining Earth Observation and hydrological modelling

    Science.gov (United States)

    Pérez-Luque, Antonio J.; Herrero, Javier; Bonet, Francisco J.; Pérez-Pérez, Ramón

    2016-04-01

    Climate change is causing declines in snow-cover extent and duration in European mountain ranges. This is especially important in Mediterranean mountain ranges where the observed trends towards precipitation and higher temperatures can provoke problems of water scarcity. In this work, we analyzed temporal trends (2000 to 2014) of snow-related variables obtained from satellite and modelling data in Sierra Nevada, a Mediterranean high-mountain range located in Southern Spain, at 37°N. Snow cover indicators (snow-cover duration, snow-cover onset dates and snow-cover melting dates) were obtained by processing images of MOD10A2 MODIS product using an automated workflow. Precipitation data were obtained using WiMMed, a complete and fully distributed hydrological model that is used to map the annual rainfall and snowfall with a resolution of 30x30 m over the whole study area. It uses expert algorithms to interpolate precipitation and temperature at an hourly scale, and simulates partition of precipitation into snowfall with several methods. For each snow-related indicator (snow-covers and snowfall), a trend analysis was applied at the MODIS pixel scale during the study period (2000-2014). We applied Mann-Kendall test and Theil-Sen slope estimation in each of the pixels comprising Sierra Nevada. The trend analysis assesses the intensity, magnitude and degree of statistical significance during the period analysed. The spatial pattern of these trends was explored according to elevation ranges. Finally, we explored the relationship between trends of snow-cover related indicators and precipitation trends. Our results show that snow-cover has undergone significant changes in the last 14 years. 80 % of the pixels covering Sierra Nevada showed a negative trend in the duration of snow-cover. We also observed a delay in the snow-cover onset date (68.03 % pixels showing a positive trend in the snow-cover onset date) and an advance in the melt date (80.72 % of pixels followed a

  15. A Blend of Ethanol and (-)-α-Pinene were Highly Attractive to Native Siricid Woodwasps (Siricidae, Siricinae) Infesting Conifers of the Sierra Nevada and the Allegheny Mountains.

    Science.gov (United States)

    Erbilgin, Nadir; Stein, Jack D; Acciavatti, Robert E; Gillette, Nancy E; Mori, Sylvia R; Bischel, Kristi; Cale, Jonathan A; Carvalho, Carline R; Wood, David L

    2017-02-01

    Woodwasps in Sirex and related genera are well-represented in North American conifer forests, but the chemical ecology of native woodwasps is limited to a few studies demonstrating their attraction to volatile host tree compounds, primarily monoterpene hydrocarbons and monoterpene alcohols. Thus, we systematically investigated woodwasp-host chemical interactions in California's Sierra Nevada and West Virginia's Allegheny Mountains. We first tested common conifer monoterpene hydrocarbons and found that (-)-α-pinene, (+)-3-carene, and (-)-β-pinene were the three most attractive compounds. Based on these results and those of earlier studies, we further tested three monoterpene hydrocarbons and four monoterpene alcohols along with ethanol in California: monoterpene hydrocarbons caught 72.3% of all woodwasps. Among monoterpene hydrocarbons, (+)-3-carene was the most attractive followed by (-)-β-pinene and (-)-α-pinene. Among alcohols, ethanol was the most attractive, catching 41.4% of woodwasps trapped. Subsequent tests were done with fewer selected compounds, including ethanol, 3-carene, and ethanol plus (-)-α-pinene in both Sierra Nevada and Allegheny Mountains. In both locations, ethanol plus (-)-α-pinene caught more woodwasps than other treatments. We discussed the implications of these results for understanding the chemical ecology of native woodwasps and invasive Sirex noctilio in North America. In California, 749 woodwasps were caught, representing five species: Sirex areolatus Cresson, Sirex behrensii Cresson, Sirex cyaneus Fabricius, Sirex longicauda Middlekauff, and Urocerus californicus Norton. In West Virginia 411 woodwasps were caught representing four species: Sirex edwardsii Brullé, Tremex columba Linnaeus, Sirex nigricornis F., and Urocerus cressoni Norton.

  16. Fuel buildup and potential fire behavior after stand-replacing fires, logging fire-killed trees and herbicide shrub removal in Sierra Nevada forests

    Science.gov (United States)

    McGinnis, Thomas W.; Keeley, Jon E.; Stephens, Scott L.; Roller, Gary B.

    2010-01-01

    Typically, after large stand-replacing fires in mid-elevation Sierra Nevada forests, dense shrub fields occupy sites formerly occupied by mature conifers, until eventually conifers overtop and shade out shrubs. Attempting to reduce fuel loads and expedite forest regeneration in these areas, the USDA Forest Service often disrupts this cycle by the logging of fire-killed trees, replanting of conifers and killing of shrubs. We measured the effects of these treatments on live and dead fuel loads and alien species and modeled potential fire behavior and fire effects on regenerating forests. Sampling occurred in untreated, logged and herbicide-treated stands throughout the Sierra Nevada in four large fire areas 4–21 years after stand-replacing fires. Logging fire-killed trees significantly increased total available dead fuel loads in the short term but did not affect shrub cover, grass and forb cover, alien species cover or alien species richness. Despite the greater available dead fuel loads, fire behavior was not modeled to be different between logged and untreated stands, due to abundant shrub fuels in both logged and untreated stands. In contrast, the herbicide treatment directed at shrubs resulted in extremely low shrub cover, significantly greater alien species richness and significantly greater alien grass and forb cover. Grass and forb cover was strongly correlated with solar radiation on the ground, which may be the primary reason that grass and forb cover was higher in herbicide treated stands with low shrub and tree cover. Repeat burning exacerbated the alien grass problem in some stands. Although modeled surface fire flame lengths and rates of spread were found to be greater in stands dominated by shrubs, compared to low shrub cover conifer plantations, surface fire would still be intense enough to kill most trees, given their small size and low crown heights in the first two decades after planting.

  17. Managing Sierra Nevada forests

    Science.gov (United States)

    Malcolm North

    2012-01-01

    There has been widespread interest in applying new forest practices based on concepts presented in U.S. Forest Service General Technical Report PSW-GTR-220, "An Ecosystem Management Strategy for Sierran Mixed-Conifer Forests." This collection of papers (PSW-GTR-237) summarizes the state of the science in some topics relevant to this forest management approach...

  18. Continuous Lake-Sediment Records of Glaciation in the Sierra Nevada between 52,600 and 12,500 14C yr B.P

    Science.gov (United States)

    Benson, Larry V.; May, Howard M.; Antweiler, Ronald C.; Brinton, Terry I.; Kashgarian, Michaele; Smoot, Joseph P.; Lund, Steve P.

    1998-09-01

    The chemistry of the carbonate-free clay-size fraction of Owens Lake sediments supports the use of total organic carbon and magnetic susceptibility as indicators of stadial-interstadial oscillations. Owens Lake records of total organic carbon, magnetic susceptibility, and chemical composition of the carbonate-free, clay-size fraction indicate that Tioga glaciation began ˜24,500 and ended by ˜13,600 14C yr B.P. Many of the components of glacial rock flour (e.g., TiO 2, MnO, BaO) found in Owens Lake sediments achieved maximum values during the Tioga glaciation when valley glaciers reached their greatest extent. Total organic carbon and SiO 2(amorphous) concentrations reached minimum values during Tioga glaciation, resulting from decreases in productivity that accompanied the introduction of rock flour into the surface waters of Owens Lake. At least 20 stadial-interstadial oscillations occurred in the Sierra Nevada between 52,600 and 14,000 14C yr B.P. Total organic carbon data from a Pyramid Lake sediment core also indicate oscillations in glacier activity between >39,500 and ˜13,600 14C yr B.P. Alpine glacier oscillations occurred on a frequency of ≤1900 yr in both basins, suggesting that millennial-scale oscillations occurred in California and Nevada during most of the past 52,600 yr.

  19. Radiocarbon and cation-radio ages for rock varnish on Tioga and Tahoe marainal boulders of Pine Creek, eastern Sierra Nevada, California, and their paleoclimatic implications

    Science.gov (United States)

    Dorn, R.I.; Turrin, B.D.; Jull, A.J.T.; Linick, T.W.; Donahue, D.J.

    1987-01-01

    Accelerator mass spectrometry 14C analyses of organic matter extracted from rock varnishes on morainal boulders yield limiting minimum ages for three crests of the Tioga glaciation. At Pine Creek in the eastern Sierra Nevada, varnish started to form on boulders of the outermost Tioga moraine before 19,000 yr B.P., and varnish originated on the innermost Tioga moraine before 13,200 yr B.P. Comparisons with lake-level, paleohydrological, paleoecological, colluvial, and rock varnish micromorphological data indicate that central-eastern California and western Nevada experienced a moisture-effective period during the late Pleistocene but after the Tioga maximum, and perhaps as Tioga glaciers receded from the mouth of Pine Creek canyon. Varnishes on Tahoeage morainal boulders at Pine Creek have cation-ratio ages of about 143,000-156,000 yr B.P., suggesting that the Tahoe glaciation should not be correlated with oxygen-isotope stage 4 in the early Wisconsin, but rather with stage 6. Varnishes on morainal boulders of an older glaciation at Pine Creek are dated by cation ratio at about 182,000-187,000 yr B.P. ?? 1987.

  20. Nevada

    International Nuclear Information System (INIS)

    Noble, D.C.; Plouff, D.; Close, T.J.; Bergquist, J.R.; Neumann, T.R.

    1987-01-01

    The part of the High Rock Late Wilderness Study Area, requested for mineral surveys by the Bureau of Land Management, encompasses 14,000 acres in the northern part of the Calico Mountains, Northwest Nevada. No resources were identified in the study area; however, there is low potential throughout the study area for volcanic-hosted deposits of mercury, uranium, and disseminated gold. The northern part of the study area has low potential for geothermal energy

  1. Mastication and prescribed fire impacts on fuels in a 25-year old ponderosa pine plantation, southern Sierra Nevada

    Science.gov (United States)

    Alicia L. Reiner; Nicole M. Vaillant; JoAnn Fites-Kaufman; Scott N. Dailey

    2009-01-01

    Due to increases in tree density and hazardous fuel loading in Sierra Nevadan forests, land management is focusing on fuel reduction treatments to moderate the risk of catastrophic fires. Fuel treatments involving mechanical and prescribed fire methods can reduce surface as well as canopy fuel loads. Mastication is a mechanical method which shreds smaller trees and...

  2. Pleistocene lake outburst floods and fan formation along the eastern Sierra Nevada, California: implications for the interpretation of intermontane lacustrine records

    Science.gov (United States)

    Benn, Douglas I.; Owen, Lewis A.; Finkel, Robert C.; Clemmens, Samuel

    2006-11-01

    Variations in the rock flour fraction in intermontane lacustrine sediments have the potential to provide more complete records of glacier fluctuations than moraine sequences, which are subject to erosional censoring. Construction of glacial chronologies from such records relies on the assumption that rock flour concentration is a simple function of glacier extent. However, other factors may influence the delivery of glacigenic sediments to intermontane lakes, including paraglacial adjustment of slope and fluvial systems to deglaciation, variations in precipitation and snowmelt, and lake outburst floods. We have investigated the processes and chronology of sediment transport on the Tuttle and Lone Pine alluvial fans in the eastern Sierra Nevada, California, USA, to elucidate the links between former glacier systems located upstream and the long sedimentary record from Owens Lake located downstream. Aggradation of both fans reflects sedimentation by three contrasting process regimes: (1) high magnitude, catastrophic floods, (2) fluvial or glacifluvial river systems, and (3) debris flows and other slope processes. Flood deposits are represented by multiple boulder beds exposed in section, and extensive networks of large palaeochannels and boulder deposits on both fan surfaces. Palaeohydrological analysis implies peak discharges in the order of 10 3-10 4 m 3 s -1, most probably as the result of catastrophic drainage of ice-, moraine-, and landslide-dammed lakes. Cosmogenic radionuclide surface exposure dating shows that at least three flood events are represented on each fan, at 9-13, 16-18 and 32-44 ka (Tuttle Fan); and at ˜23-32, ˜80-86 ka, and a poorly constrained older event (Lone Pine Fan). Gravels and sands exposed in both fans represent fluvial and/or glacifluvial sediment transport from the Sierra Nevada into Owens Valley, and show that river systems incised and reworked older sediment stored in the fans. We argue that millennial-scale peaks in rock flour

  3. Tree mortality from fire and bark beetles following early and late season prescribed fires in a Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    Schwilk, Dylan W.; Knapp, Eric E.; Ferrenberg, Scott; Keeley, Jon E.; Caprio, Anthony C.

    2006-01-01

    Over the last century, fire exclusion in the forests of the Sierra Nevada has allowed surface fuels to accumulate and has led to increased tree density. Stand composition has also been altered as shade tolerant tree species crowd out shade intolerant species. To restore forest structure and reduce the risk of large, intense fires, managers have increasingly used prescription burning. Most fires prior to EuroAmerican settlement occurred during the late summer and early fall and most prescribed burning has taken place during the latter part of this period. Poor air quality and lack of suitable burn windows during the fall, however, have resulted in a need to conduct more prescription burning earlier in the season. Previous reports have suggested that burning during the time when trees are actively growing may increase mortality rates due to fine root damage and/or bark beetle activity. This study examines the effects of fire on tree mortality and bark beetle attacks under prescription burning during early and late season. Replicated early season burn, late season burn and unburned control plots were established in an old-growth mixed conifer forest in the Sierra Nevada that had not experienced a fire in over 120 years. Although prescribed burns resulted in significant mortality of particularly the smallest tree size classes, no difference between early and late season burns was detected. Direct mortality due to fire was associated with fire intensity. Secondary mortality due to bark beetles was not significantly correlated with fire intensity. The probability of bark beetle attack on pines did not differ between early and late season burns, while the probability of bark beetle attack on firs was greater following early season burns. Overall tree mortality appeared to be primarily the result of fire intensity rather than tree phenology at the time of the burns. Early season burns are generally conducted under higher fuel moisture conditions, leading to less fuel

  4. Application of the Ecosystem Disturbance and Recovery Tracker in Detection of Forest Health Departure from Desired Conditions in Sierra Nevada National Forests

    Science.gov (United States)

    Slaton, M.; Koltunov, A.; Ramirez, C.

    2016-12-01

    Three Sierra Nevada national forests have recently released draft revised land management plans to the public for comment. These plans include components guiding land management projects (e.g. timber harvest) over the next decades. Desired conditions for land cover types were identified, and are based on the concept of the natural range of variability (NRV); the agency aims to achieve vegetation structure and composition that is within the range that has occurred in that system during the Holocene, prior to Euro-American settlement. Such systems are identified as having ecological integrity, with the ability to withstand and recover from disturbance. Comparisons between current conditions and the NRV period are often made qualitatively, with quantitative comparisons possible through the reconstruction of forest parameters using paleoecological evidence such as pollen or tree rings. Where such information is lacking, comparisons can be made using more recent data for locations or time periods believed to closely represent NRV. Such evaluations are necessary to develop projects that will be within the agency's desired conditions. As an example, the most recent estimate of the extent of tree mortality in CA continues to rise and expand at an aggressive rate, creating the need to track progress as compared to baseline conditions. The Ecosystem Disturbance and Recovery Tracker (eDaRT) is a system developed by the US Forest Service Region 5 Remote Sensing Lab and UC Davis CSTARS center that uses all available Landsat imagery to detect anomalies in vegetation indices, and has been adapted to detect current tree mortality as compared to modern pre-drought baseline conditions. We present initial results for the southern Sierra Nevada (5,260,913 hectares; 13 million acres) that have been validated using WorldView imagery and field data. The high spatial resolution and large extent of the dataset as compared to other mortality maps enabled identification of factors correlated

  5. Climate change and tree-line ecosystems in the Sierra Nevada: Habitat suitability modelling to inform high-elevation forest dynamics monitoring

    Science.gov (United States)

    Moore, Peggy E.; Alvarez, Otto; McKinney, Shawn T.; Li, Wenkai; Brooks, Matthew L.; Guo, Qinghua

    2017-01-01

    Whitebark pine and foxtail pine serve foundational roles in the subalpine zone of the Sierra Nevada. They provide the dominant structure in tree-line forests and regulate key ecosystem processes and community dynamics. Climate change models suggest that there will be changes in temperature regimes and in the timing and magnitude of precipitation within the current distribution of these species, and these changes may alter the species’ distributional limits. Other stressors include the non-native pathogen white pine blister rust and mountain pine beetle, which have played a role in the decline of whitebark pine throughout much of its range. The National Park Service is monitoring status and trends of these species. This report provides complementary information in the form of habitat suitability models to predict climate change impacts on the future distribution of these species within Sierra Nevada national parks.We used maximum entropy modeling to build habitat suitability models by relating species occurrence to environmental variables. Species occurrence was available from 328 locations for whitebark pine and 244 for foxtail pine across the species’ distributions within the parks. We constructed current climate surfaces for modeling by interpolating data from weather stations. Climate surfaces included mean, minimum, and maximum temperature and total precipitation for January, April, July, and October. We downscaled five general circulation models for the 2050s and the 2090s from ~125 km2 to 1 km2 under both an optimistic and an extreme climate scenario to bracket potential climatic change and its influence on projected suitable habitat. To describe anticipated changes in the distribution of suitable habitat, we compared, for each species, climate scenario, and time period, the current models with future models in terms of proportional change in habitat size, elevation distribution, model center points, and where habitat is predicted to expand or contract

  6. Prevalencia de patologías tropicales y factores de riesgo en la comunidad indígena de bunkwimake, sierra nevada de Santa Marta

    Directory of Open Access Journals (Sweden)

    Juan C. Dib

    2013-10-01

    Full Text Available Las enfermedades tropicales son endémicas en la Sierra Nevada de Santa Marta, sin embargo se carece de información acerca de la distribución de estas enfermedades en las comunidades indígenas que la habitan. Mediante estudios entomológicos y seroepidemiológicos, se estudiaron los factores de riesgo y la prevalencia de enfermedad de Chagas, leishmaniosis, hepatitis B y parasitosis intestinales en la comunidad indígena de Bunkwimake, ubicada en la vertiente norte de la Sierra Nevada. Los resultados de los estudios serológicos en 94 individuos reportaron una positividad de 18 (19%, 52(55% y 19(20% para infección por Tripanosoma cruzi, leishmania y el virus de la hepatitis B respectivamente. Adicionalmente, en 41(74% de 56 niños indígenas se encontró la presencia de parasitosis intestinales al examen coprológico. En los estudios entomológicos se captu-raron 37 triatominos en 16 viviendas distribuidos de la siguiente manera: 13 Triatoma dimidiata, 12 Rhodnius prolixus y 12 Pastrongylus geniculatus. Las tres especies se encontraron colonizando las viviendas indígenas y presentaron infeccilón para Trypanosoma cruzi. Dos especies de flebotominos fueron capturados en las vivien-das: 5 lutzomyia Gomezi y 7 Lutzomyia hirsute hirsute. El presente estudio demostró una importante prevalencia de infección por T. Cruzi y Leishmania en la población infantil, indicando transmisión reciente de ambas infec-ciones. Adicionalmente, los estudios entomológicos indican que existe un riesgo de transmisión doméstica de T. Cruzi y Leishmania por especies selváticas de triatominos y flebotominos. Se necesitan estudios adicionales que determinen la ecoepidemiología y dinámicas de trasnmisión de la Leishmanisosis y la enfermedad de Chagas en esta población para diseñar estrategias de control más adecuadas. Debido a que los programas verticales de fumigación y mejoramiento de vivienda en las comunidades indígenas no son viables, nuevas

  7. Arsenic associated with historical gold mining in the Sierra Nevada foothills: Case study and field trip guide for Empire Mine State Historic Park, California

    Science.gov (United States)

    Alpers, Charles N.; Myers, Perry A; Millsap, Daniel; Regnier, Tamsen B; Bowell, Robert J.; Alpers, Charles N.; Jamieson, Heather E.; Nordstrom, D. Kirk; Majzlan, Juraj

    2014-01-01

    The Empire Mine, together with other mines in the Grass Valley mining district, produced at least 21.3 million troy ounces (663 tonnes) of gold (Au) during the 1850s through the 1950s, making it the most productive hardrock Au mining district in California history (Clark 1970). The Empire Mine State Historic Park (Empire Mine SHP or EMSHP), established in 1975, provides the public with an opportunity to see many well-preserved features of the historic mining and mineral processing operations (CDPR 2014a).A legacy of Au mining at Empire Mine and elsewhere is contamination of mine wastes and associated soils, surface waters, and groundwaters with arsenic (As), mercury (Hg), lead (Pb), and other metals. At EMSHP, As has been the principal contaminant of concern and the focus of extensive remediation efforts over the past several years by the State of California, Department of Parks and Recreation (DPR) and Newmont USA, Ltd. In addition, the site is the main focus of a multidisciplinary research project on As bioavailability and bioaccessibility led by the California Department of Toxic Substances Control (DTSC) and funded by the U.S. Environmental Protection Agency’s (USEPA’s) Brownfields Program.This chapter was prepared as a guide for a field trip to EMSHP held on June 14, 2014, in conjunction with a short course on “Environmental Geochemistry, Mineralogy, and Microbiology of Arsenic” held in Nevada City, California on June 15–16, 2014. This guide contains background information on geological setting, mining history, and environmental history at EMSHP and other historical Au mining districts in the Sierra Nevada, followed by descriptions of the field trip stops.

  8. The remarkable occurrence of large rainfall-induced debris flows at two different locations on July 12, 2008, Southern Sierra Nevada, CA, USA

    Science.gov (United States)

    DeGraff, J.V.; Wagner, D.L.; Gallegos, A.J.; DeRose, M.; Shannon, C.; Ellsworth, T.

    2011-01-01

    On July 12, 2008, two convective cells about 155 km apart produced a brief period of intense rainfall triggering large debris flows in the southern Sierra Nevada. The northernmost cell was centered over Oak Creek Canyon, an east-flowing drainage, and its tributaries near Independence, CA, USA. About 5:00 P.M., debris flows passed down the South Fork and North Fork of Oak Creek to merge into a large single feature whose passage affected the historic Mt. Whitney Fish hatchery and blocked California State Highway 395. At about the same time, the southernmost cell was largely centered over Erskine Creek, a main tributary of the west-flowing Kern River. Debris flows issued from several branches to coalesce into a large debris flow that passed along Erskine Creek, through the town of Lake Isabella, CA, USA and into the Kern River. It was observed reaching Lake Isabella about 6:30 P.M. Both debris flows caused significant disruption and damage to local communities. ?? 2011 Springer-Verlag.

  9. Solar storm effects during Saint Patrick's Days in 2013 and 2015 on the Schumann resonances measured by the ELF station at Sierra Nevada (Spain)

    Science.gov (United States)

    Salinas, A.; Toledo-Redondo, S.; Navarro, E. A.; Fornieles-Callejón, J.; Portí, J. A.

    2016-12-01

    The effects of solar storms occurring during the days 17 to 19 March 2013 and 2015, St. Patrick's Day intervals, on Schumann resonances (SRs) have been studied. To do this, the experimental data recorded by the Juan Antonio Morente extremely low frequency station located at Sierra Nevada, Spain, have been processed in order to obtain hourly averaged information on the first three resonance modes. Results are compared with monthly averages of the SR data for each hour to detect deviations from the regular behavior. Evidence of significant changes in the peak amplitudes and frequencies of the SRs have been identified in the station's measurements and related to the coronal mass ejection impact in the magnetosphere, detected by in situ plasma measurements onboard spacecraft in the solar wind. However, the complicated nature of the Schumann resonances, dependent on multiple variables and subject to multiple unavoidable interferences (e.g., lightning or human radio sources), in conjunction with the complex magnetosphere-ionosphere-atmosphere coupling processes, makes it difficult to conclude that the observed deviations are exclusively due to the solar events mentioned. Results extracted from only two solar events cannot be considered as conclusive, and therefore, independent comparison with results reported by other research would seem advisable in future works on this subject.

  10. Climate variability during the deglaciation and Holocene in a high-altitude alpine lake deduced from the sedimentary record from Laguna Seca, Sierra Nevada, southern Iberian Peninsula

    Science.gov (United States)

    Camuera, Jon; Jiménez-Moreno, Gonzalo; José Ramos-Román, María; García-Alix, Antonio; Jiménez-Espejo, Francisco; Anderson, R. Scott

    2017-04-01

    High-resolution X-ray fluorescence (XRF), magnetic susceptibility (MS), color and lithological analyses have been carried out on a 3.6 m-long sediment core from Laguna Seca, a high-elevation dry lake from Sierra Nevada mountain range, southern Spain. This is the longest sedimentary record retrieved from an alpine lake in southern Iberian Peninsula. Besides, alpine lakes are very sensitive environments to climate changes and previous studies showed that Laguna Seca could provide an excellent record to identify millennial-scale climate variations during deglaciation and the whole Holocene. XRF analyses, in particular high calcium and low K/Ca ratios, show aridity phases, very well represented during Last Glacial Maximum (LGM) and the Younger Dryas (YD). Arid events are also shown at ca. 8.1 ka BP, ca. 4.4 ka BP and the latest Holocene. On the other hand, negative values in calcium and positive values in K/Ca appear in the Bølling-Allerød (BA) and during the early Holocene until ca. 6 ka BP, indicating more humidity and higher run-off. A progressive aridification trend is also observed in the Holocene, changing from more humid conditions during the early Holocene to more aridity during the late Holocene.

  11. High abundances of potentially active ammonia-oxidizing bacteria and archaea in oligotrophic, high-altitude lakes of the Sierra Nevada, California, USA.

    Directory of Open Access Journals (Sweden)

    Curtis J Hayden

    Full Text Available Nitrification plays a central role in the nitrogen cycle by determining the oxidation state of nitrogen and its subsequent bioavailability and cycling. However, relatively little is known about the underlying ecology of the microbial communities that carry out nitrification in freshwater ecosystems--and particularly within high-altitude oligotrophic lakes, where nitrogen is frequently a limiting nutrient. We quantified ammonia-oxidizing archaea (AOA and bacteria (AOB in 9 high-altitude lakes (2289-3160 m in the Sierra Nevada, California, USA, in relation to spatial and biogeochemical data. Based on their ammonia monooxygenase (amoA genes, AOB and AOA were frequently detected. AOB were present in 88% of samples and were more abundant than AOA in all samples. Both groups showed >100 fold variation in abundance between different lakes, and were also variable through time within individual lakes. Nutrient concentrations (ammonium, nitrite, nitrate, and phosphate were generally low but also varied across and within lakes, suggestive of active internal nutrient cycling; AOB abundance was significantly correlated with phosphate (r(2 = 0.32, p<0.1, whereas AOA abundance was inversely correlated with lake elevation (r(2 = 0.43, p<0.05. We also measured low rates of ammonia oxidation--indicating that AOB, AOA, or both, may be biogeochemically active in these oligotrophic ecosystems. Our data indicate that dynamic populations of AOB and AOA are found in oligotrophic, high-altitude, freshwater lakes.

  12. A Gap-Filling Procedure for Hydrologic Data Based on Kalman Filtering and Expectation Maximization: Application to Data from the Wireless Sensor Networks of the Sierra Nevada

    Science.gov (United States)

    Coogan, A.; Avanzi, F.; Akella, R.; Conklin, M. H.; Bales, R. C.; Glaser, S. D.

    2017-12-01

    Automatic meteorological and snow stations provide large amounts of information at dense temporal resolution, but data quality is often compromised by noise and missing values. We present a new gap-filling and cleaning procedure for networks of these stations based on Kalman filtering and expectation maximization. Our method utilizes a multi-sensor, regime-switching Kalman filter to learn a latent process that captures dependencies between nearby stations and handles sharp changes in snowfall rate. Since the latent process is inferred using observations across working stations in the network, it can be used to fill in large data gaps for a malfunctioning station. The procedure was tested on meteorological and snow data from Wireless Sensor Networks (WSN) in the American River basin of the Sierra Nevada. Data include air temperature, relative humidity, and snow depth from dense networks of 10 to 12 stations within 1 km2 swaths. Both wet and dry water years have similar data issues. Data with artificially created gaps was used to quantify the method's performance. Our multi-sensor approach performs better than a single-sensor one, especially with large data gaps, as it learns and exploits the dominant underlying processes in snowpack at each site.

  13. Analysis of rhizobial endosymbionts of Vicia, Lathyrus and Trifolium species used to maintain mountain firewalls in Sierra Nevada National Park (South Spain).

    Science.gov (United States)

    Villadas, Pablo J; Lasa, Ana V; Martínez-Hidalgo, Pilar; Flores-Félix, José David; Martínez-Molina, Eustoquio; Toro, Nicolás; Velázquez, Encarna; Fernández-López, Manuel

    2017-03-01

    Forest fires lead to the annual disappearance of many natural formations that require the creation of firewall areas. They can be maintained by enriching their pastures with attractive plants for grazing livestock, mainly legumes, which have a high protein content and low dependence on N fertilizers due to their ability to establish nitrogen-fixing symbiosis with rhizobia. In this study, the rhizobia isolated from the nodules of six legumes from the genera Vicia, Lathyrus and Trifolium were analysed in a firewall zone established in Lanjarón (Granada) close to the Sierra Nevada National Park (Spain). The results showed a high genetic diversity of the isolated strains that had 3, 16, 14 and 13 different types of rrs, recA, atpD and glnII genes, respectively. All strains were phylogenetically close to the species from the Rhizobium leguminosarum group, although they were not identified as any of them. The isolated strains belonged to the symbiovars viciae and trifolii but high phylogenetic diversity was found within both symbiovars, since there were 16 and 14 nodC gene types, respectively. Some of these strains clustered with strains isolated in other countries and continents, but others formed atpD, recA, glnII and nodC clusters and lineages only found to date in this study. Copyright © 2016 Elsevier GmbH. All rights reserved.

  14. Secondary metabolites of lichens in the snow zone of the Sierra Nevada in Mérida-Venezuela and their role in the absorption of ultraviolet radiation

    International Nuclear Information System (INIS)

    Rojas Fernández, J.A.; Balza Quintero, A.; Marcano, V.; Rojas, P.A.; Dávila Vera, D.; Peña Contreras, Z.; Mendoza Briceño, R.V.; Palacios Prü, E.

    2008-01-01

    Photochemical analyses of secondary compounds in lichens from the Venezuelan Andean snow zone were carried out in order to know the absorbance capacity of UV radiation at the UVA, UVB and UVC ranges and to determine its probable UV protective function. Spectrophotometric (UV) and fine layer chromatographic techniques (TLC) were utilized to separate and identify the compounds. UV radiation values were obtained from the Red Bioclimática del Parque Nacional Sierra Nevada de Mérida which constitutes a program supported by the University of Los Andes, Venezuela. Results indicated the existence of 22 species of lichens at the snow zone; 55% of these species showed a strong resistance to UVC radiation, 95% to UVB radiation, whereas the 100% revealed a strong resistance to UVA radiation. The substances that have the highest resistance to UVA and UVB radiation are characterized by having ester bonds among phenolic units depsids and constitute the most abundant products in lichens, whereas the substances having both ester and ether bonds among the two phenolic units depsidones revealed a higher capacity to absorb UVC radiation that could indicate a primitive origin [es

  15. A new population record and conservation assessment of the Santa Marta Poison Arrow Frog Colostethus ruthveni Kaplan, 1997 (Anura: Dendrobatidae from Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    J.F.G. Maya

    2011-03-01

    Full Text Available Colombia possesses important amphibian species richness that is threatened by several factors. Here we report a new population of the Santa Marta Poison Arrow Frog Colostethus ruthveni, an endangered endemic species from Sierra Nevada de Santa Marta mountain range. During intensive surveys across Námaku Reserve, 22 C. ruthveni individuals (mean abundance 0.28 plus or minus 0.09 ind/km were observed along creeks between 737 and 923m above sea level near downtown Minca. This record represents a new locality for the species, increasing the number of known sites and expanding its extent of occurrence. We suggest the reassessment of the conservation status of the species from EN B1ab(iii to VU B1ab(iii, due to this and other recent findings. Currently, the species is present in three protected areas; this new record represents another reserve area where the species is distributed, ensuring the habitat and reducing some of its most important threats such as habitat loss and degradation from agricultural activities, logging, pollution and infrastructure development. This finding represents new critical information for the species and defines the need to understand the real status of its populations for future conservation strategies in the region.

  16. Fire decreases arthropod abundance but increases diversity: Early and late season prescribed fire effects in a Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    Ferrenberg, Scott; Schwilk, Dylan W.; Knapp, Eric E.; Groth, Eric; Keeley, Jon E.

    2006-01-01

    Prior to fire suppression in the 20th century, the mixed-conifer forests of the Sierra Nevada, California, U.S.A., historically burned in frequent fires that typically occurred during the late summer and early fall. Fire managers have been attempting to restore natural ecosystem processes through prescription burning, and have often favored burning during the fall in order to mimic historical fire regimes. Increasingly, however, prescription burning is also being done during the late spring and early summer in order to expand the window of opportunity for needed fuel reduction burning. The effect of prescribed fires outside of the historical fire season on forest arthropods is not known. The objective of this study was to compare the short-term effects of prescribed fires ignited in the early and late fire season on forest floor arthropods. Arthropod abundance and diversity were assessed using pitfall trapping in replicated burn units in Sequoia National Park, California. Overall, abundance of arthropods was lower in the burn treatments than in the unburned control. However, diversity tended to be greater in the burn treatments. Fire also altered the relative abundances of arthropod feeding guilds. No significant differences in arthropod community structure were found between early and late season burn treatments. Instead, changes in the arthropod community appeared to be driven largely by changes in fuel loading, vegetation, and habitat heterogeneity, all of which differed more between the burned and unburned treatments than between early and late season burn treatments.

  17. Variable-Resolution Ensemble Climatology Modeling of Sierra Nevada Snowpack within the Community Earth System Model (CESM)

    Science.gov (United States)

    Rhoades, A.; Ullrich, P. A.; Zarzycki, C. M.; Levy, M.; Taylor, M.

    2014-12-01

    Snowpack is crucial for the western USA, providing around 75% of the total fresh water supply (Cayan et al., 1996) and buffering against seasonal aridity impacts on agricultural, ecosystem, and urban water demands. The resilience of the California water system is largely dependent on natural stores provided by snowpack. This resilience has shown vulnerabilities due to anthropogenic global climate change. Historically, the northern Sierras showed a net decline of 50-75% in snow water equivalent (SWE) while the southern Sierras showed a net accumulation of 30% (Mote et al., 2005). Future trends of SWE highlight that western USA SWE may decline by 40-70% (Pierce and Cayan, 2013), snowfall may decrease by 25-40% (Pierce and Cayan, 2013), and more winter storms may tend towards rain rather than snow (Bales et al., 2006). The volatility of Sierran snowpack presents a need for scientific tools to help water managers and policy makers assess current and future trends. A burgeoning tool to analyze these trends comes in the form of variable-resolution global climate modeling (VRGCM). VRGCMs serve as a bridge between regional and global models and provide added resolution in areas of need, eliminate lateral boundary forcings, provide model runtime speed up, and utilize a common dynamical core, physics scheme and sub-grid scale parameterization package. A cubed-sphere variable-resolution grid with 25 km horizontal resolution over the western USA was developed for use in the Community Atmosphere Model (CAM) within the Community Earth System Model (CESM). A 25-year three-member ensemble climatology (1980-2005) is presented and major snowpack metrics such as SWE, snow depth, snow cover, and two-meter surface temperature are assessed. The ensemble simulation is also compared to observational, reanalysis, and WRF model datasets. The variable-resolution model provides a mechanism for reaching towards non-hydrostatic scales and simulations are currently being developed with refined

  18. Rates and timing of vertical-axis block rotations across the Sierra Nevada-Walker Lane transition in the Bodie Hills

    Science.gov (United States)

    Rood, D. H.; Herman, S.; Burbank, D.; Bogue, S.

    2008-12-01

    We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotation across the Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. In zones of continental deformation, block rotations are an important mechanism for permanent stain accommodation, and thus may be crucial to testing geodetic block models and resolving geologic-geodetic slip discrepancies. In our study, data included in the paleomagetic site means are high quality AF demagnetization results (least squared fits that generally include 5-7 points with MAD values less than 1). Thermal demagnetization results match the AF directions, and both thermal demag and rockmag results indicate strong ChRM, mostly carried by single domain magnetite. The site means used to calculate the VGPs all have a95 values less than 10 (mostly 2-5) and include 6-11 sites each. Each site (and thus site mean) has a reasonably well-known structural correction. The VGP scatter values range from 12 to 16 degrees, indicating that they include appropriate secular variation. The mean declinations and 95 percent confidence limits for each VGP timeslice are statistically distinct from one another (71 ± 9, 39 ± 13, and 11 ± 11 degrees). The slope of a linear regression fit to the age versus declination data gives a rate of vertical axis block rotation of approximately 3-4 degrees/Myr. Fitting two separate lines to the age vs. declination data would indicate an increase in the rates of rotation since ~10 Ma. Two possible interpretations of the data are: (1) the rotations began during or before the Middle Miocene, or (2) rates of rotation were high initially (e.g. ~10 Ma) and decelerated until the Pliocene. These data have implications for the (1) timing and spatial extent of distributed strain accumulation related to the initiation of the San Andreas Fault-Eastern California Shear Zone-Walker Lane transform plate boundary, (2) transfer of transform plate boundary

  19. El Cuaternario en el macizo de Sierra Nevada. Evolución paleoambiental y paisaje a partir de la interpretación de registros naturales y documentos de época

    OpenAIRE

    Oliva, Marc; Gómez Ortiz, Antonio; Palacios Estremera, David; Salvador Franch, Ferran; Salvà i Catarineu, Montse

    2014-01-01

    El conocimiento relativo a la evolución ambiental cuaternaria en las montañas de la Península Ibérica ha avanzado sustancialmente en las últimas décadas. Particularmente significativos son los progresos realizados en el macizo de Sierra Nevada, en el sur peninsular. En este caso, los investigadores se han servido de registros naturales y fuentes documentales para reconstruir la dinámica ambiental desde la Última Glaciación y posterior deglaciación del macizo hasta su evolución reciente. Los c...

  20. Effect of climate variability and management practices on carbon, water and energy fluxes of a young Ponderosa pine plantation in the Sierra Nevada (CA)

    Science.gov (United States)

    Misson, L.; Tang, J.; McKay, M.; Goldstein, A. H.

    2003-04-01

    Despite the range and importance of semi-arid Ponderosa pine ecosystem in the United States, stand-scale fluxes of carbon, water and energy of these ecosystems have rarely been studied. Our research at the Blodgett Forest Research Station in the Sierra Nevada of California is advocated to better understand how these fluxes of a mid-elevation, young pine plantation vary interannually in response to climate variability, and how they are impacted by management practices such as shrub removal and thinning. Fluxes of CO2, H2O, and energy have been measured continuously since May 1999 by the eddy covariance method. Environmental parameters such as wind direction and speed, air temperature and humidity, net and photosynthetically active radiation, soil temperature, soil moisture, soil heat flux, rain, and atmospheric pressure are also monitored. Additional continuous measurements at the site have included O3 concentration and flux, and concentration and fluxes of a wide variety of volatile organic compounds. The data set covers periods characterized by various levels of drought stress. Shrub was removed in the spring 1999 and a precommercial thinning of 2/3 of the trees was applied in the spring 2000. Even during the winter, the young Ponderosa pine plantation at Blodgett acted mainly as a sink of carbon during the four years of measurement. The decrease of leaf area index and thus photosynthesis caused by thinning is the main factor that caused lower uptake, but increased respiration also occurred. These effects are limited in time and magnitude due to the rapidly increasing leaf area index after thinning. Beside this, the ability of this young pine plantation to act as a sink of carbon was also influenced by interannual variability of climate. Drought is a regular feature of the climate of California, making water availability the major controller of gas exchange in summer and fall. Freezing temperatures limit CO2 ecosystem uptake during the winter and tree growth in

  1. Oblique map showing maximum extent of 20,000-year-old (Tioga) glaciers, Yosemite National Park, central Sierra Nevada, California

    Science.gov (United States)

    Alpha, T.R.; Wahrhaftig, Clyde; Huber, N.K.

    1987-01-01

    This map shows the alpine ice field and associated valley glaciers at their maximum extent during the Tioga glaciation. The Tioga glaciation, which peaked about 15,000-20,OOO years ago, was the last major glaciation in the Sierra Nevada. The Tuolumne ice field fed not only the trunk glacier that moved down the Tuolumne River canyon through the present-day Hetch Hetchy Reservoir, but it also overflowed major ridge crests into many adjoining drainage systems. Some of the ice flowed over low passes to augment the flows moving from the Merced basin down through little Yosemite Valley. Tuolumne ice flowed southwest down the Tuolumne River into the Tenaya Lake basin and then down Tenaya Canyon to join the Merced glacier in Yosemite Valley. During the Tioga glaciation, the glacier in Yosemite Valley reached only as far as Bridalveil Meadow, although during a much earlier glaciation, a glacier extended about 10 miles farther down the Merced River to the vicinity of El Portal. Ice of the Tioga glaciation also flowed eastward from the summit region to cascade down the canyons that cut into the eastern escarpment of the Sierra Nevada [see errata, below]. Southeast of the present-day Yosemite Park, glaciers formed in the Mount Lyell region flowed east onto the Mono lowland and southeast and south down the Middle and North Forks of the San Joaquin River. In the southern part of the park, glaciers nearly reached to the present-day site of Wawona along the South Fork of the Merced River. At the time of the maximum extent of the Tioga glaciation, Lake Russell (Pleistocene Mono Lake) had a surface elevation of 6,800 feet, 425 feet higher than the 1980 elevation and 400 feet lower than its maximum level at the end of the Tioga glaciation. Only a few volcanic domes of the Mono Craters existed at the time of the Tioga glaciation. The distribution of vegetation, as suggested by the green overprint, is based on our interpretation. Forests were restricted to lower elevations than present

  2. [Relative abundance and microhabitat use by the frog Geobatrachus walkeri (Anura: Strabomantidae) in two habitats of Sierra Nevada de Santa Marta, Colombia].

    Science.gov (United States)

    Martínez Baños, Vera; Pacheco Florez, Vanesa; Ramírez-Pinilla, Martha P

    2011-06-01

    Geobatrachus walkeri belongs to a monotypic frog genus endemic to the San Lorenzo area, Sierra Nevada de Santa Marta, Colombia. This species has been categorized as endangered because of its small distribution area and the decline in the extent and quality of its habitat. It inhabits two forest types with different composition and structure, the native secondary forest and a pine plantation (dominated by Pinus patula). To compare the relative abundance and microhabitat use of this species in these habitat types, 30 quadrants/environment were distributed randomly. The individual number, microhabitat use and other aspects of its natural history were registered using visual encounter surveys in both sites, including non-sampled areas in the quadrants. The relative abundance of frogs was significantly different between habitats and among seasons. The highest abundance of G. walkeri relative to the total area was found in the pine plantation, being 2.3 times higher than in the natural forest. More frogs were significantly found during the rainy season; nevertheless, active individuals were also found during the dry season. Significant differences were found in the microhabitat use with respect to the forest type and season. The most frequently microhabitat used in the two forest types was the pine leaf-litter; besides, in the native forest, the microhabitat occupied more frequently presented medium and large size stones. Geobatrachus walkeri is a successful species in pine plantations, associated permanently to its leaf-litter environment where it seems to develop its entire life cycle. The clear modifications in the soils and water, derived from the introduction of the pine plantation in this area, seem not to have negatively affected the conservation and successful maintenance of this species.

  3. Responses of Plant Community Composition to Long-term Changes in Snow Depth at the Great Basin Desert - Sierra Nevada ecotone.

    Science.gov (United States)

    Loik, M. E.

    2015-12-01

    Snowfall is the dominant hydrologic input for many high-elevation ecosystems of the western United States. Many climate models envision changes in California's Sierra Nevada snow pack characteristics, which would severely impact the storage and release of water for one of the world's largest economies. Given the importance of snowfall for future carbon cycling in high elevation ecosystems, how will these changes affect seedling recruitment, plant mortality, and community composition? To address this question, experiments utilize snow fences to manipulate snow depth and melt timing at a desert-montane ecotone in eastern California, USA. Long-term April 1 snow pack depth averages 1344 mm (1928-2015) but is highly variable from year to year. Snow fences increased equilibrium drift snow depth by 100%. Long-term changes in snow depth and melt timing are associated with s shift from shurbs to graminoids where snow depth was increased for >50 years. Changes in snow have impacted growth for only three plant species. Moreover, annual growth ring increments of the conifers Pinus jeffreyi and Pi. contorta were not equally sensitive to snow depth. There were over 8000 seedlings of the shrubs Artemisia tridentata and Purshia tridentata found in 6300 m2 in summer 2009, following about 1400 mm of winter snow and spring rain. The frequency of seedlings of A. tridentata and P. tridentata were much lower on increased-depth plots compared to ambient-depth, and reduced-depth plots. Survival of the first year was lowest for A. tridentata. Survival of seedlings from the 2008 cohort was much higher for P. tridentata than A. tridentata during the 2011-2015 drought. Results indicate complex interactions between snow depth and plant community characteristics, and that responses of plants at this ecotone may not respond similarly to increases vs. decreases in snow depth. These changes portend altered carbon uptake in this region under future snowfall scenarios.

  4. Reproducción de Joturus pichardi y Agonostomus monticola(Mugiliformes: Mugilidae en ríos de la Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Pedro Eslava Eljaiek

    2011-12-01

    Full Text Available Para los mugílidos de agua dulce Joturus pichardi y Agonostomus monticola se han documentado aspectos ecológicos y de distribución, principalmente para las poblaciones de América Central, sin embargo, hay poca información disponible de sus aspectos reproductivos, especialmente en ambientes de agua dulce de Colombia. Por lo tanto para ambas especies se estudió la biología reproductiva en ríos de la Sierra Nevada de Santa Marta durante julio de 2005 y diciembre de 2006. En total, 14 especímenes de J. pichardi y 320 A. monticola fueron capturados. Proporción sexual, índice gonadosomático, talla media de madurez, fecundidad y diámetros de los ovocitos fueron evaluados. Se realizó un bioensayo para observar el efecto de la salinidad sobre la movilidad espermática y su posible relación con el área de desove de las especies. Estos mugílidos comparten un hábitat con características ecológicas similares, de corrientes fuertes y claras y zonas pedregosas. Indicadores de madurez gonadal y evidencias indirectas son presentados y con los cuales se comprueba que el periodo reproductivo se encuentra relacionado con los mayores valores de precipitación de la zona (septiembre a noviembre, así como, la migración catádroma de J. pichardi y A. monticola. Estas especies representan un potencial de cultivo, dado su alimentación basada en vegetales y macroinvertebrados, la calidad de su carne y las tallas que pueden alcanzar, por lo cual, se deben efectuar estudios más profundos que revelen mayor información sobre su comportamiento y reproducción en cautividad.

  5. Responses of Tree Growths to Tree Size, Competition, and Topographic Conditions in Sierra Nevada Forests Using Bi-temporal Airborne LiDAR Data

    Science.gov (United States)

    Ma, Q.; Su, Y.; Tao, S.; Guo, Q.

    2016-12-01

    Trees in the Sierra Nevada (SN) forests are experiencing rapid changes due to human disturbances and climatic changes. An improved monitoring of tree growth and understanding of how tree growth responses to different impact factors, such as tree competition, forest density, topographic and hydrologic conditions, are urgently needed in tree growth modeling. Traditional tree growth modeling mainly relied on field survey, which was highly time-consuming and labor-intensive. Airborne Light detection and ranging System (ALS) is increasingly used in forest survey, due to its high efficiency and accuracy in three-dimensional tree structure delineation and terrain characterization. This study successfully detected individual tree growth in height (ΔH), crown area (ΔA), and crown volume (ΔV) over a five-year period (2007-2012) using bi-temporal ALS data in two conifer forest areas in SN. We further analyzed their responses to original tree size, competition indices, forest structure indices, and topographic environmental parameters at individual tree and forest stand scales. Our results indicated ΔH was strongly sensitive to topographic wetness index; whereas ΔA and ΔV were highly responsive to forest density and original tree sizes. These ALS based findings in ΔH were consistent with field measurements. Our study demonstrated the promising potential of using bi-temporal ALS data in forest growth measurements and analysis. A more comprehensive study over a longer temporal period and a wider range of forest stands would give better insights into tree growth in the SN, and provide useful guides for forest growth monitoring, modeling, and management.

  6. TEJIENDO ENTRE REDES DIVERSAS: REFLEXIONES A PARTIR DE UNA ETNOGRAFÍA MULTISITUADA CON LOS PUEBLOS INDÍGENAS DE LA SIERRA NEVADA DE SANTA MARTA, CARIBE COLOMBIANO

    Directory of Open Access Journals (Sweden)

    Ana Milena Horta Prieto

    2014-06-01

    Full Text Available La Sierra Nevada de Santa Marta, Colombia, es territorio de 4 pueblos indígenas: Kogui, Wiwa, Arhuaco y Kankuamo. Estos comparten la Ley de Sé, orden natural del universo, que en este trabajo se aborda como cosmopolitica (Stengers, a partir de la cual se gestiona la alteridad y se define la función de todos los seres existentes, desde una ontología animista (Descola. Los trabajos espirituales, entre los cuales se cuentan los pagamentos, son rituales en los que se realiza el tejido vital entre entidades, a partir del cual pueden circular los flujos energéticos y de pensamiento, que relacionan mamos (autoridades tradicionales, dueños de los existentes (Jaba y jate, y materiales sagrados, en una relación de intercambio que permite que las partes se reconfiguren y se apropien del sewá (conocimiento que cada uno posee. Algunos de estos materiales han sido removidos del territorio, frente a lo cual las organizaciones indígenas han comenzado un proceso de patrimonialización como estrategia de protección, interactuando con entidades del estado que tienen influencia en la configuración del mismo desde su dominio. En este marco, a partir de la categoría de cosmopolitica y del entendimiento del conocimiento indígena como epistemología, este trabajo reflexiona sobre el posicionamiento del antropóloga/o en ese ordenamiento desde donde se puede tejer entre redes de ontologías diferentes.

  7. Estructura, antiestructura y sistema-mundo en una comunidad alternativa. El caso de los “jipi-koguis” en la Sierra Nevada de Santa Marta

    Directory of Open Access Journals (Sweden)

    Jean Paul Sarrazin

    2016-01-01

    Full Text Available Utilizando los conceptos de estructura , antiestructura , liminalidad y sistema-mundo , este ensayo analiza algunas representaciones a propósito de los “jipi-koguis”, nombre que le ha sido atribuido a una comunidad hippie en la Sierra Nevada de Santa Marta (Co - lombia, fundada a principios de la década de los setenta cerca de un asentamiento indígena kogui. Este tipo de grupos se plan - tean como proyectos “por fuera de la estructura”, “antisistémi - cos”, “alternativos”, lo cual es sometido acá a un análisis crítico, ya que los sujetos que hacen parte de estos grupos pueden ser claramente identificados a través de roles y posiciones dentro de una estructura social. Por otro lado, en su búsqueda de cambios y admiración por una cierta diferencia, este tipo de proyectos pretenden inspirarse en “otras culturas” ―en este caso la indíge - na―, presuponiendo equivocadamente que estas están radical - mente separadas del sistema moderno occidental. Se demuestra además que los discursos e intencionalidades de los sujetos que buscan salirse del sistema occidental y capitalista no pueden en - tenderse por fuera de ese mismo sistema. Finalmente, argumen - tamos que este tipo de comunidades, aunque dicen oponerse a la estructura social, tienden a estructurarse ellas mismas a medi - da que pasa el tiempo, generalmente por razones económicas y políticas.

  8. Estudio de un brote epidémico de fiebre amarilla selvática en el pie de monte de La Sierra Nevada de Santa Marta, 1979

    Directory of Open Access Journals (Sweden)

    Hernando Vidales

    1981-12-01

    Full Text Available En 1979 se observó en Colombia una epidemia de fiebre amarilla selvática, en las estribaciones más bajas de la Sierra Nevada de Santa Marta, donde nunca antes se había registrado la enfermedad. Los casos ocurrieron en las cercanías de las ciudades de Valledupar y Santa Marta, por entonces infestadas con Aedes aegypti .Veinte de ellos fueron confirmados por examen histopatológico de hígado o por aislamiento de virus y en otros 36 se hizo un diagnóstico de presunción, con base en estudios clínicos, epidemiológicos y serológicos. Entre los primeros hubo 14 defunciones y entre los segundos 13. En las localidades urbanas del Brea se llevaron a cabo intensas campañas de lucha contra el A. aegyptiy de vacunación. No se registraron casos urbanos de la enfermedad. Los enfermos se infectaron en bosques estrechos de galería y en cafetales. donde previa y paralelamente se observó mortalidad en monos í Alouatta seniculus. El reconocimiento entomológico mostró en la región la presencia de 3 especies de Haemagogus, entre ellas H. janthinomys Con 745 mosquitos se hicieron 192 mezclas para intentar aislamiento de virus, habiéndose obtenido sólo uno positivo para fiebre amarilla, a partir de H. janthinomys. La epidemia descrita es un ejemplo mBs de la invasión del virus amarílico a nuevos "habitats" rurales,  con la consiguiente amenaza para las ciudades vecinas infestadas con A. aegypti, el riesgo de la urbanización del virus, lo cual exige la adopción inmediata de medidas para abatir el mosquito y para vacunar a la población expuesta.

  9. Simulated hydrologic responses to climate variations and change in the Merced, Carson, and American River basins, Sierra Nevada, California, 1900-2099 *

    Science.gov (United States)

    Dettinger, M.D.; Cayan, D.R.; Meyer, M.K.; Jeton, A.

    2004-01-01

    Hydrologic responses of river basins in the Sierra Nevada of California to historical and future climate variations and changes are assessed by simulating daily streamflow and water-balance responses to simulated climate variations over a continuous 200-yr period. The coupled atmosphere-ocean-ice-land Parallel Climate Model provides the simulated climate histories, and existing hydrologic models of the Merced, Carson, and American Rivers are used to simulate the basin responses. The historical simulations yield stationary climate and hydrologic variations through the first part of the 20th century until about 1975 when temperatures begin to warm noticeably and when snowmelt and streamflow peaks begin to occur progressively earlier within the seasonal cycle. A future climate simulated with business-as-usual increases in greenhouse-gas and aerosol radiative forcings continues those recent trends through the 21st century with an attendant +2.5??C warming and a hastening of snowmelt and streamflow within the seasonal cycle by almost a month. The various projected trends in the business-as-usual simulations become readily visible despite realistic simulated natural climatic and hydrologic variability by about 2025. In contrast to these changes that are mostly associated with streamflow timing, long-term average totals of streamflow and other hydrologic fluxes remain similar to the historical mean in all three simulations. A control simulation in which radiative forcings are held constant at 1995 levels for the 50 years following 1995 yields climate and streamflow timing conditions much like the 1980s and 1990s throughout its duration. The availability of continuous climate-change projection outputs and careful design of initial conditions and control experiments, like those utilized here, promise to improve the quality and usability of future climate-change impact assessments.

  10. Incorporating cold-air pooling into downscaled climate models increases potential refugia for snow-dependent species within the Sierra Nevada Ecoregion, CA.

    Directory of Open Access Journals (Sweden)

    Jennifer A Curtis

    Full Text Available We present a unique water-balance approach for modeling snowpack under historic, current and future climates throughout the Sierra Nevada Ecoregion. Our methodology uses a finer scale (270 m than previous regional studies and incorporates cold-air pooling, an atmospheric process that sustains cooler temperatures in topographic depressions thereby mitigating snowmelt. Our results are intended to support management and conservation of snow-dependent species, which requires characterization of suitable habitat under current and future climates. We use the wolverine (Gulo gulo as an example species and investigate potential habitat based on the depth and extent of spring snowpack within four National Park units with proposed wolverine reintroduction programs. Our estimates of change in spring snowpack conditions under current and future climates are consistent with recent studies that generally predict declining snowpack. However, model development at a finer scale and incorporation of cold-air pooling increased the persistence of April 1st snowpack. More specifically, incorporation of cold-air pooling into future climate projections increased April 1st snowpack by 6.5% when spatially averaged over the study region and the trajectory of declining April 1st snowpack reverses at mid-elevations where snow pack losses are mitigated by topographic shading and cold-air pooling. Under future climates with sustained or increased precipitation, our results indicate a high likelihood for the persistence of late spring snowpack at elevations above approximately 2,800 m and identify potential climate refugia sites for snow-dependent species at mid-elevations, where significant topographic shading and cold-air pooling potential exist.

  11. The 16 May 2005 Flood in Yosemite National Park--A Glimpse into High-Country Flood Generation in the Sierra Nevada

    Science.gov (United States)

    Dettinger, M.; Lundquist, J.; Cayan, D.; Meyer, J.

    2006-12-01

    On 16 May 2005, a Pacific storm drew warm, wet subtropical air into the Sierra Nevada, causing moderate rains and major flooding. The flood raised Hetch Hetchy and Tenaya Lake levels markedly and inundated large parts of Yosemite Valley, requiring evacuations and raising public-safety concerns in Yosemite National Park. This was the first major flood to be recorded by the high-country hydroclimatic network in the Park. Since 2001, scientists from US Geological Survey, Scripps Institution of Oceanography, California Department of Water Resources, National Park Service, and other institutions have developed the network of over 30 streamflow and 50 air-temperature loggers at altitudes ranging from 3000 m above sea level, and 8 snow-instrumentation sites measuring snow-water contents, snow depths, radiation, soil moisture, and temperatures in air, snow, and soil. The network documented flooding that derived its runoff mostly from high-altitude rainfall on soils already wet due to the onset of snowmelt a few days earlier. Air temperatures during the storm were above freezing up to altitudes of nearly 3000 m, so that rain fell to as high as 3000 m, compared with normal winter snowlines nearer 1500 m. Streams flooded below 3000 m, and above that altitude did not flood or contribute much to the flooding below. Meanwhile, no significant snow-water content changes were measured. Thus this flood resulted from rain-through-snow runoff rather than rain-on-snow melting. In the Park as a whole, about five times more catchment area received rain, rather than snow, during this storm than during typical cool winter storms. Because the flood was more a result of the large area that received rainfall than of melting snow, snowpack reductions that are expected if recent warming trends continue would not have reduced the flood. Instead, the opportunity for warm storms may increase if warming continues, in which case the potential for this kind of flooding will increase.

  12. Reproducción de Joturus pichardi y Agonostomus monticola(Mugiliformes: Mugilidae en ríos de la Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Pedro Eslava Eljaiek

    2011-12-01

    Full Text Available Para los mugílidos de agua dulce Joturus pichardi y Agonostomus monticola se han documentado aspectos ecológicos y de distribución, principalmente para las poblaciones de América Central, sin embargo, hay poca información disponible de sus aspectos reproductivos, especialmente en ambientes de agua dulce de Colombia. Por lo tanto para ambas especies se estudió la biología reproductiva en ríos de la Sierra Nevada de Santa Marta durante julio de 2005 y diciembre de 2006. En total, 14 especímenes de J. pichardi y 320 A. monticola fueron capturados. Proporción sexual, índice gonadosomático, talla media de madurez, fecundidad y diámetros de los ovocitos fueron evaluados. Se realizó un bioensayo para observar el efecto de la salinidad sobre la movilidad espermática y su posible relación con el área de desove de las especies. Estos mugílidos comparten un hábitat con características ecológicas similares, de corrientes fuertes y claras y zonas pedregosas. Indicadores de madurez gonadal y evidencias indirectas son presentados y con los cuales se comprueba que el periodo reproductivo se encuentra relacionado con los mayores valores de precipitación de la zona (septiembre a noviembre, así como, la migración catádroma de J. pichardi y A. monticola. Estas especies representan un potencial de cultivo, dado su alimentación basada en vegetales y macroinvertebrados, la calidad de su carne y las tallas que pueden alcanzar, por lo cual, se deben efectuar estudios más profundos que revelen mayor información sobre su comportamiento y reproducción en cautividad.Reproduction of Joturus pichardi and Agonostomus monticola (Mugiliformes: Mugilidae in rivers of the Sierra Nevada de Santa Marta, Colombia. The freshwater mugilids Joturus pichardi and Agonostomus monticola, have been documented on ecological and distribution aspects, mainly for Central American populations, nevertheless, little information is available on their reproductive aspects

  13. Efficient way back litters nutrient potential of a tropical forest of bank. Sierra Nevada of Santa Marta Colombia

    International Nuclear Information System (INIS)

    Fuentes Molina, Natalia; Rodriguez Barrios, Javier Alfredo

    2012-01-01

    In three representative forests along the River Gaira, (subtropical wet forest, subtropical moist forest and tropical thorn mount), were measured over six months (wet and dry seasons) fluxes of nitrogen and phosphorus through the litter. Concentrations of nutrients (nitrogen and phosphorus) in the litter were relatively similar in the three Nevada de Santa Marta Colombia. Fuentes, Rodriguez. vegetation types (1.71% n and 0.12% p for the subtropical moist forest, followed by the tropical thorn mount with 1.50% n and 0.10% p and the subtropical wet forest with 1.39% n and 0.08% p), with the most significant differences found for nitrogen, which is the major nutrient with the absolute maximum in the subtropical rain forest set in the middle stretch of the basin. The greatest returns on biomass and nutrients occurred in the subtropical moist forest and tropical thorn mount set in the middle and lower reaches of the basin. The leaves showed high concentration of n and consequently, given the high production values of the different fractions, a high potential return of n (78.6 kg ha-1 yr-1). The foliar p concentration showed a potential return of 4.9 kgha1yr-1 and high values of the indices of efficiency in their use (iev: 2888.5) and foliar resorption (ern: 98.2), was the nutrient most limiting.

  14. Airborne LiDAR analysis and geochronology of faulted glacial moraines in the Tahoe-Sierra frontal fault zone reveal substantial seismic hazards in the Lake Tahoe region, California-Nevada USA

    Science.gov (United States)

    Howle, James F.; Bawden, Gerald W.; Schweickert, Richard A.; Finkel, Robert C.; Hunter, Lewis E.; Rose, Ronn S.; von Twistern, Brent

    2012-01-01

    We integrated high-resolution bare-earth airborne light detection and ranging (LiDAR) imagery with field observations and modern geochronology to characterize the Tahoe-Sierra frontal fault zone, which forms the neotectonic boundary between the Sierra Nevada and the Basin and Range Province west of Lake Tahoe. The LiDAR imagery clearly delineates active normal faults that have displaced late Pleistocene glacial moraines and Holocene alluvium along 30 km of linear, right-stepping range front of the Tahoe-Sierra frontal fault zone. Herein, we illustrate and describe the tectonic geomorphology of faulted lateral moraines. We have developed new, three-dimensional modeling techniques that utilize the high-resolution LiDAR data to determine tectonic displacements of moraine crests and alluvium. The statistically robust displacement models combined with new ages of the displaced Tioga (20.8 ± 1.4 ka) and Tahoe (69.2 ± 4.8 ka; 73.2 ± 8.7 ka) moraines are used to estimate the minimum vertical separation rate at 17 sites along the Tahoe-Sierra frontal fault zone. Near the northern end of the study area, the minimum vertical separation rate is 1.5 ± 0.4 mm/yr, which represents a two- to threefold increase in estimates of seismic moment for the Lake Tahoe basin. From this study, we conclude that potential earthquake moment magnitudes (Mw) range from 6.3 ± 0.25 to 6.9 ± 0.25. A close spatial association of landslides and active faults suggests that landslides have been seismically triggered. Our study underscores that the Tahoe-Sierra frontal fault zone poses substantial seismic and landslide hazards.

  15. Problemática indígena « el ", , " ,, declaración conjunta de las cuatro organizaciones indígenas de la sierra nevada de santa marta para la interlocución con el estado y la sociedad nacional

    OpenAIRE

    Organización Wiwa Yugumaitm Bunkwanarrwa (owybt); Organización Indígena Kankwama (aik); Cor.federoeion Indígena Tayrona (eít); Organízaeión Gonawindua Tayrona (ogt)

    2014-01-01

    Este documento responde a las preocupaciones comunes de las cuatro organiz"acio..: nes representativas de los pueblos indígenas de la Sierra Nevada (OWYBT, OIK, CIT, OGT), a la hora de trazar el futuro del territorio que desde los inicios del mundo  les fue encomendado por los Padres y Madresespirituales.

  16. Holocene climate aridification trend and human impact interrupted by millennial- and centennial-scale climate fluctuations from a new sedimentary record from Padul (Sierra Nevada, southern Iberian Peninsula)

    Science.gov (United States)

    Ramos-Román, María J.; Jiménez-Moreno, Gonzalo; Camuera, Jon; García-Alix, Antonio; Anderson, R. Scott; Jiménez-Espejo, Francisco J.; Carrión, José S.

    2018-01-01

    Holocene centennial-scale paleoenvironmental variability has been described in a multiproxy analysis (i.e., lithology, geochemistry, macrofossil, and microfossil analyses) of a paleoecological record from the Padul Basin in Sierra Nevada, southern Iberian Peninsula. This sequence covers a relevant time interval hitherto unreported in the studies of the Padul sedimentary sequence. The ˜ 4700-year record has preserved proxies of climate variability, with vegetation, lake levels, and sedimentological change during the Holocene in one of the most unique and southernmost wetlands in Europe. The progressive middle and late Holocene trend toward arid conditions identified by numerous authors in the western Mediterranean region, mostly related to a decrease in summer insolation, is also documented in this record; here it is also superimposed by centennial-scale variability in humidity. In turn, this record shows centennial-scale climate oscillations in temperature that correlate with well-known climatic events during the late Holocene in the western Mediterranean region, synchronous with variability in solar and atmospheric dynamics. The multiproxy Padul record first shows a transition from a relatively humid middle Holocene in the western Mediterranean region to more aridity from ˜ 4700 to ˜ 2800 cal yr BP. A relatively warm and humid period occurred between ˜ 2600 and ˜ 1600 cal yr BP, coinciding with persistent negative North Atlantic Oscillation (NAO) conditions and the historic Iberian-Roman Humid Period. Enhanced arid conditions, co-occurring with overall positive NAO conditions and increasing solar activity, are observed between ˜ 1550 and ˜ 450 cal yr BP (˜ 400 to ˜ 1400 CE) and colder and warmer conditions occurred during the Dark Ages and Medieval Climate Anomaly (MCA), respectively. Slightly wetter conditions took place during the end of the MCA and the first part of the Little Ice Age, which could be related to a change towards negative NAO conditions

  17. Holocene climate aridification trend and human impact interrupted by millennial- and centennial-scale climate fluctuations from a new sedimentary record from Padul (Sierra Nevada, southern Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    M. J. Ramos-Román

    2018-01-01

    Full Text Available Holocene centennial-scale paleoenvironmental variability has been described in a multiproxy analysis (i.e., lithology, geochemistry, macrofossil, and microfossil analyses of a paleoecological record from the Padul Basin in Sierra Nevada, southern Iberian Peninsula. This sequence covers a relevant time interval hitherto unreported in the studies of the Padul sedimentary sequence. The  ∼  4700-year record has preserved proxies of climate variability, with vegetation, lake levels, and sedimentological change during the Holocene in one of the most unique and southernmost wetlands in Europe. The progressive middle and late Holocene trend toward arid conditions identified by numerous authors in the western Mediterranean region, mostly related to a decrease in summer insolation, is also documented in this record; here it is also superimposed by centennial-scale variability in humidity. In turn, this record shows centennial-scale climate oscillations in temperature that correlate with well-known climatic events during the late Holocene in the western Mediterranean region, synchronous with variability in solar and atmospheric dynamics. The multiproxy Padul record first shows a transition from a relatively humid middle Holocene in the western Mediterranean region to more aridity from  ∼  4700 to  ∼  2800 cal yr BP. A relatively warm and humid period occurred between  ∼  2600 and  ∼  1600 cal yr BP, coinciding with persistent negative North Atlantic Oscillation (NAO conditions and the historic Iberian–Roman Humid Period. Enhanced arid conditions, co-occurring with overall positive NAO conditions and increasing solar activity, are observed between  ∼  1550 and  ∼  450 cal yr BP (∼  400 to  ∼  1400 CE and colder and warmer conditions occurred during the Dark Ages and Medieval Climate Anomaly (MCA, respectively. Slightly wetter conditions took place during the end of

  18. Mercury Concentrations in Fish and Sediment within Streams are Influenced by Watershed and Landscape Variables including Historical Gold Mining in the Sierra Nevada, California

    Science.gov (United States)

    Alpers, C. N.; Yee, J. L.; Ackerman, J. T.; Orlando, J. L.; Slotton, D. G.; Marvin-DiPasquale, M. C.

    2015-12-01

    We compiled available data on total mercury (THg) and methylmercury (MeHg) concentrations in fish tissue and streambed sediment from stream sites in the Sierra Nevada, California, to assess whether spatial data, including information on historical mining, can be used to make robust predictions of fish fillet tissue THg concentrations. A total of 1,271 fish from five species collected at 103 sites during 1980-2012 were used for the modeling effort: 210 brown trout, 710 rainbow trout, 79 Sacramento pikeminnow, 93 Sacramento sucker, and 179 smallmouth bass. Sediment data were used from 73 sites, including 106 analyses of THg and 77 analyses of MeHg. The dataset included 391 fish (mostly rainbow trout) and 28 sediment samples collected explicitly for this study during 2011-12. Spatial data on historical mining included the USGS Mineral Resources Data System and publicly available maps and satellite photos showing the areas of hydraulic mine pits and other placer mines. Modeling was done using multivariate linear regression and multi-model inference using Akaike Information Criteria. Results indicate that fish THg, accounting for species and length, can be predicted using geospatial data on mining history together with other landscape characteristics including land use/land cover. A model requiring only geospatial data, with an R2 value of 0.61, predicted fish THg correctly with respect to over-or-under 0.2 μg/g wet weight (a California regulatory threshold) for 108 of 121 (89 %) size-species combinations tested. Data for THg in streambed sediment did not improve the geospatial-only model. However, data for sediment MeHg, loss on ignition (organic content), and percent of sediment less than 0.063 mm resulted in a slightly improved model, with an R2 value of 0.63. It is anticipated that these models will be useful to the State of California and others to predict areas where mercury concentrations in fish are likely to exceed regulatory criteria.

  19. Distribución espacial y temporal de larvas de Trichoptera (Insecta en el río Manzanares, Sierra Nevada de Santa Marta (Colombia

    Directory of Open Access Journals (Sweden)

    Daniel José Serna M

    2015-06-01

    Full Text Available Los insectos acuáticos son importantes como indicadores de calidad de aguas en ríos y arroyos. Uno de los grupos más abundantes son los Thichoptera, ellos juegan un papel importante por su papel funcional en los sistemas acuáticos. Por eso conocer su diversidad es prioritario. El objetivo de este estudio es conocer la estructura de la comunidad del orden Trichoptera y su dinámica espacio-temporal en relación con los microhábitats y algunas variables físicas y químicas, en la parte media y baja de la cuenca del río Manzanares (Sierra Nevada de Santa Marta, Colombia. Se muestrearon mensualmente ocho microhábitats entre agosto 2002 y febrero 2003, durante los periodos de lluvias y sequía. Se recolectaron 3 316 larvas, repartidas en tres subórdenes pertenecientes a 10 familias y 14 géneros; seis de estos géneros y una familia son los primeros registros para el departamento del Magdalena (Colombia. Los tricópteros presentaron la mayor abundancia y riqueza genérica en los microhábitats Hojarasca Corriente Lenta, Hojarasca Corriente Rápida y Piedra Corriente Rápida, donde Nectopsyche (28%, Leptonema (17% y Smicridea (15% fueron los géneros más predominantes. La estructura, y composición de los géneros del orden Trichoptera variaron en cada estación en función del régimen pluviométrico y las variables físicas y químicas presentadas en la localidad de estudio, evidenciando las menores abundancias y riqueza en los periodos de altas precipitaciones (octubre y noviembre y las mayores en épocas de precipitaciones bajas (diciembre, enero y febrero. De igual forma las estaciones con mayores valores de oxígeno disuelto y menores valores en temperatura y conductividad reportaron las mayores abundancias de tricópteros. Los tricópteros evidenciaron preferencias por microhábitats específicos, variación en su composición de acuerdo con los periodos climáticos y respuesta a los niveles de polución del río. Se recomienda

  20. High-resolution LIDAR and ground observations of snow cover in a complex forested terrain in the Sierra Nevada - implications for optical remote sensing of seasonal snow.

    Science.gov (United States)

    Kostadinov, T. S.; Harpold, A.; Hill, R.; McGwire, K.

    2017-12-01

    Seasonal snow cover is a key component of the hydrologic regime in many regions of the world, especially those in temperate latitudes with mountainous terrain and dry summers. Such regions support large human populations which depend on the mountain snowpack for their water supplies. It is thus important to quantify snow cover accurately and continuously in these regions. Optical remote-sensing methods are able to detect snow and leverage space-borne spectroradiometers with global coverage such as MODIS to produce global snow cover maps. However, snow is harder to detect accurately in mountainous forested terrain, where topography influences retrieval algorithms, and importantly - forest canopies complicate radiative transfer and obfuscate the snow. Current satellite snow cover algorithms assume that fractional snow-covered area (fSCA) under the canopy is the same as the fSCA in the visible portion of the pixel. In-situ observations and first principles considerations indicate otherwise, therefore there is a need for improvement of the under-canopy correction of snow cover. Here, we leverage multiple LIDAR overflights and in-situ observations with a distributed fiber-optic temperature sensor (DTS) to quantify snow cover under canopy as opposed to gap areas at the Sagehen Experimental Forest in the Northern Sierra Nevada, California, USA. Snow-off LIDAR overflights from 2014 are used to create a baseline high-resolution digital elevation model and classify pixels at 1 m resolution as canopy-covered or gap. Low canopy pixels are excluded from the analysis. Snow-on LIDAR overflights conducted by the Airborne Snow Observatory in 2016 are then used to classify all pixels as snow-covered or not and quantify fSCA under canopies vs. in gap areas over the Sagehen watershed. DTS observations are classified as snow-covered or not based on diel temperature fluctuations and used as validation for the LIDAR observations. LIDAR- and DTS-derived fSCA is also compared with

  1. Mesospheric OH layer altitude at midlatitudes: variability over the Sierra Nevada Observatory in Granada, Spain (37° N, 3° W)

    Science.gov (United States)

    García-Comas, Maya; José López-González, María; González-Galindo, Francisco; de la Rosa, José Luis; López-Puertas, Manuel; Shepherd, Marianna G.; Shepherd, Gordon G.

    2017-10-01

    The mesospheric OH layer varies on several timescales, primarily driven by variations in atomic oxygen, temperature, density and transport (advection). Vibrationally excited OH airglow intensity, rotational temperature and altitude are closely interrelated and thus accompany each other through these changes. A correct interpretation of the OH layer variability from airglow measurements requires the study of the three variables simultaneously. Ground-based instruments measure excited OH intensities and temperatures with high temporal resolution, but they do not generally observe altitude directly. Information on the layer height is crucial in order to identify the sources of its variability and the causes of discrepancies in measurements and models. We have used SABER space-based 2002-2015 data to infer an empirical function for predicting the altitude of the layer at midlatitudes from ground-based measurements of OH intensity and rotational temperature. In the course of the analysis, we found that the SABER altitude (weighted by the OH volume emission rate) at midlatitudes decreases at a rate of 40 m decade-1, accompanying an increase of 0.7 % decade-1 in OH intensity and a decrease of 0.6 K decade-1 in OH equivalent temperature. SABER OH altitude barely changes with the solar cycle, whereas OH intensity and temperature vary by 7.8 % per 100 s.f.u. and 3.9 K per 100 s.f.u., respectively. For application of the empirical function to Sierra Nevada Observatory SATI data, we have calculated OH intensity and temperature SATI-to-SABER transfer functions, which point to relative instrumental drifts of -1.3 % yr-1 and 0.8 K yr-1, respectively, and a temperature bias of 5.6 K. The SATI predicted altitude using the empirical function shows significant short-term variability caused by overlapping waves, which often produce changes of more than 3-4 km in a few hours, going along with 100 % and 40 K changes in intensity and temperature, respectively. SATI OH layer wave effects

  2. Hepatitis fulminante en la Sierra Nevada: Una forma de superinfección del virus delta con el virus de la hepatitis B.

    Directory of Open Access Journals (Sweden)

    Alvaro Villanueva

    1992-06-01

    Full Text Available Durante septiembre de 1980 a octubre de 1983, se realizó un estudio seroepidemiológico para hepatitis A y B, en 258 personas en una ciudad (Santa Marta población de 250.000 y tres pequeños municipios (Santa Rosalía, Julio Zawady y Aracataca, poblaciones de 768, 800 y 5.000 habitantes respectivamente. La presencia de hepatitis A se encontró en un 77 a 93% (IgG Hepatitis A. Hbs Ag o Anti-Hbs Ag en 30.5% de la población en dos municipios (Santa Rosalía y Julio Zawady, en 2.5% en el municipio de Aracataca y 48.5% en la ciudad de Santa Marta. La presencia del Agente Delta (Anti-delta en el suero se determinó también en estas mismas poblaciones, encontrándose ausente en la ciudad y uno de los municipios (Aracataca, en contraste con una prevalencia de 13.7% y 22% en Julio Zawady y Santa Rosalía (P: 0.0001. Se excluyeron por historia clínica, antecedentes de drogadicción, transfusiones, o prácticas homosexuales, como mecanismos de transmisión de los virus B y delta. En veinte pacientes con diagnóstico histopalógico de hepatitis fulminante y en quienes se descartaron otras etiologías se demostró la presencia serológica de los virus de la hepatitis By Delta. De estos veinte, diez provenían de Julio Zawady y los otros diez de Santa Rosalía. La evolución clínica de esta enfermedad fue indistinguible de otras causas de falla hepática aguda. La mortalidad de estas formas fulminantes de hepatitis alcanzaron hasta un 65%. Los corticoides no modificaron el curso de esta enfermedad. La población joven mostró mayor compromiso y peor diagnóstico (P:0.033. La hepatitis fulminante de la Sierra Nevada de Santa Marta es el resultado de la superinfección con el virus Delta sobre la infección virus B. La aparición simultánea de casos intrafamiliares sugiere una relación importante entre los grupos comprometidos, aunque la forma exacta de transmisión permanece aún desconocida.

  3. Characterization and testing of rock aggregates of the Santa Marta Batholith, (Colombia

    Directory of Open Access Journals (Sweden)

    Nancy Paola Figueroa Madero

    2014-12-01

    Full Text Available Aggregates of intrusive rocks are the major source of crushed fine and coarse aggregates for use in concrete in several countries and they have to meet a number of specifications relating to strength and durability. This research reports the evaluation of aggregates of granitoids and associated rocks of Santa Marta Batholith, Sierra Nevada de Santa Marta Massif, Colombia, based on petrographic analysis and mechanical and chemical acceptance tests. The strength and durability of a particular rock type depends on its intrinsic characteristic, thus petrographic analysis is very important to understand its mechanical and chemical properties. Numerous standard tests used to ensure aggregates meet the appropriate specifications; however, petrographic analysis represents the most valuable test for predicting the overall performance of concrete aggregates in any control test. Aggregates were analyzed to determine their petrographic, physical, mechanical and chemical properties. Samples were categorized as hornblendite, gabbro, quartzmonzodiorite, monzodiorite and monzonite groups. Among these, of the quartzmonzodiorite was the dominant group. Specific gravity indicates values in the range 2673-2956kg/m3. Water absorption values are in the range 0.908-1.194%. Aggregate impact values of samples (37.82 to 61.36% showed good soundness only for one of the aggregates, which are considered acceptable for use in the preparation of a good quality concrete. Values of Methylene Blue Adsorption reveal the organic matter content is below the threshold. Magnesium sulphate values ranged between 0.11 and 4.75% suggesting good resistance against chemical atmospheric agents. The compressive strength test shows values in the range 35.22-59.45MPa indicating that the geomechanical behavior of rock cylinders is satisfactory. The geomechanical behavior of rock tablets under flexion is also satisfactory for SMA-2 sample (16.53MPa, although not for SMA-6 and SMA-8 samples

  4. Sulfur concentration and isotopic variation in apatites from granitic to granodioritic plutons of a Cretaceous Cordilleran Batholith

    Science.gov (United States)

    Economos, R. C.

    2012-12-01

    Apatite is a common igneous accessory mineral with a high saturation temperature which can therefore crystallize over a significant portion of magmatic compositional space. Sulfur presents an opportunity to identify zoning in apatites. Unlike other trace elements, sulfur is relatively immobile in the apatite crystal structure and can be present in typical concentrations up to 1500 - 2000 ppm (or 0.5 to 1 wt% SO3). Sulfur concentration zoning in igneous apatites from ore producing magmatic systems has been identified (Streck and Dilles, 1998), but the interpretation of the cause of this zoning remains an open question. δ34S isotopic ratios of whole apatites have been used to track isotopic evolution associated with changes in magma fO2 and eruptive degassing (Rye, 2005). The presented work combines sulfur concentration mapping in zoned apatite crystals with in-situ SIMS 34S and 32S isotope measurements. Apatites were extracted from granite to granodiorite samples from the Cadiz Valley Batholith in the central Mojave Desert. This batholith is related to the pulse of Cretaceous Cordilleran magmatism that generated large batholiths in the Sierra Nevada and the Penninsular Ranges. The Mojave segment of the Cretaceous arc is unique in their construction into a full thickness of continental crust which exerted a strong influence on magmatic compositions. Apatite grains were mounted parallel to C axes, ground until grains were approximately bisected, and analyzed by Electron Microprobe at UCLA, for CaO, P2O5, SO3 and SiO2. Grains were surveyed and those yielding anomalous SO3 contents were investigated by micron-scale concentration mapping. Typical SO3 concentrations of apatites from all samples were ~0.2 wt%, while 8 to 10% of apatite grains from two samples contained cores with concentrations ranging up to 0.5 wt%. The sulfur zoning in these samples is oscillatory, in some grains representing 5 to 6 repetitions of high and low concentrations. Based on these textures

  5. Problemática indígena « el ", , " ,, declaración conjunta de las cuatro organizaciones indígenas de la sierra nevada de santa marta para la interlocución con el estado y la sociedad nacional

    Directory of Open Access Journals (Sweden)

    Organización Wiwa Yugumaitm Bunkwanarrwa (owybt

    2014-02-01

    Full Text Available Este documento responde a las preocupaciones comunes de las cuatro organiz"acio..: nes representativas de los pueblos indígenas de la Sierra Nevada (OWYBT, OIK, CIT, OGT, a la hora de trazar el futuro del territorio que desde los inicios del mundo  les fue encomendado por los Padres y Madresespirituales.

  6. Pb-Sr-Nd-O isotopic characterization of Mesozoic rocks throughout the northern end of the Peninsular Ranges batholith: Isotopic evidence for the magmatic evolution of oceanic arc–continental margin accretion during the Late Cretaceous of southern California

    Science.gov (United States)

    Kistler, Ronald W.; Wooden, Joseph L.; Premo, Wayne R.; Morton, Douglas M.

    2014-01-01

    contaminated magmatic arc. The Peninsular Ranges batholith magmatic arc was initially an oceanic arc built on Panthalassan lithosphere that eventually evolved into a continental margin magmatic arc collision zone, eventually overriding North American cratonic lithosphere. Our Pb-Sr-Nd data further suggest that the western arc rocks represent a nearshore or inboard oceanic arc, as they exhibit isotopic signatures that are more enriched than typical mid-ocean-ridge basalt (MORB). Isotopic signatures from the central zone are transitional and indicate that enriched crustal magma sources were becoming involved in the northern Peninsular Ranges batholith magmatic plumbing. As the oceanic arc–continental margin collision progressed, a mixture of oceanic mantle and continental magmatic sources transpired. Magmatic production in the northern Peninsular Ranges batholith moved eastward and continued to tap enriched crustal magmatic sources. Similar modeling has been previously proposed for two other western margin magmatic arcs, the Sierra Nevada batholith of central California and the Idaho batholith.Calculated initial Nd signatures at ca. 100 Ma for Permian–Jurassic and Proterozoic basement rocks from the nearby San Gabriel Mountains and possible source areas along the southwestern Laurentian margin of southern California, southwestern Arizona, and northern Sonora strongly suggest their involvement with deep crustal magma mixing beneath the eastern zones of the Peninsular Ranges batholith, as well as farther east in continental lithospheric zones.Last, several samples from the allochthonous, easternmost upper-plate zone, which are considerably younger (ca. 84 Ma) than any of the rocks from the northern Peninsular Ranges batholith proper, have even more enriched average Sri, 206Pbi, 208Pbi, and εNdisignatures of 0.7079, 19.344, 38.881, and −6.6, respectively, indicative of the most-evolved magma sources in the northern Peninsular Ranges batholith and similar to radioisotopic

  7. Idaho Batholith Study Area Isostatic Gravity Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 2 kilometer isostatic gravity grid for the Idaho batholith study area. Number of columns is 331 and number of rows is 285. The order of the data is from the lower...

  8. Idaho Batholith Study Area Bouguer Gravity Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 2 kilometer Bouguer gravity anomaly grid for the Idaho batholith study area. Number of columns is 331 and number of rows is 285. The order of the data is from the...

  9. Idaho Batholith Study Area Density Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 2 kilometer terrace-density grid for the Idaho batholith study area. Number of columns is 331 and number of rows is 285. The order of the data is from the lower...

  10. Evaluación biológica preliminar de extractos vegetales utilizados en la medicina tradicional de la Sierra Nevada deSanta Marta contra el veneno de la Bothrops asper

    Directory of Open Access Journals (Sweden)

    Willinton Barranco Pérez

    2013-10-01

    Full Text Available Title: Preliminary biological evaluation of plants extracts used in the Sierra Nevada de Santa Marta against the snake Bothrops asper venom.ResumenLa mordedura de serpientes constituye un problema de salubridad importante en muchos países tropicales y subtropicales, con un estimado de 2,5 millones de personas envenenadas cada año. En Colombia las especies Bothropsasper y Bothropsatrox son las causantes del 70 al 90 % de los accidentes registrados. Se estima que el 60% de estos accidentes son inicialmente tratados por curanderos tradicionales utilizando plantas medicinales en diferentes preparaciones. Este estudio evaluó la capacidad inhibitoria de cinco especies contra el efecto proteolítico y hemolítico indirecto inducido por el veneno de B. asper en ensayos in vitro.Las especies, que fueron seleccionadas de acuerdo a su uso en la medicina tradicional por parte de las comunidades campesinas de la Sierra Nevada de Santa Marta, fueron, Aristolochia máxima, Cissampelospareira, Equisetumbogotense, Mucunacfpruriens y una especie de la familia Asteraceae. La planta E. bogotense mostró los mayores porcentaje de inhibición contra la actividad de las fosfolipasas A2(42,29 %, así como la mayor precipitación de las proteínas en un rango de masas moleculares de 28,2 y 94,43 KDa. Al fraccionar el extracto de E. bogotense se obtuvieron cinco fracciones, las cuales presentaron un porcentaje de inhibición de 36,6 ± 1,07 a 46,1 ± 13,6. Adicionalmente se detectaron por métodos cualitativos núcleos como, alcaloides, esteroides y/o triterpenos, taninos, cumarinas y leucoantocianidinas. En estudio se reporta la actividad antiofídica en ensayos in vitro de la especie E. bogotense contra el veneno de la especie B.asper. (DUAZARY 2012 No. 2, 140 - 150AbstractIn Colombia the species Bothrops asper and Bothrops atrox are responsible for 70 to 90% of the snakebite accidents. Around 60% of these injuries are initially treated by traditional healers; they

  11. Abundancia relativa y uso de microhábitat de la rana Geobatrachus walkeri (Anura: Strabomantidae en dos hábitats en Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Vera Martínez Baños

    2011-06-01

    Full Text Available La rana Geobatrachus walkeri pertenece a un género monotípico y endémico del área de San Lorenzo, Sierra Nevada de Santa Marta, Colombia. La especie habita en el bosque secundario natural y en una plantación de pino (dominada por Pinus patula. Para comparar la abundancia relativa y el uso del microhábitat en estos dos hábitat y durante los períodos de máxima y mínima precipitación, se distribuyeron aleatoriamente 30 cuadrantes en cada bosque sobre los que se registraron el número de individuos y los microhábitats ocupados. Además se reconocieron otros aspectos de la historia natural mediante muestreo por encuentros casuales (VES, se incluye en los dos hábitats áreas no muestreadas por los cuadrantes. La mayor abundancia de ranas se obtuvo en la plantación de pino y durante la época de lluvias. El microhábitat más usado fue la hojarasca de pino. Geobatrachus walkeri es una especie exitosa en las plantaciones de pino, asociada permanentemente a su hojarasca en donde parece desarrollar todo su ciclo de vida. Las claras modificaciones derivadas de la introducción de las plantaciones de pino en el suelo y el agua, parecen no haber afectado la supervivencia y mantenimiento exitoso de esta especie categorizada como en peligro de extinción.Relative abundance and microhabitat use by the frog Geobatrachus walkeri (Anura:Strabomantidae in two habitats of Sierra Nevada de Santa Marta, Colombia. Geobatrachus walkeri belongs to a monotypic frog genus endemic to the San Lorenzo area, Sierra Nevada de Santa Marta, Colombia. This species has been categorized as endangered because of its small distribution area and the decline in the extent and quality of its habitat. It inhabits two forest types with different composition and structure, the native secondary forest and a pine plantation (dominated by Pinus patula. To compare the relative abundance and microhabitat use of this species in these habitat types, 30 quadrants/environment were

  12. Eficiencia de tres atrayentes alimenticios para la captura de Rhagoletis zoqui Bush, 1966 (Díptera: Tephritidae) y caracterización del sistema de producción del nogal de castilla (Juglans regia L.) en la Sierra Nevada de Puebla.

    OpenAIRE

    Aparicio del Moral, Yahana Michelle

    2014-01-01

    La mosca de la fruta Rhagoletis zoqui Bush, 1966 (Diptera: Tephritidae), es un insecto plaga asociado al nogal de Castilla (Juglans regia L.) que ocasiona pérdidas a los productores nogaleros en la Sierra Nevada de Puebla. En los últimos años se han incrementado las poblaciones de este insecto provocando daños importantes al fruto. No se dispone de información científica sobre los aspectos básicos para el control de este insecto en la región. En este trabajo, se evaluaron 3 atrayentes alimen...

  13. The role of volatile-saturation and adiabatic ascent of moderately hydrous melts on the formation of orbicules and comb layers in shallow subvolcanic conduits (Fisher Lake, Sierra Nevada).

    Science.gov (United States)

    McCarthy, A. J.; Müntener, O.

    2016-12-01

    Orbicules and comb layers are enigmatic features found sparsely distributed along plutonic contacts in a wide range of igneous environments. We provide new insights into the mechanisms responsible for the formation of these features by studying the spatial distribution, mineralogy and geochemistry of comb layers and orbicules from the Northern Sierra Nevada, Fisher Lake (USA). Over a range of studied comb textured layering, we show that the large majority of comb layers are cumulates formed by the initiation of plagioclase growth as a comb textured mineral. Plagioclase fractionation is followed by pyroxenes + oxides fractionation. Continuous crystal fractionation and conductive cooling from the host rock leads to amphibole saturation and the formation of late stage comb textured amphibole, leading to the formation of plagioclase- and plagioclase-amphibole comb textures. The lack of amphibole comb textures on orbicule rims as opposed to their widespread occurrence in comb layers, suggests that the presence of a thermal gradient plays an important role in diversifying comb textures. We propose that comb layers and orbicules are unique features which are controlled by the volatile content of ascending melts and ascent mechanisms. Thermodynamic calculations indicate that near-adiabatic decompression of water-undersaturated melts (ca. 4wt% H2O) through the crust will lead to superheating and dissolution of pre-existing minerals. Upon saturation of volatiles at shallow depth, degassing-induced undercooling of the decompressing melt will trigger heterogeneous nucleation of plagioclase on host rocks and remobilized xenoliths. The rarity of orbicules and comb layers in volcanic and plutonic rocks worldwide suggests that adiabatic decompression of moderately hydrous melts leading to superheating is a rare phenomena, with most arc melts ascending and cooling in small reservoirs throughout the crust, prior to emplacement at shallow depth as crystal-bearing magmas.

  14. An integrated approach to modeling changes in land use, land cover, and disturbance and their impact on ecosystem carbon dynamics: a case study in the Sierra Nevada Mountains of California

    Directory of Open Access Journals (Sweden)

    Benjamin M. Sleeter

    2015-06-01

    Full Text Available Increased land-use intensity (e.g. clearing of forests for cultivation, urbanization, often results in the loss of ecosystem carbon storage, while changes in productivity resulting from climate change may either help offset or exacerbate losses. However, there are large uncertainties in how land and climate systems will evolve and interact to shape future ecosystem carbon dynamics. To address this we developed the Land Use and Carbon Scenario Simulator (LUCAS to track changes in land use, land cover, land management, and disturbance, and their impact on ecosystem carbon storage and flux within a scenario-based framework. We have combined a state-and-transition simulation model (STSM of land change with a stock and flow model of carbon dynamics. Land-change projections downscaled from the Intergovernmental Panel on Climate Change’s (IPCC Special Report on Emission Scenarios (SRES were used to drive changes within the STSM, while the Integrated Biosphere Simulator (IBIS ecosystem model was used to derive input parameters for the carbon stock and flow model. The model was applied to the Sierra Nevada Mountains ecoregion in California, USA, a region prone to large wildfires and a forestry sector projected to intensify over the next century. Three scenario simulations were conducted, including a calibration scenario, a climate-change scenario, and an integrated climate- and land-change scenario. Based on results from the calibration scenario, the LUCAS age-structured carbon accounting model was able to accurately reproduce results obtained from the process-based biogeochemical model. Under the climate-only scenario, the ecoregion was projected to be a reliable net sink of carbon, however, when land use and disturbance were introduced, the ecoregion switched to become a net source. This research demonstrates how an integrated approach to carbon accounting can be used to evaluate various drivers of ecosystem carbon change in a robust, yet transparent

  15. An integrated approach to modeling changes in land use, land cover, and disturbance and their impact on ecosystem carbon dynamics: a case study in the Sierra Nevada Mountains of California

    Science.gov (United States)

    Sleeter, Benjamin M.; Liu, Jinxun; Daniel, Colin; Frid, Leonardo; Zhu, Zhiliang

    2015-01-01

    Increased land-use intensity (e.g. clearing of forests for cultivation, urbanization), often results in the loss of ecosystem carbon storage, while changes in productivity resulting from climate change may either help offset or exacerbate losses. However, there are large uncertainties in how land and climate systems will evolve and interact to shape future ecosystem carbon dynamics. To address this we developed the Land Use and Carbon Scenario Simulator (LUCAS) to track changes in land use, land cover, land management, and disturbance, and their impact on ecosystem carbon storage and flux within a scenario-based framework. We have combined a state-and-transition simulation model (STSM) of land change with a stock and flow model of carbon dynamics. Land-change projections downscaled from the Intergovernmental Panel on Climate Change’s (IPCC) Special Report on Emission Scenarios (SRES) were used to drive changes within the STSM, while the Integrated Biosphere Simulator (IBIS) ecosystem model was used to derive input parameters for the carbon stock and flow model. The model was applied to the Sierra Nevada Mountains ecoregion in California, USA, a region prone to large wildfires and a forestry sector projected to intensify over the next century. Three scenario simulations were conducted, including a calibration scenario, a climate-change scenario, and an integrated climate- and land-change scenario. Based on results from the calibration scenario, the LUCAS age-structured carbon accounting model was able to accurately reproduce results obtained from the process-based biogeochemical model. Under the climate-only scenario, the ecoregion was projected to be a reliable net sink of carbon, however, when land use and disturbance were introduced, the ecoregion switched to become a net source. This research demonstrates how an integrated approach to carbon accounting can be used to evaluate various drivers of ecosystem carbon change in a robust, yet transparent modeling

  16. Abundancia relativa y uso de microhábitat de la rana Geobatrachus walkeri (Anura: Strabomantidae en dos hábitats en Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Vera Martínez Baños

    2011-06-01

    Full Text Available La rana Geobatrachus walkeri pertenece a un género monotípico y endémico del área de San Lorenzo, Sierra Nevada de Santa Marta, Colombia. La especie habita en el bosque secundario natural y en una plantación de pino (dominada por Pinus patula. Para comparar la abundancia relativa y el uso del microhábitat en estos dos hábitat y durante los períodos de máxima y mínima precipitación, se distribuyeron aleatoriamente 30 cuadrantes en cada bosque sobre los que se registraron el número de individuos y los microhábitats ocupados. Además se reconocieron otros aspectos de la historia natural mediante muestreo por encuentros casuales (VES, se incluye en los dos hábitats áreas no muestreadas por los cuadrantes. La mayor abundancia de ranas se obtuvo en la plantación de pino y durante la época de lluvias. El microhábitat más usado fue la hojarasca de pino. Geobatrachus walkeri es una especie exitosa en las plantaciones de pino, asociada permanentemente a su hojarasca en donde parece desarrollar todo su ciclo de vida. Las claras modificaciones derivadas de la introducción de las plantaciones de pino en el suelo y el agua, parecen no haber afectado la supervivencia y mantenimiento exitoso de esta especie categorizada como en peligro de extinción.

  17. Transporte de materia orgánica a lo largo de un río tropical de montaña en la Sierra Nevada de Santa Marta (Colombia

    Directory of Open Access Journals (Sweden)

    Cesar Enrique Tamaris Turizo

    2015-09-01

    Full Text Available En los ríos tropicales, la materia orgánica es la principal fuente de energía para las comunidades que allí habitan. Las principales proporciones de materia orgánica se encuentra la materia orgánica particulada gruesa (MOPG y  la materia orgánica particulada fina (MOPF. Por lo anterior, en este trabajo se evaluó el transporte de la MOPG,  la MOPF y su relación con algunas variables físicas y químicas en tres tramos de un gradiente altitudinal de los 50 msnm hasta los 1700 msnm durante un ciclo diario en el río Gaira (Sierra Nevada de Santa Marta. Para lo cual se realizaron muestreos mensuales entre los meses de marzo a junio del 2008. Se detectaron diferencias significativas en la deriva de MOPG entre las estaciones, siendo la estación 2 (parte media durante el primer muestreo, la que registró los valores más altos reportados para todo el estudio (474 kg m-3 y la estación 3 mostró la menor biomasa derivante (0,26 kg m-3. La MOPF registró valores similares durante todos los muestreos (0,58 – 6,34 g m-3. Sin embargo, se detectaron diferencias significativas en los muestreos tres y cuatro. Con el aumento de las lluvias, descendió el transporte de  MOPG. Una relación inversa entre la velocidad del agua y el transporte de MOPG (rs = -0,70; n = 12; p < 0,05 se registró, mientras que la MOPF, presentó valores constantes. Los resultados de este trabajo coinciden parcialmente con lo registrado en la literatura, lo cual indica que las dinámicas de transporte de MO están relacionadas con las variaciones ambientales locales.

  18. Wildland fire management and air quality in the southern Sierra Nevada: using the Lion Fire as a case study with a multi-year perspective on PM(2.5) impacts and fire policy.

    Science.gov (United States)

    Schweizer, Don; Cisneros, Ricardo

    2014-11-01

    allow additional burning in an area with severe anthropogenic air pollution and where frequent widespread fire is both beneficial and inevitable. The more extensive air quality impacts documented with large high intensity fire may be averted by embracing the use of fire to prevent unwanted high intensity burns. A widespread increase in the use of fire for ecological benefit may provide the resiliency needed in Sierra Nevada forests as well as be the most beneficial to public health through the reduction of single dose exposure to smoke and limiting impacts spatially. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. A geological survey of the Lac du Bonnet batholith, Manitoba

    International Nuclear Information System (INIS)

    McCrank, G.F.D.

    1985-02-01

    This report presents the results of a geological survey of the Lac du Bonnet batholith in Manitoba. The survey consisted of field mapping of the lithologies and the joint systems throughout the batholith, and the examination of lineaments identified on aerial photographs and Landsat imagery. Petrographic descriptions and a map of the lithologies, an analysis of the fracture systems and a lineament map are presented. The results of various regional geophysical surveys were used as an aid to the interpretation of the batholith's contacts and in the interpretation of lineaments as possible faults. A comparison of the Lac du Bonnet Batholith with the Eye-Dashwa Lakes Pluton near Atikokan, Ontario is also presented

  20. A geological reconnaissance study of the Lac du Bonnet batholith

    International Nuclear Information System (INIS)

    Tammemagi, H.Y.; Kerford, P.S.; Requeima, J.C.; Temple, C.A.

    1980-02-01

    A geological reconnaissance survey was carried out of the Lac du Bonnet batholith, southeastern Manitoba, as part of the concept verification phase of the nuclear fuel waste disposal program for Canada. This report summarizes available geological information, presents the results of field mapping and discusses the geochemical analyses of rock samples. The geological and structural aspects of the batholith are described as well as its regional setting and possible genesis. (auth)

  1. Preliminary study of uranium favorability of the Boulder batholith, Montana

    International Nuclear Information System (INIS)

    Castor, S.B.; Robins, J.W.

    1978-01-01

    The Boulder batholith of southwestern Montana is a composite Late Cretaceous intrusive mass, mostly composed of quartz monzonite and granodiorite. This study was not restricted to the plutonic rocks; it also includes younger rocks that overlie the batholith, and older rocks that it intrudes. The Boulder batholith area has good overall potential for economic uranium deposits, because its geology is similar to that of areas that contain economic deposits elsewhere in the world, and because at least 35 uranium occurrences of several different types are present. Potential is greatest for the occurrence of small uranium deposits in chalcedony veins and base-metal sulfide veins. Three areas may be favorable for large, low-grade deposits consisting of a number of closely spaced chalcedony veins and enriched wall rock; the Mooney claims, the Boulder area, and the Clancy area. In addition, there is a good possibility of by-product uranium production from phosphatic black shales in the project area. The potential for uranium deposits in breccia masses that cut prebatholith rocks, in manganese-quartz veins near Butte, and in a shear zone that cuts Tertiary rhyolite near Helena cannot be determined on the basis of available information. Low-grade, disseminated, primary uranium concentrations similar to porphyry deposits proposed by Armstrong (1974) may exist in the Boulder batholith, but the primary uranium content of most batholith rocks is low. The geologic environment adjacent to the Boulder batholith is similar in places to that at the Midnite mine in Washington. Some igneous rocks in the project area contain more than 10 ppM U 3 O 8 , and some metasedimentary rocks near the batholith contain reductants such as sulfides and carbonaceous material

  2. Preliminary study of uranium favorability of the Boulder batholith, Montana

    Energy Technology Data Exchange (ETDEWEB)

    Castor, S.B.; Robins, J.W.

    1978-01-01

    The Boulder batholith of southwestern Montana is a composite Late Cretaceous intrusive mass, mostly composed of quartz monzonite and granodiorite. This study was not restricted to the plutonic rocks; it also includes younger rocks that overlie the batholith, and older rocks that it intrudes. The Boulder batholith area has good overall potential for economic uranium deposits, because its geology is similar to that of areas that contain economic deposits elsewhere in the world, and because at least 35 uranium occurrences of several different types are present. Potential is greatest for the occurrence of small uranium deposits in chalcedony veins and base-metal sulfide veins. Three areas may be favorable for large, low-grade deposits consisting of a number of closely spaced chalcedony veins and enriched wall rock; the Mooney claims, the Boulder area, and the Clancy area. In addition, there is a good possibility of by-product uranium production from phosphatic black shales in the project area. The potential for uranium deposits in breccia masses that cut prebatholith rocks, in manganese-quartz veins near Butte, and in a shear zone that cuts Tertiary rhyolite near Helena cannot be determined on the basis of available information. Low-grade, disseminated, primary uranium concentrations similar to porphyry deposits proposed by Armstrong (1974) may exist in the Boulder batholith, but the primary uranium content of most batholith rocks is low. The geologic environment adjacent to the Boulder batholith is similar in places to that at the Midnite mine in Washington. Some igneous rocks in the project area contain more than 10 ppM U/sub 3/O/sub 8/, and some metasedimentary rocks near the batholith contain reductants such as sulfides and carbonaceous material.

  3. Using hydrological modelling for a preliminary assessment of under-catch of precipitation in some Alpine Catchments of Sierra Nevada (Spain). Sensitivity to different conceptual approaches and spatio-temporal scale

    Science.gov (United States)

    Jimeno-Saez, Patricia; Pulido-Velazquez, David; Pegalajar-Cuellar, Manuel; Collados-Lara, Antonio-Juan; Pardo-Iguzquiza, Eulogio

    2017-04-01

    Precipitation (P) measurements show important biases due to under-catch, especially in windy conditions. Gauges modify the wind fields, producing important under-catch in solid P. In this work we intent to perform a global assessment of the under-catch phenomenon in some alpine catchments of Sierra Nevada Mountain Range (Spain) by using different conceptual hydrological models. They are based on the available information about daily natural streamflow and daily fields of P and temperature (T) in each catchment. We want to analyse long time periods (more than 20 years at daily scale) in order to obtain conclusions taking into account the stochastic behaviour of the natural streamflow and P and T variables. The natural streamflowin each basin has been obtained from the streamflow measurements in the gauges by making some simple mathematical operations to eliminate the anthropic influences. The daily climatic fieldswere estimated with spatial resolution of 1kmx1km by applying geostatistic techniques using data coming from 119climatic gauges existing in the area.We have considered to model options: Monthly and yearly variogram to characterize the spatial data correlation. The Elevation has been considered as secondary variable for the estimation. The analysis of the experimental data showed a linear relationhip between mean T and elevation. Therefore, we decided to apply a kriging with linear external drift to estimate the P and T fields. The mean daily P data show a quadratic relationship with the elevation. Different hypothesis have been considered to approach these P fields by applying kriging with linear drift, with quadratic drift, and regression kriging. A cross-validation analysis showed that the best approximation to the data is obtained with the kriging with linear drift. The P and T fields obtained with this technique were employed to feed different hydrological models in which different conceptual approaches of the hydrological processes related with the

  4. Riparian Birds - Sierra Nevada Foothill [ds303

    Data.gov (United States)

    California Natural Resource Agency — These data are summary statistics of abundances of birds counted within 100-m radius circles with 10-minute point counts at multiple sample points along 36 randomly...

  5. New data on barguzinsky granitoids age of the Angaro-Vitimsky batholith

    International Nuclear Information System (INIS)

    Budnikov, S.V.; Kovalenko, V.I.; Yarmolyuk, V.V.

    1995-01-01

    The age batholith rocks was studied by the Sm-Nd and U-Pb methods in terms of zircon. The boundary of masses being of Late carboniferous age of batholith rocks has been defined. Early and Middle Proterozoic age is possible for magmatic rocks of this part of batholith. 12 refs.; 3 refs.; 1 tab

  6. Magmatism and mineralization ages from northeast area of La Sierra de San Luis, Argentina

    International Nuclear Information System (INIS)

    Ulacco, Jose H

    2001-01-01

    Three igneous rock groups, characterized as pre, sin and post-kinematics, have intruded the crystalline basement of Sierra de San Luis, Argentina. The ore deposits are associated with Devonian to Carboniferous epizonal granite stocks and batholiths in an area underlain by metamorphic rocks. This granitoids are characterized as post-kinematics magmatism. Model lead ages on the ore deposits (338,8 - 292,1 Ma) are strongly supported by K-Ar ages of the intrusives. The bulk of the north Sierra de San Luis ore deposits are genetically related to late Carboniferous granite plutons. The ore bodies are tungsten veins with greisen envelopes, lead veins, epithermal fluorite veins and REE and Th deposit. A generalized scheme of ore bodies related to granites is proposed. The ore deposits and their lithotectonic setting are characteristic of Gondwana metallogenetic Epoch in the Sierra de San Luis (au)

  7. The Paranagua Batholith: proposition, age, petrogenetic considerations and tectonics implication

    International Nuclear Information System (INIS)

    Basei, M.A.S.; Reis Neto, J.M. dos

    1990-01-01

    The Paranagua Batholith comprises the major portion of the Costeiro Domain which is one of the three internal tectonic unities of the Joinville Massif in the southern Brazil (Mantiqueira Province). U-Pb in zircon (614 ± 10 Ma) and Rb-Sr whole rock isochron (543 ± 21 Ma) data are interpreted respectively as ages of the mineral crystallization and granitoid emplacement for the main igneous phase of the Paranagua Batholith. Sr, Pb and Nd analyses carried on this coarse biotite-microcline granitoid reveals its crustal melt origin with a source in the lower crust. It is here proposed the association of this Costeiro Domain (Parana), the Costeiro Complex (Sao Paulo) and Brusque Belt (or Tijucas Belt, Santa Catarina) as parts of the same collisional structure of the southern region of South America. (author)

  8. La participación como base del turismo comunitario y el manejo de los recursos de uso común. Sendero de Ritakuwas, Sierra Nevada de El Cocuy, Güicán y / o Chita. Boyacá, Colombia

    Directory of Open Access Journals (Sweden)

    Daniel Calderón Ramírez

    2014-11-01

    Full Text Available El objetivo principal de este estudio fue analizar el sendero que conduce al Ritakuwa Blanco, montaña de 5.330 m. s. n. m. ubicada en la Sierra Nevada de El Cocuy, Güicán y / o Chita, como un recurso de uso común (ruc. A través de este ruc se han establecido servicios turísticos y se han dado diferentes formas de participación por parte de las comunidades locales rurales, quienes lo usan y aprovechan. Por tanto, es necesaria una acción colectiva de los usuarios capaz de formular acuerdos o crear instituciones para el autogobierno y el uso sostenible del ruc, con el fin de evitar la tragedia de los bienes comunes2. Los prestadores de servicios turísticos decidieron participar en la planificación del ecoturismo debido a los estímulos y beneficios que pudieran llegar a recibir, como el fortalecimiento de la acción colectiva, la mayor autonomía y autogobierno para la sostenibilidad del sendero, la formalidad en la cadena de valor del turismo y la diversificación de los atractivos turísticos.

  9. Mining districts in the Carson Sink region, Nevada

    Science.gov (United States)

    Schrader, F.

    1947-01-01

    The region lies in an area of primarily sedimentary rocks which are principally Mesozoic and are tilted, folded, and faulted and cut by granular intrusives, and flooded by Tertiary lavas as shown on Figure 4. The Mesozoic sediments were strongly folded and invaded by granular intrusives at or about the time of the intrusion of the great Sierra Nevada batholith. The rocks are exposed chiefly in the mountain ranges and hills.The mountain ranges are mostly fault ranges with much of their structure monoclinical. Faulting in many instances has been prominent since the deposition of the Tertiary lavas and continues down to the present, as shown by fresh scarps and recent earthquake disturbances in the Stillwater and Augusta ranges and in general along the flaks of the various ranges by the tilted attitude of the lava flows and lake beds, and by the older lavas in general being tilted at steeper angles than the overlying lake beds. The faulting may be normal or overthrust.The faulting shown in the various mining districts as Fairview and Wonder may be regarded as indicating that of the region in general.In some parts of the region faulting is so young that it is still shown in the topographic forms as by trunctated gulches in the east base of the Stillwater range in Dixie Valley.As the writer in the present work had but small opportunity to examine the rocks excepting in the various mining districts many of which are located far apart, the accompanying geologic map (Fig. 4) is largely compiled from earlier reports of various authors in order to here present a geologic picture of the region. The portion to the north of Latitude 39°30’ is largely adapted from the 40th Parallel Survey and that to the south of the 39th parallel form the papers and reports by Buwalda, Clark, Merriam, Hill, Spurr, and the unpublished work of H. G. Ferguson of the U. S. Geological Survey on the Hawthorne and Tonopah quadrangles.

  10. Coexistence and mixing of magmas in the late precambrian Itaporanga batholith, State of Paraiba, Northeastern Brazil

    International Nuclear Information System (INIS)

    Mariano, G.; Sial, A.N.

    1990-01-01

    The Precambrian Cachoeirinha-Salgueiro Fold Belt (CSF) located in the western portion of the states of Pernambuco and Paraiba is intruded, in its northern portion, by several coarsely porphyritic potassic calc-alkalic batholiths. These batholiths were syntectonically emplaced in relation to the Brasiliano cycle (=Pan-African) and are commonly associated with potassium diorites suggesting coexistence and mixing between felsic and mafic magmas. In the Itaporanga batholith three petrographic domains were mapped. A hybrid zone characterized by intense mechanical mixing of granite to granodiorite and potassium diorite magmas is located towards the border of the batholith. A commingling zone where felsic porphyritic granite to granodiorite and potassium diorite rocks are individualized at outcrop scale is located towards the center of the batholith. Finally a felsic porphyritic facies occur in the hybrid zone. Similarity among chemical analyses of amphiboles from potassium dioritic enclaves of the Itaporanga batholith and from the potassium diorite stock east of it suggest a common source for both magmas. This hypothesis is corroborated by similar REE patterns for potassium dioritic enclaves of the Itaporanga batholith and for the potassium diorite stock. The batholith shows a well developed foliation which dips towards its core suggesting that the present level of exposure represents the root zone of a diapir, where intense interaction between felsic and mafic magmas took place. (author)

  11. Traverse across the Nelspruit batholith and the geology of the excursion route between Sabie and Witbank

    International Nuclear Information System (INIS)

    Robb, L.J.; Anhaeusser, C.R.

    1981-01-01

    A geologic survey was done on the traverse across the Nelspruit batholith and the geology of the excursion route between Sabie and Witbank. Rubidium isotopes, strontium 86 and strontium 87 were used to determine the rock age. The petrogenetic aspects relating to the Nelspruit batholith were also studied

  12. Magmatic constraints on localization of natural stone deposits in the Vehmaa rapakivi granite batholith, southwestern Finland

    Directory of Open Access Journals (Sweden)

    Olavi Selonen

    2011-08-01

    Full Text Available The 1580–1570 Ma old Vehmaa rapakivi granite batholith was studied with the aim to define the geological constraints for localization of natural stone deposits in the batholith. The batholith comprises four roughly concentric granite intrusions from the margin inwards: pyterlite, coarse-grained porphyritic rapakivi granite and two types of medium-grained porphyritic rapakivi granite. Also porphyry aplite and even-grained rapakivi granite occur. The batholith has intruded as a succession of pulses of subhorizontal sheet-like intrusions conceivably through repeated cauldron subsidence. Natural stone quarries are confined only to certain intrusions within the batholith. We show that the medium-grained porphyritic granite body in the centre of the batholith comprises two almost identical but different intrusions, with only slightly different appearances: the inner (IG and the outer (OG granite. The quarries are confined to the outer intrusion which has an appearance more attractive to the market than that of the inner intrusion. The localization of the natural stone deposits in the Vehmaa batholith is a result of the magmatic history of the batholith, producing intrusions of different appearances with different commercial potential.

  13. Granite Exfoliation, Cosumnes River Watershed, Somerset, California

    Science.gov (United States)

    Crockett, I. Q.; Neiss-Cortez, M.

    2015-12-01

    In the Sierra Nevada foothills of California there are many exposed granite plutons within the greater Sierra Nevada batholith. As with most exposed parts of the batholith, these granite slabs exfoliate. It is important to understand exfoliation for issues of public safety as it can cause rock slides near homes, roads, and recreation areas. Through observation, measuring, and mapping we characterize exfoliation in our Cosumnes River watershed community.

  14. Guide to Using Sierra

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Ryan Phillip [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Agelastos, Anthony Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Miller, Joel D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    Sierra is an engineering mechanics simulation code suite supporting the Nation's Nuclear Weapons mission as well as other customers. It has explicit ties to Sandia National Labs' workfow, including geometry and meshing, design and optimization, and visualization. Dis- tinguishing strengths include "application aware" development, scalability, SQA and V&V, multiple scales, and multi-physics coupling. This document is intended to help new and existing users of Sierra as a user manual and troubleshooting guide.

  15. Guide to Using Sierra

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Ryan Phillip; Agelastos, Anthony Michael; Miller, Joel D.

    2017-04-01

    Sierra is an engineering mechanics simulation code suite supporting the Nation's Nuclear Weapons mission as well as other customers. It has explicit ties to Sandia National Labs' workfow, including geometry and meshing, design and optimization, and visualization. Dis- tinguishing strengths include "application aware" development, scalability, SQA and V&V, multiple scales, and multi-physics coupling. This document is intended to help new and existing users of Sierra as a user manual and troubleshooting guide.

  16. Demography of the California spotted owl in the Sierra National Forest and Sequoia/Kings Canyon National Parks

    Science.gov (United States)

    George N. Steger; Thomas E. Munton; Kenneth D. Johnson; Gary P. Eberlein

    2002-01-01

    Nine years (1990–1998) of demographic data on California spotted owls (Strix occidentalis occidentalis) in two study areas on the western slopes of the Sierra Nevada—one in the Sierra National Forest (SNF), the other in Sequoia/Kings Canyon National Parks (SNP)—are summarized. Numbers of territorial owls fluctuated from 85 to 50 in SNF and 80 to 58...

  17. The diffuse seismicity of the Sierra Nevada of Santa Marta, the Perijá Range, and south of the La Guajira peninsula, Colombia and Venezuela: Result of the convergence between Caribbean plate and the South American margin during the Late Neogene?

    Science.gov (United States)

    Chicangana, G.; Pedraza, P.; Mora-paez, H.; Ordonez Aristizabal, C. O.; Vargas-Jimenez, C. A.; Kammer, A.

    2012-12-01

    A diffuse low deep microseismicity located overall between the Guajira peninsula and the Sierra Nevada de Santa Marta (SNSM) was registered with the recent installation (2008 to Present) of three seismological stations in northeastern Colombia by the Colombian Seismological Network (RSNC), but mainly with the Uribia station in (the) central region of La Guajira peninsula, The microseismicity is characterized by a great population of events with 1.2 Oca fault because with the GPS displacement analysis, neotectonics evidence found in faults traces associated to the Oca fault and the historical earthquake that affected the Colombian city of Santa Marta in 1834, lead us to conclude this. This is a big cortical fault that sets the limit between La Guajira peninsula and the SNSM. Its cortical characteristics were verified from geological data together with gravimetric and seismic exploration. The SNSM limits toward the southeast with the Cesar - Ranchería basin, and this basin in turn limits with the Perijá Range that is localized in the Colombia - Venezuela border. The SNSM, Cesar - Ranchería basin and Perijá Range limit toward the southwest with the Bucaramanga - Santa Marta fault (BSMF), the Oca fault toward the north, and Perijá - El Tigre fault toward the southeast defining a pyramidal orogenic complex. Using remote sensing images data with geological and regional geophysical information, we proposed that this orogenic complex was originated as a result of the Panama arc with the northwestern South America accretion. The final adjustment of the Caribbean plate (CP) between North America and South America during the Late Neogene produced the big cortical faults systems activation like Oca - Moron - El Pilar in Colombia and Venezuela toward the south of the Caribbean Plate (CP), and Motegua - Walton - Enriquillo - Plantain Garden toward the north of the CP. This situation was originated of a new subduction development of the Nazca - Cocos plates toward the south

  18. Magma interaction in the root of an arc batholith

    Science.gov (United States)

    Chapman, T.; Robbins, V.; Clarke, G. L.; Daczko, N. R.; Piazolo, S.

    2016-12-01

    Fiordland, New Zealand, preserves extensive Cretaceous arc plutons, emplaced into parts of the Delamerian/Ross Orogen. Dioritic to gabbroic material emplaced at mid to lower crustal levels are exposed in the Malaspina Pluton (c. 1.2 GPa) and the Breaksea Orthogneiss (c. 1.8 GPa). Distinct magmatic pulses can be mapped in both of these plutons consistent with cycles of melt advection. Relationships are consistent with predictions from lower crustal processing zones (MASH and hot zones) considered important in the formation of Cordilleran margins. Metamorphic garnet growth is enhanced along magmatic contacts, such as where hornblende gabbronorite is cut by garnet-clinopyroxene-bearing diorite. Such features are consistent with cycles of incremental emplacement, younger magma having induced localised garnet granulite metamorphism in wall rock of older material. Temperature estimates and microstructures preserved in garnet granulite are consistent with sub-solidus, water-poor conditions in both the Malaspina and Breaksea Orthogneiss. The extent and conditions of the metamorphism implies conditions and duration was incapable of partially melting older wall rock material. The nature of interactions in intermediate to basic compositions are assessed in terms of magma genesis in the Cretaceous batholith. Most of the upper crustal felsic I-type magmatism along the margin being controlled by high-pressure garnet-clinopyroxene fractionation.

  19. Reproduction, abundance, and population growth for a fisher (Pekania pennanti) population in the Sierra National Forest, California

    Science.gov (United States)

    Rick A. Sweitzer; Viorel D. Popescu; Reginald H. Barrett; Kathryn L. Purcell; Craig M. Thompson

    2015-01-01

    In the west coast region of the United States, fishers (Pekania pennanti) exist in 2 remnant populations—1 in northern California and 1 in the southern Sierra Nevada, California—and 3 reintroduced populations (western Washington, southern Oregon, and northeastern California). The West Coast Distinct Population Segment of fishers encompassing all of...

  20. Sierra Leone Journal of Biomedical Research

    African Journals Online (AJOL)

    MHRL

    Sierra Leone Journal of Biomedical Research. (A publication of the College of Medicine and Allied Health Sciences, University of Sierra Leone). ©Sierra Leone Journal .... was used to. She seemed to have had a change of mind after ingesting.

  1. Sierra Structural Dynamics Theory Manual

    Energy Technology Data Exchange (ETDEWEB)

    Reese, Garth M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-19

    Sierra/SD provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of structural systems. This manual describes the theory behind many of the constructs in Sierra/SD. For a more detailed description of how to use Sierra/SD , we refer the reader to Sierra/SD, User's Notes . Many of the constructs in Sierra/SD are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Sierra/SD are specific to our implementation. We try to be far more complete in those areas. The theory manual was developed from several sources including general notes, a programmer notes manual, the user's notes and of course the material in the open literature. This page intentionally left blank.

  2. Origin, Petrogenesis and radiometric age dating of Pichagchi Batholith (North West Iran)

    International Nuclear Information System (INIS)

    Kholghi, M.H.; Vossoughi Abedini, A.

    2004-01-01

    Pichagchi batholith, located in 35 Km southeast of Shahin Dez, northwest of Iran, is situated in Central Iran, cutting Paleozoic rocks. Absolute age determination for this batholith by K-Ar radiometric method gives 74.20 Ma. indicating Late Cretaceous-Paleocene time corresponding to lauramide orogeny. This batholith consists of quartz diorite, tonalite, granodiorite and quartz monzodiorite in which main mafic minerals are biotite and amphibole. Enclaves are mica schist and fine graind quartz diorite in various sizes. Sieve texture and zonation observed in plagioclase minerals indicate that the original magma has been produced by magma mixing of lower crust and upper mantle. Geochemistry study of the main elements shows that the batholith is calc-alkaline and meta luminous and A12O3, Na2O, K2O, FeO values are high where as MgO, CaO, MnO, P2O5, TiO2 are low. In addition, genetic parameters for this batholith is compatible with I-Type granites (Caledonian). Rare earth elements plotted in spider diagrams show that the average slope the curves is from K towards Cr (left to right), indicating partial melting. Depletion of compatible elements such as Ni, Cu, V and enrichment of incompatible elements imply that magma was not original and not initiated from mantle. Further mores trough of Nb could be interpreted by magma mixing with crustal materials or by subduction. Also trough of Ti and crest of Y elements show that the origin of the magma is I-type. Finally, Pichagchi batholith is orogenic and its tectonic setting is compatible with continental arc granitoids

  3. African Journals Online: Sierra Leone

    African Journals Online (AJOL)

    Sierra Leone Journal of Biomedical Research. The Sierra Leone Journal of Biomedical Research publishes papers in all fields of Medicine and Allied Health Sciences including Basic Medical Sciences, Clinical Sciences, Dental Sciences, Behavioural Sciences, Biomedical Engineering, Molecular Biology, Pharmaceutical ...

  4. P- and S-body wave tomography of the state of Nevada.

    Energy Technology Data Exchange (ETDEWEB)

    Preston, Leiph

    2010-04-01

    P- and S-body wave travel times collected from stations in and near the state of Nevada were inverted for P-wave velocity and the Vp/Vs ratio. These waves consist of Pn, Pg, Sn and Sg, but only the first arriving P and S waves were used in the inversion. Travel times were picked by University of Nevada Reno colleagues and were culled for inclusion in the tomographic inversion. The resulting tomographic model covers the entire state of Nevada to a depth of {approx}90 km; however, only the upper 40 km indicate relatively good resolution. Several features of interest are imaged including the Sierra Nevada, basin structures, and low velocities at depth below Yucca Mountain. These velocity structure images provide valuable information to aide in the interpretation of geothermal resource areas throughout the state on Nevada.

  5. 75 FR 76975 - 2015 Resource Pool-Sierra Nevada Region

    Science.gov (United States)

    2010-12-10

    ... and allocation criteria set forth in the Marketing Plan. Comment: Four commentors requested that, in... Western Area Power Administration (Western), a Federal power marketing administration of DOE, announces the Final 2015 Resource Pool allocations pursuant to its 2004 Power Marketing Plan (Marketing Plan...

  6. Fire history of coniferous riparian forests in the Sierra Nevada

    Science.gov (United States)

    K. Van de Water; M. North

    2010-01-01

    Fire is an important ecological process in many western U.S. coniferous forests, yet high fuel loads, rural home construction and other factors have encouraged the suppression of most wildfires. Using mechanical thinning and prescribed burning, land managers often try to reduce fuels in strategic areas with the highest fuel loads. Riparian forests, however, are often...

  7. Charcoal Increases Microbial Activity in Eastern Sierra Nevada Forest Soils

    Directory of Open Access Journals (Sweden)

    Zachary W. Carter

    2018-02-01

    Full Text Available Fire is an important component of forests in the western United States. Not only are forests subjected to wildfires, but fire is also an important management tool to reduce fuels loads. Charcoal, a product of fire, can have major impacts on carbon (C and nitrogen (N cycling in forest soils, but it is unclear how these effects vary by dominant vegetation. In this study, soils collected from Jeffrey pine (JP or lodgepole pine (LP dominated areas and amended with charcoal derived from JP or LP were incubated to assess the importance of charcoal on microbial respiration and potential nitrification. In addition, polyphenol sorption was measured in unamended and charcoal-amended soils. In general, microbial respiration was highest at the 1% and 2.5% charcoal additions, but charcoal amendment had limited effects on potential nitrification rates throughout the incubation. Microbial respiration rates decreased but potential nitrification rates increased over time across most treatments. Increased microbial respiration may have been caused by priming of native organic matter rather than the decomposition of charcoal itself. Charcoal had a larger stimulatory effect on microbial respiration in LP soils than JP soils. Charcoal type had little effect on microbial processes, but polyphenol sorption was higher on LP-derived than JP-derived charcoal at higher amendment levels despite surface area being similar for both charcoal types. The results from our study suggest that the presence of charcoal can increase microbial activity in soils, but the exact mechanisms are still unclear.

  8. Vulnerability of birds to climate change in California's Sierra Nevada

    OpenAIRE

    Rodney B. Siegel; Peter Pyle; James H. Thorne; Andrew J. Holguin; Christine A. Howell; Sarah Stock; Morgan W. Tingley

    2014-01-01

    In a rapidly changing climate, effective bird conservation requires not only reliable information about the current vulnerability of species of conservation concern, but also credible projections of their future vulnerability. Such projections may enable managers to preempt or reduce emerging climate-related threats through appropriate habitat management. We used NatureServe's Climate Change Vulnerability Index (CCVI) to predict vulnerability to climate change of 168 bird species that breed i...

  9. Lower crustal xenoliths, Chinese Peak lava flow, central Sierra Nevada.

    Science.gov (United States)

    Dodge, F.C.W.; Calk, L.C.; Kistler, R.W.

    1986-01-01

    This assemblage of pyroxenite, peridotite and mafic granulite xenoliths in the toe of a 10 m.y. trachybasalt flow remnant overlying late Cretaceous granitic rocks, indicates the presence of a mafic-ultramafic complex beneath this part of central California; orthopyroxenites, websterites and clinopyroxenites are dominant. A few of the xenoliths contain ovoid opaque patches that are apparently pseudomorphs after garnet and have pyralspite garnet compositions; using a garnet-orthopyroxene geobarometer, they indicate a lower crustal depth of approx 40 km. Abundant mafic granulites can be subdivided into those with Al2O3 = or 15% and showing considerable scatter on oxide variation diagrams. The high-alumina granulite xenoliths have relatively low 87Rb/86Sr but high 87Sr/86Sr, whereas the low-alumina and ultramafic xenoliths have a wide range of 87Rb/86Sr, but lower 87Sr/86Sr; the isotopic data indicate roughly the same age as that of overlying granitic plutons (approx 100 m.y.). However, the granitic rocks have initial 87Sr/86Sr ratios intermediate between those of the high-alumina and ultramafic xenoliths, suggesting that they result from the mixing of basaltic magma (represented by the ultramafic rocks) and crustal materials, with subsequent crystal fractionation.-R.A.H.

  10. The Jurassic-early Cretaceous Ilo batholith of southern coastal Peru: geology, geochronology and geochemistry

    Science.gov (United States)

    Boekhout, Flora; Sempere, Thierry; Spikings, Richard; Schaltegger, Urs

    2010-05-01

    The Ilo batholith (17°00 - 18°30 S) crops out in an area of about 20 by 100 km, along the coast of southern Peru. This batholith is emplaced into the ‘Chocolate‘ Formation of late Permian to middle Jurassic age, which consists of more than 1000 m of basaltic and andesitic lavas, with interbedded volcanic agglomerates and breccias. The Ilo Batholith is considered to be a rarely exposed fragment of the Jurassic arc in Peru. Our aim is to reconstruct the magmatic evolution of this batholith, and place it within the context of long-lasting magma genesis along the active Andean margin since the Paleozoic. Sampling for dating and geochemical analyses was carried out along several cross sections through the batholith that were exposed by post-intrusion eastward tilting of 20-30°. Sparse previous work postulates early to middle Jurassic and partially early Cretaceous emplacement, on the basis of conventional K/Ar and 40Ar/39Ar dating methods in the Ilo area. Twenty new U-Pb zircon ages (LA-ICP-MS and CA-ID-TIMS) accompanied by geochemical data suggests the Ilo batholith formed via the amalgamation of middle Jurassic and early Cretaceous, subduction-related plutons. Preliminary Hf isotope studies reveal a primitive mantle source for middle Jurassic intrusions. Additional Sr, Nd and Hf isotope analyses are planned to further resolve the source regions of different pulses of plutonic activity. We strongly suggest that batholith emplacement was at least partly coeval with the emplacement of the late Permian to middle Jurassic Chocolate Formation, which was deposited in an extensional tectonic regime. Our age results and geochemical signature fit into the scheme of episodic emplacement of huge amounts of subduction related magmatism that is observed throughout the whole Andean event, particularly during the middle Jurassic onset of the first Andean cycle (southern Peru, northern Chile and southern Argentina). Although the exact geodynamic setting remains to be precisely

  11. New monazite U-Pb age constraints on the evolution of the Paleoproterozoic Vaasa granitoid batholith, western Finland

    Directory of Open Access Journals (Sweden)

    A.K. Kotilainen

    2016-09-01

    Full Text Available The Vaasa batholith, western Finland, is a large, peraluminous granitoid pluton that crystallized at 1.88–1.87 Ga during the culmination of the Svecofennian orogeny. The batholith has gradual contacts, through metatexites and diatexites, with the enveloping metasedimentary rocks of the Bothnian Belt. We present ID-TIMS U-Pb age data on monazite from granitoids and xenoliths of the Vaasa batholith and combine these with published U–Pb zircon ages in order to shed further light on the evolution of the Vaasa batholith. The apparent monazite ages for seven of the examined samples are 1870–1863 Ma, and 1855±3 Ma for one further sample from the southern part of the batholith. Combined with pre-existing data, the monazite ages of the granitoids are 9 to 18 Ma (face values or 3 to 9 Ma (external errors considered younger than the U–Pb zircon crystallization ages from respective samples. Our new data suggest slow cooling for the Vaasa batholith – the closure/saturation temperature of the monazite U–Pb system was probably reached in ~10 m.y. after the crystallization of magmatic zircon in the examined rocks.

  12. Synthesis of petrographic, geochemical, and isotopic data for the Boulder batholith, southwest Montana

    Science.gov (United States)

    du Bray, Edward A.; Aleinikoff, John N.; Lund, Karen

    2012-01-01

    The Late Cretaceous Boulder batholith in southwest Montana consists of the Butte Granite and a group of associated smaller intrusions emplaced into Mesoproterozoic to Mesozoic sedimentary rocks and into the Late Cretaceous Elkhorn Mountains Volcanics. The Boulder batholith is dominated by the voluminous Butte Granite, which is surrounded by as many as a dozen individually named, peripheral intrusions. These granodiorite, monzogranite, and minor syenogranite intrusions contain varying abundances of plagioclase, alkali feldspar, quartz, biotite, hornblende, rare clinopyroxene, and opaque oxide minerals. Mafic, intermediate, and felsic subsets of the Boulder batholith intrusions are defined principally on the basis of color index. Most Boulder batholith plutons have inequigranular to seriate textures although several are porphyritic and some are granophyric (and locally miarolitic). Most of these plutons are medium grained but several of the more felsic and granophyric intrusions are fine grained. Petrographic characteristics, especially relative abundances of constituent minerals, are distinctive and foster reasonably unambiguous identification of individual intrusions. Seventeen samples from plutons of the Boulder batholith were dated by SHRIMP (Sensitive High Resolution Ion Microprobe) zircon U-Pb geochronology. Three samples of the Butte Granite show that this large pluton may be composite, having formed during two episodes of magmatism at about 76.7 ± 0.5 Ma (2 samples) and 74.7 ± 0.6 million years ago (Ma) (1 sample). However, petrographic and chemical data are inconsistent with the Butte Granite consisting of separate, compositionally distinct intrusions. Accordingly, solidification of magma represented by the Butte Granite appears to have spanned about 2 million year (m.y.). The remaining Boulder batholith plutons were emplaced during a 6-10 m.y. span (81.7 ± 1.4 Ma to 73.7 ± 0.6 Ma). The compositional characteristics of these plutons are similar to those

  13. Pluton emplacement and magmatic arc construction: A model from the Patagonian batholith

    Science.gov (United States)

    Bruce, Robert; Nelson, Eric; Weaver, Stephen

    1988-01-01

    A model of batholithic construction in Andean arcs and its applicability to possibly similar environments in the past is described. Age and compositional data from the Patagonian batholith of southern Chile show a long history of magmatism in any given area (total age range is 15 to 157 Ma), but different regions appear to have different magmatic starting ages. Furthermore, mafic rocks seem to be the oldest components of any given region. An assembly line model involving semicontinuous magmatism and uplift was outlined, which has implications for other terranes: uplift rates will be proportional to observed ranges in age, and total uplift will be proportional to the age of the oldest pluton in any given area. It is suggested that misleading results would be obtained if only small areas of similar terranes in the Archean were available for study.

  14. Termination of the Batholiths marine seismic experiment: the scientific method loses to hearsay

    Science.gov (United States)

    Hollister, L. S.

    2007-12-01

    The marine seismic component of the NSF-Continental Dynamics funded project Batholiths was terminated by Canadian authorities due to environmental concerns. Socioeconomic benefits of the project were not taken into account, nor were findings by the National Research Council on effects of ocean noise on marine mammal populations. The marine seismic component of Batholiths was to have been done using sound from airguns towed behind the R/V Langseth in order to seismically image the geologic structures below the Coast Mountains of British Columbia. The project was nearly identical in timing, location, and scope to the ACCRETE project, which was successfully permitted and done in the early fall of 1994, with no detected or known damage to the environment. However, what changed in the last 13 years was a dramatic increase of concern by eNGOs (environmental non- government organizations) that airguns produced sound that might be harmful to marine species, marine mammals in particular. The marine noise concerns were amplified by eNGO agendas and campaigns to prevent oil exploration along continental margins and to shut down naval exercises involving sonar to detect submarines. Compared to these agendas, Batholiths was an easy target because the PIs (Principal Investigators) did not have the manpower or financial or legal resources (in contrast to the Navy and oil companies) to push back against an organized campaign set on stopping Batholiths. The main concern used to mobilize public opinion against Batholiths was that, if we were permitted, then oil exploration in the nearby region would be permitted; and, if oil were found, drilling would proceed: the slippery slope argument. Thus, by stopping Batholiths with the speculation that airgun noise, as used in a marine seismic study, might damage marine life, the eNGOs believe they have stopped oil exploration in British Columbia coastal waters. It is widely recognized that everything was done right to get the permits for

  15. The geochronology of uranium deposits in the Great Bear batholith, Northwest Territories

    International Nuclear Information System (INIS)

    Miller, R.G.

    1982-01-01

    The oldest uranium mineralisation found in the Great Bear batholith during this study may be hydrothermal pitchblende-hematite veins at Hottah Lake. Their apparent age of 2058 +- 34 Ma can also be explained by the contamination of deposits only 440 +- 57 Ma old, which is the age of pitchblende veins nearby. Numerous pendants of metamorphosed, uraninite-bearing 'black sand' placers in a north-trending belt west of the Wopmay Fault are 1860 +- 20 Ma old, the age of the granites that intrude them. Mineralisation at Echo Bay is from 1500 +- 10 to 1424 +- 29 Ma old, and extends up to 30 km north and 40 km south of Echo Bay. The JD claims contain small quartz vein deposits dated at 535 +- 164 and 1092 +- 115 Ma. At Mountain Lake, pitchblende in Helikian sandstones overlying the batholith is 1076 +- 96 Ma old. Polymetallic veinlets at Mazenod Lake are 457 +- 26 Ma old. Pitchblende in a giant quartz vein at the Rayrock mine is 511 +- 86 Ma old. Small pitchblende veins east of the batholith along the Coppermine River are between 400 and 660 Ma old. All the deposits are either between approximately 395 and 660 Ma old, or indicate remobilization during this interval. These events may be related to a marine transgression and regression approximately 600 and 350 Ma ago, respectively

  16. Sierra Pacific Power Company Alturas Transmission Line Project, Final Environmental Impact Report/Environmental Impact Statement. Volume 3: Appendices

    International Nuclear Information System (INIS)

    1995-11-01

    Sierra Pacific Power Company has proposed the construction and operation of a 345,000 volt overhead electric power transmission line from Alturas, California to Reno, Nevada. This Environmental Impact Report/Environmental Impact Statement will assess the potential environmental impacts of the proposed project and alternatives. This report contains Appendices A--I which contain the following: glossary/abbreviations; scoping report; structure coordinate summary; air quality; biological resources; geology; noise; visual contrast rating forms; and cultural resources

  17. Modeling interfacial fracture in Sierra.

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Arthur A.; Ohashi, Yuki; Lu, Wei-Yang; Nelson, Stacy A. C.; Foulk, James W.,; Reedy, Earl David,; Austin, Kevin N.; Margolis, Stephen B.

    2013-09-01

    This report summarizes computational efforts to model interfacial fracture using cohesive zone models in the SIERRA/SolidMechanics (SIERRA/SM) finite element code. Cohesive surface elements were used to model crack initiation and propagation along predefined paths. Mesh convergence was observed with SIERRA/SM for numerous geometries. As the funding for this project came from the Advanced Simulation and Computing Verification and Validation (ASC V&V) focus area, considerable effort was spent performing verification and validation. Code verification was performed to compare code predictions to analytical solutions for simple three-element simulations as well as a higher-fidelity simulation of a double-cantilever beam. Parameter identification was conducted with Dakota using experimental results on asymmetric double-cantilever beam (ADCB) and end-notched-flexure (ENF) experiments conducted under Campaign-6 funding. Discretization convergence studies were also performed with respect to mesh size and time step and an optimization study was completed for mode II delamination using the ENF geometry. Throughout this verification process, numerous SIERRA/SM bugs were found and reported, all of which have been fixed, leading to over a 10-fold increase in convergence rates. Finally, mixed-mode flexure experiments were performed for validation. One of the unexplained issues encountered was material property variability for ostensibly the same composite material. Since the variability is not fully understood, it is difficult to accurately assess uncertainty when performing predictions.

  18. Ignimbrites to batholiths: integrating perspectives from geological, geophysical, and geochronological data

    Science.gov (United States)

    Lipman, Peter W.; Bachmann, Olivier

    2015-01-01

    Multistage histories of incremental accumulation, fractionation, and solidification during construction of large subvolcanic magma bodies that remained sufficiently liquid to erupt are recorded by Tertiary ignimbrites, source calderas, and granitoid intrusions associated with large gravity lows at the Southern Rocky Mountain volcanic field (SRMVF). Geophysical data combined with geological constraints and comparisons with tilted plutons and magmatic-arc sections elsewhere are consistent with the presence of vertically extensive (>20 km) intermediate to silicic batholiths (with intrusive:extrusive ratios of 10:1 or greater) beneath the major SRMVF volcanic loci (Sawatch, San Juan, Questa-Latir). Isotopic data require involvement of voluminous mantle-derived mafic magmas on a scale equal to or greater than that of the intermediate to silicic volcanic and plutonic rocks. Early waxing-stage intrusions (35–30 Ma) that fed intermediate-composition central volcanoes of the San Juan locus are more widespread than the geophysically defined batholith; these likely heated and processed the crust, preparatory for ignimbrite volcanism (32–27 Ma) and large-scale upper-crustal batholith growth. Age and compositional similarities indicate that SRMVF ignimbrites and granitic intrusions are closely related, but the extent to which the plutons record remnants of former magma reservoirs that lost melt to volcanic eruptions has been controversial. Published Ar/Ar-feldspar and U-Pb-zircon ages for plutons spatially associated with ignimbrite calderas document final crystallization of granitoid intrusions at times indistinguishable from the tuff to ages several million years younger. These ages also show that SRMVF caldera-related intrusions cooled and solidified soon after zircon crystallization, as magma supply waned. Some researchers interpret these results as recording pluton assembly in small increments that crystallized rapidly, leading to temporal disconnects between

  19. Relationships between the Brook Street Terrane and Median Tectonic Zone (Median Batholith) : evidence from Jurassic conglomerates

    International Nuclear Information System (INIS)

    Tulloch, A.J.; Kimbrough, D.L.; Landis, C.A.; Mortimer, N.; Johnston, M.R.

    1999-01-01

    U-Pb zircon ages of 237-180 Ma and c. 280 Ma of seven granitoid clasts from the Rainy River Conglomerate which lies within the eastern Median Tectonic Zone (Median Batholith) in Nelson, and the Barretts Formation of the Brook Street Terrane in Southland, constrain the depositional ages of both units to be no older than c. 180-200 Ma (Early Jurassic). The minimum age of the Rainy River Conglomerate is constrained by the 147 +2 -1 Ma (Latest Jurassic) emplacement age of the One Mile Gabbronorite (new name: previously western Buller Diorite). The ages and chemistry of five of the granitoid clasts are broadly compatible with derivation from rocks that are now represented by Triassic plutons of the Median Tectonic Zone (Median Batholith), although ages as young as 180 Ma are slightly outside the range of the latter as currently exposed in New Zealand. The age (273-290 Ma, 237 +/- 3 Ma) and chemistry of the other two clasts (one each from Rainy River Conglomerate and Barretts Formation) suggest derivation from the Brook Street Terrane. Similarity in stratigraphic age, depositional characteristics, granitoid clast ages and composition between Rainy River Conglomerate and Barretts Formation suggests that they are broadly correlative and collectively overlapped a combined Brook Street Terrane - Median Batholith (MTZ) before the Late Jurassic (147 +2 -1 Ma). Sedimentary overlap may also have continued across to Middle Jurassic conglomeratic strata in the Murihiku Terrane to the east of the Brook Street Terrane. A U-Pb zircon age of 261 +/- 2 Ma is reported for Pourakino Trondhjemite of the Brook Street Terrane. (author). 56 refs., 10 figs., 4 tabs

  20. South-Tibetan partially molten batholiths: geophysical characterization and petrological assessment of their origin

    Science.gov (United States)

    Hetényi, G.; Pistone, M.; Nabelek, P. I.; Baumgartner, L. P.

    2017-12-01

    Zones of partial melt in the middle crust of Lhasa Block, Southern Tibet, have been geophysically observed as seismically reflective "bright spots" in the past 20 years. These batholiths bear important relevance for geodynamics as they serve as the principal observation at depth supporting channel-flow models in the Himalaya-Tibet orogen. Here we assess the spatial abundance of and partial melt volume fraction within these crustal batholiths, and establish lower and upper estimate bounds using a joint geophysical-petrological approach.Geophysical imaging constrains the abundance of partial melt zones to 5.6 km3 per surface-km2 on average (minimum: 3.1 km3/km2, maximum: 7.6 km3/km2 over the mapped area). Physical properties detected by field geophysics and interpreted by laboratory measurements constrain the amount of partial melt to be between 5 and 26 percent.We evaluate the compatibility of these estimates with petrological modeling based on geotherms, crustal bulk rock compositions and water contents consistent with the Lhasa Block. These simulations determine: (a) the physico-chemical conditions of melt generation at the base of the Tibetan crust and its transport and emplacement in the middle crust; (b) the melt percentage produced at the source, transported and emplaced to form the observed "bright spots". Two main mechanisms are considered: (1) melting induced by fluids produced during mineral dehydration reactions in the underthrusting Indian lower crust; (2) dehydration-melting reactions caused by heating within the Tibetan crust. We find that both mechanisms demonstrate first-order match in explaining the formation of the partially molten "bright spots". Thermal modelling shows that the Lhasa Block batholiths have only small amounts of melt and only for geologically short times (features of the geodynamic evolution. Their transience excludes both long-distance and long-lasting channel flow transport in Tibet.

  1. Late-stage alteration and tin-tungsten mineralization in the Khuntan Batholith, northern Thailand

    Science.gov (United States)

    Yokart, B.; Barr, S. M.; Williams-Jones, A. E.; Macdonald, A. S.

    2003-07-01

    The Khuntan Batholith is part of the Triassic-Jurassic eastern marginal belt of the Northern Thailand Granite Province. Most of the batholith consists of coarse-grained, porphyritic to megacrystic biotite-muscovite granite (Huai Mae San unit). However, the southeastern part, called the Muang Yao unit, consists of coarse- to medium-grained muscovite and muscovite-tourmaline granite and is associated with Sn-W mineralization. The Huai Mae San granite has S-type petrological features typical of batholiths in the eastern marginal belt, which formed in a syn-collisional setting. The more silicic Muang Yao granite differs chemically from felsic S-type granite, for example in extreme Rb-Y-Nb enrichment and Ba-Sr-Zr depletion, probably as a result of late-stage fluid alteration. Vein-hosted deposits of cassiterite, scheelite, and wolframite associated with minor sulfides occur in both the Muang Yao granite and adjacent metamorphic rocks. Fluid-inclusion studies indicate that both aqueous and aqueous-carbonic fluids of low salinity (0-8 wt% equiv. NaCl) were involved in vein formation, and were subject to pressure fluctuation between essentially lithostatic and hydrostatic conditions. Dilution of magmatic hydrous fluid by influx of meteoric water may explain the anomalously low salinity. Oxygen isotope data support a primary magmatic origin for the fluid, and indicate temperatures of ca. 400 °C for ore deposition. The three vein-type Sn-W deposits of this study represent a spectrum from an endogranite vein system to proximal-intermediate vein systems of magmatic-hydrothermal origin.

  2. Geophysical exploration for uranium in Suryamalai batholith, Salem District, Tamil Nadu, India

    Energy Technology Data Exchange (ETDEWEB)

    Anantharaman, K B; Sethuram, S [Department of Atomic Energy, Hyderabad (India). Atomic Minerals Div.

    1984-08-01

    Abnormally radioactive granitoids are targets of uranium exploration because they can be the source for uranium deposits as well as the hosts. Significant uranium mineralization is known to occur northwest of Suryamalai granite batholith at Kullampatti situated 40 km southwest of Salem. This paper embodies the geophysical exploration for uranium, using results of magnetic and radiometric methods. The investigations revealed that uranium mineralization is structurally controlled and such structures have magnetic expression. Incidentally, correlation of anomalous content of W with U is also brought to light.

  3. Early Cretaceous dextral transpressional deformation within the Median Batholith, Stewart Island, New Zealand

    International Nuclear Information System (INIS)

    Allibone, A.H.; Tulloch, A.J.

    2008-01-01

    The character, timing, and significance of deformation within the Median Batholith has been debated since at least 1967, with allochthonous and autochthonous models proposed to account for internal variations in the character of the batholith. Stewart Island provides excellent exposures of intrabatholithic structures, allowing many aspects of the deformation history within the batholith to be analysed, far removed from the effects of later deformation related to the current plate boundary. Median Batholith rocks in northern and central Stewart Island are deformed by three major structures: the Freshwater Fault System, Escarpment Fault, and Gutter Shear Zone. Lineation orientations, Al in hornblende geobarometry, and Ar-Ar thermochronology indicate up to c. 7 km of NNE-directed uplift of the hanging wall of the Escarpment Fault between c. 110 and 105 Ma. Unlike the Escarpment Fault, a wide range of mineral elongation lineation orientations, including many oblique to the strike and dip of related foliations, characterise both the Gutter Shear Zone and Freshwater Fault System. Lineation and limited sense of shear data indicate dextral-reverse movement on both structures during development of their dominant ductile fabrics. Crosscutting and intrusive relationships indicate movement on the Freshwater Fault System after c. 130 Ma and on the Gutter Shear Zone between 120 and 112 Ma. The amount of movement on the Freshwater Fault System and Gutter Shear Zone remains largely unconstrained. However, the 342 ± 24 Ma age of a granite clast in a Paterson Group lithic tuff horizon at Abrahams Bay overlaps that of Carboniferous plutons in the block immediately south of the Freshwater Fault System, implying that the Paterson Group is little displaced from the basement rocks through which it was erupted. The three structures mapped on Stewart Island form part of a narrow transpressional mobile belt active within the Jurassic-Cretaceous arc on the outboard margin of the Western

  4. Paleomagnetic contributions to the Klamath Mountains terrane puzzle-a new piece from the Ironside Mountain batholith, northern California

    Science.gov (United States)

    Mankinen, Edward A.; Gromme, C. Sherman; Irwin, W. Porter

    2013-01-01

    We obtained paleomagnetic samples from six sites within the Middle Jurassic Ironside Mountain batholith (~170 Ma), which constitutes the structurally lowest part of the Western Hayfork terrane, in the Klamath Mountains province of northern California and southern Oregon. Structural attitudes measured in the coeval Hayfork Bally Meta-andesite were used to correct paleomagnetic data from the batholith. Comparing the corrected paleomagnetic pole with a 170-Ma reference pole for North America indicates 73.5° ± 10.6° of clockwise rotation relative to the craton. Nearly one-half of this rotation may have occurred before the terrane accreted to the composite Klamath province at ~168 Ma. No latitudinal displacement of the batholith was detected.

  5. Geology, petrography, Geochemistry, and geochronology of the old granite batholith between Quen and Safaga, eastern desert, Egypt. Vol. 3

    International Nuclear Information System (INIS)

    Attawiya, M.Y.; Nossair, L.M.; El-Debeiky, A.; Ragab, A.I.

    1996-01-01

    A suite of tonalite-granodiorite and monzogranite forms a huge old granite batholith between qena and Safaga, Eastern Desert, Egypt. The batholith was originated from the fractional crystallization of a peraluminous calk-alkaline magma rich in silica and of low potassium content. It is developed in an island arc tectonic setting. The rocks forming the batholith are depleted in both U and Th elements. However, a gradual increase in these two elements from tonalite to monzogranite was observed. Zircon and sphene are responsible for U and Th contents in these rocks. Rh/Sr isotope age determination reported an age of 632.8 ± 4.6 Ma for these old granitoids. The low initial 87 Sr/ 86 Sr ratio in these rocks suggested their mantle origin or derivation from lower crustal materials with low Rb/Sr ratios and short residence in the crust. 10 figs., 5 tabs

  6. Geology, petrography, Geochemistry, and geochronology of the old granite batholith between Quen and Safaga, eastern desert, Egypt. Vol. 3.

    Energy Technology Data Exchange (ETDEWEB)

    Attawiya, M Y; Nossair, L M; El-Debeiky, A [Nuclear Materials Authority, Cairo, (Egypt); Ragab, A I [Ain Sahms Univ., Cairo, (Egypt)

    1996-03-01

    A suite of tonalite-granodiorite and monzogranite forms a huge old granite batholith between qena and Safaga, Eastern Desert, Egypt. The batholith was originated from the fractional crystallization of a peraluminous calk-alkaline magma rich in silica and of low potassium content. It is developed in an island arc tectonic setting. The rocks forming the batholith are depleted in both U and Th elements. However, a gradual increase in these two elements from tonalite to monzogranite was observed. Zircon and sphene are responsible for U and Th contents in these rocks. Rh/Sr isotope age determination reported an age of 632.8 {+-} 4.6 Ma for these old granitoids. The low initial{sup 87} Sr/{sup 86} Sr ratio in these rocks suggested their mantle origin or derivation from lower crustal materials with low Rb/Sr ratios and short residence in the crust. 10 figs., 5 tabs.

  7. Hydrogeologic characteristics of domains of sparsely fractured rock in the granitic Lac Du Bonnet Batholith, southeastern Manitoba, Canada

    International Nuclear Information System (INIS)

    Stevenson, D.R.; Kozak, E.T.; Davison, C.C.; Gascoyne, M.; Broadfoot, R.A.

    1996-06-01

    The hydrogeologic characteristics of the granitic Lac du Bonnet batholith in southeastern Manitoba have been studied since 1978, as part of AECL's program to assess the concept of disposing of Canada's nuclear fuel waste deep within plutonic rocks of the Canadian Shield (Davison et al. 1994a). These studies have included an extensive program of drilling, logging, testing, sampling and monitoring in 19 deep surface boreholes drilled at Grid areas located across the Lac du Bonnet batholith, at the Whiteshell Laboratory (WL), and in surface and underground boreholes at the Underground Research Laboratory (URL). Based on these investigations domains of low permeability, sparsely fractured rock (SFR) have been identified in the Lac du Bonnet batholith

  8. Sediment underthrusting within a continental magmatic arc: Coast Mountains batholith, British Columbia

    Science.gov (United States)

    Pearson, David M.; MacLeod, Douglas R.; Ducea, Mihai N.; Gehrels, George E.; Jonathan Patchett, P.

    2017-10-01

    Though continental magmatic arcs are factories for new continental crust, a significant proportion of continental arc magmas are recycled from supracrustal material. To evaluate the relative contributions of retroarc underthrusting and trench side partial sediment subduction for introducing supracrustal rocks to the middle and lower crust of continental magmatic arcs, we present results from the deeply exposed country rocks of the Coast Mountains batholith of western British Columbia. Prior work demonstrates that these rocks underwent widespread partial melting that contributed to the Coast Mountains batholith. We utilize U-Pb zircon geochronology, Sm-Nd thermochronology, and field-based studies to document the protoliths and early burial history of amphibolite and granulite-facies metasedimentary rocks in the Central Gneiss Complex. U-Pb detrital zircon data from the structurally highest sample localities yielded 190 Ma unimodal age peaks and suggest that retroarc rocks of the Stikine terrane constitute a substantial portion of the Central Gneiss Complex. These supracrustal rocks underwent thrust-related burial and metamorphism at >25 km depths prior to 80 Ma. These rocks may also be underlain at the deepest exposed structural levels by Upper Cretaceous metasedimentary rocks, which may have been emplaced as a result of trench side underplating or intraarc burial. These results further our understanding of the mechanisms of material transport within the continental lithosphere along Cordilleran subduction margins.

  9. Late cenozoic magmatism in the South Patagonian batholith: SHRIMP U-Pb zircon age evidence

    International Nuclear Information System (INIS)

    Fanning, C.M; Herve, F; Pankhurst, R.J; Thomson, S; Faundez, V

    2001-01-01

    The North Patagonian Batholith (NPB) has a zonal age pattern which includes a well defined belt of Miocene and Mio-Pliocene plutons in its central portion (Pankhurst et al., 1999) which are spatially, and probably genetically related to the Liquine-Ofqui Fault Zone. Previous geochronological studies in the Southern Patagonian Batholith (SPB), as summarized by Bruce et al. (1991), have yielded 9 late Cenozoic K-Ar or Ar-Ar ages out of a total of 116 age determinations. None of these young ages correspond to U-Pb determinations on zircons, and some of the young ages correspond to satellite plutons east of the SPB proper, such as the Torres del Paine intrusion. In this paper we present the first late Cenozoic SHRIMP U-Pb zircon ages in the area of the SPB. The morphology of the analysed zircon crystals is described and leads to some inferences on the methodology and on the geological interpretation of the obtained ages (au)

  10. Coexistence of galenas with different Pb isotopic composition in Los Pedroches batholith area (Spain)

    Science.gov (United States)

    García de Madinabeitia, S.; Santos Zalduegui, J. F.; Larrea, F. J.; Carracedo, M.; Gil Ibarguchi, J. I.

    2003-04-01

    The Los Pedroches batholith region (S Spain) includes three separated mining districts: Linares, La Carolina and Los Pedroches. The Pb isotopic composition of thirty-three galenas from this sector has been measured. On the basis of the Pb data two types of mineralization are established. A first type including: (i) the Linares and La Carolina districts where ore-bearing filons cut Hercynian granites or their hostrocks (SE of the batholith), and (ii) the so-called "peribatholithic" ore bodies represented by scarce mines in the host-rock of the batholith; all of them exhibit homogeneous Pb isotopic compositions of: 206Pb/204Pb = 18.236, 207Pb/204Pb = 15.615, 208Pb/204Pb = 38.347 and a model age of ca. 324 Ma. The second type is represented by a huge N120^oE hydrotermal vein (the El Zumajo vein) intrusive in granitoid bodies of the batholith; the Pb isotopic composition of the vein is: 206Pb/204Pb = 18.457, 207Pb/204Pb = 15.636, 208Pb/204Pb = 38.611 and a model age of ca. 201 Ma. Analysed K-feldspars from batholithic granodiorite and granites have Pb isotopic compositions similar to those reported previously from Hercynian granites of the area (1) and to the galenas of Linares, La Carolina and "peribatholithic" ores. The whole dataset reveals a Pb evolution curve with μ_2 = 9.8 and ω_2 = 38.3, close to the model curve for the "orogen" (2). This suggests for Linares, La Carolina and the "peribatholithic" mineralizations a Pb source related to that of the granites. The pre-Tremadoc metasedimentary rocks of the area, with Pb isotopic composition (3) very close to that of feldspars and galenas studied is proposed as a possible source of Pb for both the granites and associated mineralizations, although the Pb isotopic composition of El Zumajo calls for a different origin. The observed difference in Pb isotopic ratios of the studied galenas points to, at least, two ore-forming events: (i) one relating older mineralizations and granitoid intrusives, in agreement with

  11. Nevada Operations overview

    International Nuclear Information System (INIS)

    Church, B.W.

    1981-01-01

    A brief overview is given of weapon test site decontamination activities carried out by Nevada Operations Office. Tabulated data is given of event name, date, location, year of cleanup, and radioisotopes that were present, activity levels, and cost of cleanup

  12. Special Nevada report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-09-23

    This report is submitted to Congress by the Secretary of the Air Force, the Secretary of the Navy, and the Secretary of the Interior pursuant to Section 6 of the Military Lands Withdrawal Act of 1986. It contains an analysis and evaluation of the effects on public health and safety resulting from DOD and Department of Energy (DOE) military and defense-related uses on withdrawn public lands in the State of Nevada and in airspace overlying the State. This report describes the cumulative impacts of those activities on public and private property in Nevada and on plants, fish and wildlife, cultural, historic, scientific, recreational, wilderness and other resources of the public lands of Nevada. An analysis and evaluation of possible measures to mitigate the cumulative effects of the withdrawal of lands and the use of airspace in Nevada for defense-related purposes was conducted, and those considered practical are listed.

  13. Nevada state revenues analysis

    International Nuclear Information System (INIS)

    1988-06-01

    This report analyzes the major sources of revenue to the Nevada State General Fund for purposes of estimating impacts associated with the siting of a nuclear waste repository at Yucca Mountain in Nye County, Nevada. Each major revenue source is analyzed to identify relationships among the economic or demographic base, the revenue base, and the revenues generated. Trends and changes in the rates and/or base are highlighted. A model is developed for each revenue source to allow impact estimation

  14. EMPHASIS(TM)/Nevada Unstructured FEM Implementation Version 2.1.1.

    Energy Technology Data Exchange (ETDEWEB)

    Turner, C. David; Pointon, Timothy D.; Cartwright, Keith

    2014-08-01

    EMPHASIS TM /NEVADA is the SIERRA/NEVADA toolkit implementation of portions of the EMP HASIS TM code suite. The purpose of the toolkit i m- plementation is to facilitate coupling to other physics drivers such as radi a- tion transport as well as to better manage code design, implementation, co m- plexity, and important verification and validation processes. This document describes the theory and implementation of the unstructured finite - element method solver , associated algorithms, and selected verification and valid a- tion . Acknowledgement The author would like to recognize all of the ALEGRA team members for their gracious and willing support through this initial Nevada toolkit - implementation process. Although much of the knowledge needed was gleaned from document a- tion and code context, they were always willing to consult personally on some of the less obvious issues and enhancements necessary.

  15. Reading Comprehension Instruction Practices in Sierra Leone

    NARCIS (Netherlands)

    Hersbach, S.; Denessen, E.J.P.G.; Droop, W.

    2014-01-01

    Aim: In this study an attempt was made to give insight in the way reading comprehension is taught in Sierra Leone. Attention was paid to the didactical strategies and the materials used during reading comprehension instruction. Methodology: Primary school teachers in Sierra Leone (N=43) were

  16. Geological and geochemical characteristics of the Heerenveen and Mpuluzi batholiths south of the Barberton greenstone belt and preliminary thoughts on their petrogenesis

    International Nuclear Information System (INIS)

    Anhaeusser, C.R.; Robb, L.J.

    1982-01-01

    The Archaean granitic terrane south and south-west of the Barberton greenstone belt consists predominantly of an older suite of tonalitic and trondhjemitic gneisses into which have been emplaced two large multi-component granitoid bodies known as the Heerenveen and Mpuluzi batholiths. Although geochronologic and Sr-isotopic studies demonstrate that there is little distinction between the ages and initial ratios of the various phases associated with these batholiths, each body displays contrasting textural and geochemical characteristics. The oldest phase is represented by coarse porphyritic granitic rocks into which is intruded a medium-to-fine-grained homogeneous granodioritic phase. Both phases are components of a bimodal association that is, in turn, intruded by a third phase which includes medium-grained pink or grey granodiorite and adamellite dykes feeding a homogeneous sheet-like carapace over-lying the coarser porphyritic granites. A fourth phase, consisting predominantly of potassic migmatites and gneisses, occurs in the areas rimming the batholiths and represents the product of interaction between the batholith magmas and components of the pre-existing crust in the region. Geochemically, the Heerenveen batholith has trondhjemitic affinities whereas the Mpuluzi batholith consists predominantly of potassic granites. Together with the Nelspruit batholith north of the Barberton greenstone belt the three granitic bodies show a progression in actual values of K 2 O, Na 2 O, Rb, and Sr with the Nelspruit body having chemical characteristics intermediate between the two

  17. Sierra Pacific Power Company Alturas Transmission Line Project, Final Environmental Impact Report/Environmental Impact Statement. Volume 2: Comments and responses

    International Nuclear Information System (INIS)

    1995-11-01

    Sierra Pacific Power Company has proposed the construction and operation of a 345,000 volt overhead electric power transmission line from Alturas, California to Reno, Nevada. This Environmental Impact Report/Environmental Impact Statement will assess the potential environmental impacts of the proposed project and alternatives. This report contains public comments which were received on the Draft EIR/S. Significant issues may be identified through public and agency comments

  18. Sierra/SM theory manual.

    Energy Technology Data Exchange (ETDEWEB)

    Crane, Nathan Karl

    2013-07-01

    Presented in this document are the theoretical aspects of capabilities contained in the Sierra/SM code. This manuscript serves as an ideal starting point for understanding the theoretical foundations of the code. For a comprehensive study of these capabilities, the reader is encouraged to explore the many references to scientific articles and textbooks contained in this manual. It is important to point out that some capabilities are still in development and may not be presented in this document. Further updates to this manuscript will be made as these capabilites come closer to production level.

  19. Age and isotopic fingerprints of some plutonic rocks in the Wiborg rapakivi granite batholith with special reference to the dark wiborgite of the Ristisaari Island

    Directory of Open Access Journals (Sweden)

    Rämö, O.T.

    2014-12-01

    Full Text Available The mid-Proterozoic, locus classicus Wiborg rapakivi granite batholith of southeastern Finland and adjacent Russia comprises a varying, bimodal (silicic-basic sequence of plutonic, subvolcanic, and volcanic rocks. At the current level of erosion silicic rocks are dominant, the most prominent of which are wiborgites and dark wiborgites (that have been considered to mark the main build-up stage of the batholith and pyterlites. New observations and optical microscopy data from the dark wiborgite-dominated Ristisaari Island in the southern, off-shore part of the Wiborg batholith show that dark plagioclase megacrysts in dark wiborgite are calcic xenocrysts. They were probably incorporated into wiborgite magma from consanguineous massiftype anorthosite magmas in the course of the evolution of the bimodal magmatic system. Our new ID-TIMS U-Pb zircon age of the Ristisaari Island dark wiborgite, 1627±3 Ma, is the youngest isotopic age so far determined for the plutonic rocks of the Wiborg batholith. This, combined with preexisting U-Pb zircon data, implies a minimum duration of 12 m.y. (1642–1630 Ma for the emplacement of the plutonic rocks of the batholith. Combined with data on highlevel dike rocks, a window of at least 20 m.y. (1642–1622 Ma is implied. Furthermore, as the batholith grew, the overall locus of magmatism may have shifted southwards. New whole-rock Nd isotope data on the dark wiborgite of the Ristisaari Island and three further granites of the batholith, as well as Nd (whole-rock and Sr (whole-rock, plagioclase isotope data on a spectrolite massif-type anorthosite from the east-central part of the batholith, are also presented. These data suggest that the lithosphere across the Wiborg batholith area in the southeastern part of the Svecofennian orogen may vary slightly in overall mantle separation age.

  20. Status and understanding of groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units, 2006-2007--California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units was investigated as part of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The three study units are located in the Sierra Nevada region of California in parts of Nevada, Placer, El Dorado, Madera, Tulare, and Kern Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board, in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The project was designed to provide statistically robust assessments of untreated groundwater quality within the primary aquifer systems used for drinking water. The primary aquifer systems (hereinafter, primary aquifers) for each study unit are defined by the depth of the screened or open intervals of the wells listed in the California Department of Public Health (CDPH) database of wells used for municipal and community drinking-water supply. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifers; shallower groundwater may be more vulnerable to contamination from the surface. The assessments for the Tahoe-Martis, Central Sierra, and Southern Sierra study units were based on water-quality and ancillary data collected by the USGS from 132 wells in the three study units during 2006 and 2007 and water-quality data reported in the CDPH database. Two types of assessments were made: (1) status, assessment of the current quality of the groundwater resource, and (2) understanding, identification of the natural and human factors affecting groundwater quality. The assessments characterize untreated groundwater quality, not the quality of treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentrations divided by benchmark concentrations) were used for evaluating groundwater quality for those

  1. Petrogenesis of the postcollisional Middle Devonian monzonitic to granitic magmatism of the Sierra de San Luis, Argentina

    Science.gov (United States)

    López de Luchi, Mónica G.; Siegesmund, Siegfried; Wemmer, Klaus; Nolte, Nicole

    2017-09-01

    Middle Devonian granitoids intruded the Eastern Sierras Pampeanas basement ca. 600 km east of the inferred proto-Pacific margin of Gondwana along which a ca. 390 Ma collisional event developed. In the Sierra de San Luis, voluminous Middle Devonian (393-382 Ma) batholiths are composed of I- to A-type hybrid Monzonite and Granite suites. Shoshonite and subordinated high-K series, stocks, synplutonic dikes and enclaves make up the Monzonite Suite; rocks are metaluminous alkali-calcic magnesian porphyritic or equigranular monzonite, quartz monzonite, monzodiorite and scarce monzogabbro. High-K and subordinated shoshonite series metaluminous to mildly peraluminous magnesian alkali-calcic to calc-alkalic porphyritic or equigranular quartz monzonite, granodiorite, monzogranite and equigranular leucomonzogranites make up the Granite Suite plutons and batholiths. Only a small group of highly evolved granites are ferroan. SiO2 (46-62%), Cr, Ni, V, Sc, LILE, LREE, Th, Zr and variable, Sr/Y, (La/Yb)N and (Tb/Yb)N, smooth Eu/Eu*, moderate Na2O (ca 3.5), and troughs at Nb and Ta for Monzonite Suite rocks suggest an subduction-related enriched lithospheric mantle source. Sm-Nd data (TDM 0.98-1.08 Ga, εNd(380 Ma) 0.66-1.47) and 87Sr/86Sri (0.703520-0.704203) are compatible with an enriched mantle source. The metaluminous porphyritic quartz monzonite-monzogranite and the mildly peraluminous equigranular biotite monzogranites of the Granite Suite are characterized by relatively moderate Al2O3, CaO, and 87Sr/86Sri, high LILE, Cr, variable Sr/Y, (La/Yb)N and Eu/Eu* and low Rb/Sr ( 1.5, ASI 1.05-1.18, and Ga/Al 2.6-3.9, εNd(380 Ma) - 3.74 to - 3.95 and (87Sr/86Sr)i 0.710743-0.712955 which would point to metasedimentary or felsic igneous crustal sources. Nevertheless their TDM 1.36-1.38 Ga is considerably younger than the mean 1.8-1.6 Ga Eastern Sierras Pampeanas crustal residence age and less radiogenic. Middle Devonian magmatism would record an episode of crustal growth by enriched

  2. Petrology and geochronology of the Cacapava do Sul batholith, state of Rio Grande do Sul, Brazil

    International Nuclear Information System (INIS)

    Sartori, P.L.P.; Kawashita, K.

    1985-01-01

    The batholith of Cacapava do Sul, Brazil, is composed of granitic rocks represented by leucogranites, syenogranites, monzogranites and granodiorites, arranged in a complex way. These rocks represent a calcalkaline suite of compressional tectonic setting. The general characteristics described with respect to it's petrography, chemical composition and geological setting show similarities with mesozone plutons. The pluton intruded the metamorphic rocks of the Vacacai Formation and the type of emplacement mechanism was forceful. According to the Rb-Sr total rock isochron age determinations, its consolidation took place throughout the Cambrian period. This result agrees with previous K-Ar age determinations. The intrusion occurred at the end of the Brasiliano orogenic cycle, when the metamorphic and folding phenomena had already ceased and the morphogenesis was in progress, since the temperature for radiometric argon retention was reached rapidly. (D.J.M.) [pt

  3. Dating fractures and fracture movement in the Lac du Bonnet Batholith

    International Nuclear Information System (INIS)

    Gascoyne, M.; Brown, A.; Ejeckam, R.B.; Everitt, R.A.

    1997-04-01

    This report examines and summarizes all work that has been done from 1980 to the present in determining the age of rock crystallization, fracture initiation, fracture reactivation and rates of fracture movement in the Lac du Bonnet Batholith to provide information for Atomic Energy of Canada Limited's (AECL) Canadian Nuclear Fuel Waste Management Program. Geological and petrographical indicators of relative age (e.g. cross-cutting relationships, sequences of fracture infilling minerals, P-T characteristics of primary and secondary minerals) are calibrated with radiometric age determinations on minerals and whole rock samples, using 87 Rb- 87 Sr, 40 K- 39 Ar, 40 Ar- 39 Ar and fission track methods. Most fractures and fracture zones inclined at low angles are found to be ancient features, first formed in the Early Proterozoic under conditions of deuteric alteration. Following some movement on fractures in the Late Proterozoic and Early Paleozoic, reactivation of fractures during the Pleistocene is established from uranium-series dating methods and use of stable isotopic contents of fracture infilling minerals (mainly calcite). Some indication of movement on fracture zones during the Pleistocene is given by electron spin resonance dating techniques on fault gouge. The slow rate of propagation of fractures is indicated by mineral infillings, their P-T characteristics and U-series calcite ages in a fracture in sparsely fractured rock, accessible from AECL's Underground Research Laboratory. These results collectively indicate that deep fractures observed in the batholith are ancient features and the fracturing and jointing in the upper 200 m is relatively recent (< 1 Ma) and largely a result of stress release. (author)

  4. Simulating the Thermal History of the Unsaturated Zone at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    B.D. Marshal; J.F. Whelan

    2001-01-01

    Heat transfer within Earth's upper crust is primarily by conduction, and conductive thermal models adequately explain the cooling history of deep, batholith-scale intrusions and surrounding wall rocks, as confirmed by numerous thermochronometric studies. However, caldera magmatic systems require consideration of the small and localized component of hydrothermal convection and numerical models to simulate additional boundary conditions, irregular magma chamber shapes, and complex intrusive histories. At Yucca Mountain, Nevada, the site of a potential high-level nuclear waste repository, simulating the detailed thermal history at any location in the unsaturated zone requires knowledge of the shape of the magma chamber and its proximity to Yucca Mountain (the southern margin of the Timber Mountain caldera complex is approximately 8 km north of the potential repository site), the temporal and spatial extent of hydrothermal convection, the erosional history of the area, and past levels of the water table

  5. Legacy K/Ar and 40Ar/39Ar geochronologic data from the Alaska-Aleutian Range batholith of south-central Alaska

    Science.gov (United States)

    Koeneman, Lisa L.; Wilson, Frederic H.

    2018-04-06

    Sample descriptions and analytical data for more than 200 K/Ar and 40Ar/39Ar analyses from rocks of the Alaska-Aleutian Range batholith of south-central Alaska are reported here. Samples were collected over a period of 20 years by Bruce R. Reed and Marvin A. Lanphere (both U.S. Geological Survey) as part of their studies of the batholith.

  6. Quelques observations sur la dynamique géomorphologique actuelle et passée de deux régions colombiennes: le haut bassin du rio Lebrija et le piemont nord-occidental de la Sierra Nevada de Santa Marta

    Directory of Open Access Journals (Sweden)

    1972-01-01

    Full Text Available Plus de 80000 Chinois furent 'importés de force' au Pérou entre 1854 et 1874, année où le Traité de Tien Tsin mit fin à ce trafic. Le Pérou de cette seconde moitié du XIXe souffrait d'un manque de main-d'oeuvre aigu, situation aggravée par la libération des esclaves noirs d'une part et d'autre part par l'essor prit par les haciendas sucrières, la construction des premières lignes de chemin de fer et l'extraction du guano. Entre 1860 et 1870 par exemple arrivèrent au seul port de Callao plus de 38000 'coolies'. En 1876, dans la province de Chancay à Aucallama étaient employés 1225 'asiáticos' soit plus de 66% de la population locale. A la fin du siècle, beaucoup étaient morts, certains avaient réussi à retourner en Chine, et d'autres s'étaient définitivement installés, rejoints par une seconde vague de Chinois commerçants attirés par l'essor du Pérou. La plupart des Chinois s'établirent sur la côte où ils étaient arrivés et dans des centres urbains. Même parmi ceux qui travaillèrent dans la construction des chemins de fer, très peu s'installèrent définitivement dans les régions minières d'altitude. A Acos, petite communauté (300 à 400 habitants de la vallée du Chancay établie dans un fond de vallée chaude ou 'quebrada de yunga', on a retrouvé la présence d'une micro-colonie de Chinois. Dans quelles circonstances aboutirent-ils dans ce village de 'sierra' (1 550 m? Comment s'y intégrèrent-ils et quel fut leur rôle économique sont les questions que nous nous poserons dans cet article, puis dans un suivant traitant spécifiquement de leur rôle dans l'essor du village. Notons un dernier point: le village d'Acos à l'arrivée des Chinois était dominé par un groupe de familles dites 'légitimes' qui détenaient surtout un pouvoir fondé sur la propriété foncière. Les Chinois, en contribuant à développer l'économie de Fue entre 1854 y 1874, año en que el Tratado de Tien Tsin puso fin a ese tr

  7. Nevada Isostatic Gravity Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 2 kilometer Isostatic anomaly grid for the state of Nevada. Number of columns is 269 and number of rows is 394. The order of the data is from the lower left to the...

  8. Running Parallel Discrete Event Simulators on Sierra

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jefferson, D. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-12-03

    In this proposal we consider porting the ROSS/Charm++ simulator and the discrete event models that run under its control so that they run on the Sierra architecture and make efficient use of the Volta GPUs.

  9. Aspen Delineation - Sierra State Parks [ds380

    Data.gov (United States)

    California Natural Resource Agency — The database represents delineations of aspen stands associated with stand assessment data (SIERRA_SP_PTS) collected in aspen stands on lands administered by the...

  10. Field characteristics, petrography, and geochronology of the Hohonu Batholith and the adjacent Granite Hill Complex, North Westland, New Zealand

    International Nuclear Information System (INIS)

    Waight, T.E.; Weaver, S.D.; Ireland, T.R.; Maas, R.; Muir, R.J.; Shelley, D.

    1997-01-01

    Detailed geological mapping, petrography, geochemistry and geochronological studies in the Hohonu Batholith, North Westland, have identified 10 granitoid plutons emplaced during three intrusive episodes. The earliest episode is represented by a single dated Paleozoic pluton, Summit Granite (new) (381.2 ± 7.3 Ma), which is correlated with a discrete pulse of Mid-Late Devonian plutonism recognised in the Karamea Batholith. The undated Mount Graham Granite (new) is also likely to be Paleozoic, based on chemical and petrographic characteristics. The bulk of the batholith (seven plutons) was emplaced in the mid Cretaceous (114-109 Ma) and comprises two related, yet distinct, geochemical suites, which correlate with the previously defined Rahu Suite. The plutons identified are (from north to south): Pah Point Granite; Jays Creek Granodiorite (new); Uncle Bay Tonalite; Te Kinga Monzogranite; Deutgam Granodiorite; Turiwhate Granodiorite (new); and Arahura Granite (new). Mid-Cretaceous plutonism in the Western Province is considered to be the result of crustal thinning and extension following overthickening during collision of the Early Cretaceous Median Tectonic Zone volcanic arc. Late Cretaceous alkaline activity is represented by the emplacement of the A-type French Creek Granite at 1.7 ± 1.8 Ma, contemporaneous with intrusion of a major swarm of doleritic-lamprophyric dikes - the Hohonu Dike Swarm. These events correlate with the first appearance of oceanic crust in the Tasman Sea. The Granite Hill Complex is a suite of amphibolite facies gneisses occurring as an uplifted wedge between the Alpine Fault nd the Hohonu Batholith. These gneisses are considered to represent an extension of the Fraser Complex to the south. A detailed understanding of their geological affinities and history is yet to be established. (author). 66 refs., 7 figs., 3 tabs

  11. Thermal history of the Kunlun batholith, N. Tibet, and implications for uplift of the Tibetan plateau

    International Nuclear Information System (INIS)

    Lewis, C.L.E.

    1990-01-01

    Preliminary Rb-Sr and 40 Ar/ 39 Ar biotite ages combined with zircon and apatite fission track dates from the Hunlun batholith in northern Tibet allow for comparison with the previously established uplift history of southern Tibet, and inferences to be made about uplift of the plateau as a whole. Across a major divide at the Golmud Fault, apatite ages decrease from 100 Ma in the north to 20 Ma in the south. This is believed to be as a result of a thrusting event at 120 Ma which uplifted the Northern block and overthrust the Southern block to the south. Subsequent to this event, surface approach rates of less than 70 m Ma -1 from biotite closure at 120 Ma to apatite cooling at 20 Ma in the Southern block, indicate a long uninterrupted period of thermal equilibration in an essentially static continental block. Mean confined track lengths of 12.5-13.5 μm in apatites suggest that samples exposed at the surface today resided in the fission track partial annealing zone prior to the onset of uplift which must have occurred subsequent to 20 Ma. This indicates that at least 3-4 km have been uplifted since this time and that the onset of this phase could have been as recent as 8 Ma. (author)

  12. Emplacement and geochemical evolution of eocene plutonic rocks in the Colville batholith

    International Nuclear Information System (INIS)

    Holder, R.W.

    1986-01-01

    Eocene plutonic rocks in the Colville batholith are divided on the basis of field evidence and chemical composition into, in order of decreasing age, (1) several calc-alkalic biotite-hornblende monzodiorite to granodiorite intrusions referred to as the Devils Elbow suite, and (2) compositionally variable calc-alkalic to alkali-calcic intrusions referred to as the Herron Creek suite. These Eocene suites are distinct from older, more voluminous, leucocratic granite and granodiorite intrusions, designated the Keller Butte suite, which are calcic and characteristically lack hornblende. Results of qualitative and computer modeling of major element variation and quantitative models of trace element variation in the chemically coherent Bridge Creek intrusions, a member of the Herron Creek suite, are compatible with fractionation of plagioclase feldspar + hornblende + biotite + magnetite + apatite from a parent magma of andesitic composition to account for the observed variation. Strongly curved variation trends preclude mixing as the primary mechanism for the observed variation. It is suggested that parallel variation trends in the other Eocene intrusions are also the result of crystal fractionation. Lateral chemical variations including a decrease in silica saturation suggest the chemical characteristics of these rocks reflect those of parental magmas derived from the mantle, with an unknown amount of crustal contribution. Rotated and angular xenoliths, discordant contacts, and temporal and spatial proximity to graben structures indicate that the Eocene plutons were passively implaced into the upper crust along graben-bounding faults during graben formation, the earlier stages of which appear to have been contemporaneous with regional mylonitic deformation

  13. Control of Precambrian basement deformation zones on emplacement of the Laramide Boulder batholith and Butte mining district, Montana, United States

    Science.gov (United States)

    Berger, Byron R.; Hildenbrand, Thomas G.; O'Neill, J. Michael

    2011-01-01

    What are the roles of deep Precambrian basement deformation zones in the localization of subsequent shallow-crustal deformation zones and magmas? The Paleoproterozoic Great Falls tectonic zone and its included Boulder batholith (Montana, United States) provide an opportunity to examine the importance of inherited deformation fabrics in batholith emplacement and the localization of magmatic-hydrothermal mineral deposits. Northeast-trending deformation fabrics predominate in the Great Falls tectonic zone, which formed during the suturing of Paleoproterozoic and Archean cratonic masses approximately 1,800 mega-annum (Ma). Subsequent Mesoproterozoic to Neoproterozoic deformation fabrics trend northwest. Following Paleozoic through Early Cretaceous sedimentation, a Late Cretaceous fold-and-thrust belt with associated strike-slip faulting developed across the region, wherein some Proterozoic faults localized thrust faulting, while others were reactivated as strike-slip faults. The 81- to 76-Ma Boulder batholith was emplaced along the reactivated central Paleoproterozoic suture in the Great Falls tectonic zone. Early-stage Boulder batholith plutons were emplaced concurrent with east-directed thrust faulting and localized primarily by northwest-trending strike-slip and related faults. The late-stage Butte Quartz Monzonite pluton was localized in a northeast-trending pull-apart structure that formed behind the active thrust front and is axially symmetric across the underlying northeast-striking Paleoproterozoic fault zone, interpreted as a crustal suture. The modeling of potential-field geophysical data indicates that pull-apart?stage magmas fed into the structure through two funnel-shaped zones beneath the batholith. Renewed magmatic activity in the southern feeder from 66 to 64 Ma led to the formation of two small porphyry-style copper-molybdenum deposits and ensuing world-class polymetallic copper- and silver-bearing veins in the Butte mining district. Vein orientations

  14. Petrography and Geochemistry of the Zamora Batholith in the south of the sub-Andean zone (Ecuador)

    Science.gov (United States)

    Villares, F. M.

    2013-05-01

    The Zamora Batholith is an intrusive complex that is located in the extreme south-east of Ecuador. It has dimensions of 200 x 50 km approximately. It is mainly located in the Zamora Chinchipe province from which it takes its name. This study consisted in the petrographic and geochemical characterization of the Zamora Batholith in the area covered by 1: 50,000 geological maps of Centro Shaime, Guayzimi, Paquisha, Los Encuentros and El Pangui. Fieldwork was done by the "Proyecto Mapeo Geológico escala 1:50.000 (zonas prospectivas mineras)" of the Instituto Nacional de Investigación Geológico, Minero, Metalúrgico of Ecuador. This research was performed with 59 thin sections and 10 whole - rock chemical analysis done in the C.I.C of the Granada University. The Zamora Batholith intrudes Triassic to Jurassic volcanic rocks. It is overlaid by sandstones of the Hollin Formation of the Upper Aptian age and shale and limestone from the Napo Formation. Post-cretaceous deposits of ash and lava flows of andesitic to rhyolitic compositions cover the batholith. The petrography of the Zamora Batholith ranges from tonalite to monzogranite with the same qualitative mineralogy. The rocks are composed by different proportions of plagioclase, amphibole, feldspar K, quartz, biotite, opaque, pyroxene and epidote, as accessory minerals has zircon, sphene and apatite. To the south of the Conguime and Guayzimi towns, the dominant petrography is medium to coarse grained amphibole granodiorite with tonalitic and monzogranitic subordinates. To the north monzogranites are dominant rocks and subordinate granodiorites. To the East of Santa Elena the sienogranites are associated with El Hito porphyritic granite that intrudes to Zamora Batholith. Frequently the batholith has propylitic alteration; which produces a primary association of chlorite, epidote, calcite and pyrite. The granitoids have dioritic to granitic compositions (60.09 to 73.6 wt.% SiO2) and are I - type, medium to high-K calc

  15. Evidence and theory for the prediction of tectonic activity in the Basin and Range Province of Nevada and Utah for the next one million years

    International Nuclear Information System (INIS)

    Lovejoy, E.M.P.

    1979-01-01

    Major conclusions of the report are: Important seismic activity in the next one million years will be restricted to the Intermountain Seismic Belt. Minor seismic activity in the same period will be restricted to the Nevada Seismic Belt, Sierra Nevada front, and Reno-Yellowstone lineament. There will be seismic inactivity in the same period in the rest of the Basin and Range Province except locally along high mountain frontal fault zones. In these zones, isostatic unloading will produce slow, secular, mild seismic activity for many millions of years to come

  16. Sierra/SolidMechanics 4.46 Example Problems Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Plews, Julia A.; Crane, Nathan K; de Frias, Gabriel Jose; Le, San; Littlewood, David John; Merewether, Mark Thomas; Mosby, Matthew David; Pierson, Kendall H.; Porter, Vicki L.; Shelton, Timothy; Thomas, Jesse David; Tupek, Michael R.; Veilleux, Michael

    2018-03-01

    Presented in this document are tests that exist in the Sierra/SolidMechanics example problem suite, which is a subset of the Sierra/SM regression and performance test suite. These examples showcase common and advanced code capabilities. A wide variety of other regression and verification tests exist in the Sierra/SM test suite that are not included in this manual.

  17. Sierra toolkit computational mesh conceptual model

    International Nuclear Information System (INIS)

    Baur, David G.; Edwards, Harold Carter; Cochran, William K.; Williams, Alan B.; Sjaardema, Gregory D.

    2010-01-01

    The Sierra Toolkit computational mesh is a software library intended to support massively parallel multi-physics computations on dynamically changing unstructured meshes. This domain of intended use is inherently complex due to distributed memory parallelism, parallel scalability, heterogeneity of physics, heterogeneous discretization of an unstructured mesh, and runtime adaptation of the mesh. Management of this inherent complexity begins with a conceptual analysis and modeling of this domain of intended use; i.e., development of a domain model. The Sierra Toolkit computational mesh software library is designed and implemented based upon this domain model. Software developers using, maintaining, or extending the Sierra Toolkit computational mesh library must be familiar with the concepts/domain model presented in this report.

  18. Lithogeochemistry of the main unities of Pelotas batholith from Rio Grande do Sul State

    International Nuclear Information System (INIS)

    Figueiredo, M.C.H. de; Cesar, A.R.S.; Kronberg, B.I.

    1990-01-01

    The Pelotas batholith is composed predominantly of a Cambrian multi-intrusive granitic complex (Dom Feliciano Granitic Suite) associated to rhyolitic dike swarms and small basic plutons. The Piratini Gneisses (Late Riphean -Vendian) correspond to calcalkaline dioritic-tonalitic-granodioritic orthogneisses with chemical features of pre-collisional granitoids related to oceanic crust subduction (B-subduction) under an active continental margin. The Pinheiro Machado Granitoids (Vendian) are alkali-calcic granodiorite-monzogranites with Caledonian-type characteristics, but appear to also correspond to pre-collisional granitoids as a latter and more mature phase in the evolution of the magmatic arc. The Dom Feliciano Granitic Suite (Cambrian) is subdivided into porphyritic and equigranular facies, with predominance of monzogranites and syenogranites, respectively, with alkali-calcic late-orogenic characteristics. While the Rb/Sr isotopic data is consistent with the proposed evolution, the Nd model ages range from 2.0 - 1.2 Ga. This may reflect episodes of Sm/Nd fractionation within a lithospheric mantle instead of the accretion age of the granitoids. These apparent ages, which are also obtained in Parana and Karroo continental basalts, probably indicate coupled evolution of the continental crust and lithospheric mantle. In the suggested model, the Piratini Gneisses were orginated by differentiation of basic magmas formed by partial melting of lithospheric mantle, induced by dehydration of subducted oceanic crust, while the more mature arc granitoids had increasing crustal contamination or mingling-mixing with crustal melts and finally, in the late-and post-orogenic stages, partial melting of continental crust predominates. (author)

  19. The Special Court for Sierra Leone

    DEFF Research Database (Denmark)

    Damgaard, Ciara Therése

    2004-01-01

    The focus of this article is the Special Court for Sierra Leone and the extent to which it can be said that the Special Court has already challenged, or will, in the future, challenge the tradition of impunity for gender-based crimes. In this regard, an analysis is undertaken of the Special Court......'s Statute, Rules of Procedure and Evidence and practice to date, in order to determine its treatment of gender-based crimes and whether it can be said that the Special Court for Sierra Leone challenges the tradition of impunity for gender-based crimes. Udgivelsesdato: december 2004...

  20. Geologic map of the Bodie Hills, California and Nevada

    Science.gov (United States)

    John, David A.; du Bray, Edward A.; Box, Stephen E.; Vikre, Peter G.; Rytuba, James J.; Fleck, Robert J.; Moring, Barry C.

    2015-01-01

    The Bodie Hills covers about 1,200 km2 straddling the California-Nevada state boundary just north of Mono Lake in the western part of the Basin and Range Province, about 20 km east of the central Sierra Nevada. The area is mostly underlain by the partly overlapping, middle to late Miocene Bodie Hills volcanic field and Pliocene to late Pleistocene Aurora volcanic field (John and others, 2012). Upper Miocene to Pliocene sedimentary deposits, mostly basin-filling sediments, gravel deposits, and fanglomerates, lap onto the west, north, and east sides of the Bodie Hills, where they cover older Miocene volcanic rocks. Quaternary surficial deposits, including extensive colluvial, fluvial, glacial, and lacustrine deposits, locally cover all older rocks. Miocene and younger rocks are tilted ≤30° in variable directions. These rocks are cut by several sets of high-angle faults that exhibit a temporal change from conjugate northeast-striking left-lateral and north-striking right-lateral oblique-slip faults in rocks older than about 9 Ma to north- and northwest-striking dip-slip faults in late Miocene rocks. The youngest faults are north-striking normal and northeast-striking left-lateral oblique-slip faults that cut Pliocene-Pleistocene rocks. Numerous hydrothermal systems were active during Miocene magmatism and formed extensive zones of hydrothermally altered rocks and several large mineral deposits, including gold- and silver-rich veins in the Bodie and Aurora mining districts (Vikre and others, in press).

  1. Thermochronology of Cretaceous batholithic rocks in the northern Peninsular Ranges batholith, southern California: Implications for the Late Cretaceous tectonic evolution of southern California

    Science.gov (United States)

    Miggins, Daniel P.; Premo, Wayne R.; Snee, Lawrence W; Yeoman, Ross; Naeaer, Nancy D.; Naeser, Charles W.; Morton, Douglas M.

    2014-01-01

    The thermochronology for several suites of Mesozoic metamorphic and plutonic rocks collected throughout the northern Peninsular Ranges batholith (PRB) was studied as part of a collaborative isotopic study to further our understanding of the magmatic and tectonic history of southern California. These sample suites include: a traverse through the plutonic rocks across the northern PRB (N = 29), a traverse across a central structural and metamorphic transition zone of mainly metasedimentary rocks at Searl ridge (N = 20), plutonic samples from several drill cores (N = 7) and surface samples (N = 2) from the Los Angeles Basin, a traverse across the Eastern Peninsular Ranges mylonite zone (N = 6), and a suite of plutonic samples collected across the northern PRB (N = 13) from which only biotite 40Ar/39Ar ages were obtained. These geochronologic data help to characterize five major petrologic, geochemical, and isotopic zonations of the PRB (western zone, WZ; western transition zone, WTZ; eastern transition zone, ETZ; eastern zone, EZ; and upper-plate zone, UPZ).Apparent cooling rates were calculated using U-Pb zircon (zr) and titanite (sphene) ages; 40Ar/39Ar ages from hornblende (hbl), biotite (bi), and K-feldspar (Kf); and apatite fission-track (AFT) ages from the same samples. The apparent cooling rates across the northern PRB vary from relatively rapid in the west (zr-hbl ~210 °C/m.y.; zr-bio ~160 °C/m.y.; zr-Kf ~80 °C/m.y.) to less rapid in the central (zr-hb ~280 °C/m.y.; zr-bio ~90 °C/m.y.; zr-Kf ~60 °C/m.y.) and eastern (zr-hbl ~185 °C/m.y.; zr-bio ~180 °C/m.y.; zr-Kf ~60 °C/m.y.) zones. An exception in the eastern zone, the massive San Jacinto pluton, appears to have cooled very rapidly (zr-bio ~385 °C/m.y.). Apparent cooling rates for the UPZ samples are consistently slower in comparison (~25–45 °C/m.y.), regardless of which geochronometers are used.Notable characteristics of the various ages from different dating methods include: (1) Zircon

  2. Active deformation in the northern Sierra de Valle Fértil, Sierras Pampeanas, Argentina

    Science.gov (United States)

    Ortiz, Gustavo; Alvarado, Patricia; Fosdick, Julie C.; Perucca, Laura; Saez, Mauro; Venerdini, Agostina

    2015-12-01

    The Western Sierras Pampeanas region in the San Juan Province is characterized by thick-skinned deformation with approximately N-S trending ranges of average heights of 2500 m and a high frequency occurrence of seismic activity. Its location to the east of the mainly thin-skinned tectonics of the Argentine Precordillera fold-and-thrust belt suggests that at 30°S, deformation is concentrated in a narrow zone involving these two morphostructural units. In this paper, we present new apatite (U-Th)/He results (AHe) across the northern part of the Sierra de Valle Fértil (around 30°S) and analyze them in a framework of thermochronologic available datasets. We found Pliocene AHe results for Carboniferous and Triassic strata in the northern Sierra de Valle Fértil consistent with the hypothesis of recent cooling and inferred erosional denudation concentrated along the northern end of this mountain range. Our analysis shows that this northern region may have evolved under different conditions than the central part of the Sierra de Valle Fértil. Previous studies have observed AHe ages consistent with Permian through Cretaceous cooling, indicating the middle part of the Sierra de Valle Fértil remained near surface before the Pampean slab subduction flattening process. Those studies also obtained ˜5 My cooling ages in the southern part of the Sierra de Valle Fértil, which are similar to our results in the northern end of the range. Taken together, these results suggest a pattern of young deformation in the northern and southern low elevation ends of the Sierra de Valle Fértil consistent with regions of high seismic activity, and Quaternary active faulting along the western-bounding thrust fault of the Sierra de Valle Fértil.

  3. Multiple Emplacement and Exhumation History of the Late Mesozoic Dayunshan-Mufushan Batholith in Southeast China and Its Tectonic Significance: 1. Structural Analysis and Geochronological Constraints

    Science.gov (United States)

    Ji, Wenbin; Faure, Michel; Lin, Wei; Chen, Yan; Chu, Yang; Xue, Zhenhua

    2018-01-01

    The South China Block (SCB) experienced a polyphase reworking by the Phanerozoic tectonothermal events. To better understand its Late Mesozoic tectonics, an integrated multidisciplinary investigation has been conducted on the Dayunshan-Mufushan composite batholith in the north-central SCB. This batholith consists of two major intrusions that recorded distinct emplacement features. According to our structural analysis, two deformation events in relation to batholith emplacement and subsequent exhumation are identified. The early one (D1) was observed mostly at the southern border of the batholith, characterized by a top-to-the-SW ductile shearing in the early-stage intrusion and along its contact zone. This deformation, chiefly associated with the pluton emplacement at ca. 150 Ma, was probably assisted by farfield compression from the northern Yangtze foreland belt. The second but main event (D2) involved two phases: (1) ductile shearing (D2a) prominently expressed along the Dayunshan detachment fault at the western border of the batholith where the syntectonic late-stage intrusion and minor metasedimentary basement in the footwall suffered mylonitization with top-to-the-NW kinematics; and (2) subsequent brittle faulting (D2b) further exhumed the entire batholith that behaved as rift shoulder with half-graben basins developed on its both sides. Geochronological constraints show that the crustal ductile extension occurred during 132-95 Ma. Such a Cretaceous NW-SE extensional tectonic regime, as indicated by the D2 event, has been recognized in a vast area of East Asia. This tectonism was responsible not only for the destruction of the North China craton but also for the formation of the so-called "southeast China basin and range tectonics."

  4. Explaining Violence in Sierra Leone's Civil War

    African Journals Online (AJOL)

    Explaining the violence of civil war is never a simple task for the scholar. In the case of the Sierra Leone, paradoxically, the task has in some ways been rendered more difficult by the sheer variety of compelling scholarship on the question. This paper seeks to identify the most useful of the explanations offered thus far, and ...

  5. Rebellion and Agrarian Tensions in Sierra Leone

    NARCIS (Netherlands)

    Peters, K.; Richards, P.

    2011-01-01

    This paper assesses the extent to which customary governance in Sierra Leone can be held responsible for an increasingly unstable two-class agrarian society. A case is made for regarding the civil war (1991–2002) as being an eruption of long-term, entrenched agrarian tensions exacerbated by chiefly

  6. Sierra Leone Journal of Biomedical Research: Submissions

    African Journals Online (AJOL)

    AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING ... Sierra Leone Journal of Biomedical Research (SLJBR) publishes papers in all ... An original article should give sufficient detail of experimental procedures for .... For references cited in a paper which has been accepted for publication but not ...

  7. Rice genetic resources in postwar Sierra Leone

    NARCIS (Netherlands)

    Chakanda, R.T.M.

    2009-01-01

    This research presents the effect of the 10-year long civil war in Sierra Leone on rice genetic resources, using farmers and their seed systems in three selected districts as reference points. The war disrupted all forms of production and development in the country and like other sectors of the

  8. Sierra Leone Journal of Biomedical Research

    African Journals Online (AJOL)

    The Sierra Leone Journal of Biomedical Research publishes papers in all fields of Medicine and Allied Health Sciences including Basic Medical Sciences, Clinical Sciences, Dental Sciences, Behavioural Sciences, Biomedical Engineering, Molecular Biology, Pharmaceutical Sciences, Biotechnology in relation to Medicine, ...

  9. Nevada Transportation Options Study

    International Nuclear Information System (INIS)

    P. GEHNER; E.M. WEAVER; L. FOSSUM

    2006-01-01

    This study performs a cost and schedule analysis of three Nevada Transportation options that support waste receipt at the repository. Based on the U.S. Department of Energy preference for rail transportation in Nevada (given in the Final Environmental Impact Statement), it has been assumed that a branch rail line would be constructed to support waste receipt at the repository. However, due to potential funding constraints, it is uncertain when rail will be available. The three Nevada Transportation options have been developed to meet a varying degree of requirements for transportation and to provide cost variations used in meeting the funding constraints given in the Technical Direction Letter guidelines for this study. The options include combinations of legal-weight truck, heavy-haul truck, and rail. Option 1 uses a branch rail line that would support initial waste receipt at the repository in 2010. Rail transportation would be the primary mode, supplemented by legal weight trucks. This option provides the highest level of confidence in cost and schedule, lowest public visibility, greatest public acceptability, lowest public dose, and is the recommended option for support of waste receipt. The completion of rail by 2010 will require spending approximately $800 million prior to 2010. Option 2 uses a phased rail approach to address a constrained funding scenario. To meet funding constraints, Option 2 uses a phased approach to delay high cost activities (final design and construction) until after initial waste receipt in 2010. By doing this, approximately 95 percent of the cost associated with completion of a branch rail line is deferred until after 2010. To support waste receipt until a branch rail line is constructed in Nevada, additional legal-weight truck shipments and heavy-haul truck shipments (on a limited basis for naval spent nuclear fuel) would be used to meet the same initial waste receipt rates as in Option 1. Use of heavy-haul shipments in the absence

  10. Nevada Test Site, Nye County, Nevada. Final environmental impact statement

    International Nuclear Information System (INIS)

    1977-09-01

    This environmental statement for the Nevada Test Site (NTS) considers underground nuclear detonations with yields of one megaton or less, along with the preparations necessary for such detonations. The testing activities considered also include other continuing and intermittent activities, both nuclear and nonnuclear, which can best be conducted in the remote and controlled area of the Nevada Test Site. These activities are listed, with emphasis on weapons testing programs which do not remain static

  11. Nevada Test Site, Nye County, Nevada. Final environmental impact statement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1977-09-01

    This environmental statement for the Nevada Test Site (NTS) considers underground nuclear detonations with yields of one megaton or less, along with the preparations necessary for such detonations. The testing activities considered also include other continuing and intermittent activities, both nuclear and nonnuclear, which can best be conducted in the remote and controlled area of the Nevada Test Site. These activities are listed, with emphasis on weapons testing programs which do not remain static.

  12. Nevada`s role in the hydrogen economy

    Energy Technology Data Exchange (ETDEWEB)

    Vaeth, T. [Dept. of Energy, Las Vegas, NV (United States)

    1997-12-31

    The paper discusses the promise of hydrogen and its possible applications, barriers to its development, the role that the Nevada Test Site could play if it were made more available to public and private institutions for research, and the ``clean city`` concept being developed jointly with California, Utah, and Nevada. This concept would create a ``clean corridor`` along the route from Salt Lake City through Reno to Sacramento, Los Angeles, Las Vegas, and back to Salt Lake City.

  13. A Preliminary Heat Flow Model for Cooling a Batholith near Ica, Peru

    Science.gov (United States)

    Gonzalez, L. U.; Clausen, B. L.; Molano, J. C.; Martinez, A. M.; Poma, O.

    2014-12-01

    This research models the cooling of a suite in the Linga Super-unit located at the north end of the Arequipa segment in the Cretaceous Peruvian Coastal Batholith. The monzogabbro to granite Linga suite is approximately 50 km long and 15 km wide, with an estimated vertical extent of about 5 km originally intruded to a depth of 3 km. The emplacement was in andesitic volcanics on the west and the Pampahuasi diorite Super-unit on the east and has incorporated earlier gabbroic bodies. The Linga suite is thought to be the result of a sequence of three pulses: an elongate unit to the west then two elliptical units to the northeast and southeast. The data for modeling comes from field observations on internal and external contacts, some well-defined magma chamber walls and roof, pendant and stoped blocks, magma chamber zoning, the nature and distribution of enclaves and xenoliths, magmatic fabric, evidences of magma mingling, rock porosity, mineralogical associations in metamorphic aureoles, extensive mineralization and brecciated conduits, and the types of hydrothermal alteration varying with distance from contacts. More than forty hand samples, thin sections, and geochemical analyses were used to estimate water content, magma and country rock temperature, liquid density, and viscosity. Further data will come from: zircon U-Pb ages for country rock and magma batch timeframes, fluid inclusions for magma pressure and temperature, and δ18O data for source of hydrothermal fluids. Simple heat conduction calculations using MATLAB and HEAT 3D for a single tabular intrusion estimated a cooling time to solidus of about 300 k.y. More complex modeling includes magma convection and multiple intrusions. Extensive veining and pervasive alteration suggested the use of HYDROTHERM to model possible additional heat flow effects from hydrothermal fluids. Extensive propylitic and significant potassic alteration were observed and, with TerraSpec infrared spectroscopy to identify

  14. Experimental and geochemical evidence for derivation of the El Capitan Granite, California, by partial melting of hydrous gabbroic lower crust

    Science.gov (United States)

    Ratajeski, K.; Sisson, T.W.; Glazner, A.F.

    2005-01-01

    Partial melting of mafic intrusions recently emplaced into the lower crust can produce voluminous silicic magmas with isotopic ratios similar to their mafic sources. Low-temperature (825 and 850??C) partial melts synthesized at 700 MPa in biotite-hornblende gabbros from the central Sierra Nevada batholith (Sisson et al. in Contrib Mineral Petrol 148:635-661, 2005) have major-element and modeled trace-element (REE, Rb, Ba, Sr, Th, U) compositions matching those of the Cretaceous El Capitan Granite, a prominent granite and silicic granodiorite pluton in the central part of the Sierra Nevada batholith (Yosemite, CA, USA) locally mingled with coeval, isotopically similar quartz diorite through gabbro intrusions (Ratajeski et al. in Geol Soc Am Bull 113:1486-1502, 2001). These results are evidence that the El Capitan Granite, and perhaps similar intrusions in the Sierra Nevada batholith with lithospheric-mantle-like isotopic values, were extracted from LILE-enriched, hydrous (hornblende-bearing) gabbroic rocks in the Sierran lower crust. Granitic partial melts derived by this process may also be silicic end members for mixing events leading to large-volume intermediate composition Sierran plutons such as the Cretaceous Lamarck Granodiorite. Voluminous gabbroic residues of partial melting may be lost to the mantle by their conversion to garnet-pyroxene assemblages during batholithic magmatic crustal thickening. ?? Springer-Verlag 2005.

  15. Nevada Thickness of Cenozoic Deposits

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study of gravity data from Nevada is part of a statewide analysis of mineral resources. The main objective of the gravity study were: 1) to infer the structure...

  16. Sierra/SolidMechanics 4.48 Verification Tests Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Plews, Julia A.; Crane, Nathan K; de Frias, Gabriel Jose; Le, San; Littlewood, David John; Merewether, Mark Thomas; Mosby, Matthew David; Pierson, Kendall H.; Porter, Vicki L.; Shelton, Timothy; Thomas, Jesse David; Tupek, Michael R.; Veilleux, Michael; Xavier, Patrick G.

    2018-03-01

    Presented in this document is a small portion of the tests that exist in the Sierra / SolidMechanics (Sierra / SM) verification test suite. Most of these tests are run nightly with the Sierra / SM code suite, and the results of the test are checked versus the correct analytical result. For each of the tests presented in this document, the test setup, a description of the analytic solution, and comparison of the Sierra / SM code results to the analytic solution is provided. Mesh convergence is also checked on a nightly basis for several of these tests. This document can be used to confirm that a given code capability is verified or referenced as a compilation of example problems. Additional example problems are provided in the Sierra / SM Example Problems Manual. Note, many other verification tests exist in the Sierra / SM test suite, but have not yet been included in this manual.

  17. Archaeological obsidian from La Sierra Gorda Mexico, by PIXE

    International Nuclear Information System (INIS)

    Juarez-Cossio, D.; Terreros, E.; Quiroz-Moreno, J.; Romero-Sanchez, S.; Calligaro, T.F.; Tenorio, D.; Jimenez-Reyes, M.; Los Rios, M. de

    2009-01-01

    The chemical compositions of 42 obsidian pre-Hispanic artifacts from Tancama and Purisima, both archaeological sites of La Sierra Gorda Valleys, Mexico, were analyzed by PIXE technique. These obsidians came from four sources: Sierra de Pachuca Hidalgo, Paraiso Queretaro, Ucareo Michoacan and mainly from Zacualtipan/Metzquititlan Hidalgo. According to archaeological evidences, La Sierra Gorda valleys participated in commercial exchange with other regional sites, from Classic to Post-classic periods (A.D. 300-1500).

  18. Nevada Test Site Waste Acceptance Criteria

    International Nuclear Information System (INIS)

    U.S. Department of Energy, Nevada Operations Office, Waste Acceptance Criteria

    1999-01-01

    This document provides the requirements, terms, and conditions under which the Nevada Test Site will accept low-level radioactive and mixed waste for disposal; and transuranic and transuranic mixed waste for interim storage at the Nevada Test Site

  19. Sierra Madre Oriental in Coahuila, Mexico

    Science.gov (United States)

    2002-01-01

    This desolate landscape is part of the Sierra Madre Oriental mountain range, on the border between the Coahuila and Nuevo Leon provinces of Mexico. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on November 28, 1999. This is a false-color composite image made using shortwave infrared, infrared, and green wavelengths. The image has also been sharpened using the sensor's panchromatic band. Image provided by the USGS EROS Data Center Satellite Systems Branch

  20. Birds of Sierra de Vallejo, Nayarit, Mexico

    OpenAIRE

    Figueroa-Esquivel, E.M.; Puebla-Olivares, F

    2014-01-01

    Sierra de Vallejo, is considered a priority region for conservation, and is strongly affected by anthropogenic pressures. The inventory of birds are refers to studies in near areas. This study is a concrete contribution of the birds of the mountain chain and north of it. We considered bibliographic records and databases available on the web with records of ocurrence and specimens of scientific collections. Also we perform point counts in different localities inside the...

  1. Nevada Test Site Waste Acceptance Criteria (NTSWAC)

    Energy Technology Data Exchange (ETDEWEB)

    NNSA/NSO Waste Management Project

    2008-06-01

    This document establishes the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, Nevada Test Site Waste Acceptance Criteria (NTSWAC). The NTSWAC provides the requirements, terms, and conditions under which the Nevada Test Site will accept low-level radioactive (LLW) and LLW Mixed Waste (MW) for disposal.

  2. Environmental overview of geothermal development: northern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Slemmons, D.B.; Stroh, J.M.; Whitney, R.A. (eds.)

    1980-08-01

    Regional environmental problems and issues associated with geothermal development in northern Nevada are studied to facilitate environmental assessment of potential geothermal resources. The various issues discussed are: environmental geology, seismicity of northern Nevada, hydrology and water quality, air quality, Nevada ecosystems, noise effects, socio-economic impacts, and cultural resources and archeological values. (MHR)

  3. Nevada Test Site Waste Acceptance Criteria (NTSWAC)

    International Nuclear Information System (INIS)

    NNSA/NSO Waste Management Project

    2008-01-01

    This document establishes the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, Nevada Test Site Waste Acceptance Criteria (NTSWAC). The NTSWAC provides the requirements, terms, and conditions under which the Nevada Test Site will accept low-level radioactive (LLW) and LLW Mixed Waste (MW) for disposal

  4. Oxygen isotope studies of early Precambrian granitic rocks from the Giants Range batholith, northeastern Minnesota, U.S.A.

    Science.gov (United States)

    Viswanathan, S.

    1974-01-01

    Oxygen isotope studies of granitic rocks from the 2.7 b.y.-old composite Giants Range batholith show that: (1) ??(O18)quartz values of 9 to 10 permil characterize relatively uncontaminated Lower Precambrian, magmatic granodiorites and granites; (2) granitic rocks thought to have formed by static granitization have ??(O18)quartz values that are 1 to 2 permil higher than magmatic granitic rocks; (3) satellite leucogranite bodies have values nearly identical to those of the main intrusive phases even where they transect O18-rich metasedimentary wall rocks; (4) oxygen isotopic interaction between the granitic melts and their O18-rich wall rocks was minimal; and (5) O18/O18 ratios of quartz grains in a metasomatic granite are largely inherited from the precursor rock, but during the progression - sedimentary parent ??? partially granitized parent ??? metasomatic granite ??? there is gradual decrease in ??(O18)quartz by 1 to 2 permil. ?? 1974.

  5. Petrological study of the eastern part of Rio Maria batholith located in the SE of Para State

    International Nuclear Information System (INIS)

    Medeiros, H. de.

    1987-01-01

    This work is a petrological and geochronological study in the eastern part of Rio Maria batholith located in the SE of Para State (Brazil), in which granodioritic composition predominates. Selected samples including all varieties present in the eastern portion of Rio Maria granodioritic batholith were analyzed for major, minor and some trace elements. The results suggest two differentiation trends. The first is (BHGd + HBGd) - HBM sub(z)G, with decrease in CaO, TiO sub(2), Fe total, MgO and Sr contents, whereas K2O and Rb increase. The second trend is (BHGd + HBGd) - BGd, where the BGd have the highest values of SiO sub(2), and low CaO, TiO sub(2), Fe total, MgO and Sr contents. This results are in agreement with that obtained to the calc-alkaline rock series. Six selected samples, including all varieties, were dated by the Rb/Sr Whole-rock method, producing a isochronic age of 2564 +- 68 m.y. with an initial Sr sup(87)/Sr sup(86) ratio of 0.70288 +- 00092. The crystallization sequence proposed to the BHGd and BHGd, when correlated to the experimental results obtained in the rocks of granodioritic composition, suggests that the magma crystallization was in low pressure conditions (2 to 4kb). The temperature interval would be between 950 and +- 700 sup(0)C. The best explanation to the granodioritic magma origin is by partial fusion in the crustal base, with contribution of mantle material or not. The association of the rock units, including granodiorites, trondhjemites, meta-volcan-sedimentary sequences and gneisses of tonalitic to granodioritic composition observed in the Rio Maria region, and the Archaeyan ages obtained by the Rb/Sr method suggest that this region can be correlated with granite-greenstone terrains exposed in the Rhodesian, Kaapvaal and western Australia cratons. (author)

  6. Experimental Repatriation of Mountain Yellow-legged Frogs (Rana muscosa) in the Sierra Nevada of California

    Science.gov (United States)

    Fellers, Gary M.; Bradford, David F.; Pratt, David; Wood, Leslie

    2008-01-01

    In the late 1970s, Rana muscosa (mountain yellow-legged frog) was common in the Tableland area of Sequoia National Park, California where it was possible to find hundreds of tadpoles and adults around many of the ponds and lakes. Surveys in 1993-1995 demonstrated that R. muscosa was absent from more than half of all suitable habitat within the park, including the Tableland area. At that same time, R. muscosa was still common at Sixty Lake Basin, Kings Canyon National Park, 30 km to the northeast. To evaluate the potential causes for the extirpation, we repatriated R. muscosa eggs, tadpoles, subadults, and adult frogs from Sixty Lake Basin to four sites in the Tableland area in 1994 and 1995. We subsequently surveyed each release site and the surrounding area 2 - 3 times per week in 1994-1995, and intermittently in 1996-1997, to monitor the survival of all life history stages, and to detect dispersal of adults and subadults. We also monitored predation, water quality, weather, and water temperature. Our techniques for capturing, holding, transporting, and releasing R. muscosa were refined during the study, and during 1995 resulted in high initial survival rates of all life history stages. Adult frogs were anaesthetized, weighed, measured, tagged, and held in plastic boxes with wet paper towels. Tadpoles were collected and held in fiberglass screen cages set in the water at the edge of a pond. This resulted in relatively natural conditions with less crowding and good water circulation. Frogs, tadpoles, and eggs were placed in Ziploc bags for transport to the Tableland by helicopter. Short-term survival of tadpoles, subadults, and adults was high at all four release sites, tadpoles reached metamorphosis, and adult frogs were still present. However, we detected no evidence of reproduction at three sites (e.g., no new eggs or small tadpoles) and nearly all life history stages disappeared within 12 months. At the fourth site, there was limited reproduction, but it was insufficient to maintain a population. It appears that the causal factors for the demise of R. muscosa in the Tableland during the 1970s were still operating in the 1990s or that a new limiting factor has developed. Dispersal, weather, water quality, and predation do not appear to be causative agents; since fish have never been present in the portions of the watershed where we were working, they were not a factor. Observations and data are consistent with the hypotheses that chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis, and/or exposure to airborne pesticides caused both declines. However, at the time of our study, chytridiomycosis had not been described and the potentially significant role of contaminants was largely undocumented.

  7. 78 FR 24471 - Endangered and Threatened Wildlife and Plants; Endangered Status for the Sierra Nevada Yellow...

    Science.gov (United States)

    2013-04-25

    ... patterned with dark spots (Jennings and Hayes 1994, p. 74; Stebbins 2003, p. 233). These spots may be large...). Mountain yellow-legged frogs have smoother skin, generally with heavier spotting and mottling dorsally...

  8. Clearcutting and natural regeneration: management implications for the northern Sierra Nevada

    Science.gov (United States)

    Philip M. McDonald

    1983-01-01

    In the young-mature mixed-conifer and hardwood forests of north-central California, a dense and persistent hardwood understory competes with the conifers for space, nutrients, and water. Clear-cutting with intensive site preparation often is the most appropriate silvicultural regeneration method. This report, the result of 20 years of research on the Challenge...

  9. A broadcast burn in secondgrowth clearcuttings in the north central Sierra Nevada

    Science.gov (United States)

    Philip M. McDonald; Harry E. Schimke

    1966-01-01

    At the Challenge Experimental Forest, 29 acres of slash were broadcast burned on five small clearcut plots (2 to 10 acres) at a cost of $57.00 per acre. Fuel-weight measurements showed reductions of 68 to 84 percent after the burn. Modifications to plot size, shape, and orientation could reduce this cost.

  10. A climate change primer for land managers: an example from the Sierra Nevada

    Science.gov (United States)

    Toni Lyn Morelli; Maureen C. McGlinchy; Ronald P. Neilson

    2011-01-01

    Interest in location-specific climate projections is growing. To facilitate the communication of these data, we provide here an example for how to present climate information relevant at the scale of a national forest. We summarize some of the latest data on climate change projections and impacts relevant to eastern California, from the global scale to the state level...

  11. Fuel treatment effects on modeled landscape level fire behavior in the northern Sierra Nevada

    Science.gov (United States)

    J.J. Moghaddas; B.M. Collins; K. Menning; E.E.Y. Moghaddas; S.L. Stephens

    2010-01-01

    Across the western United States, decades of fire exclusion combined with past management history have contributed to the current condition of extensive areas of high-density, shade-tolerant coniferous stands that are increasingly prone to high-severity fires. Here, we report the modeled effects of constructed defensible fuel profile zones and group selection...

  12. 76 FR 9595 - Notice of Public Meetings: Sierra Front Northwestern Basin Resource Advisory Council, Nevada

    Science.gov (United States)

    2011-02-18

    ... Plant, LiDAR (Optical Remote-Sensing Technology) Virtual Tour of Hidden Cave, Hidden Cave and Grimes... proposals and RAC-hosted public comment, landscape approach/land health assessment processes, impacts to...

  13. Origins and composition of fine atmospheric carbonaceous aerosol in the Sierra Nevada Mountains, California

    Directory of Open Access Journals (Sweden)

    D. R. Worton

    2011-10-01

    Full Text Available In this paper we report chemically resolved measurements of organic aerosol (OA and related tracers during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX at the Blodgett Forest Research Station, California from 15 August–10 October 2007. OA contributed the majority of the mass to the fine atmospheric particles and was predominately oxygenated (OOA. The highest concentrations of OA were during sporadic wildfire influence when aged plumes were impacting the site. In situ measurements of particle phase molecular markers were dominated by secondary compounds and along with gas phase compounds could be categorized into six factors or sources: (1 aged biomass burning emissions and oxidized urban emissions, (2 oxidized urban emissions (3 oxidation products of monoterpene emissions, (4 monoterpene emissions, (5 anthropogenic emissions and (6 local methyl chavicol emissions and oxidation products. There were multiple biogenic components that contributed to OA at this site whose contributions varied diurnally, seasonally and in response to changing meteorological conditions, e.g. temperature and precipitation events. Concentrations of isoprene oxidation products were larger when temperatures were higher during the first half of the campaign (15 August–12 September due to more substantial emissions of isoprene and enhanced photochemistry. The oxidation of methyl chavicol, an oxygenated terpene emitted by ponderosa pine trees, contributed similarly to OA throughout the campaign. In contrast, the abundances of monoterpene oxidation products in the particle phase were greater during the cooler conditions in the latter half of the campaign (13 September–10 October, even though emissions of the precursors were lower, although the mechanism is not known. OA was correlated with the anthropogenic tracers 2-propyl nitrate and carbon monoxide (CO, consistent with previous observations, while being comprised of mostly non-fossil carbon (>75%. The correlation between OA and an anthropogenic tracer does not necessarily identify the source of the carbon as being anthropogenic but instead suggests a coupling between the anthropogenic and biogenic components in the air mass that might be related to the source of the oxidant and/or the aerosol sulfate. Observations of organosulfates of isoprene and α-pinene provided evidence for the likely importance of aerosol sulfate in spite of neutralized aerosol although acidic plumes might have played a role upwind of the site. This is in contrast to laboratory studies where strongly acidic seed aerosols were needed in order to form these compounds. These compounds together represented only a minor fraction (<1% of the total OA mass, which may be the result of the neutralized aerosol at the site or because only a small number of organosulfates were quantified. The low contribution of organosulfates to total OA suggests that other mechanisms, e.g. NOx enhancement of oxidant levels, are likely responsible for the majority of the anthropogenic enhancement of biogenic secondary organic aerosol observed at this site.

  14. ANNUAL OZONE DEPOSITION TO A PONDEROSA PINE PLANTATION IN THE SIERRA NEVADA MOUNTAINS. (R826601)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  15. A Multi-stakeholder Approach to Moving Beyond Tree Mortality in the Sierra Nevada

    Science.gov (United States)

    Balachowski, J.; Buluc, L.; Fischer, C.; Ko, J.; Ostoja, S.

    2017-12-01

    The US Forest Service has estimated that 102 million trees have died in California since 2010. This die off event has been attributed to the combined effects of historical land management practices, fire suppression, insect outbreaks, and climate-related stressors. This tree mortality event represents the largest and most significant ecological disturbance in California in centuries, if not longer. Both scientists and managers recognize the need to rethink our approach to forest management in the face of a changing climate and increasingly frequent, uncharacteristically large wildfires, while budgets and staffing capacity continue to decrease. Addressing the uncertainly in managing under climate change with fewer financial resources will require multiple partners and stakeholders—including federal and state agencies, local governments, and non-governmental organizations—to work together to identify common goals and paths moving forward. The USDA California Climate Hub and USFS Region 5 convened a symposium on drought and tree mortality in July 2017. With nearly 170 attendees across a wide range of sectors, the event provided a meaningful opportunity for reflection, analysis, and consideration of next steps. Among the outcomes of this symposium was the identification of areas in which our capacity for individual and synergistic action is stronger, and those in which it is lacking that will thus require additional attention and effort. From this symposium, which included a series of smaller, stakeholder and partner working groups, we collectively identified research and information needs, possible policy adjustments, future management actions, and funding needs and opportunities. Here, we present these findings and suggest approaches for addressing the current tree mortality event based on the shared interests of multiple, diverse stakeholder groups.

  16. Population dynamics of dwarf mistletoe on young true firs in the central Sierra Nevada, California

    Science.gov (United States)

    Robert E Scharpf; J. R. Jr. Parmeter

    1982-01-01

    Young red firs (Abies magnifica A. Murr.) and white firs (A. concolor [Gord. & Glend.] Lindl. ex Hildebr.) on the Stanislaus National Forest, California, were inoculated with seeds of dwarf mistletoe (Arceuthobium abietinum) for 5 successive years. Only 3 to 4 percent of about 7000 seeds placed on branches...

  17. Impacts of Aerosols on the Retreat of the Sierra Nevada Glaciers in California

    Science.gov (United States)

    El-Askary, H. M.; Li, J.; Ta, T. N.; Jong, A.; Zhang, X.

    2015-12-01

    Natural dust aerosol is an active component of the climate system and plays multiple roles in physical climate and bio-geo-chemical exchanges between the atmosphere, land surface and ocean. Aerosol deposition on snow is amongst the different causes of glacier retreat around the world as well as the reduction of snow albedo. We have observed a long range transport of dust and pollution aerosols from China to the U.S. In this paper we compared summer and winter seasons glacier changes between 2000 and 2013, and how the dust aerosol change over this 13 years. Multiple images, acquired from Landsat-5 TM, Landsat-7 ETM+ and Landsat-8 OLI were used in the study. The change detection analysis was employed to identify the glacier changes for two seasons. The results suggest that the glacier decreased dramatically over 13 years in both seasons.

  18. Air Quality at Devils Postpile National Monument, Sierra Nevada Mountains, California, USA

    Science.gov (United States)

    Joel D. Burley; Andrzej Bytnerowicz; Monica Buhler; Barbara Zielinska; Donald Schweizer; Ricardo Cisneros; Susan Schilling; Jennifer Chapman Varela; Mark McDaniel; Michelle Horn; Deanna Dulen

    2016-01-01

    Ambient concentrations of O3, PM2.5, NH3, NO, NO2, HNO3, SO2 and VOCs were measured at Devils Postpile National Monument (DEPO) during the summer seasons of 2013 and 2014. The measurements were impacted by the Aspen and Rim Fires in...

  19. Conceptual model of sediment processes in the upper Yuba River watershed, Sierra Nevada, CA

    Science.gov (United States)

    Curtis, J.A.; Flint, L.E.; Alpers, Charles N.; Yarnell, S.M.

    2005-01-01

    This study examines the development of a conceptual model of sediment processes in the upper Yuba River watershed; and we hypothesize how components of the conceptual model may be spatially distributed using a geographical information system (GIS). The conceptual model illustrates key processes controlling sediment dynamics in the upper Yuba River watershed and was tested and revised using field measurements, aerial photography, and low elevation videography. Field reconnaissance included mass wasting and channel storage inventories, assessment of annual channel change in upland tributaries, and evaluation of the relative importance of sediment sources and transport processes. Hillslope erosion rates throughout the study area are relatively low when compared to more rapidly eroding landscapes such as the Pacific Northwest and notable hillslope sediment sources include highly erodible andesitic mudflows, serpentinized ultramafics, and unvegetated hydraulic mine pits. Mass wasting dominates surface erosion on the hillslopes; however, erosion of stored channel sediment is the primary contributor to annual sediment yield. We used GIS to spatially distribute the components of the conceptual model and created hillslope erosion potential and channel storage models. The GIS models exemplify the conceptual model in that landscapes with low potential evapotranspiration, sparse vegetation, steep slopes, erodible geology and soils, and high road densities display the greatest hillslope erosion potential and channel storage increases with increasing stream order. In-channel storage in upland tributaries impacted by hydraulic mining is an exception. Reworking of stored hydraulic mining sediment in low-order tributaries continues to elevate upper Yuba River sediment yields. Finally, we propose that spatially distributing the components of a conceptual model in a GIS framework provides a guide for developing more detailed sediment budgets or numerical models making it an inexpensive way to develop a roadmap for understanding sediment dynamics at a watershed scale.

  20. Soil carbon storages and erosional exports along a forested denudation gradient in the Sierra Nevada, California

    Science.gov (United States)

    Yoo, K.; Wang, X.; Mudd, S. M.; Weinman, B.; Gutknecht, J.; Gabet, E. J.

    2017-12-01

    Eroding uplands not only provide physically mixed soil zones where OC and minerals actively interact but also are the significant sources of suspended sediments and organic carbon (OC) to rivers. Here our goal is to quantify the extents that erosion affects soils' capacities to store OC in different degrees of mineral-association and to facilitate the exports of minerals that might capture OC on their reactive surfaces. We examined a tributary basin to the Middle Folk Feather River in California, where knickpoint migration has created a series of hillslopes with erosion rates varying from 35 to 250 mm kyr-1. Other than erosion rates, the studied hillslopes within the tributary basin shared similar environmental factors. Soil samples were collected from select hillslopes that differ in their relative positions to knikpoints and were subject to size and density fractionation. Despite the substantial difference in erosion rates, concentrations of particulate OC (POC) and mineral-associated OC (MOC) and soil thickness varied little. Instead, considerable increase in coarse rock contents positively associated with erosion rate was responsible for the reduction of soil OC inventories by 37% with increasing erosion rate. In contrast to consistent MOC concentrations across the erosion gradient, clay contents in soils are negatively correlated with erosion rates. This seemingly contradictory result, however, is consistent with BET mineral specific surface area that remains insensitive to erosion rates. OC coverage on mineral surface was found to be less than affects the soil carbon cycle.

  1. 75 FR 44942 - 2015 Resource Pool-Sierra Nevada Customer Service Region

    Science.gov (United States)

    2010-07-30

    ... California State University, Sacramento. 0.06140 2,052 Cawelo Water District 0.06140 2,052 Dry Creek...,052 South San Joaquin Irrigation District... 0.01400 468 Stockton, Port of 0.02421 809 Truckee Donner...

  2. Predicted fire behavior and societal benefits in three eastern Sierra Nevada vegetation types

    Science.gov (United States)

    C.A. Dicus; K. Delfino; D.R. Weise

    2009-01-01

    We investigated potential fire behavior and various societal benefits (air pollution removal, carbon sequestration, and carbon storage) provided by woodlands of pinyon pine (Pinus monophylla) and juniper (Juniperus californica), shrublands of Great Basin sagebrush (Artemisia tridentata) and rabbitbrush (Ericameria nauseosa...

  3. Nonlocal Sediment Transport on Steep Lateral Moraines, Eastern Sierra Nevada, California, USA

    Science.gov (United States)

    Doane, Tyler H.; Furbish, David Jon; Roering, Joshua J.; Schumer, Rina; Morgan, Daniel J.

    2018-01-01

    Recent work has highlighted the significance of long-distance particle motions in hillslope sediment transport. Such motions imply that the flux at a given hillslope position is appropriately described as a weighted function of surrounding conditions that influence motions reaching the given position. Although the idea of nonlocal sediment transport is well grounded in theory, limited field evidence has been provided. We test local and nonlocal formulations of the flux and compare their ability to reproduce land surface profiles of steep moraines in California. We show that nonlocal and nonlinear models better reproduce evolved land surface profiles, notably the amount of lowering and concavity near the moraine crest and the lengthening and straightening of the depositional apron. The analysis provides the first estimates of key parameters that set sediment entrainment rates and travel distances in nonlocal formulations and highlights the importance of correctly specifying the entrainment rate when modeling land surface evolution. Moraine evolution associated with nonlocal and nonlinear transport formulations, when described in terms of the evolution of the Fourier transform of the moraine surface, displays a distinct behavior involving growth of certain wave numbers, in contrast to the decay of all wave numbers associated with linear transport. Nonlinear and nonlocal formulations share key mathematical elements yielding a nonlinear relation between the flux and the land surface slope.

  4. CUES – A Study Site for Measuring Snowpack Energy Balance in the Sierra Nevada

    Directory of Open Access Journals (Sweden)

    Edward H. Bair

    2015-09-01

    Full Text Available Accurate measurement and modeling of the snowpack energy balance are critical to understanding the terrestrial water cycle. Most of the water resources in the western US come from snowmelt, yet statistical runoff models that rely on the historical record are becoming less reliable because of a changing climate. For physically based snow melt models that do not depend on past conditions, ground based measurements of the energy balance components are imperative for verification. For this purpose, the US Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL and the University of California, Santa Barbara (UCSB established the CUES snow study site (CRREL/UCSB Energy Site, http://www.snow.ucsb.edu/ at 2940 m elevation on Mammoth Mountain, California. We describe CUES, provide an overview of research, share our experience with scientific measurements, and encourage future collaborative research. Snow measurements began near the current CUES site for ski area operations in 1969. In the 1970s, researchers began taking scientific measurements. Today, CUES benefits from year round gondola access and a fiber optic internet connection. Data loggers and computers automatically record and store over 100 measurements from more than 50 instruments each minute. CUES is one of only five high altitude mountain sites in the Western US where a full suite of energy balance components are measured. In addition to measuring snow on the ground at multiple locations, extensive radiometric and meteorological measurements are recorded. Some of the more novel measurements include scans by an automated terrestrial LiDAR, passive and active microwave imaging of snow stratigraphy, microscopic imaging of snow grains, snowflake imaging with a multi-angle camera, fluxes from upward and downward looking radiometers, snow water equivalent from different types of snow pillows, snowmelt from lysimeters, and concentration of impurities in the snowpack. We give an example of terrain-corrected snow albedo measurements compared to several models and of sublimation measured from lysimeter and snow pillow melt. We conclude with some thoughts on the future of CUES.

  5. CUES - A Study Site for Measuring Snowpack Energy Balance in the Sierra Nevada

    Science.gov (United States)

    Bair, Edward; Dozier, Jeff; Davis, Robert; Colee, Michael; Claffey, Keran

    2015-09-01

    Accurate measurement and modeling of the snowpack energy balance are critical to understanding the terrestrial water cycle. Most of the water resources in the western US come from snowmelt, yet statistical runoff models that rely on the historical record are becoming less reliable because of a changing climate. For physically based snow melt models that do not depend on past conditions, ground based measurements of the energy balance components are imperative for verification. For this purpose, the US Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL) and the University of California, Santa Barbara (UCSB) established the “CUES” snow study site (CRREL/UCSB Energy Site, http://www.snow.ucsb.edu/) at 2940 m elevation on Mammoth Mountain, California. We describe CUES, provide an overview of research, share our experience with scientific measurements, and encourage future collaborative research. Snow measurements began near the current CUES site for ski area operations in 1969. In the 1970s, researchers began taking scientific measurements. Today, CUES benefits from year round gondola access and a fiber optic internet connection. Data loggers and computers automatically record and store over 100 measurements from more than 50 instruments each minute. CUES is one of only five high altitude mountain sites in the Western US where a full suite of energy balance components are measured. In addition to measuring snow on the ground at multiple locations, extensive radiometric and meteorological measurements are recorded. Some of the more novel measurements include scans by an automated terrestrial LiDAR, passive and active microwave imaging of snow stratigraphy, microscopic imaging of snow grains, snowflake imaging with a multi-angle camera, fluxes from upward and downward looking radiometers, snow water equivalent from different types of snow pillows, snowmelt from lysimeters, and concentration of impurities in the snowpack. We give an example of terrain-corrected snow albedo measurements compared to several models and of sublimation measured from lysimeter and snow pillow melt. We conclude with some thoughts on the future of CUES.

  6. Historical and contemporary distributions of carnivores in forests of the Sierra Nevada, California, USA

    Science.gov (United States)

    William J Zielinski; Richard L Truex; Fredrick V. Schlexer; Lori A. Campbell; Carlos Caroll

    2005-01-01

    Malammalian carnivores are considered particularly sensitive indicators of environmental change. Information on the distribution of carnivores from the early 1900s provides a unique opportunity to evaluate changes in their distributions over a 75-year period during which the influence of human uses of forest resources in California greatly increased. We present...

  7. Soil moisture response to snowmelt and rainfall in a Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    Roger C. Bales; Jan W. Hopmans; Anthony T. O’Geen; Matthew Meadows; Peter C. Hartsough; Peter Kirchner; Carolyn T. Hunsaker; Dylan. Beaudette

    2011-01-01

    Using data from a water-balance instrument cluster with spatially distributed sensors we determined the magnitude and within-catchment variability of components of the catchment-scale water balance, focusing on the relationship of seasonal evapotranspiration to changes in snowpack and soil moisture storage. Co-located, continuous snow depth and soil moisture...

  8. Accumulation of pesticides in pacific chorus frogs (Pseudacris regilla) from California's Sierra Nevada Mountains, USA

    Science.gov (United States)

    Smalling, Kelly L.; Fellers, Gary M.; Kleeman, Patrick M.; Kuivila, Kathryn

    2013-01-01

    Pesticides are receiving increasing attention as potential causes of amphibian declines, acting singly or in combination with other stressors, but limited information is available on the accumulation of current-use pesticides in tissue. The authors examined potential exposure and accumulation of currently used pesticides in pond-breeding frogs (Pseudacris regilla) collected from 7 high elevations sites in northern California. All sites sampled are located downwind of California's highly agricultural Central Valley and receive inputs of pesticides through precipitation and/or dry deposition. Whole frog tissue, water, and sediment were analyzed for more than 90 current-use pesticides and pesticide degradates using gas chromatography–mass spectrometry. Two fungicides, pyraclostrobin and tebuconazole, and one herbicide, simazine, were the most frequently detected pesticides in tissue samples. Median pesticide concentration ranged from 13 µg/kg to 235 µg/kg wet weight. Tebuconazole and pyraclostrobin were the only 2 compounds observed frequently in frog tissue and sediment. Significant spatial differences in tissue concentration were observed, which corresponded to pesticide use in the upwind counties. Data generated indicated that amphibians residing in remote locations are exposed to and capable of accumulating current-use pesticides. A comparison of P. regilla tissue concentrations with water and sediment data indicated that the frogs are accumulating pesticides and are potentially a more reliable indicator of exposure to this group of pesticides than either water or sediment.

  9. Increasing resiliency in frequent fire forests: Lessons from the Sierra Nevada and western Australia

    Science.gov (United States)

    Scott L. Stephens

    2014-01-01

    This paper will primarily focus on the management and restoration of forests adapted to frequent, low-moderate intensity fire regimes. These are the forest types that are most at risk from large, high-severity wildfires and in many regions their fire regimes are changing. Fire as a landscape process can exhibit self-limiting characteristics in some forests which can...

  10. Restoring surface fire stabilizes forest carbon under extreme fire weather in the Sierra Nevada

    Science.gov (United States)

    Daniel J. Krofcheck; Matthew D. Hurteau; Robert M. Scheller; E. Louise Loudermilk

    2017-01-01

    Climate change in the western United States has increased the frequency of extreme fire weather events and is projected to increase the area burned by wildfire in the coming decades. This changing fire regime, coupled with increased high-severity fire risk from a legacy of fire exclusion, could destabilize forest carbon (C), decrease net ecosystem exchange (...

  11. Non-native fish introductions and the reversibility of amphibian declines in the Sierra Nevada

    Science.gov (United States)

    Roland A. Knapp

    2004-01-01

    Amphibians are declining worldwide for a variety of reasons, including habitat alteration, introduction of non-native species, disease, climate change, and environmental contaminants. Amphibians often play important roles in structuring ecosystems, and, as a result, amphibian population declines or extinctions are likely to affect other trophic levels (Matthews and...

  12. Forest biomass diversion in the Sierra Nevada: Energy, economics and emissions

    Science.gov (United States)

    Bruce Springsteen; Thomas Christofk; Robert A. York; Tad Mason; Stephen Baker; Emily Lincoln; Bruce Hartsough; Takuyuki Yoshioka

    2015-01-01

    As an alternative to open pile burning, use of forest wastes from fuel hazard reduction projects at Blodgett Forest Research Station for electricity production was shown to produce energy and emission benefits: energy (diesel fuel) expended for processing and transport was 2.5% of the biomass fuel (energy equivalent); based on measurements from a large pile...

  13. Nevada local government revenues analysis

    International Nuclear Information System (INIS)

    1988-06-01

    This report analyzes the major sources of revenue for Nevada local government for purposes of estimating the impacts associated with the siting of a nuclear waste repository at Yucca Mountain. Each major revenue source is analyzed separately to identify relationships between the economic or demographic base, the revenue base and the revenues generated. Trends and changes in the rates and/or base are highlighted. A model is developed for each component to allow impact estimation. This report is a companion to the report Nevada State Revenues Analysis

  14. Residential Energy Efficiency Potential: Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Eric J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-16

    Energy used by Nevada single-family homes that can be saved through cost-effective improvements. Prepared by Eric Wilson and Noel Merket, NREL, and Erin Boyd, U.S. Department of Energy Office of Energy Policy and Systems Analysis.

  15. Structure of the Alpujarrides on the southern and eastern border of the Sierra de Lújar

    Directory of Open Access Journals (Sweden)

    Tubía, J. M.

    1990-08-01

    Full Text Available The Alpujarride complex located to the South of the Sierra Nevada and extending between Motril and Adra is formed of five nappes, which in ascending order are: Lújar, Cástaras, Alcázar, Murtas and Adra. These five nappes display a structure that is the result of several overlapping events. Firstly, they reflect a process of ductile shearing associated with a mylonitic foliation and a mylonitic lineation with a N4üo E average orientation. Following this, an episode of translation towards the North has been recorded; this occurred under more superficial conditions and developed gouges and fault breccias. Associated with this episode are locally developed folds, which did not give rise to a mineral blastesis. Afterwards, the late deformations occurred, affecting the whole ofthe ensemble. Of these, the most important are those that originated folds with a N-S axis, verging towards the West and the normal faults. The extensional faults towards the South would be encompassed in this sectionEl Complejo Alpujárride situado al Sur de Sierra Nevada y comprendido entre Motril y Adra, está formado por cinco mantos que son, en orden ascendente: Lújar, Cástaras, Alcázar, Murtas y Adra. Estos cinco mantos presentan una estructuración que es el resultado de varios acontecimientos superpuestos. En primer lugar, reflejan un proceso de cizallamiento dúctil hacia el NE, que lleva asociado una foliación milonítica, de orientación media N4üo E. A continuación se ha registrado un episodio de traslaciones hacia el Norte, en condiciones más superficiales, que desarrolla brechas y harinas de falla. Asociado a este episodio se desarrollan localmente pliegues, que no dan lugar a una blastesis mineral. Con posterioridad se producen las deformaciones tardías, que afectan a todo el conjunto. De ellas, las más sobresalientes son las que originan pliegues de eje N-S, vergentes al Oeste y las fallas normales. Las fallas extensionales hacia el Sur quedar

  16. Finding Spectral Patterns in Bark Beetle Infestations in the Sierra National Forest Using Landsat and AVIRIS Imagery

    Science.gov (United States)

    Heck, M. D.; Roberts, D. A.; Miller, D. L.; Tane, Z.

    2016-12-01

    Under normal circumstances, the bark beetles of the Sierra Nevada conifer forests are vital to ecosystem health; by eliminating weak trees, they allow other plants to grow in the space left behind, provide homes for various animals, and enrich the soil. However, climate change is putting these ecosystems at risk: warmer winters allow bark beetles to be active and breed year-round, and the severe drought conditions currently present in California leave otherwise healthy trees unable to defend against attacks. In this study, we used Google Earth and Landsat-8 imagery of the Sierra National Forest to locate trees that had been damaged by bark beetles between the summers of 2015 and 2016. Additionally, we used an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) image from summer of 2015 to look for a difference in the spectra of consistently healthy trees compared to spectra of trees which appeared healthy in 2015 but died in 2016. We found that healthy trees were consistently brighter across the spectrum than dying trees. Comparisons using t-tests were made between elevations, slopes, aspects, and spectral indices of a form (Band 1 - Band 2)/(Band 1 + Band 2) on our AVIRIS data. While we were unable to find any specific indices which indicate beetle kills, wavelengths in the ranges of 400-500 and 2200-2500 nanometers showed the most sensitivity when the brightness difference was scaled and removed.

  17. Structural Evolution of the East Sierra Valley System (Owens Valley and Vicinity, California: A Geologic and Geophysical Synthesis

    Directory of Open Access Journals (Sweden)

    Richard J. Blakely

    2013-04-01

    Full Text Available The tectonically active East Sierra Valley System (ESVS, which comprises the westernmost part of the Walker Lane-Eastern California Shear Zone, marks the boundary between the highly extended Basin and Range Province and the largely coherent Sierra Nevada-Great Valley microplate (SN-GVm, which is moving relatively NW. The recent history of the ESVS is characterized by oblique extension partitioned between NNW-striking normal and strike-slip faults oriented at an angle to the more northwesterly relative motion of the SN-GVm. Spatially variable extension and right-lateral shear have resulted in a longitudinally segmented valley system composed of diverse geomorphic and structural elements, including a discontinuous series of deep basins detected through analysis of isostatic gravity anomalies. Extension in the ESVS probably began in the middle Miocene in response to initial westward movement of the SN-GVm relative to the Colorado Plateau. At ca. 3–3.5 Ma, the SN-GVm became structurally separated from blocks directly to the east, resulting in significant basin-forming deformation in the ESVS. We propose a structural model that links high-angle normal faulting in the ESVS with coeval low-angle detachment faulting in adjacent areas to the east.

  18. Structural evolution of the east Sierra Valley system (Owens Valley and vicinity), California: a geologic and geophysical synthesis

    Science.gov (United States)

    Stevens, Calvin H.; Stone, Paul; Blakely, Richard J.

    2013-01-01

    The tectonically active East Sierra Valley System (ESVS), which comprises the westernmost part of the Walker Lane-Eastern California Shear Zone, marks the boundary between the highly extended Basin and Range Province and the largely coherent Sierra Nevada-Great Valley microplate (SN-GVm), which is moving relatively NW. The recent history of the ESVS is characterized by oblique extension partitioned between NNW-striking normal and strike-slip faults oriented at an angle to the more northwesterly relative motion of the SN-GVm. Spatially variable extension and right-lateral shear have resulted in a longitudinally segmented valley system composed of diverse geomorphic and structural elements, including a discontinuous series of deep basins detected through analysis of isostatic gravity anomalies. Extension in the ESVS probably began in the middle Miocene in response to initial westward movement of the SN-GVm relative to the Colorado Plateau. At ca. 3-3.5 Ma, the SN-GVm became structurally separated from blocks directly to the east, resulting in significant basin-forming deformation in the ESVS. We propose a structural model that links high-angle normal faulting in the ESVS with coeval low-angle detachment faulting in adjacent areas to the east.

  19. Birds of Sierra de Vallejo, Nayarit, Mexico

    Directory of Open Access Journals (Sweden)

    Figueroa-Esquivel, E.M.

    2014-01-01

    Full Text Available Sierra de Vallejo, is considered a priority region for conservation, and is strongly affected by anthropogenic pressures. The inventory of birds are refers to studies in near areas. This study is a concrete contribution of the birds of the mountain chain and north of it. We considered bibliographic records and databases available on the web with records of ocurrence and specimens of scientific collections. Also we perform point counts in different localities inside the reserve. We observed a richness of 261 birds species, the family Tyrannidae is the best represented. Of the species recorded, 177 are permanent residents (31 are endemic and 15 are quasi-endemics to Mexico and 73 are migratory; the remaining eleven records have other status. Also 43 species are in endangered categories. We include species that have not been recorded in the lists of the area and records of species expand their ranges at Nayarit. Due to the great diversity of birds observed, it is necesary to continue the research work about habitat use, abundance and monitoring, it will provides the basis for the conservation of birds of Sierra de Vallejo.

  20. Multiple magmatic pulses of the Eastern Volcano-Plutonic Complex, Krušné hory/ Erzgebirge batholith, and their phosphorus contents

    Czech Academy of Sciences Publication Activity Database

    Štemprok, M.; Holub, F. V.; Novák, Jiří Karel

    2003-01-01

    Roč. 78, č. 3 (2003), s. 277-296 ISSN 1214-1119 R&D Projects: GA ČR GA205/95/0149 Grant - others:GA UK(CZ) 165/1998 Institutional research plan: CEZ:AV0Z3013912 Keywords : volcano-plutonic complex * phosphorus * Krušné hory Mts. batholith Subject RIV: DB - Geology ; Mineralogy http://www.geology.cz/bulletin/contents/2003/vol78no3/bulgeosci200303277.pdf

  1. Acid-neutralizing potential of minerals in intrusive rocks of the Boulder batholith in northern Jefferson County, Montana

    Science.gov (United States)

    Desborough, George A.; Briggs, Paul H.; Mazza, Nilah; Driscoll, Rhonda

    1998-01-01

    Experimental studies show that fresh granitic rocks of the Boulder batholith in the Boulder River headwaters near Basin, Montana have significant acid-neutralizing potential and are capable of neutralizing acidic water derived from metal-mining related wastes or mine workings. Laboratory studies show that in addition to the acidneutralizing potential (ANP) of minor amounts of calcite in these rocks, biotite, tremolite, and feldspars will contribute significantly to long-term ANP. We produced 0.45 micrometer-filtered acidic (pH = 2.95) leachate for use in these ANP experiments by exposing metal-mining related wastes to deionized water in a waste:leachate ratio of 1:20. We then exposed these leachates to finely-ground and sized fractions of batholith rocks, and some of their mineral fractions for extended and repeated periods, for which results are reported here. The intent was to understand what reactions of metal-rich acidic water and fresh igneous rocks would produce. The reactions between the acidic leachates and the bulk rocks and mineral fractions are complex. Factors such as precipitation of phases like Fe-hydroxides and Alhydroxides and the balance between dissolved cations and anions that are sulfate dominated complicate analysis of the results. Research by others of acid neutralization by biotite and tremolite attributed a rise in pH to proton (H+) adsorption in sites vacated by K, Mg, and Ca. Destruction of the silicate framework and liberation of associated structural hydroxyl ions may contribute to ANP. Studies by others have indicated that the conversion of biotite to a vermiculite-type structure by removal of K at a pH of 4 consumes about six protons for every mole of biotite, but at a pH of 3 there is pronounced dissolution of the tetrahedral lattice. The ANP of fresh granitic rocks is much higher than anticipated. The three bulk Boulder igneous rock samples studied have minimum ANP equivalent to about 10-14 weight percent calcite. This ANP is in

  2. Radiometric, magnetic, and gravity study of the Quixadá batholith, central Ceará domain (NE Brazil): evidence for Pan-African/Brasiliano extension-controlled emplacement

    Science.gov (United States)

    Lopes de Castro, David; Mariano Gomes Castelo Branco, Raimundo; Martins, Guttenberg; Araújo de Castro, Neivaldo

    2002-10-01

    A geophysical survey was conducted in the central Ceará domain of the Borborema Province (NE Brazil). The aim of this investigation was to find geophysical evidence for the emplacement of the Quixadá batholith, which is a granitic body probably situated in the local extensional site in the oblique collisional regime of the Pan-African/Brasiliano collage. Remote sensing and airborne geophysical data provided information on the regional deformation that affected the intrusion and surrounding country rocks. In addition, a gravity study was used to determine the three-dimensional geometry and constrain the emplacement model of the Quixadá granite at depth. The trajectories of structural and magnetic lineaments suggest that the regional deformation is strongly influenced by dextral transcurrent movements of the major shear zones. The batholith, which shows an unusual positive gravity anomaly and a low U counts, displays a subhorizontal floor with several gently dipping areas, which are interpreted as magma feeder channels. The 2300 m thick root zones are roughly aligned with NE-SW-trending shear zones. Finally, the internal architecture of the pluton suggests that the Quixadá batholith was emplaced in a dilational shear zone tip area at the north end of Quixeramobim shear zone.

  3. A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation

    Science.gov (United States)

    Phillips, Jeffrey D.; Burton, Bethany L.; Curry-Elrod, Erika; Drellack, Sigmund

    2014-01-01

    The Nevada National Security Site (NNSS, formerly the Nevada Test Site) is located in southern Nevada approximately 105 kilometers (km) (65 miles) northwest of Las Vegas. Frenchman Flat is a sedimentary basin located on the eastern edge of NNSS and extending eastward into the adjacent Nevada Test and Training Range (NTTR).

  4. NEVADA TEST SITE WASTE ACCEPTANCE CRITERIA

    International Nuclear Information System (INIS)

    U.S. DEPARTMENT OF ENERGY, NATIONAL NUCLEAR SECURITY ADMINISTRATION, NEVADA SITE OFFICE

    2005-01-01

    This document establishes the U. S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO) waste acceptance criteria (WAC). The WAC provides the requirements, terms, and conditions under which the Nevada Test Site will accept low-level radioactive and mixed waste for disposal. Mixed waste generated within the State of Nevada by NNSA/NSO activities is accepted for disposal. It includes requirements for the generator waste certification program, characterization, traceability, waste form, packaging, and transfer. The criteria apply to radioactive waste received at the Nevada Test Site Area 3 and Area 5 Radioactive Waste Management Site for storage or disposal

  5. Nevada may lose nuclear waste funds

    International Nuclear Information System (INIS)

    Marshall, E.

    1988-01-01

    The people of Nevada are concerned that a cut in DOE funding for a nuclear waste repository at Yucca Mountain, Nevada will result in cuts in the state monitoring program, e.g. dropping a seismic monitoring network and a sophisticated drilling program. Economic and social impact studies will be curtailed. Even though a provision to curtail local research forbids duplication of DOE's work and would limit the ability of Nevada to go out an collect its own data, Nevada State University at Las Vegas would receive a nice plum, a top-of-the-line supercomputer known as the ETA-10 costing almost $30 million financed by DOE

  6. Projected treatment capacity needs in sierra leone.

    Science.gov (United States)

    White, Richard A; MacDonald, Emily; de Blasio, Birgitte Freiesleben; Nygård, Karin; Vold, Line; Røttingen, John-Arne

    2015-01-30

    The ongoing outbreak of Ebola Virus Disease in West Africa requires immediate and sustained input from the international community in order to curb transmission. The CDC has produced a model that indicates that to end the outbreak by pushing the reproductive number below one, 25% of the patients must be placed in an Ebola Treatment Unit (ETC) and 45% must be isolated in community settings in which risk of disease transmission is reduced and safe burials are provided. In order to provide firmer targets for the international response in Sierra Leone, we estimated the national and international personnel and treatment capacity that may be required to reach these percentages. We developed a compartmental SEIR model that was fitted to WHO data and local data allowing the reproductive number to change every 8 weeks to forecast the progression of the EVD epidemic in Sierra Leone. We used the previously estimated 2.5x correction factor estimated by the CDC to correct for underreporting. Number of personnel required to provide treatment for the predicted number of cases was estimated using UNMEER and UN OCHA requests for resources required to meet the CDC target of 70% isolation. As of today (2014-12-04), we estimate that there are 810 (95% CI=646 to 973) EVD active cases in treatment, with an additional 3751 (95% CI=2778 to 4723) EVD cases unreported and untreated. To reach the CDC targets today, we need 1140 (95% CI=894 to 1387) cases in ETCs and 2052 (95% CI=1608 to 2496) at home or in a community setting with a reduced risk for disease transmission. In 28 days (2015-01-01), we will need 1309 (95% CI=804 to 1814) EVD cases in ETCs and 2356 (95% CI=1447 to 3266) EVD cases at reduced risk of transmission. If the current transmission rate is not reduced, up to 3183 personnel in total will be required in 56 days (2015-01-29) to operate ETCs according to our model. The current outbreak will require massive input from the international community in order to curb the

  7. Sr-Nd isotopic characteristic, U-Pb zircon geochronology, and petrogenesis of Najmabad Granodiorite batholith, Eastern Iran

    Directory of Open Access Journals (Sweden)

    Mehrab Moradi

    2011-11-01

    Full Text Available The study area is located south of Ghonabad in Eastern Iran. This area is situated between two major faults, Darouneh to the north and Dashtbyaz to the south. The movements of these faults cased major dislocation of this block. Najmabad granodiorite to granite batholith is elongated trending east-west 2×8 Km2. Mineralization is associated with granite and monzonite. Alteration zones are: propylitic, sericitic, argillic and silicification. Chemically, granite-granodiorite is met-aluminous,, spider diagram normalized to lower continental crust show enrichment of LILE such as Rb, Cs, K and LREE (La, Ce , depletion of Ti, Sr, Ta, Nb, Ba, Cs. Based on low values of magnetic susceptibility [(5 to 11 × 10-5 SI], therefore it is classified as belonging to the ilmenite-series (reduced type. The result of U-Pb zircon age dating of granodiorite is 161.85 Ma (Middle Jurassic, Callovian time. Based on Initial εNd isotope values for granodiorite is -6.51, initial 87Sr/86Sr and 143Nd/144Nd ratios for granodiorite is (0.70913 and 0.512095, the magma for granite and granodiorite originated from the continental crust. During Middle Jurassic (Callovian due to continental collision, Upper Triassic to Lower Jurassic rocks is regionally metamorphosed. During the continental collision, Middle Jurassic (164-162Ma reduced type granitoid magma (Ilmenite series, continental crust melting formed and intruded these regional metamorphosed rock in Najmabad, Shah Kuh and Sorkh Kuh area.

  8. Nevada Test Site closure program

    International Nuclear Information System (INIS)

    Shenk, D.P.

    1994-08-01

    This report is a summary of the history, design and development, procurement, fabrication, installation and operation of the closures used as containment devices on underground nuclear tests at the Nevada Test Site. It also addresses the closure program mothball and start-up procedures. The Closure Program Document Index and equipment inventories, included as appendices, serve as location directories for future document reference and equipment use

  9. Sierra Toolkit Manual Version 4.48.

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Toolkit Team

    2018-03-01

    This report provides documentation for the SIERRA Toolkit (STK) modules. STK modules are intended to provide infrastructure that assists the development of computational engineering soft- ware such as finite-element analysis applications. STK includes modules for unstructured-mesh data structures, reading/writing mesh files, geometric proximity search, and various utilities. This document contains a chapter for each module, and each chapter contains overview descriptions and usage examples. Usage examples are primarily code listings which are generated from working test programs that are included in the STK code-base. A goal of this approach is to ensure that the usage examples will not fall out of date. This page intentionally left blank.

  10. Assessing unmet anaesthesia need in Sierra Leone: a secondary ...

    African Journals Online (AJOL)

    Department of Surgery, Connaught Hospital Freetown, Sierra Leone. 3. Department of .... need, is a key part of planning for increasing surgical capacity. Limitations. As noted by Groen et al24 this data .... Emergency and surgery services of ...

  11. Sierra Leone Journal of Biomedical Research Original Article

    African Journals Online (AJOL)

    User

    university hospital in southern Sierra Leone, a total of 66 (4.71±2.52) victims reported having been bitten by snakes in 11 ... social, economic, psychological and health impacts of snakebite ..... Epidemiological profile of snakebite cases from.

  12. Sierra Leone Journal of Biomedical Research Original Article

    African Journals Online (AJOL)

    User

    A publication of the College of Medicine and Allied Health Sciences, University of Sierra Leone ... disability associated with venomous snakebites result in lasting .... 1Mean ± Standard Error. 95% Confidence Limit. Community. Self. Reported.

  13. British Military Intervention into Sierra Leone: A Case Study

    National Research Council Canada - National Science Library

    Roberson, Walter G

    2007-01-01

    .... The successful British intervention led to the defeat of the Revolutionary United Front (RUF) and final peace accords, restored order to a failed state, and allowed the democratic restoration of the government of Sierra Leone...

  14. Population size, survival, growth, and movements of Rana sierrae

    Science.gov (United States)

    Fellers, Gary M.; Kleeman, Patrick M.; Miller, David A. W.; Halstead, Brian J.; Link, William

    2013-01-01

    Based on 2431 captures of 757 individual frogs over a 9-yr period, we found that the population of R. sierrae in one meadow–stream complex in Yosemite National Park ranged from an estimated 45 to 115 adult frogs. Rana sierrae at our relatively low elevation site (2200 m) grew at a fast rate (K = 0.73–0.78), had high overwintering survival rates (44.6–95%), lived a long time (up to 16 yr), and tended to be fairly sedentary during the summer (100% minimum convex polygon annual home ranges of 139 m2) but had low year-to-year site fidelity. Even though the amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) has been present in the population for at least 13 yr, there was no clear downward trend as might be expected from reports of R. sierrae population declines associated with Bd or from reports of widespread population decline of R. sierrae throughout its range.

  15. Sierra Leone Journal of Biomedical Research Case Study

    African Journals Online (AJOL)

    Zackary Suleiman

    A publication of the College of Medicine and Allied Health Sciences, University of Sierra Leone ... Case Study ... Peri-operative management of patients with significant cardio-respiratory disease ... contribute to patient safety by preventing any.

  16. Sierra Structural Dynamics User's Notes

    Energy Technology Data Exchange (ETDEWEB)

    Reese, Garth M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-19

    Sierra/SD provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of weapons systems. This document provides a users guide to the input for Sierra/SD. Details of input specifications for the different solution types, output options, element types and parameters are included. The appendices contain detailed examples, and instructions for running the software on parallel platforms.

  17. Sierra/SD User's Notes.

    Energy Technology Data Exchange (ETDEWEB)

    Munday, Lynn Brendon; Day, David M.; Bunting, Gregory; Miller, Scott T; Crane, Nathan K

    2018-03-01

    Sierra/SD provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of weapons systems. This document provides a users guide to the input for Sierra/SD. Details of input specifications for the different solution types, output options, element types and parameters are included. The appendices contain detailed examples, and instructions for running the software on parallel platforms.

  18. Preliminary flora of the Sierra Bacadehuachi, Sonora, Mexico

    Science.gov (United States)

    Thomas R. Van Devender; Ana Lilia Reina-Guerrero; George M. Ferguson; George Yatskievych; Beatriz E. Loyola-Reina; Gertrudis Yanes-Arvayo; Maria de la Paz Montanez-Armenta; John L. Anderson; Stephen F. Hale; Sky Jacobs

    2013-01-01

    The Sierra Bacadéhuachi in east-central Sonora is the westernmost mountain range in the Sierra Madre Occidental (SMO), located east of Bacadéhuachi, Municipio de Bacadéhuachi, 34 km east of the Chihuahua border, and 165 km south of the Arizona border. The vegetation ranges from lowland foothills thornscrub up through desert grassland to oak woodland and pine-oak forest...

  19. Use of an analog site near Raymond, California, to develop equipment and methods for characterizing a potential high-level, nuclear waste repository site at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Umari, A.M.J.; Geldon, A.; Patterson, G.; Gemmell, J.; Earle, J.; Darnell, J.

    1994-01-01

    Yucca Mountain, Nevada, currently is being investigated by the U.S. Geological Survey as a potential site for a high-level nuclear waste repository. Planned hydraulic-stress and tracer tests in fractured, tuffaceous rocks below the water table at Yucca Mountain will require work at depths in excess of 1,300 feet. To facilitate prototype testing of equipment and methods to be used in aquifer tests at Yucca Mountain, an analog site was selected in the foothills of the Sierra Nevada near Raymond, California. Two of nine 250- to 300-feet deep wells drilled into fractured, granitic rocks at the Raymond site have been instrumented with packers, pressure transducers, and other equipment that will be used at Yucca Mountain. Aquifer tests conducted at the Raymond site to date have demonstrated a need to modify some of the equipment and methods conceived for use at Yucca Mountain

  20. Nevada, the Great Recession, and Education

    Science.gov (United States)

    Verstegen, Deborah A.

    2013-01-01

    The impact of the Great Recession and its aftermath has been devastating in Nevada, especially for public education. This article discusses the budget shortfalls and the impact of the economic crisis in Nevada using case study methodology. It provides a review of documents, including Governor Gibbon's proposals for the public K-12 education system…

  1. Helping Nevada School Children Become Sun Smart

    Centers for Disease Control (CDC) Podcasts

    This podcast features Christine Thompson, Community Programs Manager at the Nevada Cancer Coalition, and author of a recent study detailing a school-based program to help Nevada school children establish healthy sun safety habits and decrease UV exposure. Christine answers questions about her research and what impact her what impact the program had on children's skin health.

  2. Nevada commercial spent nuclear fuel transportation experience

    International Nuclear Information System (INIS)

    1991-09-01

    The purpose of this report is to present an historic overview of commercial reactor spent nuclear fuel (SNF) shipments that have occurred in the state of Nevada, and to review the accident and incident experience for this type of shipments. Results show that between 1964 and 1990, 309 truck shipments covering approximately 40,000 miles moved through Nevada; this level of activity places Nevada tenth among the states in the number of truck shipments of SNF. For the same period, 15 rail shipments moving through the State covered approximately 6,500 miles, making Nevada 20th among the states in terms of number of rail shipments. None of these shipments had an accident or an incident associated with them. Because the data for Nevada are so limited, national data on SNF transportation and the safety of truck and rail transportation in general were also assessed

  3. Nevada Test Site Environmental Report 2004

    International Nuclear Information System (INIS)

    BECHTEL NEVADA

    2005-01-01

    The ''Nevada Test Site Environmental Report 2004'' was prepared by Bechtel Nevada (BN) to meet the information needs of the public and the requirements and guidelines of the U.S. Department of Energy (DOE) for annual site environmental reports. This Executive Summary presents the purpose of the document, the major programs conducted at the Nevada Test Site (NTS), NTS key environmental initiatives, radiological releases and potential doses to the public resulting from site operations, a summary of non-radiological releases, implementation status of the NTS Environmental Management System, and significant environmental accomplishments. Much of the content of this Executive Summary is also presented in a separate stand-alone pamphlet titled ''Nevada Test Site Environmental Report Summary 2004''. It was produced this year to provide a more cost-effective and wider distribution of a hardcopy summary of the ''Nevada Test Site Environmental Report 2004'' to interested DOE stakeholders

  4. Petrology, thermobarometry and geochronology of Yelapa Complex: Implications in the tectonic history of the basement of Puerto Vallarta Batholith, Mexico

    Science.gov (United States)

    Gutiérrez Aguilar, F.; Schaaf, P. E. G.; Hernandez-Trevino, T.; Solis-Pichardo, G.; Vite-Sánchez, O.

    2017-12-01

    The Yelapa Complex (YC) is localizated in the north, central and western of Cabo Corrientes in Jalisco, México. Is constituted by metasedimentary, metaigneous and migmatites which are intruded by deformed plutons. The YC are part of the Puerto Vallarta Batholith a body of 9000 km2 exposed at the mid-western part of the Mexican Pacific margin. The para-gneis of YC in the region of Chimo, present a mineral assemblage of Sil + Bt + Pl ± Grt ± Fsp ± Ilm. The orto-gneis in the región of Cabo Corrientes are constituted by Pl + Amp ± Qz ± Ap ± Zrn. Phase equilibria modelling of two paragneis yield peak conditions of 7-8 kbar and 650-700ºC. The patterns of REE of the studied rocks suggest: 1) Enrichment of LREE and flat patterns in HREE with respect to chondrite and; 2) Negative Eu anomaly in all samples analyzed suggesting plagioclase fractionation. On the other hand, the study of individual zircons using LA-ICP-MS from 3 para-gneis and 1 orto-gneis yield following information: 1) A máximum depositional age of 223 Ma, which also show abundant zircón populations with ages between 241-273 Ma for para-gneis and 2) The protolith age crystallization of 127 Ma for orto-gneis. The results along with new Sr-Nd isotopic data from whole rock and Rb-Sr in micas, suggest a tectonic evolution for the Yelapa Complex as a transition from a passive continental margin regime ( 223-273 Ma) to a continental arc setting ( 127). Thus, regional metamorphism and multiple magmatic episodes were associated to the convergence of the Farallon and North America plates during the Middle Jurassic to the Late Cretaceous.

  5. Methods and Data Used to Investigate Polonium-210 as a Source of Excess Gross-Alpha Radioactivity in Ground Water, Churchill County, Nevada

    Science.gov (United States)

    Seiler, Ralph L.

    2007-01-01

    Ground water is the major source of drinking water in the Carson River Basin, California and Nevada. Previous studies have shown that uranium and gross-alpha radioactivities in ground water can be greater than U.S. Environmental Protection Agency Maximum Contaminant Levels, particularly in the Carson Desert, Churchill County, Nevada. Studies also have shown that the primary source of the gross-alpha radioactivity and alpha-emitting radionuclides in ground water is the dissolution of uranium-rich granitic rocks and basin-fill sediments that have their origins in the Sierra Nevada. However, ground water sampled from some wells in the Carson Desert had gross-alpha radioactivities greater than could be accounted for by the decay of dissolved uranium. The occurrence of polonium-210 (Po-210) was hypothesized to explain the higher than expected gross-alpha radioactivities. This report documents and describes the study design, field and analytical methods, and data used to determine whether Po-210 is the source of excess gross-alpha radioactivity in ground water underlying the Carson Desert in and around Fallon, Nevada. Specifically, this report presents: 1) gross alpha and uranium radioactivities for 100 wells sampled from June to September 2001; and 2) pH, dissolved oxygen, specific conductance, and Po-210 radioactivity for 25 wells sampled in April and June 2007. Results of quality-control samples for the 2007 dataset are also presented.

  6. Rural migration in southern Nevada

    International Nuclear Information System (INIS)

    Mosser, D.; Soden, D.L.

    1993-01-01

    This study reviews the history of migration in two rural counties in Southern Nevada. It is part of a larger study about the impact of a proposed high-level nuclear waste repository on, in and out-migration patterns in the state. The historical record suggests a boom and bust economic cycle has predominated in the region for the past century creating conditions that should be taken into account, by decision makers, when ascertaining the long-term impacts of the proposed repository

  7. 76 FR 44535 - Revisions to the California State Implementation Plan, Northern Sierra Air Quality Management...

    Science.gov (United States)

    2011-07-26

    ... the California State Implementation Plan, Northern Sierra Air Quality Management District, Sacramento Metropolitan Air Quality Management District, and South Coast Air Quality Management District AGENCY... the Northern Sierra Air Quality Management District (NSAQMD), Sacramento Metropolitan Air Quality...

  8. 76 FR 44493 - Revisions to the California State Implementation Plan, Northern Sierra Air Quality Management...

    Science.gov (United States)

    2011-07-26

    ... California State Implementation Plan, Northern Sierra Air Quality Management District, Sacramento Metropolitan Air Quality Management District, and South Coast Air Quality Management District AGENCY... approve revisions to the Northern Sierra Air Quality Management District (NSAQMD), Sacramento Metropolitan...

  9. Atmospheric overview for the Nevada Nuclear Waste Storage Investigations, Nevada Test Site, Nye County, Nevada

    International Nuclear Information System (INIS)

    Bowen, J.L.; Egami, R.T.

    1983-11-01

    This report discusses atmospheric considerations for a nuclear waste repository at NTS. It presents the climatology of Nevada, and NTS in particular, including paleoclimatology for past climatic changes, present climatology for mean meterological conditions, feature climatological expectations, and occurrence of extreme weather. It discusses air quality aspects including an estimation of present air quality and possible dispersion conditions on NTS. It briefly assesses noise problems. It outlines a plan for an Environmental Impact Statement and covers the federal and state regulations for air quality. It identifies data for climatology and air quality and evaluates their applicability to nuclear waste repository

  10. Nevada Applied Ecology Information Center: a prototype

    International Nuclear Information System (INIS)

    Pfuderer, H.A.

    1978-01-01

    The Nevada Applied Ecology Group (NAEG) was exceptionally farsighted in establishing the Nevada Applied Ecology Information Center in January 1972, not long after the Nevada Test Site research programs began. Since its inception, the Data Base on the Environmental Aspects of the Transuranics has been proven to be a useful tool to a wide range of researchers and planners, both nationally and internationally, in addition to those associated with the NAEG. Because of its versatility and ease of access, the Data Base on the Environmental Aspects of the Transuranics has played a major role in the development of new projects by the Ecological Sciences Information Center

  11. Annotated bibliography for biologic overview for the Nevada Nuclear Waste Storage Investigations, Nevada Test Site, Nye County, Nevada

    International Nuclear Information System (INIS)

    Collins, E.; O'Farrell, T.P.; Rhoads, W.A.

    1981-12-01

    This annotated bibliography was compiled to accompany the Biologic Overview for the Nevada Nuclear Waste Storage Investigations, Nevada Test Site, Nye County, Nevada, EG and G, Santa Barbara Operations Report No. EGG 1183-2443, which documents and synthesizes important biotic information related to Nevada Nuclear Waste Storage Investigations (NNWSI). As such, it is an important part of the NNWSI screening process that was designed to include a systematic, traceable, defensible, and documented basis for a decision to proceed or not with site-specific phases on NTS. Included are all published, and available but unpublished, baseline information on life histories, habitat requirements, distributions, and ecological relationships of the flora and fauna of the region. Special effort was made to include information on endangered, threatened, or sensitive species. 131 references

  12. Spatial Patterns between Regolith Thickness and Forest Productivity in the Southern Sierra CZO

    Science.gov (United States)

    Ferrell, R. M.; Ferrell, D. F.; Hartsough, P. C.; O'Geen, T. T.

    2015-12-01

    Soil in conjunction with underlying weathered bedrock make up what is referred to as regolith, which can be thought of as the substrate that actively contributes water and nutrients to above ground biomass. As a result, regolith thickness is an important regulating factor of forest health and drought tolerance in the Sierra Nevada. Our project examined the relationships between landscape position, regolith thickness, and tree productivity within a sub watershed of the Southern Sierra Critical Zone Observatory. We hypothesized that tree productivity will increase with increasing regolith thickness. Data was collected in the summer of 2015 at sixty-five sites within a 522-ha watershed averaging 1180m in elevation with a MAP of 80cm and a MAT of 11C. Sites were randomly selected from a grid and then stratified in the field to capture representative samples from different landscape positions. Regolith was sampled using a hand auger with attachable extensions. At each site we augered to hard bedrock or a maximum depth of 7.56 m, which ever was shallower. Biomass measurements were made for all conifer species (DBH>20cm) within a 10m radius of the primary auger hole. Tree age was measured from a representative tree for all species in the plots. Preliminary findings suggest that there is a weak correlation between landscape position/slope and regolith thickness, likely due to differences in lithology. It also appears that terrain shape can result in conflicting outcomes: 1. It can focus water to promote physical and chemical weathering and thick regolith; or, 2. water focusing can result in landscape scouring, removing soil and weathered bedrock to create shallow regolith. Productivity appears to be a function of regolith thickness, effective precipitation and landscape position. Water collecting areas in the lower watershed are shallow to bedrock, but typically receive high amounts of effective precipitation resulting in greater tree productivity. Moreover, thick regolith

  13. Environmental values and risk: A review of Sierra Club policies

    International Nuclear Information System (INIS)

    Craig, P.P.

    1999-01-01

    Sierra Club values are driven by an overriding environmental ethic. Sierra Club environmental values may be characterized by the concept of 'usufruct' a term favored by United States Founding Father Thomas Jefferson. Usufruct conveys the idea that the environment is ours to use, but not to destroy. Each generation has the obligation to pass on to future generations a world at least as environmentally rich as the one it inherited. It is appropriate to accept risk today in order to preserve the environment for generations yet to come. As viewed through the lens of its formal policies, the Sierra Club is an organization that embraces technology, but insists that technology be evaluated comprehensively, taking full account of both environmental and social externalities. The Club is 'risk averse' with respect to early introduction of technologies seen as likely to have significant negative environmental or social impact. The Club places heavy emphasis on process, which must involve the public meaningfully

  14. SIERRA - A 3-D device simulator for reliability modeling

    Science.gov (United States)

    Chern, Jue-Hsien; Arledge, Lawrence A., Jr.; Yang, Ping; Maeda, John T.

    1989-05-01

    SIERRA is a three-dimensional general-purpose semiconductor-device simulation program which serves as a foundation for investigating integrated-circuit (IC) device and reliability issues. This program solves the Poisson and continuity equations in silicon under dc, transient, and small-signal conditions. Executing on a vector/parallel minisupercomputer, SIERRA utilizes a matrix solver which uses an incomplete LU (ILU) preconditioned conjugate gradient square (CGS, BCG) method. The ILU-CGS method provides a good compromise between memory size and convergence rate. The authors have observed a 5x to 7x speedup over standard direct methods in simulations of transient problems containing highly coupled Poisson and continuity equations such as those found in reliability-oriented simulations. The application of SIERRA to parasitic CMOS latchup and dynamic random-access memory single-event-upset studies is described.

  15. Ebola Surveillance - Guinea, Liberia, and Sierra Leone.

    Science.gov (United States)

    McNamara, Lucy A; Schafer, Ilana J; Nolen, Leisha D; Gorina, Yelena; Redd, John T; Lo, Terrence; Ervin, Elizabeth; Henao, Olga; Dahl, Benjamin A; Morgan, Oliver; Hersey, Sara; Knust, Barbara

    2016-07-08

    Developing a surveillance system during a public health emergency is always challenging but is especially so in countries with limited public health infrastructure. Surveillance for Ebola virus disease (Ebola) in the West African countries heavily affected by Ebola (Guinea, Liberia, and Sierra Leone) faced numerous impediments, including insufficient numbers of trained staff, community reticence to report cases and contacts, limited information technology resources, limited telephone and Internet service, and overwhelming numbers of infected persons. Through the work of CDC and numerous partners, including the countries' ministries of health, the World Health Organization, and other government and nongovernment organizations, functional Ebola surveillance was established and maintained in these countries. CDC staff were heavily involved in implementing case-based surveillance systems, sustaining case surveillance and contact tracing, and interpreting surveillance data. In addition to helping the ministries of health and other partners understand and manage the epidemic, CDC's activities strengthened epidemiologic and data management capacity to improve routine surveillance in the countries affected, even after the Ebola epidemic ended, and enhanced local capacity to respond quickly to future public health emergencies. However, the many obstacles overcome during development of these Ebola surveillance systems highlight the need to have strong public health, surveillance, and information technology infrastructure in place before a public health emergency occurs. Intense, long-term focus on strengthening public health surveillance systems in developing countries, as described in the Global Health Security Agenda, is needed.The activities summarized in this report would not have been possible without collaboration with many U.S and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html).

  16. Nevada Isostatic Residual Gravity Over Basement

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study of gravity data from Nevada is part of a statewide analysis of mineral resources. The main objective of the gravity study were: 1) to infer the structure...

  17. Gravity Data for the State of Nevada

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gravity data for the entire state of Nevada and adjacent parts of California, Utah, and Arizona are presented. About 80,000 gravity stations were compiled primarily...

  18. Nevada Test Site Environmental Report 2003

    Energy Technology Data Exchange (ETDEWEB)

    Bechtel Nevada

    2004-10-01

    The Nevada Test Site Environmental Report 2003 was prepared by Bechtel Nevada to meet the requirements and guidelines of the U.S. Department of Energy and the information needs of the public. This report is meant to be useful to members of the public, public officials, regulators, and Nevada Test Site contractors. The Executive Summary strives to present in a concise format the purpose of the document, the NTS mission and major programs, a summary of radiological releases and doses to the public resulting from site operations, a summary of non-radiological releases, and an overview of the Nevada Test Site Environmental Management System. The Executive Summary, combined with the following Compliance Summary, are written to meet all the objectives of the report and to be stand-alone sections for those who choose not to read the entire document.

  19. Nevada National Security Site Environmental Report 2013

    Energy Technology Data Exchange (ETDEWEB)

    Wills, C.

    2014-09-09

    This report was prepared to meet the information needs of the public and the requirements and guidelines of the U.S. Department of Energy (DOE) for annual site environmental reports. It was prepared by National Security Technologies, LLC (NSTec), for the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office (NNSA/NFO) (formerly designated as the Nevada Site Office [NNSA/NSO]). The new field office designation occurred in March 2013. Published reports cited in this 2013 report, therefore, may bear the name or authorship of NNSA/NSO. This and previous years’ reports, called Annual Site Environmental Reports (ASERs), Nevada Test Site Environmental Reports (NTSERs), and, beginning in 2010, Nevada National Security Site Environmental Reports (NNSSERs), are posted on the NNSA/NFO website at http://www.nv.energy.gov/library/publications/aser.aspx.

  20. Sierra/Aria 4.48 Verification Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Thermal Fluid Development Team

    2018-04-01

    Presented in this document is a portion of the tests that exist in the Sierra Thermal/Fluids verification test suite. Each of these tests is run nightly with the Sierra/TF code suite and the results of the test checked under mesh refinement against the correct analytic result. For each of the tests presented in this document the test setup, derivation of the analytic solution, and comparison of the code results to the analytic solution is provided. This document can be used to confirm that a given code capability is verified or referenced as a compilation of example problems.

  1. Swimming Upstream: Tobacco Policy Making in Nevada

    OpenAIRE

    Tung, Gregory MPH; Glantz, Stanton A. Ph.D.

    2008-01-01

    The tobacco industry is a major political force in Nevada. The industry dominated state politics through a combination of strategic alliances with the hospitality and gaming industries and campaign contributions. From 1990-2006 the tobacco industry contributed $552,111 to the state political parties and individuals running for state office. In 1975, health groups in Nevada attempted to pass a legislative proposal, AB 17, that would have required smoking and non-smoking sections in al...

  2. Comparison of preliminary herpetofaunas of the Sierras la Madera (Oposura) and Bacadehuachi with the mainland Sierra Madre Occidental in Sonora, Mexico

    Science.gov (United States)

    Thomas R. Van Devender; Erik F. Enderson; Dale S. Turner; Roberto A. Villa; Stephen F. Hale; George M. Ferguson; Charles. Hedgcock

    2013-01-01

    Amphibians and reptiles were observed in the Sierra La Madera (59 species), an isolated Sky Island mountain range, and the Sierra Bacadéhuachi (30 species), the westernmost mountain range in the Sierra Madre Occidental (SMO) range in east-central Sonora. These preliminary herpetofaunas were compared with the herpetofauna of the Yécora area in eastern Sonora in the main...

  3. Comparison of the tropical floras of the Sierra la Madera and the Sierra Madre Occidental, Sonora, Mexico

    Science.gov (United States)

    Thomas R. Van Devender; Gertrudis Yanes-Arvayo; Ana Lilia Reina-Guerrero; Melissa Valenzuela-Yanez; Maria de la Paz Montanez-Armenta; Hugo Silva-Kurumiya

    2013-01-01

    The floras of the tropical vegetation in the Sky Island Sierra la Madera (SMA) near Moctezuma in northeastern Sonora (30°00’N 109°18’W) and the Yécora (YEC) area in the Sierra Madre Occidental (SMO) in eastern Sonora (28°25’N 109°15”W) were compared. The areas are 175 km apart. Tropical vegetation includes foothills thornscrub (FTS) in both areas and tropical deciduous...

  4. Sierra/Solid Mechanics 4.48 User's Guide.

    Energy Technology Data Exchange (ETDEWEB)

    Merewether, Mark Thomas; Crane, Nathan K; de Frias, Gabriel Jose; Le, San; Littlewood, David John; Mosby, Matthew David; Pierson, Kendall H.; Porter, Vicki L.; Shelton, Timothy; Thomas, Jesse David; Tupek, Michael R.; Veilleux, Michael; Gampert, Scott; Xavier, Patrick G.; Plews, Julia A.

    2018-03-01

    Sierra/SolidMechanics (Sierra/SM) is a Lagrangian, three-dimensional code for finite element analysis of solids and structures. It provides capabilities for explicit dynamic, implicit quasistatic and dynamic analyses. The explicit dynamics capabilities allow for the efficient and robust solution of models with extensive contact subjected to large, suddenly applied loads. For implicit problems, Sierra/SM uses a multi-level iterative solver, which enables it to effectively solve problems with large deformations, nonlinear material behavior, and contact. Sierra/SM has a versatile library of continuum and structural elements, and a large library of material models. The code is written for parallel computing environments enabling scalable solutions of extremely large problems for both implicit and explicit analyses. It is built on the SIERRA Framework, which facilitates coupling with other SIERRA mechanics codes. This document describes the functionality and input syntax for Sierra/SM.

  5. Sierra/solid mechanics 4.22 user's guide.

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Jesse David

    2011-10-01

    Sierra/SolidMechanics (Sierra/SM) is a Lagrangian, three-dimensional code for the analysis of solids and structures. It provides capabilities for explicit dynamic and implicit quasistatic and dynamic analyses. The explicit dynamics capabilities allow for the efficient and robust solution of models subjected to large, suddenly applied loads. For implicit problems, Sierra/SM uses a multi-level iterative solver, which enables it to effectively solve problems with large deformations, nonlinear material behavior, and contact. Sierra/SM has a versatile library of continuum and structural elements, and an extensive library of material models. The code is written for parallel computing environments, and it allows for scalable solutions of very large problems for both implicit and explicit analyses. It is built on the SIERRA Framework, which allows for coupling with other SIERRA mechanics codes. This document describes the functionality and input structure for Sierra/SM.

  6. Threatened plant species of the Nevada Test Site, Ash Meadows, central-southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Beatley, J.C.

    1977-04-01

    This report is a companion one to Endangered Plant Species of the Nevada Test Site, Ash Meadows, and Central-Southern Nevada (COO-2307-11) and deals with the threatened plant species of the same area. The species are those cited in the Federal Register, July 1, 1975, and include certain ones listed as occurring only in California or Arizona, but which occur also in central-southern Nevada. As with the earlier report, the purpose of this one is to record in detail the location of the past plant collections which constitute the sole or principal basis for defining the species' distributions and frequency of occurrence in southern Nye County, Nevada, and to recommend the area of the critical habitat where this is appropriate. Many of the species occur also in southern California, and for these the central-southern Nevada records are presented for consideration of the overall status of the species throughout its range.

  7. EnergyFit Nevada (formerly known as the Nevada Retrofit Initiative) final report and technical evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Carvill, Anna; Bushman, Kate; Ellsworth, Amy

    2014-06-17

    The EnergyFit Nevada (EFN) Better Buildings Neighborhood Program (BBNP, and referred to in this document as the EFN program) currently encourages Nevada residents to make whole-house energy-efficient improvements by providing rebates, financing, and access to a network of qualified home improvement contractors. The BBNP funding, consisting of 34 Energy Efficiency Conservation Block Grants (EECBG) and seven State Energy Program (SEP) grants, was awarded for a three-year period to the State of Nevada in 2010 and used for initial program design and implementation. By the end of first quarter in 2014, the program had achieved upgrades in 553 homes, with an average energy reduction of 32% per home. Other achievements included: Completed 893 residential energy audits and installed upgrades in 0.05% of all Nevada single-family homes1 Achieved an overall conversation rate of 38.1%2 7,089,089 kWh of modeled energy savings3 Total annual homeowner energy savings of approximately $525,7523 Efficiency upgrades completed on 1,100,484 square feet of homes3 $139,992 granted in loans to homeowners for energy-efficiency upgrades 29,285 hours of labor and $3,864,272 worth of work conducted by Nevada auditors and contractors4 40 contractors trained in Nevada 37 contractors with Building Performance Institute (BPI) certification in Nevada 19 contractors actively participating in the EFN program in Nevada 1 Calculated using 2012 U.S. Census data reporting 1,182,870 homes in Nevada. 2 Conversion rate through March 31, 2014, for all Nevada Retrofit Initiative (NRI)-funded projects, calculated using the EFN tracking database. 3 OptiMiser energy modeling, based on current utility rates. 4 This is the sum of $3,596,561 in retrofit invoice value and $247,711 in audit invoice value.

  8. Peruvian Rural School Construction System. SERP 71: Sierra Type.

    Science.gov (United States)

    Cangiano, Miguel

    Based on cooperative action of the government and local communities, the Peruvian Rural School System (SERP 71) evolved from the necessity to reconstruct Peruvian schools of the Sierra region after the earthquake of 1970, and from Peru's new educational reform law (1970) which called for an active-dynamic pupil attitude, continuous updating of…

  9. Indigenous knowledge in cattle breeding in Sierra Leone | Abdul ...

    African Journals Online (AJOL)

    This study was conducted in order to document and preserve valuable indigenous knowledge in cattle breeding and production under traditional cattle production system in Sierra Leone. Data were collected from thirty (30) cattle farms from three locations: Gbindi (16 farms), Sackelereh (7 farms), and Flamansa (7 farms) in ...

  10. Sierra Leone Journal of Biomedical Research Original Article

    African Journals Online (AJOL)

    User

    A publication of the College of Medicine and Allied Health Sciences, University of Sierra ... TESTING (VCT) FOR HIV AMONG NURSING STUDENTS IN ZAMBIA ... All students were aware of where to go for VCT, and 80% .... attitudes that assure patients that they will be .... them better practitioners, but their awareness of.

  11. Young Women's Political Participation in Post-War Sierra Leone ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The end of the civil war in Sierra Leone in 2002 was facilitated in many ways by women through women's pro-democracy movements. These movements will continue to be pivotal in the gradual strengthening of democratic governance structures. Irrespective of the immense barriers that they face, women of all ages have ...

  12. Geology of Sierra de San Miguel area Rocha department (Uruguay)

    International Nuclear Information System (INIS)

    Muzio, R.; Veroslavsky, G.; Morales, E. . E mail: rossana@fcien.edu.uy

    2004-01-01

    This paper is part of a regional study about Mesozoic magmatism, tectonics and sedimentation in Uruguay. As a result of the geological studies carried out in Sierra de San Miguel area (Rocha department), lithological descriptions, their stratigraphic relationships and their petrographic characterization are presented [es

  13. Ecosystems and diversity of the Sierra Madre Occidental

    Science.gov (United States)

    M. S. Gonzalez-Elizondo; M. Gonzalez-Elizondo; L. Ruacho Gonzalez; I. L. Lopez Enriquez; F. I . Retana Renteria; J. A. Tena Flores

    2013-01-01

    The Sierra Madre Occidental (SMO) is the largest continuous ignimbrite plate on Earth. Despite its high biological and cultural diversity and enormous environmental and economical importance, it is yet not well known. We describe the vegetation and present a preliminary regionalization based on physiographic, climatic, and floristic criteria. A confluence of three main...

  14. Diets of California spotted owls in the Sierra National Forest

    Science.gov (United States)

    Thomas E. Munton; Kenneth D. Johnson; George N. Steger; Gary P. Eberlein

    2002-01-01

    From May 1987 through October 1992 and from July through August 1998, we studied diets of California spotted owls (Strix occidentalis occidentalis). Regurgitated pellets were collected at roost and nest sites between 1,000 and 7,600 ft elevation in the Sierra National Forest and were examined for remnant bones, feathers, and insect exoskeletons....

  15. Sierra Leone Journal of Biomedical Research Original Article

    African Journals Online (AJOL)

    User

    recommendations to the health sector of Sierra Leone for it prevention. This retrospective .... pressure. 27% of the population is exposed to 3 to. 5 of these risk factors. According to .... Many studies have identified foot ulcer as the most common ...

  16. Military Interventions in Sierra Leone: Lessons from a Failed State

    National Research Council Canada - National Science Library

    Woods, Larry J; Reese, Timothy R

    2008-01-01

    This study by Larry J. Woods and Colonel Timothy R. Reese analyzes the massive turmoil afflicting the nation of Sierra Leone, 1993-2002, and the efforts by a variety of outside forces to bring lasting stability to that small country...

  17. Biologic overview for the Nevada Nuclear Waste Storage Investigations, Nevada Test Site, Nye County, Nevada

    International Nuclear Information System (INIS)

    Collins, E.; O'Farrell, T.P.; Rhoads, W.A.

    1982-01-01

    The Nevada Nuclear Waste Storage Investigations project study area includes five major vegetation associations characteristic of the transition between the northern extent of the Mojave Desert and the southern extent of the Great Basin Desert. A total of 32 species of reptiles, 66 species of birds, and 46 species of mammals are known to occur within these associations elsewhere on the Nevada Test Site. Ten species of plants, and the mule deer, wild horse, feral burro, and desert tortoise were defined as possible sensitive species because they are protected by federal and state regulations, or are being considered for such protection. The major agricultural resources of southern Nye County included 737,000 acres of public grazing land managed by the Bureau of Land Management, and 9500 acres of irrigated crop land located in the Beatty/Oasis valleys, the Amargosa Valley, and Ash Meadows. Range lands are of poor quality. Alfalfa and cotton are the major crops along with small amounts of grains, Sudan grass, turf, fruits, and melons. The largest impacts to known ecosystems are expected to result from: extensive disturbances associated with construction of roads, seismic lines, drilling pads, and surface facilities; storage and leaching of mined spoils; disposal of water; off-road vehicle travel; and, over several hundred years, elevated soil temperatures. Significant impacts to off-site areas such as Ash Meadows are anticipated if new residential developments are built there to accommodate an increased work force. Several species of concern and their essential habitats are located at Ash Meadows. Available literature contained sufficient baseline information to assess potential impacts of the proposed project on an area-wide basis. It was inadequate to support analysis of potential impacts on specific locations selected for site characterization studies, mining an exploratory shaft, or the siting and operation of a repository

  18. Nevada Test Site Resource Management Plan: Annual summary, January 2000

    International Nuclear Information System (INIS)

    2000-01-01

    The Nevada Test Site Resource Management Plan published in December of 1998 (DOE/NV--518) describes the Nevada Test Site stewardship mission and how its accomplishment will preserve the resources of the ecoregion while accomplishing the objectives of the mission. As part of the Nevada Test Site Resource Management Plan, DOE Nevada Operations Office has committed to perform and publish an annual summary review of DOE Nevada Operations' stewardship of the Nevada Test Site. This annual summary includes a description of progress made toward the goals of the Nevada Test Site Resource Management Plan, pertinent monitoring data, actions that were taken to adapt to changing conditions, and any other changes to the Nevada Test Site Resource Management Plan

  19. Nevada Test Site Resource Management Plan: Annual summary, January 2000

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-01-01

    The Nevada Test Site Resource Management Plan published in December of 1998 (DOE/NV--518) describes the Nevada Test Site stewardship mission and how its accomplishment will preserve the resources of the ecoregion while accomplishing the objectives of the mission. As part of the Nevada Test Site Resource Management Plan, DOE Nevada Operations Office has committed to perform and publish an annual summary review of DOE Nevada Operations' stewardship of the Nevada Test Site. This annual summary includes a description of progress made toward the goals of the Nevada Test Site Resource Management Plan, pertinent monitoring data, actions that were taken to adapt to changing conditions, and any other changes to the Nevada Test Site Resource Management Plan.

  20. Climate Resiliency Planning: Making Extreme Event Science Useful for Managers and Planners in Northern Nevada

    Science.gov (United States)

    McCarthy, M.; Kenneston, A.; Wall, T. U.; Brown, T. J.; Redmond, K. T.

    2014-12-01

    Effective climate resiliency planning at the regional level requires extensive interactive dialogue among climate scientists, emergency managers, public health officials, urban planners, social scientists, and policy makers. Engaging federal, tribal, state, local governments and private sector business and infrastructure owners/operators in defining, assessing and characterizing the impacts of extreme events allows communities to understand how different events "break the system" forcing local communities to seek support and resources from state/federal governments and/or the private sector and what actions can be taken proactively to mitigate consequences and accelerate recovery. The Washoe County Regional Resiliency Study was prepared in response to potential climate variability related impacts specific to the Northern Nevada Region. The last several decades have seen dramatic growth in the region, coupled with increased resource demands that have forced local governments to consider how those impacts will affect the region and may, in turn, impact the region's ability to provide essential services. The Western Regional Climate Center of the Desert Research Institute provided a synthesis of climate studies with predictions regarding plausible changes in the local climate of Northern California and Nevada for the next 50 years. In general, these predictions indicate that the region's climate is undergoing a gradual shift, which will primarily affect the frequency, amount, and form of precipitation in the Sierra Nevada and Great Basin. Changes in water availability and other extreme events may have serious and long lasting effects in the Northern Nevada Region, and create a variety of social, environmental and economic concerns. A range of extreme events were considered including Adverse Air Quality, Droughts, Floods, Heat Waves, High Wind, Structure Fires, Wildland Fires, and Major Winter Storms. Due to the complexity of our climate systems, and the difficulty in

  1. Health complications of female genital mutilation in Sierra Leone

    Directory of Open Access Journals (Sweden)

    Bjälkander O

    2012-07-01

    Full Text Available Owolabi Bjälkander,1 Laurel Bangura,2 Bailah Leigh,3 Vanja Berggren,1 Staffan Bergström,1 Lars Almroth11Division of Global Health, Department of Public Health, Karolinska Institutet, Stockholm, Sweden; 2Inter Africa Committee, Sierra Leone; 3Department of Community Health, College of Medicine and Allied Health Sciences, University of Sierra Leone, Sierra LeoneAbstract: Sierra Leone has one of the highest rates of female genital mutilation (FGM in the world, and yet little is known about the health consequences of the practice.Purpose: To explore whether and what kind of FGM-related health complications girls and women in Sierra Leone experience, and to elucidate their health care-seeking behaviors.Patients and methods: A feasibility study was conducted to test and refine questionnaires and methods used for this study. Thereafter, a cross-section of girls and women (n = 258 attending antenatal care and Well Women Clinics in Bo Town, Bo District, in the southern region and in Makeni Town, Bombali District, in the northern region of Sierra Leone were randomly selected. Participants answered interview-administrated pretested structured questionnaires with open-ended-questions, administrated by trained female personnel.Results: All respondents had undergone FGM, most between 10 and 14 years of age. Complications were reported by 218 respondents (84.5%, the most common ones being excessive bleeding, delay in or incomplete healing, and tenderness. Fever was significantly more often reported by girls who had undergone FGM before 10 years of age compared with those who had undergone the procedure later. Out of those who reported complications, 187 (85.8% sought treatment, with 89 of them visiting a traditional healer, 75 a Sowei (traditional circumciser, and 16 a health professional.Conclusion: The high prevalence rate of FGM and the proportion of medical complications show that FGM is a matter for public health concern in Sierra Leone. Girls who

  2. Lassa fever in post-conflict sierra leone.

    Directory of Open Access Journals (Sweden)

    Jeffrey G Shaffer

    2014-03-01

    Full Text Available Lassa fever (LF, an often-fatal hemorrhagic disease caused by Lassa virus (LASV, is a major public health threat in West Africa. When the violent civil conflict in Sierra Leone (1991 to 2002 ended, an international consortium assisted in restoration of the LF program at Kenema Government Hospital (KGH in an area with the world's highest incidence of the disease.Clinical and laboratory records of patients presenting to the KGH Lassa Ward in the post-conflict period were organized electronically. Recombinant antigen-based LF immunoassays were used to assess LASV antigenemia and LASV-specific antibodies in patients who met criteria for suspected LF. KGH has been reestablished as a center for LF treatment and research, with over 500 suspected cases now presenting yearly. Higher case fatality rates (CFRs in LF patients were observed compared to studies conducted prior to the civil conflict. Different criteria for defining LF stages and differences in sensitivity of assays likely account for these differences. The highest incidence of LF in Sierra Leone was observed during the dry season. LF cases were observed in ten of Sierra Leone's thirteen districts, with numerous cases from outside the traditional endemic zone. Deaths in patients presenting with LASV antigenemia were skewed towards individuals less than 29 years of age. Women self-reporting as pregnant were significantly overrepresented among LASV antigenemic patients. The CFR of ribavirin-treated patients presenting early in acute infection was lower than in untreated subjects.Lassa fever remains a major public health threat in Sierra Leone. Outreach activities should expand because LF may be more widespread in Sierra Leone than previously recognized. Enhanced case finding to ensure rapid diagnosis and treatment is imperative to reduce mortality. Even with ribavirin treatment, there was a high rate of fatalities underscoring the need to develop more effective and/or supplemental treatments for

  3. Environmental Survey preliminary report, Nevada Test Site, Mercury, Nevada

    International Nuclear Information System (INIS)

    1988-04-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Nevada Test Site (NTS), conducted June 22 through July 10, 1987. The Survey is being conducted by a multidisciplinary team of environmental specialists led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team members are outside experts being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the NTS. The Survey covers all environment media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations and activities performed at the NTS, and interviews with site personnel. The Survey team developed a Sampling and Analysis Plan to assist in further assessing certain environmental problems identified during its on-site activities. The Sampling and Analysis Plan is being executed by the Battelle Columbus Division under contract with DOE. When completed, the results will be incorporated into the NTS Environmental Survey Interim Report. The Interim Report will reflect the final determinations of the NTS Survey. 165 refs., 42 figs., 52 tabs

  4. Environmental Survey preliminary report, Nevada Test Site, Mercury, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    1988-04-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Nevada Test Site (NTS), conducted June 22 through July 10, 1987. The Survey is being conducted by a multidisciplinary team of environmental specialists led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team members are outside experts being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the NTS. The Survey covers all environment media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations and activities performed at the NTS, and interviews with site personnel. The Survey team developed a Sampling and Analysis Plan to assist in further assessing certain environmental problems identified during its on-site activities. The Sampling and Analysis Plan is being executed by the Battelle Columbus Division under contract with DOE. When completed, the results will be incorporated into the NTS Environmental Survey Interim Report. The Interim Report will reflect the final determinations of the NTS Survey. 165 refs., 42 figs., 52 tabs.

  5. Concentrating Solar Power Projects - Nevada Solar One | Concentrating Solar

    Science.gov (United States)

    Power | NREL Nevada Solar One This page provides information on Nevada Solar One, a concentrating solar power (CSP) project, with data organized by background, participants, and power plant configuration. Acciona Energy's Nevada Solar One is the third largest CSP plant in the world and the first plant

  6. 40 CFR 52.1477 - Nevada air pollution emergency plan.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Nevada air pollution emergency plan. 52.1477 Section 52.1477 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Nevada § 52.1477 Nevada air pollution emergency plan. Section 6.1.5 of...

  7. Ecosystem stressors in southern Nevada [Chapter 2] (Executive Summary)

    Science.gov (United States)

    Burton K. Pendleton; Jeanne C. Chambers; Matthew L. Brooks; Steven M. Ostoja

    2013-01-01

    Southern Nevada ecosystems are subject to a number of stressors that range in scope from local to regional to global. At the regional scale, human population growth and related activities constitute a major stressor. Nevada has undergone significant change due to unprecedented population growth and ongoing global change processes. Nevada’s growth rate has been the...

  8. Compilation of modal analyses of volcanic rocks from the Nevada Test Site area, Nye County, Nevada

    International Nuclear Information System (INIS)

    Page, W.R.

    1990-01-01

    Volcanic rock samples collected from the Nevada Test Site, Nye County, Nevada, between 1960 and 1985 were analyzed by thin section to obtain petrographic mode data. In order to provide rapid accessibility to the entire database, all data from the cards were entered into a computerized database. This computer format will enable workers involved in stratigraphic studies in the Nevada Test Site area and other locations in southern Nevada to perform independent analyses of the data. The data were compiled from the mode cards into two separate computer files. The first file consists of data collected from core samples taken from drill holes in the Yucca Mountain area. The second group of samples were collected from measured sections and surface mapping traverses in the Nevada Test Site area. Each data file is composed of computer printouts of tables with mode data from thin section point counts, comments on additional data, and location data. Tremendous care was taken in transferring the data from the cards to computer, in order to preserve the original information and interpretations provided by the analyzer. In addition to the data files above, a file is included that consists of Nevada Test Site petrographic data published in other US Geological Survey and Los Alamos National Laboratory reports. These data are presented to supply the user with an essentially complete modal database of samples from the volcanic stratigraphic section in the Nevada Test Site area. 18 refs., 4 figs

  9. United States Geological Survey, programs in Nevada

    Science.gov (United States)

    ,

    1995-01-01

    The U.S. Geological Survey (USGS) has been collecting and interpreting natural-resources data in Nevada for more than 100 years. This long-term commitment enables planners to manage better the resources of a State noted for paradoxes. Although Nevada is one of the most sparsely populated States in the Nation, it has the fastest growing population (fig. 1). Although 90 percent of the land is rural, it is the fourth most urban State. Nevada is the most arid State and relies heavily on water resources. Historically, mining and agriculture have formed the basis of the economy; now tourism and urban development also have become important. The USGS works with more than 40 local, State, and other Federal agencies in Nevada to provide natural-resources information for immediate and long-term decisions.Subjects included in this fact sheet:Low-Level Radioactive-Waste DisposalMining and Water in the Humboldt BasinAquifer Systems in the Great BasinWater Allocation in Truckee and Carson BasinsNational Water-Quality Assessment ProgramMinerals Assessment for Land ManagementIrrigation DrainageGround-Water Movement at Nevada Test SiteOil and Gas ResourcesNational Mapping ProgramDigital Mapping and Aerial PhotographyCollection of Hydrologlc DataGeologic MappingEarthquake HazardsAssessing Mineral Resources of the SubsurfaceEarth Observation DataCooperative Programs

  10. Nevada Test Site Environmental Report 2004

    Energy Technology Data Exchange (ETDEWEB)

    BECHTEL NEVADA

    2005-10-01

    The ''Nevada Test Site Environmental Report 2004'' was prepared by Bechtel Nevada (BN) to meet the information needs of the public and the requirements and guidelines of the U.S. Department of Energy (DOE) for annual site environmental reports. This Executive Summary presents the purpose of the document, the major programs conducted at the Nevada Test Site (NTS), NTS key environmental initiatives, radiological releases and potential doses to the public resulting from site operations, a summary of non-radiological releases, implementation status of the NTS Environmental Management System, and significant environmental accomplishments. Much of the content of this Executive Summary is also presented in a separate stand-alone pamphlet titled ''Nevada Test Site Environmental Report Summary 2004''. It was produced this year to provide a more cost-effective and wider distribution of a hardcopy summary of the ''Nevada Test Site Environmental Report 2004'' to interested DOE stakeholders.

  11. The link between volcanism and plutonism in epizonal magma systems; high-precision U–Pb zircon geochronology from the Organ Mountains caldera and batholith, New Mexico

    Science.gov (United States)

    Rioux, Matthew; Farmer, Lang; Bowring, Samuel; Wooton, Kathleen M.; Amato, Jeffrey M.; Coleman, Drew S.; Verplanck, Philip L.

    2016-01-01

    The Organ Mountains caldera and batholith expose the volcanic and epizonal plutonic record of an Eocene caldera complex. The caldera and batholith are well exposed, and extensive previous mapping and geochemical analyses have suggested a clear link between the volcanic and plutonic sections, making this an ideal location to study magmatic processes associated with caldera volcanism. Here we present high-precision thermal ionization mass spectrometry U–Pb zircon dates from throughout the caldera and batholith, and use these dates to test and improve existing petrogenetic models. The new dates indicate that Eocene volcanic and plutonic rocks in the Organ Mountains formed from ~44 to 34 Ma. The three largest caldera-related tuff units yielded weighted mean 206Pb/238U dates of 36.441 ± 0.020 Ma (Cueva Tuff), 36.259 ± 0.016 Ma (Achenback Park tuff), and 36.215 ± 0.016 Ma (Squaw Mountain tuff). An alkali feldspar granite, which is chemically similar to the erupted tuffs, yielded a synchronous weighted mean 206Pb/238U date of 36.259 ± 0.021 Ma. Weighted mean 206Pb/238U dates from the larger volume syenitic phase of the underlying Organ Needle pluton range from 36.130 ± 0.031 to 36.071 ± 0.012 Ma, and the youngest sample is 144 ± 20 to 188 ± 20 ka younger than the Squaw Mountain and Achenback Park tuffs, respectively. Younger plutonism in the batholith continued through at least 34.051 ± 0.029 Ma. We propose that the Achenback Park tuff, Squaw Mountain tuff, alkali feldspar granite and Organ Needle pluton formed from a single, long-lived magma chamber/mush zone. Early silicic magmas generated by partial melting of the lower crust rose to form an epizonal magma chamber. Underplating of the resulting mush zone led to partial melting and generation of a high-silica alkali feldspar granite cap, which erupted to form the tuffs. The deeper parts of the chamber underwent continued recharge and crystallization for 144 ± 20 ka after the

  12. The Southern Nevada Agency Partnership Science and Research Synthesis: Science to support land management in Southern Nevada

    Science.gov (United States)

    Jeanne C. Chambers; Matthew L. Brooks; Burton K. Pendleton; Carol B. Raish

    2013-01-01

    This synthesis provides information related to the Southern Nevada Agency Partnership (SNAP) Science and Research Strategy Goal 1 - to restore, sustain and enhance southern Nevada’s ecosystems - and Goal 2 - to provide for responsible use of southern Nevada’s lands in a manner that preserves heritage resources and promotes an understanding of human interaction with the...

  13. The Southern Nevada Agency Partnership Science and Research Synthesis: Science to support land management in Southern Nevada - Executive Summary

    Science.gov (United States)

    Jeanne C. Chambers; Matthew L. Brooks; Burton K. Pendleton; Carol B. Raish

    2013-01-01

    This synthesis provides information related to the Southern Nevada Agency Partnership (SNAP) Science and Research Strategy Goal 1 - to restore, sustain and enhance southern Nevada’s ecosystems - and Goal 2 - to provide for responsible use of southern Nevada’s lands in a manner that preserves heritage resources and promotes an understanding of human interaction with the...

  14. Nevada Test Site Wetlands Assessment

    Energy Technology Data Exchange (ETDEWEB)

    D. J. Hansen

    1997-05-01

    This report identifies 16 Nevada Test Site (NTS) natural water sources that may be classified by the U.S. Army Corps of Engineers (USACE) as jurisdictional wetlands and identifies eight water sources that may be classified as waters of the United States. These water sources are rare, localized habitats on the NTS that are important to regional wildlife and to isolated populations of water tolerant plants and aquatic organisms. No field investigations on the NTS have been conducted in the past to identify those natural water sources which would be protected as rare habitats and which may fall under regulatory authority of the Clean Water Act (CWA) of 1997. This report identifies and summarizes previous studies of NTS natural water sources, and identifies the current DOE management practices related to the protection of NTS wetlands. This report also presents management goals specific for NTS wetlands that incorporate the intent of existing wetlands legislation, the principles of ecosystem management, and the interests of regional land managers and other stakeholders.

  15. Nevada National Security Site Waste Acceptance Criteria

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Management

    2010-09-03

    This document establishes the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO) Nevada National Security Site Waste Acceptance Criteria (NNSSWAC). The NNSSWAC provides the requirements, terms, and conditions under which the Nevada National Security Site (NNSS) will accept low-level radioactive waste and mixed low-level waste for disposal. The NNSSWAC includes requirements for the generator waste certification program, characterization, traceability, waste form, packaging, and transfer. The criteria apply to radioactive waste received at the NNSS Area 3 and Area 5 Radioactive Waste Management Complex for disposal. The NNSA/NSO and support contractors are available to assist you in understanding or interpreting this document. For assistance, please call the NNSA/NSO Waste Management Project at (702) 295-7063 or fax to (702) 295-1153.

  16. Nevada National Security Site Waste Acceptance Criteria

    International Nuclear Information System (INIS)

    2010-01-01

    This document establishes the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO) Nevada National Security Site Waste Acceptance Criteria (NNSSWAC). The NNSSWAC provides the requirements, terms, and conditions under which the Nevada National Security Site (NNSS) will accept low-level radioactive waste and mixed low-level waste for disposal. The NNSSWAC includes requirements for the generator waste certification program, characterization, traceability, waste form, packaging, and transfer. The criteria apply to radioactive waste received at the NNSS Area 3 and Area 5 Radioactive Waste Management Complex for disposal. The NNSA/NSO and support contractors are available to assist you in understanding or interpreting this document. For assistance, please call the NNSA/NSO Waste Management Project at (702) 295-7063 or fax to (702) 295-1153.

  17. Nevada National Security Site Waste Acceptance Criteria

    International Nuclear Information System (INIS)

    2011-01-01

    This document establishes the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO) Nevada National Security Site Waste Acceptance Criteria (NNSSWAC). The NNSSWAC provides the requirements, terms, and conditions under which the Nevada National Security Site (NNSS) will accept low-level radioactive waste and mixed low-level waste for disposal. The NNSSWAC includes requirements for the generator waste certification program, characterization, traceability, waste form, packaging, and transfer. The criteria apply to radioactive waste received at the NNSS Area 3 and Area 5 Radioactive Waste Management Complex for disposal. The NNSA/NSO and support contractors are available to assist you in understanding or interpreting this document. For assistance, please call the NNSA/NSO Waste Management Project at (702) 295-7063 or fax to (702) 295-1153.

  18. Nevada Test Site Radiation Protection Program

    Energy Technology Data Exchange (ETDEWEB)

    Radiological Control Managers' Council, Nevada Test Site

    2007-08-09

    Title 10 Code of Federal Regulations (CFR) 835, 'Occupational Radiation Protection', establishes radiation protection standards, limits, and program requirements for protecting individuals from ionizing radiation resulting from the conduct of U.S. Department of Energy (DOE) activities. 10 CFR 835.101(a) mandates that DOE activities be conducted in compliance with a documented Radiation Protection Program (RPP) as approved by DOE. This document promulgates the RPP for the Nevada Test Site (NTS), related (onsite or offsite) DOE National Nuclear Security Administration Nevada Site Office (NNSA/NSO) operations, and environmental restoration offsite projects.

  19. Helping Nevada School Children Become Sun Smart

    Centers for Disease Control (CDC) Podcasts

    2017-11-28

    This podcast features Christine Thompson, Community Programs Manager at the Nevada Cancer Coalition, and author of a recent study detailing a school-based program to help Nevada school children establish healthy sun safety habits and decrease UV exposure. Christine answers questions about her research and what impact her what impact the program had on children’s skin health.  Created: 11/28/2017 by Preventing Chronic Disease (PCD), National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 11/28/2017.

  20. Nevada Test Site Environmental Report 2008

    Energy Technology Data Exchange (ETDEWEB)

    Cathy A. Wills

    2009-09-01

    The Nevada Test Site Environmental Report (NTSER) 2008 was prepared to meet the information needs of the public and the requirements and guidelines of the U.S. Department of Energy (DOE) for annual site environmental reports. It was prepared by National Security Technologies, LLC (NSTec), for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO). This and previous years’ NTSERs are posted on the NNSA/NSO website at http://www.nv.doe.gov/library/publications/aser.aspx.