Sample records for taylor creek rhyolite

  1. The Taylor Creek Rhyolite of New Mexico: a rapidly emplaced field of lava domes and flows

    USGS Publications Warehouse

    Duffield, W.A.; Dalrymple, G.B.

    1990-01-01

    The Tertiary Taylor Creek Rhyolite of southwest New Mexico comprises at least 20 lava domes and flows. Each of the lavas was erupted from its own vent, and the vents are distributed throughout a 20 km by 50 km area. The volume of the rhyolite and genetically associated pyroclastic deposits is at least 100 km3 (denserock equivalent). The rhyolite contains 15%-35% quartz, sanidine, plagioclase, ??biotite, ??hornblende phenocrysts. Quartz and sanidine account for about 98% of the phenocrysts and are present in roughly equal amounts. With rare exceptions, the groundmass consists of intergrowths of fine-grained silica and alkali feldspar. Whole-rock major-element composition varies little, and the rhyolite is metaluminous to weakly peraluminous; mean SiO2 content is about 77.5??0.3%. Similarly, major-element compositions of the two feldsparphenocryst species also are nearly constant. However, whole-rock concentrations of some trace-elements vary as much as several hundred percent. Initial radiometric age determinations, all K-Ar and fission track, suggest that the rhyolite lava field grew during a period of at least 2 m.y. Subsequent 40Ar/39Ar ages indicate that the period of growth was no more than 100 000 years. The time-space-composition relations thus suggest that the Taylor Creek Rhyolite was erupted from a single magma reservoir whose average width was at least 30 km, comparable in size to several penecontemporaneous nearby calderas. However, this rhyolite apparently is not related to a caldera structure. Possibly, the Taylor Creek Phyolite magma body never became sufficiently volatile rich to produce a large-volume pyroclastic eruption and associated caldera collapse, but instead leaked repeatedly to feed many relatively small domes and flows. The new 40Ar/39Ar ages do not resolve preexisting unknown relative-age relations among the domes and flows of the lava field. Nonetheless, the indicated geologically brief period during which Taylor Creek Rhyolite magma was

  2. Compositional gradients in large reservoirs of silicic magma as evidenced by ignimbrites versus Taylor Creek Rhyolite lava domes

    NASA Astrophysics Data System (ADS)

    Duffield, Wendell A.; Ruiz, Joaquin

    1992-04-01

    The Taylor Creek Rhyolite of southwest New Mexico consists of 20 lava domes and flows that were emplaced during a period of a few thousand years or less in late Oligocene time. Including genetically associated pyroclastic deposits, which are about as voluminous as the lava domes and flows, the Taylor Creek Rhyolite represents roughly 100 km3 of magma erupted from vents distributed throughout an area of several hundred square kilometers. Major-element composition is metaluminous to weakly peraluminous high-silica rhyolite and is nearly constant throughout the lava field. The magma reservoir for the Taylor Creek Rhyolite was vertically zoned in trace elements, 87Sr/86Sr, and phenocryst abundance and size. Mean trace-element concentrations, ranges in concentrations, and element-pair correlations are similar to many subalkaline silicic ignimbrites. However, the polarity of the zonation was opposite that in reservoirs for ignimbrites, for most constituents. For example, compared to the Bishop Tuff, only 87Sr/86Sr and Sc increased upward in both reservoirs. Quite likely, a dominant but nonerupted volume of the magma reservoir for the Taylor Creek Rhyolite was zoned like that for the Bishop Tuff, whereas an erupted, few-hundred-meter-thick cap on the magma body was variably contaminated by roof rocks whose contribution to this part of the magma system moderated relatively extreme trace-element concentrations of uncontaminated Taylor Creek Rhyolite but did not change the sense of correlation for most element pairs. The contaminant probably was a Precambrian rock of broadly granitic composition and with very high 87Sr/86Sr. Although examples apparently are not yet reported in the literature, evidence for a similar thin contaminated cap on reservoirs for large-volume silicic ignimbrites may exist in the bottom few meters of ignimbrites or perhaps only in the pumice fallout that normally immediately precedes ignimbrite emplacement. 87Sr/86Sr in sanidine phenocrysts of the

  3. Compositional gradients in large reservoirs of silicic magma as evidenced by ignimbrites versus Taylor Creek Rhyolite lava domes

    USGS Publications Warehouse

    Duffield, W.A.; Ruiz, J.

    1992-01-01

    The Taylor Creek Rhyolite of southwest New Mexico consists of 20 lava domes and flows that were emplaced during a period of a few thousand years or less in late Oligocene time. Including genetically associated pyroclastic deposits, which are about as voluminous as the lava domes and flows, the Taylor Creek Rhyolite represents roughly 100 km3 of magma erupted from vents distributed throughout an area of several hundred square kilometers. Major-element composition is metaluminous to weakly peraluminous high-silica rhyolite and is nearly constant throughout the lava field. The magma reservoir for the Taylor Creek Rhyolite was vertically zoned in trace elements, 87Sr/86Sr, and phenocryst abundance and size. Mean trace-element concentrations, ranges in concentrations, and element-pair correlations are similar to many subalkaline silicic ignimbrites. However, the polarity of the zonation was opposite that in reservoirs for ignimbrites, for most constituents. For example, compared to the Bishop Tuff, only 87Sr/86Sr and Sc increased upward in both reservoirs. Quite likely, a dominant but nonerupted volume of the magma reservoir for the Taylor Creek Rhyolite was zoned like that for the Bishop Tuff, whereas an erupted, few-hundred-meter-thick cap on the magma body was variably contaminated by roof rocks whose contribution to this part of the magma system moderated relatively extreme trace-element concentrations of uncontaminated Taylor Creek Rhyolite but did not change the sense of correlation for most element pairs. The contaminant probably was a Precambrian rock of broadly granitic composition and with very high 87Sr/86Sr. Although examples apparently are not yet reported in the literature, evidence for a similar thin contaminated cap on reservoirs for large-volume silicic ignimbrites may exist in the bottom few meters of ignimbrites or perhaps only in the pumice fallout that normally immediately precedes ignimbrite emplacement. 87Sr/86Sr in sanidine phenocrysts of the

  4. Taylor instability in rhyolite lava flows

    NASA Technical Reports Server (NTRS)

    Baum, B. A.; Krantz, W. B.; Fink, J. H.; Dickinson, R. E.

    1989-01-01

    A refined Taylor instability model is developed to describe the surface morphology of rhyolite lava flows. The effect of the downslope flow of the lava on the structures resulting from the Taylor instability mechanism is considered. Squire's (1933) transformation is developed for this flow in order to extend the results to three-dimensional modes. This permits assessing why ridges thought to arise from the Taylor instability mechanism are preferentially oriented transverse to the direction of lava flow. Measured diapir and ridge spacings for the Little and Big Glass Mountain rhyolite flows in northern California are used in conjunction with the model in order to explore the implications of the Taylor instability for flow emplacement. The model suggests additional lava flow features that can be measured in order to test whether the Taylor instability mechanism has influenced the flows surface morphology.

  5. 33 CFR 207.170d - Taylor Creek, navigation lock (S-193) across the entrance to Taylor Creek at Lake Okeechobee...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Taylor Creek, navigation lock (S-193) across the entrance to Taylor Creek at Lake Okeechobee, Okeechobee, Fla.; use, administration..., DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE NAVIGATION REGULATIONS § 207.170d Taylor Creek, navigation lock...

  6. 33 CFR 207.170d - Taylor Creek, navigation lock (S-193) across the entrance to Taylor Creek at Lake Okeechobee...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Taylor Creek, navigation lock (S-193) across the entrance to Taylor Creek at Lake Okeechobee, Okeechobee, Fla.; use, administration..., DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE NAVIGATION REGULATIONS § 207.170d Taylor Creek, navigation lock...

  7. 33 CFR 117.335 - Taylor Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Taylor Creek. 117.335 Section 117.335 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.335 Taylor Creek. The draw of US441 bridge, mile 0...

  8. 33 CFR 117.335 - Taylor Creek.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Taylor Creek. 117.335 Section 117.335 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.335 Taylor Creek. The draw of US441 bridge, mile 0...

  9. Physical Volcanology and Geochemistry of the Brown's Creek Rhyolite Lava in the Western Snake River Plain, Idaho.

    NASA Astrophysics Data System (ADS)

    Steenberg, L.; Gruber, B.; Boroughs, S.; Wolff, J.

    2015-12-01

    The Brown's Creek rhyolite (BCR), ~70 km south of Boise, Idaho, erupted during a period of widespread rhyolitic volcanism in southwestern Idaho during the middle Miocene. However, the Brown's Creek unit has several characteristics that are unusual relative to near contemporaneous units in the Central Snake Rive Plain (CSRP) and units in the Western Snake River Plain (WSRP). The BCR can contain up to 40% phenocrysts, with some feldspar and quartz crystals in excess of 2 cm in diameter. A proximal vent location is particularly well exposed in the BCR, and appears as an elongated topographic "dome" with pervasive, chaotic and steep flow banding, ramp structures, and breccias. Evidence of dome building activity is also represented by a matrix supported deposit of ash and poorly sorted, angular, rhyolite clasts up to boulder size; which crops out in a small area near the vent. The BCR is among numerous units in the CSRP and WSRP that show evidence of interaction with ancient Lake Idaho (e.g. silicification, opalized zones, pepperites, etc), but the unconformity with the sedimentary rocks of the lake and its feeder streams, is extremely well preserved in the Brown's Creek rhyolite. Geochemically, the Brown's Creek rhyolite shows greater compositional variation in comparison to other individual units in the region. This variation (e.g. Ba/Sr and Zr/Nb) may be a result of variable crystal cargo in hand samples, but could potentially represent a zoned magma body, which is also extremely rare in the CSRP or WSRP. A limited number of samples have trace element concentrations/ratios (e.g. Rb, U, and Th) that may indicate the presence of a second unit underlying the dominant outcrops of BCR, but Nb/Ta ratios are relatively invariant across the entire BCR suite; if there are two units in the BCR, their sources are the same or very similar.

  10. Volcanic Stratigraphy of the Quaternary Rhyolite Plateau in Yellowstone National Park

    USGS Publications Warehouse

    Christiansen, Robert L.; Blank, H. Richard

    1972-01-01

    The volcanic sequence of the Quaternary Yellowstone plateau consists of rhyolites and basalts representing three volcanic cycles. The major events of each cycle were eruption of a voluminous ash-flow sheet and formation of a large collapse caldera. Lesser events of each cycle were eruption of precaldera and postcaldera rhyolitic lava flows and marginal basaltic lavas. The three major ash-flow sheets are named and designated in this report as formations within the Yellowstone Group. The lavas are assigned to newly named formations organized around the three ash-flow sheets of the Yellowstone Group to represent the volcanic cycles. Rocks of the first volcanic cycle comprise the precaldera Junction Butte Basalt and rhyolite of Broad Creek; the Huckleberry Ridge Tuff of the Yellowstone Group; and the postcaldera Lewis Canyon Rhyolite and basalt of The Narrows. Rocks of the second volcanic cycle do not crop out within Yellowstone National Park, and only the major unit, the Mesa Falls Tuff of the Yellowstone Group, is named here. The third volcanic cycle is represented by the precaldera Mount Jackson Rhyolite and Undine Falls Basalt; the Lava Creek Tuff of the Yellowstone Group; and the postcaldera Plateau Rhyolite and five post-Lava Creek basaltic sequences. Collapse to form the compound and resurgent Yellowstone caldera was related to eruption of the Lava Creek Tuff. The Plateau Rhyolite is divided into six members - the Mallard Lake, Upper Basin, Obsidian Creek, Central Plateau, Shoshone Lake Tuff, and Roaring Mountain Members; all but the Mallard Lake postdate resurgent doming of the caldera. The basalts are divided into the Swan Lake Flat Basalt, Falls River Basalt, basalt of Mariposa Lake, Madison River Basalt, and Osprey Basalt. Sediments are intercalated in the volcanic section below the Huckleberry Ridge and Mesa Falls Tuffs and within the Junction Butte Basalt, sediments and basalts of The Narrows, Undine Falls Basalt, Plateau Rhyolite, and Osprey Basalt.

  11. Limnology of Taylor Creek impoundment : with reference to other bodies in Upper St Johns River Basin, Florida

    USGS Publications Warehouse

    Goolsby, D.A.; McPherson, Benjamin F.

    1978-01-01

    Taylor Creek Impoundment, on the western part of the upper St. Johns basin, Fla., provides flood control and flow regulation. The 4,000-acre impoundment was first filled in 1969. The water was of relatively poor quality during the first three years of its existence, 1970-72. The impoundment is deep enough for thermal stratification, and a thermocline usually develops at 8 to 10 feet. During 1970-72 the hypolimnion remained anaerobic for more than six months. The poor water quality is attributed to the decomposition of flooded vegetation, of soil organic matter, and to heavy growths of phytoplankton and duckweed stimulated by an abundant supply of nutrients. Since 1972, the quality of the water has improved because of flushing of the impoundment and depletion of leachable nutrients and soil organic matter. The water is now similar in quality to that of nearby Wolf and Jane Green Creeks. Large releases of water may produce velocities great enough to resuspend bottom sediments several miles downstream where Taylor Creek flows into Lake Poinsett. (Woodard-USGS)

  12. New Data on mid-Miocene Rhyolite Volcanism in Eastern Oregon Extend Early, co-CRBG Rhyolite Flare up and Constrain Storage Sites of Grande Ronde Flood Basalts

    NASA Astrophysics Data System (ADS)

    Streck, M. J.; Ferns, M. L.; McIntosh, W. C.

    2015-12-01

    The classical view of relating mid-Miocene rhyolites of the tri-state area of Oregon, Nevada, and Idaho to the flood basalts of the Columbia River Basalt was that a mantle plume impinging along the Oregon-Idaho border first causes eruption of the flood basalts but shortly thereafter causes generation of rhyolites at the McDermitt volcanic field from which then hot-spot track rhyolites developed progressively younging towards Yellowstone. More recent work reveals rhyolites as old as found at McDermitt (~16.5 Ma) to occur along a wide E-W tangent along the Oregon-Nevada-Idaho border. And now, our data extend such early rhyolites (>16 Ma) to several locations further north within and in the periphery of the Lake Owyhee Volcanic Field (LOVF) adding to the geographically orphaned old age of 16.7 Ma of the Silver City Rhyolite, Idaho. Hence, the rhyolite flare-up associated with flood basalt magmatism occurred within a circular area of ~400 km centered 100 km NNE of McDermitt. Consequently, no south-to-north progression exists in the onset of rhyolite volcanism; instead, rhyolites started up at the same time over this large area. Province-wide rhyolite volcanism was strongest between ~16.4 and 15.4 Ma coincident with eruptions of the most voluminous member of the CRBG - the Grande Ronde Basalt (GRB). Field evidence for such bimodal volcanism consists of intercalated local GRB units with the Dinner Creek Tuff and Littlefield Rhyolite in the Malheur River Gorge corridor. GRB eruption sites exist and were likely fed from reservoirs residing below or near rhyolitic chambers. Presently, we have petrological evidence for pinning down GRB storages sites to areas from where rhyolites of the Dinner Creek Tuff and lava flows of the Littlefield Rhyolite erupted. In summary, input of GRG and other CRBG magmas were driving co-CRBG rhyolite volcanism which in turn may have influenced whether flood basalt magmas erupted locally or travelled in dikes to more distally located areas.

  13. Northeastern Florida Bay estuarine creek data, water years 1996-2000

    USGS Publications Warehouse

    Hittle, Clinton D.; Zucker, Mark A.

    2004-01-01

    From October 1995 to September 2000 (water years 1996-2000), continuous 15-minute stage, water velocity, salinity, and water temperature data were collected at seven estuarine creeks that flow into northeastern Florida Bay. These creeks include West Highway Creek, Stillwater Creek, Trout Creek, Mud Creek, Taylor River, Upstream Taylor River, and McCormick Creek. Discharge was computed at 15-minute intervals using mean water velocity and the cross-sectional area of the channel. Fifteen-minute unit values are presented for comparison of the quantity, quality, timing, and distribution of flows through the creeks. Revised discharge estimation formulas are presented for three noninstrumented sites (East Highway Creek, Oregon Creek and Stillwater Creek) that utilize an improved West Highway discharge rating. Stillwater Creek and Upstream Taylor River were originally noninstrumented sites; both were fully instrumented in 1999. Discharge rating equations are presented for these sites and were developed using a simple linear regression.

  14. Aircraft remote sensing of soil moisture and hydrologic parameters, Taylor Creek, Florida, and Little River, Georgia, 1979 data report

    NASA Technical Reports Server (NTRS)

    Jackson, T. J.; Schmugge, T. J.; Allen, L. H., Jr.; Oneill, P.; Slack, R.; Wang, J.; Engman, E. T.

    1981-01-01

    Experiments were conducted to evaluate aircraft remote sensing techniques for hydrology in a wide range of physiographic and climatic regions using several sensor platforms. The data were collected in late 1978 and during 1979 in two humid areas--Taylor Creek, Fla., and Little River, Ga. Soil moisture measurements and climatic observations are presented as well as the remote sensing data collected using thermal infrared, passive microwave, and active microwave systems.

  15. Geologic framework, regional aquifer properties (1940s-2009), and spring, creek, and seep properties (2009-10) of the upper San Mateo Creek Basin near Mount Taylor, New Mexico

    USGS Publications Warehouse

    Langman, Jeff B.; Sprague, Jesse E.; Durall, Roger A.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Forest Service, examined the geologic framework, regional aquifer properties, and spring, creek, and seep properties of the upper San Mateo Creek Basin near Mount Taylor, which contains areas proposed for exploratory drilling and possible uranium mining on U.S. Forest Service land. The geologic structure of the region was formed from uplift of the Zuni Mountains during the Laramide Orogeny and the Neogene volcanism associated with the Mount Taylor Volcanic Field. Within this structural context, numerous aquifers are present in various Paleozoic and Mesozoic sedimentary formations and the Quaternary alluvium. The distribution of the aquifers is spatially variable because of the dip of the formations and erosion that produced the current landscape configuration where older formations have been exhumed closer to the Zuni Mountains. Many of the alluvial deposits and formations that contain groundwater likely are hydraulically connected because of the solid-matrix properties, such as substantive porosity, but shale layers such as those found in the Mancos Formation and Chinle Group likely restrict vertical flow. Existing water-level data indicate topologically downgradient flow in the Quaternary alluvium and indiscernible general flow patterns in the lower aquifers. According to previously published material and the geologic structure of the aquifers, the flow direction in the lower aquifers likely is in the opposite direction compared to the alluvium aquifer. Groundwater within the Chinle Group is known to be confined, which may allow upward migration of water into the Morrison Formation; however, confining layers within the Chinle Group likely retard upward leakage. Groundwater was sodium-bicarbonate/sulfate dominant or mixed cation-mixed anion with some calcium/bicarbonate water in the study area. The presence of the reduction/oxidation-sensitive elements iron and manganese in groundwater indicates reducing

  16. Early miocene bimodal volcanism, Northern Wilson Creek Range, Lincoln County, Nevada

    USGS Publications Warehouse

    Willis, J.B.; Willis, G.C.

    1996-01-01

    Early Miocene volcanism in the northern Wilson Creek Range, Lincoln County, Nevada, produced an interfingered sequence of high-silica rhyolite (greater than 74% SiO2) ash-flow tuffs, lava flows and dikes, and mafic lava flows. Three new potassium-argon ages range from 23.9 ?? 1.0 Ma to 22.6 ?? 1.2 Ma. The rocks are similar in composition, stratigraphic character, and age to the Blawn Formation, which is found in ranges to the east and southeast in Utah, and, therefore, are herein established as a western extension of the Blawn Formation. Miocene volcanism in the northern Wilson Creek Range began with the eruption of two geochemically similar, weakly evolved ash-flow tuff cooling units. The lower unit consists of crystal-poor, loosely welded, lapilli ash-flow tuffs, herein called the tuff member of Atlanta Summit. The upper unit consists of homogeneous, crystal-rich, moderately to densely welded ash-flow tuffs, herein called the tuff member of Rosencrans Peak. This unit is as much as 300 m thick and has a minimum eruptive volume of 6.5 km3, which is unusually voluminous for tuffs in the Blawn Formation. Thick, conspicuously flow-layered rhyolite lava flows were erupted penecontemporaneously with the tuffs. The rhyolite lava flows have a range of incompatible trace element concentrations, and some of them show an unusual mixing of aphyric and porphyritic magma. Small volumes of alkaline, vesicular, mafic flows containing 50 weight percent SiO2 and 2.3 weight percent K2O were extruded near the end of the rhyolite volcanic activity. The Blawn Formation records a shift in eruptive style and magmatic composition in the northern Wilson Creek Range. The Blawn was preceded by voluminous Oligocene eruptions of dominantly calc-alkaline orogenic magmas. The Blawn and younger volcanic rocks in the area are low-volume, bimodal suites of high-silica rhyolite tuffs and lava flows and mafic lava flows.

  17. Genesis of the post-caldera eastern Upper Basin Member rhyolites, Yellowstone, WY: from volcanic stratigraphy, geochemistry, and radiogenic isotope modeling

    NASA Astrophysics Data System (ADS)

    Pritchard, Chad J.; Larson, Peter B.

    2012-08-01

    An array of samples from the eastern Upper Basin Member of the Plateau Rhyolite (EUBM) in the Yellowstone Plateau, Wyoming, were collected and analyzed to evaluate styles of deposition, geochemical variation, and plausible sources for low δ18O rhyolites. Similar depositional styles and geochemistry suggest that the Tuff of Sulphur Creek and Tuff of Uncle Tom's Trail were both deposited from pyroclastic density currents and are most likely part of the same unit. The middle unit of the EUBM, the Canyon flow, may be composed of multiple flows based on a wide range of Pb isotopic ratios (e.g., 206Pb/204Pb ranges from 17.54 to 17.86). The youngest EUBM, the Dunraven Road flow, appears to be a ring fracture dome and contains isotopic ratios and sparse phenocrysts that are similar to extra-caldera rhyolites of the younger Roaring Mountain Member. Petrologic textures, more radiogenic 87Sr/86Sr in plagioclase phenocrysts (0.7134-0.7185) than groundmass and whole-rock ratios (0.7099-0.7161), and δ18O depletions on the order of 5‰ found in the Tuff of Sulphur Creek and Canyon flow indicate at least a two-stage petrogenesis involving an initial source rock formed by assimilation and fractional crystallization processes, which cooled and was hydrothermally altered. The source rock was then lowered to melting depth by caldera collapse and remelted and erupted. The presence of a low δ18O extra-caldera rhyolite indicates that country rock may have been hydrothermally altered at depth and then assimilated to form the Dunraven Road flow.

  18. Strawberry Rhyolites, Oregon: Northwestern extent of mid-Miocene flood basalt related rhyolites of the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Steiner, A. R.; Streck, M. J.

    2011-12-01

    Rhyolitic volcanism associated with the Columbia River-Steens flood basalts of the Pacific Northwest has traditionally been viewed to be centered at McDermitt caldera near the Oregon-Nevada border starting at ~16.5 Ma. In recent years, more rhyolitic centers along this latitude with ages between 16.5-15.5 Ma have been identified and associated with the inception of the Yellowstone hotspot. However the footprint of plume-head related rhyolites becomes much larger when silicic centers of mid-Miocene age in eastern Oregon are included extending the distribution of such rhyolites to areas near the towns of Baker City and John Day ~250 km north of McDermitt. This study addresses one of these rhyolitic centers that was virtually unknown and that constitutes the northwestern extent of mid-Miocene rhyolites. Rhyolites are centered ~40 km SSW of John Day and are considered part of the Strawberry Volcanic Field (SVF), which consists of a diverse group of volcanic rocks ranging from basalt to rhyolite with abundant intermediate compositions. One existing age date of 17.3 Ma ± 0.36 (Robyn, 1977) - if confirmed by our ongoing study - places these rhyolites at the very onset of plume-head related rhyolites. Strawberry rhyolitic lavas are most voluminous in the southwestern portion of the SVF covering approximately 500 km2 between Bear and Logan Valley. The rhyolitic lavas tend to be phenocryst-poor (<3%) and range from obsidian to devitrified flow banded rhyolites. The major phenocryst phases include plagioclase, quartz, and occasional biotite. Field evidence suggests that the aphyric high-silica rhyolite lavas (~77 wt. % SiO2) erupted first, followed by rhyolite lava flows with increasing phenocryst proportions and decreasing SiO2 (70 wt. %). Lastly, phenocryst-rich dacite lava erupted on top, capping the rhyolite. There is no evidence of significant time gaps between lavas flows, suggesting eruption in short succession. Rhyolites from the SVF are high-K, calc-alkaline lavas

  19. Making rhyolite in a basalt crucible

    NASA Astrophysics Data System (ADS)

    Eichelberger, John

    2016-04-01

    Iceland has long attracted the attention of those concerned with the origin of rhyolitic magmas and indeed of granitic continental crust, because it presents no alternative for such magmas other than deriving them from a basaltic source. Hydrothermally altered basalt has been identified as the progenitor. The fact that rhyolite erupts as pure liquid requires a process of melt-crustal separation that is highly efficient despite the high viscosity of rhyolite melt. Volcanoes in Iceland are foci of basaltic magma injection along the divergent plate boundary. Repeated injection produces remelting, digestion, and sometimes expulsion or lateral withdrawal of material resulting in a caldera, a "crucible" holding down-dropped and interlayered lava flows, tephras, and injected sills. Once melting of this charge begins, a great deal of heat is absorbed in the phase change. Just 1% change in crystallinity per degree gives a melt-present body an effective heat capacity >5 times the subsolidus case. Temperature is thus buffered at the solidus and melt composition at rhyolite. Basalt inputs are episodic ("fires") so likely the resulting generation of rhyolite by melting is too. If frequent enough to offset cooling between events, rhyolite melt extractions will accumulate as a rhyolite magma reservoir rather than as discrete crystallized sills. Evidently, such magma bodies can survive multiple firings without themselves erupting, as the 1875 eruption of Askja Caldera of 0.3 km3 of rhyolite equilibrated at 2-km depth without previous leakage over a ten-millennium period and the surprise discovery of rhyolite magma at 2-km depth in Krafla suggest. Water is required for melting; otherwise melting cannot begin at a temperature lower than that of the heat source. Because the solubility of water in melt is pressure-dependent and almost zero at surface pressure, there must be a minimum depth at which basalt-induced melting can occur and a rhyolite reservoir sustained. In practice, the

  20. The Rhyolite Flare-up of the Columbia River Basalt Province and its Bearing on Plume vs. Non-plume Models

    NASA Astrophysics Data System (ADS)

    Streck, M. J.; Ferns, M. L.

    2012-12-01

    The decades-long controversy as to whether the Columbia River Basalt province results from arrival of a deep mantle plume is far from over, as new non-plume models are proposed. Age-progressive rhyolites of the Snake River Plain are a centerpiece to a migrating plume model that ties mid-Miocene flood basalt magmatism to the present location of the Yellowstone hotspot. However voluminous mid-Miocene rhyolites coeval with the flood basalts of the Columbia River Basalt province have received little attention. These long-known but relatively underappreciated rhyolite occurrences in eastern Oregon and neighboring areas erupted across the province over a narrow time window making the Columbia River province a strongly bimodal (basalt-rhyolite) Large Igneous Province. The entire rhyolite distribution area has roughly a circular area of about a diameter of 300 km and stretches from rhyolite centers near the towns of Baker City and John Day, Oregon in the north to rhyolite centers of the High Rock Desert, Nevada in the SW and the Jarbidge Rhyolite, Idaho in the SE. Oldest rhyolites are ~16.5 Ma in age and occur both along the southern E-W tangent (including McDermitt) and, in lesser volumes, in the central to northern sector. The considerable data that have been generated over the last few years on rhyolites of the southern sector is now being supplemented by new data that we have begun collecting on rhyolites further north. Province-wide rhyolite volcanism was strongest between ~16.4 and 15.4 Ma coincident with eruptions of the most voluminous member of the CRBG - the Grande Ronde Basalt. This widespread rhyolite volcanism indicates that CRBG crustal inputs were focused during this narrow time window over a large area. Magmas in the upper Grande Ronde Basalt that compositionally correlate with glassy mafic inclusions in the rhyolitic Dinner Creek Tuff effectively place one CRBG crustal storage site below a major silicic center. Youngest rhyolites range from ~14.5 to 12

  1. Petrogensis of rhyolitic domes of Dastjerd (SE Qom)

    NASA Astrophysics Data System (ADS)

    Askari, Nasim; Kheirkhah, Monireh; Hashem Emami, Mohamad

    2010-05-01

    The study area is located in South Eastern Qom; this area is marginal part of SW Central Iran, located in Urumieh- Dokhtar magmatic belt. Rhyolitic domes (Post Eocene) as endogenous (crypto dome) are along Meyem slip-fault, that this fault probably is effective in emplacement and magma ascent. The ryholitic rocks contain some phenocrysts of garnets, plagioclases and biotits. The groundmasses are consisting of plagioclase, K-feldspar and quartz. Rhyolitic rocks have calc alkaline trends and base on chemical composition of rhyolite rocks and mica bearing. The source of magma is S-type and per aluminums which belongs to collision environment. It is suggested the role of continental crust in generation rhyolitic rocks. Because of the garnet area is an early crystallizing phase and is only confined to rhyolite, it is inferred that the garnet did not crystallize in more basic magmas and that the rhyolite could not have been derived from a basic magma by crystal fractionation. Keywords: Rhyolitic, slip-fault, collision, S-type, endogenous

  2. Late Pleistocene eruptive history of the Mono Craters rhyolites, eastern California, from U-Th dating of explosive and effusive products

    NASA Astrophysics Data System (ADS)

    Marcaida, M.; Vazquez, J. A.; Calvert, A. T.; Miller, J. S.

    2016-12-01

    During late Pleistocene-Holocene time, repeated explosive and effusive eruptions of high-silica rhyolite magma south of Mono Lake, California, have produced a chain of massive domes known as the Mono Craters and a time-series of tephra deposits preserved in sediments of the Wilson Creek formation of ancestral Mono Lake. The record of late Holocene volcanism at Mono Craters is relatively well constrained by tephrostratigraphy and 14C dating, and the timing of late Pleistocene eruptions is similarly well constrained by tephrochronology and magnetostratigraphy of the Wilson Creek formation. However, the chronology of eruptions for the Mono Craters chain, comprising at least 28 individual domes, has thus far been based on age estimates from hydration rind dating of obsidian that is highly dependent on local calibration. We constrain the timing of late Pleistocene dome emplacement by linking independently dated Wilson Creek tephras to their dome equivalents in the Mono Craters using combined titanomagnetite geochemistry and U-Th geochronology. Ion microprobe 238U-230Th dating of unpolished allanite and zircon rims gives isochron dates of ca. 42 ka, ca. 38 ka, ca. 26 ka, and ca. 20 ka for domes 19, 24, 31 (newly recognized), and 11 of the Mono Craters, respectively. These domes are biotite-bearing rhyolites with titanomagnetites that are compositionally identical to those from several Wilson Creek tephras. Specifically, we correlate Ash 15, Ash 7, and Ash 3 of the Wilson Creek formation to domes 19, 31, and 11 of the Mono Craters, respectively, based on matching titanomagnetite compositions and indistinguishable U-Th ages. 40Ar/39Ar dating of single sanidines from domes 19 and 31 yield mean dates that are 10 k.y. older than their corresponding U-Th dates, likely due to excess argon from melt inclusions and/or incompletely re-equilibrated antecrysts. Based on our new U-Th isochron date of ca. 34 ka for allanite-zircon from Ash 8 pumice and the ca. 26-27 ka age of Ash 7

  3. Show Me the Mush! - Constraints From Voluminous Rhyolitic Ignimbrites of Bimodal and Calc-alkaline Settings on the Applicability of a Mush Model

    NASA Astrophysics Data System (ADS)

    Streck, M. J.

    2012-12-01

    Mush models have been popular in explaining crystal-poor rhyolites of a variety of settings. The classical mush model requires an abundance of very crystal-rich (>50%), intermediate (dacitic) magmas that upon compaction expel their interstitial liquids that erupt to give rise to rhyolitic lava flows and ignimbrites. In volcanic systems, a critical part in evaluating a mush model rests on providing evidence for the existence of suitable crystal-rich intermediate magmas that are consistent with the petrology of the erupted rhyolites. In my evaluation, I focus on providing constraints of whether or not suitable crystal mushes are likely to have existed and were instrumental in the production of a select series of voluminous (>100 km3) rhyolitic ignimbrites. Furthermore, the volcanic framework of each selected ignimbrite is used for assessing questions of "eruptibility" of magma types. The three main evaluated units representing 'hot-dry-reduced' rhyolites of bimodal settings are the 16-15.4 Ma Dinner Creek Tuff, the 9.7 Ma Devine Canyon Tuff, and 7.1 Ma Rattlesnake Tuff. All three tuffs erupted in eastern Oregon within a basalt-rhyolite suite. The key feature that makes them particularly valuable for this discussion is that each of the tuffs erupted a co-magmatic component that tracks the intermediate to mafic underpinnings to the rhyolitic magma. This allows a direct assessment of what intermediate magmas residing in close spatial proximity to the rhyolites looked like. On the other hand, other characteristics such as degree of chemical zoning, element trends, single or multiple cooling units, etc., vary considerably among the three tuffs thus covering a wide spectrum of rhyolites from bimodal settings. As representative of 'cool-wet-oxidized' rhyolites, I test applicability of the mush model on the tuffs and associated lavas of the Oligocene San Luis caldera system. This system represents strongly confocal and voluminous eruptions that are closely spaced in time at

  4. Mid-Tertiary magmatism in western Big Bend National Park, Texas, U.S.A.: Evolution of basaltic source regions and generation of peralkaline rhyolite

    NASA Astrophysics Data System (ADS)

    Parker, Don F.; Ren, Minghua; Adams, David T.; Tsai, Heng; Long, Leon E.

    2012-07-01

    Tertiary magmatism in the Big Bend region of southwestern Texas spanned 47 to 17 Ma and included representatives of all three phases (Early, Main and Late) of the Trans-Pecos magmatic province. Early phase magmatism was manifested in the Alamo Creek Basalt, an alkalic lava series ranging from basalt to benmoreite, and silicic alkalic intrusions of the Christmas Mountains. Main phase magmatism in the late Eocene/early Oligocene produced Bee Mountain Basalt, a lava series ranging from hawaiite and potassic trachybasalt to latite, widespread trachytic lavas of Tule Mountain Trachyte and silicic rocks associated with the Pine Mountain Caldera in the Chisos Mountains. Late main phase magmatism produced trachyte lava and numerous dome complexes of peralkaline Burro Mesa Rhyolite (~ 29 Ma) in western Big Bend National Park. Late stage basaltic magmatism is sparsely represented by a few lavas in the Big Bend Park area, the adjacent Black Gap area and, most notably, in the nearby Bofecillos Mountains, where alkalic basaltic rocks were emplaced as lava and dikes concurrent with active normal faulting. Trace element modeling, Nd isotope ratios and calculated depths of segregation for estimated ancestral basaltic magmas suggest that Alamo Creek basalts (ɛNdt ~ 6.15 to 2.33) were derived from depths (~ 120 to 90 km) near the lithosphere/asthenosphere boundary at temperatures of ~ 1600 to1560 °C, whereas primitive Bee Mountain basalts (ɛNdt ~ 0.285 to - 1.20) may have been segregated at shallower depths (~ 80 to 50 km) and lower temperatures (~ 1520 to 1430 °C) within the continental lithosphere. Nb/La versus Ba/La plots suggest that all were derived from OIB-modified continental lithosphere. Late stage basaltic rocks from the Bofecillos Mountains may indicate a return to source depths and temperatures similar to those calculated for Alamo Creek Basalt primitive magmas. We suggest that a zone of melting ascended into the continental lithosphere during main-phase activity and

  5. Freshwater flow from estuarine creeks into northeastern Florida Bay

    USGS Publications Warehouse

    Hittle, Clinton; Patino, Eduardo; Zucker, Mark A.

    2001-01-01

    total measured freshwater entering northeastern Florida Bay. The mean monthly wet-season (May-October) flow at Trout Creek is about 340 cubic feet per second, compared to 55 cubic feet per second at West Highway Creek, 52 cubic feet per second at Taylor River, 49 cubic feet per second at Mud Creek, and 33 cubic feet per second at McCormick Creek. The other two flow signatures are the decline of freshwater discharge at McCormick Creek at the start of the El Nino event, and the absence of net-negative flows at West Highway Creek. The observed flow distribution within the study area, suggests that the overall flow direction of freshwater in the Everglades wetlands in the lower part of Taylor Slough may have a strong eastward flow component as water approaches the coastline. Data analysis also indicates that Trout Creek could potentially be used as a long-term monitoring station to estimate total freshwater flow into northeastern Florida Bay, provided that the remaining questions regarding flow patterns at McCormick Creek and the creeks in Long Sound are answered and that no major changes in flow characteristics occur in the future.

  6. The Mantle and Basalt-Crust Interaction Below the Mount Taylor Volcanic Field, New Mexico

    NASA Technical Reports Server (NTRS)

    Schrader, Christian M.; Crumpler, Larry S.; Schmidt, Marick E.

    2010-01-01

    The Mount Taylor Volcanic Field (MTVF) lies on the Jemez Lineament on the southeastern margin of the Colorado Plateau. The field is centered on the Mt. Taylor composite volcano and includes Mesa Chivato to the NE and Grants Ridge to the WSW. MTVF magmatism spans approximately 3.8-1.5 Ma (K-Ar). Magmas are dominantly alkaline with mafic compositions ranging from basanite to hy-basalt and felsic compositions ranging from ne-trachyte to rhyolite. We are investigating the state of the mantle and the spatial and temporal variation in basalt-crustal interaction below the MTVF by examining mantle xenoliths and basalts in the context of new mapping and future Ar-Ar dating. The earliest dated magmatism in the field is a basanite flow south of Mt. Taylor. Mantle xenolith-bearing alkali basalts and basanites occur on Mesa Chivato and in the region of Mt. Taylor, though most basalts are peripheral to the main cone. Xenolith-bearing magmatism persists at least into the early stages of conebuilding. Preliminary examination of the mantle xenolith suite suggests it is dominantly lherzolitic but contains likely examples of both melt-depleted (harzburgitic) and melt-enriched (clinopyroxenitic) mantle. There are aphyric and crystal-poor hawaiites, some of which are hy-normative, on and near Mt. Taylor, but many of the more evolved MTVF basalts show evidence of complex histories. Mt. Taylor basalts higher in the cone-building sequence contain >40% zoned plagioclase pheno- and megacrysts. Other basalts peripheral to Mt. Taylor and at Grants Ridge contain clinopyroxene and plagioclase megacrysts and cumulate-textured xenoliths, suggesting they interacted with lower crustal cumulates. Among the questions we are addressing: What was the chemical and thermal state of the mantle recorded by the basaltic suites and xenoliths and how did it change with time? Are multiple parental basalts (Si-saturated vs. undersaturated) represented and, if so, what changes in the mantle or in the tectonic

  7. A temporal stable isotopic (d18O, dD, d-excess) comparison in glacier meltwater streams, Taylor Valley, Antarctica

    USDA-ARS?s Scientific Manuscript database

    In this paper, we describe the importance of hyporheic dynamics within Andersen Creek and Von Guerard Stream, Taylor Valley, Antarctica, from the 2010-11 melt season using natural tracers. Water collection started at flow onset and continued, with weekly hyporheic zone sampling. The water d18O and d...

  8. An ion microprobe study of individual zircon phenocrysts from voluminous post-caldera rhyolites of the Yellowstone caldera

    NASA Astrophysics Data System (ADS)

    Watts, K. E.; Bindeman, I. N.; Schmitt, A. K.

    2010-12-01

    Following the formation of the Yellowstone caldera from the 640 ka supereruption of the Lava Creek Tuff (LCT), a voluminous episode of post-caldera volcanism filled the caldera with >600 km3 of low-δ18O rhyolite. Such low-δ18O signatures require remelting of 100s of km3 of hydrothermally altered (18O-depleted) rock in the shallow crust. We present a high resolution oxygen isotope and geochronology (U-Th and U-Pb) study of individual zircon crystals from seven of these voluminous post-caldera rhyolites in order to elucidate their genesis. Oxygen isotope and geochronology analyses of zircon were performed with an ion microprobe that enabled us to doubly fingerprint 25-30 µm diameter spots. Host groundmass glasses and coexisting quartz were analyzed in bulk for oxygen isotopes by laser fluorination. We find that zircons from the youngest (200-80 ka) post-caldera rhyolites have oxygen isotopic compositions that are in equilibrium with low-δ18O host groundmass glasses and quartz and are unzoned in oxygen and U-Th age. This finding is in contrast to prior work on older (500-250 ka) post-caldera rhyolites, which exhibit isotopic disequilibria and age zoning, including the presence of clearly inherited zircon cores. Average U-Th crystallization ages and δ18O zircon values for Pitchstone Plateau flow (81±7 ka, 2.8±0.2‰), West Yellowstone flow (118±8 ka, 2.8±0.1‰), Elephant Back flow (175±22 ka, 2.7±0.2‰) and Tuff of Bluff Point (176±20 ka, 2.7±0.1‰) are overlapping or nearly overlapping in age and identical in oxygen isotope composition within uncertainty (2 SE). New U-Pb geochronology and oxygen isotope data for the North Biscuit Basin flow establish that it has an age (188±33 ka) and δ18O signature (2.8±0.2‰) that is distinctive of the youngest post-caldera rhyolites. Conversely, the South Biscuit Basin flow has a heterogeneous zircon population with ages that range from 550-250 ka. In this unit, older and larger (200-400 µm) zircons have more

  9. The origin of low-K rhyolites from the mariana frontal arc

    NASA Astrophysics Data System (ADS)

    Meijer, A.

    1983-08-01

    Low-K rhyolites and overlying 2-pyroxene andesites, both of Late Eocene age, comprise the oldest volcanic units exposed on Saipan. The mineralogy and geologic setting of these rocks indicate they were erupted in a volcanic arc setting. The presence of andesite and lack of basalts of similar age suggest that the rhyolites are not part of a typical bimodal (basalt/rhyolite) suite. Major and trace element data indicate the Saipan andesites were not parental to the rhyolites. Out of various models evaluated for derivation of the rhyolites, the most reasonable involves crystal fractionation of a boninite series andesite that was very depleted in LIL elements. This andesite probably evolved from more mafic magmas which in turn were derived from the sub-arc mantle. Isotopic data suggest the mantle source for these magmas may have contained a minor seawater component.

  10. Shallow-storage conditions for the rhyolite of the 1912 eruption at Novarupta, Alaska

    USGS Publications Warehouse

    Coombs, Michelle L.; Gardner, James E.

    2001-01-01

    Recent studies have proposed contrasting models for the plumbing system that fed the 1912 eruption of Novarupta, Alaska. Here, we investigate the conditions under which the rhyolitic part of the erupted magma last resided in the crust prior to eruption. Geothermometry suggests that the rhyolite was held at ∼800-850 °C, and analyses of melt inclusions suggest that it was fluid saturated and contained ∼4 wt% water. Hydrothermal, water-saturated experiments on rhyolite pumice reveal that at those temperatures the rhyolite was stable between 40 and 100 MPa, or a depth of 1.8-4.4 km. These results suggest that pre-eruptive storage and crystal growth of the rhyolite were shallow; if the rhyolite ascended from greater depths, it did so slowly enough for unzoned phenocrysts to grow as it passed through the shallow crust.

  11. The impact of dissolved fluorine on bubble nucleation in hydrous rhyolite melts

    NASA Astrophysics Data System (ADS)

    Gardner, James E.; Hajimirza, Sahand; Webster, James D.; Gonnermann, Helge M.

    2018-04-01

    Surface tension of hydrous rhyolitic melt is high enough that large degrees of supersaturation are needed to homogeneously nucleate H2O bubbles during eruptive magma ascent. This study examines whether dissolved fluorine lowers surface tension of hydrous rhyolite, and thus lowers the supersaturation required for bubble nucleation. Fluorine was targeted because it, like H2O, changes melt properties and is highly soluble, unlike all other common magmatic volatiles. Rhyolite melts were saturated at Ps = 245 MPa with H2O fluid that contained F, generating rhyolite with 6.7 ± 0.4 wt.% H2O and 1.1-1.3 wt.% F. When these melts were decompressed rapidly to Pf = 149-202 MPa and quenched after 60 s, bubbles nucleated at supersaturations of ΔP = Ps - Pf ≥52 MPa, and reached bubble number densities of NB = 1012-13 m-3 at ΔP = 78-101 MPa. In comparison, rhyolite saturated with 6.34 ± 0.09 wt.% H2O, but only 0.25 wt.% F, did not nucleate bubbles until ΔP ≥ 100-116 MPa, and even then, at significantly lower NB (<1010 m-3). Numerical modeling of bubble nucleation and growth was used to estimate the values of surface tension required to generate the observed values of NB. Slight differences in melt compositions (i.e., alkalinity and H2O content), H2O diffusivity, or melt viscosity cannot explain the observed differences in NB. Instead, surface tension of F-rich rhyolite must be lower by approximately 4% than that of F-poor rhyolite. This difference in surface tension is significant and, for example, exceeds that found between hydrous basaltic andesite and hydrous rhyolite. These results suggest that is likely that surface tension for F-rich magmas, such as topaz rhyolite, is significantly lower than for F-poor magmas.

  12. Large Volume 18O-depleted Rhyolitic Volcanism: the Bruneau-Jarbidge Volcanic Field, Idaho

    NASA Astrophysics Data System (ADS)

    Boroughs, S.; Wolff, J.; Bonnichsen, B.; Godchaux, M. M.; Larson, P. B.

    2003-12-01

    The Bruneau-Jarbidge (BJ) volcanic field is located in southern Idaho at the intersection of the western and eastern arms of the Snake River Plain. The BJ region is an oval structural basin of about 6000 km2, and is likely a system of nested caldera and collapse structures similar to, though larger than, the Yellowstone Volcanic Plateau. BJ rocks are high-temperature rhyolite tuffs, high-temperature rhyolite lavas, and volumetrically minor basalts. Exposed volumes of individual rhyolite units range up to greater than 500 km3. We have analyzed feldspar and, where present, quartz from 30 rhyolite units emplaced throughout the history of the BJ center. All, including the Cougar Point Tuff, are 18O depleted (δ 18OFSP = -1.3 to 3.7‰ ), while petrographically, temporally, and chemically similar lavas erupted along the nearby Owyhee Front have "normal" rhyolite magmatic δ 18O values of 7 - 9‰ . There is no evidence for significant modification of δ 18O values by post-eruptive alteration. No correlation exists between δ 18O and age, magmatic temperature, major element composition or trace element abundances among depleted BJ rhyolites. The BJ and WSRP rhyolites possess the geochemical characteristics (depressed Al, Ca, Eu, and Sr contents, high Ga/Al and K/Na) expected of liquids derived from shallow melting of calc-alkaline granitoids with residual plagioclase and orthopyroxene (Patino-Douce, Geology v.25 p.743-746, 1997). The classic Yellowstone low δ 18O rhyolites are post-caldera collapse lavas, but at BJ, both lavas and caldera-forming ignimbrites are strongly 18O-depleted. The total volume of low δ 18O rhyolite may be as high as 10,000 km3, requiring massive involvement of meteoric-hydrothermally altered crust in rhyolite petrogenesis. Regional hydrothermal modification of the crust under the thermal influence of the Yellowstone hotspot apparently preceded voluminous rhyolite generation at Bruneau-Jarbidge.

  13. Short-circuiting magma differentiation from basalt straight to rhyolite?

    NASA Astrophysics Data System (ADS)

    Ruprecht, P.; Winslow, H.

    2017-12-01

    Silicic magmas are the product of varying degrees of crystal fractionation and crustal assimilation/melting. Both processes lead to differentiation that is step-wise rather than continuous for example during melt separation from a crystal mush (Dufek and Bachmann, 2010). However, differentiation is rarely efficient enough to evolve directly from a basaltic to a rhyolitic magma. At Volcán Puyehue-Cordón Caulle, Chile, the magma series is dominated by crystal fractionation where mixing trends between primitive and felsic end members in the bulk rock compositions are almost absent (e.g. P, FeO, TiO2 vs. SiO2). How effective fraction is in this magmatic system is not well-known. The 2011-12 eruption at Cordón Caulle provides new constraints that rhyolitic melts may be derived directly from a basaltic mush. Minor, but ubiquitous mafic, crystal-rich enclaves co-erupted with the predominantly rhyolitic near-aphyric magma. These enclaves are among the most primitive compositions erupted at Puyehue-Cordón Caulle and geochemically resemble closely basaltic magmas that are >10 ka old (Singer et al. 2008) and that have been identified as a parental tholeiitic mantle-derived magma (Schmidt and Jagoutz, 2017) for the Southern Andean Volcanic Zone. The vesiculated nature, the presence of a microlite-rich groundmass, and a lack of a Eu anomaly in these encalves suggest that they represent recharge magma/mush rather than sub-solidus cumulates and therefore have potentially a direct petrogenetic link to the erupted rhyolites. Our results indicate that under some conditions crystal fractionation can be very effective and the presence of rhyolitic magmas does not require an extensive polybaric plumbing system. Instead, primitive mantle-derived magmas source directly evolved magmas. In the case, of the magma system beneath Puyehue-Cordón Caulle, which had three historic rhyolitic eruptions (1921-22, 1960, 2011-12) these results raise the question whether rhyolite magma extraction

  14. Diversity and Petrogenesis of <4.4 Ma Rhyolites from the Izu Bonin Rear-Arc

    NASA Astrophysics Data System (ADS)

    Heywood, L. J.; DeBari, S. M.; Schindlbeck, J. C.; Escobar-Burciaga, R. D.; Gill, J.

    2016-12-01

    The Izu Bonin subduction zone has a history of abundant rhyolite production that is relevant to the development of intermediate to silicic middle crust. This study presents major and trace elemental compositions (via electron microprobe and LA-ICP-MS) of unaltered volcanic glass and phenocrysts from select medium- to high-K tephra intervals from IODP Site 1437 (Expedition 350, Izu Bonin Rear Arc). These data provide a time-resolved record of regional explosive magmatism ( 4.4Ma to present). Tephra from Site 1437 is basaltic to rhyolitic glass with accompanying phenocrysts, including hornblende. Glass compositions form a medium-K magmatic series with LREE enrichment (LaN/YbN = 2.5-6) whose trace element ratios and isotopic compositions are distinct from magmas with similar SiO2 contents in the main Izu Bonin volcanic front. Other workers have shown progressive enrichment in K and other trace element ratios moving from volcanic front westwards through the extensional region to the western seamounts in the rear arc. The <4.4 Ma rear-arc rhyolites from Site 1437 show pronounced negative Eu anomalies, high LaN/SmN (2-3.5), Ba/La <25 and Th of 1.5-4 ppm. These rhyolites show the highest variability for a given SiO2 content among all rear-arc magmas (rhyolites have 1.5-3.5 wt% K2O, Zr/Y of 1-8, LaN of 5-9 ppm) consistent with variability in literature reports of other rhyolite samples dredged from surrounding seamounts. Rhyolites have been dredged from several nearby seamounts with other high-K rhyolites dredged as close as nearby Meireki Seamount ( 3.8 Ma) and further afield in the Genroku seamount chain ( 1.88 Ma), which we compare to Site 1437 rhyolites. An extremely low-K rhyolite sill (13.6 Ma) was drilled lower in the section at Site U1437, suggesting that the mechanism for producing rhyolites in the Western Seamounts region changed over time. Rhyolites are either produced by differentiation of mafic magmas, by melting of pre-existing arc crust (as hypothesized in

  15. Dynamics of Conduit Flow and Fragmentation of Trachytic Versus Rhyolitic Eruptions

    NASA Astrophysics Data System (ADS)

    Papale, P.; Giordano, D.; del Seppia, D.; Romano, C.; Dingwell, D. B.

    We have performed a systematic investigation of the dynamics of ascent and fragmen- tation of trachitic magmas from Phlegrean Fields, and have compared such dynamics with those of the more common and more thoroughly investigated rhyolitic eruptions. The investigation involved experimental as well as numerical studies. Knowledge of the viscosity of trachytic magmas is crucial, since viscosity is one of the most im- portant controlling factors in magma ascent dynamics. We have performed a series of measurements of the dry and hydrous viscosity of trachytic liquids representative of the glassy portion of pumice from the Campanian Ignimbrite, Agnano Monte Spina, and Monte Nuovo eruptions of Phlegrean Fields, spanning a time interval from 36,000 BP to 1538 AD, and an intensity range of about 4 orders of magnitude. The results show that for water contents larger than 1-2 wt% trachytic viscosities are within one order of magnitude less than rhyolitic viscosities. On the contrary, the calculated sol- ubility of water in trachytic liquids is significantly higher than in rhyolitic liquids. We have simulated the steady, multiphase flow of gas and liquid magma, or pyro- clasts above fragmentation, for trachytic and rhyolitic compositions, by parameteris- ing quantities like the total water content and the conduit size. All else being equal, the higher water solubility of trachytes and substantially similar liquid viscosity with respect to rhyolites yields a lower mixture viscosity and lower pressure gradient in the deep conduit region for the former magma type. This results in the achievement of fragmentation conditions, calculated as the condition at which the strain rate in magma becomes too large to be supported by viscous flow, which are hundreds to thousands of meters higher in the conduit for trachytes than for rhyolites. The fragmentation vesic- ularity of trachytes is also systematically larger than that of rhyolites, still remaining in the 0.6 U 0.85 range which is

  16. The Chaitén rhyolite lava dome: Eruption sequence, lava dome volumes, rapid effusion rates and source of the rhyolite magma

    USGS Publications Warehouse

    Pallister, John S.; Diefenbach, Angela K.; Burton, William C.; Munoz, Jorge; Griswold, Julia P.; Lara, Luis E.; Lowenstern, Jacob B.; Valenzuela, Carolina E.

    2013-01-01

    We use geologic field mapping and sampling, photogrammetric analysis of oblique aerial photographs, and digital elevation models to document the 2008-2009 eruptive sequence at Chaitén Volcano and to estimate volumes and effusion rates for the lava dome. We also present geochemical and petrologic data that contribute to understanding the source of the rhyolite and its unusually rapid effusion rates. The eruption consisted of five major phases: 1. An explosive phase (1-11 May 2008); 2. A transitional phase (11-31 May 2008) in which low-altitude tephra columns and simultaneous lava extrusion took place; 3. An exogenous lava flow phase (June-September 2008); 4. A spine extrusion and endogenous growth phase (October 2008-February 2009); and 5. A mainly endogenous growth phase that began after the collapse of a prominent Peléean spine on 19 February 2009 and continued until the end of the eruption (late 2009 or possibly earliest 2010). The 2008-2009 rhyolite lava dome has a total volume of approximately 0.8 km3. The effusion rate averaged 66 m3s-1 during the first two weeks and averaged 45 m3s-1 for the first four months of the eruption, during which 0.5 km3 of rhyolite lava was erupted. These are among the highest rates measured world-wide for historical eruptions of silicic lava. Chaitén’s 2008-2009 lava is phenocryst-poor obsidian and microcrystalline rhyolite with 75.3±0.3% SiO2. The lava was erupted at relatively high temperature and is remarkably similar in composition and petrography to Chaitén’s pre-historic rhyolite. The rhyolite’s normative composition plots close to that of low pressure (100-200 MPa) minimum melts in the granite system, consistent with estimates of approximately 5 to 10 km source depths based on phase equilibria and geodetic studies. Calcic plagioclase, magnesian orthopyroxene and aluminous amphibole among the sparse phenocrysts suggest derivation of the rhyolite by melt extraction from a more mafic magmatic mush. High temperature

  17. Late Cenzoic rhyolites from the Kern Plateau, southern Sierra Nevada, California.

    USGS Publications Warehouse

    Bacon, C.R.; Duffield, W.A.

    1981-01-01

    Four late Cenozoic rhyolite domes lie atop the Kern Plateau, 30 to 40km S-SE of Mount Whitney. K-Ar and 40Ar/39Ar dating shows that Monache, Templeton, and Little Templeton Mountains are all about 2.4Ma old; a small dome nearby is approx 0.2Ma old. The three older rhyolites have SiO2 = 73-74% and have steep, fractionated rare earth element (REE) patterns; the youngest has SiO2 = 76% and a concave-upward REE pattern with a large negative Eu anomaly, Monache rhyolite contains the unusual phenocryst assemblage almandine + fayalite + biotite + oligoclase. The 2.4Ma old rocks may be nearly unmodified partial melts of crustal sources, whereas the 0.2Ma old rhyolite may be a product of relatively shallow differentiation. The rhyolites and nearby basalts are coeval with mafic and silicic volcanic rocks in the Coso Range about 40km to the SE. Their generation and eruption may reflect intense tectonic extension at the margin of the Basin and Range province and concomitant relaxation of compressive stress in a W- NW direction, allowing melts to reach the surface in the adjacent Sierra Nevada.-Authors

  18. Hydration rind dates rhyolite flows

    USGS Publications Warehouse

    Friedman, I.

    1968-01-01

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago.

  19. Hydration rind dates rhyolite flows.

    PubMed

    Friedman, I

    1968-02-23

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago.

  20. Acigöl rhyolite field, central Anatolia (part II): geochemical and isotopic (Sr-Nd-Pb, δ18O) constraints on volcanism involving two high-silica rhyolite suites

    NASA Astrophysics Data System (ADS)

    Siebel, W.; Schmitt, A. K.; Kiemele, E.; Danišík, M.; Aydin, F.

    2011-12-01

    The Acigöl rhyolite field erupted the most recent high-silica rhyolites within the Cappadocian Volcanic Province of central Anatolia, Turkey. It comprises two sequences of domes and pyroclastic rocks with eruption ages of ~150-200 ka (eastern group) and ~20-25 ka (western group). Compositionally, the eastern rhyolite group lavas are less evolved (SiO2 = 74-76 wt%), whereas the western group has higher silica abundance (SiO2 = ~77 wt%) with extremely depleted feldspar-compatible trace elements. Within each group, compositional variability is small and 143Nd/144Nd (0.51257-0.51265) and Pb isotope compositions (206Pb/204Pb = 18.87-18.88, 207Pb/204Pb = 15.65-15.67 and 208Pb/204Pb = 38.94-38.98) are homogeneous. The western group rhyolites have δ18O(zircon) overlapping mantle values (5.7 ± 0.2‰), whereas eastern group rhyolites are enriched in δ18O by ~0.5‰, consistent with a tendency to lower ɛNd values. By contrast, western group rhyolites have markedly more radiogenic 87Sr/86Sr ratios (0.7065-0.7091) compared to those of the eastern group (0.7059-0.7065). The presence of angular granitic xenoliths and a correlation between hydration (based on loss on ignition data) and 87Sr/86Sr in the western lavas, however, indicates that Sr was added during the eruption or post-eruption alteration. Isotope constraints preclude the possibility that the rhyolite magmas formed by partial melting of any known regional crystalline basement rocks. Basalts and andesites erupted in the periphery of the Acigöl field are characterised by 87Sr/86Sr ratios between 0.7040 and 0.7053, 143Nd/144Nd = 0.51259-0.51300, 206Pb/204Pb = 18.85-18.87, 207Pb/204Pb = 15.646-15.655, 208Pb/204Pb = 38.90-38.97. The isotopic and trace element data favour an origin of the rhyolites by mixing of basaltic/andesitic magmas with minor amounts of crustal melts and followed by extensive fractional crystallization.

  1. Taylor Curtis | NREL

    Science.gov Websites

    , The Environmental Law Institute, Washington, D.C. (2014) Featured Publication Curtis, Taylor L., Aaron . Golden, CO: National Renewable Energy Laboratory. NREL/TP-6A20-70098. Levine, Aaron. Taylor L. Curtis . Golden, CO: National Renewable Energy Laboratory: NREL/TP-6A20-70121. Kevin B. Jones, Curtis, Taylor L

  2. Zircon U-Pb Age Distributions in Cogenetic Crystal-Rich Dacitic and Crystal-Poor Rhyolitic Members of Zoned Ignimbrites in the Southern Rocky Mountains by Chemical Abrasion Inductively-Coupled-Plasma Mass Spectrometry (CA-LA-ICP-MS).

    NASA Astrophysics Data System (ADS)

    Sliwinski, J.; Zimmerer, M. J.; Guillong, M.; Bachmann, O.; Lipman, P. W.

    2015-12-01

    The San Juan locus of the Southern Rocky Mountain Volcanic Field (SRMVF) in SW Colorado represents an erosional remnant of a mid-Tertiary (~37-23 Ma) ignimbrite flare up that produced some of the most voluminous ignimbrites on Earth. A key feature of many SRMVF ignimbrites is compositional zonation, with many volcanic units comprising both dacitic and rhyolitic horizons. Geochemical, field and petrographic evidence suggests that dacites and rhyolites are cogenetic. Here, we report U-Pb zircon ages by chemical abrasion inductively-coupled-plasma mass spectrometry (CA-LA-ICPMS) for rhyolitic and dacitic components in four units: the Bonanza, Rat Creek, Carpenter Ridge and Nelson Mountain Tuffs. All units show zircon age spectra that are either within analytical uncertainty of Ar/Ar ages or are appreciably older, indicating prolonged magma residence times (~500 ka) prior to eruption. Anomalously young Pb-loss zones in zircon have been largely removed by chemical abrasion. Older, inherited zircons and zircon cores (60-2000 Ma) are rare in all samples, suggesting limited assimilation of upper crustal Precambrian country rock or complete resorption during recharge events and magma chamber growth.

  3. Indian Creek uranium prospects, Beaver County, Utah

    USGS Publications Warehouse

    Wyant, Donald G.; Stugard, Frederick

    1951-01-01

    The secondary uranium minerals metatorbernite (?) and autunite (?) were discovered at Indian Creek in the spring of 1950. The deposits, in sec. 26, T. 27 S., R. 6 T., Beaver County, Utah, are 20 miles west of Marysvale, and about three-eighths of a mile east of a quartz monzonite stock. The uranium minerals are sparsely disseminated in argillized and silicified earlier Tertiary Bullion Canyon latite and related volcanic rock beneart, but close to, the contact of the overlying later Tertiary Mount Belknap gray rhyolite. The prospects are in a landslide area where exposures are scarce. Therefore, trend and possible continuity of the altered and the uraniferous zones cannot be established definitely. The occurrence of secondary uranium minerals in beidellite-montmorillonite rock, formed by alteration of earlier Tertiary rocks near a quartz monzonite stock, is similar to that in some of the deposits in the Marysvale uranium district.

  4. Ancient and modern rhyolite: Using zircon trace element compositions to examine the origin of volcanic rocks

    NASA Astrophysics Data System (ADS)

    Klemetti, E. W.; Lackey, J.; Starnes, J.; Wooden, J. L.

    2011-12-01

    Volcanic rocks are an important marker for magmatism in the Earth's past and may be all that remains (or is exposed) to elucidate on magmagenesis in ancient terranes. Unlike plutonic rocks, which are likely aggregates of many pulses of magmatism over 104 to 106 year timescales, volcanic rocks are snapshots into specific moments in the development of a magmatic system, and in a larger sense, the tectonic setting in which the volcanoes reside. However, volcanic rocks from the rock record are commonly altered, preventing straightforward petrogenetic interpretation. In contrast, studies of refractory trace minerals such as zircon allow original petrogenesis to be recovered. In the south central Sierra Nevada batholith, Triassic to Cretaceous meta-rhyolites of the Mineral King roof pendant record snapshots of rhyolitic volcanism from key intervals of magmatism in the Sierra arc, however these rhyolites are highly altered and deformed, so little can be deduced about the original magmas or their tectonic settings. To resolve this, we recovered zircon from the four principle rhyolite units to date via SHRIMP-RG. Ages on rhyolites at Mineral King range from ˜196 Ma to 134 Ma, with three of the rhyolites being between 134 and 136 Ma. We also measured trace element composition (REE, Hf, Y and others) to explore the origins of the rhyolites. We can examine the processes at work in the development of these rhyolites along the western margin of North America during the Jurassic and Cretaceous by comparing them with modern volcanic arcs that produce abundant rhyolite eruptions, such as the Okataina Caldera Complex, New Zealand. Compared to zircon from the Okataina rhyolites, Mineral King rhyolites show a much more fractionation-dominated pattern of high Eu/Eu* (0.30-0.50) to low (<0.10) Eu/Eu* relative to increasing Hf, suggesting systems dominated by crystal fractionation or derived from a feldspar-rich source, unlike Okataina zircon that suggest abundance crystal recycling

  5. Similarities in basalt and rhyolite lava flow emplacement processes

    NASA Astrophysics Data System (ADS)

    Magnall, Nathan; James, Mike; Tuffen, Hugh; Vye-Brown, Charlotte

    2016-04-01

    Here we use field observations of rhyolite and basalt lava flows to show similarities in flow processes that span compositionally diverse lava flows. The eruption, and subsequent emplacement, of rhyolite lava flows is currently poorly understood due to the infrequency with which rhyolite eruptions occur. In contrast, the emplacement of basaltic lava flows are much better understood due to very frequent eruptions at locations such as Mt Etna and Hawaii. The 2011-2012 eruption of Cordón Caulle in Chile enabled the first scientific observations of the emplacement of an extensive rhyolite lava flow. The 30 to 100 m thick flow infilled a topographic depression with a negligible slope angle (0 - 7°). The flow split into two main channels; the southern flow advanced 4 km while the northern flow advanced 3 km before stalling. Once the flow stalled the channels inflated and secondary flows or breakouts formed from the flow front and margins. This cooling rather than volume-limited flow behaviour is common in basaltic lava flows but had never been observed in rhyolite lava flows. We draw on fieldwork conducted at Cordón Caulle and at Mt Etna to compare the emplacement of rhyolite and basaltic flows. The fieldwork identified emplacement features that are present in both lavas, such as inflation, breakouts from the flow font and margins, and squeeze-ups on the flow surfaces. In the case of Cordón Caulle, upon extrusion of a breakout it inflates due to a combination of continued lava supply and vesicle growth. This growth leads to fracturing and breakup of the breakout surface, and in some cases a large central fracture tens of metres deep forms. In contrast, breakouts from basaltic lava flows have a greater range of morphologies depending on the properties of the material in the flows core. In the case of Mt Etna, a range of breakout morphologies are observed including: toothpaste breakouts, flows topped with bladed lava as well as breakouts of pahoehoe or a'a lava. This

  6. Rhyolite genesis at the Picabo Volcanic Center of the Snake River Plain: Progressive recycling of hydrothermally altered rhyolites revealed by high resolution analysis of individual zircons

    NASA Astrophysics Data System (ADS)

    Drew, D.; Bindeman, I. N.; Watts, K. E.; Schmitt, A. K.; McCurry, M. O.

    2012-12-01

    The Picabo eruptive center of the Snake River Plain (SRP) produced a series of normal and low δ18O rhyolites from 10.44 Ma to 6.62 Ma, providing the first evidence of progressive recycling of hydrothermally altered rhyolites during the formation of a caldera complex. In this study we present a characterization of ignimbrites and associated lavas based on U-Pb ages and δ18O compositions of individual zircon cores measured by ion microprobe, phenocryst δ18O values measured by laser fluorination, whole rock 87Sr/86Sr and 143Nd/144Nd compositions, and whole rock geochemistry. Our data define rhyolite genesis at the Picabo volcanic center through time and have implications for the transition between volcanic centers. Caldera complex evolution at Picabo began with eruption of the 10.44 ± 0.27 Ma Tuff of Arbon Valley (TAV), a chemically zoned unit with a normal δ18Omelt value (8.15‰), very high 87Sr/86Sr (up to 0.734430) and very low ɛNd (-18). Eruptions continued with the ~9.1 Ma Two-and-a-Half-Mile Rhyolite (Kellogg et al., 1988), a unit significant in that it has an even lower ɛNd than the TAV and a normal δ18Omelt value (8.10‰). This low ɛNd of -23, of the Two-and-a-Half-Mile Rhyolite, reveals that greater than 40% of Archean crust was assimilated. These normal δ18O eruptions were followed by a series of lower δ18O eruptions distinguishable by Sr and Nd isotopes and whole rock chemistry. The 8.25 ± 0.26 Ma Rhyolite of West Pocatello has the lowest δ18Omelt value (3.34‰) of these eruptions, and based on nearly identical age, 87Sr/86Sr, 143Nd/144Nd, and whole rock chemistry, we correlate it to a 1,000 m thick intracaldera tuff (present in the INEL drillcore). Along with a distinct decrease in δ18O, from the TAV to the Rhyolite of West Pocatello, there is a corresponding increase in δ18Ozircon heterogeneity from the TAV (1‰ variation) to the low δ18O units with the greatest δ18Ozircon diversity (up to 5‰). Although morphological evidence for

  7. Degassing during magma ascent in the Mule Creek vent (USA)

    NASA Astrophysics Data System (ADS)

    Stasiuk, Mark V.; Barclay, Jenni; Carroll, Michael R.; Jaupart, Claude; Ratté, James C.; Sparks, R. Stephen J.; Tait, Stephen R.

    1996-09-01

    The structures and textures of the rhyolite in the Mule Creek vent (New Mexico, USA) indicate mechanisms by which volatiles escape from silicic magma during eruption. The vent outcrop is a 300-m-high canyon wall comprising a section through the top of a feeder conduit, vent and the base of an extrusive lava dome. Field relations show that eruption began with an explosive phase and ended with lava extrusion. Analyses of glass inclusions in quartz phenocrysts from the lava indicate that the magma had a pre-eruptive dissolved water content of 2.5 3.0 wt% and, during eruption, the magma would have been water-saturated over the vertical extent of the present outcrop. However, the vesicularity of the rhyolite is substantially lower than that predicted from closed-system models of vesiculation under equilibrium conditions. At a given elevation in the vent, the volume fraction of primary vesicles in the rhyolite increases from zero close to the vent margin to values of 20 40 vol.% in the central part. In the centre the vesicularity increases upward from approximately 20 vol.% at 300 m below the canyon rim to approximately 40 vol.% at 200 m, above which it shows little increase. To account for the discrepancy between observed vesicularity and measured water content, we conclude that gas escaped during ascent, probably beginning at depths greater than exposed, by flow through the vesicular magma. Gas escape was most efficient near the vent margin, and we postulate that this is due both to the slow ascent of magma there, giving the most time for gas to escape, and to shear, favouring bubble coalescence. Such shear-related permeability in erupting magma is supported by the preserved distribution of textures and vesicularity in the rhyolite: Vesicles are flattened and overlapping near the dense margins and become progressively more isolated and less deformed toward the porous centre. Local zones have textures which suggest the coalescence of bubbles to form permeable

  8. Degassing during magma ascent in the Mule Creek vent (USA)

    USGS Publications Warehouse

    Stasiuk, M.V.; Barclay, J.; Carroll, M.R.; Jaupart, Claude; Ratte, J.C.; Sparks, R.S.J.; Tait, S.R.

    1996-01-01

    The structures and textures of the rhyolite in the Mule Creek vent (New Mexico, USA) indicate mechanisms by which volatiles escape from silicic magma during eruption. The vent outcrop is a 300-m-high canyon wall comprising a section through the top of a feeder conduit, vent and the base of an extrusive lava dome. Field relations show that eruption began with an explosive phase and ended with lava extrusion. Analyses of glass inclusions in quartz phenocrysts from the lava indicate that the magma had a pre-eruptive dissolved water content of 2.5-3.0 wt% and, during eruption, the magma would have been water-saturated over the vertical extent of the present outcrop. However, the vesicularity of the rhyolite is substantially lower than that predicted from closed-system models of vesiculation under equilibrium conditions. At a given elevation in the vent, the volume fraction of primary vesicles in the rhyolite increases from zero close to the vent margin to values of 20-40 vol.% in the central part. In the centre the vesicularity increases upward from approximately 20 vol.% at 300 m below the canyon rim to approximately 40 vol.% at 200 m, above which it shows little increase. To account for the discrepancy between observed vesicularity and measured water content, we conclude that gas escaped during ascent, probably beginning at depths greater than exposed, by flow through the vesicular magma. Gas escape was most efficient near the vent margin, and we postulate that this is due both to the slow ascent of magma there, giving the most time for gas to escape, and to shear, favouring bubble coalescence. Such shear-related permeability in erupting magma is supported by the preserved distribution of textures and vesicularity in the rhyolite: Vesicles are flattened and overlapping near the dense margins and become progressively more isolated and less deformed toward the porous centre. Local zones have textures which suggest the coalescence of bubbles to form permeable

  9. Highly differentiated subalkaline rhyolite from Glass Mountain, Mono County, California.

    NASA Technical Reports Server (NTRS)

    Noble, D. C.; Korringa, M. K.; Hedge, C. E.; Riddle, G. O.

    1972-01-01

    Available data on the partition of Sr between coexisting feldspar and melt phases re interpreted as an indication that a rhyolite from Glass Mountain represents about 25% of a hypothetical 'parent' magma of silicic composition having a norm ntent of 150 ppm. Available Sr and Pb isotope data on nearby Pleistocene rhyolite lavas suggest that the 'parent' magmas of volcanic rocks of the area came from mafic or ultramafic source marl.

  10. Questa baseline and pre-mining ground-water quality investigation. 14. Interpretation of ground-water geochemistry in catchments other than the Straight Creek catchment, Red River Valley, Taos County, New Mexico, 2002-2003

    USGS Publications Warehouse

    Nordstrom, D. Kirk; McCleskey, R. Blaine; Hunt, Andrew G.; Naus, Cheryl A.

    2005-01-01

    The U.S. Geological Survey, in cooperation with the New Mexico Environment Department, is investigating the pre-mining ground-water chemistry at the Molycorp molybdenum mine in the Red River Valley, New Mexico. The primary approach is to determine the processes controlling ground-water chemistry at an unmined, off-site but proximal analog. The Straight Creek catchment, chosen for this purpose, consists of the same Tertiary-age quartz-sericite-pyrite altered andesite and rhyolitic volcanics as the mine site. Straight Creek is about 5 kilometers east of the eastern boundary of the mine site. Both Straight Creek and the mine site are at approximately the same altitude, face south, and have the same climatic conditions. Thirteen wells in the proximal analog drainage catchment were sampled for ground-water chemistry. Eleven wells were installed for this study and two existing wells at the Advanced Waste-Water Treatment (AWWT) facility were included in this study. Eight wells were sampled outside the Straight Creek catchment: one each in the Hansen, Hottentot, and La Bobita debris fans, four in a well cluster in upper Capulin Canyon (three in alluvial deposits and one in bedrock), and an existing well at the U.S. Forest Service Questa Ranger Station in Red River alluvial deposits. Two surface waters from the Hansen Creek catchment and two from the Hottentot drainage catchment also were sampled for comparison to ground-water compositions. In this report, these samples are evaluated to determine if the geochemical interpretations from the Straight Creek ground-water geochemistry could be extended to other ground waters in the Red River Valley , including the mine site. Total-recoverable major cations and trace metals and dissolved major cations, selected trace metals, anions, alkalinity; and iron-redox species were determined for all surface- and ground-water samples. Rare-earth elements and low-level As, Bi, Mo, Rb, Re, Sb, Se, Te, Th, U, Tl, V, W, Y, and Zr were

  11. Oxygen isotope and trace element evidence for three-stage petrogenesis of the youngest episode (260-79 ka) of Yellowstone rhyolitic volcanism

    NASA Astrophysics Data System (ADS)

    Loewen, Matthew W.; Bindeman, Ilya N.

    2015-10-01

    We report the first high-precision δ18O analyses of glass, δ18O of minerals, and trace element concentrations in glass and minerals for the 260-79 ka Central Plateau Member (CPM) rhyolites of Yellowstone, a >350 km3 cumulative volume of lavas erupted inside of 630 ka Lava Creek Tuff (LCT) caldera. The glass analyses of these crystal-poor rhyolites provide direct characterization of the melt and its evolution through time. The δ18Oglass values are low and mostly homogeneous (4.5 ± 0.14 ‰) within and in between lavas that erupted in four different temporal episodes during 200 ka of CPM volcanism with a slight shift to lower δ18O in the youngest episode (Pitchstone Plateau). These values are lower than Yellowstone basalts (5.7-6 ‰), LCT (5.5 ‰), pre-, and extracaldera rhyolites (~7-8 ‰), but higher than the earliest 550-450 ka post-LCT rhyolites (1-2 ‰). The glass δ18O value is coupled with new clinopyroxene analyses and previously reported zircon analyses to calculate oxygen isotope equilibration temperatures. Clinopyroxene records >900 °C near-liquidus temperatures, while zircon records temperatures <850 °C similar to zircon saturation temperature estimates. Trace element concentrations in the same glass analyzed for oxygen isotopes show evidence for temporal decreases in Ti, Sr, Ba, and Eu—related to Fe-Ti oxide and sanidine (±quartz) crystallization control, while other trace elements remain similar or are enriched through time. The slight temporal increase in glass Zr concentrations may reflect similar or higher temperature magmas (via zircon saturation) through time, while previosuly reported temperature decreases (e.g., Ti-in-quartz) might reflect changing Ti concentrations with progressive melt evolution. Multiple analyses of glass across single samples and in profiles across lava flow surfaces document trace element heterogeneity with compatible behavior of all analyzed elements except Rb, Nb, and U. These new data provide evidence for a

  12. Evolution of rhyolitic magmas in the crustal magmatic system beneath the Taupo Volcanic Zone, New Zealand

    NASA Astrophysics Data System (ADS)

    Johnson, E. R.; Kamenetsky, V.; McPhie, J.; Wallace, P. J.

    2009-12-01

    The Taupo Volcanic Zone (TVZ) produces the most frequent rhyolitic eruptions on Earth. This volcanic arc is also characterized by bimodal volcanism, with eruptions of andesite (primarily in the NE and SW of the zone) and minor basalt. Here we use melt inclusions (MI) to investigate the magmatic evolution of rhyolites in the TVZ and their link to TVZ basalts. Our study focuses on recent (<50 ka) explosive rhyolitic eruptions, as well as several small-volume explosive basaltic eruptions, from the Okataina Volcanic Centre in the northern part of the TVZ. The rhyolitic melts of the TVZ are thought to be formed via fractionation of a basaltic parent plus assimilation of metasedimentary crust. Trace element data from our TVZ melt inclusions lend support to this idea, with constant ratios of incompatible trace elements (e.g., U/Th) in the TVZ basalts and rhyolites. Assuming that these elements are completely incompatible, we have calculated that the TVZ rhyolites can be produced by ~80% fractional crystallization of a basaltic parent. We have also used MI volatile contents to assess the pressures (and thus depths) in the crust of magma emplacement and differentiation. Both the TVZ rhyolites and basalts are volatile-rich. Quartz-hosted MI in the rhyolites typically contain 5.5- 7.6 wt% H2O and up to 2500 ppm Cl, and olivine-hosted MI in the basalts contain up to 4.5 wt% H2O and 1250 ppm Cl. The H2O concentrations imply crystallization pressures of at least 200-440 MPa for the rhyolites, which correspond to depths of ~8-16 km. However, the presence of rhyolitic MI with lower H2O (3.5-5 wt%) suggests that crystallization may have occurred over a wide range of pressures. Additionally, the basalts erupted in the TVZ likely crystallized at minimum pressures of 100-200 MPa. Together, this suggests that basaltic and rhyolitic melt zones occur over a wide range of depths (~4-16 km). Furthermore, the emplacement of the basaltic parent and the AFC process to create the rhyolites had

  13. Extreme U-Th disequilibrium in rift-related basalts, rhyolites and granophyric granite and the timescale of rhyolite generation, intrusion and crystallization at Alid volcanic center, Eritrea

    USGS Publications Warehouse

    Lowenstern, J. B.; Charlier, B.L.A.; Clynne, M.A.; Wooden, J.L.

    2006-01-01

    Rhyolite pumices and co-erupted granophyric (granite) xenoliths yield evidence for rapid magma generation and crystallization prior to their eruption at 15·2 ± 2·9 ka at the Alid volcanic center in the Danikil Depression, Eritrea. Whole-rock U and Th isotopic analyses show 230Th excesses up to 50% in basalts <10 000 years old from the surrounding Oss lava fields. The 15 ka rhyolites also have 30–40% 230Th excesses. Similarity in U–Th disequilibrium, and in Sr, Nd, and Pb isotopic values, implies that the rhyolites are mostly differentiated from the local basaltic magma. Given the (230Th/232Th) ratio of the young basalts, and presumably the underlying mantle, the (230Th/232Th) ratio of the rhyolites upon eruption could be generated by in situ decay in about 50 000 years. Limited (∼5%) assimilation of old crust would hasten the lowering of (230Th/232Th) and allow the process to take place in as little as 30 000 years. Final crystallization of the Alid granophyre occurred rapidly and at shallow depths at ∼20–25 ka, as confirmed by analyses of mineral separates and ion microprobe data on individual zircons. Evidently, 30 000–50 000 years were required for extraction of basalt from its mantle source region, subsequent crystallization and melt extraction to form silicic magmas, and final crystallization of the shallow intrusion. The granophyre was then ejected during eruption of the comagmatic rhyolites.

  14. Ambient Effects on Basalt and Rhyolite Lavas under Venusian, Subaerial, and Subaqueous Conditions

    NASA Technical Reports Server (NTRS)

    Bridges, Nathan T.

    1997-01-01

    Both subaerial and subaqueous environments have been used as analog settings for Venus volcanism. To assess the merits of this, the effects of ambient conditions on the physical properties of lava on Venus, the seafloor, and land on Earth are evaluated. Rhyolites on Venus and on the surface of Earth solidify before basalts do because of their lower eruption temperatures. Rhyolite crust is thinner than basalt crust at times less than about an hour, especially on Venus. At later times, rhyolite crust is thicker because of its lower latent heat relative to basalt. The high pressure on the seafloor and Venus inhibits the exsolution of volatiles in lavas. Vesicularity and bulk density are proportional, so that lavas of the same composition should be more dense on the seafloor and less dense on land. Because viscosity depends partly upon the fraction of unvesiculated water in a melt, basalts with the same initial volatile abundance will be least viscous on the seafloor and most viscous on land. Assuming the same preeruptive H2O contents, molten rhyolites on Venus will have viscosities approx. 10% that of rhyolites on land. Despite lower expected viscosities, under-water flows are more buoyant and should have heights like subaerial and Venusian lavas of the same composition and extrusive history. In cases where the influence of crust is insignificant, a volume of rhyolite will have a higher aspect ratio than the same volume of basalt, no matter what the environment. If flow rheology is dominated by the presence of strong crust, aspect ratios differ little among environments or between compositions. These analyses support a rhyolitic interpretation for the composition of Venusian festooned flows and a basaltic interpretation for the composition of Venusian steep-sided domes. Although ambient effects are significant, extrusion rate and eruption history must also be considered to explain analogous volcanic landforms on Earth and Venus.

  15. Magmatic inclusions in rhyolites, contaminated basalts, and compositional zonation beneath the Coso volcanic field, California

    USGS Publications Warehouse

    Bacon, C.R.; Metz, J.

    1984-01-01

    Basaltic lava flows and high-silica rhyolite domes form the Pleistocene part of the Coso volcanic field in southeastern California. The distribution of vents maps the areal zonation inferred for the upper parts of the Coso magmatic system. Subalkalic basalts (<50% SiO2) were erupted well away from the rhyolite field at any given time. Compositional variation among these basalts can be ascribed to crystal fractionation. Erupted volumes of these basalts decrease with increasing differentiation. Mafic lavas containing up to 58% SiO2, erupted adjacent to the rhyolite field, formed by mixing of basaltic and silicic magma. Basaltic magma interacted with crustal rocks to form other SiO2-rich mafic lavas erupted near the Sierra Nevada fault zone. Several rhyolite domes in the Coso volcanic field contain sparse andesitic inclusions (55-61% SiO2). Pillow-like forms, intricate commingling and local diffusive mixing of andesite and rhyolite at contacts, concentric vesicle distribution, and crystal morphologies indicative of undercooling show that inclusions were incorporated in their rhyolitic hosts as blobs of magma. Inclusions were probably dispersed throughout small volumes of rhyolitic magma by convective (mechanical) mixing. Inclusion magma was formed by mixing (hybridization) at the interface between basaltic and rhyolitic magmas that coexisted in vertically zoned igneous systems. Relict phenocrysts and the bulk compositions of inclusions suggest that silicic endmembers were less differentiated than erupted high-silica rhyolite. Changes in inferred endmembers of magma mixtures with time suggest that the steepness of chemical gradients near the silicic/mafic interface in the zoned reservoir may have decreased as the system matured, although a high-silica rhyolitic cap persisted. The Coso example is an extreme case of large thermal and compositional contrast between inclusion and host magmas; lesser differences between intermediate composition magmas and inclusions lead to

  16. Suppressing Taylor vortices in a Taylor-Couette flow system with free surface

    NASA Astrophysics Data System (ADS)

    Bouabdallah, A.; Oualli, H.; Mekadem, M.; Gad-El-Hak, M.

    2016-11-01

    Taylor-Couette flows have been extensively investigated due to their many industrial applications, such as catalytic reactors, electrochemistry, photochemistry, biochemistry, and polymerization. Mass transfer applications include extraction, tangential filtration, crystallization, and dialysis. A 3D study is carried out to simulate a Taylor-Couette flow with a rotating and pulsating inner cylinder. We utilize FLUENT to simulate the incompressible flow with a free surface. The study reveals that flow structuring is initiated with the development of an Ekman vortex at low Taylor number, Ta = 0 . 01 . For all encountered flow regimes, the Taylor vortices are systematically inhibited by the pulsatile motion of the inner cylinder. A spectral analysis shows that this pulsatile motion causes a rapid decay of the free surface oscillations, from a periodic wavy movement to a chaotic one, then to a fully turbulent motion. This degenerative free surface behavior is interpreted as the underlying mechanism responsible for the inhibition of the Taylor vortices.

  17. The Geology of East Butte, a Rhyolitic Volcanic Dome on the Eastern Snake River Plain, Idaho

    NASA Technical Reports Server (NTRS)

    Bretches, J. E.; King, J. S.

    1985-01-01

    East Butte is a prominent volcanic dome located on the eastern Snake River Plain. It is situated 51 km west of Idaho Fallls in the southeast corner of the Idaho National Engineering facility. East Butte rises 350 meters above the Quaternary basalt flows which encircle its 2.4 kilometer diameter base. Its maximum elevation is 2003 meters above sea level. East Butte is composed dominantly of rhyolite. Armstrong and others (1975) determined a K-Ar age of 0.6 +/- m.y. for a rhyolite sample from East Butte. Detailed geologic mapping revealed East Butte to be a single, large cumulo-dome composed dominantly of rhyolite. Major element geochemical analyses indicate that the rhyolite of East Butte is mildly peralkaline (molecular excess of Na2O and K2O over Al2O3 and compositionally homogeneous. Color variations in the East Butte rhyolite result from varying amounts of chemical and physical weathering and to the degree of devitrification that the glass in the groundmass of the rhyolite underwent.

  18. Rapid ascent of rhyolitic magma at Chaitén volcano, Chile.

    PubMed

    Castro, Jonathan M; Dingwell, Donald B

    2009-10-08

    Rhyolite magma has fuelled some of the Earth's largest explosive volcanic eruptions. Our understanding of these events is incomplete, however, owing to the previous lack of directly observed eruptions. Chaitén volcano, in Chile's northern Patagonia, erupted rhyolite magma unexpectedly and explosively on 1 May 2008 (ref. 2). Chaitén residents felt earthquakes about 24 hours before ash fell in their town and the eruption escalated into a Plinian column. Although such brief seismic forewarning of a major explosive basaltic eruption has been documented, it is unprecedented for silicic magmas. As precursory volcanic unrest relates to magma migration from the storage region to the surface, the very short pre-eruptive warning at Chaitén probably reflects very rapid magma ascent through the sub-volcanic system. Here we present petrological and experimental data that indicate that the hydrous rhyolite magma at Chaitén ascended very rapidly, with velocities of the order of one metre per second. Such rapid ascent implies a transit time from storage depths greater than five kilometres to the near surface in about four hours. This result has implications for hazard mitigation because the rapidity of ascending rhyolite means that future eruptions may provide little warning.

  19. Field-trip guide to Columbia River flood basalts, associated rhyolites, and diverse post-plume volcanism in eastern Oregon

    USGS Publications Warehouse

    Ferns, Mark L.; Streck, Martin J.; McClaughry, Jason D.

    2017-08-09

    calc-alkaline lava flows overlying the CRBG across the northern and central parts of the LOEA. The Day 2 field route migrates to southern parts of the LOEA, where rocks of the CRBG are associated in space and time with lesser known and more complex silicic volcanic stratigraphy associated with middle Miocene, large-volume, bimodal basalt-rhyolite vent complexes. Key stops will provide a broad overview of the structure and stratigraphy of the middle Miocene Mahogany Mountain caldera and middle to late Miocene calc-alkaline lavas of the Owyhee basalt. Stops on Day 3 will progress westward from the eastern margin of the LOEA, examining a transition linking the Columbia River Basalt-Yellowstone province with a northwestward-younging magmatic trend of silicic volcanism that underlies the High Lava Plains of eastern Oregon. Initial field stops on Day 3 will examine key outcrops demonstrating the intercalated nature of middle Miocene tholeiitic CRBG flood basalts, prominent ash-flow tuffs, and “Snake River-type” large-volume rhyolite lava flows exposed along the Malheur River. Subsequent stops on Day 3 will focus upon the volcanic stratigraphy northeast of the town of Burns, which includes regional middle to late Miocene ash-flow tuffs, and lava flows assigned to the Strawberry Volcanics. The return route to Portland on Day 4 traverses across the western axis of the Blue Mountains, highlighting exposures of the widespread, middle Miocene Dinner Creek Tuff and aspects of Picture Gorge Basalt flows and northwest-trending feeder dikes situated in the central part of the CRBG province.

  20. Sr, Nd, and Pb Isotopic Geochemistry of Rhyolites from the Eastern Rhodopes, Bulgaria

    NASA Astrophysics Data System (ADS)

    Ivanova, R.; Kamenov, G. D.; Yanev, Y.

    2002-12-01

    Paleogene Eastern Rhodopes Volcanic Area (ERVA) is part of a more than 2000 km long magmatic belt in SE Europe extending from the Inner Dinarids (West Bosnia-Herzegovina) to Western Anatolia (European Turkey). Volcanic activity occurred during the Late Eocene-Early Oligocene and was spatially related to extensional Paleogene shallow marine basins underlain by a high-grade metamorphic basement. The volcanism is bimodal in character, with minor mafic (basalts) and major intermediate (mainly andesites) to acid (mainly rhyolites) volcanics present in similar volumes. This work focuses on Maritsa volcanic group (36-32 Ma) located in the NE part of the ERVA, S Bulgaria. The volcanic group comprises Lozen volcano composed of dacites, rhyodacites, and rhyolites, St Marina rhyolite dome, and Sheinovets rhyolite dome-cluster located within a caldera with the same name. Measured present day 87Sr/86Sr of the rhyolites range from 0.7075 to 0.7180, however on a plot 87Rb/86Sr vs 87Sr/86Sr the data form an errorchron (MSWD=21) with 30.5 +/-3.6Ma age and 87Sr/86Sr initial equal to 0.7074. Pb isotopic compositions in all of the volcanoes show similar values ranging from 18.712 to 18.768 in 206Pb/204Pb, 15.643 to 15.687 in 207Pb/204Pb, and 38.790 to 38.922 in 208Pb/204Pb. Nd isotopes show also little variations with 143Nd/144Nd ranging from 0.51242 to 0.51249. The similarity in the isotopic compositions between the volcanoes suggests common, homogeneous magmatic source. Crustal origin of the rhyolites as a result of melting of the metamorphic basement is not plausible because the rhyolites have different Sr and Nd isotopic compositions from the gneisses in the ERVA. Sr and Nd isotopic data for the rhyolites differ also from the basalts (i.e. possible mantle melts) in the Eastern Rhodopes region. Rhyolites have higher 87Sr/86Sr and lower 143Nd/144Nd ratios compared to the basalts, thus suggesting involvement of crustal component in the magma generation, most probably the metamorphic

  1. 77 FR 42714 - Eagle Creek Hydropower, LLC, Eagle Creek Land Resources, LLC, Eagle Creek Water Resources, LLC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-20

    ... Hydropower, LLC, Eagle Creek Land Resources, LLC, Eagle Creek Water Resources, LLC; Notice of Application...: Eagle Creek Hydropower, LLC; Eagle Creek Land Resources, LLC; and Eagle Creek Water Resources, LLC. e... Contact: Robert Gates, Senior Vice President-- Operations, Eagle Creek Hydropower, LLC, Eagle Creek Water...

  2. The Puelche volcanic field: Extensive Pleistocene rhyolite lava flows in the Andes of central Chile

    USGS Publications Warehouse

    Hildreth, W.; Fierstein, J.; Godoy, E.; Drake, Robert E.; Singer, B.

    1999-01-01

    A remote volcanic field in the rugged headwaters of the Rio Puelche and Rio Invernada (35.8??S) constitutes the largest cluster of Quaternary rhyolite lava flows yet identified in the Andean Southern Volcanic Zone. The Puelche Volcanic Field belongs to an intra-arc belt of silicic magmatic centers that extends, at least, 140 km north-south and lies well east of the volcanic front but nonetheless considerably west of the intraplate extensional fields of basaltic and alkaline centers of pampean Argentina. The authors' mapping has distinguished one shallow intrusive mass of early Pleistocene biotite rhyodacite (70.5% SiO2), 11 eruptive units of mid-Pleistocene high-K biotite-rhyolite lava (71.3-75.6% SiO2), and 4 eruptive units of basaltic andesite (53.95-4.9% SiO2), the conduits of which cut some of the rhyolites. Basal contacts of the rhyolite lava flows (and subjacent pyroclastic precursors) are generally scree covered, but glacial erosion has exposed internal flow structures and lithologic zonation superbly. Thicknesses of individual rhyolite lava flows range from 75 m to 400 m. Feeders for several units are well exposed. Cliff-draping unconformities and intracanyon relationships among the 11 rhyolite units show that the eruptive sequence spanned at least one glacial episode that accentuated the local relief. Lack of ice-contact features suggests, however, that all or most eruptions took place during non-glacial intervals probably between 400 ka and 100 ka. Post-eruptive glacial erosion reduced the rhyolites to several non-contiguous remnants that altogether cover 83 km2 and represent a surviving volume of about 21 km3. Consideration of slopes, lava thicknesses, and paleotopography suggest that the original area and volume were each about three times greater. Phenocryst content of the rhyolites ranges from 1 to 12%, with plagioclase>>biotite>FeTi oxides in all units and amphibole conspicuous in the least silicic. The chemically varied basaltic andesites range from

  3. Rhyolite thermobarometry and the shallowing of the magma reservoir, Coso volcanic field, California

    USGS Publications Warehouse

    Manley, C.R.; Bacon, C.R.

    2000-01-01

    The compositionally bimodal Pleistocene Coso volcanic field is located at the western margin of the Basin and Range province ~ 60 km north of the Garlock fault. Thirty-nine nearly aphyric high-silica rhyolite domes were emplaced in the past million years: one at 1 Ma from a transient magma reservoir, one at ~ 0.6 Ma, and the rest since ~ 0.3 Ma. Over the past 0.6 My, the depth from which the rhyolites erupted has decreased and their temperatures have become slightly higher. Pre-eruptive conditions of the rhyolite magmas, calculated from phenocryst compositions using the two-oxide thermometer and the Al-in-hornblende barometer, ranged from 740??C and 270 MPa (2.7 kbar; ~ 10 km depth) for the ~ 0.6 Ma magma, to 770??C and 140 MPa (1.4 kbar; ~ 5.5 km) for the youngest (~ 0.04 Ma) magma. Results are consistent with either a single rhyolitic reservoir moving upward through the crust, or a series of successively shallower reservoirs. As the reservoir has become closer to the surface, eruptions have become both more frequent and more voluminous.

  4. Silicate melt inclusion evidence for extreme pre-eruptive enrichment and post-eruptive depletion of lithium in silicic volcanic rocks of the western United States: implications for the origin of lithium-rich brines

    USGS Publications Warehouse

    Hofstra, Albert H.; Todorov, T.I.; Mercer, C.N.; Adams, D.T.; Marsh, E.E.

    2013-01-01

    To evaluate whether anatectic and/or highly fractionated lithophile element-enriched rhyolite tuffs deposited in arid lacustrine basins lose enough lithium during eruption, lithification, and weathering to generate significant Li brine resources, pre-eruptive melt compositions, preserved in inclusions, and the magnitude of post-eruptive Li depletions, evident in host rhyolites, were documented at six sites in the western United States. Each rhyolite is a member of the bimodal basalt-rhyolite assemblage associated with extensional tectonics that produced the Basin and Range province and Rio Grande rift, an evolving pattern of closed drainage basins, and geothermal energy or mineral resources. Results from the 0.8 Ma Bishop tuff (geothermal) in California, 1.3 to 1.6 Ma Cerro Toledo and Upper Bandelier tephra (geothermal) and 27.9 Ma Taylor Creek rhyolite (Sn) in New Mexico, 21.7 Ma Spor Mountain tuff (Be, U, F) and 24.6 Ma Pine Grove tuff (Mo) in Utah, and 27.6 Ma Hideaway Park tuff (Mo) in Colorado support the following conclusions. Melt inclusions in quartz phenocrysts from rhyolite tuffs associated with hydrothermal deposits of Sn, Mo, and Be are extremely enriched in Li (1,000s of ppm); those from Spor Mountain have the highest Li abundance yet recorded (max 5,200 ppm, median 3,750 ppm). Forty-five to 98% of the Li present in pre-eruptive magma was lost to the environment from these rhyolite tuffs. The amount of Li lost from the small volumes (1–10 km3) of Li-enriched rhyolite deposited in closed basins is sufficient to produce world-class Li brine resources. After each eruption, meteoric water leaches Li from tuff, which drains into playas, where it is concentrated by evaporation. The localized occurrence of Li-enriched rhyolites may explain why brines in arid lacustrine basins seldom have economic concentrations of Li. Considering that hydrothermal deposits of Sn, Mo, Be, U, and F may indicate potential for Li brines in nearby basins, we surmise that the

  5. Taylor-Made Libraries

    ERIC Educational Resources Information Center

    Lonergan, David

    2011-01-01

    Frederick Winslow Taylor (1856-1915) was an efficiency expert whose concerns were less about avoiding worker fatigue and more about increasing profit margins by any means necessary. Taylor was devoted to finding the One Best Way to carry out a task and then training workers to do that task unvaryingly; attempts by employees to improve their own…

  6. Magnetic properties of a new obsidian source, west Antelope Creek, Grant County, New Mexico

    NASA Astrophysics Data System (ADS)

    Sternberg, R. S.; Samuels, R.; Feinberg, J. M.; Shackley, M. S.

    2013-12-01

    This work is part of a Keck Geology Consortium project on characterizing obsidian sources in New Mexico using magnetic and geochemical properties. We collected over 3,000 samples, many of which were georeferenced, from 10 obsidian sources at three locales - Mule creek, Mt. Taylor, and Valles Caldera. One of the Mule Creek sources, herein called the west Antelope Creek (wAC) source, was previously unknown. The 143 samples collected at this source covered about 1 km2, but were not individually georeferenced. We plan to characterize the magnetic and chemical properties of this source to see if it is distinguishable from other nearby sources and useful for provenancing archaeological obsidians. Initial measurements on 34 specimens from 20 samples show NRM values range from 1-80 Am2/kg, and low-field susceptibilities range from 1.2-96 x 10-8 mass specific SI units. When there were two specimens from the same sample, results were in good agreement. The measurements define a rather broad field in NRM-susceptibility space compared to other Southwestern sources examined to date, and a considerably larger field than from the nearby Antelope Creek (AC) source. The previously measured NRM and susceptibility values from AC are all in the high end on both dimensions of the wAC field, so that these fields overlap but in many cases could be distinguished.

  7. The Blacktail Creek Tuff: an analytical and experimental study of rhyolites from the Heise volcanic field, Yellowstone hotspot system

    NASA Astrophysics Data System (ADS)

    Bolte, Torsten; Holtz, Francois; Almeev, Renat; Nash, Barbara

    2015-02-01

    The magma storage conditions of the 6.62 Ma Blacktail Creek Tuff eruption, belonging to the Heise volcanic field (6.62-4.45 Ma old) of the Yellowstone hotspot system, have been investigated by combining thermobarometric and experimental approaches. The results from different geothermometers (e.g., Fe-Ti oxides, feldspar pairs, apatite and zircon solubility, and Ti in quartz) indicate a pre-eruptive temperature in the range 825-875 °C. The temperature estimated using two-pyroxene pairs varies in a range of 810-950 °C, but the pyroxenes are probably not in equilibrium with each other, and the analytical results of melt inclusion in pyroxenes indicate a complex history for clinopyroxene, which hosts two compositionally different inclusion types. One natural Blacktail Creek Tuff rock sample has been used to determine experimentally the equilibrium phase assemblages in the pressure range 100-500 MPa and a water activity range 0.1-1.0. The experiments have been performed at fluid-present conditions, with a fluid phase composed of H2O and CO2, as well as at fluid-absent conditions. The stability of the quartzo-feldspathic phases is similar in both types of experiments, but the presence of mafic minerals such as biotite and clinopyroxene is strongly dependent on the experimental approach. Possible explanations are given for this discrepancy which may have strong impacts on the choice of appropriate experimental approaches for the determination of magma storage conditions. The comparison of the composition of natural phases and of experimentally synthesized phases confirms magma storage temperatures of 845-875 °C. Melt water contents of 1.5-2.5 wt% H2O are required to reproduce the natural Blacktail Creek Tuff mineral assemblage at these temperatures. Using the Ti-in-quartz barometer and the Qz-Ab-Or proportions of natural matrix glasses, coexisting with quartz, plagioclase and sanidine, the depth of magma storage is estimated to be in a pressure range between 130 and

  8. Rhyolites in the Kimberly Drill Core, Project Hotspot: First Intracaldera Ignimbrite from the Central Snake River Plain, Idaho?

    NASA Astrophysics Data System (ADS)

    Christiansen, E. H.; McCurry, M. O.; Champion, D. E.; Bolte, T.; Holtz, F.; Knott, T.; Branney, M. J.; Shervais, J. W.

    2013-12-01

    The rhyolites on the track of the Yellowstone hotspot are the classic examples of continental hotspot volcanism and the study of surface outcrops is maturing rapidly. However, in the central part of the track, where silicic volcanism is most voluminous, compositionally distinctive, and isotopically most anomalous, study of these large magma systems has been hindered because eruptive sources are buried. The 2 km Kimberly core helps fill that gap; it penetrates through surficial basalt, deep into the rhyolitic underpinnings on the southern margin of the province. The Kimberly core is dominated by thick sections of rhyolite lava and welded ignimbrite, with basalt-sediment intercalations between 241 m and 424 m depth. We tentatively interpret the core to include a thick intracaldera tuff. Our preliminary studies suggest that there are three major rhyolite units in the core. Rhyolite 3, the uppermost unit, is a nearly 130 m thick, low-silica rhyolite lava. Rhyolite 2 is the most highly evolved with ~75% silica and distinctively resorbed quartz. Rhyolite 1 is at least 1,340 m thick (the base was not cut by the core), has no apparent flow contacts or cooling breaks, and may represent a single, thick intracaldera ignimbrite. Paleomagnetic inclinations form a curious V-shaped profile, shallowing by about 18○ between 700 and 1700 m depth. We interpret this to be the result of slower cooling of the mid-part of the thick intracaldera ignimbrite. The lower unit is a low-silica rhyolite with high concentrations of Fe2O3 and TiO2--among the highest of any known ignimbrite on the SRP. It is chemically distinct from the upper units, very homogeneous, not vertically zoned, and lacks multiple populations of phenocrysts. It somewhat resembles the regionally extensive ~10 Ma outflow tuff of Wooden Shoe Butte. However, this is one of several large, petrologically similar ignimbrites as young as 8.6 Ma exposed in the Cassia Mountains south of the hole, so further work is needed. Like

  9. The Cordón Caulle rhyolite lava flow: an exceptional case study

    NASA Astrophysics Data System (ADS)

    Magnall, N.; James, M. R.; Tuffen, H.; Schipper, C. I.; Castro, J. M.; Vye-Brown, C.; Davies, A. G.; Farquharson, J.

    2017-12-01

    Rhyolites comprise the most silica-rich lavas, and rhyolitic lava flows can reach tens of kilometres in length. Interpretations of ancient and historic rhyolite lava flows suggest protracted emplacement due to relatively slow cooling of these massive bodies and have identified late stage events such as the formation of pumice diapirs. However, our understanding of emplacement processes has long remained limited by the lack of observations from an active flow. The 2011-2012 eruption of Puyehue-Cordón Caulle in southern Chile resulted in the first scientifically observed emplacement of an extensive (0.4 km3, 5 km long), crystal-poor rhyolite lava flow and has provided an unparalleled opportunity to further our understanding of flow dynamics. Here, we summarise our work on this lava flow, which has combined satellite and field observations, microstructural characterisation of samples, and numerical modelling. Early observations showed that advance of the 40 m thick flow stalled after 150 days of eruption, due to interactions with topographic barriers and the formation of a retarding surface crust. Following this, numerous breakouts formed from the flow fronts and margins, attaining lengths of ≤2 km. Microstructural characterisation supports the model that the breakouts formed due to continued lava supply to the stalled portions of the flow front along preferential thermal pathways, coupled with late-stage vesiculation of the flow core. This led to pressure increase, inflation, and eventual rupturing of the surface crust. These breakouts have been classified into four morphological types (domed, petaloid, rubbly, and cleft split) that reflect processes of advance and inflation. Some breakouts continued to advance and form after the eruption ended, with numerical modelling and direct observations suggesting mobility of the lava years after the eruption ended. Unlike other rhyolite flows, pumice diapirs were not observed at Cordón Caulle, instead late stage volatile

  10. 77 FR 13592 - AER NY-Gen, LLC; Eagle Creek Hydro Power, LLC, Eagle Creek Water Resources, LLC, Eagle Creek Land...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ...; Eagle Creek Hydro Power, LLC, Eagle Creek Water Resources, LLC, Eagle Creek Land Resources, LLC; Notice... 24, 2012, AER NY-Gen, LLC (transferor), Eagle Creek Hydro Power, LLC, Eagle Creek Water Resources.... Cherry, Eagle Creek Hydro Power, LLC, Eagle Creek Water Resources, LLC, and Eagle Creek Land Resources...

  11. 75 FR 27332 - AER NY-Gen, LLC; Eagle Creek Hydro Power, LLC; Eagle Creek Water Resources, LLC; Eagle Creek Land...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-14

    ... 9690-106] AER NY-Gen, LLC; Eagle Creek Hydro Power, LLC; Eagle Creek Water Resources, LLC; Eagle Creek... Power, LLC, Eagle Creek Water Resources, LLC, and Eagle Creek Land Resources, LLC (transferees) filed an.... Paul Ho, Eagle Creek Hydro Power, LLC, Eagle Creek Water Resources, LLC, and Eagle Creek Land Resources...

  12. Large-volume, low-δ18O rhyolites of the central Snake River Plain, Idaho, USA

    USGS Publications Warehouse

    Boroughs, Scott; Wolff, John; Bonnichsen, Bill; Godchaux, Martha; Larson, Peter

    2005-01-01

    The Miocene Bruneau-Jarbidge and adjacent volcanic fields of the central Snake River Plain, southwest Idaho, are dominated by high-temperature rhyolitic tuffs and lavas having an aggregate volume estimated as 7000 km3. Samples from units representing at least 50% of this volume are strongly depleted in 18O, with magmatic feldspar δ18OVSMOW (Vienna standard mean ocean water) values between −1.4‰ and 3.8‰. The magnitude of the 18O depletion and the complete lack of any rhyolites with normal values (7‰–10‰) combine to suggest that assimilation or melting of a caldera block altered by near- contemporaneous hydrothermal activity is unlikely. Instead, we envisage generation of the high-temperature rhyolites by shallow melting of Idaho Batholith rocks, under the influence of the Yellowstone hotspot, affected by Eocene meteoric-hydrothermal events. The seeming worldwide scarcity of strongly 18O-depleted rhyolites may simply reflect a similar scarcity of suitable crustal protoliths.

  13. Are extrusive rhyolites produced from permeable foam eruptions?

    USGS Publications Warehouse

    Friedman, I.

    1989-01-01

    The permeable foam hypothesis is suggested by Eichelberger el al. (1986) to explain a major loss of water from rhyolithic magmas in the volcanic conduit. Evidence for the high-water content of the major portion of the magmas is herein examined and rejected. Eichelberger's hypothesis does not take into account the large (~2 orders of magnitude) viscosity change that would occur in the conduit as a result of water loss. It also requires that the permeable foam collapse and weld to form an obsidian that in thin section displays no evidence of the foam. An alternate hypothesis to explain the existence of small amounts of high water content rhyolite glasses in acid volcanoes is that rhyolite magmas are relatively dry (0.1-0.3% H2O) and that water enters the magma from the environment to produce a water-rich selvage which then is kneaded into the body of the magma. -Author

  14. Mechanisms and timescales of generating eruptible rhyolitic magmas at Yellowstone caldera from zircon and sanidine geochronology and geochemistry

    USGS Publications Warehouse

    Stelten, Mark; Cooper, Kari M.; Vazquez, Jorge A.; Calvert, Andrew T.; Glessner, Justin G

    2015-01-01

    We constrain the physical nature of the magma reservoir and the mechanisms of rhyolite generation at Yellowstone caldera via detailed characterization of zircon and sanidine crystals hosted in three rhyolites erupted during the (ca. 170 – 70 ka) Central Plateau Member eruptive episode – the most recent post-caldera magmatism at Yellowstone. We present 238U-230Th crystallization ages and trace-element compositions of the interiors and surfaces (i.e., unpolished rims) of individual zircon crystals from each rhyolite. We compare these zircon data to 238U- 230Th crystallization ages of bulk sanidine separates coupled with chemical and isotopic data from single sanidine crystals. Zircon age and trace-element data demonstrate that the magma reservoir that sourced the Central Plateau Member rhyolites was long-lived (150 – 250 kyr) and genetically related to the preceding episode of magmatism, which occurred ca. 256 ka. The interiors of most zircons in each rhyolite were inherited from unerupted material related to older stages of Central Plateau Member magmatism or the preceding late Upper Basin Member magmatism (i.e., are antecrysts). Conversely, most zircon surfaces crystallized near the time of eruption from their host liquids (i.e., are autocrystic). The repeated recycling of zircon interiors from older stages of magmatism demonstrates that sequentially erupted Central Plateau Member rhyolites are genetically related. Sanidine separates from each rhyolite yield 238U-230Th crystallization ages at or near the eruption age of their host magmas, coeval with the coexisting zircon surfaces, but are younger than the coexisting zircon interiors. Chemical and isotopic data from single sanidine crystals demonstrate that the sanidines in each rhyolite are in equilibrium with their host melts, which considered along with their near-eruption crystallization ages suggests that nearly all CPM sanidines are autocrystic. The paucity of antecrystic sanidine crystals relative to

  15. Geologic and geochemical study of tin-bearing rhyolites in the Broken Ridge area, southern Wah Wah Mountains, Utah

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duttweiler, K.A.; Griffitts, W.R.

    This study was undertaken to document the geologic, petrologic, and geochemical relationships of the tin-bearing rhyolitic lava flows and domes of the 12-m.y.-old Steamboat Mountain Formation of Thompson and Perry in the area of Broken Ridge. Early phases of volcanic activity produced a crystal-rich, topaz-bearing rhyolite flow followed by eruption of a crystal-poor rhyolite from many local centers. These geochemical characteristics are typical of other topaz-bearing rhyolites in the western United States and suggest that such rhyolites formed as highly differentiated magmas. The 23-m.y.-old Bible Spring fault zone was reactivated after emplacement of the rhyolite flows that resulted in amore » series of high-angle normal faults. Multiple hydrothermal events resulted in widespread alteration along the faults and concentration of Be, F, Sn, Nb, Mo, Cu, Zn, W, and Ba. Alteration types include silicification, argillization, and alunitization. Crystalline cassiterite and wood tin are widespread and locally abundant in heavy-mineral-concentrate samples from the Broken Ridge area. The only visible cassiterite in the rocks occurs with specular hematite in veins within the silicified topaz-bearing rhyolite, immediately adjacent to a vent breccia. Trace element anomalies of Sn, Mo, Nb, and Be in rock samples well-define the vein area. The combined geologic, geochemical, and structural data suggest that an intrusive may be at depth directly beneath Broken Ridge.« less

  16. Taylor Elected to Royal Society of London

    Science.gov Websites

    SLAC, 28 May 1997 Taylor Elected to Royal Society of London Richard Taylor, physics professor at statements must be verified by facts. Taylor will travel to London in the near future for his induction, part Isaac Newton and Michael Faraday. Taylor, a Canadian citizen, received his Ph.D. at Stanford in 1962 and

  17. Contrasting perspectives on the Lava Creek Tuff eruption, Yellowstone, from new U-Pb and 40Ar/39Ar age determinations

    NASA Astrophysics Data System (ADS)

    Wilson, Colin J. N.; Stelten, Mark E.; Lowenstern, Jacob B.

    2018-06-01

    The youngest major caldera-forming event at Yellowstone was the 630-ka eruption of the Lava Creek Tuff. The tuff as mapped consists of two major ignimbrite packages (members A and B), linked to widespread coeval fall deposits and formation of the Yellowstone Caldera. Subsequent activity included emplacement of numerous rhyolite flows and domes, and development of two structurally resurgent domes (Mallard Lake and Sour Creek) that accommodate strain due to continual uplift/subsidence cycles. Uplifted lithologies previously mapped on and adjacent to Sour Creek dome were thought to include the 2.08-Ma Huckleberry Ridge Tuff, cropping out beneath Lava Creek Tuff members A and B. Mapped outcrops of this Huckleberry Ridge Tuff material were sampled as welded ignimbrite (sample YR345) on Sour Creek dome, and at nearby Bog Creek as welded ignimbrite (YR311) underlain by an indurated lithic lag breccia containing blocks of another welded ignimbrite (YR324). Zircon near-rim U-Pb analyses from these samples yield weighted mean ages of 661 ± 13 ka (YR345: 95% confidence), 655 ± 11 ka (YR311), and 664 ± 15 ka (YR324) (combined weighted mean of 658.8 ± 6.6 ka). We also studied two samples of ignimbrite previously mapped as Huckleberry Ridge Tuff on the northeastern perimeter of the Yellowstone Caldera, 12 km ENE of Sour Creek dome. Sanidines from these samples yield 40Ar/39Ar age estimates of 634.5 ± 6.8 ka (8YC-358) and 630.9 ± 4.1 ka (8YC-359). These age data show that all these units represent previously unrecognized parts of the Lava Creek Tuff and do not have any relationship to the Huckleberry Ridge Tuff. Our observations and data imply that the Lava Creek eruption was more complex than is currently assumed, incorporating two tuff units additional to those currently mapped, and which themselves are separated by a time break sufficient for cooling and some reworking. The presence of a lag breccia suggests that a source vent lay nearby (< 3 km) for some of the tuffs

  18. Post-collisional subvolcanic rhyolites associated with the Neoproterozoic Pelotas Batholith, southern Brazil

    NASA Astrophysics Data System (ADS)

    Oliveira, Diego Skieresz de; Sommer, Carlos Augusto; Philipp, Ruy Paulo; Lima, Evandro Fernandes de; Basei, Miguel Ângelo Stipp

    2015-11-01

    Neoproterozoic volcanic and subvolcanic rhyolitic systems in southernmost Brazil are correlated with acid magmatism linked to different petrotectonic associations of the Sul-Rio-Grandense Shield. A portion of this volcanism in the Dom Feliciano Belt is associated with the Pelotas Batholith, which resulted from magmatic episodes associated with the Ediacaran post-collisional evolution of southern Brazil. Ana Dias Rhyolite is the main subvolcanic occurrence of this volcanism that took place in the Quitéria region, in the central part of Rio Grande do Sul State. The acid magmatism has been commonly associated with the most differentiated granite suite phases during the final stages of emplacement of the Pelotas Batholith. The Ana Dias Rhyolite is characterized as an intrusive body with rocks that present a porphyritic to seriated texture and a gradational variation to fine-grained equigranular rocks. New zircon U-Pb dating indicates crystallization age of 581.9 ± 1.9 Ma for the Ana Dias Rhyolite. Geochemistry data characterize the rhyolites as belonging to the alkaline series; they present a metaluminous to peraluminous character; elevated SiO2 and alkali concentrations, high FeOt/FeOt + MgO ratios and agpaitic index; and low Al2O3, CaO, and MgO contents. The Zr, Rb, Y, Nb, and Ga concentrations are moderate when compared with the relatively low Ba and Sr contents. These geochemistry characteristics are common in acid magmas with alkaline affinity. The behavior of certain trace elements and REE demonstrate enrichment in more incompatible elements, in addition to the negative anomaly of Ba, the slight enrichment in Ce relative to adjacent elements, as well as the enrichment in K2O and Rb relative to Nb, suggesting magmas derived from mantle sources enriched in incompatible elements with some crustal contamination. The chemical characteristics are similar to those of A-type granites associated with Neoproterozoic post-collision magmatism in the Sul

  19. Th-230 - U-238 series disequilibrium of the Olkaria rhyolites Gregory Rift Valley, Kenya: Petrogenesis

    NASA Technical Reports Server (NTRS)

    Black, S.; Macdonald, R.; Kelly, M.

    1993-01-01

    Positive correlations of (U-238/Th-230) versus Th show the rhyolites to be products of partial melting. Positive correlations of U and Cl and U and F show that the U enrichment in the rhyolites is associated with the halogen contents which may be related to the minor phenocryst phase fractionation. Instantaneous Th/U ratios exceed time integrated Th/U ratios providing further evidence of the hydrous nature of the Olkaria rhyolite source. Excess (U-238/Th-230) in the subduction related rocks has been associated to the preferential incorporation of uranium in slab derived fluids, but no evaluation of the size of this flux has been made. The majority of the Naivasha samples show a (U-238/Th-230) less than 1 and plot close to the subduction related samples indicating the Naivasha rhyolites may also have been influenced by fluids during their formation. In general samples with high (U-238/Th-230) ratios reflecting recent enrichment of uranium relative to thorium have high thorium contents, thereby the high (U-238/Th-230) ratios are restricted to the most incompatible element enriched magmas and, hence, are a good indication that the rhyolites were formed by partial melting. If a fluid phase had some influence on the formation of the rhyolites then the uranium and thorium may have some correlation with F and Cl contents which can be mirrored by the peralkalinity. Plots of uranium against F and Cl contents are shown. The positive correlation indicates that the uranium enrichments are associated with the halogen contents. There seems to be a greater correlation for U against Cl than F indicating that the U may be transported preferentially as Cl complexes.

  20. A compositional tipping point governing the mobilization and eruption style of rhyolitic magma

    NASA Astrophysics Data System (ADS)

    di Genova, D.; Kolzenburg, S.; Wiesmaier, S.; Dallanave, E.; Neuville, D. R.; Hess, K. U.; Dingwell, D. B.

    2017-12-01

    The most viscous volcanic melts and the largest explosive eruptions on our planet consist of calcalkaline rhyolites. These eruptions have the potential to influence global climate. The eruptive products are commonly very crystal-poor and highly degassed, yet the magma is mostly stored as crystal mushes containing small amounts of interstitial melt with elevated water content. It is unclear how magma mushes are mobilized to create large batches of eruptible crystal-free magma. Further, rhyolitic eruptions can switch repeatedly between effusive and explosive eruption styles and this transition is difficult to attribute to the rheological effects of water content or crystallinity. Here we measure the viscosity of a series of melts spanning the compositional range of the Yellowstone volcanic system and find that in a narrow compositional zone, melt viscosity increases by up to two orders of magnitude. These viscosity variations are not predicted by current viscosity models and result from melt structure reorganization, as confirmed by Raman spectroscopy. We identify a critical compositional tipping point, independently documented in the global geochemical record of rhyolites, at which rhyolitic melts fluidize or stiffen and that clearly separates effusive from explosive deposits worldwide. This correlation between melt structure, viscosity and eruptive behaviour holds despite the variable water content and other parameters, such as temperature, that are inherent in natural eruptions. Thermodynamic modelling demonstrates how the observed subtle compositional changes that result in fluidization or stiffening of the melt can be induced by crystal growth from the melt or variation in oxygen fugacity. However, the rheological effects of water and crystal content alone cannot explain the correlation between composition and eruptive style. We conclude that the composition of calcalkaline rhyolites is decisive in determining the mobilization and eruption dynamics of Earth

  1. A compositional tipping point governing the mobilization and eruption style of rhyolitic magma.

    PubMed

    Di Genova, D; Kolzenburg, S; Wiesmaier, S; Dallanave, E; Neuville, D R; Hess, K U; Dingwell, D B

    2017-12-13

    The most viscous volcanic melts and the largest explosive eruptions on our planet consist of calcalkaline rhyolites. These eruptions have the potential to influence global climate. The eruptive products are commonly very crystal-poor and highly degassed, yet the magma is mostly stored as crystal mushes containing small amounts of interstitial melt with elevated water content. It is unclear how magma mushes are mobilized to create large batches of eruptible crystal-free magma. Further, rhyolitic eruptions can switch repeatedly between effusive and explosive eruption styles and this transition is difficult to attribute to the rheological effects of water content or crystallinity. Here we measure the viscosity of a series of melts spanning the compositional range of the Yellowstone volcanic system and find that in a narrow compositional zone, melt viscosity increases by up to two orders of magnitude. These viscosity variations are not predicted by current viscosity models and result from melt structure reorganization, as confirmed by Raman spectroscopy. We identify a critical compositional tipping point, independently documented in the global geochemical record of rhyolites, at which rhyolitic melts fluidize or stiffen and that clearly separates effusive from explosive deposits worldwide. This correlation between melt structure, viscosity and eruptive behaviour holds despite the variable water content and other parameters, such as temperature, that are inherent in natural eruptions. Thermodynamic modelling demonstrates how the observed subtle compositional changes that result in fluidization or stiffening of the melt can be induced by crystal growth from the melt or variation in oxygen fugacity. However, the rheological effects of water and crystal content alone cannot explain the correlation between composition and eruptive style. We conclude that the composition of calcalkaline rhyolites is decisive in determining the mobilization and eruption dynamics of Earth

  2. Lithium deposits hosted in intracontinental rhyolite calderas

    NASA Astrophysics Data System (ADS)

    Benson, T. R.; Coble, M. A.; Mahood, G. A.

    2017-12-01

    Lithium (Li) is classified as a technology-critical element due to the increasing demand for Li-ion batteries, which have a high power density and a relatively low cost that make them optimal for energy storage in mobile electronics, the electrical power grid, and hybrid and electric vehicles. Given that many projections for Li demand exceed current economic reserves and the market is dominated by Australia and Chile, discovery of new domestic Li resources will help diversify the supply chain and keep future technology costs down. Here we show that lake sediments preserved within intracontinental rhyolite calderas have the potential to host Li deposits on par with some of the largest Li brine deposits in the world. We compare Li concentrations of rhyolite magmas formed in a variety of tectonic settings using in situ SHRIMP-RG measurements of homogenized quartz-hosted melt inclusions. Rhyolite magmas that formed within thick, felsic continental crust (e.g., Yellowstone and Hideaway Park, United States) display moderate to extreme Li enrichment (1,500 - 9,000 ppm), whereas magmas formed in thin crust or crust comprised of accreted arc terranes (e.g., Pantelleria, Italy and High Rock, Nevada) contain Li concentrations less than 500 ppm. When the Li-enriched magmas erupt to form calderas, the cauldron depression serves as an ideal catchment within which meteoric water that leached Li from intracaldera ignimbrite, nearby outflow ignimbrite, and caldera-related lavas can accumulate. Additional Li is concentrated in the system through near-neutral, low-temperature hydrothermal fluids circulated along ring fractures as remnant magma solidifies and degasses. Li-bearing hectorite and illite clays form in this alteration zone, and when preserved in the geological record, can lead to a large Li deposit like the 2 Mt Kings Valley Li deposit in the McDermitt Caldera, Nevada. Because more than 100 large Cenozoic calderas occur in the western United States that formed on eruption

  3. Characteristics of Young Rhyolites at Taupo, New Zealand: Implications for the Sub-Surface Plutonic System

    NASA Astrophysics Data System (ADS)

    Wilson, C. J.; Charlier, B. L.

    2007-12-01

    The young history of Taupo volcano captures the growth and destruction in the 26.5 ka ca. 530 km3 Oruanui eruption of a large rhyolitic magma body, together with the subsequent rejuvenation of magma sources below the volcano. Integration of field information with petrological and isotopic studies at the whole-pumice and single- crystal scales provide a picture of this history. Several important contrasts are inferred to exist between Taupo and comparably-sized, long-lived silicic foci such at Long Valley and in the Bishop Tuff. At Taupo the following are demonstrable. 1. Even in crystal-poor rhyolites like the Oruanui, many grains are inherited antecrysts or xenocrysts. The Oruanui crystal-poor rhyolite body was an open system, with influxes of crystals (plus melt) from remobilised older crystal mush, melted metasedimentary country rocks and plutonics, and crystal-poor basaltic to andesitic magmas. 2. All the Taupo rhyolites were well mixed prior to eruption, and there are no gradients in the eruption products to suggest that the holding chamber(s) were stratified to any extent. 3. Mafic magmas rose into, interacted with, and ponded on the floors of crystal-poor rhyolite in the Oruanui and Waimihia (3.5 ka) examples, again implying that the chamber floor was sharply defined, not a gradual progression down into a more crystal- rich root zone. 4. Pre-Oruanui activity involved contrasting magma types being generated simultaneously, but erupting from geographically separated vents. Post-Oruanui activity has seen (subtly) contrasting magma groups being erupted from vents in the same geographic area, but separated in time. The Oruanui and post-Oruanui magmas are different and do not appear to be related by consanguinity or by mixing - the Oruanui eruption effectively destroyed its magma body. These features are consistent with rhyolite magma generation at Taupo that is exceptionally fast, driven by high fluxes of mafic magmas into a highly heterogeneous crustal melange

  4. 40Ar/39Ar geochronology and geochemical reconnaissance of the Eocene Lowland Creek volcanic field, west-central Montana

    USGS Publications Warehouse

    Dudas, F.O.; Ispolatov, V.O.; Harlan, S.S.; Snee, L.W.

    2010-01-01

    We report geochronological and geochemical data for the calc-alkalic Lowland Creek volcanic field (LCVF) in westcentral Montana. 40Ar/ 39Ar age determinations show that the LCVF was active from 52.9 to 48.6 Ma, with tuff-forming eruptions at 52.9 ?? 0.14 and 51.8 ?? 0.14 Ma. These dates span the age range of vigorous Eocene igneous activity in the Kamloops-Absaroka-Challis belt. The LCVF evolved upward from basal rhyolites (SiO 2>71 wt%) to dacites and andesites (SiO 2 > 62 wt%). Compositional change parallels a transition from early explosive volcanism to late effusive activity. Four geochemical components can be detected in the rocks. A component with 206Pb/204Pb < 16.5 and epsilon;Nd near-15 is predominant in anhydrous, two-pyroxene dacites; hydrous rhyolites, rhyodacites, and dacites with epsilon;Nd below-10 are dominated by a second component; hydrous rocks with 206Pb/ 204Pb > 18.3 and epsilon;Nd>-9 contain a third component; and an andesite with low Nd content and epsilon;Nd near-9 probably contains a fourth component. The first three components probably derive from the lower and middle crust, whereas the fourth is probably from the lithospheric mantle. ?? 2010 by The University of Chicago.

  5. New insights into the origin of the bimodal volcanism in the middle Okinawa Trough: not a basalt-rhyolite differentiation process

    NASA Astrophysics Data System (ADS)

    Zhang, Yuxiang; Zeng, Zhigang; Chen, Shuai; Wang, Xiaoyuan; Yin, Xuebo

    2018-06-01

    In the middle Okinawa Trough (MOT), rhyolites have been typically considered as products of crystallization differentiation of basaltic magma as a feature of bimodal volcanism. However, the evidence is insufficient. This paper compared chemical trends of volcanic rocks from the MOT with fractional crystallization simulation models and experimental results and utilized trace element modeling combined with Rayleigh fractionation calculations to re-examine fractional crystallization processes in generating rhyolites. Both qualitative and quantitative studies indicate that andesites, rather than rhyolites, originate by fractional crystallization from basalts in the MOT. Furthermore, we established two batch-melting models for the MOT rhyolites and proposed that type 1 rhyolites are produced by remelting of andesites with amphiboles in the residue, while type 2 rhyolites are derived from remelting of andesites without residual amphiboles. It is difficult to produce melts with a SiO2 content ranging from 62% to 68% either by magmatic differentiation from basalts or by remelting of andesites, and this difficulty might help account for the compositional gap (Daly gap) for bimodal volcanism in the Okinawa Trough.

  6. Trace element diffusion and kinetic fractionation in wet rhyolitic melt

    NASA Astrophysics Data System (ADS)

    Holycross, Megan E.; Watson, E. Bruce

    2018-07-01

    Piston-cylinder experiments were run to determine the chemical diffusivities of 21 trace elements (Sc, V, Y, Zr, Nb, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Hf, Th and U) in hydrous rhyolitic melts at 1 GPa pressure and temperatures from 850 to 1250 °C. Diffusion couple glasses were doped with trace elements in low concentrations to characterize the diffusivities of all cations in a single experiment. Laser ablation ICP-MS was used to evaluate the trace element concentration gradients that developed in the silicate glasses. All calculated diffusion coefficients correspond to the temperature dependence D = D0exp(-Ea/RT). Rhyolite liquids contained either ∼4.1 wt% or ∼6.2 wt% dissolved H2O; separate Arrhenius relationships are produced for each melt composition. Trace element diffusivities in the melt with 6.2 wt% H2O are roughly two times higher than those in the less hydrous melt. Calculated trace element diffusion coefficients cover nearly two orders of magnitude at a given temperature. The high field strength elements are the slowest diffusers, followed by the transition metals and heavy rare earth elements. The light rare earth elements have the fastest diffusion rates in hydrous rhyolitic melt. The measured diffusion coefficients range down to values sufficiently low to preclude diffusive homogenization over geochemically realistic time scales in some cases. The substantial differences in the diffusivities of individual cations may result in fractionated trace element signatures in rhyolite melt pockets. A simple model is used to explore the potential for kinetic fractionation of REE during growth of an apatite crystal in a diffusive boundary layer locally saturated in P2O5. The faster-diffusing light REE are more efficiently transported away from the crystal interface than the slower-moving heavy REE. Diffusion effects will enrich the melt boundary layer in slow-moving HREE relative to the faster LREE. The kinetic fractionation of REE in the

  7. A First Look at Airborne Imaging Spectrometer (AIS) Data in an Area of Altered Volcanic Rocks and Carbonate Formations, Hot Creek Range, South Central Nevada

    NASA Technical Reports Server (NTRS)

    Feldman, S. C.; Taranik, J. V.; Mouat, D. A.

    1985-01-01

    Three flight lines of Airborne Imaging Spectrometer (AIS) data were collected in 128 bands between 1.2 and 2.4 microns in the Hot Creek Range, Nevada on July 25, 1984. The flight lines are underlain by hydrothermally altered and unaltered Paleozoic carbonates and Tertiary rhyolitic to latitic volcanics in the Tybo mining district. The original project objectives were to discriminate carbonate rocks from other rock types, to distinguish limestone from dolomite, and to discriminate carbonate units from each other using AIS imagery. Because of high cloud cover over the prime carbonate flight line and because of the acquisition of another flight line in altered and unaltered volcanics, the study has been extended to the discrimination of alteration products. In an area of altered and unaltered rhyolites and latites in Red Rock Canyon, altered and unaltered rock could be discriminated from each other using spectral features in the 1.16 to 2.34 micron range. The altered spectral signatures resembled montmorillonite and kaolinite. Field samples were gathered and the presence of montmorillonite was confirmed by X-ray analysis.

  8. How to fragment peralkaline rhyolites: Observations on pumice using combined multi-scale 2D and 3D imaging

    NASA Astrophysics Data System (ADS)

    Hughes, Ery C.; Neave, David A.; Dobson, Katherine J.; Withers, Philip J.; Edmonds, Marie

    2017-04-01

    Peralkaline rhyolites are volatile-rich magmas that typically erupt in continental rift settings. The high alkali and halogen content of these magmas results in viscosities two to three orders of magnitude lower than in calc-alkaline rhyolites. Unless extensive microlite crystallisation occurs, the calculated strain rates required for fragmentation are unrealistically high, yet peralkaline pumices from explosive eruptions of varying scales are commonly microlite-free. Here we present a combined 2D scanning electron microscopy and 3D X-ray microtomography study of peralkaline rhyolite vesicle textures designed to investigate fragmentation processes. Microlite-free peralkaline pumice textures from Pantelleria, Italy, strongly resemble those from calc-alkaline rhyolites on both macro and micro scales. These textures imply that the pumices fragmented in a brittle fashion and that their peralkaline chemistry had little direct effect on textural evolution during bubble nucleation and growth. We suggest that the observed pumice textures evolved in response to high decompression rates and that peralkaline rhyolite magmas can fragment when strain localisation and high bubble overpressures develop during rapid ascent.

  9. Rayleigh-Taylor mixing in supernova experiments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Swisher, N. C.; Abarzhi, S. I., E-mail: snezhana.abarzhi@gmail.com; Kuranz, C. C.

    We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced Rayleigh-Taylor instability and Rayleigh-Taylor mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of the Rayleigh-Taylor flow in supernova experiments and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By properlymore » accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are reported to describe asymptotic dynamics of Rayleigh-Taylor flow with time-dependent acceleration by applying theoretical analysis that considers symmetries and momentum transport. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments Rayleigh-Taylor flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; Rayleigh-Taylor mixing keeps order.« less

  10. Cooling and crystallization of rhyolite-obsidian lava: Insights from micron-scale projections on plagioclase microlites

    NASA Astrophysics Data System (ADS)

    Sano, Kyohei; Toramaru, Atsushi

    2017-07-01

    To reveal the cooling process of a rhyolite-obsidian flow, we studied the morphology of plagioclase microlites in the Tokachi-Ishizawa lava of Shirataki, northern Hokkaido, Japan, where the structure of the lava can be observed from obsidian at the base of the flow to the innermost rhyolite. Needle-like micron-scale textures, known as "projections", occur on the short side surfaces of the plagioclase microlites. Using FE-SEM we discovered a positive correlation between the lengths and spacings of these projections. On the basis of the instability theory of an interface between melt and crystal, and to understand the length and spacing data, we developed a model that explains the positive correlation and allows us to simultaneously estimate growth rates and growth times. Applying the model to our morphological data and the estimated growth rates and growth times, we suggest that the characteristics of the projections reflect the degree of undercooling, which in turn correlates with lava structure (the obsidian at the margin of the flow experienced a higher degree of undercooling than the interior rhyolite). The newly developed method provides insights into the degree of undercooling during the final stages of crystallization of a rhyolitic lava flow.

  11. Contrasting sources of Late Paleozoic rhyolite magma in the Polish Lowlands: evidence from U-Pb ages and Hf and O isotope composition in zircon

    NASA Astrophysics Data System (ADS)

    Słodczyk, Elżbieta; Pietranik, Anna; Glynn, Sarah; Wiedenbeck, Michael; Breitkreuz, Christoph; Dhuime, Bruno

    2018-02-01

    The Polish Lowlands, located southwest of the Teisseyre-Tornquist Zone, within Trans-European Suture Zone, were affected by bimodal, but dominantly rhyolitic, magmatism during the Late Paleozoic. Thanks to the inherited zircon they contain, these rhyolitic rocks provide a direct source of information about the pre-Permian rocks underlying the Polish Lowland. This paper presents zircon U-Pb geochronology and Hf and O isotopic results from five drill core samples representing four rhyolites and one granite. Based on the ratio of inherited vs. autocrystic zircon, the rhyolites can be divided into two groups: northern rhyolites, where autocrystic zircon is more abundant and southern rhyolites, where inherited zircon dominates. We suggest that the magma sources and the processes responsible for generating high silica magmas differ between the northern and southern rhyolites. Isotopically distinct sources were available during formation of northern rhyolites, as the Hf and O isotopes in magmatic zircon differ between the two analysed localities of northern rhyolites. A mixing between magmas formed from Baltica-derived mudstone-siltstone sediments and Avalonian basement or mantle can explain the diversity between the zircon compositions from the northern localities Daszewo and Wysoka Kamieńska. Conversely, the southern rhyolites from our two localities contain zircon with similar compositions, and these units can be further correlated with results from the North East German Basin, suggesting uniform source rocks over this larger region. Based on the ages of inherited zircon and the isotopic composition of magmatic ones, we suggest that the dominant source of the southern rhyolites is Variscan foreland sediments mixed with Baltica/Avalonia-derived sediments.

  12. Educational utilization of outstanding spherulitic rhyolite occurred in Cheongsong, Korea

    NASA Astrophysics Data System (ADS)

    Jang, Y. D.; Woo, H.

    2015-12-01

    Cheongsong is located in the central eastern area of South Korea. Unique spherulitic rhyolites occur in this region as dykes formed about 48 to 50 million years ago. Composed of quartz and feldspar these spherulitic rhyolites show various flowerlike shapes, such as chrysanthemum, dandelion, rose, carnation, sunflower, dahlia and so on, so they are called 'flower stones'. The spherulite indicates that it was undercooled caused by very fast cooling at a shallow depth near the surface and the variety of shapes resulted from the difference of crystallizing conditions. According to the condition, minerals start to crystallize homogeneously or heterogeneously and develop as rounded or fibrous shapes, representing beautiful patterns when combined. These spherulitic structures are very rare not only in Korea but also globally, being valuable for research and preservation because of their rarity, beauty and diversity. Cheongsong therefore applies to the UGG (UNESCO Global Geopark) in an attempt to popularize the flower stones and use them as education materials which can also be incorporated in other valuable sites. The exhibition center provides diverse types of flower stones in which visitors could learn about rhyolitic volcanism, crystallization and spherulite and can experience the process of changing a rough stone into a flower stone. A geotrail course has also been created, showing each type of flower stone on the outcrop and providing educational programs about geological mechanisms of the stones with a trained guide.

  13. Origin of heavy Fe isotope compositions in high-silica igneous rocks: A rhyolite perspective

    NASA Astrophysics Data System (ADS)

    Du, De-Hong; Wang, Xiao-Lei; Yang, Tao; Chen, Xin; Li, Jun-Yong; Li, Weiqiang

    2017-12-01

    The origin of heavy Fe isotope compositions in high-silica (>70 wt% SiO2) igneous rocks remains a highly controversial topic. Considering that fluid exsolution in eruptive rocks is more straight-forward to constrain than in plutonic rocks, this study addresses the problem of Fe isotope fractionation in high-silica igneous rocks by measuring Fe isotope compositions of representative rhyolitic samples from the Neoproterozoic volcanic-sedimentary basins in southern China and the Triassic Tu Le Basin in northern Vietnam. The samples show remarkably varied δ56FeIRMM014 values ranging from 0.05 ± 0.05‰ to 0.55 ± 0.05‰, which is among the highest values reported from felsic rocks. The extensional tectonic setting and short melt residence time in magma chambers for the studied rhyolites rule out Soret diffusion and thermal migration processes as causes of the high δ56Fe values. Effects of volcanic degassing and fluid exsolution on bulk rock δ56Fe values for the rhyolites are also assessed using bulk rock geochemical indicators and Rayleigh fractionation models, and these processes are found to be insufficient to produce resolvable changes in Fe isotope compositions of the residual melt. The most probable mechanism accounting for heavy Fe isotope compositions in the high-silica rhyolites is narrowed down to fractional crystallization processes in the magma before rhyolite eruption. Removal of isotopically light Fe-bearing minerals (i.e. ulvöspinel-rich titanomagnetite, ilmenite and biotite) is proposed as the main cause of Fe isotope variation in silicic melts during magmatic evolution. This study implies that crystal fractionation is the dominant mechanism that controls Fe isotope fractionation in eruptive rocks and Fe isotopes could be used to study magmatic differentiation of high-silica magmas.

  14. Drilling into Rhyolitic Magma at Shallow depth at Krafla Volcanic Complex, NE-Iceland

    NASA Astrophysics Data System (ADS)

    Mortensen, A. K.; Markússon, S. H.; Gudmundsson, Á.; Pálsson, B.

    2017-12-01

    Krafla volcanic complex in NE-Iceland is an active volcano but the latest eruption was the Krafla Fires in 1975-1984. Though recent volcanic activity has consisted of basaltic fissure eruptions, then it is rhyolitic magma that has been intercepted on at least two occasions while drilling geothermal production wells in the geothermal field suggesting a layered magma plumbing system beneath the Krafla volcanic complex. In 2008 quenched rhyolitic glass was retrieved from the bottom of well KJ-39, which is 2865 m deep ( 2571 m true vertical depth). In 2009 magma was again encountered at an even shallower depth and in more than 2,5 km distance from the bottom of well KJ-39, but in 2009 well IDDP-1 was drilled into magma three times just below 2100 m depth. Only on the last occasion was quenched glass retrieved to confirm that magma had been encountered. In well KJ-39 the quenched glass was rhyolitic in composition. The glass contained resorbed minerals of plagioclase, clinopyroxene and titanomagnetite, but the composition of the glass resembles magma that has formed by partial melting of hydrated basalt. The melt was encountered among cuttings from impermeable, coarse basaltic intrusives at a depth, where the well was anticipated to penetrate the Hólseldar volcanic fissure. In IDDP-1 the quenched glass was also rhyolitic in composition. The glass contained less than 5% of phenocrysts, but the phenocryst assemblage included andesine plagioclase, augite, pigeonite, and titanomagnetite. At IDDP-1 the melt was encountered below a permeable zone composed of fine to coarse grained felsite and granophyre. The disclosure of magma in two wells at Krafla volcanic complex verify that rhyolitic magma can be encountered at shallow depth across a larger area within the caldera. The encounter of magma at shallow depth conforms with that superheated conditions have been found at >2000 m depth in large parts of Krafla geothermal field.

  15. 33 CFR 110.79c - Fish Creek Harbor, Fish Creek, Wisconsin.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Fish Creek Harbor, Fish Creek, Wisconsin. 110.79c Section 110.79c Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.79c Fish Creek Harbor, Fish Creek...

  16. 33 CFR 110.79c - Fish Creek Harbor, Fish Creek, Wisconsin.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Fish Creek Harbor, Fish Creek, Wisconsin. 110.79c Section 110.79c Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.79c Fish Creek Harbor, Fish Creek...

  17. 33 CFR 110.79c - Fish Creek Harbor, Fish Creek, Wisconsin.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Fish Creek Harbor, Fish Creek, Wisconsin. 110.79c Section 110.79c Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.79c Fish Creek Harbor, Fish Creek...

  18. 33 CFR 110.79c - Fish Creek Harbor, Fish Creek, Wisconsin.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Fish Creek Harbor, Fish Creek, Wisconsin. 110.79c Section 110.79c Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.79c Fish Creek Harbor, Fish Creek...

  19. 33 CFR 110.79c - Fish Creek Harbor, Fish Creek, Wisconsin.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Fish Creek Harbor, Fish Creek, Wisconsin. 110.79c Section 110.79c Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.79c Fish Creek Harbor, Fish Creek...

  20. Surface and subsurface facies architecture of a small hydroexplosive, rhyolitic centre in the Mesoproterozoic Gawler Range Volcanics, South Australia

    NASA Astrophysics Data System (ADS)

    Roache, M. W.; Allen, S. R.; McPhie, J.

    2000-12-01

    At Menninnie Dam, South Australia, a drilling program has revealed a complete section through the subsurface feeder system and erupted products of a small, hydroexplosive, rhyolitic centre within the Mesoproterozoic Gawler Range Volcanics. Porphyritic rhyolite intruded near-vertical faults in the Palaeoproterozoic basement and at less than a few hundred metres depth, interacted with fault-hosted (hot?) groundwater. Hydrofracturing of the wall rock occurred in advance of and at the margins of the rhyolitic intrusions. The rhyolitic intrusions have peperitic margins and grade into discordant lithic-rich PB facies. The advancing fragmentation front intersected the palaeosurface, triggering phreatic eruptions that deposited a poorly sorted, lithic-rich explosion breccia. Rhyolite then rose to the surface through the intrusive breccias and shallow-seated magma-water interaction occurred in the conduit within <50 m of the surface. As the magma discharge rate increased, ;dry; explosive activity prevailed. A fall deposit, the top of which is welded, was deposited close to the vent, and in more distal locations (>800 m from the inferred source), the products include muddy sandstone and pumice breccia. At the end of the eruption, rhyolitic lava was extruded in the form of a small dome. The presence of contemporaneous Pb-Zn-Ag mineralisation in the wall rocks suggests that an active hydrothermal system may have been involved in the formation of the Menninnie Dam hydroexplosive volcanic centre.

  1. Dynamics of a large, restless, rhyolitic magma system at Laguna del Maule, southern Andes, Chile

    USGS Publications Warehouse

    Singer, Brad S.; Andersen, Nathan L.; Le Mével, Hélène; Feigl, Kurt L.; DeMets, Charles; Tikoff, Basil; Thurber, Clifford H.; Jicha, Brian R.; Cardonna, Carlos; Córdova, Loreto; Gil, Fernando; Unsworth, Martyn J.; Williams-Jones, Glyn; Miller, Craig W.; Fierstein, Judith; Hildreth, Edward; Vazquez, Jorge A.

    2014-01-01

    Explosive eruptions of large-volume rhyolitic magma systems are common in the geologic record and pose a major potential threat to society. Unlike other natural hazards, such as earthquakes and tsunamis, a large rhyolitic volcano may provide warning signs long before a caldera-forming eruption occurs. Yet, these signs—and what they imply about magma-crust dynamics—are not well known. This is because we have learned how these systems form, grow, and erupt mainly from the study of ash flow tuffs deposited tens to hundreds of thousands of years ago or more, or from the geophysical imaging of the unerupted portions of the reservoirs beneath the associated calderas. The Laguna del Maule Volcanic Field, Chile, includes an unusually large and recent concentration of silicic eruptions. Since 2007, the crust there has been inflating at an astonishing rate of at least 25 cm/yr. This unique opportunity to investigate the dynamics of a large rhyolitic system while magma migration, reservoir growth, and crustal deformation are actively under way is stimulating a new international collaboration. Findings thus far lead to the hypothesis that the silicic vents have tapped an extensive layer of crystal-poor, rhyolitic melt that began to form atop a magmatic mush zone that was established by ca. 20 ka with a renewed phase of rhyolite eruptions during the Holocene. Modeling of surface deformation, magnetotelluric data, and gravity changes suggest that magma is currently intruding at a depth of ~5 km. The next phase of this investigation seeks to enlarge the sets of geophysical and geochemical data and to use these observations in numerical models of system dynamics.

  2. Contrasting perspectives on the Lava Creek Tuff eruption, Yellowstone, from new U–Pb and 40Ar/39Ar age determinations

    USGS Publications Warehouse

    Wilson, Colin J. N.; Stelten, Mark; Lowenstern, Jacob B.

    2018-01-01

    The youngest major caldera-forming event at Yellowstone was the ~ 630-ka eruption of the Lava Creek Tuff. The tuff as mapped consists of two major ignimbrite packages (members A and B), linked to widespread coeval fall deposits and formation of the Yellowstone Caldera. Subsequent activity included emplacement of numerous rhyolite flows and domes, and development of two structurally resurgent domes (Mallard Lake and Sour Creek) that accommodate strain due to continual uplift/subsidence cycles. Uplifted lithologies previously mapped on and adjacent to Sour Creek dome were thought to include the ~ 2.08-Ma Huckleberry Ridge Tuff, cropping out beneath Lava Creek Tuff members A and B. Mapped outcrops of this Huckleberry Ridge Tuff material were sampled as welded ignimbrite (sample YR345) on Sour Creek dome, and at nearby Bog Creek as welded ignimbrite (YR311) underlain by an indurated lithic lag breccia containing blocks of another welded ignimbrite (YR324). Zircon near-rim U–Pb analyses from these samples yield weighted mean ages of 661 ± 13 ka (YR345: 95% confidence), 655 ± 11 ka (YR311), and 664 ± 15 ka (YR324) (combined weighted mean of 658.8 ± 6.6 ka). We also studied two samples of ignimbrite previously mapped as Huckleberry Ridge Tuff on the northeastern perimeter of the Yellowstone Caldera, ~ 12 km ENE of Sour Creek dome. Sanidines from these samples yield 40Ar/39Ar age estimates of 634.5 ± 6.8 ka (8YC-358) and 630.9 ± 4.1 ka (8YC-359). These age data show that all these units represent previously unrecognized parts of the Lava Creek Tuff and do not have any relationship to the Huckleberry Ridge Tuff. Our observations and data imply that the Lava Creek eruption was more complex than is currently assumed, incorporating two tuff units additional to those currently mapped, and which themselves are separated by a time break sufficient for cooling and some reworking. The presence of a lag breccia suggests that a source

  3. H2O-CO2-S-Cl partitioning and mixing in rhyolitic melts and fluid - Implications on closed-system degassing in rhyolite

    NASA Astrophysics Data System (ADS)

    Ding, S.; Webster, J. D.

    2017-12-01

    Magmatic degassing involving multiple volatile components (C, O, H, S, Cl, etc.) is one of the key factors influencing the timing and nature of volcanic eruptions, and the chemistry of volcanic gases released to the surface. In particular, exsolution of these volatiles from silicic magma during ascent could trigger explosive volcanic eruptions, which can exert strong impacts on surface temperature, ecology and human health. However, quantitative evaluation of this process in silicic magma remains ambiguous due to the lack of experiments in such chemically complex systems. Rhyolite-fluid(s) equilibria experiments were conducted in an IHPVat 100-300 MPa and 800 ° C to determine the solubilities, fluid-melt partitioning, and mixing properties of H2O, CO2, S, and Cl in the oxygen fugacity (fO2) range of FMQ to FMQ+3. The integrated bulk fluids contain up to 94 mol% H2O, 32 mol% CO2, 1 mol% S and 1mol% Cl. Rhyolite melt dissolved 20- 770 ppm CO2 and 4-7 wt.% H2O, varying with pressure, fluid composition, and fO2. Concentrations of H2O and CO2 in melt from C-O-H-S-Cl- bearing experiments at 100 and 200 MPa, and from C-O-H only experiments are generally consistent with the predictions of existing CO2-H2O solubility models based on the C-O-H only system [1-4], while the solubilities of H2O and CO2 in melt with addition of S±Cl at 300 MPa are less than those of the C-O-H- only system. This reduction in H2O and CO2 solubilities exceeds the effects of simple dilution of the coexisting fluid owing to addition of other volatiles, and rather, reflects complex mixing relations. Rhyolite melt also dissolved 20-150 ppm S and 850-2000 ppm Cl, varying with pressure. At 300 MPa, S concentrations in the melt change with fO2. The partitioning of CO2 and S between fluid and melt varies as a function of fluid composition and fO2. Solubilities and complex mixing relationships of CO2, H2O, S and Cl revealed in our experiments can be applied to massive rhyolitic eruptions like those of the

  4. Herringbone streaks in Taylor-Couette turbulence.

    PubMed

    Dong, S

    2008-03-01

    We study near-wall streaks that form herringbonelike patterns in Taylor-Couette turbulence and in counter-rotating Taylor-Couette turbulence through three-dimensional direct numerical simulations. The orientation, axial distribution, onset, and tilting angle of these streaks are characterized.

  5. Argon Diffusion Measured in Rhyolite Melt at 100 MPa

    NASA Astrophysics Data System (ADS)

    Weldon, N.; Edwards, P. M.; Watkins, J. M.; Lesher, C. E.

    2016-12-01

    Argon diffusivity (D_{Ar} ) controls the rate and length scale of argon exchange between melt and gas phases and is used as a parameter to model noble gas fractionation during magma degassing. D_{Ar} may also be useful in geochronology to estimate the distribution of excess (non-radiogenic) atmospheric argon in lavas. Our measurements of D_{Ar} in molten anhydrous rhyolite near 1000 °C and 100 MPa add to the existing dataset. Using a rapid-quench cold seal pressure apparatus we exposed cylindrical charges drilled from a Miocene rhyolite flow near Buck Mtn., CA to a pure argon atmosphere resulting in a gradually lengthening argon concentration gradient between the saturated surface and the argon poor interior. Argon concentration was measured by electron microprobe along radial transects from the center to the surface of bisected samples. D_{Ar} was calculated for each transect by fitting relative argon concentration (as a function of distance from the surface) to Green's function (given each experiment's specific temperature, pressure and runtime). Variability (σ = 1.202{μm }^{2} /s) was smaller than in previous studies, but still greater than what is likely due to analytical or experimental uncertainty. We observed a symmetric geometric bias in the distribution of argon in our samples, possibly related to advective redistribution of argon accompanying the deformation of cylindrical charges into spheroids driven by surface tension. Average diffusivity, D_{Ar} = 4.791{μm }^{2} /s, is close to the predicted value, D_{Ar} = {μm }^{2} /s ( σ_{ \\bar{x} } = 1.576 {μm }^{2} /s), suggesting that Behrens and Zhang's (2001) empirical model is valid for anhydrous rhyolite melts to relatively higher temperatures and lower pressures. Behrens, H. and Y. Zhang (2001). "Ar diffusion in hydrous silicic melts: implications for volatile diffusion mechanisms and fractionation." Earth and Planetary Science Letters 192: 363-376.

  6. Basement control of alkalic flood rhyolite magmatism of the Davis Mountains volcanic field, Trans-Pecos Texas, U.S.A.

    NASA Astrophysics Data System (ADS)

    Parker, Don F.; White, John C.; Ren, Minghua; Barnes, Melanie

    2017-11-01

    Voluminous silicic lava flows, erupted 37.4 Ma from widespread centers within the Davis Mountains Volcanic Field (DMVF), covered approximately 10,000 km2 with an initial volume as great as 1000 km3. Lava flows form three major stratigraphic units: the Star Mountain Rhyolite (minimum 220 km3) of the eastern Davis Mountains and adjacent Barilla Mountains, the Crossen Formation ( 75 km3) of the southern Davis Mountains, and the Bracks Rhyolite ( 75 km3) of the Rim Rock region west of the Davis Mountains proper. Similar extensive rhyolite lava also occurs in slightly younger units (Adobe Canyon Rhyolite, 125 km3, 37.1 Ma), Sheep Pasture Formation ( 125 km3, 36 Ma) and, less voluminously, in the Paisano central volcano ( 36.9 Ma) and younger units in the Davis Mountains. Individual lava flows from these units formed fields as extensive as 55 km and 300-m-thick. Flood rhyolite lavas of the Davis Mountains are marginally peralkaline quartz trachyte to low-silica rhyolite. Phenocrysts include alkali feldspar, clinopyroxene, FeTi oxides, and apatite, and, rarely, fayalite, as well as zircon in less peralkaline units. Many Star Mountain flows may be assigned to one of four geochemical groupings. Temperatures were moderately high, ranging from 911 to 860 °C in quartz trachyte and low silica rhyolite. We suggest that flood rhyolite magma evolved from trachyte magma by filter pressing processes, and trachyte from mafic magma in deeper seated plutons. The Davis Mountains segment of Trans-Pecos Texas overlies Grenville basement and is separated from the older Southern Granite and Rhyolite Province to the north by the Grenville Front, and from the younger Coahuila terrane to the south by the Ouachita Front. We suggest that basement structure strongly influenced the timing and nature of Trans-Pecos magmatism, probably in varying degrees of impeding the ascent of mantle-derived mafic magmas, which were produced by upwelling of asthenospheric mantle above the foundered Farallon slab

  7. Oligocene ash flow volcanism, northern Sierra Madre Occidental: Role of mafic and intermediate-composition magmas in rhyolite genesis

    NASA Astrophysics Data System (ADS)

    Wark, David A.

    1991-07-01

    Field, geochemical, and isotopic data from the Tomochic volcanic center in Chihuahua, Mexico, are interpreted to indicate a genetic relationship between large-volume rhyolite ash-flow tuffs and associated more mafic lithologies. These lithologies include (1) porphyritic, two-pyroxene andesite (>35 Ma) that was extruded mostly before ash-flow volcanism, and (2) crystal-poor basaltic andesite that was erupted mostly after ash-flow activity (˜30 Ma) but which was also extruded earlier (˜34 Ma) with hybrid intracaldera lavas. Major silicic units at Tomochic include the Vista (˜34 Ma) and Rio Verde (˜32 Ma) rhyolite ash-flow tuffs; also present are ash-flow tuffs (˜38, 36, and 29 Ma) erupted from other sources. A model of rhyolite genesis by closed-system crystal fractionation of andesite is consistent with geochemical and isotopic data. The least evolved Vista rhyolite was formed by fractionation of ˜65% the original mass of andesite; an additional ˜55% fractionation of plagioclase, alkali feldspar, quartz, biotite, hornblende, FeTi oxides, and sphene generated the most evolved Vista sample. Rio Verde rhyolites were generated from andesite by ˜50% mass fractionation of an assemblage dominated by plagioclase, pyroxene, and FeTi oxides. Initial Nd and Sr isotope ratios of andesite-dacite lavas (ɛNd = -2.3 to -5.2; 87Sr/86Sr = 0.7060 to 0.7089) and of rhyolites (ɛNd = +0.5 to -2.7; 87Sr/86Sr = 0.7053 to 0.7066) partly overlap and extend from values near the mantle array toward values typical of old continental crust on an ɛNd-87Sr/86Sr diagram. These isotope ratios, which do not correlate with indices of differentiation, are interpreted to indicate that parental andesite already contained a crustal component (possibly >20%) before fractionation to rhyolite. The isotopic and geochemical signatures of andesites apparently reflect the incorporation of crust by subduction-related, mafic melts represented by (but more primitive than) exposed basaltic andesites

  8. Mineralogy and geothermometry of high-temperature rhyolites from the central and western Snake River Plain

    USGS Publications Warehouse

    Honjo, N.; Bonnichsen, B.; Leeman, W.P.; Stormer, J.C.

    1992-01-01

    Voluminous mid-Miocene rhyolitic ash-flow tuffs and lava flows are exposed along the northern and southern margins of the central and western Snake River Plain. These rhyolites are essentially anhydrous with the general mineral assemblage of plagioclase ??sanidine ?? quartz + augite + pigeonite ?? hypersthene ?? fayalitic olivine + Fe-Ti oxides + apatite + zircon which provides an opportunity to compare feldspar, pyroxene, and Fe-Ti oxide equilibration temperatures for the same rocks. Estimated pyroxene equilibration temperatures (based on the geothermometers of Lindsley and coworkers) range from 850 to 1000??C, and these are well correlated with whole-rock compositions. With the exception of one sample, agreement between the two-pyroxene thermometers tested is well within 50??C. Fe-Ti oxide geothermometers applied to fresh magnetite and ilmenite generally yield temperatures about 50 to 100??C lower than the pyroxene temperatures, and erratic results are obtained if these minerals exhibit effects of subsolidus oxidation and exsolution. Results of feldspar thermometry are more complicated, and reflect uncertainties in the thermometer calibrations as well as in the degree of attainment of equilibrium between plagioclase and sanidine. In general, temperatures obtained using the Ghiorso (1984) and Green and Usdansky (1986) feldspar thermometers agree with the pyroxene temperatures within the respective uncertainties. However, uncertainties in the feldspar temperatures are the larger of the two (and exceed ??60??C for many samples). The feldspar thermometer of Fuhrman and Lindsley (1988) produces systematically lower temperatures for many of the samples studied. The estimated pyroxene temperatures are considered most representative of actual magmatic temperatures for these rhyolites. This range of temperatures is significantly higher than those for rhyolites from many other suites, and is consistent with the hypothesis that the Snake River Plain rhyolitic magmas formed

  9. Rhyolitic components of the Michipicoten greenstone belt, Ontario: Evidence for late Archaen intracontinental rifts or convergent plate margins in the Canadian Shield?

    NASA Technical Reports Server (NTRS)

    Sylvester, P. J.; Attoh, K.; Schulz, K. J.

    1986-01-01

    Rhyolitic rocks often are the dominant felsic end member of the biomodal volcanic suites that characterize many late Archean greenstone belts of the Canadian Shield. The rhyolites primarily are pyroclastic flows (ash flow tuffs) emplaced following plinian eruptions, although deposits formed by laval flows and phreatomagmatic eruptions also are presented. Based both on measured tectono-stratigraphic sections and provenance studies of greenstone belt sedimentary sequences, the rhyolites are believed to have been equal in abundance to associated basaltic rocks. In many recent discussions of the tectonic setting of late Archean Canadian greenstone belts, rhyolites have been interpreted as products of intracontinental rifting . A study of the tectono-stratigraphic relationships, rock associations and chemical characteristics of the particularly ell-exposed late Archean rhyolites of the Michipicoten greenstone belt, suggests that convergent plate margin models are more appropriate.

  10. Traveltime characteristics of Gore Creek and Black Gore Creek, upper Colorado River basin, Colorado

    USGS Publications Warehouse

    Gurdak, Jason J.; Spahr, Norman E.; Szmajter, Richard J.

    2002-01-01

    In the Rocky Mountains of Colorado, major highways are often constructed in stream valleys. In the event of a vehicular accident involving hazardous materials, the close proximity of highways to the streams increases the risk of contamination entering the streams. Recent population growth has contributed to increased traffic volume along Colorado highways and has resulted in increased movement of hazardous materials, particularly along Interstate 70. Gore Creek and its major tributary, Black Gore Creek, are vulnerable to such contamination from vehicular accidents along Interstate 70. Gore Creek, major tributary of the Eagle River, drains approximately 102 square miles, some of which has recently undergone significant urban development. The headwaters of Gore Creek originate in the Gore Range in the eastern part of the Gore Creek watershed. Gore Creek flows west to the Eagle River. Beginning at the watershed boundary on Vail Pass, southeast of Vail Ski Resort, Interstate 70 parallels Black Gore Creek and then closely follows Gore Creek the entire length of the watershed. Interstate 70 crosses Gore Creek and tributaries 20 times in the watershed. In the event of a vehicular accident involving a contaminant spill into Gore Creek or Black Gore Creek, a stepwise procedure has been developed for water-resource managers to estimate traveltimes of the leading edge and peak concentration of a conservative contaminant. An example calculating estimated traveltimes for a hypothetical contaminant release in Black Gore Creek is provided. Traveltime measurements were made during May and September along Black Gore Creek and Gore Creek from just downstream from the Black Lakes to the confluence with the Eagle River to account for seasonal variability in stream discharge. Fluorometric dye injection of rhodamine WT and downstream dye detection by fluorometry were used to measure traveltime characteristics of Gore Creek and Black Gore Creek. During the May traveltime measurements

  11. Magma Interactions in Rhyolite Reservoirs Caused by Injection of New Rhyolitic Liquid: Results From Analogue Modeling

    NASA Astrophysics Data System (ADS)

    Girard, G.; Stix, J.

    2006-12-01

    Recharge of magma chambers by new inputs of magma is often identified as a trigger for eruptions. However, most studies to date have been carried out on mafic to intermediate composition melts replenishing mafic to silicic reservoirs, often with large compositional differences. Here we focus on rhyolites at large silicic centers such as Yellowstone where no differentiated material other than rhyolite is erupted. We investigate the behavior of rhyolite magma intruding reservoirs of similar composition and temperature, by using analogue experiments with water/corn syrup solutions as analogue magma. The density and viscosity of these solutions range from 1130 to 1320 kg m-3 and 0.008 to 8 Pa s, respectively. The fate of the injected liquid is mainly controlled by the density difference between the injected and resident liquids. Intruding material denser than resident liquid is not able to rise into the reservoir, instead building a flat basal layer or a cone above the discharge point. No further interaction such as mixing occurs. Buoyant injected material rises vertically to the top of the reservoir, also with little interaction involving resident liquid during its ascent. The injected fluid eventually spreads at the top of the reservoir, followed by mixing with the resident phase through the entire reservoir. Variables such as injection rate and viscosity mostly influence the timing and duration of this sequence of events, without changing the final result. The presence of a basal crystal mush, modeled by adding Elvacite plastic grains of 0.15 mm diameter with a density of 1160 kg m-3, does not influence the behavior of a slightly buoyant injection; the injected fluid creates its own path through the mush, eventually rising to the top of the liquid upper part of the reservoir. At the beginning of the injection, however, the intruding liquid must establish a path through the mush. At this stage, the intruding fluid violently entrains substantial numbers of particles

  12. The evolution of Yellowstone's magmatic system over the past 630 kyr: Insights from the crystal record

    NASA Astrophysics Data System (ADS)

    Stelten, M. E.

    2017-12-01

    The Yellowstone Plateau volcanic field in northwestern Wyoming is one of the world's largest, active silicic volcanic centers, and has produced three caldera-forming "super eruptions" over the past 2.1 Myr. As a result, the petrologic evolution of Yellowstone's magmatic system has been the focus of numerous studies over the past 60 years. Early studies at Yellowstone focused on characterizing whole-rock chemical and isotopic variations observed in magmas erupted over Yellowstone's lifetime. While these have provided important insights into the source of Yellowstone magmas and the processes controlling their compositional evolution though time, whole-rock studies are limited in their ability to identify the mechanisms and timescales of rhyolite generation. In contrast, much of the recent work at Yellowstone has focused on applying micro-analytical techniques to characterize the age and composition of phenocrysts hosted in Yellowstone rhyolites. These studies have greatly advanced our understanding of the magmatic system at Yellowstone and have provided crucial new insights into the mechanisms and timescales of rhyolite generation. In particular, recent work has focused on applying micro-analytical techniques to study the age and origin of the [1] three caldera-forming eruptions that produced the Huckleberry Ridge, Mesa Falls, Lava Creek tuffs and [2] post-Lava Creek tuff intracaldera rhyolites that compose the Plateau Rhyolite. As a result, a wealth of crystal-chemical data now exists for rhyolites erupted throughout Yellowstone's 2.1 Myr history. These data provide a unique opportunity to create a detailed reconstruction of Yellowstone's magmatic system through time. In this contribution, I integrate available age, chemical, and isotopic data for phenocrysts hosted in Yellowstone rhyolites to construct a model for the evolution of Yellowstone's magmatic system from the caldera-forming eruption of the Lava Creek tuff at ca. 0.63 Ma to the present day. In particular

  13. Th-230 - U-238 series disequilibrium of the Olkaria rhyolites Gregory Rift Valley, Kenya: Residence times

    NASA Technical Reports Server (NTRS)

    Black, S.; Macdonald, R.; Kelly, M.

    1993-01-01

    U-series disequilibrium analyses have been conducted on samples from Olkaria rhyolite centers with ages being available for all but one center using both internal and whole rock isochrons. 67 percent of the rhyolites analyzed show U-Th disequilibrium, ranging from 27 percent excess thorium to 36 percent excess uranium. Internal and whole rock isochrons give crystallization/formation ages between 65 ka and 9 ka, in every case these are substantially older than the eruptive dates. The residence times of the rhyolites (U-Th age minus the eruption date) have decreased almost linearly with time, from 45 ka to 7 Ka suggesting a possible increase of activity within the system related to increased basaltic input. The long residence times are mirrored by large Rn-222 fluxes from the centers which cannot be explained by larger U contents.

  14. 33 CFR 117.987 - Taylor Bayou.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Taylor Bayou. 117.987 Section 117.987 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Texas § 117.987 Taylor Bayou. The draws of the Union Pacific...

  15. 33 CFR 117.987 - Taylor Bayou.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Taylor Bayou. 117.987 Section 117.987 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Texas § 117.987 Taylor Bayou. The draws of the Union Pacific...

  16. Flood discharges and hydraulics near the mouths of Wolf Creek, Craig Branch, Manns Creek, Dunloup Creek, and Mill Creek in the New River Gorge National River, West Virginia

    USGS Publications Warehouse

    Wiley, J.B.

    1994-01-01

    The U.S. Geological Survey, in cooperation with the National Park Service, studied the frequency and magnitude of flooding near the mouths of five tributaries to the New River in the New River Gorge National River. The 100-year peak discharge at each tributary was determined from regional frequency equations. The 100-year discharge at Wolf Creek, Craig Branch, Manns Creek, Dunloup Creek, and Mill Creek was 3,400 cubic feet per second, 640 cubic feet per second, 8,200 cubic feet per second, 7,100 cubic feet per second, and 9,400 cubic feet per second, respectively. Flood elevations for each tributary were determined by application of a steady-state, one-dimensional flow model. Manning's roughness coefficients for the stream channels ranged from 0.040 to 0.100. Bridges that would be unable to contain the 100-year flood within the bridge opening included: the State Highway 82 bridge on Wolf Creek, the second Fayette County Highway 25 bridge upstream from the confluence with New River on Dunloup Creek, and an abandoned log bridge on Mill Creek.

  17. Age of the Lava Creek supereruption and magma chamber assembly at Yellowstone based on 40Ar/39Ar and U-Pb dating of sanidine and zircon crystals

    USGS Publications Warehouse

    Matthews, Naomi E.; Vazquez, Jorge A.; Calvert, Andrew T.

    2015-01-01

    The last supereruption from the Yellowstone Plateau formed Yellowstone caldera and ejected the >1000 km3 of rhyolite that composes the Lava Creek Tuff. Tephra from the Lava Creek eruption is a key Quaternary chronostratigraphic marker, in particular for dating the deposition of mid Pleistocene glacial and pluvial deposits in western North America. To resolve the timing of eruption and crystallization history for the Lava Creek magma, we performed (1) 40Ar/39Ar dating of single sanidine crystals to delimit eruption age and (2) ion microprobe U-Pb and trace-element analyses of the crystal faces and interiors of single zircons to date the interval of zircon crystallization and characterize magmatic evolution. Sanidines from the two informal members composing Lava Creek Tuff yield a preferred 40Ar/39Ar isochron date of 631.3 ± 4.3 ka. Crystal faces on zircons from both members yield a weighted mean 206Pb/238U date of 626.5 ± 5.8 ka, and have trace element concentrations that vary with the eruptive stratigraphy. Zircon interiors yield a mean 206Pb/238U date of 659.8 ± 5.5 ka, and reveal reverse and/or oscillatory zoning of trace element concentrations, with many crystals containing high U concentration cores that likely grew from highly evolved melt. The occurrence of distal Lava Creek tephra in stratigraphic sequences marking the Marine Isotope Stage 16–15 transition supports the apparent eruption age of ∼631 ka. The combined results reveal that Lava Creek zircons record episodic heating, renewed crystallization, and an overall up-temperature evolution for Yellowstone's subvolcanic reservoir in the 103−104 year interval before eruption.

  18. Two types of gabbroic xenoliths from rhyolite dominated Niijima volcano, northern part of Izu-Bonin arc: petrological and geochemical constraints

    NASA Astrophysics Data System (ADS)

    Arakawa, Yoji; Endo, Daisuke; Ikehata, Kei; Oshika, Junya; Shinmura, Taro; Mori, Yasushi

    2017-03-01

    We examined the petrography, petrology, and geochemistry of two types of gabbroic xenoliths (A- and B-type xenoliths) in olivine basalt and biotite rhyolite units among the dominantly rhyolitic rocks in Niijima volcano, northern Izu-Bonin volcanic arc, central Japan. A-type gabbroic xenoliths consisting of plagioclase, clinopyroxene, and orthopyroxene with an adcumulate texture were found in both olivine basalt and biotite rhyolite units, and B-type gabbroic xenoliths consisting of plagioclase and amphibole with an orthocumulate texture were found only in biotite rhyolite units. Geothermal- and barometricmodelling based on mineral chemistry indicated that the A-type gabbro formed at higher temperatures (899-955°C) and pressures (3.6-5.9 kbar) than the B-type gabbro (687-824°C and 0.8-3.6 kbar). These findings and whole-rock chemistry suggest different parental magmas for the two types of gabbro. The A-type gabbro was likely formed from basaltic magma, whereas the B-type gabbro was likely formed from an intermediate (andesitic) magma. The gabbroic xenoliths in erupted products at Niijima volcano indicate the presence of mafic to intermediate cumulate bodies of different origins at relatively shallower levels beneath the dominantly rhyolitic volcano.

  19. Isotopic and chemical evidence concerning the genesis and contamination of basaltic and rhyolitic magma beneath the Yellowstone Plateau Volcanic Field

    USGS Publications Warehouse

    Hildreth, W.; Halliday, A.N.; Christiansen, R.L.

    1991-01-01

    Since 2.2 Ma, the Yellowstone Plateau Volcanic Field has produced ~6000 km3 of rhyolite tuffs and lavas in >60 separate eruptions, as well as ~100 km3 of tholeiitic basalt from >50 vents peripheral to the silicic focus. Intermediate eruptive products are absent. Early postcollapse rhyolites show large shifts in Nd, Sr, Pb, and O isotopic composition caused by assimilation of roof rocks and hydrothermal brines during collapse and resurgence. Younger intracaldera rhyolite lavas record partial isotopic recovery toward precaldera ratios. Thirteen extracaldera rhyolites show none of these effects and have sources independent of the subcaldera magma system. Contributions from the Archaean crust have extreme values and wide ranges of Nd-, Sr, and Pb-isotope ratios, but Yellowstone rhyolites have moderate values and limited ranges. This requires their deep-crustal sources to have been pervasively hybridized by distributed intrusion of Cenozoic basalt, most of which was probably contemporaneous with the Pliocene and Quaternary volcanism. Most Yellowstone basalts had undergone cryptic clinopyroxene fractionation in the lower crust or crust-mantle transition zone and, having also ascended through or adjacent to crustal zones of silicic-magma generation, most underwent some crustal contamination. -from Authors

  20. 238U-230Th dating of chevkinite in high-silica rhyolites from La Primavera and Yellowstone calderas

    USGS Publications Warehouse

    Vazquez, Jorge A.; Velasco, Noel O.; Schmitt, Axel K.; Bleick, Heather A.; Stelten, Mark E.

    2014-01-01

    Application of 238U-230Th disequilibrium dating of accessory minerals with contrasting stabilities and compositions can provide a unique perspective on magmatic evolution by placing the thermochemical evolution of magma within the framework of absolute time. Chevkinite, a Th-rich accessory mineral that occurs in peralkaline and metaluminous rhyolites, may be particularly useful as a chronometer of crystallization and differentiation because its composition may reflect the chemical changes of its host melt. Ion microprobe 128U-230Th dating of single chevkinite microphenocrysts from pre- and post-caldera La Primavera, Mexico, rhyolites yields model crystallization ages that are within 10's of k.y. of their corresponding K-Ar ages of ca. 125 ka to 85 ka, while chevkinite microphenocrysts from a post-caldera Yellowstone, USA, rhyolite yield a range of ages from ca. 110 ka to 250 ka, which is indistinguishable from the age distribution of coexisting zircon. Internal chevkinite-zircon isochrons from La Primavera yield Pleistocene ages with ~5% precision due to the nearly two order difference in Th/U between both minerals. Coupling chevkinite 238U-230Th ages and compositional analyses reveals a secular trend of Th/U and rare earth elements recorded in Yellowstone rhyolite, likely reflecting progressive compositional evolution of host magma. The relatively short timescale between chevkinite-zircon crystallization and eruption suggests that crystal-poor rhyolites at La Primavera were erupted shortly after differentiation and/or reheating. These results indicate that 238U-230Th dating of chevkinite via ion microprobe analysis may be used to date crystallization and chemical evolution of silicic magmas.

  1. Do Processes of Rhyolite Genesis Change as Icelandic Rifts Drift off of the Plume?

    NASA Astrophysics Data System (ADS)

    Jordan, B. T.

    2004-12-01

    The abandoned Snaefellsnes rift zone in western Iceland was the on-land manifestation of the Mid-Atlantic Ridge between 15 and 7 Ma. The rift zone was abandoned at 7 Ma, after it had drifted westward off of the Iceland hotspot, generally interpreted as a mantle plume. The position of the abandoned rift was initially recognized as the axis of a regional syncline analogous to the syncline developed in response to active rifting. Previous paleomagnetic and geochronologic studies have confirmed the position of the abandoned rift axis. Recent seismic tomography shows that the abandoned rift is also characterized by relatively thin crust (<20 km, versus up to 46 km above the plume). In the context of supervising Keck Geology Consortium undergraduate research projects in northwestern Iceland in 2003 and 2004, I have studied several silicic centers erupted at different times along the northern Snaefellsnes rift. A compilation of preliminary geochemical data from the Skagi area near the rift reveals several interesting trends that bear on the origin of silicic magmas as activity in the rift was waning. The compositional spectrum of silicic rocks in this area is from dacite (67 wt.% SiO2) to rhyolite (75 wt.% SiO2). Positive correlation between Na2O and SiO2 is consistent with either fractionation or decreasing degrees of crustal melting to get from dacite to rhyolite. However, Zr correlates negatively with SiO2, consistent with zircon fractionation, but inconsistent with variation in the degree of melting unless zircon is present in the source, unlikely for the meta-basaltic crust of Iceland. Therefore, I suggest these rocks reflect extreme (>90%) fractionation of a basaltic parent. A similar argument was advanced by Furman et al. (1992, J. Pet., 1405-1445) for rhyolites at Austerhorn in eastern Iceland. Compelling arguments have been previously advanced that most rhyolites erupted in the modern rifts of Iceland are the products of crustal melting. The same has been argued

  2. The volcanic history of Volcán Alcedo, Galápagos Archipelago: a case study of rhyolitic oceanic volcanism

    USGS Publications Warehouse

    Geist, Dennis J.; Howard, Keith A.; Jellinek, A. Mark; Rayder, Scott

    1994-01-01

    Volcán Alcedo is one of the seven western Galápagos shields and is the only active Galápagos volcano known to have erupted rhyolite as well as basalt. The volcano stands 4 km above the sea floor and has a subaerial volume of 200 km3, nearly all of which is basalt. As Volcán Alcedo grew, it built an elongate domal shield, which was partly truncated during repeated caldera-collapse and partial-filling episodes. An outward-dipping sequence of basalt flows at least 250 m thick forms the steepest (to 33°) flanks of the volcano and is not tilted; thus a constructional origin for the steep upper flanks is favored. About 1 km3 of rhyolite erupted late in the volcano's history from at least three vents and in 2–5 episodes. The most explosive of these produced a tephra blanket that covers the eastern half of the volcano. Homogeneous rhyolitic pumice is overlain by dacite-rhyolite commingled pumice, with no stratigraphic break. The tephra is notable for its low density and coarse grain size. The calculated height of the eruption plume is 23–30 km, and the intensity is estimated to have been 1.2x108 kg/s. Rhyolitic lavas vented from the floor of the caldera and from fissures along the rim overlie the tephra of the plinian phase. The age of the rhyolitic eruptions is ≤120 ka, on the basis of K-Ar ages. Between ten and 20 basaltic lava flows are younger than the rhyolites. Recent faulting resulted in a moat around part of the caldera floor. Alcedo most resently erupted sometime between 1946 and 1960 from its southern flank. Alcedo maintains an active, transient hydrothermal system. Acoustic and seismic activity in 1991 is attributed to the disruption of the hydrothermal system by a regional-scale earthquake.

  3. Growth of Megaspherulites In a Rhyolitic Vitrophyre

    NASA Technical Reports Server (NTRS)

    Smith, Robert K.; Tremallo, Robin L.; Lofgren, Gary E.

    2000-01-01

    Megaspherulites occur in the middle zone of a thick sequence of rhyolitic vitrophyre that occupies a small, late Eocene to early Oligocene volcanic-tectonic basin near Silver Cliff, Custer County, Colorado. Diameters of the megaspherulites range from 0.3 m to over 3.66 m, including a clay envelope. The megaspherulites are compound spherulites. consisting of an extremely large number (3.8 x 10(exp 9) to 9.9 x 10(exp 9)) of individual growth cones averaging 3 mm long by 1.25 mm wide at their termination. They are holocrystalline, very fine- to fine-grained, composed of disordered to ordered sanidine (orthoclase) and quartz, and surrounded by a thin K-feldspar, quartz rich rind, an inner clay layer with mordenite, and an outer clay layer composed wholly of 15 A montmorillonite. Whole rock analyses of the megaspherulites show a restricted composition from their core to their outer edge, with an average analyses of 76.3% SiO2, 0.34% CaO, 2.17% Na2O, 6.92% K2O, 0.83% H2O+ compared to the rhyolitic vitrophyre from which they crystallize with 71.07% SiO2, 0.57% CaO, 4.06% Na2O,4.l0% K2O, and 6.40% H2O+. The remaining oxides of Fe2O3 (total Fe), A12O3, MnO,MgO, TiO2, P2O5, Cr2O3, and trace elements show uniform distribution between the megaspherulites and the rhyolitic vitrophyre. Megaspherulite crystallization began soon after the rhyolitic lava ceased to flow as the result of sparse heterogeneous nucleation, under nonequilibrium conditions, due to a high degree of undercooling, delta T. The crystals grow with a fibrous habit which is favored by a large delta T ranging between 245 C and 295 C, despite lowered viscosity, and enhanced diffusion due to the high H2O content, ranging between 5% and 7%. Therefore, megaspherulite growth proceeded in a diffusion controlled manner, where the diffusion, rate lags behind the crystal growth rate at the crystal-liquid interface, restricting fibril lengths and diameters to the 10 micron to 15 micron and 3 micron and 8 micron ranges

  4. Restoring Fossil Creek

    ERIC Educational Resources Information Center

    Flaccus, Kathleen; Vlieg, Julie; Marks, Jane C.; LeRoy, Carri J.

    2004-01-01

    Fossil Creek had been dammed for the past 90 years, and plans were underway to restore the stream. The creek runs through Central Arizona and flows from the high plateaus to the desert, cutting through the same formations that form the Grand Canyon. This article discusses the Fossil Creek monitoring project. In this project, students and teachers…

  5. Water-quality appraisal. Mammoth Creek and Hot Creek, Mono County, California

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Setmire, J.G.

    1984-06-01

    A late summer reconnaissance in 1981 and a spring high-flow sampling in 1982 of Mammoth Creek and Hot Creek, located in the Mammoth crest area of the Sierra Nevada, indicated that three water-quality processes were occurring: (1) mineralization; (2) eutrophication; and (3) sedimentation. Limited areas of fecal contamination were also observed. Mineralization due primarily to geothermal springs increased dissolved-solids concentration downstream, which changed the chemical composition of the water. The percentage of calcium decreased gradually, the percentage of magnesium and sodium increased, and the percentage of fluoride, sulfate, and chloride fluctuated, but increased overall. These changes produced water quality inmore » Mammoth Creek similar to that of the springs forming Hot Creek. Twin Lakes and the reach of Hot Creek below the fish hatchery showed evidence of eutrophication. Twin Lakes had floating mats of algae and a high dissolved-oxygen saturation of 147% at a pH of 9.2. Hot Creek had abundant growth of aquatic vascular plants and algae, dissolved-oxygen saturations ranging from 65% to 200%, algal growth potential of 30 milligrams per liter, nitrate concentration of 0.44 milligram per liter, and phosphate concentration of 0.157 milligram per liter. Sediment deposition was determined from detailed observations of bed-material composition, which showed that fine material was deposited at Sherwin Creek Road and downstream. Fecal contamination was indicated by fecal-coliform bacteria counts of 250 colonies per 100 milliliters and fecal-streptococcal bacteria counts greater than 1000 colonies per 100 milliliters. Although bacterial sampling was sporadic and incomplete, it did indicate adverse effects on water quality for the following beneficial uses that have been identified for Mammoth Creek and Hot Creek: (1) municipal supply; (2) cold-water habitat; and (3) contact and noncontact water recreation. 6 refs., 15 figs., 15 tabs.« less

  6. String-theoretic deformation of the Parke-Taylor factor

    NASA Astrophysics Data System (ADS)

    Mizera, Sebastian; Zhang, Guojun

    2017-09-01

    Scattering amplitudes in a range of quantum field theories can be computed using the Cachazo-He-Yuan (CHY) formalism. In theories with color ordering, the key ingredient is the so-called Parke-Taylor factor. In this paper we give a fully SL (2 ,C )-covariant definition and study the properties of a new integrand called the "string Parke-Taylor" factor. It has an α' expansion whose leading coefficient is the field-theoretic Parke-Taylor factor. Its main application is that it leads to a CHY formulation of open string tree-level amplitudes. In fact, the definition of the string Parke-Taylor factor was motivated by trying to extend the compact formula for the first α' correction found by He and Zhang, while the main ingredient in its definition is a determinant of a matrix introduced in the context of string theory by Stieberger and Taylor.

  7. The Complex History of Alarcon Rise Mid-Ocean Ridge Rhyolite Revealed through Mineral Chemistry

    NASA Astrophysics Data System (ADS)

    Dreyer, B. M.; Portner, R. A.; Clague, D. A.; Daczko, N. R.; Castillo, P.; Bindeman, I. N.

    2014-12-01

    A suite of basalts to rhyolites recovered from the Alarcon Rise, the northern extension of the intermediate spreading-rate East Pacific Rise, provides an unparalleled test of established mechanisms for high-Si lava formation at ridges. Rhyolites are ≤35% phyric and poorly vesicular. Mafic xenoclasts are common, and plagioclase is the dominant phase. Olivine and clinopyroxene are also common, and orthopyroxene, FeTi-oxides, zircon, and rare pyrite blebs are present. Major and trace element glass data are consistent with MELTS models of fractional crystallization from a parental melt, but a diverse mineral population records added complexity. Olivine and plagioclase compositions are broadly consistent with models, with the exception of more variable Fo52-77 and An87-28 in a basaltic andesitic composition where pigeonite is predicted to replace olivine in the crystallizing assemblage between ~1085-1015°C; pigeonites analyzed in an andesite have lower Ca and Fe than predicted. Clinopyroxene variability generally increases with host melt SiO2, from Mg# 86-84 in basalts to Mg# 80-21 in rhyolites, and zoning is common with higher-MgO anhedral cores mantled by lower-MgO euhedral rims. Cooler magmas aided the preservation of disequilibrium and are supported by ~715-835°C Ti-in-zircon and ilmenite-magnetite thermometry in rhyolites. Despite a well-predicted liquid line of decent, multiple signals of chemical disequilibrium in intermediate to silicic melts support mixing of magmatic batches and/or assimilation of partially hydrous crust. Assimilation is permissible given δ18O values that are lower than expected solely from fractional crystallization (i.e., <6.3‰ at 77% SiO2), but assimilation extent is limited on the basis of δD ~82±8 and Pacific MORB-like 87Sr/86Sr. Zircon Hf-isotopes and trace element patterns support a juvenile oceanic crustal source. Whereas depleted Pacific MORB mantle source reservoir is supported by whole rock Sr-Nd isotopes, slight

  8. Thermal diffusivity of rhyolitic glasses and melts: effects of temperature, crystals and dissolved water

    NASA Astrophysics Data System (ADS)

    Romine, William L.; Whittington, Alan G.; Nabelek, Peter I.; Hofmeister, Anne M.

    2012-12-01

    Thermal diffusivity ( D) was measured using laser-flash analysis on pristine and remelted obsidian samples from Mono Craters, California. These high-silica rhyolites contain between 0.013 and 1.10 wt% H2O and 0 to 2 vol% crystallites. At room temperature, D glass varies from 0.63 to 0.68 mm2 s-1, with more crystalline samples having higher D. As T increases, D glass decreases, approaching a constant value of ˜0.55 mm2 s-1 near 700 K. The glass data are fit with a simple model as an exponential function of temperature and a linear function of crystallinity. Dissolved water contents up to 1.1 wt% have no statistically significant effect on the thermal diffusivity of the glass. Upon crossing the glass transition, D decreases rapidly near ˜1,000 K for the hydrous melts and ˜1,200 K for anhydrous melts. Rhyolitic melts have a D melt of ˜0.51 mm2 s-1. Thermal conductivity ( k = D· ρ· C P) of rhyolitic glass and melt increases slightly with T because heat capacity ( C P) increases with T more strongly than density ( ρ) and D decrease. The thermal conductivity of rhyolitic melts is ˜1.5 W m-1 K-1, and should vary little over the likely range of magmatic temperatures and water contents. These values of D and k are similar to those of major crustal rock types and granitic protoliths at magmatic temperatures, suggesting that changes in thermal properties accompanying partial melting of the crust should be relatively minor. Numerical models of shallow rhyolite intrusions indicate that the key difference in thermal history between bodies that quench to obsidian, and those that crystallize, results from the release of latent heat of crystallization. Latent heat release enables bodies that crystallize to remain at high temperatures for much longer times and cool more slowly than glassy bodies. The time to solidification is similar in both cases, however, because solidification requires cooling through the glass transition in the first case, and cooling only to the

  9. Water-quality appraisal, Mammoth Creek and Hot Creek, Mono County, California

    USGS Publications Warehouse

    Setmire, J.G.

    1984-01-01

    A late summer reconnaissance in 1981 and a spring high-flow sampling in 1982 of Mammoth Creek and Hot Creek, located in the Mammoth crest area of the Sierra Nevada, indicated that mineralization, eutrophication, sedimentation, and limited areas of fecal contamination were occurring. Mineralization, indicated by a downstream increase in dissolved-solids concentration, was due primarily to geothermal springs that gradually decreased in the percentage of calcium, increased in the percentage of magnesium and sodium, and caused fluctuating, but overall increasing percentage of fluoride, sulfate, and chloride. Resulting water quality in Mammoth Creek was similar to that of the springs forming Hot Creek. Eutrophication was observed in Twin Lakes and the reach of Hot Creek below the fish hatchery. Twin Lakes had floating mats of algae and a high dissolved-oxygen saturation of 147 percent at a pH of 9.2. Hot Creek had excessive aquatic vascular plant and algae growth, dissolved-oxygen saturations ranging from 65 to 200 percent, algal growth potential of 30 milligrams per liter, and nitrates and phosphates of 0.44 and 0.157 milligrams per liter. Sedimentation was noted in observations of bed-material composition showing the presence of fine material beginning at Sherwin Creek Road. Fecal contamination was indicated by fecal coliform counts of 250 colonies per 100 milliliters and fecal streptococcal counts greater than 1,000 colonies per 100 milliliters. (USGS)

  10. Lower Walnut Creek Restoration

    EPA Pesticide Factsheets

    Lower Walnut Creek Restoration Project will restore and enhance coastal wetlands along southern shoreline of Suisun Bay from Suisun Bay upstream along Walnut Creek, improving habitat quality, diversity, and connectivity along three miles of creek channel.

  11. Taylorism and the Logic of Learning Outcomes

    ERIC Educational Resources Information Center

    Stoller, Aaron

    2015-01-01

    This essay examines the shared philosophical foundations of Fredrick W. Taylor's scientific management principles and the contemporary learning outcomes movement (LOM). It analyses the shared philosophical ground between the focal point of Taylor's system--"the task"--and the conceptualization and deployment of "learning…

  12. Emplacement model of obsidian-rhyolite magma deduced from complete internal section of the Akaishiyama lava, Shirataki, northern Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Wada, K.; Sano, K.

    2016-12-01

    Simultaneously explosive and effusive eruptions of silicic magmas has shed light on the vesiculation and outgassing history of ascending magmas in the conduit and emplacement model of obsidian-rhyolite lavas (Castro et al., 2014; Shipper et al, 2013). As well as the knowledge of newly erupted products such as 2008-2009 Chaitén and 2011-2012 Cordón Caule eruptions, field and micro-textural evidences of well-exposed internal structure of obsidian-rhyolite lava leads to reveal eruption processes of silicic magmas. The Shirataki monogenetic volcano field, 2.2 million year age, northern Hokkaido, Japan, contains many outcrops of obsidian and vesiculated rhyolite zones (SiO2=76.7-77.4 wt.%). Among their outcrops, Akaishiyama lava shows good exposures of internal sections from the top to the bottom along the Kyukasawa valley with thickness of about 190 meters, showing the symmetrical structure comprising a upper clastic zone (UCZ; 5m thick), an upper dense obsidian zone (UDO; 15m), an upper banded obsidian zone (UBO; 70-80m), a central rhyolite zone (CR; 65m), a lower banded obsidian zone (LBO; 15m), a lower dense obsidian zone (LDO; 20m), and a lower clastic zone (LCZ; 3m). The upper banded obsidian zone is characterized by existence of spherulite concentration layers with tuffisite veins and rhyolite enclaves. Spherulites consisting of albite, cristobalaite and obsidian glass, are clustered in the dense obsidian. Tuffisite veins show brecciated obsidians in tuffaceous matrix, showing an outgassing path during the emplacement of obsidian lava. Perpendicular dip of spherulite parallel rows indicates the banded zone itself was the domain of vent area. From the observation of these occurrences in the internal section and rock texture, we show the qualitative formation model of Shirataki obsidian-rhyolite lava.

  13. The Life and Legacy of G. I. Taylor

    NASA Astrophysics Data System (ADS)

    Batchelor, G. K.

    1996-07-01

    G.I. Taylor, one of the most distinguished physical scientists of this century, used his deep insight and originality to increase our understanding of phenomena such as the turbulent flow of fluids. His interest in the science of fluid flow was not confined to theory; he was one of the early pioneers of aeronautics, and designed a new type of anchor that was inspired by his passion for sailing. Taylor spent most of his working life in the Cavendish Laboratory in Cambridge, where he investigated the mechanics of fluid and solid materials; his discoveries and ideas have had application throughout mechanical, civil, and chemical engineering, meteorology, oceanography and materials science. He was also a noted research leader, and his group in Cambridge became one of the most productive centers for the study of fluid mechanics. How was Taylor able to be innovative in so many different ways? This interesting and unusual biography helps answer that question. Professor Batchelor, himself a student and close collaborator of Taylor, is ideally placed to describe Taylor's life, achievements and background. He does so without introducing any mathematical details, making this book enjoyable reading for a wide range of people--and especially those whose own interests have brought them into contact with the legacy of Taylor.

  14. Isotopically-diverse rhyolites coeval with the Columbia River Basalts Large Igneous Province: evidence for widespread mantle-plume driven hydrothermal alteration and remelting of the crust

    NASA Astrophysics Data System (ADS)

    Colon, D.; Bindeman, I. N.; Stern, R. A.; Fisher, C. M.

    2014-12-01

    The formation of the most recent flood basalt province on Earth, the Columbia River Flood Basalts (CRBs) of the northwestern USA, was accompanied by eruptions of several thousand km3 of rhyolite in a short time window from 16.7 to 15 Ma. These rhyolites span from low (+1‰) to high (+11‰) in δ18O values as recorded by major phenocrysts, and alteration-resistant zircons within each rhyolite commonly display diversity of up to 6‰ δ18O, indicative of batch assembly prior to eruption. Significant variation in ɛHf also exists in zircons, ranging from -39 to 0 in rhyolites erupted through the North American cratonic crust, and from -1 to +9 in rhyolites erupted through accreted oceanic terranes to the east of the Sr87/86Sr = 0.706 line. This isotopic diversity cannot be accounted for by fractionation of a CRB-like parent magma, demonstrating that the syn-CRB rhyolites must have been derived from melting of the crust. Abundant low-δ18Omelt values among syn-CRB rhyolites further constrains this crustal melting to shallow depths of 5-10 km, due to the shallow depths of the necessary hydrothermal alteration of the protolith. By contrast, high-δ18O rhyolites must have been formed by remelting of sedimentary or metasedimentary rocks. Low-δ18O rhyolites are also most common in the vicinity of the crustal suture between the thick lithosphere of the Archean craton and the thin lithosphere of the accreted terranes. Thermomechanical modeling suggests that this contrast concentrates crustal heating and deformation, creating pathways for meteoric water to penetrate the crust and cause extensive hydrothermal alteration less than 1 Ma before those same rocks remelt to form low-δ18O rhyolites. Finally, we suggest that this extensive crustal hydrothermal alteration and melting may be typical of continental flood basalt provinces world wide, and particularly when there is syn-volcanic extension.

  15. Accessory mineral U-Th-Pb ages and 40Ar/39Ar eruption chronology, and their bearing on rhyolitic magma evolution in the Pleistocene Coso volcanic field, California

    USGS Publications Warehouse

    Simon, J.I.; Vazquez, J.A.; Renne, P.R.; Schmitt, A.K.; Bacon, C.R.; Reid, M.R.

    2009-01-01

    We determined Ar/Ar eruption ages of eight extrusions from the Pleistocene Coso volcanic field, a long-lived series of small volume rhyolitic domes in eastern California. Combined with ion-microprobe dating of crystal ages of zircon and allanite from these lavas and from granophyre geothermal well cuttings, we were able to track the range of magma-production rates over the past 650 ka at Coso. In ??? 230 ka rhyolites we find no evidence of protracted magma residence or recycled zircon (or allanite) from Pleistocene predecessors. A significant subset of zircon in the ???85 ka rhyolites yielded ages between ???100 and 200 Ma, requiring that generation of at least some rhyolites involves material from Mesozoic basement. Similar zircon xenocrysts are found in an ???200 ka granophyre. The new age constraints imply that magma evolution at Coso can occur rapidly as demonstrated by significant changes in rhyolite composition over short time intervals (???10's to 100's ka). In conjunction with radioisotopic age constraints from other young silicic volcanic fields, dating of Coso rhyolites highlights the fact that at least some (and often the more voluminous) rhyolites are produced relatively rapidly, but that many small-volume rhyolites likely represent separation from long-lived mushy magma bodies. ?? The Author(s) 2009.

  16. Magmatic processes that generated the rhyolite of Glass Mountain, Medicine Lake volcano, N. California

    USGS Publications Warehouse

    Grove, T.L.; Donnelly-Nolan, J. M.; Housh, T.

    1997-01-01

    Glass Mountain consists of a 1 km3, compositionally zoned rhyolite to dacite glass flow containing magmatic inclusions and xenoliths of underlying shallow crust. Mixing of magmas produced by fractional crystallization of andesite and crustal melting generated the rhyolite of Glass Mountain. Melting experiments were carried out on basaltic andesite and andesite magmatic inclusions at 100, 150 and 200 MPa, H2O-saturated with oxygen fugacity controlled at the nickel-nickel oxide buffer to provide evidence of the role of fractional crystallization in the origin of the rhyolite of Glass Mountain. Isotopic evidence indicates that the crustal component assimilated at Glass Mountain constitutes at least 55 to 60% of the mass of erupted rhyolite. A large volume of mafic andesite (2 to 2.5 km3) periodically replenished the magma reservoir(s) beneath Glass Mountain, underwent extensive fractional crystallization and provided the heat necessary to melt the crust. The crystalline residues of fractionation as well as residual liquids expelled from the cumulate residues are preserved as magmatic inclusions and indicate that this fractionation process occurred at two distinct depths. The presence and composition of amphibole in magmatic inclusions preserve evidence for crystallization of the andesite at pressures of at least 200 MPa (6 km depth) under near H2O-saturated conditions. Mineralogical evidence preserved in olivine-plagioclase and olivine-plagioclase-high-Ca clinopyroxene-bearing magmatic inclusions indicates that crystallization under near H2O-saturated conditions also occurred at pressures of 100 MPa (3 km depth) or less. Petrologic, isotopic and geochemical evidence indicate that the andesite underwent fractional crystallization to form the differentiated melts but had no chemical interaction with the melted crustal component. Heat released by the fractionation process was responsible for heating and melting the crust.

  17. 76 FR 3570 - Proposed Amendment of Class E Airspace; Taylor, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-20

    ...-1189; Airspace Docket No. 10-AWP-19] Proposed Amendment of Class E Airspace; Taylor, AZ AGENCY: Federal... proposes to modify Class E airspace at Taylor Airport, Taylor, AZ. Controlled airspace is necessary to accommodate aircraft using the CAMBO One Departure Area Navigation (RNAV) out of Taylor Airport. The FAA is...

  18. Simulation of streamflow and estimation of recharge to the Edwards aquifer in the Hondo Creek, Verde Creek, and San Geronimo Creek watersheds, south-central Texas, 1951-2003

    USGS Publications Warehouse

    Ockerman, Darwin J.

    2005-01-01

    The U.S. Geological Survey, in cooperation with the San Antonio Water System, constructed three watershed models using the Hydrological Simulation Program—FORTRAN (HSPF) to simulate streamflow and estimate recharge to the Edwards aquifer in the Hondo Creek, Verde Creek, and San Geronimo Creek watersheds in south-central Texas. The three models were calibrated and tested with available data collected during 1992–2003. Simulations of streamflow and recharge were done for 1951–2003. The approach to construct the models was to first calibrate the Hondo Creek model (with an hourly time step) using 1992–99 data and test the model using 2000–2003 data. The Hondo Creek model parameters then were applied to the Verde Creek and San Geronimo Creek watersheds to construct the Verde Creek and San Geronimo Creek models. The simulated streamflows for Hondo Creek are considered acceptable. Annual, monthly, and daily simulated streamflows adequately match measured values, but simulated hourly streamflows do not. The accuracy of streamflow simulations for Verde Creek is uncertain. For San Geronimo Creek, the match of measured and simulated annual and monthly streamflows is acceptable (or nearly so); but for daily and hourly streamflows, the calibration is relatively poor. Simulated average annual total streamflow for 1951–2003 to Hondo Creek, Verde Creek, and San Geronimo Creek is 45,400; 32,400; and 11,100 acre-feet, respectively. Simulated average annual streamflow at the respective watershed outlets is 13,000; 16,200; and 6,920 acre-feet. The difference between total streamflow and streamflow at the watershed outlet is streamflow lost to channel infiltration. Estimated average annual Edwards aquifer recharge for Hondo Creek, Verde Creek, and San Geronimo Creek watersheds for 1951–2003 is 37,900 acrefeet (5.04 inches), 26,000 acre-feet (3.36 inches), and 5,940 acre-feet (1.97 inches), respectively. Most of the recharge (about 77 percent for the three watersheds

  19. The New Taylorism: Hacking at the Philosophy of the University's End

    ERIC Educational Resources Information Center

    Goodman, Robin Truth

    2012-01-01

    This article looks at the critical writings of Mark C. Taylor. It suggests that Mark C. Taylor is rewriting a global imaginary devoid of the kind of citizenship that Henry Giroux claims as the basis for public education. Instead, Taylor wants to see the university take shape as profit-generating. According to Taylor, in lieu of learning to take…

  20. Emplacement of the Rocche Rosse rhyolite lava flow (Lipari, Aeolian Islands)

    NASA Astrophysics Data System (ADS)

    Bullock, Liam A.; Gertisser, Ralf; O'Driscoll, Brian

    2018-05-01

    The Rocche Rosse lava flow marks the most recent rhyolitic extrusion on Lipari island (Italy), and preserves evidence for a multi-stage emplacement history. Due to the viscous nature of the advancing lava (108 to 1010 Pa s), indicators of complex emplacement processes are preserved in the final flow. This study focuses on structural mapping of the flow to highlight the interplay of cooling, crust formation and underlying slope in the development of rhyolitic lavas. The flow is made up of two prominent lobes, small (< 0.2 m) to large (> 0.2 m) scale folding and a channelled geometry. Foliations dip at 2-4° over the flatter topography close to the vent, and up to 30-50° over steeper mid-flow topography. Brittle faults, tension gashes and conjugate fractures are also evident across flow. Heterogeneous deformation is evident through increasing fold asymmetry from the vent due to downflow cooling and stagnation. A steeper underlying topography mid-flow led to development of a channelled morphology, and compression at topographic breaks resulted in fold superimposition in the channel. We propose an emplacement history that involved the evolution through five stages, each associated with the following flow regimes: (1) initial extrusion, crustal development and small scale folding; (2) extensional strain, stretching lineations and channel development over steeper topography; (3) compression at topographic break, autobrecciation, lobe development and medium scale folding; (4) progressive deformation with stagnation, large-scale folding and re-folding; and (5) brittle deformation following flow termination. The complex array of structural elements observed within the Rocche Rosse lava flow facilitates comparisons to be made with actively deforming rhyolitic lava flows at the Chilean volcanoes of Chaitén and Cordón Caulle, offering a fluid dynamic and structural framework within which to evaluate our data.

  1. 20. TURNTABLE WITH CABLE CAR BAY & TAYLOR: View ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. TURNTABLE WITH CABLE CAR - BAY & TAYLOR: View to northwest of the Bay and Taylor turntable. The gripman and conductor are turning the car around. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  2. Bonanza Creek Experimental Forest & Caribou-Poker Creeks Research Watershed.

    Treesearch

    Valerie Rapp

    2003-01-01

    Bonanza Creek Experimental Forest and Caribou-Poker Creeks Research Watershed are located in the boreal forest of interior Alaska. Research focuses on basic ecological processes, hydrology, disturbance regimes, and climate change in the boreal forest region. Interior Alaska lies between the Alaska Range to the south and the Brooks Range to the north and covers an area...

  3. Taylor dispersion of colloidal particles in narrow channels

    NASA Astrophysics Data System (ADS)

    Sané, Jimaan; Padding, Johan T.; Louis, Ard A.

    2015-09-01

    We use a mesoscopic particle-based simulation technique to study the classic convection-diffusion problem of Taylor dispersion for colloidal discs in confined flow. When the disc diameter becomes non-negligible compared to the diameter of the pipe, there are important corrections to the original Taylor picture. For example, the colloids can flow more rapidly than the underlying fluid, and their Taylor dispersion coefficient is decreased. For narrow pipes, there are also further hydrodynamic wall effects. The long-time tails in the velocity autocorrelation functions are altered by the Poiseuille flow.

  4. 76 FR 18378 - Amendment of Class E Airspace; Taylor, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-04

    ...-1189; Airspace Docket No. 10-AWP-19] Amendment of Class E Airspace; Taylor, AZ AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action will amend Class E airspace at Taylor Airport, Taylor, AZ, to accommodate aircraft using the CAMBO One Departure, and the Area Navigation (RNAV...

  5. Groundwater seeps in Taylor Valley Antarctica: an example of a subsurface melt event

    NASA Astrophysics Data System (ADS)

    Lyons, W. Berry; Welch, Kathleen A.; Carey, Anne E.; Doran, Peter T.; Wall, Diana H.; Virginia, Ross A.; Fountain, Andrew G.; Csathó, Bea M.; Tremper, Catherine M.

    The 2001/02 austral summer was the warmest summer on record in Taylor Valley, Antarctica, (˜78° S) since continuous records of temperature began in 1985. The highest stream-flows ever recorded in the Onyx River, Wright Valley, were also recorded that year (the record goes back to the 1969/70 austral summer). In early January 2002, a groundwater seep was observed flowing in the southwest portion of Taylor Valley. This flow has been named 'Wormherder Creek' (WHC) and represents an unusual event, probably occurring on a decadal time-scale. The physical characteristics of this feature suggest that it may have flowed at other times in the past. Other groundwater seeps, emanating from the north-facing slope of Taylor Valley, were also observed. Little work has been done previously on these very ephemeral seeps, and the source of water is unknown. These features, resembling recently described features on Mars, represent the melting of subsurface ice. The Martian features have been interpreted as groundwater seeps. In this paper we compare the chemistry of the WHC groundwater seep to that of the surrounding streams that flow every austral summer. The total dissolved solids content of WHC was ˜6 times greater than that of some nearby streams. The Na : Cl and SO4 : Cl ratios of the seep waters are higher than those of the streams, but the Mg : Cl and HCO3 : Cl ratios are lower, indicating different sources of solutes to the seeps compared to the streams. The enrichment of Na and SO4 relative to Cl may suggest significant dissolution of mirabilite within the previously unwetted soil. The proposed occurrence of abundant mirabilite in higher-elevation soils of the dry valley region agrees with geochemical models developed, but not tested, in the late 1970s. The geochemical data demonstrate that these seeps could be important in 'rinsing' the soils by dissolving and redistributing the long-term accumulation of salts, and perhaps improving habitat suitability for soil biota

  6. Evidence for an abrupt transition in the mantle-derived source to the Long Valley Caldera rhyolites after the climactic eruption: from subduction-modified lithosphere to asthenosphere

    NASA Astrophysics Data System (ADS)

    Waters, L.; Lange, R. A.

    2014-12-01

    Shortly after the climactic eruption of ~600 km3 of Bishop Tuff zoned rhyolitic magma, ~100 km3 of crystal-poor Early Rhyolite erupted inside Long Valley Caldera between ~750-650 ka as domes, glassy lavas, and tuffs (Hildreth, 2004). Despite similarities in bulk composition (e.g., 73-75 wt% SiO2; ~100 ppm Sr), there are marked differences between the Late (≥ 790°C) Bishop Tuff and postcaldera Early Rhyolites. Although crystal-poor (<5%), the Early Rhyolites are often saturated with 7-8 mineral phases (plag + opx + ilm + tmte + biotite + apatite + zircon ± pyrrhotite), but without the quartz, sanidine, and cpx additionally found in the more crystal-rich (12-24%) Late Bishop Tuff. Pre-eruptive temperatures, on the basis of two Fe-Ti oxides, range from 720-860°C, and ΔNNO values range from-0.4 to -0.9 (consistent with abundant ilmenite). Thus the Early Rhyolites record fO2 values that are nearly two orders of magnitude lower than those in the Late Bishop Tuff (ΔNNO = +1; Hildreth and Wilson, 2007). Application of the plagioclase-liquid hygrometer to Early Rhyolites gives pre-eruptive water contents ≤ 4.4 wt% H2O. The phenocrysts in Early Rhyolite obsidians often display euhedral and/or diffusion-limited growth textures, suggesting degassing-induced crystallization during rapid ascent. Isotopic data from the literature (e.g., Simon et al., 2014 and references therein) show that Long Valley rhyolites were derived from both crustal and mantle sources. We hypothesize that the drop in fO2 between the Late Bishop Tuff and Early Rhyolites may reflect a transition in their respective mantle source, from subduction-modified lithosphere to asthenosphere. Such a time-progressive transition in the mantle source of erupted basalts is seen throughout the Great Basin, occurring earliest in its central region and more recently toward its western margin (e.g. Cousens et al., 2012). Although the geochemistry of Quaternary basalts erupted around Long Valley indicate a

  7. Flood-inundation maps for Indian Creek and Tomahawk Creek, Johnson County, Kansas, 2014

    USGS Publications Warehouse

    Peters, Arin J.; Studley, Seth E.

    2016-01-25

    Digital flood-inundation maps for a 6.4-mile upper reach of Indian Creek from College Boulevard to the confluence with Tomahawk Creek, a 3.9-mile reach of Tomahawk Creek from 127th Street to the confluence with Indian Creek, and a 1.9-mile lower reach of Indian Creek from the confluence with Tomahawk Creek to just beyond the Kansas/Missouri border at State Line Road in Johnson County, Kansas, were created by the U.S. Geological Survey in cooperation with the city of Overland Park, Kansas. The flood-inundation maps, which can be accessed through the U.S. Geological Survey Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the U.S. Geological Survey streamgages on Indian Creek at Overland Park, Kansas; Indian Creek at State Line Road, Leawood, Kansas; and Tomahawk Creek near Overland Park, Kansas. Near real time stages at these streamgages may be obtained on the Web from the U.S. Geological Survey National Water Information System at http://waterdata.usgs.gov/nwis or the National Weather Service Advanced Hydrologic Prediction Service at http://water.weather.gov/ahps/, which also forecasts flood hydrographs at these sites.Flood profiles were computed for the stream reaches by means of a one-dimensional step-backwater model. The model was calibrated for each reach by using the most current stage-discharge relations at the streamgages. The hydraulic models were then used to determine 15 water-surface profiles for Indian Creek at Overland Park, Kansas; 17 water-surface profiles for Indian Creek at State Line Road, Leawood, Kansas; and 14 water-surface profiles for Tomahawk Creek near Overland Park, Kansas, for flood stages at 1-foot intervals referenced to the streamgage datum and ranging from bankfull to the next interval above the 0.2-percent annual exceedance probability flood level (500-year recurrence interval). The

  8. Explosive Eruption of Aphyric Rhyolitic Liquid During May 2008 from Chaitén Volcano, Chile

    NASA Astrophysics Data System (ADS)

    Lowenstern, J. B.; Sisson, T. W.; Pallister, J.; Lara, L.; Muñoz, J.

    2008-12-01

    Rhyolitic liquid erupted as Plinian fallout in May 2008 from Chaitén volcano represents a near-aphyric hydrous melt extracted and erupted rapidly from a source region deeper than at least four kilometers. We studied pumice lumps (to 18 cm) most likely erupted between May 2 and 9 but collected later from a strand line of beach near the port of Chaitén, 30 km south of the volcano. Most lumps have fibrous tube vesicles; the largest lump has a density of 0.80 g/cm3. Crystals compose less than 0.1 vol percent dense-rock equivalent. Rare phenocrysts, 0.5 to 1.0 mm in maximum diameter, are all subhedral and dominated by plagioclase, with lesser ferrohypersthene, amphibole and titanomagnetite. Backscatter imaging of grain mounts also revealed accessory apatite, zircon and pyrrhotite. No microlites were found in the matrix glass from these samples. A whole-rock analysis gives SiO2 = 75.9 wt.%, TiO2 = 0.27, Al2O3 = 13.5, FeOt = 1.30, MnO = 0.05, MgO = 0.27, CaO = 1.43, Na2O = 4.11, K2O= 3.11 and P2O5 = 0.07. Trace-element concentrations indicate that the rhyolite is not highly evolved, with moderate Rb (105 ppm) and U (3.33 ppm), and higher Sr concentrations (153 ppm) than would be typical of highly fractionated liquids. The magma chemical composition is very similar to a rhyolite dome erupted 5.6-9.4 ka at Chaitén (Naranjo and Stern, 2004; Stern et al. 2002). Electron probe analysis shows that plagioclase grains are mainly ~ An40, with rare cores as calcic as An80. Orthopyroxenes are nearly all ~ En50. Amphiboles are far more aluminous than expected for crystals forming from a shallow high-silica rhyolite magma: their Al2O3 ranges from 10.8 to 13.8 wt.%. Though the amphiboles are not euhedral, they also lack marginal reaction rinds or other evidence of breakdown due to decompression and consequent dehydration. We interpret mineral and glass compositions and textures to indicate that the magma was extracted from an intermediate-composition crystal-rich (e.g., 40

  9. H2O in rhyolitic glasses and melts: Measurement, speciation, solubility, and diffusion

    NASA Astrophysics Data System (ADS)

    Zhang, Youxue

    1999-11-01

    Dissolved H2O in silicate melts and glasses plays a crucial role in volcanic eruptions on terrestrial planets and affects glass properties and magma evolution. In this paper, major progress on several aspects of the H2O-melt (or glass) system is reviewed, consistency among a variety of data is investigated, discrepancies are evaluated, and confusion is clarified. On the infrared measurement of total H2O and species concentrations, calibration for a variety of glasses has been carried out at room temperature. The measurements for H2O in rhyolitic glasses have undergone the most scrutiny, resulting in the realization that absorptivities for the near-infrared bands depend on total H2O content. Although the variation of the absorptivities does not seem to significantly affect the determination of total H2O, it does affect the determination of molecular H2O and OH species concentrations. Calibration of the infrared technique for H2O in rhyolitic glasses still needs much improvement, especially at high total H2O. Furthermore, it is now almost certain that the molar absorptivities also depend on the measurement temperature in in situ studies. Hence it will be necessary to carry out calibrations in situ at high temperatures. On H2O speciation, results from two experimental approaches, the quench technique and the in situ technique, are very different, leading to controversy in our understanding of true speciation. A solution is presented to reconcile this controversy. It is almost certain that the quench technique does not suffer from a quench problem, but interpretation of in situ results suffered from ignoring the dependence of the molar absorptivities on measurement temperature. Accurate calibration at high temperatures is necessary for the quantitative application of the in situ technique to H2O speciation in silicate melts and glasses. On H2O solubility in silicate melts, recent experimental work has significantly expanded the T-P range of solubility measurements, and

  10. G.I. Taylor and the Trinity Test

    ERIC Educational Resources Information Center

    Deakin, Michael A. B.

    2011-01-01

    The story is often told of the calculation by G.I. Taylor of the yield of the first ever atomic bomb exploded in New Mexico in 1945. It has indeed become a staple of the classroom whenever dimensional analysis is taught. However, while it is true that Taylor succeeded in calculating this figure at a time when it was still classified, most versions…

  11. Mineral chemistry indicates the petrogenesis of rhyolite from the southwestern Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Chen, Zuxing; Zeng, Zhigang; Wang, Xiaoyuan; Zhang, Yuxiang; Yin, Xuebo; Chen, Shuai; Ma, Yao; Li, Xiaohui; Qi, Hanyan

    2017-12-01

    To reveal the petrogenesis of rhyolite from the southwestern Okinawa Trough, the mineral chemistry of plagioclase, orthopyroxene, amphibole, quartz and Fe-Ti oxide phenocrysts were analyzed using an electron microprobe, and in suit Sr and Ba contents of plagioclase analysed by LA-ICPMS were chosen for fingerprinting plagioclases of different provenances. Results indicate an overall homogeneous composition for each of the mineral phases except for plagioclase phenocrysts which have a wide range of composition (An=39 88). Plagioclase crystals characterized by An contents of >70 are not in equilibrium with their whole-rock compositions, and coarse-sieved plagioclase phenocryst interiors record high An contents (>70) and Sr/Ba ratios (>7), which are similar to the those of plagioclase crystals in basalt. Therefore, these crystals must have been introduced to the rhyolitic magma from a more mafic source. Equilibrium temperatures estimated using orthopyroxene-liquid, iron-titanium oxide, titanium-in-quartz and amphibole geothermometers show consistent values ranging from 792 to 869°C. The equilibrium pressure calculated using amphibole compositions is close to 121 MPa which corresponds to an approximate depth of 4 km. The fO2 conditions estimated from Fe-Ti oxides and amphiboles plot slightly above the NNO buffer, which indicates that the rock formed under more oxidized conditions. Our results suggests that petrogenesis of the rhyolite due to basaltic magma ascend with the high An and Sr/Ba plaigoclases from deep magma chamber into the shallow chamber where the fractional crystallization and crustal assimilation happened. It also indicates that a two-layer magma chamber structure may occur under the southwestern Okinawa Trough.

  12. The unusual mineralogy of the Hayes River rhyolite, Hayes Volcano, Cook Inlet, Alaska

    NASA Astrophysics Data System (ADS)

    Hayden, L. A.; Coombs, M. L.; McHugh, K.

    2013-12-01

    Hayes Volcano is an ice-covered volcanic massif located in the northern Cook Inlet region approximately 135 miles northwest of Anchorage, Alaska. The last major eruptive episode of Hayes, and the only known in any detail, occurred ~3,700 yr B.P. and produced the Hayes Tephra Set H, a series of dacitic fall deposits widespread throughout southcentral Alaska (Riehle et al., 1994, Quat. Res. 33, p. 91-108). An undated, early Holocene pyroclastic-flow deposit exposed beneath Tephra Set H in the Hayes River valley is unusual in the Aleutian-Alaska subduction zone in whole-rock composition and mineralogy. The deposit comprises rhyolite pumice (~75 wt% SiO2) that contain phenocrysts of plagioclase, sanidine, quartz, and biotite in vesicular, clear matrix glass, and <1% dense, white cognate inclusions with the same whole-rock composition and phenocryst assemblage as the pumice, but a crystalline matrix. Holocrystalline inclusions may represent portions of the magma body that rapidly quenched in the shallow subsurface as dikes or chamber rinds and were then excavated during explosive eruption. Rhyolite and inclusions are peraluminous (2-3 % normative corundum), high-K, enriched in incompatible elements, and depleted in Sr and Eu. In accord with its evolved and enriched composition the rhyolite pumice and inclusions contain an abundance of accessory phases, including apatite, monazite, xenotime, and zircon. Monazite are euhedral, as large as 500 um, ThO2-rich (up to 4 wt%) and contain significant amounts of Ag (200-500 ppm). Xenotime are generally smaller than the monazite and occur frequently as small blebs. Rhyolite pumices also contain Fe-sulfides, Cu, Sn, Ni, and barite. Sanidine phenocrysts in the pumice and inclusions are sharply zoned and highly enriched in the celsian component (up to 5 wt% BaO) and also show LREE enrichment. Inclusions contain abundant Mn-rich cordierite (~3 wt% Mn2O3) in the san-plag-qtz matrix, as well as Fe-Ti oxides that are relatively high in

  13. Cathedral house & crocker fence, Taylor Street east and north ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Cathedral house & crocker fence, Taylor Street east and north elevations, perspective view from the northeast - Grace Cathedral, George William Gibbs Memorial Hall, 1051 Taylor Street, San Francisco, San Francisco County, CA

  14. Direct Observation of Rhyolite Magma by Drilling: The Proposed Krafla Magma Drilling Project

    NASA Astrophysics Data System (ADS)

    Eichelberger, J. C.; Sigmundsson, F.; Papale, P.; Markusson, S.; Loughlin, S.

    2014-12-01

    Remarkably, drilling in Landsvirkjun Co.'s geothermal field in Krafla Caldera, Iceland has encountered rhyolite magma or hypersolidus rhyolite at 2.1-2.5 km depth in 3 wells distributed over 3.5 km2, including Iceland Deep Drilling Program's IDDP-1 (Mortensen, 2012). Krafla's most recent rifting and eruption (basalt) episode was 1975-1984; deformation since that time has been simple decay. Apparently rhyolite magma was either emplaced during that episode without itself erupting or quietly evolved in situ within 2-3 decades. Analysis of drill cuttings containing quenched melt from IDDP-1 yielded unprecedented petrologic data (Zierenberg et al, 2012). But interpreting active processes of heat and mass transfer requires knowing spatial variations in physical and chemical characteristics at the margin of the magma body, and that requires retrieving core - a not-inconceivable task. Core quenched in situ in melt up to 1150oC was recovered from Kilauea Iki lava lake, Hawaii by the Magma Energy Project >30 years ago. The site from which IDDP-1 was drilled, and perhaps IDDP-1 itself, may be available to attempt the first-ever coring of rhyolite magma, now proposed as the Krafla Magma Drilling Project (KMDP). KMDP would also include geophysical and geochemical experiments to measure the response of the magma/hydrothermal system to fluid injection and flow tests. Fundamental results will reveal the behavior of magma in the upper crust and coupling between magma and the hydrothermal system. Extreme, sustained thermal power output during flow tests of IDDP-1 suggests operation of a Kilauea-Iki-like freeze-fracture-flow boundary propagating into the magma and mining its latent heat of crystallization (Carrigan et al, EGU, 2014). Such an ultra-hot Enhanced Geothermal System (EGS) might be developable beneath this and other magma-heated conventional hydrothermal systems. Additionally, intra-caldera intrusions like Krafla's are believed to produce the unrest that is so troubling in

  15. Remelting in caldera and rift environments and the genesis of hot, “recycled” rhyolites

    NASA Astrophysics Data System (ADS)

    Simakin, A. G.; Bindeman, I. N.

    2012-07-01

    Large and small volume rhyolites are generated in calderas and rift zones, inheriting older and isotopically diverse crystal populations from their volcanic predecessors. Low-δ18O values in many of these rhyolites suggest that they were derived from the remelting of solid, hydrothermally altered by meteoric water protoliths that were once close to the surface, but become buried by caldera collapse or rifting. These rhyolites persist for millions of years in these environments with little evidence of coeval basalts. We present a series of numerical experiments on convective melting of roof-rocks by the underplated by near liquidus to superheated silicic melts, generated at the base of the chamber by basaltic intrusions in shallow crustal conditions. We used a range of temperatures and compositions, an appropriate phase diagram with a defined extended eutectic zone appropriate for these environments, varied sill thickness, viscosity of the boundary layer, and considered hydrothermal and lower boundary heat losses. The goal was to estimate melting rates and mechanisms, define conditions that are required for efficient and rapid remelting in the upper crust, quantitatively describe novel details of the dynamics of convecting melting, and compare it to the earlier parametric and numerical treatments of roof melting by underplating. Resolution of numerical experiments allowed us to track mixed thermal and two-phase plume-like convection in silicic magma with a bulk viscosity of 104.5-105.5 Pa s. The following results were obtained: (1) remarkably fast melting/magma generation rates of many meters per year, (2) intrinsic inhomogeneities in the roof accelerates convection and melting rates via rapid gravitational settling of refractory blocks and exposing detachment scars to the melting front, (3) due to rapid melting, hydrothermal heat loss through the roof, and conductive heat dissipation through the bottom are less important on melting timescales. (4) Convective

  16. 15. TURNTABLE RECONSTRUCTION BAY & TAYLOR: Photocopy of January ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. TURNTABLE RECONSTRUCTION - BAY & TAYLOR: Photocopy of January 1941 photograph taken during reconstruction of the Bay and Taylor turntable. View to the south. The 'spider' that carries the actual turntable is in place in the pit. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  17. Linear stability of compressible Taylor-Couette flow

    NASA Technical Reports Server (NTRS)

    Kao, Kai-Hsiung; Chow, Chuen-Yen

    1992-01-01

    A temporal stability analysis of compressible Taylor-Couette flow is presented. The viscous flow studied in this paper is contained between two concentric cylinders of infinite length, which are rotating with different angular velocities and are kept at different surface temperatures. The effects of differential rotation and temperature difference on the stability of Taylor-Couette flow are contrasted for a range of Mach numbers ranging from incompressible to Mach 3.0. The relative motion of the cylinders dramatically affects the characteristics of the Couette flow at the onset of instability. The flow is stabilized or destabilized depending upon the temperature ratio and speeds of the two cylinders. Independent of Mach number and temperature ratio, increasing Reynolds number generally promotes a destabilizing effect, indicating the inviscid nature of the Taylor-Couette flow.

  18. 78 FR 62616 - Salmon Creek Hydroelectric Company, Salmon Creek Hydroelectric Company, LLC; Notice of Transfer...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-22

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 3730-005] Salmon Creek Hydroelectric Company, Salmon Creek Hydroelectric Company, LLC; Notice of Transfer of Exemption 1. By letter filed September 23, 2013, Salmon Creek Hydroelectric Company informed the Commission that they have...

  19. Composition and origin of rhyolite melt intersected by drilling in the Krafla geothermal field, Iceland

    USGS Publications Warehouse

    Zierenberg, R.A.; Schiffman, P.; Barfod, G.H.; Lesher, C.E.; Marks, N.E.; Lowenstern, Jacob B.; Mortensen, A.K.; Pope, E.C.; Bird, D.K.; Reed, M.H.; Friðleifsson, G.O.; Elders, W.A.

    2013-01-01

    The Iceland Deep Drilling Project Well 1 was designed as a 4- to 5-km-deep exploration well with the goal of intercepting supercritical hydrothermal fluids in the Krafla geothermal field, Iceland. The well unexpectedly drilled into a high-silica (76.5 % SiO2) rhyolite melt at approximately 2.1 km. Some of the melt vesiculated while extruding into the drill hole, but most of the recovered cuttings are quenched sparsely phyric, vesicle-poor glass. The phenocryst assemblage is comprised of titanomagnetite, plagioclase, augite, and pigeonite. Compositional zoning in plagioclase and exsolution lamellae in augite and pigeonite record changing crystallization conditions as the melt migrated to its present depth of emplacement. The in situ temperature of the melt is estimated to be between 850 and 920 °C based on two-pyroxene geothermometry and modeling of the crystallization sequence. Volatile content of the glass indicated partial degassing at an in situ pressure that is above hydrostatic (~16 MPa) and below lithostatic (~55 MPa). The major element and minor element composition of the melt are consistent with an origin by partial melting of hydrothermally altered basaltic crust at depth, similar to rhyolite erupted within the Krafla Caldera. Chondrite-normalized REE concentrations show strong light REE enrichment and relative flat patterns with negative Eu anomaly. Strontium isotope values (0.70328) are consistent with mantle-derived melt, but oxygen and hydrogen isotope values are depleted (3.1 and −118 ‰, respectively) relative to mantle values. The hydrogen isotope values overlap those of hydrothermal epidote from rocks altered by the meteoric-water-recharged Krafla geothermal system. The rhyolite melt was emplaced into and has reacted with a felsic intrusive suite that has nearly identical composition. The felsite is composed of quartz, alkali feldspar, plagioclase, titanomagnetite, and augite. Emplacement of the rhyolite magma has resulted in partial melting of

  20. Fisheries Aspects of Seamounts and Taylor Columns

    DTIC Science & Technology

    1986-09-01

    the armorhead population. Due to a probable combination of overfishing and poor recruitment, the large fishery of the early 1970’s began a rapid...ACCESSION NO T I TLE (include Security Classification) FISHERIES ASPECTS OF SEAMOUNTS AND TAYLOR COLUMNS 2 PERSONAL AUTHOR(S) Brainard, Russell E. 13a...retention Seamount oceanography Taylor column Fisheries Nutrient enrichment 𔄃 3ASTRACT (Continue on reverse of necessary and identify by block number

  1. Geochemistry, strontium isotope data, and potassium-argon ages of the andesite-rhyolite association in the Padang area, West Sumatra

    USGS Publications Warehouse

    Leo, G.W.; Hedge, C.E.; Marvin, R.F.

    1980-01-01

    Quaternary volcanoes in the Padang area on the west coast of Sumatra have produced two-pyroxene, calc-alkaline andesite and volumetrically subordinate rhyolitic and andesitic ash-flow tuffs. A sequence of andesite (pre-caldera), rhyolitic tuff and andesitic tuff, in decreasing order of age, is related to Maninjau caldera. Andesite compositions range from 55.0 to 61.2% SiO2 and from 1.13 to 2.05% K2O. Six K-Ar whole-rock age determinations on andesites show a range of 0.27 ?? 0.12 to 0.83 ?? 0.42 m.y.; a single determination on the rhyolitic ashflow tuff gave 0.28 ?? 0.12 m.y. Eight 57Sr/26Sr ratios on andesites and rhyolite tuff west of the Semangko fault zone are in the range 0.7056 - 0.7066. These ratios are higher than those elsewhere in the Sunda arc but are comparable to the Taupo volcanic zone of New Zealand and calc-alkaline volcanics of continental margins. An 87Sr/86Sr ratio of 0.7048 on G. Sirabungan east of the Semangko fault is similar to an earlier determination on nearby G. Marapi (0.7047), and agrees with 87Sr/86Sr ratios in the rest of the Sunda arc. The reason for this distribution of 87Sr/86Sr ratios is unknown. The high 87Sr/86Sr ratios are tentatively regarded to reflect a crustal source for the andesites, while moderately fractionated REE patterns with pronounced negative Eu anomalies suggest a residue enriched in plagioclase with hornblende and/or pyroxenes. Generation of associated andesite and rhyolite could have been caused by hydrous fractional melting of andesite or volcanogenic sediments under adiabatic decompression. ?? 1980.

  2. Bright and durable field emission source derived from refractory taylor cones

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hirsch, Gregory

    A method of producing field emitters having improved brightness and durability relying on the creation of a liquid Taylor cone from electrically conductive materials having high melting points. The method calls for melting the end of a wire substrate with a focused laser beam, while imposing a high positive potential on the material. The resulting molten Taylor cone is subsequently rapidly quenched by cessation of the laser power. Rapid quenching is facilitated in large part by radiative cooling, resulting in structures having characteristics closely matching that of the original liquid Taylor cone. Frozen Taylor cones thus obtained yield desirable tipmore » end forms for field emission sources in electron beam applications. Regeneration of the frozen Taylor cones in-situ is readily accomplished by repeating the initial formation procedures. The high temperature liquid Taylor cones can also be employed as bright ion sources with chemical elements previously considered impractical to implement.« less

  3. Magma deformation and emplacement in rhyolitic dykes

    NASA Astrophysics Data System (ADS)

    McGowan, Ellen; Tuffen, Hugh; James, Mike; Wynn, Peter

    2016-04-01

    Silicic eruption mechanisms are determined by the rheological and degassing behaviour of highly-viscous magma ascending within shallow dykes and conduits. However, we have little knowledge of how magmatic behaviour shifts during eruptions as dykes and conduits evolve. To address this we have analysed the micro- to macro-scale textures in shallow, dissected rhyolitic dykes at the Tertiary Húsafell central volcano in west Iceland. Dyke intrusion at ~3 Ma was associated with the emplacement of subaerial rhyolitic pyroclastic deposits following caldera formation[1]. The dykes are dissected to ~500 m depth, 2-3 m wide, and crop out in two stream valleys with 5-30 m-long exposures. Dykes intrude diverse country rock types, including a welded ignimbrite, basaltic lavas, and glacial conglomerate. Each of the six studied dykes is broadly similar, exhibiting obsidian margins and microcrystalline cores. Dykes within pre-fractured lava are surrounded by external tuffisite vein networks, which are absent from dykes within conglomerate, whereas dykes failed to penetrate the ignimbrite. Obsidian at dyke margins comprises layers of discrete colour. These display dramatic thickness variations and collapsed bubble structures, and are locally separated by zones of welded, brecciated and flow-banded obsidian. We use textural associations to present a detailed model of dyke emplacement and evolution. Dykes initially propagated with the passage of fragmented, gas-charged magma and generation of external tuffisite veins, whose distribution was strongly influenced by pre-existing fractures in the country rock. External tuffisites retained permeability throughout dyke emplacement due to their high lithic content. The geochemically homogenous dykes then evolved via incremental magma emplacement, with shear deformation localised along emplacement boundary layers. Shear zones migrated between different boundary layers, and bubble deformation promoted magma mobility. Brittle

  4. The Early Oligocene Copperas Creek Volcano and geology along New Mexico Higway 15 between Sapillo Creek and the Gila Cliff Dwellings National Monument, Grant and Catron Counties, New Mexico

    USGS Publications Warehouse

    Ratté, James C.; Mack, Greg; Witcher, James; Lueth, Virgil W.

    2008-01-01

    The section of New Mexico Highway 15 between the intersection of NM-15 and NM 35 (aka Sapillo junction) at the south and the Gila Cliff Dwellings National Monument at the north end of NM –15 occupies an approximately 18 mile long, mile wide, corridor through the eastern part of the Gila Wilderness (Fig. 1). Whereas most of the Gila Wilderness is dominated by silicic, caldera-forming supervolcanoes of Eocene to Oligocene age, this part of NM-15 traverses a volcanic terrain of similar age, but composed mainly of intermediate composition lava flows and minor associated rhyolitic intrusions and pyroclastic rocks, which are related to the here-named Copperas Creek volcano. This volcanic complex is bounded by Basin and Range structures: on the south by the Sapillo Creek graben, and on the north by the Gila Hot Springs graben, both of which are filled with Gila Conglomerate of late Tertiary to Pleistocene(?) age. Hot springs in the Gila River valley are localized along faults in the deepest part of the Gila Hot Springs graben. The cliff dwellings of the National Monument were constructed in caves in Gila Conglomerate in the western part of the Gila Hot Springs graben. The eastern edge of the Gila Cliff Dwellings caldera is buried by younger rocks east of the cliff dwellings, but spectacular cliffs of Bloodgood Canyon Tuff, which fills the caldera, can be viewed along the West Fork of the Gila River from the trail starting at the cliff dwellings. Although this is not intended as a formal road log, highway mileage markers (MM) will be used to locate geologic features more or less progressively from south to north along NM-15.

  5. Lead and strontium isotopic evidence for crustal interaction and compositional zonation in the source regions of Pleistocene basaltic and rhyolitic magmas of the Coso volcanic field, California

    USGS Publications Warehouse

    Bacon, C.R.; Kurasawa, H.; Delevaux, M.H.; Kistler, R.W.; Doe, B.R.

    1984-01-01

    The isotopic compositions of Pb and Sr in Pleistocene basalt, high-silica rhyolite, and andesitic inclusions in rhyolite of the Coso volcanic field indicate that these rocks were derived from different levels of compositionally zoned magmatic systems. The 2 earliest rhyolites probably were tapped from short-lived silicic reservoirs, in contrast to the other 36 rhyolite domes and lava flows which the isotopic data suggest may have been leaked from the top of a single, long-lived magmatic system. Most Coso basalts show isotopic, geochemical, and mineralogic evidence of interaction with crustal rocks, but one analyzed flow has isotopic ratios that may represent mantle values (87Sr/86Sr=0.7036,206Pb/204Pb=19.05,207Pb/204Pb=15.62,208Pb/204Pb= 38.63). The (initial) isotopic composition of typical rhyolite (87Sr/86Sr=0.7053,206Pb/204Pb=19.29,207Pb/204Pb= 15.68,208Pb/204Pb=39.00) is representative of the middle or upper crust. Andesitic inclusions in the rhyolites are evidently samples of hybrid magmas from the silicic/mafic interface in vertically zoned magma reservoirs. Silicic end-member compositions inferred for these mixed magmas, however, are not those of erupted rhyolite but reflect the zonation within the silicic part of the magma reservoir. The compositional contrast at the interface between mafic and silicic parts of these systems apparently was greater for the earlier, smaller reservoirs. ?? 1984 Springer-Verlag.

  6. Centrifugally Driven Rayleigh-Taylor Instability

    NASA Astrophysics Data System (ADS)

    Scase, Matthew; Hill, Richard

    2017-11-01

    The instability that develops at the interface between two fluids of differing density due to the rapid rotation of the system may be considered as a limit of high-rotation rate Rayleigh-Taylor instability. Previously the authors have considered the effect of rotation on a gravitationally dominated Rayleigh-Taylor instability and have shown that some growth modes of instability may be suppressed completely by the stabilizing effect of rotation (Phys. Rev. Fluids 2:024801, Sci. Rep. 5:11706). Here we consider the case of very high rotation rates and a negligible gravitational field. The initial condition is of a dense inner cylinder of fluid surrounded by a lighter layer of fluid. As the system is rotated about the generating axis of the cylinder, the dense inner fluid moves away from the axis and the familiar bubbles and spikes of Rayleigh-Taylor instability develop at the interface. The system may be thought of as a ``fluid-fluid centrifuge''. By developing a model based on an Orr-Sommerfeld equation, we consider the effects of viscosity, surface tension and interface diffusion on the growth rate and modes of instability. We show that under particular circumstances some modes may be stabilized. School of Mathematical Sciences.

  7. Shell Creek Summers

    ERIC Educational Resources Information Center

    Seier, Mark; Goedeken, Suzy

    2005-01-01

    In 2002 Shell Creek Watershed Improvement Group turned to the Newman Grove Public Schools' science department to help educate the public on water quality in the watershed and to establish a monitoring system that would be used to improve surface and groundwater quality in the creek's watershed. Nebraska Department of Environmental Quality provided…

  8. 76 FR 35379 - Archers Creek, Ribbon Creek, and Broad River; U.S. Marine Corps Recruit Depot, Parris Island, SC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-17

    ..., Ribbon Creek, and Broad River; U.S. Marine Corps Recruit Depot, Parris Island, SC; Danger Zone AGENCY... use these portions of Archers Creek, Ribbon Creek, and the Broad River when the rifle and pistol.... 334.480 to read as follows: Sec. 334.480 Archers Creek, Ribbon Creek, and Broad River; U.S. Marine...

  9. Animating Nested Taylor Polynomials to Approximate a Function

    ERIC Educational Resources Information Center

    Mazzone, Eric F.; Piper, Bruce R.

    2010-01-01

    The way that Taylor polynomials approximate functions can be demonstrated by moving the center point while keeping the degree fixed. These animations are particularly nice when the Taylor polynomials do not intersect and form a nested family. We prove a result that shows when this nesting occurs. The animations can be shown in class or…

  10. Water flow statistics: SRP creeks

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lower, M.W.

    1982-08-26

    For a number of environmental studies it is necessary to know the water flow rates and variations in the SRP streams. The objective of this memorandum is to pull together and present a number of statistical analyses for Upper Three Runs Creek, Four Mile Creek and Lower Three Runs Creek. The data basis covers 8 USGS stream gage stations for the years 1972 - 1981. The average flow rates over a ten-year period along Upper Three Runs Creek were determined to be 114 cfs at US Route 278, 193 cfs at Road C, and 265 cfs at Road A. Alongmore » Four Mile Creek the average flow rates over a ten-year period doubled from 9 cfs prior to F-Area discharges to 18 cfs prior to cooling water discharges from C-Area Reactor. Finally, average flow rates along Lower Three Runs Creek over a ten-year period tripled from 32 cfs at Par Pond to 96 cfs near Snelling, South Carolina. 1 figure, 9 tables.« less

  11. Water quality in Gaines Creek and Gaines Creek arm of Eufaula Lake, Oklahoma

    USGS Publications Warehouse

    Kurklin, J.K.

    1990-01-01

    Based on samples collected from May 1978 to May 1980 and analyzed for major anions, nitrogen, trace elements, phytoplankton, and bacteria, the water in Gaines Creek and the Gaines Creek arm of Eufaula Lake was similar with respect to suitability for municipal use. Water from Gaines Creek had a pH range of 5.7 to 7.6 and a maximum specific conductance of 97 microsiemens per centimeter at 25o Celsius, whereas water from the Gaines Creek arm of Eufaula Lake had a pH range of 6.0 to 9.2 and a maximum specific conductance of 260 microsiemens per centimeter at 25o Celsius. Dissolved oxygen, pH, temperature, and specific conductance values for the lake varied with depth. With the exceptions of cadmium, iron, lead, and manganese, trace-element determinations of samples were within recommended national primary and secondary drinking-water standards. When compared to the National Academy of Sciences water-quality criteria, phytoplankton and bacteria counts exceeded recommendations; however, water from either Gaines Creek or Eufaula Lake could be treated similarly and used as a municipal water supply.

  12. Comments on Some Phanerozoic Batholiths, Ignimbrites, f- Rhyolites

    NASA Astrophysics Data System (ADS)

    Obenholzner, J. H.

    2007-05-01

    Mesozoic and Paleozoic ignimbrites and tuffs might support rejuvenation of batholiths as zircon dating caused in many cases a discrepancy between the inferred eruption age derived from zircon ages and the age of +/- time- equivalent fossils. Such age discrepancies exist in the range of several to more than 10 my i.e. tuffs within Permian beds (Königer et al.. 2002) and Blasseneck-Porphyroid ignimbrites (BPIs) - (Söllner et al. 1997). The BPIs (ca. Ord. VI) are exposed along ca. 300 km in the E Alps. Compacted thicknesses are max. 600 m at lower greenschist-facies. It is not determined yet if the BPIs represent a silicic LIP (1 pulse volcanism(?)). They are underlain by sediments and km-thick (flood?) basalts of lower Ord. age. The BPIs predate the Hirnantian glaciation. The end of zircon growth could also be interpreted as the age of the batholith emplacement. Rejuvenation did not cause further zircon growth. Zircons of Trias. ignimbrites (Obenholzner et al. 1999) showed a broad set of preservation from euhedral to highly corroded during diagenesis (see also Reddy et al. (2006)). Within the realm of Variscean batholiths of Cornwall and Erzgebirge F-rich rhyolites exist which are interpreted as late-stage fractionation or as products of an independent magmatic event. These rhyolites are ca. 20 m.y. younger than the associated granites and intruded or erupted at the very end of the subduction. The Cret. Lost River granite is characterized by distinctive greisenization events (Sainsbury, 1960) and intra-intrusive breccias (Dobson, 1982). In the Erzgebirge explosion breccias exist within the granite (Kempe et al., 2004). Does it represent an episode of rejuvenation including zircon growth? If the time gap of ca. 20 m.y. can be considered an average the F-rhyolites of the Sierra Madre Occidental (Orozco-Esquirel et al., 2002) might be related to batholith emplacement older than the ignimbrite-forming batholiths. The Variscean batholiths of the E Alps host many

  13. Quality of water and time-of-travel in Bakers Creek near Clinton, Mississippi. [Bakers Creek

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kalkhoff, S.J.

    1982-01-01

    A short-term intensive quality-of-water study was conducted during a period of generally low streamflow in Bakers Creek and its tributary, Lindsey Creek, near Clinton, Mississippi. During the September 15-18, 1980 study, dissolved oxygen concentrations in Bakers Creek were less than 5 milligrams per liter. The specific conductance, 5-day biochemical oxygen demand, nutrient concentrations, and bacteria densities in Bakers Creek decreased downstream through the study reach. The mean specific conductance decreased from 670 to 306 microhms per centimeter. The 5-day biochemical oxygen demand decreased from 19 to 2.8 milligrams per liter. The mean total nitrogen and phosphorous concentrations decreased from 10more » and 7.1 to 1.0 and 0.87 milligram per litter, respectively. The maximum fecal bacteria decreased from 7200 to 400 colonies per 100 milliliter. The concentrations of mercury, iron, and manganese in a sample collected at the downstream site exceeded recommended limits. Diazinon and 2,4-D were also present in the water. A bottom material sample contained DDD (2.5 micrograms per kilogram), DDE (2.7 micrograms per kilogram), and DDT (.3 micrograms per kilogram). The tributary inflow from Lindsey Creek did not improve the water quality of Bakers Creek. The dissolved oxygen concentrations were generally less than 5.0 milligrams per liter at the sampling site on Lindsey Creek. The 5-day biochemical oxygen demand, the mean specific conductance, and fecal coliform densities were greater in the tributary than at the downstream site on Bakers Creek. The average rate of travel through a 1.8-mile reach of Bakers Creek was 0.06 foot per second or 0.04 miles per hour. 6 references, 9 figures, 2 tables.« less

  14. Uranium mobility during interaction of rhyolitic glass with alkaline solutions: dissolution of glass

    USGS Publications Warehouse

    Zielinski, Robert A.

    1977-01-01

    This report concerns investigations designed to identify the important physical and chemical parameters influencing the rate of release of uranium from glass shards of rhyolitic air-fall ash. Oxidizing, silica undersaturated, alkaline solutions are eluted through a column of rhyolitic glass shards at a carefully controlled temperature, pressure, and flow rate. The solutions are monitored for the concentration of uranium and selected additional elements (Si, K, Li, F), and the glass is recovered and examined for physical and/or chemical evidence of attack. The flushing mode is designed to mimic leaching of glass shards by intermittent, near-surface waters with which the glass is not in equilibrium. Reported rates are applicable only to the experimental conditions (120?C, 7,000 psi), but it is assumed that the reaction mechanisms and the relative importance of rate-influencing parameters remain unchanged, at reduced temperature and pressure. Results of the above experiment indicate that silica and uranium are released from glass shards at comparable rates, while lithium and potassium are released faster and fluorine slower than either Si or U. Rates of release of silica and uranium correlate positively with the surface area of the shards. Rhyolitic shards release uranium at faster rates than rhyodacitic shards of comparable surface area. Changes in the shards resulting from experimental treatment and observed in the original glass separates from an Oligocene ash (compared to a Pleistocene ash) include; surface pitting, increased surface area, devitrification rinds (<1l micron wide) and reduced lithium contents. Future investigations will study the effect of temperature, pressure, solution composition, and flow rate on the relative mobility of U, Si, Li, F, and K.

  15. Tectonomagmatic significance of the picrite-rhyolite volcanism in the Northern Ethiopian plateau area

    NASA Astrophysics Data System (ADS)

    Natali, Claudio; Beccaluva, Luigi; Bianchini, Gianluca; Siena, Franca

    2010-05-01

    The Oligocene Continental Flood Basalts (CFB) of the Northern Ethiopia and the conjugate Yemen province testifies a huge volcanic event related to the "Afar plume" occurred at ca. 30 Ma (in 1 Ma or less; Hofmann et al., 1997) prior to the continental rifting stage. The zonal arrangement of CFB lavas with Low-Ti tholeiites (LT) in the west, High-Ti tholeiites (HT1) to the east and very High-Ti transitional basalts and picrites (HT2, TiO2 4-6 wt%) closer to the Afar triple junction has been considered a record of magmas generated from the flanks to the centre of a plume head, currently corresponding to the Afar hotspot (Beccaluva et al., 2009). In the central-eastern part of the plateau (Lalibela area), neighbouring the Afar escarpment, abundant rhyolites characterize the upper part of the volcanic sequence and have been interpreted as the differentiated products of CFB magmas (Ayalew et al., 2006). The unusual association of picrite and rhyolite magmas erupted in an elongated area, parallel to the Afar escarpment, appears to be related to peculiar tectonomagmatic events developed in the apical zone of a stretched lithosphere impinged by a mantle plume. As previously suggested, the HT basaltic and picritic magmas could have been generated in the innermost part (core) of the plume head from the hottest, deepest and most metasomatised mantle domains, enriched by "plume components" (Beccaluva et al., 2009). The late stages of these magmatic events were accompanied by the onset of continental rifting, with faulting and block tilting, leading to favourable conditions for magma differentiation in shallow (crustal) chambers located N-S along the future Afar Escarpment. Quantitative petrological modelling shows that efficient fractional crystallization processes of HT transitional basaltic magmas could result in highly differentiated peralkaline rhyolitic products, generally localized at the top (lower density) of the magma reservoirs. From these latter, abundant rhyolitic

  16. High Speed Solution of Spacecraft Trajectory Problems Using Taylor Series Integration

    NASA Technical Reports Server (NTRS)

    Scott, James R.; Martini, Michael C.

    2008-01-01

    Taylor series integration is implemented in a spacecraft trajectory analysis code-the Spacecraft N-body Analysis Program (SNAP) - and compared with the code s existing eighth-order Runge-Kutta Fehlberg time integration scheme. Nine trajectory problems, including near Earth, lunar, Mars and Europa missions, are analyzed. Head-to-head comparison at five different error tolerances shows that, on average, Taylor series is faster than Runge-Kutta Fehlberg by a factor of 15.8. Results further show that Taylor series has superior convergence properties. Taylor series integration proves that it can provide rapid, highly accurate solutions to spacecraft trajectory problems.

  17. Mineralogy and crystallization history of a highly differentiated REE-enriched hypabyssal rhyolite: Round Top laccolith, Trans-Pecos, Texas

    NASA Astrophysics Data System (ADS)

    O'Neill, L. Christine; Elliott, Brent A.; Kyle, J. Richard

    2017-09-01

    The Round Top hypabyssal rhyolite laccolith is a highly evolved magmatic system, enriched in incompatible elements including REE [Rare Earth Element(s)], U, Be, and F. The Round Top intrusion is part of a series of Paleogene intrusions emplaced as the Sierra Blanca Complex. These intrusions are situated within long-lived, complex tectonic regimes that have been subjected to regional compression and subduction, punctuated by extensional bimodal volcanism. The enrichment in the rhyolite that comprises Round Top is the result of the prolonged removal of compatible elements from the source magma chamber through the emplacement of earlier magmatic events. With the emplacement of each sequential laccolith, the F-rich source magma became more enriched in incompatible elements, with increasing HREE [Heavy Rare Earth Elements(s)] concentrations. The emplacement of Round Top as a laccolith (versus that of an extrusive rhyolitic flow) facilitated the retention of the volatile-rich vapor phase within the magma, forming ubiquitous REE-bearing minerals, mainly yttrofluorite and yttrocerite. The high temperature mineral-vapor phase alteration of the feldspar groundmass was essential to the formation of REE minerals, where the pervasive open pore space was occupied by the late-crystallizing minerals. These late-forming REE-bearing minerals also occur as crystals associated with other accessory and trace phases, as inclusions within other phases, along grain boundaries, and along fractures and within voids. The rhyolite at Round Top and other laccolith intrusions in the Sierra Blanca Complex represent a new sub-type of magmatic rare earth element hosting system.

  18. Late Jurassic rhyolites from the Wuchagou region in the central Great Xing'an Range, NE China: Petrogenesis and tectonic implications

    NASA Astrophysics Data System (ADS)

    Ji, Zheng; Ge, Wen-Chun; Yang, Hao; Wang, Qing-hai; Zhang, Yan-long; Wang, Zhi-hui; Bi, Jun-Hui

    2018-06-01

    We report geochronological, whole-rock geochemical, and zircon Hf isotopic data for Late Jurassic rhyolites in the central Great Xing'an Range of northeastern China, to determine their petrogenesis, source, and tectonic setting. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U-Pb ages indicate that the rhyolites previously mapped as the lower Permian Dashizhai Formation in the Wuchagou region formed during the Late Jurassic (162-154 Ma). Geochemically, these rhyolites belong to the mid- to high-K calc-alkaline series and show peraluminous characteristics and consistent correlations between major elements and SiO2. They are characterized by enrichments in large ion lithophile elements (LILEs; e.g., Rb and K) and light rare earth elements (LREEs), and depletions in high field strength elements (HFSEs; e.g., Nb, Ta, and Ti) and heavy rare earth elements (HREEs). In situ Hf isotopic analyses of zircons from the rhyolites reveal relatively homogeneous Hf isotopic compositions, with εHf(t) values of +4.84 to +9.44, and two-stage model ages of 606-895 Ma. Based on their eruption ages, geochemical characteristics, and Hf isotopic compositions, we conclude that the magmas that formed the Late Jurassic rhyolites were produced during partial melting of a Neoproterozoic quartz-bearing amphibolite-facies mafic crust. These magmas subsequently underwent extensive fractional crystallization of plagioclase, hornblende, Ti-bearing phases, monazite, and apatite. Combined with previous data, our results demonstrate that the Late Jurassic volcanic rocks in the Great Xing'an Range were formed in a post-collisional extensional setting. The gravitational collapse of the orogenically thickened crust was caused by break-off of the subducted oceanic slab and upwelling of asthenosphere after closure of the Mongol-Okhotsk Ocean.

  19. Techniques for optimizing nanotips derived from frozen taylor cones

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hirsch, Gregory

    Optimization techniques are disclosed for producing sharp and stable tips/nanotips relying on liquid Taylor cones created from electrically conductive materials with high melting points. A wire substrate of such a material with a preform end in the shape of a regular or concave cone, is first melted with a focused laser beam. Under the influence of a high positive potential, a Taylor cone in a liquid/molten state is formed at that end. The cone is then quenched upon cessation of the laser power, thus freezing the Taylor cone. The tip of the frozen Taylor cone is reheated by the lasermore » to allow its precise localized melting and shaping. Tips thus obtained yield desirable end-forms suitable as electron field emission sources for a variety of applications. In-situ regeneration of the tip is readily accomplished. These tips can also be employed as regenerable bright ion sources using field ionization/desorption of introduced chemical species.« less

  20. Dynamic stabilization of classical Rayleigh-Taylor instability

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Piriz, A. R.; Piriz, S. A.; Tahir, N. A.

    2011-09-15

    Dynamic stabilization of classical Rayleigh-Taylor instability is studied by modeling the interface vibration with the simplest possible wave form, namely, a sequence of Dirac deltas. As expected, stabilization results to be impossible. However, in contradiction to previously reported results obtained with a sinusoidal driving, it is found that in general the perturbation amplitude is larger than in the classical case. Therefore, no beneficial effect can be obtained from the vertical vibration of a Rayleigh-Taylor unstable interface between two ideal fluids.

  1. Hydrology and Flood Profiles of Duck Creek and Jordan Creek Downstream from Egan Drive, Juneau, Alaska

    USGS Publications Warehouse

    Curran, Janet H.

    2007-01-01

    Hydrologic and hydraulic updates for Duck Creek and the lower part of Jordan Creek in Juneau, Alaska, included computation of new estimates of peak streamflow magnitudes and new water-surface profiles for the 10-, 50-, 100-, and 500-year floods. Computations for the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence interval flood magnitudes for both streams used data from U.S. Geological Survey stream-gaging stations weighted with regional regression equations for southeast Alaska. The study area for the hydraulic model consisted of three channels: Duck Creek from Taku Boulevard near the stream's headwaters to Radcliffe Road near the end of the Juneau International Airport runway, an unnamed tributary to Duck Creek from Valley Boulevard to its confluence with Duck Creek, and Jordan Creek from a pedestrian bridge upstream from Egan Drive to Crest Street at Juneau International Airport. Field surveys throughout the study area provided channel geometry for 206 cross sections, and geometric and hydraulic characteristics for 29 culverts and 15 roadway, driveway, or pedestrian bridges. Hydraulic modeling consisted of application of the U.S. Army Corps of Engineers' Hydrologic Engineering Center River Analysis System (HEC-RAS) for steady-state flow at the selected recurrence intervals using an assumed high tide of 20 feet and roughness coefficients refined by calibration to measured water-surface elevations from a 2- to 5-year flood that occurred on November 21, 2005. Model simulation results identify inter-basin flow from Jordan Creek to the southeast at Egan Drive and from Duck Creek to Jordan Creek downstream from Egan Drive at selected recurrence intervals.

  2. Fluid-structure interaction in Taylor-Couette flow

    NASA Astrophysics Data System (ADS)

    Kempf, Martin Horst Willi

    1998-10-01

    The linear stability of a viscous fluid between two concentric, rotating cylinders is considered. The inner cylinder is a rigid boundary and the outer cylinder has an elastic layer exposed to the fluid. The subject is motivated by flow between two adjoining rollers in a printing press. The governing equations of the fluid layer are the incompressible Navier-Stokes equations, and the governing equations of the elastic layer are Navier's equations. A narrow gap, neutral stability, and axisymmetric disturbances are assumed. The solution involves a novel technique for treating two layer stability problems, where an exact solution in the elastic layer is used to isolate the problem in the fluid layer. The results show that the presence of the elastic layer has only a slight effect on the critical Taylor numbers for the elastic parameters of modern printing presses. However, there are parameter values where the critical Taylor number is dramatically different than the classical Taylor-Couette problem.

  3. PREFACE: The 15th International Couette-Taylor Worskhop

    NASA Astrophysics Data System (ADS)

    Mutabazi, Innocent; Crumeyrolle, Olivier

    2008-07-01

    The 15th International Couette-Taylor Worskhop (ICTW15) was held in Le Havre, France from 9-12 July 2007. This regular international conference started in 1979 in Leeds, UK when the research interest in simple models of fluid flows was revitalized by systematic investigation of Rayleigh-Bénard convection and the Couette-Taylor flow. These two flow systems are good prototypes for the study of the transition to chaos and turbulence in closed flows. The workshop themes have been expanded from the original Couette-Taylor flow to include other centrifugal instabilities (Dean, Görtler, Taylor-Dean), spherical Couette flows, thermal convection instabilities, MHD, nonlinear dynamics and chaos, transition to turbulence, development of numerical and experimental techniques. The impressive longevity of the ICTW is due to the close interaction and fertile exchanges between international research groups from different disciplines: Physics and Astrophysics, Applied Mathematics, Mechanical Engineering, Chemical Engineering. The present workshop was attended by 100 participants, the program included over 83 contributions with 4 plenary lectures, 68 oral communications and 17 posters. The topics include, besides the classical Couette-Taylor flows, the centrifugal flows with longitudinal vortices, the shear flows, the thermal convection in curved geometries, the spherical Couette-Taylor flow, the geophysical flows, the magneto-hydrodynamic effects including the dynamo effect, the complex flows (viscoelasticity, immiscible fluids, bubbles and migration). Selected papers have been processed through the peer review system and are published in this issue of the Journal of Physics: Conference Series. The Workshop has been sponsored by Le Havre University, the Region Council of Haute-Normandie, Le Havre City Council, CNRS (ST2I, GdR-DYCOEC), and the European Space Agency through GEOFLOW program. The French Ministry of Defense (DGA), the Ministry of Foreign Affairs, the Ministry of

  4. DSM-5 and ADHD - an interview with Eric Taylor.

    PubMed

    Taylor, Eric

    2013-09-12

    In this podcast we talk to Prof Eric Taylor about the changes to the diagnosis of Attention Deficit Hyperactivity Disorder (ADHD) in DSM-5 and how these changes will affect clinical practice. The podcast for this interview is available at: http://www.biomedcentral.com/sites/2999/download/Taylor.mp3.

  5. 33 CFR 334.480 - Archers Creek, Ribbon Creek, and Broad River; U.S. Marine Corps Recruit Depot, Parris Island...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Broad River; U.S. Marine Corps Recruit Depot, Parris Island, South Carolina; danger zones. 334.480... DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.480 Archers Creek, Ribbon Creek, and Broad River... danger zone on Archers Creek (between the Broad River and Beaufort River), Ribbon Creek, and the Broad...

  6. 33 CFR 334.480 - Archers Creek, Ribbon Creek, and Broad River; U.S. Marine Corps Recruit Depot, Parris Island...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Broad River; U.S. Marine Corps Recruit Depot, Parris Island, South Carolina; danger zones. 334.480... DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.480 Archers Creek, Ribbon Creek, and Broad River... danger zone on Archers Creek (between the Broad River and Beaufort River), Ribbon Creek, and the Broad...

  7. 33 CFR 334.480 - Archers Creek, Ribbon Creek, and Broad River; U.S. Marine Corps Recruit Depot, Parris Island...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Broad River; U.S. Marine Corps Recruit Depot, Parris Island, South Carolina; danger zones. 334.480... DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.480 Archers Creek, Ribbon Creek, and Broad River... danger zone on Archers Creek (between the Broad River and Beaufort River), Ribbon Creek, and the Broad...

  8. A litmus test for exploitation: James Stacey Taylor's stakes and kidneys.

    PubMed

    Kuntz, J R

    2009-12-01

    James Stacy Taylor advances a thorough argument for the legalization of markets in current (live) human kidneys. The market is seemly the most abhorrent type of market, a market where the least well-off sell part of their body to the most well off. Though rigorously defended overall, his arguments concerning exploitation are thin. I examine a number of prominent bioethicists' account of exploitation: most importantly, Ruth Sample's exploitation as degradation. I do so in the context of Taylor's argument, with the aim of buttressing Taylor's position that a regulated kidney market is morally allowable. I argue that Sample fails to provide normative grounds consistent with her claim that exploitation is wrong. I then reformulate her account for consistency and plausibility. Still, this seemingly more plausible view does not show that Taylor's regulated kidney market is prohibitively exploitative of impoverished persons. I tack into place one more piece of support for Taylor's conclusion. (wc. 148).

  9. Jupiter's great red spot revisited. [validity of Taylor column theory

    NASA Technical Reports Server (NTRS)

    Hide, R.

    1972-01-01

    On the original Taylor column theory of Jupiter's Great Red Spot, the fixed latitude of the Spot is taken to imply that the Taylor column in Jupiter's atmosphere is associated with a disturbance such as a topographic feature of the surface Q underlying the atmosphere. The alternative suggestion that the Taylor column is produced by a solid raft floating at depth in the atmosphere is somewhat easier to reconcile with the approximately 10s difference between the respective rotation periods P sub S and P sub R of the Red Spot and of the radio sources, but it does not account so readily for the fixed latitude of the Spot unless it can be shown that the raft is in stable equilibrium under the north-south components of the dynamical forces, including wind effects, acting upon it. A slight wavering of the upper end of the Taylor column relative to the lower end could account at least in part for the most rapid variations in P sub S, but the slow large-amplitude variations in P sub S must reflect changes in the longitudinal motion of either the surface Q or of the raft. By generalizing the Proudman-Taylor theorem to the case of a non-homogeneous fluid it is shown that the Taylor column theory does not imply very special and therefore unlikely horizontal and vertical temperature variations in Jupiter's atmosphere, thus refuting a widely-held belief to the contrary.

  10. 33 CFR 117.331 - Snake Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Snake Creek. 117.331 Section 117.331 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.331 Snake Creek. The draw of the Snake Creek...

  11. Selected hydrologic data for Fountain Creek and Monument Creek basins, east-central Colorado

    USGS Publications Warehouse

    Kuhn, Gerhard; Ortiz, Roderick F.

    1989-01-01

    Selected hydrologic data were collected during 1986, 1987, and 1988 by the U.S. Geological Survey for the Fountain Creek and Monument Creek basins, east-central Colorado. The data were obtained as part of a study to determine the present and projected effects of wastewater discharges on the two creeks. The data, which are available for 129 surface-water sites, include: (1) About 1,100 water quality analyses; (2) about 420 measurements of discharge, (3) characteristics of about 50 dye clouds associated with measurements of traveltime and reaeration , and (4) about 360 measurements of channel geometry. (USGS)

  12. 78 FR 5798 - Grouse Creek Wind Park, LLC, Grouse Creek Wind Park II, LLC; Notice of Petition for Enforcement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-28

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket Nos. El13-39-000, QF11-32-001, QF11-33-001] Grouse Creek Wind Park, LLC, Grouse Creek Wind Park II, LLC; Notice of Petition for... Policies Act of 1978 (PURPA), Grouse Creek Wind Park, LLC and Grouse Creek Wind Park II, LLC filed a...

  13. G.I. Taylor and the Trinity test

    NASA Astrophysics Data System (ADS)

    Deakin, Michael A. B.

    2011-12-01

    The story is often told of the calculation by G.I. Taylor of the yield of the first ever atomic bomb exploded in New Mexico in 1945. It has indeed become a staple of the classroom whenever dimensional analysis is taught. However, while it is true that Taylor succeeded in calculating this figure at a time when it was still classified, most versions of the story are quite inaccurate historically. The reality is more complex than the usual accounts have it. This article sets out to disentangle fact from fiction.

  14. The numerical solution of ordinary differential equations by the Taylor series method

    NASA Technical Reports Server (NTRS)

    Silver, A. H.; Sullivan, E.

    1973-01-01

    A programming implementation of the Taylor series method is presented for solving ordinary differential equations. The compiler is written in PL/1, and the target language is FORTRAN IV. The reduction of a differential system to rational form is described along with the procedures required for automatic numerical integration. The Taylor method is compared with two other methods for a number of differential equations. Algorithms using the Taylor method to find the zeroes of a given differential equation and to evaluate partial derivatives are presented. An annotated listing of the PL/1 program which performs the reduction and code generation is given. Listings of the FORTRAN routines used by the Taylor series method are included along with a compilation of all the recurrence formulas used to generate the Taylor coefficients for non-rational functions.

  15. Distribution of glacial deposits, soils, and permafrost in Taylor Valley, Antarctica

    USGS Publications Warehouse

    Bockheim, James G.; Prentice, M.L.; McLeod, M.

    2008-01-01

    We provide a map of lower and central Taylor Valley, Antarctica, that shows deposits from Taylor Glacier, local alpine glaciers, and grounded ice in the Ross Embayment. From our electronic database, which includes 153 sites from the coast 50 km upvalley to Pearse Valley, we show the distribution of permafrost type and soil subgroups according to Soil Taxonomy. Soils in eastern Taylor Valley are of late Pleistocene age, cryoturbated due to the presence of ground ice or ice-cemented permafrost within 70 cm of the surface, and classified as Glacic and Typic Haploturbels. In central Taylor Valley, soils are dominantly Typic Anhyorthels of mid-Pleistocene age that have dry-frozen permafrost within the upper 70 cm. Salt-enriched soils (Salic Anhyorthels and Petrosalic Anhyorthels) are of limited extent in Taylor Valley and occur primarily on drifts of early Pleistocene and Pliocene age. Soils are less developed in Taylor Valley than in nearby Wright Valley, because of lesser salt input from atmospheric deposition and salt weathering. Ice-cemented permafrost is ubiquitous on Ross Sea, pre-Ross Sea, and Bonney drifts that occur within 28 km of the McMurdo coast. In contrast, dry-frozen permafrost is prevalent on older (???115 ky) surfaces to the west. ?? 2008 Regents of the University of Colorado.

  16. Magnetically Induced Rotating Rayleigh-Taylor Instability.

    PubMed

    Scase, Matthew M; Baldwin, Kyle A; Hill, Richard J A

    2017-03-03

    Classical techniques for investigating the Rayleigh-Taylor instability include using compressed gasses 1 , rocketry 2 or linear electric motors 3 to reverse the effective direction of gravity, and accelerate the lighter fluid toward the denser fluid. Other authors e.g. 4 , 5 , 6 have separated a gravitationally unstable stratification with a barrier that is removed to initiate the flow. However, the parabolic initial interface in the case of a rotating stratification imposes significant technical difficulties experimentally. We wish to be able to spin-up the stratification into solid-body rotation and only then initiate the flow in order to investigate the effects of rotation upon the Rayleigh-Taylor instability. The approach we have adopted here is to use the magnetic field of a superconducting magnet to manipulate the effective weight of the two liquids to initiate the flow. We create a gravitationally stable two-layer stratification using standard flotation techniques. The upper layer is less dense than the lower layer and so the system is Rayleigh-Taylor stable. This stratification is then spun-up until both layers are in solid-body rotation and a parabolic interface is observed. These experiments use fluids with low magnetic susceptibility, |χ| ~ 10 -6 - 10 -5 , compared to a ferrofluids. The dominant effect of the magnetic field applies a body-force to each layer changing the effective weight. The upper layer is weakly paramagnetic while the lower layer is weakly diamagnetic. When the magnetic field is applied, the lower layer is repelled from the magnet while the upper layer is attracted towards the magnet. A Rayleigh-Taylor instability is achieved with application of a high gradient magnetic field. We further observed that increasing the dynamic viscosity of the fluid in each layer, increases the length-scale of the instability.

  17. Microbial Energetics Beneath the Taylor Glacier, Antarctica

    NASA Astrophysics Data System (ADS)

    Mikucki, J. A.; Turchyn, A. V.; Farquhar, J.; Priscu, J. C.; Schrag, D. P.; Pearson, A.

    2007-12-01

    Subglacial microbiology is controlled by glacier hydrology, bedrock lithology, and the preglacial ecosystem. These factors can all affect metabolic function by influencing electron acceptor and donor availability in the subglacial setting leaving biogeochemical signatures that can be used to determine ecosystem processes. Blood Falls, an iron-rich, episodic subglacial outflow from the Taylor Glacier in the McMurdo Dry Valleys Antarctica provides an example of how microbial community structure and function can provide insight into subglacial hydrology. This subglacial outflow contains cryoconcentrated, Pliocene-age seawater salts that pooled in the upper Taylor Valley and was subsequently covered by the advance of the Taylor Glacier. Biogeochemical measurements, culture-based techniques, and genomic analysis were used to characterize microbes and chemistry associated with the subglacial outflow. The isotopic composition of important geochemical substrates (i.e., δ34Ssulfate, Δ33Ssulfate, δ18Osulfate, δ18Owater, Δ14SDIC) were also measured to provide more detail on subglacial microbial energetics. Typically, subglacial systems, when driven to anoxia by the hydrolysis of organic matter, will follow a continuum of redox chemistries utilizing electron acceptors with decreasing reduction potential (e.g., Fe (III), sulfate, CO2). Our data provide no evidence for sulfate reduction below the Taylor Glacier despite high dissolved organic carbon (450 μM C) and measurable metabolic activity. We contend that, in the case of the Taylor Glacier, the in situ bioenergetic reduction potential has been 'short-circuited' at Fe(III)-reduction and excludes sulfate reduction and methanogenesis. Given the length of time that this marine system has been isolated from phototrophic production (~2 Mya) the ability to degrade and consume increasingly recalcitrant organic carbon is likely an important component to the observed redox chemistry. Our work indicates that glacier hydrology

  18. Insights Into the Workings of Rhyolitic Explosive Eruptions and Their Magmatic Sources

    NASA Astrophysics Data System (ADS)

    Wilson, C. J.

    2011-12-01

    The nature, role and significance of rhyolitic volcanism and its associated crustal magmatism have been widely recognised and documented over the past ~50 years. The products of such volcanism include the largest Quaternary eruptions on Earth, and these 'supereruptions' represent the largest terrestrial long-term hazard to humanity as well as reflecting resource-rich magmatic systems. Only three rhyolitic eruptions of any size have occurred over the last 100 years (Novarupta, Tuluman, Chaiten) and so patterns of rhyolitic volcanism have been inferred almost entirely from the products of past events. Numerous models for the dynamics of explosive activity have been generated from the resulting deposits, but many questions remain about the eruptions and their parental magma bodies. Central to understanding how rhyolitic systems operate is two suites of questions. First, what are the timescales of large explosive eruptions? Are they short-lived catastrophic events ('hours or days') or can they be prolonged over years to decades? How and why do large eruptions stop and start? Prehistoric large eruptions seem to show a great variety of timings, varying from days (e.g. Bishop Tuff) through months (e.g. Oruanui) to a decade or more (e.g. Huckleberry Ridge Tuff), with periods of high output alternating with hiatuses of minutes to years. Eruption rates, where they can be assessed, do not necessarily scale with the volume of the deposit. Large eruptions may be internally modulated by external (tectonic) forces, implying that eruption styles and products may be influenced by something that leaves no geological presence. Tectonic processes may control whether the evacuation of more than one magma body occurs, or trigger pairings of independent eruptions. The second suite of questions centres on the time periods over which the bodies of erupted magma accumulate and how they are assembled. Do tens to hundreds to thousands of cubic kilometres of eruptible magma collect over a time

  19. On Using Taylor's Hypothesis for Three-Dimensional Mixing Layers

    NASA Technical Reports Server (NTRS)

    LeBoeuf, Richard L.; Mehta, Rabindra D.

    1995-01-01

    In the present study, errors in using Taylor's hypothesis to transform measurements obtained in a temporal (or phase) frame onto a spatial one were evaluated. For the first time, phase-averaged ('real') spanwise and streamwise vorticity data measured on a three-dimensional grid were compared directly to those obtained using Taylor's hypothesis. The results show that even the qualitative features of the spanwise and streamwise vorticity distributions given by the two techniques can be very different. This is particularly true in the region of the spanwise roller pairing. The phase-averaged spanwise and streamwise peak vorticity levels given by Taylor's hypothesis are typically lower (by up to 40%) compared to the real measurements.

  20. Origin of a rhyolite that intruded a geothermal well while drilling at the Krafla volcano, Iceland

    USGS Publications Warehouse

    Elders, W.A.; Fridleifsson, G.O.; Zierenberg, R.A.; Pope, E.C.; Mortensen, A.K.; Gudmundsson, A.; Lowenstern, J. B.; Marks, N.E.; Owens, L.; Bird, D.K.; Reed, M.; Olsen, N.J.; Schiffman, P.

    2011-01-01

    Magma flowed into an exploratory geothermal well at 2.1 km depth being drilled in the Krafla central volcano in Iceland, creating a unique opportunity to study rhyolite magma in situ in a basaltic environment. The quenched magma is a partly vesicular, sparsely phyric, glass containing ~1.8% of dissolved volatiles. Based on calculated H2O-CO2 saturation pressures, it degassed at a pressure intermediate between hydrostatic and lithostatic, and geothermometry indicates that the crystals in the melt formed at ~900 ??C. The glass shows no signs of hydrothermal alteration, but its hydrogen and oxygen isotopic ratios are much lower than those of typical mantle-derived magmas, indicating that this rhyolite originated by anhydrous mantle-derived magma assimilating partially melted hydrothermally altered basalts. ?? 2011 Geological Society of America.

  1. 78 FR 12307 - Taylor, G. Tom; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ID-5705-001] Taylor, G. Tom; Notice of Filing Take notice that on February 14, 2013, G. Tom Taylor filed an application to hold interlocking positions pursuant to section 305(b) of the Federal Power Act, 16 U.S.C. 825d(b), Part 45 of the...

  2. Volcanic rocks of the McDermitt Caldera, Nevada-Oregon

    USGS Publications Warehouse

    Greene, Robert C.

    1976-01-01

    The McDermitt caldera, a major Miocene eruptive center is locatedin the northernmost Great Basin directly west of McDermitt, Nev. The alkali rhyolite of Jordan Meadow was erupted from the caldera and covered an area of about 60,000 sq km; the volume of rhyolite is about 960 cubic km. Paleozoic and Mesozoic sedimentary rocks and Mesozoic granodiorite form the pre-Tertiary Basement in this area.. Overlying these is a series of volcanic rocks, probably all of Miocene age. The lowest is a dacite welded tuff, a reddish-brown rock featuring abundant phenocrysts of plagioclase, hornblende, and biotite; next is a heterogeneous unit consisting of mocks ranging from basalt to dacite. Overlying these is the basalt and andesite of Orevada View, over 700 m thick and consisting of a basal unit of cinder agglutinate overlain by basalt and andesite, much of which contains conspicuous large plagioclase phenocrysts. Near Disaster Peak and Orevada View, the basalt and andesite are overlain by additional units of silicic volcanic rocks. The lower alkali rhyolite welded tuff contains abundant phenocrysts of alkali feldspar and has a vitric phase with obvious pumice and shard texture. The rhyolite of Little Peak consists of a wide variety of banded flows or welded ruffs and breccias, mostly containing abundant alkali feldspar phenocrysts. It extends south from Disaster Peak and apparently underlies the alkali rhyolite of Jordan Meadow. The quartz latite of Sage Creek lies north of Disaster Peak and consists mostly of finely mottled quartz latite with sparse minute plagioclase phenocrysts. Volcanic rock units in the east part of the area near the Cordero mine include trachyandesite, quartz labile of McConnell Canyon, and rhyolite of McCormick Ranch. The trachyandesite is dark gray and contains less than 1 percent microphenocrysts plagioclase. It is the lowest unit exposed and may correlate with part of the basalt and andesite of Orevada View. The quartz latite of McConnell Canyon is

  3. Long-lived melting of ancient lower crust of the North China Craton in response to paleo-Pacific plate subduction, recorded by adakitic rhyolite

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Song, Shuguang; Niu, Yaoling; Allen, Mark B.; Su, Li; Wei, Chunjing; Zhang, Guibin; Fu, Bin

    2017-11-01

    Magmatism in eastern China in response to paleo-Pacific plate subduction during the Mesozoic was complex, and it is unclear how and when exactly the magmas formed via thinning and partial destruction of the continental lithosphere. To better understand this magmatism, we report the results of a geochronological and geochemical study of Early Cretaceous adakitic rhyolite (erupted at 125.4 ± 2.2 Ma) in the Xintaimen area within the eastern North China Craton (NCC). In situ zircon U-Pb dating shows that this adakitic rhyolite records a long ( 70 Myrs) and complicated period of magmatism with concordant 206Pb/238U ages from 193 Ma to 117 Ma. The enriched bulk rock Sr-Nd isotopic compositions of the Xintaimen adakitic rhyolite, as well as the enriched zircon Hf and O isotopic compositions, indicate that the magmas parental to the adakitic rhyolite were derived from partial melting of the Paleoproterozoic mafic lower crust, heated by mafic melts derived from the mantle during the paleo-Pacific plate subduction. A minor older basement component is indicated by the presence of captured Neoarchean to Early Paleoproterozoic zircons. The Mesozoic zircons have restricted Hf and O isotopic compositions irrespective of their ages, suggesting that they formed from similar sources at similar melting conditions. The Xintaimen adakitic rhyolite offers an independent line of evidence that the ancient lower crust of eastern China underwent a long period ( 70 Myrs) of destruction, melting or remelting, from 193 to 120 Ma, related to the subduction of the paleo-Pacific plate beneath eastern China.

  4. The permeability evolution of tuffisites and outgassing from dense rhyolitic magma

    NASA Astrophysics Data System (ADS)

    Heap, M. J.; Tuffen, H.; Wadsworth, F. B.; Reuschlé, T.; Castro, J. M.; Schipper, C. I.

    2017-12-01

    Recent observations of rhyolitic lava effusion from eruptions in Chile indicate that simultaneous pyroclastic venting facilitates outgassing. Venting from conduit-plugging lava domes is pulsatory and occurs through shallow fracture networks that deliver pyroclastic debris and exsolved gases to the surface. However, these fractures become blocked as the particulate fracture infill sinters viscously, thus drastically reducing permeability. Tuffisites, fossilized debris-filled fractures of this venting process, are abundant in pyroclastic material ejected during hybrid explosive-effusive activity. Dense tuffisite-hosting obsidian bombs ejected from Volcán Chaitén (Chile) in 2008 afford an opportunity to better understand the permeability evolution of tuffisites within low-permeability conduit plugs, wherein gas mobility is reliant upon fracture pathways. We use laboratory measurements of the permeability and porosity of tuffisites that preserve different degrees of sintering, combined with a grainsize-based sintering model and constraints on pressure-time paths from H2O diffusion, to place first-order constraints on tuffisite permeability evolution. Inferred timescales of sintering-driven tuffisite compaction and permeability loss, spanning minutes to hours, coincide with observed vent pulsations during hybrid rhyolitic activity and, more broadly, timescales of pressurization accompanying silicic lava dome extrusion. We therefore conclude that sintering exerts a first-order control on fracture-assisted outgassing from low-permeability, conduit-plugging silicic magma.

  5. Baker & Taylor's George Coe

    ERIC Educational Resources Information Center

    Fialkoff, Francine

    2009-01-01

    In his 30 years as a library wholesaler, first as VP and general manager of Brodart Books, Library, and School Automation divisions and since 2000 as president of the Library & Education division of Baker & Taylor (B&T), George Coe has been instrumental in a whole host of innovations. They go way beyond the selection, processing, and delivery of…

  6. 75 FR 5631 - Wolf Creek Nuclear Operating Corporation, Wolf Creek Generating Station; Environmental Assessment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-03

    ... NUCLEAR REGULATORY COMMISSION [Docket No. 50-482; NRC-2010-0032] Wolf Creek Nuclear Operating Corporation, Wolf Creek Generating Station; Environmental Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory Commission (NRC) is considering issuance of an exemption, pursuant to Title...

  7. Origin of hydrous alkali feldspar-silica intergrowth in spherulites from intra-plate A2-type rhyolites at the Jabal Shama, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Surour, Adel A.; El-Nisr, Said A.; Bakhsh, Rami A.

    2016-03-01

    Miocene rhyolites (19.2 ± 0.9 Ma) at the Jabal Shama in western Saudi Arabia represent an example of rift-related silicic volcanism that took place during the formation of the Red Sea. They mostly consist of tuffaceous varieties with distinct flow banding, and pea-sized spherulites, obsidian and perlitized rhyolite tuffs. Although they have the geochemical signature of A2-type rhyolites, these silicic rocks are not typically alkaline but alkali-calcic to calc-alkaline. They developed in a within-plate regime and possibly derived from a recycled mafic subducted slab in depleted sub-continental mantle beneath the western Arabian plate. The Jabal Shama rhyolites are younger in age than their Miocene counterparts in Yemen and Ethiopia. The Jabal Shama spherulites consist of hydrous alkali feldspar-silica radial intergrowths with an occasional brown glass nucleus. Carbonate- and glass-free spherulites give up to 4.45 wt% L.O.I. The hydrous nature of these silicates and the absence of magnetite in the spherulites is a strong indication of oxidizing conditions. The spherulites contain hydrous feldspars with up to ∼6 wt% H2O, and they develop by diffusion and devitrification of glass in the rhyolite tuff at ∼800 °C. Owing to higher undercooling due to supersaturation, the radial hydrous phases within spherulites might grow faster and led to coagulation. The polygonal contacts between spherulites and the ∼120° dihedral angle suggest solid-state modification and recrystallization as the process of devitrification proceeds as low as ∼300 °C. The sum of FeO + MgO is positively correlated with total alkalies along with magnetite oxidation in the matrix to Fe-oxyhydroxides, and to the incorporation of OH- into silicates within the spehrulites themselves. Structural H2O in glass of the Jabal Shama perlite (obsidian) is considerable (∼9-12 wt%) with 3.72-5.6 wt% L.O.I. of the whole-rock. The presence of deleterious silica impurities would lower the ore grade due to

  8. Sedimentation in Hot Creek in vicinity of Hot Creek Fish Hatchery, Mono County, California

    USGS Publications Warehouse

    Burkham, D.E.

    1978-01-01

    An accumulation of fine-grained sediment in Hot Creek downstream from Hot Creek Fish Hatchery, Mono County, Calif., created concern that the site may be deteriorating as a habitat for trout. The accumulation is a phenomenon that probably occurs naturally in the problem reach. Fluctuation in the weather probably is the basic cause of the deposition of fine-grained sediment that has occurred since about 1970. Man 's activities and the Hot Creek Fish Hatchery may have contributed to the problem; the significance of these factors, however, probably was magnified because of drought conditions in 1975-77. (Woodard-USGS)

  9. Neo-Taylorism in Educational Administration?

    ERIC Educational Resources Information Center

    Gronn, Peter C.

    1982-01-01

    Reviews eight recent observational studies of school administrators and criticizes the studies' use of "time and motion" assumptions drawn from Frederick Winslow Taylor's ideas. Outlines an alternate approach based on "thick" description of administrators' work, including their talk, as exemplified in James Boswell's biography…

  10. Lithium enrichment in intracontinental rhyolite magmas leads to Li deposits in caldera basins.

    PubMed

    Benson, Thomas R; Coble, Matthew A; Rytuba, James J; Mahood, Gail A

    2017-08-16

    The omnipresence of lithium-ion batteries in mobile electronics, and hybrid and electric vehicles necessitates discovery of new lithium resources to meet rising demand and to diversify the global lithium supply chain. Here we demonstrate that lake sediments preserved within intracontinental rhyolitic calderas formed on eruption and weathering of lithium-enriched magmas have the potential to host large lithium clay deposits. We compare lithium concentrations of magmas formed in a variety of tectonic settings using in situ trace-element measurements of quartz-hosted melt inclusions to demonstrate that moderate to extreme lithium enrichment occurs in magmas that incorporate felsic continental crust. Cenozoic calderas in western North America and in other intracontinental settings that generated such magmas are promising new targets for lithium exploration because lithium leached from the eruptive products by meteoric and hydrothermal fluids becomes concentrated in clays within caldera lake sediments to potentially economically extractable levels.Lithium is increasingly being utilized for modern technology in the form of lithium-ion batteries. Here, using in situ measurements of quartz-hosted melt inclusions, the authors demonstrate that preserved lake sediments within rhyolitic calderas have the potential to host large lithium-rich clay deposits.

  11. Rapid Calculation of Spacecraft Trajectories Using Efficient Taylor Series Integration

    NASA Technical Reports Server (NTRS)

    Scott, James R.; Martini, Michael C.

    2011-01-01

    A variable-order, variable-step Taylor series integration algorithm was implemented in NASA Glenn's SNAP (Spacecraft N-body Analysis Program) code. SNAP is a high-fidelity trajectory propagation program that can propagate the trajectory of a spacecraft about virtually any body in the solar system. The Taylor series algorithm's very high order accuracy and excellent stability properties lead to large reductions in computer time relative to the code's existing 8th order Runge-Kutta scheme. Head-to-head comparison on near-Earth, lunar, Mars, and Europa missions showed that Taylor series integration is 15.8 times faster than Runge- Kutta on average, and is more accurate. These speedups were obtained for calculations involving central body, other body, thrust, and drag forces. Similar speedups have been obtained for calculations that include J2 spherical harmonic for central body gravitation. The algorithm includes a step size selection method that directly calculates the step size and never requires a repeat step. High-order Taylor series integration algorithms have been shown to provide major reductions in computer time over conventional integration methods in numerous scientific applications. The objective here was to directly implement Taylor series integration in an existing trajectory analysis code and demonstrate that large reductions in computer time (order of magnitude) could be achieved while simultaneously maintaining high accuracy. This software greatly accelerates the calculation of spacecraft trajectories. At each time level, the spacecraft position, velocity, and mass are expanded in a high-order Taylor series whose coefficients are obtained through efficient differentiation arithmetic. This makes it possible to take very large time steps at minimal cost, resulting in large savings in computer time. The Taylor series algorithm is implemented primarily through three subroutines: (1) a driver routine that automatically introduces auxiliary variables and

  12. Taylor Impact Tests and Simulations on PBX 9501

    NASA Astrophysics Data System (ADS)

    Clements, Brad; Thompson, Darla G.; Luscher, D. J.; Deluca, Racci

    2011-06-01

    Taylor impact tests have been conducted previously on plastic bonded explosives (PBXs) to characterize the stress state of these materials as they impact smooth and flat steel anvil surfaces at speeds of ~100m/s (i.e. Christopher, et al, 11th Detonation Symposium). In 2003, C. Liu and R. Ellis (unpublished, Los Alamos National Laboratory) performed Taylor tests on PBX 9501 up to speeds of 115 m/s, capturing impact images. In the work presented here, we have extended these tests to velocities of 200 m/s using a composite-lined gun barrel and no specimen sabot. Specimen images are used to validate the thermo-mechanical constitutive model ViscoSCRAM. ViscoSCRAM has been parameterized for PBX 9501 in uniaxial stress configurations. Simulating Taylor impact experiments tests the model in situations undergoing extreme damage. In addition, experimental variations to specimen confinement and friction are introduced in an attempt to establish ignition thresholds in this velocity regime.

  13. Analytical results and sample locality maps of stream-sediment, heavy-mineral-concentrate, and rock samples from the Little Jacks Creek (ID-111-006), Big Jacks Creek (ID-111-007C), Duncan Creek (ID-111-0007B), and Upper Deep Creek (ID-111-044) Wilderness Study Areas, Owyhee County, Idaho

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Erickson, M.S.; Gent, C.A.; Bradley, L.A.

    1989-01-01

    A U.S. Geological Survey report detailing the analytical results and sample locality maps of stream-sediment, heavy-mineral-concentrate, and rock samples from the Little Jacks Creek, Big Jacks Creek, Duncan Creek, and Upper Deep Creek Wilderness Study Areas, Owyhee County, Idaho

  14. Volcanic and geochemical evolution of the Carboniferous Teplice Rhyolite, Central-European Variscides (Germany and Czech Republic)

    NASA Astrophysics Data System (ADS)

    Casas, Raymundo; Breitkreuz, Christoph; Rapprich, Vladislav; Lapp, Manuel; Schulz, Bernhard

    2017-04-01

    The Altenberg-Teplice Volcanic Complex (ATVC; 325 Ma) represents one of the earliest magmatic centers of the Late- to Post-tectonic period of the Variscan orogeny in Central Europe. The ca. 35×18 km ATVC is located in the Erzgebirge/Krušné hory (Germany/Czech Republic) and hosts two principal extrusive units: (1) an initial volcanosedimentary succession preserved in the Schönfeld-Altenberg Depression Complex (Walther et al., in press) and (2) a thick volcanic pile produced during the peak eruptive stage, known as the Teplice Rhyolite (TR). The TR represents mainly a caldera-fill sequence (Benek, 1991), whose volcanic and geochemical evolution has not been fully defined. Seven petrotypes have been mapped in the TR on the Czech side (Jiránek et al., 1987). To the north, on German territory, Lobin (1986) distinguished eight petrotypes. The TR is dominated by thick sheets of welded and non-welded crystal clast-rich (< 45 %) ignimbrites, which are intercalated with rhyolitic lava-dome complexes. The ATVC has been intruded by late high-volume granite porphyritic melts and several plutons associated, in parts, with Sn-, Li mineralization. Two important drillings expose over 600 m of TR volcanics. Samples from (1) the Mi-4 borehole (Mikulov, Czech Republic) have been geochemically evaluated and a vertical reverse chemical zoning (Zr, Rb) was identified and interpreted in terms of a continuous eruption (Breiter et al., 2001). In (2) the well 2112-87 near Schmiedeberg in Germany, ignimbrites are separated by two rhyolitic, lithophysae-bearing lava units, suggesting a multistage caldera evolution. In the South of the ATVC out- and subcrops reveal a caldera outflow facies. In Czech Republic, ignimbrites prevail with a single belt of late-stage rhyolitic lavas on the eastern margin. We present sixty new whole-rock and mineral chemical data (biotite) to define the geochemical evolution, the composition and the chemical character of the TR rocks. Currently, Nd-Sr isotopes

  15. Hydrology of the Johnson Creek Basin, Oregon

    USGS Publications Warehouse

    Lee, Karl K.; Snyder, Daniel T.

    2009-01-01

    The Johnson Creek basin is an important resource in the Portland, Oregon, metropolitan area. Johnson Creek forms a wildlife and recreational corridor through densely populated areas of the cities of Milwaukie, Portland, and Gresham, and rural and agricultural areas of Multnomah and Clackamas Counties. The basin has changed as a result of agricultural and urban development, stream channelization, and construction of roads, drains, and other features characteristic of human occupation. Flooding of Johnson Creek is a concern for the public and for water management officials. The interaction of the groundwater and surface-water systems in the Johnson Creek basin also is important. The occurrence of flooding from high groundwater discharge and from a rising water table prompted this study. As the Portland metropolitan area continues to grow, human-induced effects on streams in the Johnson Creek basin will continue. This report provides information on the groundwater and surface-water systems over a range of hydrologic conditions, as well as the interaction these of systems, and will aid in management of water resources in the area. High and low flows of Crystal Springs Creek, a tributary to Johnson Creek, were explained by streamflow and groundwater levels collected for this study, and results from previous studies. High flows of Crystal Springs Creek began in summer 1996, and did not diminish until 2000. Low streamflow of Crystal Springs Creek occurred in 2005. Flow of Crystal Springs Creek related to water-level fluctuations in a nearby well, enabling prediction of streamflow based on groundwater level. Holgate Lake is an ephemeral lake in Southeast Portland that has inundated residential areas several times since the 1940s. The water-surface elevation of the lake closely tracked the elevation of the water table in a nearby well, indicating that the occurrence of the lake is an expression of the water table. Antecedent conditions of the groundwater level and autumn

  16. 75 FR 40034 - Northeastern Tributary Reservoirs Land Management Plan, Beaver Creek, Clear Creek, Boone, Fort...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-13

    ... shoreline along these reservoirs. Existing land uses around the reservoirs include TVA project operations... TENNESSEE VALLEY AUTHORITY Northeastern Tributary Reservoirs Land Management Plan, Beaver Creek, Clear Creek, Boone, Fort Patrick Henry, South Holston, Watauga, and Wilbur Reservoirs, Tennessee and...

  17. 33 CFR 334.480 - Archers Creek, Ribbon Creek and Broad River, S.C.; U.S. Marine Corps Recruit Depot rifle and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Broad River, S.C.; U.S. Marine Corps Recruit Depot rifle and pistol ranges, Parris Island. 334.480... DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.480 Archers Creek, Ribbon Creek and Broad River... navigation: (1) At the rifle range. Archers Creek between Broad River and Beaufort River and Ribbon Creek...

  18. 33 CFR 334.480 - Archers Creek, Ribbon Creek and Broad River, S.C.; U.S. Marine Corps Recruit Depot rifle and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Broad River, S.C.; U.S. Marine Corps Recruit Depot rifle and pistol ranges, Parris Island. 334.480... DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.480 Archers Creek, Ribbon Creek and Broad River... navigation: (1) At the rifle range. Archers Creek between Broad River and Beaufort River and Ribbon Creek...

  19. Bursting the Taylor cone bubble

    NASA Astrophysics Data System (ADS)

    Pan, Zhao; Truscott, Tadd

    2014-11-01

    A soap bubble fixed on a surface and placed in an electric field will take on the shape of a cone rather than constant curvature (dome) when the electrical field is not present. The phenomenon was introduced by J. Zeleny (1917) and studied extensively by C.T. Wilson & G.I. Taylor (1925). We revisit the Taylor cone problem by studying the deformation and bursting of soap bubbles in a point charge electric field. A single bubble takes on the shape of a cone in the electric field and a high-speed camera equipped with a micro-lens is used to observe the unsteady dynamics at the tip. Rupture occurs as a very small piece of the tip is torn away from the bubble toward the point charge. Based on experiments, a theoretical model is developed that predicts when rupture should occur. This study may help in the design of foam-removal techniques in engineering and provide a better understanding of an electrified air-liquid interface.

  20. The Collins Creek and Pleasant Creek Formations: Two new upper cretaceous subsurface units in the Carolina/Georgia Coastal Plain

    USGS Publications Warehouse

    ,; Prowell, D.C.; Christopher, R.A.

    2004-01-01

    This paper formally defines two new Upper Cretaceous subsurface units in the southern Atlantic Coastal Plain of North Carolina, South Carolina and Georgia: the Collins Creek Formation and the Pleasant Creek Formation. These units are confined to the subsurface of the outer Coastal Plain, and their type sections are established in corehole CHN-820 from Charleston County, S.C. The Collins Creek Formation consists of greenish-gray lignitic sand and dark-greenish-gray sandy clay and is documented in cores from Allendale, Beaufort, Berkeley, Dorchester, Jasper and Marion Counties, South Carolina, and from Screven County, Georgia. Previously, Collins Creek strata had been incorrectly assigned to the Middendorf Formation. These sediments occupy a stratigraphic position between the Turonian/Coniacian Cape Fear Formation (?) below and the proposed upper Coniacian to middle Santonian Pleasant Creek Formation above. The Collins Creek Formation is middle and late Coniacian in age on the basis of calcareous nannofossil and palynomorph analyses. The Pleasant Creek Formation consists of olive-gray sand and dark-greenish-gray silty to sandy clay and is documented in cores from New Hanover County, North Carolina, and Berkeley, Charleston, Dorchester, Horry and Marion Counties, South Carolina. The strata of this unit previously were assigned incorrectly to the Middendorf Formation and (or) the Cape Fear Formation. These sediments occupy a stratigraphic position between the proposed Collins Creek Formation below and the Shepherd Grove Formation above. The Pleasant Creek Formation is late Coniacian and middle Santonian in age, on the basis of its calcareous nannofossil and palynomorph assemblages.

  1. 6. West elevation of Drift Creek Bridge, view looking east ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. West elevation of Drift Creek Bridge, view looking east from new alignment of Drift Creek Road - Drift Creek Bridge, Spanning Drift Creek on Drift Creek County Road, Lincoln City, Lincoln County, OR

  2. Cogenetic late Pleistocene rhyolite and cumulate diorites from Augustine Volcano revealed by SIMS 238U-230Th dating of zircon, and implications for silicic magma generation by extraction from mush

    USGS Publications Warehouse

    Coombs, Michelle L.; Vazquez, Jorge A.

    2014-01-01

    Augustine Volcano, a frequently active andesitic island stratocone, erupted a late Pleistocene rhyolite pumice fall that is temporally linked through zircon geochronology to cumulate dioritic blocks brought to the surface in Augustine's 2006 eruption. Zircon from the rhyolite yield a 238U-230Th age of ∼25 ka for their unpolished rims, and their interiors yield a bimodal age populations at ∼26 ka and a minority at ∼41 ka. Zircon from dioritic blocks, ripped from Augustine's shallow magmatic plumbing system and ejected during the 2006 eruption, have interiors defining a ∼26 ka age population that is indistinguishable from that for the rhyolite; unpolished rims on the dioritic zircon are dominantly younger (≤12 ka) indicating subsequent crystallization. Zircon from rhyolite and diorite overlap in U, Hf, Ti, and REE concentrations although diorites also contain a second population of high-U, high temperature grains. Andesites that brought dioritic blocks to the surface in 2006 contain zircon with young (≤9 ka) rims and a scattering of older ages, but few zircon that crystallized during the 26 ka interval. Both the Pleistocene-age rhyolite and the 2006 dioritic inclusions plot along a whole-rock compositional trend distinct from mid-Holocene–present andesites and dacites, and the diorites, rhyolite, and two early Holocene dacites define linear unmixing trends often oblique to the main andesite array and consistent with melt (rhyolite) extraction from a mush (dacites), leaving behind a cumulate amphibole-bearing residue (diorites). Rare zircon antecrysts up to ∼300 ka from all rock types indicate that a Quaternary center has been present longer than preserved surficial deposits.

  3. Storage of Explosive versus Effusive Rhyolite Magma at the Yellowstone Volcanic Center

    NASA Astrophysics Data System (ADS)

    Gardner, J. E.

    2007-12-01

    The Yellowstone volcanic center has erupted more than 900 km3 of rhyolitic magma in the last 600,000 years (1). Most of that magma extruded as large lava flows, with only a few known explosive eruptions. Why have explosive eruptions been so rare in the recent history of the Yellowstone volcanic system? To explore that question, we focus on the Tuff of Bluff Point (TBP), about 50 km3 of magma that explosively erupted 173 ka, forming the West Thumb caldera (1). Like most other recent eruptions of Yellowstone, TBP is high silica rhyolite, with phenocrysts of quartz, sanidine, and minor ferro-pyroxenes and Fe-Ti oxides. Fe-Ti oxide and pyroxene compositions indicate that the magma had equilibrated at an oxygen fugacity equal to the QFM buffer. Rehomogenized glass inclusions (n=7) in quartz contain 2.2-3.1 wt.% water and between 400-650 ppm CO2. Those volatile contents indicate storage pressures of 90-160 MPa. Ubiquitous pyrrhotite shows that the magma was sulfur saturated, and most likely volatile saturated. The co-existing fluid would be only 42-47% water. Cathodoluminescence (CL) images of quartz phenocrysts reveal mainly concentric growth zones, with occasional dissolution boundaries present. Ti contents in quartz generally decrease from core to rim, indicating cooling of the magma, although the relative temperature changes recorded are only 10-15°, with only minor changes across dissolution boundaries. To put our observations in perspective of the recent Yellowstone magma system, we have begun examining some of the recent rhyolitic lavas, including the Pitchstone Plateau (PP), a single homogeneous lava flow of 70 km3 that erupted 79 ka (1). CL images also reveal mainly concentric quartz growth, with few dissolution boundaries obvious. Ti contents in quartz also generally decrease from core to rim, but are uniformly lower than in those in TBP, suggesting that PP magma was colder than TBP magma. Glass inclusions (n=20) in PP are generally water poor and rarely

  4. The late cretaceous Donlin Creek gold deposit, Southwestern Alaska: Controls on epizonal ore formation

    USGS Publications Warehouse

    Goldfarb, R.J.; Ayuso, R.; Miller, M.L.; Ebert, S.W.; Marsh, E.E.; Petsel, S.A.; Miller, L.D.; Bradley, D.; Johnson, Chad; McClelland, W.

    2004-01-01

    The Donlin Creek gold deposit, southwestern Alaska, has an indicated and inferred resource of approximately 25 million ounces (Moz) Au at a cutoff grade of 1.5 g/t. The ca. 70 Ma deposit is hosted in the Late Cretaceous Kuskokwim flysch basin, which developed in the back part of the are region of an active continental margin, on previously accreted oceanic terranes and continental fragments. A hypabyssal, mainly rhyolitic to rhyodacitic, and commonly porphyritic, 8- ?? 3-km dike complex, part of a regional ca. 77 to 58 Ma magmatic arc, formed a structurally competent host for the mineralization. This deposit is subdivided into about one dozen distinct prospects, most of which consist of dense quartz ?? carbonate veinlet networks that fill north-northeast-striking extensional fractures in the northeast-trending igneous rocks. The sulfide mineral assemblage is dominated by arsenopyrite, pyrite, and, typically younger, stibnite; gold is refractory within the arsenopyrite. Sericitization, carbonatization, and suffidation were the main alteration processes. Fluid inclusion studies of the quartz that hosts the resource indicate dominantly aqueous ore fluids with also about 3 to 7 mol percent CO2 ?? CH4 and a few tenths to a few mole percent NaCl + KCl. The gold-bearing fluids were mainly homogeneously trapped at approximately 275?? to 300??C and at depths of 1 to 2 km. Some of the younger stibnite may have been deposited by late-stage aqueous fluids at lower temperature. Measured ??18O values for the gold-bearing quartz range between 11 and 25 per mil; the estimated ??18O fluid values range from 7 to 12 per mil, suggesting a mainly crustally derived fluid. A broad range of measured ??D values for hydrothermal micas, between -150 and -80 per mil, is suggestive of a contribution from devolatilization of organic matter and/or minor amounts of mixing with meteoric fluids. Gold-associated hydrothermal sulfide minerals are characterized by ??34S values mainly between -16 and

  5. Ecosystem engineers drive creek formation in salt marshes.

    PubMed

    Vu, Huy D; Wie Ski, Kazimierz; Pennings, Steven C

    2017-01-01

    Ecosystem engineers affect different organisms and processes in multiple ways at different spatial scales. Moreover, similar species may differ in their engineering effects for reasons that are not always clear. We examined the role of four species of burrowing crabs (Sesarma reticulatum, Eurytium limosum, Panopeus herbstii, Uca pugnax) in engineering tidal creek networks in salt marshes experiencing sea level rise. In the field, crab burrows were associated with heads of eroding creeks and the loss of plant (Spartina alterniflora) stems. S. reticulatum was closely associated with creek heads, but densities of the other crab species did not vary across marsh zones. In mesocosm experiments, S. reticulatum excavated the most soil and strongly reduced S. alterniflora biomass. The other three species excavated less and did not affect S. alterniflora. Creek heads with vegetation removed to simulate crab herbivory grew significantly faster than controls. Percolation rates of water into marsh sediments were 10 times faster at creek heads than on the marsh platform. Biomass decomposed two times faster at creek heads than on the marsh platform. Our results indicate that S. reticulatum increases creek growth by excavating sediments and by consuming plants, thereby increasing water flow and erosion at creek heads. Moreover, it is possible that S. reticulatum burrows also increase creek growth by increasing surface and subsurface erosion, and by increasing decomposition of organic matter at creek heads. Our results show that the interaction between crab and plant ecosystem engineers can have both positive and negative effects. At a small scale, in contrast to other marsh crabs, S. reticulatum harms rather than benefits plants, and increases erosion rather than marsh growth. At a large scale, however, S. reticulatum facilitates the drainage efficiency of the marsh through the expansion of tidal creek networks, and promotes marsh health. © 2016 by the Ecological Society

  6. Reconnaissance and deep-drill site selection on Taylor Dome, Antarctica

    NASA Technical Reports Server (NTRS)

    Grootes, Pieter M.; Waddington, Edwin D.

    1993-01-01

    Taylor Dome is a small ice dome near the head of Taylor Valley, Southern Victoria Land. The location of the dome, just west of the Transantarctic Mountains, is expected to make the composition of the accumulating snow sensitive to changes in the extent of the Ross Ice Shelf. Thus, it is linked to the discharge of the West Antarctic Ice Sheet but protected against direct influences of glacial-interglacial sea-level rise. The record of past climatic and environmental changes in the ice provides a valuable complement to the radiocarbon-dated proxy record of climate derived from perched deltas, strandlines, and moraines that have been obtained in the nearby Dry Valleys. We carried out a reconnaissance of the Taylor Dome area over the past two field seasons to determine the most favorable location to obtain a deep core to bedrock. A stake network has been established with an 80-km line roughly along the crest of Taylor Dome, and 40-km lines parallel to it and offset by 10 km. These lines have been surveyed 1990/91, and the positions of 9 grid points have been determined with geoceivers. A higher density stake network was placed and surveyed around the most likely drill area in the second year. Ground-based radar soundings in both years provided details on bedrock topography and internal layering of the ice in the drill area. An airborne radar survey in January 1992, completed the radar coverage of the Taylor Dome field area.

  7. S-type rhyolites from the Tolmie Igneous Complex, Australia: deep crust origins and shallow crustal evolution

    NASA Astrophysics Data System (ADS)

    Clemens, J. D.; Birch, W. D.

    2010-05-01

    The Late Devonian Tolmie Igneous Complex, in Central Victoria, Australia, is composed mainly of Ba-rich (up to 3000 ppm) S-type rhyolite ignimbrites with SiO2 varying from 69 to 79 wt% and low Mg#s (1 to 43). Two main ignimbrite flows fill the Wabonga Caldera, the Ryans Creek and the overlying Toombullup Ignimbrites, totalling 750 to 1000 km3 in volume. The tectonic environment is late post-tectonic continental extension, with rifting and normal faulting. However, the volcanism was unimodal, without associated mafic lavas or pyroclastic rocks. Devonian red-beds underlie the Complex, Carboniferous, red-bed basins overlie the volcanic rocks, and some mafic lavas are present in the overlying red-bed sequences. The presence of almandine-rich garnet phenocrysts with rutile, in the Ryans Creek, implies minimum pressures of magma generation of 0.9 - 1.0 GPa. The Toombullup Ignimbrite contains two generations of garnet phenocrysts and three of orthopyroxene. Grt+Opx assemblages in the Toombullup imply early magmatic temperatures near 1000 ° C. The early phenocryst assemblage of Grt+Opx+Pl+Qtz constrains early magmatic crystallisation to around 0.4 GPa. Later Grt+Opx+Crd+Pl+Bt+Qtz assemblages suggest crystallisation at around 0.3 GPa and 750 to 800 ° C. The presence of ferroan Opx+Fa as late microphenocrysts suggest continued crystallisation at around 0.15 GPa and 800 ° C. Thus the magmas may were generated by high-T contact anatectic partial melting of Ba-enriched quartzofeldspathic metasediments near the base of the continental crust, during extension and mantle upwelling. There is then a record of partial crystallisation during ascent to shallow crustal pressures, where the felsic magmas evolved and interacted prior to eruption. Geochemical variations in the Complex suggest that there are at least 3 separate magma groups. Mafic-felsic magma mixing and restite unmixing can be ruled out as processes responsible for the variation. The chemistry of the magmas is

  8. Simulation of Water Quality in the Tull Creek and West Neck Creek Watersheds, Currituck Sound Basin, North Carolina and Virginia

    USGS Publications Warehouse

    Garcia, Ana Maria

    2009-01-01

    A study of the Currituck Sound was initiated in 2005 to evaluate the water chemistry of the Sound and assess the effectiveness of management strategies. As part of this study, the Soil and Water Assessment Tool (SWAT) model was used to simulate current sediment and nutrient loadings for two distinct watersheds in the Currituck Sound basin and to determine the consequences of different water-quality management scenarios. The watersheds studied were (1) Tull Creek watershed, which has extensive row-crop cultivation and artificial drainage, and (2) West Neck Creek watershed, which drains urban areas in and around Virginia Beach, Virginia. The model simulated monthly streamflows with Nash-Sutcliffe model efficiency coefficients of 0.83 and 0.76 for Tull Creek and West Neck Creek, respectively. The daily sediment concentration coefficient of determination was 0.19 for Tull Creek and 0.36 for West Neck Creek. The coefficient of determination for total nitrogen was 0.26 for both watersheds and for dissolved phosphorus was 0.4 for Tull Creek and 0.03 for West Neck Creek. The model was used to estimate current (2006-2007) sediment and nutrient yields for the two watersheds. Total suspended-solids yield was 56 percent lower in the urban watershed than in the agricultural watershed. Total nitrogen export was 45 percent lower, and total phosphorus was 43 percent lower in the urban watershed than in the agricultural watershed. A management scenario with filter strips bordering the main channels was simulated for Tull Creek. The Soil and Water Assessment Tool model estimated a total suspended-solids yield reduction of 54 percent and total nitrogen and total phosphorus reductions of 21 percent and 29 percent, respectively, for the Tull Creek watershed.

  9. Fluctuation scaling, Taylor's law, and crime.

    PubMed

    Hanley, Quentin S; Khatun, Suniya; Yosef, Amal; Dyer, Rachel-May

    2014-01-01

    Fluctuation scaling relationships have been observed in a wide range of processes ranging from internet router traffic to measles cases. Taylor's law is one such scaling relationship and has been widely applied in ecology to understand communities including trees, birds, human populations, and insects. We show that monthly crime reports in the UK show complex fluctuation scaling which can be approximated by Taylor's law relationships corresponding to local policing neighborhoods and larger regional and countrywide scales. Regression models applied to local scale data from Derbyshire and Nottinghamshire found that different categories of crime exhibited different scaling exponents with no significant difference between the two regions. On this scale, violence reports were close to a Poisson distribution (α = 1.057 ± 0.026) while burglary exhibited a greater exponent (α = 1.292 ± 0.029) indicative of temporal clustering. These two regions exhibited significantly different pre-exponential factors for the categories of anti-social behavior and burglary indicating that local variations in crime reports can be assessed using fluctuation scaling methods. At regional and countrywide scales, all categories exhibited scaling behavior indicative of temporal clustering evidenced by Taylor's law exponents from 1.43 ± 0.12 (Drugs) to 2.094 ± 0081 (Other Crimes). Investigating crime behavior via fluctuation scaling gives insight beyond that of raw numbers and is unique in reporting on all processes contributing to the observed variance and is either robust to or exhibits signs of many types of data manipulation.

  10. 33 CFR 110.72 - Blackhole Creek, Md.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... tip of an unnamed island located 0.16 mile upstream from the mouth of the creek approximately 660 feet to the west shore of the creek; northwest of a line ranging from the southwesterly tip of the island... line 100 feet from and parallel to the shore of the creek to its intersection with the south property...

  11. 33 CFR 110.72 - Blackhole Creek, Md.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... tip of an unnamed island located 0.16 mile upstream from the mouth of the creek approximately 660 feet to the west shore of the creek; northwest of a line ranging from the southwesterly tip of the island... line 100 feet from and parallel to the shore of the creek to its intersection with the south property...

  12. 33 CFR 110.72 - Blackhole Creek, Md.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... tip of an unnamed island located 0.16 mile upstream from the mouth of the creek approximately 660 feet to the west shore of the creek; northwest of a line ranging from the southwesterly tip of the island... line 100 feet from and parallel to the shore of the creek to its intersection with the south property...

  13. Microsatellite analyses of San Franciscuito Creek rainbow trout

    USGS Publications Warehouse

    Nielsen, Jennifer L.

    2000-01-01

    Microsatellite genetic diversity found in San Francisquito Creek rainbow trout support a close genetic relationship with rainbow trout (Oncorhynchus mykiss) from another tributary of San Francisco Bay, Alameda Creek, and coastal trout found in Lagunitas Creek, Marin County, California. Fish collected for this study from San Francisquito Creek showed a closer genetic relationship to fish from the north-central California steelhead ESU than for any other listed group of O. mykiss. No significant genotypic or allelic frequency associations could be drawn between San Francisquito Creek trout and fish collected from the four primary rainbow trout hatchery strains in use in California, i.e. Whitney, Mount Shasta, Coleman, and Hot Creek hatchery fish. Indeed, genetic distance analyses (δµ2) supported separation between San Francisquito Creek trout and all hatchery trout with 68% bootstrap values in 1000 replicate neighbor-joining trees. Not surprisingly, California hatchery rainbow trout showed their closest evolutionary relationships with contemporary stocks derived from the Sacramento River. Wild collections of rainbow trout from the Sacramento-San Joaquin basin in the Central Valley were also clearly separable from San Francisquito Creek fish supporting separate, independent ESUs for two groups of O. mykiss (one coastal and one Central Valley) with potentially overlapping life histories in San Francisco Bay. These data support the implementation of management and conservation programs for rainbow trout in the San Francisquito Creek drainage as part of the central California coastal steelhead ESU.

  14. The timing of compositionally-zoned magma reservoirs and mafic 'priming' weeks before the 1912 Novarupta-Katmai rhyolite eruption

    USGS Publications Warehouse

    Singer, Brad S.; Costa, Fidel; Herrin, Jason S.; Hildreth, Wes; Fierstein, Judith

    2016-01-01

    The June 6, 1912 eruption of more than 13 km3 of dense rock equivalent (DRE) magma at Novarupta vent, Alaska was the largest of the 20th century. It ejected >7 km3 of rhyolite, ~1.3 km3 of andesite and ~4.6 km3 of dacite. Early ideas about the origin of pyroclastic flows and magmatic differentiation (e.g., compositional zonation of reservoirs) were shaped by this eruption. Despite being well studied, the timing of events that led to the chemically and mineralogically zoned magma reservoir remain poorly known. Here we provide new insights using the textures and chemical compositions of plagioclase and orthopyroxene crystals and by reevaluating previous U-Th isotope data. Compositional zoning of the magma reservoir likely developed a few thousand years before the eruption by several additions of mafic magma below an extant silicic reservoir. Melt compositions calculated from Sr contents in plagioclase fill the compositional gap between 68 and 76% SiO2 in whole pumice clasts, consistent with uninterrupted crystal growth from a continuum of liquids. Thus, our findings support a general model in which large volumes of crystal-poor rhyolite are related to intermediate magmas through gradual separation of melt from crystal-rich mush. The rhyolite is incubated by, but not mixed with, episodic recharge pulses of mafic magma that interact thermochemically with the mush and intermediate magmas. Hot, Mg-, Ca-, and Al-rich mafic magma intruded into, and mixed with, deeper parts of the reservoir (andesite and dacite) multiple times. Modeling the relaxation of the Fe-Mg concentrations in orthopyroxene and Mg in plagioclase rims indicates that the final recharge event occurred just weeks prior to the eruption. Rapid addition of mass, volatiles, and heat from the recharge magma, perhaps aided by partial melting of cumulate mush below the andesite and dacite, pressurized the reservoir and likely propelled a ~10 km lateral dike that allowed the overlying rhyolite to reach the surface.

  15. Subaqueous rhyolite block lavas in the Miocene Ushikiri Formation, Shimane Peninsula, SW Japan

    NASA Astrophysics Data System (ADS)

    Kano, Kazuhiko; Takeuchi, Keiji; Yamamoto, Takahiro; Hoshizumi, Hideo

    1991-06-01

    A rhyolite mass of the Miocene Ushikiri Formation in the western part of the Shimane Peninsula, SW Japan, is a small subaqueous edifice about 600 m high and 4 km wide, formed at water depths between 200 and 1000 m. It consists mainly of three relatively flat, lava-flow units 50-300 m in maximum thickness, each of which includes lobes and their polyhedral fragments. The lava lobes are poorly to well vesiculated, glassy to microcrystalline and flow-banded and -folded. Compared with mafic pillows, they are large, having thick, quenched and brecciated, glassy crusts because of their high viscosity, surface tension and thermal conductivity. Their surfaces disintegrate into polyhedral fragments and grade into massive volcanic breccia. The massive volcanic breccia composed of the lobe fragments is poorly sorted and covered with stratified volcanic breccia of the same rock type. The rhyolite lavas commonly bifurcate in a manner similar to mafic pillow lavas. However, they are highly silicic with 1-5 vol.% phenocrysts and have elongated vesicles and flow-folds, implying that they were visco-plastic during flowage. Their surface features are similar to those of subaerial block lava. With respect to rheological and morphological features, they are subaqueous equivalents of block lava.

  16. Exceptional mobility of an advancing rhyolitic obsidian flow at Cordón Caulle volcano in Chile.

    PubMed

    Tuffen, Hugh; James, Mike R; Castro, Jonathan M; Schipper, C Ian

    2013-01-01

    The emplacement mechanisms of rhyolitic lava flows are enigmatic and, despite high lava viscosities and low inferred effusion rates, can result in remarkably, laterally extensive (>30 km) flow fields. Here we present the first observations of an active, extensive rhyolitic lava flow field from the 2011-2012 eruption at Cordón Caulle, Chile. We combine high-resolution four-dimensional flow front models, created using automated photo reconstruction techniques, with sequential satellite imagery. Late-stage evolution greatly extended the compound lava flow field, with localized extrusion from stalled, ~35 m-thick flow margins creating >80 breakout lobes. In January 2013, flow front advance continued ~3.6 km from the vent, despite detectable lava supply ceasing 6-8 months earlier. This illustrates how efficient thermal insulation by the lava carapace promotes prolonged within-flow horizontal lava transport, boosting the extent of the flow. The unexpected similarities with compound basaltic lava flow fields point towards a unifying model of lava emplacement.

  17. Coyote Creek Trash Reduction Project: Clean Creeks, Healthy Communities

    EPA Pesticide Factsheets

    Information about the SFBWQP Coyote Creek Trash Reduction Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  18. Bistability and chaos in the Taylor-Green dynamo.

    PubMed

    Yadav, Rakesh K; Verma, Mahendra K; Wahi, Pankaj

    2012-03-01

    Using direct numerical simulations, we study dynamo action under Taylor-Green forcing for a magnetic Prandtl number of 0.5. We observe bistability with weak- and strong-magnetic-field branches. Both the dynamo branches undergo subcritical dynamo transition. We also observe a host of dynamo states including constant, periodic, quasiperiodic, and chaotic magnetic fields. One of the chaotic states originates through a quasiperiodic route with phase locking, while the other chaotic attractor appears to follow the Newhouse-Ruelle-Takens route to chaos. We also observe intermittent transitions between quasiperiodic and chaotic states for a given Taylor-Green forcing.

  19. Vesiculation of rhyolite magma in the IDDP-1 borehole at Krafla, Iceland

    NASA Astrophysics Data System (ADS)

    Trewick, Laura; Tuffen, Hugh; Owen, Jacqueline; Kennedy, Ben; Eichelberger, John; Zierenberg, Robert

    2016-04-01

    In 2009 the IDDP-1 borehole at Krafla, Iceland unexpectedly intersected rhyolitic magma at 2.1 km depth [1,2], providing unprecedented opportunities to investigate silicic melt formation and storage, and potential for powerful geothermal energy production. A key objective is to constrain the nature of the rhyolitic melt and its response to drilling. As no intact core was extracted, evidence is fragmental - from glassy rhyolitic clasts retrieved from the cuttings. These exhibit a range of glass colours, vesicularities and phenocryst contents [1,2]. Here we use benchtop infra-red spectroscopy and petrological microscopy to characterise the H2O concentrations and bubble number densities within diverse glassy clasts, complemented by 1 Atm bubble growth experiments with a heated stage to investigate vesicle growth. Juvenile glassy clasts were divided into three categories (brown>banded>very dark glass). H2O concentrations within clasts showed some spatial variability, with enrichment towards bubble-rich areas that may be resorption-related but could not be adequately characterised with a benchtop source. However, mean values ranged from 1.41-1.68 wt %, with no statistically significant difference between clast types. This is broadly consistent with previous studies [1,2]. Bubble growth rates in all clast types were determined during isothermal dwells at 600, 650 and 700 °C, for which bubbles grew at 0.03-0.09, 0.11-0.31, and 0.46-0.82 μm s-1 respectively. The highest growth rates were measured for the most water-rich clast analysed - a banded clast with mean H2O of 1.68 wt %, and initially-larger bubbles also grew more rapidly. Measured bubble number densities (BNDs) range from 10[11.7] m-3 in banded clasts to 10[13.1] m-3 in very dark clasts, corresponding to decompression rates of ~0.1-1 MPa/s [3], although experimentation on IDDP-1 magma is needed to properly calibrate BNDs as a decompression rate meter. Nonetheless, such decompression rates suggest nucleation

  20. Permian A-type rhyolites of the Muráň Nappe, Inner Western Carpathians, Slovakia: in-situ zircon U-Pb SIMS ages and tectonic setting

    NASA Astrophysics Data System (ADS)

    Ondrejka, Martin; Li, Xian-Hua; Vojtko, Rastislav; Putis, Marian; Uher, Pavel; Sobocký, Tomas

    2018-04-01

    Three representative A-type rhyolitic rock samples from the Muráň Nappe of the inferred Silicic Unit of the Inner Western Carpathians (Slovakia) were dated using the high-precision SIMS U-Pb isotope technique on zircons. The geochronological data presented in this paper is the first in-situ isotopic dating of these volcanic rocks. Oscillatory zoned zircon crystals mostly revealed concordant Permian (Guadalupian) ages: 266.6 ± 2.4 Ma in Tisovec-Rejkovo (TIS-1), 263.3 ± 1.9 Ma in Telgárt-Gregová Hill (TEL-1) and 269.5 ± 1.8 Ma in Veľká Stožka-Dudlavka (SD-2) rhyolites. The results indicate that the formation of A-type rhyolites and their plutonic equivalents are connected to magmatic activity during the Permian extensional tectonics and most likely related to the Pangea supercontinent break-up.

  1. Atmospheric negative corona discharge using a Taylor cone as liquid electrode

    NASA Astrophysics Data System (ADS)

    Sekine, Ryuto; Shirai, Naoki; Uchida, Satoshi; Tochikubo, Fumiyoshi

    2012-10-01

    We examined characteristics of atmospheric negative corona discharge using liquid needle cathode. As a liquid needle cathode, we adopted Taylor cone with conical shape. A nozzle with inner diameter of 10 mm is filled with liquid, and a plate electrode is placed at 10 mm above the nozzle. By applying a dc voltage between electrodes, Taylor cone is formed. To change the liquid property, we added sodium dodecyl sulfate to reduce the surface tension, sodium sulfate to increase the conductivity, and polyvinyl alcohol to increase the viscosity, in distilled water. The liquid, with high surface tension such as pure water could not form a Taylor cone. When we reduced surface tension, a Taylor cone was formed and the stable corona discharge was observed at the tip of the cone. When we increased viscosity, a liquid filament protruded from the solution surface was formed and corona discharge was observed along the filament at position 0.7-1.0 mm above from the tip of the cone. Increasing the conductivity resulted in the higher light intensity of corona and the lower corona onset voltage. When we use the metal needle electrode, the corona discharge depends on the voltage and the gap length. Using Taylor cone, different types of discharges were observed by changing the property of the liquid.

  2. Fermilab | Tritium at Fermilab | Ferry Creek Results

    Science.gov Websites

    newsletter Ferry Creek Results chart This chart (click chart for larger version) shows the levels of tritium following the detection of low levels of tritium in Indian Creek in November 2005. The levels of tritium in . Fermilab continues to monitor the ponds and creeks on its site and take steps to keep the levels of tritium

  3. Summer food habits and trophic overlap of roundtail chub and creek chub in Muddy Creek, Wyoming

    USGS Publications Warehouse

    Quist, M.C.; Bower, M.R.; Hubert, W.A.

    2006-01-01

    Native fishes of the Upper Colorado River Basin have experienced substantial declines in abundance and distribution, and are extirpated from most of Wyoming. Muddy Creek, in south-central Wyoming (Little Snake River watershed), contains sympatric populations of native roundtail chub (Gila robusta), bluehead sucker, (Catostomus discobolus), and flannelmouth sucker (C. tatipinnis), and represents an area of high conservation concern because it is the only area known to have sympatric populations of all 3 species in Wyoming. However, introduced creek chub (Semotilus atromaculatus) are abundant and might have a negative influence on native fishes. We assessed summer food habits of roundtail chub and creek chub to provide information on the ecology of each species and obtain insight on potential trophic overlap. Roundtail chub and creek chub seemed to be opportunistic generalists that consumed a diverse array of food items. Stomach contents of both species were dominated by plant material, aquatic and terrestrial insects, and Fishes, but also included gastropods and mussels. Stomach contents were similar between species, indicating high trophic, overlap. No length-related patterns in diet were observed for either species. These results suggest that creek chubs have the potential to adversely influence the roundtail chub population through competition for food and the native fish assemblage through predation.

  4. Deception Creek Experimental Forest (Idaho)

    Treesearch

    Russell T. Graham; Theresa B. Jain

    2004-01-01

    Deception Creek Experimental Forest is located in one of the most productive forests of the Rocky Mountains. When the forest was established in 1933, large, old western white pines were important for producing lumber products, matches, and toothpicks. Deception Creek is located in the heart of the western white pine forest type, allowing researchers to focus on the...

  5. Beyond linear fields: the Lie–Taylor expansion

    PubMed Central

    2017-01-01

    The work extends the linear fields’ solution of compressible nonlinear magnetohydrodynamics (MHD) to the case where the magnetic field depends on superlinear powers of position vector, usually, but not always, expressed in Cartesian components. Implications of the resulting Lie–Taylor series expansion for physical applicability of the Dolzhansky–Kirchhoff (D–K) equations are found to be positive. It is demonstrated how resistivity may be included in the D–K model. Arguments are put forward that the D–K equations may be regarded as illustrating properties of nonlinear MHD in the same sense that the Lorenz equations inform about the onset of convective turbulence. It is suggested that the Lie–Taylor series approach may lead to valuable insights into other fluid models. PMID:28265187

  6. Drilling a ';super-volcano': volcanology of the proximal rhyolitic volcanic succession in the HOTSPOT deep drill hole, Idaho, Yellowstone hot-spot track

    NASA Astrophysics Data System (ADS)

    Knott, T.; Branney, M. J.; Christiansen, E. H.; Reichow, M. K.; McCurry, M. O.; Shervais, J. W.

    2013-12-01

    Project HOTSPOT seeks to understand the bimodal volcanism in the Yellowstone-Snake River large igneous province, including the magma generation and eruption history. The 1.9 km-deep Kimberly well in southern Idaho, USA, reveals a proximal mid-Miocene rhyolitic and basaltic volcanic succession marginal to the postulated Twin Falls eruptive centre. Three rhyolitic eruption-units (each we interpret to record a single eruption, based on core descriptions) are separated by basaltic lavas, palaeosols and volcaniclastic sediments, and are being dated by 40Ar-39Ar on plagioclases. Whole-rock and mineral chemical data, from each unit, has been compiled to facilitate correlation with well-studied eruption-units at more distal outcrops, where we have detailed chemical, palaeomagnetic and radiometric characterisation. Results will contribute to frequency and volume calculations for some of the most catastrophic super-eruptions in Earth history. As the volcanism is of Snake River (SR)-type and lacks typical pumice fall deposits and low-moderate grade ignimbrites, interpreting the physical origin of the units can be difficult; many SR-type rheomorphic ignimbrites are flow-banded and resemble lavas, and the distinction between these and true lavas involves interpretation of critical evidence from lower contacts (e.g., distinguishing basal lava autobreccias from peperitic contacts, which can occur at the bases of SR-type lavas and ignimbrites). The lower most eruption-unit, ';Kimberly Rhyolite 1,' is >1323 m thick (base not seen) and suggests ponding in the margin of a caldera. Few vitroclastic textures are preserved, but a rheomorphic ignimbrite origin is inferred by folded fabrics and scattered obsidian chips (2-5 mm in size) within a thick lithoidal zone, which passes sharply upwards into a 39.6 m thick vitrophyre with an autobrecciated top and it is overlain by 18 m (caldera?) lake sediments. However, lithic mesobreccia, that characterise caldera fills elsewhere, are not seen

  7. 36 CFR 294.29 - List of designated Idaho Roadless Areas.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-Spring Creek 111 X X X X Caribou Gibson 181 X X Caribou Hell Hole 168 X X Caribou Huckleberry Basin 165 X... Mink 151 X X X Caribou Williams Creek 174 X X X Caribou Worm Creek 170 X X X Challis Blue Bunch... Creek 509 X X Salmon South Panther 504 X Salmon Taylor Mountain 902 X Salmon West Big Hole 943 X X X X...

  8. 36 CFR 294.29 - List of designated Idaho Roadless Areas.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-Spring Creek 111 X X X X Caribou Gibson 181 X X Caribou Hell Hole 168 X X Caribou Huckleberry Basin 165 X... Mink 151 X X X Caribou Williams Creek 174 X X X Caribou Worm Creek 170 X X X Challis Blue Bunch... Creek 509 X X Salmon South Panther 504 X Salmon Taylor Mountain 902 X Salmon West Big Hole 943 X X X X...

  9. 77 FR 55784 - Proposed Flood Elevation Determinations; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... the flooding sources for Franklin County, North Carolina and Incorporated Areas. The flooding source... ``Franklin County, North Carolina, and Incorporated Areas'' addressed several flooding sources, including Taylors Creek. The proposed rule incorrectly listed the flooding source name as Taylors Branch instead of...

  10. Nature and significance of Austin-Taylor unconformity on western margin of east Texas basin

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Surles, M.A. Jr.

    1984-04-01

    The Taylor Marl unconformably overlies the Austin Chalk on the western margin of the East Texas basin. Along this contact, up to 275 ft (84 m) of upper Austin is missing in the Waco area and up to 450 ft (137 m) in Bell County. However, the Austin Chalk appears to have been more-or-less uniformly deposited throughout the study area. Apparently regional uplift caused a regression that terminated Austin deposition and was related to the erosion of the upper Chalk. While the unconformity is areally extensive, slightly angular, and accounts for a relatively long period of time, the mechanism ofmore » erosion that caused the unconformity is still uncertain. Erosion was terminated by the deposition of the lower Taylor Marl. Taylor A, the lowermost subdivision of the lower Taylor, was deposited in a near-shore environment that was highly variable. Of particular interest is the relationship of this unconformity to structure and probably to oil occurrence in the Austin Chalk in McLennan and Falls Counties. Major Austin fracturing, which apparently does not extend into the Taylor in Falls County, clearly indicates that structure in the Chalk, at least in part, antedates Taylor deposition. Oil occurrence in the Chalk is clearly related to fracturing and probably is localized by post-Austin-pre-Taylor fracture systems.« less

  11. Field-based description of rhyolite lava flows of the Calico Hills Formation, Nevada National Security Site, Nevada

    USGS Publications Warehouse

    Sweetkind, Donald S.; Bova, Shiera C.

    2015-01-01

    In the area south of the Rainier Mesa caldera, surface and subsurface geologic data are combined to interpret the overall thickness of the Calico Hills Formation and the proportion of lava flow lithology across the study area. The formation is at least 500 meters (m) thick and contains the greatest proportion of rhyolite lava flow to the northeast of Yucca Mountain in the lower part of Fortymile Canyon. The formation thins to the south and southwest where it is between 50 and 200 m thick beneath Yucca Mountain and contains no rhyolite lavas. Geologic mapping and field-based correlation of individual lava flows allow for the interpretation of the thickness and extent of specific flows and the location of their source areas. The most extensive flows have widths from 2 to 3 kilometers (km) and lengths of at least 5–6 km. Lava flow thickness varies from 150 to 250 m above interpreted source vents to between 30 and 80 m in more distal locations. Rhyolite lavas have length-to-height ratios of 10:1 or greater and, in one instance, a length-to-width ratio of 2:1 or greater, implying a tongue-shaped geometry instead of circular domes or tabular bodies. Although geologic mapping did not identify any physical feature that could be positively identified as a vent, lava flow thickness and the size of clasts in subjacent pyroclastic deposits suggest that primary vent areas for at least some of the flows in the study area are on the east side of Fortymile Canyon, to the northeast of Yucca Mountain.

  12. 1. Deep Creek Road, picnic pavilion Great Smoky Mountains ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Deep Creek Road, picnic pavilion - Great Smoky Mountains National Park Roads & Bridges, Deep Creek Road, Between Park Boundary near Bryson City & Deep Creek Campground, Gatlinburg, Sevier County, TN

  13. Floods in Starkweather Creek basin, Madison, Wisconsin

    USGS Publications Warehouse

    Lawrence, Carl L.; Holmstrom, Barry K.

    1972-01-01

    The reaches evaluated are (1) Starkweather Creek and West Branch Starkweather Creek, for a distance of 6.0 river miles from the mouth at Lake Monona upstream to the U.S. Highway 51 crossing north of Truax Field; and (2) East Branch Starkweather Creek (2.8 river miles), from its confluence with the West Branch near Milwaukee Street upstream to a point near the Interstate Highway 90-94 crossing.

  14. Structural Development and Oxidation of the Takanoobane Rhyolite Lava in Aso Caldera, Japan

    NASA Astrophysics Data System (ADS)

    Furukawa, K.; Uno, K.; Miyagi, I.

    2007-12-01

    The Takanoobane rhyolite lava (hereafter described as the TR lava) is distributed in the western part of Aso caldera, middle Kyushu Island, SW Japan. The TR lava is one of the central cones. The volume, SiO2 contents and K-Ar age are 0.14km3 (Miyabuchi et al., 2004), 71-72% (Furukawa, 2006) and 51+-5ka (Matsumoto et al., 1991), respectively. The TR lava was effused in a subaerial environment. In this study, we show vertical structural variation and the development of the TR lava from the four drilling cores obtained by Aso Volcanological Laboratory in 2001-2002. The TR lava is about 90m thick in the proximal part, and the internal structures are divided into three parts: Alternation of the pumiceous layers and the obsidian layers (the upper part), the crystalline rhyolite layer (the central part), and the obsidian layer (the lower part). This structural variation apparently resembles to that of the Obsidian Dome near long valley caldera in eastern California (Manley and Fink, 1987). The central crystalline rhyolite layer of the TR lava is characterized by the development of the flow structure, which is composed of interconnected minute cavities. The shapes and sizes of the structure are varied from stubby or lens to flattened and from a few mm to above 5 cm in length, respectively. The morphology of the flow structure tends to be flattened with distance from the source region. It is probably due to shear stress caused by the lava movement We described the vertical variation of the mineral assemblage of Fe-Ti oxides. It shows that the highly oxidized Fe-Ti oxides tend to be distributed around the flow structure. Thus, the part is selectively oxidized. It is supported also by the rock magnetic experiments. Above studies and cooling history calculated by a numerical modeling show that the oxidation was caused by the increasing of fO2 at the part. We interpret that the increasing of fO2 was caused by the release of hydrogen from the degassing lava. Hydrogen should be

  15. 2. Deep Creek Road, old bridge at campground entrance. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Deep Creek Road, old bridge at campground entrance. - Great Smoky Mountains National Park Roads & Bridges, Deep Creek Road, Between Park Boundary near Bryson City & Deep Creek Campground, Gatlinburg, Sevier County, TN

  16. Origin and potential geothermal significance of China Hat and other late Pleistocene topaz rhyolite lava domes of the Blackfoot Volcanic Field, SE Idaho

    NASA Astrophysics Data System (ADS)

    McCurry, M. O.; Pearson, D. M.; Welhan, J. A.; Kobs-Nawotniak, S. E.; Fisher, M. A.

    2014-12-01

    The Snake River Plain and neighboring regions are well known for their high heat flow and robust Neogene-Quaternary tectonic and magmatic activity. Interestingly, however, there are comparatively few surficial manifestations of geothermal activity. This study is part of a renewed examination of this region as a possible hidden or blind geothermal resource. We present a testable, integrated volcanological, petrogenetic, tectonic and hydrothermal conceptual model for 57 ka China Hat and cogenetic topaz rhyolite lava domes of the Blackfoot Volcanic Field. This field is well suited for analysis as a blind resource because of its distinctive combination of (1) young bimodal volcanism, petrogenetic evidence of shallow magma storage and evolution, presence of coeval extension, voluminous travertine deposits, and C- and He-isotopic evidence of active magma degassing; (2) a paucity of hot springs or other obvious indicators of a geothermal resource in the immediate vicinity of the lava domes; and (3) proximity to a region of high crustal heat flow, high-T geothermal fluids at 2.5-5 km depth and micro-seismicity characterized by its swarming nature. Eruptions of both basalt and rhyolite commonly evolve from minor phreatomagmatic to effusive. In our model, transport of both magmatic and possible deep crustal aqueous fluids may be controlled by preexisting crustal structures, including west-dipping thrust faults. Geochemical evolution of rhyolite magma is dominated by mid- to upper-crustal fractional crystallization (with pre-eruption storage and phenocryst formation at ~14 km). Approximately 1.2 km3 of topaz rhyolite have been erupted since 1.4 Ma, yielding an average eruption rate of 0.8 km3/m.y. Given reasonable assumptions of magma cumulate formation and eruption rates, and initial and final volatile concentrations, we infer average H2O and CO2 volatile fluxes from the rhyolite source region of ~2MT/year and 340 T/day, respectively. Lithium flux may be comparable to CO2.

  17. Assessment of hydrology, water quality, and trace elements in selected placer-mined creeks in the birch creek watershed near central, Alaska, 2001-05

    USGS Publications Warehouse

    Kennedy, Ben W.; Langley, Dustin E.

    2007-01-01

    Executive Summary The U.S. Geological Survey, in cooperation with the Bureau of Land Management, completed an assessment of hydrology, water quality, and trace-element concentrations in streambed sediment of the upper Birch Creek watershed near Central, Alaska. The assessment covered one site on upper Birch Creek and paired sites, upstream and downstream from mined areas, on Frying Pan Creek and Harrison Creek. Stream-discharge and suspended-sediment concentration data collected at other selected mined and unmined sites helped characterize conditions in the upper Birch Creek watershed. The purpose of the project was to provide the Bureau of Land Management with baseline information to evaluate watershed water quality and plan reclamation efforts. Data collection began in September 2001 and ended in September 2005. There were substantial geomorphic disturbances in the stream channel and flood plain along several miles of Harrison Creek. Placer mining has physically altered the natural stream channel morphology and removed streamside vegetation. There has been little or no effort to re-contour waste rock piles. During high-flow events, the abandoned placer-mine areas on Harrison Creek will likely contribute large quantities of sediment downstream unless the mined areas are reclaimed. During 2004 and 2005, no substantial changes in nutrient or major-ion concentrations were detected in water samples collected upstream from mined areas compared with water samples collected downstream from mined areas on Frying Pan Creek and Harrison Creek that could not be attributed to natural variation. This also was true for dissolved oxygen, pH, and specific conductance-a measure of total dissolved solids. Sample sites downstream from mined areas on Harrison Creek and Frying Pan Creek had higher median suspended-sediment concentrations, by a few milligrams per liter, than respective upstream sites. However, it is difficult to attach much importance to the small downstream increase

  18. Rayleigh-Taylor instability and mushroom-pattern formation in a two-component Bose-Einstein condensate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sasaki, Kazuki; Suzuki, Naoya; Saito, Hiroki

    2009-12-15

    The Rayleigh-Taylor instability at the interface in an immiscible two-component Bose-Einstein condensate is investigated using the mean field and Bogoliubov theories. Rayleigh-Taylor fingers are found to grow from the interface and mushroom patterns are formed. Quantized vortex rings and vortex lines are then generated around the mushrooms. The Rayleigh-Taylor instability and mushroom-pattern formation can be observed in a trapped system.

  19. Surface waters of North Boggy Creek basin in the Muddy Boggy Creek basin in Oklahoma

    USGS Publications Warehouse

    Laine, L.L.

    1958-01-01

    Analysis of short-term streamflow data in North Boggy Creek basin indicates that the average runoff in this region is substantial. The streamflow is highly variable from year to year and from month to month. The estimated total yield from the North Boggy Creek watershed of 231 square miles averages 155,000 acre-feet annually, equivalent to an average runoff depth of 12 1/2 inches. Almost a fourth of the annual volume is contributed by Chickasaw Creek basin, where about 35,000 acre-feet runs off from 46 square miles. Two years of records show a variation in runoff for the calendar year 1957 in comparison to 1956 in a ratio of 13 to 1 for the station on North Boggy Creek and a ratio of 18 to 1 for the station on Chickasaw Creek. In a longer-term record downstream on Muddy Boggy Creek near Farris, the corresponding range was 17 to 1, while the calendar years 1945 and 1956 show a 20-fold variation in runoff. Within a year the higher runoff tends to occur in the spring months, April to June, a 3-month period that, on the average, accounts for at least half of the annual flow. High runoff may occur during any month in the year, but in general, the streamflow is relatively small in the summer. Records for the gaging stations noted indicate that there is little or no base flow in the summer, and thus there will be periods of no flow at times in most years. The variation in runoff during a year is suggested by a frequency analysis of low flows at the reference station on Muddy Boggy Creek near Farris. Although the mean flow at that site is 955 cfs (cubic feet per second), the median daily flow is only 59 cfs and the lowest 30-day flow in a year will average less than 1 cfs in 4 out of 10 years on the average. The estimated mean flow on North Boggy Creek near Stringtown is 124 cfs, but the estimated median daily flow is only 3 1/2 cfs. Because of the high variability in streamflow, development of storage by impoundment will be necessary to attain maximum utilization of the

  20. Water quality of the Swatara Creek Basin, PA

    USGS Publications Warehouse

    McCarren, Edward F.; Wark, J.W.; George, J.R.

    1964-01-01

    The Swatara Creek of the Susquehanna River Basin is the farthest downstream sub-basin that drains acid water (pH of 4.5 or less) from anthracite coal mines. The Swatara Creek drainage area includes 567 square miles of parts of Schuylkill, Berks, Lebanon, and Dauphin Counties in Pennsylvania.To learn what environmental factors and dissolved constituents in water were influencing the quality of Swatara Creek, a reconnaissance of the basin was begun during the summer of 1958. Most of the surface streams and the wells adjacent to the principal tributaries of the Creek were sampled for chemical analysis. Effluents from aquifers underlying the basin were chemically analyzed because ground water is the basic source of supply to surface streams in the Swatara Creek basin. When there is little runoff during droughts, ground water has a dominating influence on the quality of surface water. Field tests showed that all ground water in the basin was non-acidic. However, several streams were acidic. Sources of acidity in these streams were traced to the overflow of impounded water in unworked coal mines.Acidic mine effluents and washings from coal breakers were detected downstream in Swatara Creek as far as Harper Tavern, although the pH at Harper Tavern infrequently went below 6.0. Suspended-sediment sampling at this location showed the mean daily concentration ranged from 2 to 500 ppm. The concentration of suspended sediment is influenced by runoff and land use, and at Harper Tavern it consisted of natural sediments and coal wastes. The average daily suspended-sediment discharge there during the period May 8 to September 30, 1959, was 109 tons per day, and the computed annual suspended-sediment load, 450 tons per square mile. Only moderate treatment would be required to restore the quality of Swatara Creek at Harper Tavern for many uses. Above Ravine, however, the quality of the Creek is generally acidic and, therefore, of limited usefulness to public supplies, industries and

  1. PEOPLE IN PHYSICS: Interview with Charles Taylor

    NASA Astrophysics Data System (ADS)

    Pople, Conducted by Stephen

    1996-07-01

    Charles Taylor started his university teaching career at UMIST in 1948. In 1965 he became Professor and Head of the Department of Physics at University College, Cardiff. He was a Vice-President of the Institute of Physics from 1970 to 1975, and Professor of Experimental Physics at the Royal Institution from 1977 until 1989. Over the years, Professor Taylor has delighted audiences of all ages with his demonstration lectures, including the Royal Institution Christmas Lectures televised in 1971 and 1989. In 1986 he became the first recipient of the Royal Society's Michael Faraday Award for contributions to the public understanding of science. His many books include Exploring Music, The Art and Science of the Lecture Demonstration, and also the Oxford Children's Book of Science, co-written with interviewer Stephen Pople.

  2. Reconnaissance study of the Taylor Mountains pluton, southwestern Alaska

    USGS Publications Warehouse

    Hudson, Travis L.; Miller, Marti L.; Klimasauskas, Edward P.; Layer, Paul W.

    2010-01-01

    The Taylor Mountains pluton is a Late Cretaceous to early Tertiary (median age 65 + or ? 2 Ma) epizonal, composite biotite granite stock located about 235 km (145 mi) northeast of Dillingham in southwestern Alaska. This 30 km2 (12 mi2) pluton has sharp and discordant contacts with hornfels that developed in Upper Cretaceous clastic sedimentary rocks of the Kuskokwim Group. The three intrusive phases in the Taylor Mountains pluton, in order of emplacement, are (1) porphyritic granite containing large K-feldspar phenocrysts in a coarse-grained groundmass, (2) porphyritic granite containing large K-feldspar and smaller, but still coarse, plagioclase, quartz, and biotite phenocrysts in a fine-grained groundmass, and (3) fine-grained, leucocratic, equigranular granite. The porphyritic granites have different emplacement histories, but similar compositions; averages are 69.43 percent SiO2, 1.62 percent CaO, 5.23 percent FeO+MgO, 3.11 percent Na2O, and 4.50 percent K2O. The fine-grained, equigranular granite is distinctly felsic compared to porphyritic granite; it averages 75.3 percent SiO2, 0.49 percent CaO, 1.52 percent FeO+MgO, 3.31 percent Na2O, and 4.87 percent K2O. Many trace elements including Ni, Cr, Sc, V, Ba, Sr, Zr, Y, Nb, La, Ce, Th, and Nd are strongly depleted in fine-grained equigranular granite. Trace elements are not highly enriched in any of the granites. Known hydrothermal alteration is limited to one tourmaline-quartz replacement zone in porphyritic granite. Mineral deposits in the Taylor Mountains area are primarily placer gold (plus wolframite, cassiterite, and cinnabar); sources for these likely include scattered veins in hornfels peripheral to the Taylor Mountain pluton. The granite magmas that formed the Taylor Mountains pluton are thought to represent melted continental crust that possibly formed in response to high heat flow in the waning stage of Late Cretaceous subduction beneath interior Alaska.

  3. CEAP in the Cedar Creek watershed

    USDA-ARS?s Scientific Manuscript database

    This publication provides research updates from the Conservation Effects Assessment Project (CEAP) in the Cedar Creek watershed in Indiana. In this inaugural issue, we explain the CEAP and why the National Soil Erosion Research Lab is doing research in Cedar Creek. It also includes a 'Research Featu...

  4. 33 CFR 117.809 - Tonawanda Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Tonawanda Creek. 117.809 Section 117.809 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117.809 Tonawanda Creek. The draw of the...

  5. 33 CFR 117.555 - College Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false College Creek. 117.555 Section 117.555 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.555 College Creek. The draws of the...

  6. 33 CFR 117.231 - Brandywine Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Brandywine Creek. 117.231 Section 117.231 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Delaware § 117.231 Brandywine Creek. The draw of the...

  7. 33 CFR 117.324 - Rice Creek.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Rice Creek. 117.324 Section 117.324 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.324 Rice Creek. The CSX Railroad Swingbridge, mile...

  8. 33 CFR 117.324 - Rice Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Rice Creek. 117.324 Section 117.324 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.324 Rice Creek. The CSX Railroad Swingbridge, mile...

  9. 33 CFR 117.917 - Battery Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Battery Creek. 117.917 Section 117.917 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements South Carolina § 117.917 Battery Creek. The draw of...

  10. 33 CFR 117.917 - Battery Creek.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Battery Creek. 117.917 Section 117.917 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements South Carolina § 117.917 Battery Creek. The draw of...

  11. 33 CFR 117.917 - Battery Creek.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Battery Creek. 117.917 Section 117.917 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements South Carolina § 117.917 Battery Creek. The draw of...

  12. 33 CFR 117.917 - Battery Creek.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Battery Creek. 117.917 Section 117.917 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements South Carolina § 117.917 Battery Creek. The draw of...

  13. 33 CFR 117.917 - Battery Creek.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Battery Creek. 117.917 Section 117.917 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements South Carolina § 117.917 Battery Creek. The draw of...

  14. The effect of prior hydrothermal alteration on the melting behaviour during rhyolite formation in Yellowstone, and its importance in the generation of low-δ18O magmas

    NASA Astrophysics Data System (ADS)

    Troch, Juliana; Ellis, Ben S.; Harris, Chris; Ulmer, Peter; Bachmann, Olivier

    2018-01-01

    Constraining the contribution of crustal lithologies to silicic magmas has important implications for understanding the dynamics of these potentially highly explosive systems. Low-δ18O rhyolite lavas erupted after caldera-forming events in Yellowstone have been interpreted as the products of bulk crustal melting of previously deposited and hydrothermally altered rhyolitic material in the down-dropped caldera roof. For lack of compositional data, the "self-cannibalisation bulk melting"-theory relies on the assumption that hydrothermally altered materials are near-cotectic and hydrous (>3 wt% H2O) and will therefore readily melt at temperatures below 850 °C. In this study, we examine the drillcores Y2, Y9 and Y13 from a USGS drilling campaign in Yellowstone in order to characterise the hydrothermally altered material in terms of major and trace elements, oxygen isotopes and water contents. Rhyolite δ18O values can decrease from "normal" (+5.8 to +6.1‰) on the surface to as low as -5‰ at depths of 100-160 m and probably lower as a function of increasing temperature with depth. While material in the drillcores is variably altered and silicified, oxygen isotope exchange in these samples is not accompanied by systematic changes in major and trace element composition and is independent of uptake of water. More than 75% of the drillcore samples have <0.5 wt% H2O, making water the most limiting factor during melting. Modelled melting curves using rhyolite-MELTS suggest a maximum of 35% melt can be created at 850 °C, and that bulk melting would require extremely high temperatures >1100 °C. Therefore, large-scale bulk melting is unrealistic and low-δ18O rhyolite magmas more likely result from assimilation of <30% partially melted altered crust with low δ18O into a normal-δ18O rhyolite magma from the main reservoir. This mechanism is supported by isotopic mass-balance models as well as thermal and volumetric constraints, and may be similarly applicable to other low

  15. Walnut Creek and Squaw Creek Watersheds, Iowa: National Institute of Food and Agriculture-Conservation Effects Assessment Project

    USDA-ARS?s Scientific Manuscript database

    The Walnut Creek Watershed NIFA-CEAP Watershed project was designed to assess water quality benefits and economic costs from the adoption of a prairie ecosystem (conservation practice implementation) at a watershed scale. This chapter describes and summarizes the paired watershed (Walnut Creek and S...

  16. A cosmological Slavnov-Taylor identity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Collins, Hael; Holman, R.; Vardanyan, Tereza, E-mail: hcollins@andrew.cmu.edu, E-mail: rh4a@andrew.cmu.edu, E-mail: tvardany@andrew.cmu.edu

    We develop a method for treating the consistency relations of inflation that includes the full time-evolution of the state. This approach relies only on the symmetries of the inflationary setting, in particular a residual conformal symmetry in the spatial part of the metric, along with general properties which hold for any quantum field theory. As a result, the consistency relations that emerge, which are essentially the Slavnov-Taylor identities associated with this residual conformal symmetry, apply very generally: they are true of the full Green's functions, hold largely independently of the particular inflationary model, and can be used for arbitrary states.more » We illustrate these techniques by showing the form assumed by the standard consistency relation between the two and three-point functions for the primordial scalar fluctuations when they are in a Bunch-Davies state. But because we have included the full evolution of the state, this approach works for a general initial state as well and does not need to have assumed that inflation began in the Bunch-Davies state. We explain how the Slavnov-Taylor identity is modified for these more general states.« less

  17. Geologic map of the Skull Creek Quadrangle, Moffat County Colorado

    USGS Publications Warehouse

    Van Loenen, R. E.; Selner, Gary; Bryant, W.A.

    1999-01-01

    The Skull Creek quadrangle is in northwestern Colorado a few miles north of Rangely. The prominent structural feature of the Skull Creek quadrangle is the Skull Creek monocline. Pennsylvanian rocks are exposed along the axis of the monocline while hogbacks along its southern flank expose rocks that are from Permian to Upper Cretaceous in age. The Wolf Creek monocline and the Wolf Creek thrust fault, which dissects the monocline, are salient structural features in the northern part of the quadrangle. Little or no mineral potential exists within the quadrangle. A geologic map of the Lazy Y Point quadrangle, which is adjacent to the Skull Creek quadrangle on the west, is also available (Geologic Investigations Series I-2646). This companian map shows similar geologic features, including the western half of the Skull Creek monocline. The geology of this quadrangle was mapped because of its proximity to Dinosaur National Monument. It is adjacent to quadrangles previously mapped to display the geology of this very scenic and popular National Monument. The Skull Creek quadrangle includes parts of the Skull Creek Wilderness Study Area, which was assessed for its mineral resource potential.

  18. 33 CFR 117.401 - Trail Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Trail Creek. 117.401 Section 117.401 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Indiana § 117.401 Trail Creek. (a) The draw of the Franklin...

  19. 33 CFR 117.233 - Broad Creek.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Broad Creek. 117.233 Section 117.233 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Delaware § 117.233 Broad Creek. (a) The draw of the Conrail...

  20. 33 CFR 117.233 - Broad Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Broad Creek. 117.233 Section 117.233 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Delaware § 117.233 Broad Creek. (a) The draw of the Conrail...

  1. 33 CFR 117.233 - Broad Creek.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Broad Creek. 117.233 Section 117.233 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Delaware § 117.233 Broad Creek. (a) The draw of the Conrail...

  2. 33 CFR 117.233 - Broad Creek.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Broad Creek. 117.233 Section 117.233 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Delaware § 117.233 Broad Creek. (a) The draw of the Conrail...

  3. 33 CFR 117.233 - Broad Creek.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Broad Creek. 117.233 Section 117.233 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Delaware § 117.233 Broad Creek. (a) The draw of the Conrail...

  4. 81. PHOTOCOPY OF PHOTOGRAPH SHOWING NEW CREEK CHANNEL UNDER CONSTRUCTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    81. PHOTOCOPY OF PHOTOGRAPH SHOWING NEW CREEK CHANNEL UNDER CONSTRUCTION AT P STREET BEND, FROM 1940 REPORT ON PROPOSED DEVELOPMENT OF ROCK CREEK AND POTOMAC PARKWAY, SECTION II (ROCK CREEK AND POTOMAC PARKWAY FILE, HISTORY DEPARTMENT ARCHIVES, NATIONAL PARK SERVICE, WASHINGTON, DC). - Rock Creek & Potomac Parkway, Washington, District of Columbia, DC

  5. Taylor Dispersion Analysis as a promising tool for assessment of peptide-peptide interactions.

    PubMed

    Høgstedt, Ulrich B; Schwach, Grégoire; van de Weert, Marco; Østergaard, Jesper

    2016-10-10

    Protein-protein and peptide-peptide (self-)interactions are of key importance in understanding the physiochemical behavior of proteins and peptides in solution. However, due to the small size of peptide molecules, characterization of these interactions is more challenging than for proteins. In this work, we show that protein-protein and peptide-peptide interactions can advantageously be investigated by measurement of the diffusion coefficient using Taylor Dispersion Analysis. Through comparison to Dynamic Light Scattering it was shown that Taylor Dispersion Analysis is well suited for the characterization of protein-protein interactions of solutions of α-lactalbumin and human serum albumin. The peptide-peptide interactions of three selected peptides were then investigated in a concentration range spanning from 0.5mg/ml up to 80mg/ml using Taylor Dispersion Analysis. The peptide-peptide interactions determination indicated that multibody interactions significantly affect the PPIs at concentration levels above 25mg/ml for the two charged peptides. Relative viscosity measurements, performed using the capillary based setup applied for Taylor Dispersion Analysis, showed that the viscosity of the peptide solutions increased with concentration. Our results indicate that a viscosity difference between run buffer and sample in Taylor Dispersion Analysis may result in overestimation of the measured diffusion coefficient. Thus, Taylor Dispersion Analysis provides a practical, but as yet primarily qualitative, approach to assessment of the colloidal stability of both peptide and protein formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. 1. EXTERIOR OVERVIEW OF NORTH END OF RUSH CREEK POWERHOUSE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR OVERVIEW OF NORTH END OF RUSH CREEK POWERHOUSE RESIDENTIAL COMPLEX SHOWING BUILDING 108 AT PHOTO RIGHT AND BUILDING 105 AT PHOTO CENTER BEHIND TREE. RUSH CREEK POWERHOUSE IS PARTIALLY VISIBLE AT EXTREME PHOTO LEFT). VIEW TO WEST. - Rush Creek Hydroelectric System, Clubhouse Cottage, Rush Creek, June Lake, Mono County, CA

  7. 43 CFR 2091.7-2 - Segregative effect and opening: Taylor Grazing Act.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregative effect and opening: Taylor Grazing Act. 2091.7-2 Section 2091.7-2 Public Lands: Interior Regulations Relating to Public Lands... LAWS AND RULES Segregation and Opening of Lands § 2091.7-2 Segregative effect and opening: Taylor...

  8. 33 CFR 117.841 - Smith Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Smith Creek. 117.841 Section 117.841 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements North Carolina § 117.841 Smith Creek. The draw of the S117-S133...

  9. 33 CFR 117.571 - Spa Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Spa Creek. 117.571 Section 117.571 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.571 Spa Creek. The S181 bridge, mile 4.0, at...

  10. 33 CFR 117.571 - Spa Creek.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Spa Creek. 117.571 Section 117.571 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.571 Spa Creek. The S181 bridge, mile 4.0, at...

  11. Water Quality of Camp Creek, Costello Creek, and Other Selected Streams on the South Side of Denali National Park and Preserve, Alaska

    USGS Publications Warehouse

    Brabets, Timothy P.; Whitman, Matthew S.

    2002-01-01

    The Camp and Costello Creek watersheds are located on the south side of Denali National Park and Preserve. The Dunkle Mine, an abandoned coal mine, is located near the mouth of Camp Creek. Due to concern about runoff from the mine and its possible effects on the water quality and aquatic habitat of Camp Creek and its receiving stream, Costello Creek, these two streams were studied during the summer runoff months (June to September) in 1999 and 2000 as part of a cooperative study with the National Park Service. Since the south side of Denali National Park and Preserve is part of the U.S. Geological Survey?s National Water-Quality Assessment Cook Inlet Basin study unit, an additional part of this study included analysis of existing water-quality data at 23 sites located throughout the south side of Denali National Park and Preserve to compare with the water quality of Camp and Costello Creeks and to obtain a broader understanding of the water quality in this area of the Cook Inlet Basin. Analysis of water column, bed sediment, fish, invertebrate, and algae data indicate no effects on the water quality of Camp Creek from the Dunkle Mine. Although several organic compounds were found in the streambed of Camp Creek, all concentrations were below recommended levels for aquatic life and most of the concentrations were below the minimum reporting level of 50 ?g/kg. Trace element concentrations of arsenic, chromium, and nickel in the bed sediments of Camp Creek exceeded threshold effect concentrations (TEC), but concentrations of these trace elements were also exceeded in streambed sediments of Costello Creek above Camp Creek. Since the percent organic carbon in Camp Creek is relatively high, the toxicity quotient of 0.55 is only slightly above the threshold value of 0.5. Costello Creek has a relatively low organic carbon content and has a higher toxicity quotient of 1.19. Analysis of the water-quality data for other streams located in the south side of Denali National Park

  12. Compression of an Accelerated Taylor State in SSX

    NASA Astrophysics Data System (ADS)

    Shrock, J. E.; Suen-Lewis, E. M.; Barbano, L. J.; Kaur, M.; Schaffner, D. A.; Brown, M. R.

    2017-10-01

    In the Swarthmore Spheromak Experiment (SSX), compact toroidal plasmas are launched from a plasma gun and evolve into minimum energy twisted Taylor states. The plumes initially have a velocity 40 km/s, density 0.4 ×1016 cm-3 , and proton temperature 20 eV . After formation, the plumes are accelerated by pulsed pinch coils with rise times τ1 / 4 = (π / 2) √{ LC } less than 1 μ s and currents Ipeak =V0 / Z =V0 /√{ L / C } on the order of 104 A. The accelerated Taylor States are abruptly stagnated in a copper flux conserver, and over the course of t < 10 μ s, adiabatic compression is observed. The magnetothermodynamics of this compression do not appear to be dictated by the MHD equation of state d / dt (P /nγ) = 0 . Rather, the compression appears to evolve according to the Chew-Goldberger-Low (CGL) double adiabatic model. CGL theory presents two equations of state, one corresponding with particle motion perpendicular to magnetic field in a plasma, the other to particle motion parallel to the field. We observe Taylor state compression most in agreement with the parallel equation of state: d / dt (P∥B2 /n3) = 0 . DOE ARPA-E ALPHA Program.

  13. 77 FR 75946 - Radio Broadcasting Services; Dove Creek, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-26

    ...]. Radio Broadcasting Services; Dove Creek, CO AGENCY: Federal Communications Commission. ACTION: Proposed... service at Dove Creek, Colorado. Channel 229C3 can be allotted at Dove Creek, Colorado, in compliance with the Commission's minimum distance separation requirements, at the proposed reference coordinates: 37...

  14. A Creek to Bay Biological Assessment in Oakland, California

    NASA Astrophysics Data System (ADS)

    Ahumada, E.; Ramirez, N.; Lopez, A.; Avila, M.; Ramirez, J.; Arroyo, D.; Bracho, H.; Casanova, A.; Pierson, E.

    2011-12-01

    In 2007, the Surface Water Ambient Monitoring Program (SWAMP) assessed the impact of trash on water quality in the Peralta Creek which is located in the Fruitvale district of Oakland, CA. This 2011 follow-up study will take further steps in evaluating the physical and biological impacts of pollution and human development on Peralta Creek and in the San Leandro Bay, where the Creek empties into the larger San Francisco Bay estuary. This study will utilize two forms of biological assessment in order to determine the level of water quality and ecosystem health of Peralta Creek and San Leandro Bay in Oakland, California. A Rapid Bioassesment Protocal (RBP) will be used as the method of biological assessment for Peralta Creek. RBP uses a biotic index of benthic macroinvertebrates to provide a measure of a water body's health. Larval trematodes found in two mud snails (Ilynassa obsoleta and Cerithidea californica) will be used to evaluate the health of the San Leandro Bay. Due to the complex life cycle of trematodes, the measure of trematode diversity and richness in host species serves as an indicator of estuarine health (Huspeni 2005). We have completed the assessment of one section of Peralta Creek, located at 2465 34th Avenue, Oakland, CA 94601. Abundance results indicate a moderately healthy creek because there were high levels of pollution tolerant benthic macroinvertebrates. The tolerant group of benthic macroinvertebrates includes such organisms as flatworms, leeches, and scuds. This is possibly due to this section of the creek being pumped up to the surface from culverts impacting the macroinvertebrate's life cycle. Another contributing factor to creek health is the amount of organic debris found in the creek, which inhibits the flow and oxygenation of the water, allowing for more pollution tolerant aquatic insects to persist. Further investigation is being conducted to fully assess the Peralta Creek watershed; from the preliminary results one can surmise that

  15. Nutrients and organic compounds in Deer Creek and south branch Plum Creek in southwestern Pennsylvania, April 1996 through September 1998

    USGS Publications Warehouse

    Williams, D.R.; Clark, M.E.

    2001-01-01

    This report presents results of an analysis of nutrient and pesticide data from two surface-water sites and volatile organic compound (VOC) data from one of the sites that are within the Allegheny and Monongahela River Basins study unit of the National Water-Quality Assessment Program of the U.S. Geological Survey. The Deer Creek site was located in a 27.0 square-mile basin within the Allegheny River Basin in Allegheny County. The primary land uses consist of small urban areas, large areas of residential housing, and some agricultural land in the upper part of the basin. The South Branch Plum Creek site was located in a 33.3 square-mile basin within the Allegheny River Basin in Indiana County. The primary land uses throughout this basin are mostly agriculture and forestland.Water samples for analysis of nutrients were collected monthly and during high-flow events from April 1996 through September 1998. Concentrations of dissolved nitrite, dissolved ammonia plus organic nitrogen, and dissolved phosphorus were less than the method detection limits in more than one-half of the samples collected. The median concentration of dissolved nitrite plus nitrate in South Branch Plum Creek was 0.937 mg/L and 0.597 mg/L in Deer Creek. The median concentration of dissolved orthophosphate was 0.01 mg/L in both streams. High loads of nitrate were measured in both streams from March to June. Concentrations of dissolved ammonia nitrogen, dissolved nitrate, and total phosphorus were lower during the summer months. Measured concentrations of nitrate nitrogen in both streams were well below the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 10 mg/L.Water samples for analysis of pesticides were collected throughout 1997 in both streams and during a storm event on August 25-26, 1998, in Deer Creek. Samples were collected monthly at both sites and more frequently during the spring and early summer months to coincide with application of pesticides. Seventy

  16. Early postcaldera rhyolite and structural resurgence at Long Valley Caldera, California

    NASA Astrophysics Data System (ADS)

    Hildreth, Wes; Fierstein, Judy; Calvert, Andrew

    2017-04-01

    After the 767-ka caldera-forming eruption of 650 km3 of rhyolite magma as the Bishop Tuff, 90-100 km3 of similar rhyolite erupted in the west-central part of Long Valley caldera in as many as 40 batches spread over the 110,000-year interval from 750 ka to 640 ka. Centrally, this Early Rhyolite (ER) is as thick as 622 m, but it spread radially to cover much of the caldera floor, where half its area is now concealed by post-ER sediments and lavas. At least 75% of the ER is aphyric rhyolite tuff. Drillholes encountered 22 (altered) ER lava flows intercalated in the pyroclastic pile, and another 11 units of (largely fresh) ER lava are exposed on the caldera's resurgent dome and at Lookout Mountain. Exposed units have been distinguished, mapped, studied petrographically and chemically, and radioisotopically dated; each is described in detail. Their phenocryst contents range from 0 to 2.5 wt%. All the phyric units have plagioclase, orthopyroxene, and ilmenite; most have biotite and rare tiny magnetite, and a few contain rare zircon. The compositional range of fresh obsidians is narrow-74.3-75.0% SiO2, 1.21-1.37% FeO*, and 5.12-5.26% K2O, but wider variations in Ti, Ba, Sr, and Zr permit distinction of individual units and eruptive groups. The limited chemical and petrographic variability shown by so many ER batches released episodically for 110,000 years suggests a thermally buffered and well-stirred reservoir. The ER central area, where ER eruptions had taken place, was uplifted 400 m to form a structural dome 10 km in diameter. Most of the inflation is attributable to 10 sills of ER that intrude the Bishop Tuff beneath the uplift, but other processes potentially contributing to resurgence are also considered. As shown by erratics of Mesozoic rocks ice-rafted from the Sierra Nevada and dropped on ER lavas, much of the ER had erupted early enough and at low enough elevation to be inundated by the intracaldera lake and was only later lifted by the resurgence that also

  17. Resolving the age of Wilson Creek Formation tephras and the Mono Lake excursion using high-resolution SIMS dating of allanite and zircon rims

    NASA Astrophysics Data System (ADS)

    Vazquez, J. A.; Lidzbarski, M. I.

    2012-12-01

    Sediments of the Wilson Creek Formation surrounding Mono Lake preserve a high-resolution archive of glacial and pluvial responses along the eastern Sierra Nevada due to late Pleistocene climate change. An absolute chronology for the Wilson Creek stratigraphy is critical for correlating the paleoclimate record to other archives in the western U.S. and the North Atlantic region. However, multiple attempts to date the Wilson Creek stratigraphy using carbonates and interbedded rhyolitic tephras yield discordant 14C and 40Ar/39Ar results due to open-system effects, carbon reservoir uncertainties, as well as abundant xenocrysts entrained during eruption. Ion microprobe (SIMS) 238U-230Th dating of the final increments of crystallization recorded by allanite and zircon autocrysts from juvenile pyroclasts yields ages that effectively date eruption of key tephra beds and resolve age uncertainties about the Wilson Creek stratigraphy. To date the final several micrometers of crystal growth, individual allanite and zircon crystals were embedded in soft indium to allow sampling of unpolished rims. Isochron ages derived from rims on coexisting allanite and zircon (± glass) from hand-selected pumiceous pyroclasts delimit the timing of Wilson Creek sedimentation between Ashes 7 and 19 (numbering of Lajoie, 1968) to the interval between ca. 27 to ca. 62 ka. The interiors of individual allanite and zircon crystals sectioned in standard SIMS mounts yield model 238U-230Th ages that are mostly <10 k.y. older than their corresponding rim age, suggesting a relatively brief interval of allanite + zircon crystallization before eruption. A minority of allanite and zircon crystals yield rim and interior model ages of ca. 90-100 ka, and are likely to be antecrysts recycled from relatively early Mono Craters volcanism and/or intrusions. Tephra (Ash 15) erupted during the geomagnetic excursion originally designated the Mono Lake excursion yields a rim isochron age of ca. 41 ka indicating that

  18. Conduit magma convection of a rhyolitic magma: Constraints from cosmic-ray muon radiography of Iwodake, Satsuma-Iwojima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Shinohara, Hiroshi; Tanaka, Hiroyuki K. M.

    2012-10-01

    Quantitative re-evaluation of the muon radiography data obtained by Tanaka et al. (2009) was conducted to constrain conduit magma convection at the Iwodake rhyolitic cone of Satsuma-Iwojima volcano, Japan. Re-evaluation of the measurement error considering topography and fake muon counts confirms the existence of a low-density body of 300 m in diameter and with 0.9-1.0 g cm-3 at depths of 135-190 m from the summit crater floor. The low-density material is interpreted as rhyolitic magma with 60% vesicularity on average, and existence of this unstable highly vesiculated magma at shallow depth without any recent eruptive or intrusive activity is considered as evidence of conduit magma convection. The structure of the convecting magma column top was modeled based on density calculations of vesiculated ascending and outgassed descending magmas, compared with the observed density anomaly. The existence of the low-density anomaly was confirmed by comparison with published gravity measurements, and the predicted degassing at the shallow magma conduit top agrees with observed heat discharge anomaly distribution localized at the summit area. This study confirms that high viscosity of silicic magmas can be compensated by a large size conduit to cause the conduit magma convection phenomena. The rare occurrence of conduit magma convection in a rhyolitic magma system at Iwodake is suggested to be due to its specific magma features of low H2O content and high temperature.

  19. Nonlinear stability of Taylor's vortex array

    NASA Technical Reports Server (NTRS)

    Lin, S. P.; Tobak, M.

    1987-01-01

    It is proved that the two-dimensional Taylor vortex array, which is an exact unsteady solution of the Navier-Stokes equation, is globally and asymptotically stable in the mean with respect to three-dimensional periodic disturbances. A time-dependent bound on the decay rate of the kinetic energy of disturbances is obtained.

  20. 1. DEADWOOD CREEK BRIDGE FACING SOUTHWEST. MOUNT RAINIER AND EMMONS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. DEADWOOD CREEK BRIDGE FACING SOUTHWEST. MOUNT RAINIER AND EMMONS GLACIER VISIBLE IN BACKGROUND. - Deadwood Creek Bridge, Spanning Deadwood Creek on Mather Memorial Parkway, Longmire, Pierce County, WA

  1. Perspective view of span over French Creek and east abutment, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Perspective view of span over French Creek and east abutment, looking NW. - Pennsylvania Railroad, French Creek Trestle, Spanning French Creek, north of Paradise Street, Phoenixville, Chester County, PA

  2. 3. DEADWOOD CREEK BRIDGE, VIEW BELOW DECK SHOWING OPEN SPANDREL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. DEADWOOD CREEK BRIDGE, VIEW BELOW DECK SHOWING OPEN SPANDREL ARCH CONSTRUCTION AND ARCH RIBS - Deadwood Creek Bridge, Spanning Deadwood Creek on Mather Memorial Parkway, Longmire, Pierce County, WA

  3. Effects of potential surface coal mining on dissolved solids in Otter Creek and in the Otter Creek alluvial aquifer, southeastern Montana

    USGS Publications Warehouse

    Cannon, M.R.

    1985-01-01

    Otter Creek drains an area of 709 square miles in the coal-rich Powder River structural basin of southeastern Montana. The Knobloch coal beds in the Tongue River Member of the Paleocene Fort Union Formation is a shallow aquifer and a target for future surface mining in the downstream part of the Otter Creek basin. A mass-balance model was used to estimate the effects of potential mining on the dissolved solids concentration in Otter Creek and in the alluvial aquifer in the Otter Creek valley. With extensive mining of the Knobloch coal beds, the annual load of dissolved solids to Otter Creek at Ashland at median streamflow could increase by 2,873 tons, or a 32-percent increase compared to the annual pre-mining load. Increased monthly loads of Otter Creek, at the median streamflow, could range from 15 percent in February to 208 percent in August. The post-mining dissolved solids load to the subirrigated part of the alluvial valley could increase by 71 percent. The median dissolved solids concentration in the subirrigated part of the valley could be 4,430 milligrams per liter, compared to the pre-mining median concentration of 2,590 milligrams per liter. Post-mining loads from the potentially mined landscape were calculated using saturated-paste-extract data from 506 overburdened samples collected from 26 wells and test holes. Post-mining loads to the Otter Creek valley likely would continue at increased rates for hundreds of years after mining. If the actual area of Knobloch coal disturbed by mining were less than that used in the model, post-mining loads to the Otter Creek valley would be proportionally smaller. (USGS)

  4. 43 CFR 4170.2-1 - Penal provisions under the Taylor Grazing Act.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Penal provisions under the Taylor Grazing Act. 4170.2-1 Section 4170.2-1 Public Lands: Interior Regulations Relating to Public Lands (Continued...-EXCLUSIVE OF ALASKA Penalties § 4170.2-1 Penal provisions under the Taylor Grazing Act. Under section 2 of...

  5. Baseline Characteristics of Jordan Creek, Juneau, Alaska

    USGS Publications Warehouse

    Host, Randy H.; Neal, Edward G.

    2004-01-01

    Anadromous fish populations historically have found healthy habitat in Jordan Creek, Juneau, Alaska. Concern regarding potential degradation to the habitat by urban development within the Mendenhall Valley led to a cooperative study among the City and Borough of Juneau, Alaska Department of Environmental Conservation, and the U.S. Geological Survey, that assessed current hydrologic, water-quality, and physical-habitat conditions of the stream corridor. Periods of no streamflow were not uncommon at the Jordan Creek below Egan Drive near Auke Bay stream gaging station. Additional flow measurements indicate that periods of no flow are more frequent downstream of the gaging station. Although periods of no flow typically were in March and April, streamflow measurements collected prior to 1999 indicate similar periods in January, suggesting that no flow conditions may occur at any time during the winter months. This dewatering in the lower reaches likely limits fish rearing and spawning habitat as well as limiting the migration of juvenile salmon out to the ocean during some years. Dissolved-oxygen concentrations may not be suitable for fish survival during some winter periods in the Jordan Creek watershed. Dissolved-oxygen concentrations were measured as low as 2.8 mg/L at the gaging station and were measured as low as 0.85 mg/L in a tributary to Jordan Creek. Intermittent measurements of pH and dissolved-oxygen concentrations in the mid-reaches of Jordan Creek were all within acceptable limits for fish survival, however, few measurements of these parameters were made during winter-low-flow conditions. One set of water quality samples was collected at six different sites in the Jordan Creek watershed and analyzed for major ions and dissolved nutrients. Major-ion chemistry showed Jordan Creek is calcium bicarbonate type water with little variation between sampling sites.

  6. Sources of baseflow for the Minnehaha Creek Watershed, Minnesota, US

    NASA Astrophysics Data System (ADS)

    Nieber, J. L.; Moore, T. L.; Gulliver, J. S.; Magner, J. A.; Lahti, L. B.

    2013-12-01

    Minnehaha Creek is among the most valued surface water features in the Minneapolis, MN metro area, with a waterfall as it enters the Minnehaha Creek park. Flow in Minnehaha Creek is heavily dependent on discharge from the stream's origin, Lake Minnetonka, the outlet of which is closed during drought periods to maintain water elevations in the lake resulting in low- (or no-) flow conditions in the creek. Stormwater runoff entering directly to the creek from the creek's largely urbanized watershed exacerbates extremes in flow conditions. Given the cultural and ecological value of this stream system, there is great interest in enhancing the cultural and ecosystem services provided by Minnehaha Creek through improvements in streamflow regime by reducing flashiness and sustaining increased low-flows. Determining the potential for achieving improvements in flow requires first that the current sources of water contributing to low-flows in the creek be identified and quantified. Work on this source identification has involved a number of different approaches, including analyses of the streamflow record using a hydrologic system model framework, examination of the Quaternary and bedrock geology of the region, estimation of groundwater-surface water exchange rates within the channel using hyporheic zone temperature surveys and flux meter measurements, and analyses of the stable isotopes of oxygen and hydrogen in samples of stream water, groundwater, and rainfall. Analysis of baseflow recessions using the method of Brutsaert and Nieber (1977) indicates that only a small portion of the catchment, probably the riparian zone, contributes to baseflows. This result appears to be supported by the observation that the limestone/shale bedrock layer underlying the surficial aquifer has a non-zero permeability, and in a significant portion of the watershed the layer has been eroded away leaving the surficial aquifer ';bottomless' and highly susceptible to vertical (down) water loss

  7. Taylor O(h³) Discretization of ZNN Models for Dynamic Equality-Constrained Quadratic Programming With Application to Manipulators.

    PubMed

    Liao, Bolin; Zhang, Yunong; Jin, Long

    2016-02-01

    In this paper, a new Taylor-type numerical differentiation formula is first presented to discretize the continuous-time Zhang neural network (ZNN), and obtain higher computational accuracy. Based on the Taylor-type formula, two Taylor-type discrete-time ZNN models (termed Taylor-type discrete-time ZNNK and Taylor-type discrete-time ZNNU models) are then proposed and discussed to perform online dynamic equality-constrained quadratic programming. For comparison, Euler-type discrete-time ZNN models (called Euler-type discrete-time ZNNK and Euler-type discrete-time ZNNU models) and Newton iteration, with interesting links being found, are also presented. It is proved herein that the steady-state residual errors of the proposed Taylor-type discrete-time ZNN models, Euler-type discrete-time ZNN models, and Newton iteration have the patterns of O(h(3)), O(h(2)), and O(h), respectively, with h denoting the sampling gap. Numerical experiments, including the application examples, are carried out, of which the results further substantiate the theoretical findings and the efficacy of Taylor-type discrete-time ZNN models. Finally, the comparisons with Taylor-type discrete-time derivative model and other Lagrange-type discrete-time ZNN models for dynamic equality-constrained quadratic programming substantiate the superiority of the proposed Taylor-type discrete-time ZNN models once again.

  8. 1. EXTERIOR OVERVIEW OF SOUTH END OF RUSH CREEK POWERHOUSE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR OVERVIEW OF SOUTH END OF RUSH CREEK POWERHOUSE RESIDENTIAL COMPLEX SHOWING THE RUSH CREEK POWERHOUSE AT PHOTO RIGHT (TAILRACE IN FOREGROUND), BUILDING 106 NEXT TO THE POWERHOUSE AT PHOTO LEFT CENTER, AND BUILDING 103 AT UPPER PHOTO LEFT ABOVE AND BEHIND BUILDING 106. VIEW TO SOUTH. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA

  9. Applicability of Taylor's hypothesis in thermally driven turbulence

    NASA Astrophysics Data System (ADS)

    Kumar, Abhishek; Verma, Mahendra K.

    2018-04-01

    In this paper, we show that, in the presence of large-scale circulation (LSC), Taylor's hypothesis can be invoked to deduce the energy spectrum in thermal convection using real-space probes, a popular experimental tool. We perform numerical simulation of turbulent convection in a cube and observe that the velocity field follows Kolmogorov's spectrum (k-5/3). We also record the velocity time series using real-space probes near the lateral walls. The corresponding frequency spectrum exhibits Kolmogorov's spectrum (f-5/3), thus validating Taylor's hypothesis with the steady LSC playing the role of a mean velocity field. The aforementioned findings based on real-space probes provide valuable inputs for experimental measurements used for studying the spectrum of convective turbulence.

  10. "Visit to Caspar Creek, northern California"

    Treesearch

    Nick Schofield

    1989-01-01

    As part of a brief study tour in California, I had the good fortune of spending a very pleasant day on the Caspar Creek watershed, ably guided by Peter Cafferata and Liz Keppeler. Amongst the many notable achievements of the Caspar Creek Study is its longevity. The study started in 1962 and has evolved over time

  11. 27 CFR 9.211 - Swan Creek.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Swan Creek. 9.211 Section 9.211 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.211 Swan Creek. (a) Name. The name of the viticultural are...

  12. Approach view of the Spring Creek Bridge, view looking south. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Approach view of the Spring Creek Bridge, view looking south. - Spring Creek Bridge, Spanning Spring Creek at Milepoint 253.98 on Oregon to California Highway (US Route 97), Chiloquin, Klamath County, OR

  13. Elevation view of the Spring Creek Bridge, view looking east. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Elevation view of the Spring Creek Bridge, view looking east. - Spring Creek Bridge, Spanning Spring Creek at Milepoint 253.98 on Oregon to California Highway (US Route 97), Chiloquin, Klamath County, OR

  14. Approach view of the Spring Creek Bridge, view looking north. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Approach view of the Spring Creek Bridge, view looking north. - Spring Creek Bridge, Spanning Spring Creek at Milepoint 253.98 on Oregon to California Highway (US Route 97), Chiloquin, Klamath County, OR

  15. General perspective view of the Marion Creek Bridge, view looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General perspective view of the Marion Creek Bridge, view looking southwest. - Marion Creek Bridge, Spanning Marion Creek at Milepoint 66.42 on North Santiam Highway (OR-22), Marion Forks, Linn County, OR

  16. General perspective view of the Marion Creek Bridge, view looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General perspective view of the Marion Creek Bridge, view looking southeast. - Marion Creek Bridge, Spanning Marion Creek at Milepoint 66.42 on North Santiam Highway (OR-22), Marion Forks, Linn County, OR

  17. 8. DETAIL VIEW OF DATEPLATE WHICH READS 'HARP CREEK, LUTEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. DETAIL VIEW OF DATEPLATE WHICH READS 'HARP CREEK, LUTEN BRIDGE CO., CONTRACTOR, ARKANSAS STATE HIGHWAY DEPARTMENT, 1928' - Harp Creek Bridge, Spans Harp Creek at State Highway 7, Harrison, Boone County, AR

  18. Probing the volcanic-plutonic connection and the genesis of crystal-rich rhyolite in a deeply dissected supervolcano in the Nevada Great Basin: Source of the late Eocene Caetano Tuff

    USGS Publications Warehouse

    Watts, Kathryn E.; John, David A.; Colgan, Joseph P.; Henry, Christopher D.; Bindeman, Ilya N.; Schmitt, Axel K.

    2016-01-01

    ignimbrite eruption and caldera collapse. Thus, the Caetano Tuff contradicts models for the mutually exclusive origins of voluminous volcanic and plutonic magmas in the upper crust. Crystal-scale O isotope data indicate that the Caetano Tuff is one of the most 18O-enriched rhyolites in the Great Basin (δ18Omagma = 10·2 ± 0·2‰), supporting anatexis of local metasedimentary basement crust. Metapelite xenoliths in the Carico Lake pluton and ubiquitous xenocrystic zircons in the Caetano Tuff provide constraints for the anatexis process; these data point to shallow (<15 km) dehydration melting of a protolith similar to the Proterozoic McCoy Creek Group siliciclastic sediments in eastern Nevada, projected beneath Caetano in fault-stacked shelf sediments that were thickened during Mesozoic crustal shortening. Mean zircon U–Pb ages for different stratigraphic levels of the intra-caldera Caetano Tuff are 34·2–34·5 Ma, 0·2–0·5 Myr older than the caldera sanidine 40Ar/39Ar age of 34·00 ± 0·03 Ma, documenting protracted duration of assembly and homogenization of isotopically diverse upper crustal melts, followed by crystallization and zonation to generate the Caetano Tuff magma chamber. Sanidine rims in the least evolved Caetano Tuff and in the Carico Lake pluton and Redrock Canyon porphyry have sharply zoned Ba domains that point to crystal growth during magmatic recharge events. The recharge magma is inferred to have been compositionally similar to the Caetano Tuff magma, with increased Ba resulting from remelting of Ba-rich sanidine cumulates. Mush reactivation to generate the Caetano Tuff eruption was sufficiently rapid to preserve compositional gradients in the intracaldera ignimbrite, calling into question models that predict homogeneity as a prerequisite for remobilizing crystal-rich ignimbrite magmas.

  19. The Boulder Creek Batholith, Front Range, Colorado

    USGS Publications Warehouse

    Gable, Dolores J.

    1980-01-01

    The Boulder Creek batholith is the best known of several large Precambrian batholiths of similar rock composition that crop out across central Colorado. The rocks in the batholith belong to the calc-alkaline series and range in composition from granodiorite through quartz diorite (tonalite) to gneissic aplite. Two rock types dominate': the Boulder Creek Granodiorite, the major rock unit, and a more leucocratic and slightly younger unit herein named Twin Spruce Quartz Monzonite. Besides mafic inclusions, which occur mainly in hornblende-bearing phases of the Boulder Creek Granodiorite, there are cogenetic older and younger lenses, dikes, and small plutons of hornblende diorite, hornblendite, gabbro, and pyroxenite. Pyroxenite is not found in the batholith. The Boulder Creek Granodiorite in the batholith represents essentially two contemporaneous magmas, a northern body occurring in the Gold Hill and Boulder quadrangles and a larger southern body exposed in the Blackhawk and the greater parts of the Tungsten and Eldorado Springs quadrangles. The two bodies are chemically and mineralogically distinct. The northern body is richer in CaO and poorer in K2O, is more mafic, and has a larger percentage of plagioclase than the southern body. A crude sequence of rock types occurs from west to east in the batholith accompanied by a change in plagioclase composition from calcic plagioclase on the west to sodic on the east. Ore minerals tend to decrease, and the ratio potassium feldspar:plagioclase increases inward from the western contact of the batholith, indicating that the Boulder Creek batholith is similar to granodiorite batholiths the world over. Emplacement of the Boulder Creek batholith was contemporaneous with plastic deformation and high-grade regional metamorphism that folded the country rock and the batholith contact along west-northwest and north-northwest axes. Also, smaller satellitic granodiorite bodies tend to conform to the trends of foliation and fold axes in

  20. Fisheries and aquatic resources of Prairie Creek, Redwood National Park

    USGS Publications Warehouse

    Wilzbach, Peggy; Ozaki, Vicki

    2017-01-01

    This report synthesizes information on the status of fisheries and aquatic resources in the Prairie Creek sub-basin of Redwood Creek in Humboldt County in northern California, founded on a bibliographic search we conducted of historic and current datasets, unpublished reports, theses, and publications. The compiled Prairie Creek Fisheries Bibliography is available at https://irma.nps.gov/DataStore/. This report describes life histories and population status of the salmonid fishes, and species occurrence of non-salmonid fishes, amphibians, macroinvertebrates, and common benthic algae in Prairie Creek. We assessed habitat conditions that may limit salmonid production in relation to recovery targets established by the National Marine Fisheries Service and the State of California. Although salmon abundance has decreased from historic levels, production of juvenile salmonids in Prairie Creek is relatively stable and robust in comparison with the rest of the Redwood Creek Basin. Carrying capacity likely differs between the undisturbed upper reaches of Prairie Creek and reaches in the lower creek, the latter of which are affected by legacy impacts from timber and agricultural activities. Increased sediment supply and lack of channel structure and floodplain connection in lower Prairie Creek appear to be the greatest stressors to salmonid production. Existing datasets on aquatic resources and environmental variables are listed, and subject areas where few data are available are identified.

  1. Frictional Torque Reduction in Taylor-Couette Flows with Riblet-Textured Rotors

    NASA Astrophysics Data System (ADS)

    Raayai, Shabnam; McKinley, Gareth

    2017-11-01

    Inspired by the riblets on the denticles of fast swimming shark species, periodic surface microtextures of different shapes have been studied under laminar and turbulent flow conditions to understand their drag reduction mechanism and to offer guides for designing optimized low-friction bio-inspired surfaces. Various reports over the past four decades have suggested that riblet surfaces can reduce the frictional drag force in high Reynolds number laminar and turbulent flow regimes. Here, we investigate the effect of streamwise riblets on torque reduction in steady flow between concentric cylinders, known as Taylor-Couette Flow. Using 3D printed riblet-textured rotors and a custom-built Taylor-Couette cell which can be mounted on a rheometer we measure the torque on the inner rotor as a function of three different dimensionless parameters; the Reynolds number of the flow, the sharpness of the riblets, and the size of the riblets with respect to the scale of the Taylor-Couette cell. Our experimental results in the laminar viscous flow regime show a reduction in torque up to 10% over a wide range of Reynolds numbers, that is a non-monotonic function of the aspect ratio and independent of Re. However, after transition to the Taylor vortex regime, the modification in torque becomes a function of the Reynolds number, while remaining a non-monotonic function of the aspect ratio. Using finite volume modelling of the geometry we discuss the changes in the Taylor-Couette flow in presence of the riblets compared to the case of smooth rotors and the resulting torque reduction as a function of the parameter space defined above.

  2. 2. GENERAL VIEW SHOWING SIMPSON CREEK BRIDGE WITH BRIDGEPORT LAMP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. GENERAL VIEW SHOWING SIMPSON CREEK BRIDGE WITH BRIDGEPORT LAMP AND CHIMNEY COMPANY IN BACKGROUND. - Bridgeport Lamp Chimney Company, Simpson Creek Bridge, Spanning Simpson Creek, State Route 58 vicinity, Bridgeport, Harrison County, WV

  3. General perspective view of the Spring Creek Bridge, view looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General perspective view of the Spring Creek Bridge, view looking southeast. - Spring Creek Bridge, Spanning Spring Creek at Milepoint 253.98 on Oregon to California Highway (US Route 97), Chiloquin, Klamath County, OR

  4. General perspective view of the Spring Creek Bridge, view looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General perspective view of the Spring Creek Bridge, view looking northwest. - Spring Creek Bridge, Spanning Spring Creek at Milepoint 253.98 on Oregon to California Highway (US Route 97), Chiloquin, Klamath County, OR

  5. General perspective view of the Spring Creek Bridge, view looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General perspective view of the Spring Creek Bridge, view looking east. - Spring Creek Bridge, Spanning Spring Creek at Milepoint 253.98 on Oregon to California Highway (US Route 97), Chiloquin, Klamath County, OR

  6. 1. EXTERIOR OVERVIEW OF SOUTH END OF RUSH CREEK POWERHOUSE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR OVERVIEW OF SOUTH END OF RUSH CREEK POWERHOUSE RESIDENTIAL COMPLEX SHOWING THE RUSH CREEK POWERHOUSE AT PHOTO RIGHT, BUILDING 106 NEXT TO THE POWERHOUSE AT PHOTO CENTER, BUILDING 103 AT UPPER PHOTO LEFT, AND BUILDING 104 ABOVE BUILDING 106 PARTIALLY OBSCURED BEHIND TREE AT UPPER PHOTO CENTER. VIEW TO SOUTH. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA

  7. Ethics, organ donation and tax: a reply to Quigley and Taylor.

    PubMed

    Lippert-Rasmussen, Kasper; Petersen, Thomas Søbirk

    2012-08-01

    A national opt-out system of post-mortem donation of scarce organs is preferable to an opt-in system. Unfortunately, the former system is not always feasible, and so in a recent JME article we canvassed the possibility of offering people a tax break for opting-in as a way of increasing the number of organs available for donation under an opt-in regime. Muireann Quigley and James Stacey Taylor criticize our proposal. Roughly, Quigley argues that our proposal is costly and, hence, is unlikely to be implemented, while Taylor contests our response to a Titmuss-style objection to our scheme. In response to Quigley, we note that our proposal's main attraction lies in gains not reflected in the figures presented by Quigley and that the mere fact that it is costly does not imply that it is unfeasible. In response to Taylor, we offer some textual evidence in support of our interpretation of Taylor and responds to his favoured interpretation of the Titmuss-style objection that many people seem to want to donate to charities even if they can deduct their donations from their income tax. Finally, we show why our views do not commit us to endorsing a free organ-market.

  8. Process development of starch hydrolysis using mixing characteristics of Taylor vortices.

    PubMed

    Masuda, Hayato; Horie, Takafumi; Hubacz, Robert; Ohmura, Naoto; Shimoyamada, Makoto

    2017-04-01

    In food industries, enzymatic starch hydrolysis is an important process that consists of two steps: gelatinization and saccharification. One of the major difficulties in designing the starch hydrolysis process is the sharp change in its rheological properties. In this study, Taylor-Couette flow reactor was applied to continuous starch hydrolysis process. The concentration of reducing sugar produced via enzymatic hydrolysis was evaluated by varying operational variables: rotational speed of the inner cylinder, axial velocity (reaction time), amount of enzyme, and initial starch content in the slurry. When Taylor vortices were formed in the annular space, efficient hydrolysis occurred because Taylor vortices improved the mixing of gelatinized starch with enzyme. Furthermore, a modified inner cylinder was proposed, and its mixing performance was numerically investigated. The modified inner cylinder showed higher potential for enhanced mixing of gelatinized starch and the enzyme than the conventional cylinder.

  9. 1. Topographic view of the Rocky Creek Bridge and the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Topographic view of the Rocky Creek Bridge and the Oregon coast, view looking east - Rocky Creek Bridge, Spanning Rocky Creek on Oregon Coast Highway (U.S. Route 101), Depoe Bay, Lincoln County, OR

  10. Tree ecophysiology research at Taylor Woods

    Treesearch

    Thomas E. Kolb; Nate G. McDowell

    2008-01-01

    We summarize the key findings of tree ecophysiology studies performed at Taylor Woods, Fort Valley Experimental Forest, Arizona between 1994 and 2003 that provide unique insight on impacts of long-term stand density management in ponderosa pine forests on tree water relations, leaf gas exchange, radial growth, leaf area-to-sapwood-area ratio, growth efficiency, leaf...

  11. +2 Valence Metal Concentrations in Lion Creek, Oakland, California

    NASA Astrophysics Data System (ADS)

    Vazquez, P.; Zedd, T.; Chagolla, R.; Dutton-Starbuck, M.; Negrete, A.; Jinham, M.; Lapota, M.

    2012-12-01

    Seven major creeks exist within the City of Oakland, California. These creeks all flow in the southwest direction from forested hills down through densely populated streets where they become susceptible to urban runoff. Lion Creek has been diverted to engineered channels and underground culverts and runs directly under our school (Roots International) before flowing into the San Leandro Bay. One branch of the creek begins near an abandoned sulfur mine. Previous studies have shown that extremely high levels of lead, arsenic and iron exist in this portion of the creek due to acid mine drainage. In this study +2 valence heavy metals concentration data was obtained from samples collected from a segment of the creek located approximately 2.8 miles downstream from the mine. Concentrations in samples collected at three different sites along this segment ranged between 50 ppb and 100 ppb. We hypothesize that these levels are related to the high concentration of +2 valence heavy metals at the mining site. To test this hypothesis, we have obtained samples from various locations along the roughly 3.75 miles of Lion Creek that are used to assess changes in heavy metals concentration levels from the mining site to the San Leandro Bay.

  12. 7. Cable Creek Bridge after completion. Zion National Park negative ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Cable Creek Bridge after completion. Zion National Park negative number 1485, classification series 002, 12. - Floor of the Valley Road, Cable Creek Bridge, Spanning Cable Creek on Floor of Valley, Springdale, Washington County, UT

  13. Topographic view of the Marion Creek Bridge, view looking westbound ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Topographic view of the Marion Creek Bridge, view looking westbound on the Santiam Highway. - Marion Creek Bridge, Spanning Marion Creek at Milepoint 66.42 on North Santiam Highway (OR-22), Marion Forks, Linn County, OR

  14. Three-dimensional single-mode nonlinear ablative Rayleigh-Taylor instability

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yan, R.; Aluie, H.; Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14627

    The nonlinear evolution of the single-mode ablative Rayleigh-Taylor instability is studied in three dimensions. As the mode wavelength approaches the cutoff of the linear spectrum (short-wavelength modes), it is found that the three-dimensional (3D) terminal bubble velocity greatly exceeds both the two-dimensional (2D) value and the classical 3D bubble velocity. Unlike in 2D, the 3D short-wavelength bubble velocity does not saturate. The growing 3D bubble acceleration is driven by the unbounded accumulation of vorticity inside the bubble. The vorticity is transferred by mass ablation from the Rayleigh-Taylor spikes to the ablated plasma filling the bubble volume.

  15. Ferrobasalt-rhyolite immiscibility in tholeiitic volcanic and plutonic series (Invited)

    NASA Astrophysics Data System (ADS)

    Charlier, B.; Namur, O.; Kamenetsky, V. S.; Grove, T. L.

    2013-12-01

    One atmosphere experiments show that silicate liquid immiscibility develops between Fe-rich and Si-rich melts below 1000-1020°C in compositionally diverse lavas that represent classical tholeiitic trends, such as Mull, Iceland, Snake River Plain and Sept Iles. Extreme iron enrichment along the evolution trend is not necessary; immiscibility also develops during iron depletion and silica enrichment after Fe-Ti oxide saturation. Natural liquid lines of descent for major tholeiitic series also approach or intersect the experimentally-defined compositional space of immiscibility. The importance of ferrobasalt-rhyolite unmixing in both volcanic and plutonic environments is supported by worldwide occurrence of immiscible globules in the mesostasis of erupted basalts, and by unmixed melt inclusions in cumulus phases of major layered intrusions such as Sept Iles, Skaergaard and Sudbury. A clear case of liquid immiscibility is also recorded in intrusive tholeiitic gabbros from the Siberian Large Igneous Province and is evidenced by textures and compositions of millimeter-sized silicate melt pools trapped in native iron. An important implication of immiscibility in natural ferrobasaltic provinces is the development of a compositional gap characterized by the absence of intermediate compositions, a major feature observed in many tholeiitic provinces and referred to as the Daly gap. The compositions of experimental silica-rich immiscible melts coincide with those of natural rhyolites with high FeOtot and low Al2O3, which suggests a potential role for large-scale immiscibility in the petrogenesis of late-stage ferroan silicic melts. No evidence for the paired ferrobasaltic melt is observed in volcanic provinces, probably because of its uneruptable characteristics. Instead, Fe-Ti×P-rich gabbros crystallized at depth and are the cumulate products of immiscible Fe-rich melts in plutonic settings, a feature clearly evidenced in the Sept Iles intrusion. The production of

  16. Topographic view of the Spring Creek Bridge and Collier State ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Topographic view of the Spring Creek Bridge and Collier State Park, view looking east. - Spring Creek Bridge, Spanning Spring Creek at Milepoint 253.98 on Oregon to California Highway (US Route 97), Chiloquin, Klamath County, OR

  17. Hulburt Creek Hydrology, Southwestern Wisconsin

    USGS Publications Warehouse

    Gebert, Warren A.

    1971-01-01

    The purpose of this study was to determine the hydrologic characteristics of Hulburt Creek, Sauk County, Wis., in order to evaluate a proposed reservoir. The streamflow characteristics estimated are the low flow, monthly flow, and inflow flood. The study was done by the U.S. Geological Survey in cooperation with the Wisconsin Department of Natural Resources. The following estimates are for the point on Hulburt Creek at the proposed Dell Lake damsite near Wisconsin Dells. The drainage area is 11.2 square miles.

  18. Geologic map of the Simcoe Mountains Volcanic Field, main central segment, Yakama Nation, Washington

    USGS Publications Warehouse

    Hildreth, Wes; Fierstein, Judy

    2015-01-01

    Lava compositions other than various types of basalt are uncommon here. Andesite is abundant on and around Mount Adams but is very rare east of the Klickitat River. The only important nonbasaltic composition in the map area is rhyolite, which crops out in several patches around the central highland of the volcanic field, mainly in the upper canyons of Satus and Kusshi Creeks and Wilson Charley canyon. Because the rhyolites were some of the earliest lavas erupted here, they are widely concealed by later basalts and therefore crop out only in local windows eroded by canyons that cut through the overlying basalts.

  19. The effect of nonlinear decompression history on H2O/CO2 vesiculation in rhyolitic magmas

    NASA Astrophysics Data System (ADS)

    Su, Yanqing; Huber, Christian

    2017-04-01

    Magma ascent rate is one of the key parameters that control volcanic eruption style, tephra dispersion, and volcanic atmospheric impact. Many methods have been employed to investigate the magma ascent rate in volcanic eruptions, and most rely on equilibrium thermodynamics. Combining the mixed H2O-CO2 solubility model with the diffusivities of both H2O and CO2 for normal rhyolitic melt, we model the kinetics of H2O and CO2 in rhyolitic eruptions that involve nonlinear decompression rates. Our study focuses on the effects of the total magma ascent time, the nonlinearity of decompression paths, and the influence of different initial CO2/H2O content on the posteruptive H2O and CO2 concentration profiles around bubbles within the melt. Our results show that, under most circumstances, volatile diffusion profiles do not constrain a unique solution for the decompression rate of magmas during an eruption, but, instead, provide a family of decompression paths with a well-defined trade-off between ascent time and nonlinearity. An important consequence of our analysis is that the common assumption of a constant decompression rate (averaged value) tends to underestimate the actual magma ascent time.

  20. Approach view of the North Fork Butter Creek Bridge, view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Approach view of the North Fork Butter Creek Bridge, view looking south - North Fork Butter Creek Bridge, Spanning North Fork Butter Creek Bridge at Milepost 76.63 on Heppner Highway (Oregon Route 74), Pilot Rock, Umatilla County, OR

  1. Elevation view of the North Fork Butter Creek Bridge, view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Elevation view of the North Fork Butter Creek Bridge, view looking west - North Fork Butter Creek Bridge, Spanning North Fork Butter Creek Bridge at Milepost 76.63 on Heppner Highway (Oregon Route 74), Pilot Rock, Umatilla County, OR

  2. Approach view of the North Fork Butter Creek Bridge, view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Approach view of the North Fork Butter Creek Bridge, view looking north - North Fork Butter Creek Bridge, Spanning North Fork Butter Creek Bridge at Milepost 76.63 on Heppner Highway (Oregon Route 74), Pilot Rock, Umatilla County, OR

  3. Estimating pothole wetland connectivity to Pipestem Creek ...

    EPA Pesticide Factsheets

    Understanding hydrologic connectivity between wetlands and perennial streams is critical to understanding how reliant stream flow is on wetlands within their watershed. We used the isotopic evaporation signal in water to examine hydrologic connectivity within Pipestem Creek, North Dakota, with a watershed dominated by prairie potholes. During a decadal period of wet conditions, Pipestem Creek contained evaporated water that had approximately half the isotopic evaporative enrichment signal found in most evaporated permanent wetlands. If evaporation was mainly occurring within the stream, we expected the evaporation signal to increase from the headwaters with distance downstream. However, the signal either remained similar or decreased downstream over the two years of sampling. Groundwater measured at the water table adjacent to Pipestem Creek had isotopic values that indicated recharge from winter precipitation and had no significant evaporation. Using isotopic theory and discharge data, we estimated the surface area of open water necessary to generate the evaporation signal found within Pipestem Creek over time. The range of evaporating surface-area estimates was highly dynamic, spanning from 43 to 2653 ha and varying primarily with discharge. The average value (just over 600 ha) was well above the surface area of Pipestem Creek network (245 ha). This estimate of contributing area indicated that Prairie Pothole wetlands were important sources of stream fl

  4. A Simple Model for the Viscosity of Rhyolites as a Function of Temperature, Pressure and Water Content: Implications for Obsidian Flow Emplacement

    NASA Astrophysics Data System (ADS)

    Whittington, A. G.; Romine, W. L.

    2014-12-01

    Understanding the dynamics of rhyolitic conduits and lava flows, requires precise knowledge of how viscosity (η) varies with temperature (T), pressure (P) and volatile content (X). In order to address the paucity of viscosity data for high-silica rhyolite at low water contents, which represent water saturation at near-surface conditions, we made 245 viscosity measurements on Mono Craters (California) rhyolites containing between 0.01 and 1.1 wt.% H2O, at temperatures between 796 and 1774 K using parallel plate and concentric cylinder methods at atmospheric pressure. We then developed and calibrated a new empirical model for the log of the viscosity of rhyolitic melts, where non-linear variations due to temperature and water content are nested within a linear dependence of log η on P. The model was fitted to a total of 563 data points: our 245 new data, 255 published data from rhyolites across a wide P-T-X space, and 63 data on haplogranitic and granitic melts under high P-T conditions. Statistically insignificant parameters were eliminated from the model in an effort to increase parsimony and the final model is simple enough for use in numerical models of conduit or lava flow dynamics: log η = -5.142+(13080-2982log⁡(w+0.229))/(T-(98.9-175.9 log⁡(w+0.229)))- P(0.0007-0.76/T ) where η is in Pa s, w is water content in wt.%, P is in MPa and T is in K. The root mean square deviation (rmsd) between the model predictions and the 563 data points used in calibration is 0.39 log units. Experimental constraints have led previously to spurious correlations between P, T, X and η in viscosity data sets, so that predictive models may struggle to correctly resolve the individual effects of P, T and X, and especially their cross-correlations. The increasing water solubility with depth inside a simple isothermal sheet of obsidian suggests that viscosity should decrease by ~1 order of magnitude at ~20m depth and by ~2 orders of magnitude at ~100m depth. If equilibrium water

  5. General perspective view of the North Fork Butter Creek Bridge, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General perspective view of the North Fork Butter Creek Bridge, view looking southwest - North Fork Butter Creek Bridge, Spanning North Fork Butter Creek Bridge at Milepost 76.63 on Heppner Highway (Oregon Route 74), Pilot Rock, Umatilla County, OR

  6. General perspective view of the North Fork Butter Creek Bridge, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General perspective view of the North Fork Butter Creek Bridge, view looking north - North Fork Butter Creek Bridge, Spanning North Fork Butter Creek Bridge at Milepost 76.63 on Heppner Highway (Oregon Route 74), Pilot Rock, Umatilla County, OR

  7. Detail perspective view of the North Fork Butter Creek Bridge, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail perspective view of the North Fork Butter Creek Bridge, view looking southwest - North Fork Butter Creek Bridge, Spanning North Fork Butter Creek Bridge at Milepost 76.63 on Heppner Highway (Oregon Route 74), Pilot Rock, Umatilla County, OR

  8. General perspective view of the North Fork Butter Creek Bridge, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General perspective view of the North Fork Butter Creek Bridge, view looking south - North Fork Butter Creek Bridge, Spanning North Fork Butter Creek Bridge at Milepost 76.63 on Heppner Highway (Oregon Route 74), Pilot Rock, Umatilla County, OR

  9. Advection and Taylor-Aris dispersion in rivulet flow

    NASA Astrophysics Data System (ADS)

    Al Mukahal, F. H. H.; Duffy, B. R.; Wilson, S. K.

    2017-11-01

    Motivated by the need for a better understanding of the transport of solutes in microfluidic flows with free surfaces, the advection and dispersion of a passive solute in steady unidirectional flow of a thin uniform rivulet on an inclined planar substrate driven by gravity and/or a uniform longitudinal surface shear stress are analysed. Firstly, we describe the short-time advection of both an initially semi-infinite and an initially finite slug of solute of uniform concentration. Secondly, we describe the long-time Taylor-Aris dispersion of an initially finite slug of solute. In particular, we obtain the general expression for the effective diffusivity for Taylor-Aris dispersion in such a rivulet, and discuss in detail its different interpretations in the special case of a rivulet on a vertical substrate.

  10. Water quality, sources of nitrate, and chemical loadings in the Geronimo Creek and Plum Creek watersheds, south-central Texas, April 2015–March 2016

    USGS Publications Warehouse

    Lambert, Rebecca B.; Opsahl, Stephen P.; Musgrove, MaryLynn

    2017-12-22

    Located in south-central Texas, the Geronimo Creek and Plum Creek watersheds have long been characterized by elevated nitrate concentrations. From April 2015 through March 2016, an assessment was done by the U.S. Geological Survey, in cooperation with the Guadalupe-Blanco River Authority and the Texas State Soil and Water Conservation Board, to characterize nitrate concentrations and to document possible sources of elevated nitrate in these two watersheds. Water-quality samples were collected from stream, spring, and groundwater sites distributed across the two watersheds, along with precipitation samples and wastewater treatment plant (WWTP) effluent samples from the Plum Creek watershed, to characterize endmember concentrations and isotopic compositions from April 2015 through March 2016. Stream, spring, and groundwater samples from both watersheds were collected during four synoptic sampling events to characterize spatial and temporal variations in water quality and chemical loadings. Water-quality and -quantity data from the WWTPs and stream discharge data also were considered. Samples were analyzed for major ions, selected trace elements, nutrients, and stable isotopes of water and nitrate.The dominant land use in both watersheds is agriculture (cultivated crops, rangeland, and grassland and pasture). The upper part of the Plum Creek watershed is more highly urbanized and has five major WWTPs; numerous smaller permitted wastewater outfalls are concentrated in the upper and central parts of the Plum Creek watershed. The Geronimo Creek watershed, in contrast, has no WWTPs upstream from or near the sampling sites.Results indicate that water quality in the Geronimo Creek watershed, which was evaluated only during base-flow conditions, is dominated by groundwater, which discharges to the stream by numerous springs at various locations. Nitrate isotope values for most Geronimo Creek samples were similar, which indicates that they likely have a common source (or

  11. 1. EXTERIOR OVERVIEW SHOWING BISHOP CREEK PLANT 4 RESIDENTIAL COMPLEX. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR OVERVIEW SHOWING BISHOP CREEK PLANT 4 RESIDENTIAL COMPLEX. BUILDING 122 IS VISIBLE AT PHOTO CENTER. PLANT 5 INTAKE DAM AT PHOTO LEFT. VIEW TO WEST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

  12. View looking Eastnortheast at French Creek trestle, which appears at ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View looking Eastnortheast at French Creek trestle, which appears at left center of frame. Bridge in foreground is west entrance to abandoned Phoenix iron works. - Pennsylvania Railroad, French Creek Trestle, Spanning French Creek, north of Paradise Street, Phoenixville, Chester County, PA

  13. 33 CFR 117.153 - Corte Madera Creek.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Corte Madera Creek. 117.153 Section 117.153 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.153 Corte Madera Creek. The draw of...

  14. 33 CFR 117.153 - Corte Madera Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Corte Madera Creek. 117.153 Section 117.153 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.153 Corte Madera Creek. The draw of...

  15. Nonideal Rayleigh–Taylor mixing

    PubMed Central

    Lim, Hyunkyung; Iwerks, Justin; Glimm, James; Sharp, David H.

    2010-01-01

    Rayleigh–Taylor mixing is a classical hydrodynamic instability that occurs when a light fluid pushes against a heavy fluid. The two main sources of nonideal behavior in Rayleigh–Taylor (RT) mixing are regularizations (physical and numerical), which produce deviations from a pure Euler equation, scale invariant formulation, and nonideal (i.e., experimental) initial conditions. The Kolmogorov theory of turbulence predicts stirring at all length scales for the Euler fluid equations without regularization. We interpret mathematical theories of existence and nonuniqueness in this context, and we provide numerical evidence for dependence of the RT mixing rate on nonideal regularizations; in other words, indeterminacy when modeled by Euler equations. Operationally, indeterminacy shows up as nonunique solutions for RT mixing, parametrized by Schmidt and Prandtl numbers, in the large Reynolds number (Euler equation) limit. Verification and validation evidence is presented for the large eddy simulation algorithm used here. Mesh convergence depends on breaking the nonuniqueness with explicit use of the laminar Schmidt and Prandtl numbers and their turbulent counterparts, defined in terms of subgrid scale models. The dependence of the mixing rate on the Schmidt and Prandtl numbers and other physical parameters will be illustrated. We demonstrate numerically the influence of initial conditions on the mixing rate. Both the dominant short wavelength initial conditions and long wavelength perturbations are observed to play a role. By examination of two classes of experiments, we observe the absence of a single universal explanation, with long and short wavelength initial conditions, and the various physical and numerical regularizations contributing in different proportions in these two different contexts. PMID:20615983

  16. 20. DISTANT HELICOPTER VIEW TO SOUTHEAST UP LITTLE ROCK CREEK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. DISTANT HELICOPTER VIEW TO SOUTHEAST UP LITTLE ROCK CREEK CANYON, WITH DAM AND RESERVOIR AT RIGHT CENTER. PALMDALE-LITTLEROCK DITCH, MARKED BY DENSE VEGETATION, CROSSES ROAD AT LOWER CENTER - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

  17. 1. EXTERIOR OVERVIEW SHOWING BISHOP CREEK PLANT 4 RESIDENTIAL COMPLEX. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR OVERVIEW SHOWING BISHOP CREEK PLANT 4 RESIDENTIAL COMPLEX. BUILDING 113 IS VISIBLE AT RIGHT PHOTO CENTER. PLANT 5 INTAKE DAM AT PHOTO LEFT. VIEW TO WEST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

  18. Topographic view of the North Fork Butter Creek Bridge (located ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Topographic view of the North Fork Butter Creek Bridge (located center of frame), view looking west - North Fork Butter Creek Bridge, Spanning North Fork Butter Creek Bridge at Milepost 76.63 on Heppner Highway (Oregon Route 74), Pilot Rock, Umatilla County, OR

  19. Taylor instability in the shock layer on a Jovian atmosphere entry probe.

    NASA Technical Reports Server (NTRS)

    Compton, D. L.

    1972-01-01

    Investigation of the Taylor instability relative to the dynamical instability whose presence in the shock layer on a spacecraft entering the Jovian atmosphere is to be expected because of the difference in velocity across the shear layer. Presented calculations show that the Taylor instability at the interface between shock-heated freestream gas and ablation products is inconsequential in comparison to the shear layer instability.

  20. 33 CFR 117.1001 - Cat Point Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Cat Point Creek. 117.1001 Section 117.1001 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Virginia § 117.1001 Cat Point Creek. The draw of the...

  1. 33 CFR 117.800 - Mill Neck Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Mill Neck Creek. 117.800 Section 117.800 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117.800 Mill Neck Creek. The draw of the...

  2. 33 CFR 117.705 - Beaver Dam Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Beaver Dam Creek. 117.705 Section 117.705 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.705 Beaver Dam Creek. The draw of the...

  3. 33 CFR 117.705 - Beaver Dam Creek.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Beaver Dam Creek. 117.705 Section 117.705 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.705 Beaver Dam Creek. The draw of the...

  4. 33 CFR 334.240 - Potomac River, Mattawoman Creek and Chicamuxen Creek; U.S. Naval Surface Weapons Center, Indian...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Potomac River, Mattawoman Creek..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.240 Potomac River, Mattawoman Creek...) The danger zone. Beginning at a point on the easterly shore of the Potomac River at latitude 38°36′00...

  5. 33 CFR 334.240 - Potomac River, Mattawoman Creek and Chicamuxen Creek; U.S. Naval Surface Weapons Center, Indian...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Potomac River, Mattawoman Creek..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.240 Potomac River, Mattawoman Creek...) The danger zone. Beginning at a point on the easterly shore of the Potomac River at latitude 38°36′00...

  6. 33 CFR 334.240 - Potomac River, Mattawoman Creek and Chicamuxen Creek; U.S. Naval Surface Weapons Center, Indian...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Potomac River, Mattawoman Creek..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.240 Potomac River, Mattawoman Creek...) The danger zone. Beginning at a point on the easterly shore of the Potomac River at latitude 38°36′00...

  7. 33 CFR 334.240 - Potomac River, Mattawoman Creek and Chicamuxen Creek; U.S. Naval Surface Weapons Center, Indian...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Potomac River, Mattawoman Creek..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.240 Potomac River, Mattawoman Creek...) The danger zone. Beginning at a point on the easterly shore of the Potomac River at latitude 38°36′00...

  8. 33 CFR 334.240 - Potomac River, Mattawoman Creek and Chicamuxen Creek; U.S. Naval Surface Weapons Center, Indian...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Potomac River, Mattawoman Creek..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.240 Potomac River, Mattawoman Creek...) The danger zone. Beginning at a point on the easterly shore of the Potomac River at latitude 38°36′00...

  9. Calibration of streamflow gauging stations at the Tenderfoot Creek Experimental Forest

    Treesearch

    Scott W. Woods

    2007-01-01

    We used tracer based methods to calibrate eleven streamflow gauging stations at the Tenderfoot Creek Experimental Forest in western Montana. At six of the stations the measured flows were consistent with the existing rating curves. At Lower and Upper Stringer Creek, Upper Sun Creek and Upper Tenderfoot Creek the published flows, based on the existing rating curves,...

  10. Persistence of the longnose darter (P. nasuta) in Lee Creek, Oklahoma

    USGS Publications Warehouse

    Gatlin, Michael R.; Long, James M.

    2011-01-01

    Lee Creek is one of Oklahoma’s six rivers designated as "scenic" by the Oklahoma Legislature. Lee Creek is located on the Oklahoma-Arkansas border in far eastern Oklahoma. The headwaters originate in northwestern Arkansas and flow south towards the Arkansas River. While the majority of the stream is in Arkansas, a portion flows into Oklahoma northwest of Uniontown, AR and continues for 28.2 river-km before crossing back into Arkansas near Van Buren, AR. The hydrology of lower Lee Creek has been altered by Lee Creek Reservoir near Van Buren, AR. It was believed that pre-impounded Lee Creek had the largest existing population of longnose darters (8). However, the most recent fish surveys in Lee Creek were conducted approximately twenty years ago. Robinson (8) surveyed Lee Creek in Arkansas, upstream of the Oklahoma border, and found longnose darters upstream of Natural Dam, AR. Wagner et al. (10) were the last to document longnose darter presence in the Oklahoma segment of Lee Creek. No efforts to collect this species in Oklahoma have occurred since the completion of Lee Creek Reservoir. Our objective was to determine whether the species persist in this segment of its historic range since impoundment.

  11. Shallow Sub-Permafrost Groundwater Systems In A Buried Fjord: Taylor Valley, Antarctica

    NASA Astrophysics Data System (ADS)

    Foley, N.; Tulaczyk, S. M.; Auken, E.; Mikucki, J.

    2014-12-01

    The McMurdo Dry Valleys (MDV), Antarctica, represent a unique geologic setting where permanent lakes, ephemeral streams, and subglacial waters influence surface hydrology in a cold polar desert. Past research suggested that the MDV are underlain by several hundreds of meters of permafrost. Here, we present data collected from an Airborne EM (AEM) resistivity sensor flown over the MDV during the 2011-12 austral summer. A focus of our survey was over the Taylor Glacier where saline, iron-rich subglacial fluid releases at the glacier snout at a feature known as Blood Falls, and over Taylor Valley, where a series of isolated lakes lie between Taylor Glacier and the Ross Sea. Our data show that in Taylor Valley there are extensive areas of low resistivity, interpreted as hypersaline brines, beneath a relatively thin layer of high resistivity material, interpreted as dry- or ice-cemented permafrost. These hypersaline brines remain liquid at temperatures well below 0°C due to their salinity. They appear to be contained within the sedimentary fill deposited in Taylor Valley when it was still a fjord. This brine system continues up valley and has a subglacial extension beneath Taylor Glacier, where it may provide the source that feeds Blood Falls. By categorizing the resistivity measurements according to surficial land cover, we are able to distinguish between ice, permafrost, lake water, and seawater based on characteristic resistivity distributions. Furthermore, this technique shows that areas of surface permafrost become increasingly conductive (brine-filled) with depth, whereas the large lakes exhibit taliks that extend through the entire thickness of the permafrost. The subsurface brines represent a large, unstudied and potentially connected hydrogeologic system, in which subsurface flows may help transfer water and nutrients between lakes in the MDV and into the Ross Sea. Such a system is a potential habitat for extremophile life, similar to that already detected in

  12. The roles of fractional crystallization, magma mixing, crystal mush remobilization and volatile-melt interactions in the genesis of a young basalt-peralkaline rhyolite suite, the greater Olkaria volcanic complex, Kenya Rift valley

    USGS Publications Warehouse

    Macdonald, R.; Belkin, H.E.; Fitton, J.G.; Rogers, N.W.; Nejbert, K.; Tindle, A.G.; Marshall, A.S.

    2008-01-01

    The Greater Olkaria Volcanic Complex is a young (???20 ka) multi-centred lava and dome field dominated by the eruption of peralkaline rhyolites. Basaltic and trachytic magmas have been erupted peripherally to the complex and also form, with mugearites and benmoreites, an extensive suite of magmatic inclusions in the rhyolites. The eruptive rocks commonly represent mixed magmas and the magmatic inclusions are themselves two-, three- or four-component mixes. All rock types may carry xenocrysts of alkali feldspar, and less commonly plagioclase, derived from magma mixing and by remobilization of crystal mushes and/or plutonic rocks. Xenoliths in the range gabbro-syenite are common in the lavas and magmatic inclusions, the more salic varieties sometimes containing silicic glass representing partial melts and ranging in composition from anorthite ?? corundum- to acmite-normative. The peralkaline varieties are broadly similar, in major element terms, to the eruptive peralkaline rhyolites. The basalt-trachyte suite formed by a combination of fractional crystallization, magma mixing and resorption of earlier-formed crystals. Matrix glass in metaluminous trachytes has a peralkaline rhyolitic composition, indicating that the eruptive rhyolites may have formed by fractional crystallization of trachyte. Anomalous trace element enrichments (e.g. ??? 2000 ppm Y in a benmoreite) and negative Ce anomalies may have resulted from various Na- and K-enriched fluids evolving from melts of intermediate composition and either being lost from the system or enriched in other parts of the reservoirs. A small group of nepheline-normative, usually peralkaline, magmatic inclusions was formed by fluid transfer between peralkaline rhyolitic and benmoreitic magmas. The plumbing system of the complex consists of several independent reservoirs and conduits, repeatedly recharged by batches of mafic magma, with ubiquitous magma mixing. ?? The Author 2008. Published by Oxford University Press. All

  13. Three-dimensional single-mode nonlinear ablative Rayleigh-Taylor instability

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yan, R.; Betti, R.; Sanz, J.

    The nonlinear evolution of the single-mode ablative Rayleigh-Taylor instability is studied in three dimensions. As the mode wavelength approaches the cutoff of the linear spectrum (short-wavelength modes), it is found that the three-dimensional (3D) terminal bubble velocity greatly exceeds both the two-dimensional (2D) value and the classical 3D bubble velocity. Unlike in 2D, the 3D short-wavelength bubble velocity does not saturate. The growing 3D bubble acceleration is driven by the unbounded accumulation of vorticity inside the bubble. As a result, the vorticity is transferred by mass ablation from the Rayleigh-Taylor spikes to the ablated plasma filling the bubble volume.

  14. A numerical simulation of finite-length Taylor-Couette flow

    NASA Technical Reports Server (NTRS)

    Streett, C. L.; Hussaini, M. Y.

    1987-01-01

    The processes leading to laminar-turbulent transition in finite-channel-length Taylor-Couette flow are investigated analytically, solving the unsteady incompressible Navier-Stokes equations by spectral-collocation methods. A time-split algorithm, implementable in both axisymmetric and fully three-dimensional time-accurate versions, and an algorithm based on the staggered-mesh discretization of Bernardi and Maday (1986) are described in detail, and results obtained by applying the axisymmetric version of the first algorithm and a steady-state version of the second are presented graphically and compared with published experimental data. The feasibility of full three-dimensional simulations of the progression through chaotic states to turbulence under the constraints of Taylor-Couette flow is demonstrated.

  15. A Taylor weak-statement algorithm for hyperbolic conservation laws

    NASA Technical Reports Server (NTRS)

    Baker, A. J.; Kim, J. W.

    1987-01-01

    Finite element analysis, applied to computational fluid dynamics (CFD) problem classes, presents a formal procedure for establishing the ingredients of a discrete approximation numerical solution algorithm. A classical Galerkin weak-statement formulation, formed on a Taylor series extension of the conservation law system, is developed herein that embeds a set of parameters eligible for constraint according to specification of suitable norms. The derived family of Taylor weak statements is shown to contain, as special cases, over one dozen independently derived CFD algorithms published over the past several decades for the high speed flow problem class. A theoretical analysis is completed that facilitates direct qualitative comparisons. Numerical results for definitive linear and nonlinear test problems permit direct quantitative performance comparisons.

  16. 1. EXTERIOR OVERVIEW SHOWING BISHOP CREEK PLANT 4 RESIDENTIAL COMPLEX. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR OVERVIEW SHOWING BISHOP CREEK PLANT 4 RESIDENTIAL COMPLEX. ROOF OF BUILDING 105 IS VISIBLE IN UPPER PHOTO CENTER. PLANT 5 INTAKE DAM AT PHOTO LEFT. VIEW TO WEST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

  17. 33 CFR 110.72 - Blackhole Creek, Md.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Blackhole Creek, Md. 110.72 Section 110.72 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.72 Blackhole Creek, Md. The waters on the west side of...

  18. 33 CFR 110.72 - Blackhole Creek, Md.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Blackhole Creek, Md. 110.72 Section 110.72 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.72 Blackhole Creek, Md. The waters on the west side of...

  19. Tidal creek changes at the Sonoma Baylands restoration site

    USGS Publications Warehouse

    Dingler, John R.; Cacchione, David A.; ,

    1998-01-01

    Over the past 150 years, human activity has had a major impact on tidal wetlands adjoining the San Francisco Bay-Delta estuary Growing concern about the effect of this change on the ecology of the estuary has prompted Bay area managers to attempt to reclaim tidal wetlands. The Sonoma Baylands Restoration Project is designed to use dredge material to convert 348 acres from farmland to wetland. This paper describes changes to a tidal creek that flows from that restoration site to San Pablo Bay (north San Francisco Bay) through an existing tidal wetland during different phases of the project. Hydrologic measurements near the bottom of the creek and cross-creek profiles show how the creek responded to non-tidal flow conditions introduced by filling the site with dredge materials. At the time of this study, the creek had deepened by approximately 40 cm but had not widened.

  20. Ekman-Hartmann layer in a magnetohydrodynamic Taylor-Couette flow

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Szklarski, Jacek; Ruediger, Guenther

    2007-12-15

    We study magnetic effects induced by rigidly rotating plates enclosing a cylindrical magnetohydrodynamic (MHD) Taylor-Couette flow at the finite aspect ratio H/D=10. The fluid confined between the cylinders is assumed to be liquid metal characterized by small magnetic Prandtl number, the cylinders are perfectly conducting, an axial magnetic field is imposed with Hartmann number Ha{approx_equal}10, and the rotation rates correspond to Reynolds numbers of order 10{sup 2}-10{sup 3}. We show that the end plates introduce, besides the well-known Ekman circulation, similar magnetic effects which arise for infinite, rotating plates, horizontally unbounded by any walls. In particular, there exists the Hartmannmore » current, which penetrates the fluid, turns in the radial direction, and together with the applied magnetic field gives rise to a force. Consequently, the flow can be compared with a Taylor-Dean flow driven by an azimuthal pressure gradient. We analyze the stability of such flows and show that the currents induced by the plates can give rise to instability for the considered parameters. When designing a MHD Taylor-Couette experiment, special care must be taken concerning the vertical magnetic boundaries so that they do not significantly alter the rotational profile.« less

  1. Caspar Creek

    Treesearch

    Robert R. Ziemer

    2001-01-01

    The USDA Forest Service Pacific Southwest Research Station and the California Department of Forestry and Fire Protection have gauged streamflow, and suspended sediment and precipitation since 1962 in the 473 ha North Fork and the 424 ha South Fork of the 2167 ha Caspar Creek in the Jackson Demonstation State Forest in northwestern California. Within the two Caspar...

  2. Characterization of Fish Creek, Teton County, Wyoming, 2004-08

    USGS Publications Warehouse

    Eddy-Miller, Cheryl A.; Peterson, David A.; Wheeler, Jerrod D.; Leemon, Daniel J.

    2010-01-01

    Fish Creek, a tributary to the Snake River, is about 15 river miles long and is located in Teton County in western Wyoming near the town of Wilson (fig. 1). Public concern about nuisance growths of aquatic plants in Fish Creek has been increasing since the early 2000s. To address this concern, the U.S. Geological Survey, in cooperation with the Teton Conservation District, began studying Fish Creek in 2004 to describe the hydrology of the creek and later (2007?08) to characterize the water quality and the biological communities. The purpose of this fact sheet is to summarize the study results from 2004 to 2008.

  3. Comments on ;Geochronology and geochemistry of rhyolites from Hormuz Island, southern Iran: A new Cadomian arc magmatism in the Hormuz Formationˮ by N. S. Faramarzi, S. Amini, A. K. Schmitt, J. Hassanzadeh, G. Borg, K. McKeegan, S. M. H. Razavi, S. M. Mortazavi, Lithos, Sep. 2015, V.236-237, P.203-211: A missing link of Ediacaran A-type rhyolitic volcanism associated with glaciogenic banded iron salt formation (BISF)

    NASA Astrophysics Data System (ADS)

    Atapour, Habibeh; Aftabi, Alijan

    2017-07-01

    A critical overview on the petrogeochemistry of Hormuz Island highlights that the Ediacaran Hormuz Complex includes synchronous felsic submarine volcanism associated with diamictite and dropstone-bearing banded iron salt (anhydrite, halite, sylvite) formation (BISF) that formed 558-541 Ma in the Late Neoproterozoic. Our field observations disagree with Faramarzi et al. (2015) on the geological map of the Hormuz Island, in particular on the occurrence of the ferruginous agglomerates in the Hormuz Island, thus the geological data do not provide a robust geological mapping. The agglomerates are commonly related to the strombolian peralkaline basaltic eruptions rather than the submarine felsic volcanism. Based on the tectonogeochemical diagrams extracted from the geochemical data of the authors, the Hormuz rhyolites show an affinity to the A-type or A2-type submarine riftogenic and or intra-plate rhyolites of Eby (1992). However, the authors admitted two sides of the debate and proposed an extensional back arc or rift-related magmatic activity as well as continental arc margin setting. The rhyolites are also similar to the Ediacaran Arabian-Nubian A-type alkaline rhyolites that formed by intra-plate rifting during the Pan-African orogen in the proto-Tethys shallow grabens of the Gondwana supercontinent. The most exceptional feature of the Hormuz rhyolites is related to their co-occurrence with the Ediacaran salt rocks, glaciogenic diamictites and jaspillitic banded iron formations, which have never ever been reported previously.

  4. Estimating pothole wetland connectivity to Pipestem Creek ...

    EPA Pesticide Factsheets

    Understanding hydrologic connectivity between wetlands and perennial streams is critical to understanding how reliant stream flow is on wetlands within their watershed. We used the isotopic evaporation signal in water to examine wetland-stream hydrologic connectivity within the Pipestem Creek watershed, North Dakota, a watershed dominated by prairie-pothole wetlands. During a wetter-than-normal decade, Pipestem Creek exhibited an evaporated-water signal that had approximately half the isotopic-enrichment signal found in most evaporatively enriched pothole wetlands. If evaporation was mainly occurring within the stream, we expected the evaporation signal to increase from upstream towards downstream. However, the signal either remained similar or decreased downstream over the two years of sampling. Groundwater measured at the water table adjacent to Pipestem Creek had isotopic values that indicated recharge from winter precipitation and had no significant evaporative enrichment. Using isotopic theory and discharge data, we estimated the surface area of open water necessary to generate the evaporation signal found within Pipestem Creek over time. The range of evaporating surface-area estimates was highly dynamic, spanning from 35 to 2380 ha of open water contributing to streamflow over time, and varied primarily with the amount of discharge. The median value (417 ha) was well above the surface area of the Pipestem Creek network (245 ha), and only two periods

  5. Environmental setting of Maple Creek watershed, Nebraska

    USGS Publications Warehouse

    Fredrick, Brian S.; Linard, Joshua I.; Carpenter, Jennifer L.

    2006-01-01

    The Maple Creek watershed covers a 955-square-kilometer area in eastern Nebraska, which is a region dominated by agricultural land use. The Maple Creek watershed is one of seven areas currently included in a nationwide study of the sources, transport, and fate of water and chemicals in agricultural watersheds. This study, known as the topical study of 'Agricultural Chemicals: Sources, Transport, and Fate' is part of the National Water-Quality Assessment Program being conducted by the U.S. Geological Survey. The Program is designed to describe water-quality conditions and trends based on representative surface- and ground-water resources across the Nation. The objective of the Agricultural Chemicals topical study is to investigate the sources, transport, and fate of selected agricultural chemicals in a variety of agriculturally diverse environmental settings. The Maple Creek watershed was selected for the Agricultural Chemicals topical study because its watershed represents the agricultural setting that characterizes eastern Nebraska. This report describes the environmental setting of the Maple Creek watershed in the context of how agricultural practices, including agricultural chemical applications and irrigation methods, interface with natural settings and hydrologic processes. A description of the environmental setting of a subwatershed within the drainage area of Maple Creek is included to improve the understanding of the variability of hydrologic and chemical cycles at two different scales.

  6. McMurdo LTER: streamflow measurements in Taylor Valley

    USGS Publications Warehouse

    McKnight, D.; House, H.; Von Guerard, P.

    1994-01-01

    Has established a stream gaging network for the three major lake basins in Taylor Valley. These data are critical for determining nutrient budgets for the lake ecosystems and for understanding physical factors controlling microbial mats in the streams.

  7. Vertical Structural Variation and Their Development of the Sanukayama Rhyolite Lava in Kozushima Island, Japan

    NASA Astrophysics Data System (ADS)

    Furukawa, K.; Uno, K.; Kanamaru, T.; Nakai, K.

    2017-12-01

    We revealed structural development of the Pleistocene Sanukayama rhyolite lava of Kozushima Island, Japan. The good exposure, with about 130 m thick, provides valuable opportunity to understand the vertical structural variation. This exposure corresponds to the upper half of the lava. The paleomagnetic results show that the lava emplaced in subaerial condition at least in the exposed part. The vertical lithofacies are divided into the pumiceous (25-40 m thick), obsidian (40-60 m), spherulitic (30-50 m) layers from top to base. The pumiceous layer is characterized by massive foliated pumice. The foliation dips are gradually changed from gentle (10-30°) in lower part to steep (around 90°) in upper part. This shows the balloon-like morphology. The massive pumiceous layer would be generated from late stage diapiric inflation of the lava (Fink and Manley, 1987). The obsidian layer is composed of massive and welded-brecciated parts. The ductile-deformed light-colored veins, with a few mm thick, are frequently developed. In the microscopic observation, the veins are composed of broken crystals and obsidian clasts indicating fracturing of the lava followed by ductile deformation such as the RFH process (Tuffen et al., 2003). In this layer, extensive vesiculation and microlite development must have been prevented by higher load pressure and faster cooling, respectively. Consequently, they resulted in formation of the obsidian. The spherulitic layer is characterized by development of the ductile-deformed flow banding. The microscopic observation shows that the bands are formed by the spherulite trail. Furthermore, the microlites are aligned within the spherulites. In the heat-retained inner part of the lava, microlites would be developed around the healed fractures. The microlites acted as nucleation site of spherulite. In transition layer between obsidian and spherulitic layers (<10 m thick), the fragments of spherulitic rhyolite are entrained within the obsidian layer

  8. Irregular wall roughness in turbulent Taylor-Couette flow

    NASA Astrophysics Data System (ADS)

    Berghout, Pieter; Zhu, Xiaojue; Verzicco, Roberto; Lohse, Detlef; Stevens, Richard

    2017-11-01

    Many wall bounded flows in nature, engineering and transport are affected by surface roughness. Often, this has adverse effects, e.g. drag increase leading to higher energy costs. A major difficulty is the infinite number of roughness geometries, which makes it impossible to systematically investigate all possibilities. Here we present Direct Numerical Simulations (DNS) of turbulent Taylor-Couette flow. We focus on the transitionally rough regime, in which both viscous and pressure forces contribute to the total wall stress. We investigate the effect of the mean roughness height and the effective slope on the roughness function, ΔU+ . Also, we present simulations of varying Ta (Re) numbers for a constant mean roughness height (kmean+). Alongside, we show the behavior of the large scale structures (e.g. plume ejection, Taylor rolls) and flow structures in the vicinity of the wall.

  9. Lightcurve Analysis and Rotation Period Determination for Asteroids 1491 Balduinus and 2603 Taylor

    NASA Astrophysics Data System (ADS)

    Odden, Caroline E.; Cohen, Adam J.; Davis, Spencer; Eldracher, Emelie A.; Fitzgerald, Zachary T.; Jiang, Derek C.; Kozol, Eliana L.; Laurencin, Victoria L.; Meyer-Idzik, Benjamin D.; Pennington, Oliver; Philip, Reuben C.; Sanchez, Emily J.; Warren, Natalie J.; Klinglesmith, Daniel A.; Briggs, John W.

    2018-07-01

    Photometric observations of asteroids 1491 Balduinus and 2603 Taylor were made from 2017 December to 2018 February. 1491 Balduinus was found to have a rotational period 15.315 ± 0.003 h with amplitude 0.40 mag; 2603 Taylor was found to have rotational period 3.905 ± 0.001 h with amplitude 0.27 mag.

  10. Geochemistry of the Spor Mountain rhyolite, western Utah, as revealed by laser ablation ICP-MS, cathodoluminescence, and electron microprobe analysis

    NASA Astrophysics Data System (ADS)

    Dailey, S. R.; Christiansen, E. H.; Dorais, M.; Fernandez, D. P.

    2015-12-01

    The Miocene topaz rhyolite at Spor Mountain in western Utah hosts one of the largest beryllium deposits in the world and was responsible for producing 85% of the beryllium mined worldwide in 2010 (Boland, 2012). The Spor Mountain rhyolite is composed primarily of Ca-poor plagioclase (An8), sodic sanidine (Or40), Fe-rich biotite (Fe/(Fe+Mg)>0.95; Al 1.2-1.4 apfu), and Ti-poor quartz, along with several trace-element rich accessory phases including zircon, monazite, thorite, columbite, and allanite. Cathodoluminescence (CL) studies of quartz show oscillatory zoning, with 80% of the examined crystals displaying euhedral edges and slightly darker rims. CL images were used to guide laser ablation (LA) ICP-MS analysis of quartz, along with analyses of plagioclase, sanidine, biotite, and glass. Ti concentrations in quartz are 20±6 ppm; there is no quantifiable variation of Ti from core to rim within the diameter of the laser spot (53 microns). Temperatures, calculated using Ti in quartz (at 2 kb, aTiO2=0.34), vary between 529±10 C (Thomas et al., 2011), 669±13 C (Huang and Audetat, 2012), and 691±13 C (Wark and Watson, 2006). Two feldspar thermometry yield temperatures of 686±33 C (Elkins and Grove, 1990) and 670±41 C (Benisek et al., 2010). Zr saturation temperatures (Watson and Harrison, 1983) average 711±28 C. Analysis of the glass reveal the Spor Mountain rhyolite is greatly enriched in rare elements (i.e. Li, Be, F, Ga, Rb, Nb, Mo, Sn, and Ta) compared to average continental crust (Rudnick and Gao, 2003). Be in the glass can have as much as 100 ppm, nearly 50 times the concentration in continental crust. REE partition coefficients for sanidine are 2 to 3 times higher in the Spor Mountain rhyolite when compared to other silicic magmas (Nash and Crecraft, 1985; Mahood and Hildreth, 1983), although plagioclase tends to have lower partition coefficients; biotite has lower partition coefficients for LREE and higher partition coefficients for HREE. The patterns of

  11. 1. EXTERIOR OVERVIEW OF NORTH END OF RUSH CREEK POWERHOUSE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR OVERVIEW OF NORTH END OF RUSH CREEK POWERHOUSE RESIDENTIAL COMPLEX SHOWING BUILDING 108 AT PHOTO RIGHT AND BUILDING 105 AT PHOTO CENTER BEHIND SWITCHRACKS AND TREE. POWERHOUSE IS AT EXTREME PHOTO LEFT. VIEW TO WEST. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA

  12. Early Cretaceous MORB-type basalt and A-type rhyolite in northern Tibet: Evidence for ridge subduction in the Bangong-Nujiang Tethyan Ocean

    NASA Astrophysics Data System (ADS)

    Fan, Jian-Jun; Li, Cai; Sun, Zhen-Ming; Xu, Wei; Wang, Ming; Xie, Chao-Ming

    2018-04-01

    New zircon U-Pb ages, major- and trace-element data, and Hf isotopic compositions are presented for bimodal volcanic rocks of the Zhaga Formation (ZF) in the western-middle segment of the Bangong-Nujiang suture zone (BNSZ), northern Tibet. The genesis of these rocks is described, and implications for late-stage evolution of the Bangong-Nujiang Tethyan Ocean (BNTO) are considered. Detailed studies show that the ZF bimodal rocks, which occur as layers within a typical bathyal to abyssal flysch deposit, comprise MORB-type basalt that formed at a mid-ocean ridge, and low-K calc-alkaline A-type rhyolite derived from juvenile crust. The combination of MORB-type basalt, calc-alkaline A-type rhyolite, and bathyal to abyssal flysch deposits in the ZF leads us to propose that they formed as a result of ridge subduction. The A-type ZF rhyolites yield LA-ICP-MS zircon U-Pb ages of 118-112 Ma, indicating formation during the Early Cretaceous. Data from the present study, combined with regional geological data, indicate that the BNTO underwent conversion from ocean opening to ocean closure during the Late Jurassic-Early Cretaceous. The eastern segment of the BNTO closed during this period, while the western and western-middle segments were still at least partially open and active during the Early Cretaceous, accompanied by ridge subduction within the Bangong-Nujiang Tethyan Ocean.

  13. Frank Bursley Taylor - Forgotten Pioneer of Continental Drift.

    ERIC Educational Resources Information Center

    Black, George W., Jr.

    1979-01-01

    Frank B. Taylor was an American geologist who specialized in the glacial geology of the Great Lakes. This article discusses his work on the Continental Drift theory, which preceeded the work of Alfred Wegener by a year and a half. (MA)

  14. CURTIS TAYLOR, PRESIDENT OF LINC RESEARCH CORP.

    NASA Image and Video Library

    2016-04-27

    CURTIS O. TAYLOR, PRESIDENT OF LINC RESEARCH CORP, (L), AND JEFF LINDNER, CHIEF ENGINEER, POSE WITH HARDWARE FOR THEIR PATENTED TECHNOLOGY, FLUID STRUCTURE COUPLING, WHICH USES SIMPLE PHYSICS TO DAMPEN POTENTIALLY HARMFUL SHAKING IN STRUCTURES. INSTALLATION OF THE FLUID STRUCTURE COUPLING TECHNOLOGY IN A BUILDING WILL TAKE PLACE IN SUMMER OF 2016.

  15. 27 CFR 9.64 - Dry Creek Valley.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Dry Creek Valley. 9.64 Section 9.64 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.64 Dry Creek Valley. (a) Name. The name of the...

  16. 27 CFR 9.64 - Dry Creek Valley.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Dry Creek Valley. 9.64 Section 9.64 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.64 Dry Creek Valley. (a) Name. The name of the...

  17. 27 CFR 9.64 - Dry Creek Valley.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Dry Creek Valley. 9.64 Section 9.64 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.64 Dry Creek Valley. (a) Name. The name of the...

  18. 27 CFR 9.64 - Dry Creek Valley.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Dry Creek Valley. 9.64 Section 9.64 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.64 Dry Creek Valley. (a) Name. The name of the...

  19. 27 CFR 9.64 - Dry Creek Valley.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Dry Creek Valley. 9.64 Section 9.64 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.64 Dry Creek Valley. (a) Name. The name of the...

  20. Geological and 40Ar/39Ar age constraints on late-stage Deccan rhyolitic volcanism, inter-volcanic sedimentation, and the Panvel flexure from the Dongri area, Mumbai

    NASA Astrophysics Data System (ADS)

    Sheth, Hetu C.; Pande, Kanchan

    2014-04-01

    Post-K-Pg Boundary Deccan magmatism is well known from the Mumbai area in the Panvel flexure zone. Represented by the Salsette Subgroup, it shows characters atypical of much of the Deccan Traps, including rhyolite lavas and tuffs, mafic tuffs and breccias, spilitic pillow basalts, and "intertrappean" sedimentary or volcanosedimentary deposits, with mafic intrusions as well as trachyte intrusions containing basaltic enclaves. The intertrappean deposits have been interpreted as formed in shallow marine or lagoonal environments in small fault-bounded basins due to syn-volcanic subsidence. We report a previously unknown sedimentary deposit underlying the Dongri rhyolite flow from the upper part of the Salsette Subgroup, with a westerly tectonic dip due to the Panvel flexure. We have obtained concordant 40Ar/39Ar ages of 62.6 ± 0.6 Ma (2σ) and 62.9 ± 0.2 Ma (2σ) for samples taken from two separate outcrops of this rhyolite. The results are significant in showing that (i) Danian inter-volcanic sedimentary deposits formed throughout Mumbai, (ii) the rock units are consistent with the stratigraphy postulated earlier for Mumbai, (iii) shale fragments known in some Dongri tuffs were likely derived from the sedimentary deposit under the Dongri rhyolite, (iv) the total duration of extrusive and intrusive Deccan magmatism was at least 8-9 million years, and (v) Panvel flexure formed, or continued to form, after 63 Ma, possibly even 62 Ma, and could not have formed by 65-64 Ma as concluded in a recent study.

  1. The effect of crossflow on Taylor vortices: A model problem

    NASA Technical Reports Server (NTRS)

    Otto, S. R.; Bassom, Andrew P.

    1993-01-01

    A number of practically relevant problems involving the impulsive motion or the rapid rotation of bodies immersed in fluid are susceptible to vortex-like instability modes. Depending upon the configuration of any particular problem the stability properties of any high-wavenumber vortices can take on one of two distinct forms. One of these is akin to the structure of Gortler vortices in boundary layer flows while the other is similar to the situation for classical Taylor vortices. Both the Gortler and Taylor problems have been extensively studied when crossflow effects are excluded from the underlying base flows. Recently, studies were made concerning the influence of crossflow on Gortler modes and a linearized stability analysis is used to examine crossflow properties for the Taylor mode. This work allows us to identify the most unstable vortex as the crossflow component increases and it is shown how, like the Gortler case, only a very small crossflow component is required in order to completely stabilize the flow. Our investigation forms the basis for an extension to the nonlinear problem and is of potential applicability to a range of pertinent flows.

  2. Taylor bubbles at high viscosity ratios: experiments and numerical simulations

    NASA Astrophysics Data System (ADS)

    Hewakandamby, Buddhika; Hasan, Abbas; Azzopardi, Barry; Xie, Zhihua; Pain, Chris; Matar, Omar

    2015-11-01

    The Taylor bubble is a single long bubble which nearly fills the entire cross section of a liquid-filled circular tube, often occurring in gas-liquid slug flows in many industrial applications, particularly oil and gas production. The objective of this study is to investigate the fluid dynamics of three-dimensional Taylor bubble rising in highly viscous silicone oil in a vertical pipe. An adaptive unstructured mesh modelling framework is adopted here which can modify and adapt anisotropic unstructured meshes to better represent the underlying physics of bubble rising and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control volume and finite element formulation, a `volume of fluid'-type method for the interface-capturing based on a compressive control volume advection method, and a force-balanced algorithm for the surface tension implementation. Experimental results for the Taylor bubble shape and rise velocity are presented, together with numerical results for the dynamics of the bubbles. A comparison of the simulation predictions with experimental data available in the literature is also presented to demonstrate the capabilities of our numerical method. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  3. Conduit dynamics in transitional rhyolitic activity recorded by tuffisite vein textures from the 2008-2009 Chaitén eruption

    NASA Astrophysics Data System (ADS)

    Saubin, Elodie; Tuffen, Hugh; Gurioli, Lucia; Owen, Jacqueline; Castro, Jonathan; Berlo, Kim; McGowan, Ellen; Schipper, C. Ian; Wehbe, Katia

    2016-04-01

    Conduit processes govern the mechanisms of hazardous silicic eruptions, but our understanding of complex conduit behaviour is far from complete. Observations of recent Chilean rhyolite eruptions have revealed the importance of hybrid activity, involving simultaneous explosive and effusive emissions from a common vent[1]. Such behaviour hinges upon the ability of gas to decouple from magma in the shallow conduit. Tuffisite veins are increasingly suspected to be a key facilitator of outgassing, as they repeatedly provide a transient permeable escape route for volcanic gases. However, we have limited insights into the interactions between tuffisites and foams that appear critical to efficient outgassing[2], and into how heterogeneous conduit magma responds to pressure perturbations related to repeated disruption or slip of dense magma plugs. Here we provide a detailed characterization of an exceptionally large tuffisite vein within a rhyolitic obsidian bomb ejected during transitional explosive-effusive activity at volcán Chaitén, Chile in May 2008. Vein textures and chemistry provide a time-integrated record of the invasion of a dense upper conduit plug by deeper fragmented magma. Quantitative textural analysis reveals diverse vesiculation histories of varied juvenile clast types. Using vesicle size distributions, bubble number densities, zones of diffusive water depletion, and glass H2O concentrations, we propose a multi-step degassing/fragmentation history, spanning deep degassing to explosive bomb ejection. Rapid decompression events of ~3-4 MPa are associated with fragmentation of foam and dense magma at ~200-300 metres depth in the conduit, permitting vertical gas and pyroclast mobility over >100-200 metres. Permeable pathway occlusion in the dense conduit plug by pyroclast accumulation and sintering preceded ultimate bomb ejection, which triggered a final bubble nucleation event. Our results highlight how the vesiculation response of magma to decompression

  4. Return Spawning/Rearing Habitat to Anadromous/Resident Fish within the Fishing Creek to Legendary Bear Creek Analysis Area Watersheds; 2002-2003 Final Report.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Taylor, Jr., Emmit E.

    2004-03-01

    This project is a critical component of currently on-going watershed restoration effort in the Lochsa River Drainage, including the Fishing (Squaw) Creek to Legendary Bear (Papoose) Creek Watersheds Analysis Area. In addition, funding for this project allowed expansion of the project into Pete King Creek and Cabin Creek. The goal of this project is working towards the re-establishment of healthy self-sustaining populations of key fisheries species (spring Chinook salmon, steelhead, bull trout, and westslope cutthroat trout) through returning historic habitat in all life stages (spawning, rearing, migration, and over-wintering). This was accomplished by replacing fish barrier road crossing culverts withmore » structures that pass fish and accommodate site conditions.« less

  5. 75 FR 8036 - Monitor-Hot Creek Rangeland Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... DEPARTMENT OF AGRICULTURE Forest Service Monitor-Hot Creek Rangeland Project AGENCY: Forest... Rangeland Project area. The analysis will determine if a change in management direction for livestock grazing is needed to move existing resource conditions within the Monitor-Hot Creek Rangeland Project area...

  6. Rayleigh-Taylor mixing with time-dependent acceleration

    NASA Astrophysics Data System (ADS)

    Abarzhi, Snezhana

    2016-10-01

    We extend the momentum model to describe Rayleigh-Taylor (RT) mixing driven by a time-dependent acceleration. The acceleration is a power-law function of time, similarly to astrophysical and plasma fusion applications. In RT flow the dynamics of a fluid parcel is driven by a balance per unit mass of the rates of momentum gain and loss. We find analytical solutions in the cases of balanced and imbalanced gains and losses, and identify their dependence on the acceleration exponent. The existence is shown of two typical regimes of self-similar RT mixing-acceleration-driven Rayleigh-Taylor-type and dissipation-driven Richtymer-Meshkov-type with the latter being in general non-universal. Possible scenarios are proposed for transitions from the balanced dynamics to the imbalanced self-similar dynamics. Scaling and correlations properties of RT mixing are studied on the basis of dimensional analysis. Departures are outlined of RT dynamics with time-dependent acceleration from canonical cases of homogeneous turbulence as well as blast waves with first and second kind self-similarity. The work is supported by the US National Science Foundation.

  7. Singularities in water waves and Rayleigh-Taylor instability

    NASA Technical Reports Server (NTRS)

    Tanveer, S.

    1991-01-01

    Singularities in inviscid two-dimensional finite-amplitude water waves and inviscid Rayleigh-Taylor instability are discussed. For the deep water gravity waves of permanent form, through a combination of analytical and numerical methods, results describing the precise form, number, and location of singularities in the unphysical domain as the wave height is increased are presented. It is shown how the information on the singularity in the unphysical region has the same form as for deep water waves. However, associated with such a singularity is a series of image singularities at increasing distances from the physical plane with possibly different behavior. Furthermore, for the Rayleigh-Taylor problem of motion of fluid over a vacuum and for the unsteady water wave problem, integro-differential equations valid in the unphysical region are derived, and how these equations can give information on the nature of singularities for arbitrary initial conditions is shown.

  8. A mangrove creek restoration plan utilizing hydraulic modeling.

    PubMed

    Marois, Darryl E; Mitsch, William J

    2017-11-01

    Despite the valuable ecosystem services provided by mangrove ecosystems they remain threatened around the globe. Urban development has been a primary cause for mangrove destruction and deterioration in south Florida USA for the last several decades. As a result, the restoration of mangrove forests has become an important topic of research. Using field sampling and remote-sensing we assessed the past and present hydrologic conditions of a mangrove creek and its connected mangrove forest and brackish marsh systems located on the coast of Naples Bay in southwest Florida. We concluded that the hydrology of these connected systems had been significantly altered from its natural state due to urban development. We propose here a mangrove creek restoration plan that would extend the existing creek channel 1.1 km inland through the adjacent mangrove forest and up to an adjacent brackish marsh. We then tested the hydrologic implications using a hydraulic model of the mangrove creek calibrated with tidal data from Naples Bay and water levels measured within the creek. The calibrated model was then used to simulate the resulting hydrology of our proposed restoration plan. Simulation results showed that the proposed creek extension would restore a twice-daily flooding regime to a majority of the adjacent mangrove forest and that there would still be minimal tidal influence on the brackish marsh area, keeping its salinity at an acceptable level. This study demonstrates the utility of combining field data and hydraulic modeling to aid in the design of mangrove restoration plans.

  9. Clinopyroxene Diffusion Chronometry of the Scaup Lake Rhyolite, Yellowstone Caldera, WY

    NASA Astrophysics Data System (ADS)

    Brugman, K. K.; Till, C. B.; Bose, M.

    2016-12-01

    Eruption of the Scaup Lake flow (SCL) ended 220,000 years of dormancy and began the youngest sequence of eruptions at Yellowstone caldera [Christiansen et al., USGS, 2007]. Quantification of the time intervals between magmatic events and eruption recorded in SCL is critical to interpreting signs of unrest at modern-day Yellowstone. SCL rhyolite includes zoned phenocrysts and accessory phases that indicate multiple rejuvenation events occurred shortly before eruption; previous studies focused on feldspar and zircon crystal records [e.g. Bindeman et al., J.Pet, 2008; Till et al., Geology, 2015]. Here we exploit zoned clinopyroxene (cpx)—one of the earliest-crystalized minerals in SCL as indicated by petrographic relationships—as a diffusion dating tool and utilize elements with different diffusivities to more precisely resolve rejuvenation-eruption timescales. Using NanoSIMS concentration profiles with 300-900 nanometer spacing, we employ the slower-diffusing REE Ce as a proxy for the initial profile shape of faster-diffusing Fe to calculate diffusive timescales. The outermost resolvable zone boundary in SCL cpx yields a rejuvenation-eruption timescale of 166 ± 80 yrs (1 SD). In comparison, modeling relaxation of Fe from a step function initial condition at the same temperature (920°C) yields a less precise timescale of 488 +9000 -300 yrs. Examination of our results, in concert with observed petrographic relationships, indicates SCL cpx may record an older, separate rejuvenation event than those recorded in feldspar rims at < 10 months and 10-40 years prior to eruption [Till et al., Geology, 2015]. The difference in the youngest recorded event between feldspar and cpx may be due to different crystallization intervals for these phases and/or slower crystal growth rates for cpx relative to feldspar. Our diffusion modeling results reinforce that intracrystalline zoning timescales modeled using a step function initial condition should be considered maxima

  10. Recovery of a PCB-Contaminated Creek Fish Community

    EPA Science Inventory

    Polychlorinated Biphenyls (PCBs) from the Sangamo-Weston Superfund Site near Clemson, South Carolina, USA, were released into the Twelvemile Creek until the early 1990s. PCB concentrations in fish in this creek have remained elevated: levels in six target fish species are still a...

  11. Boundary effects and the onset of Taylor vortices

    NASA Astrophysics Data System (ADS)

    Rucklidge, A. M.; Champneys, A. R.

    2004-05-01

    It is well established that the onset of spatially periodic vortex states in the Taylor-Couette flow between rotating cylinders occurs at the value of Reynolds number predicted by local bifurcation theory. However, the symmetry breaking induced by the top and bottom plates means that the true situation should be a disconnected pitchfork. Indeed, experiments have shown that the fold on the disconnected branch can occur at more than double the Reynolds number of onset. This leads to an apparent contradiction: why should Taylor vortices set in so sharply at the Reynolds number predicted by the symmetric theory, given such large symmetry-breaking effects caused by the boundary conditions? This paper offers a generic explanation. The details are worked out using a Swift-Hohenberg pattern formation model that shares the same qualitative features as the Taylor-Couette flow. Onset occurs via a wall mode whose exponential tail penetrates further into the bulk of the domain as the driving parameter increases. In a large domain of length L, we show that the wall mode creates significant amplitude in the centre at parameter values that are O( L-2) away from the value of onset in the problem with ideal boundary conditions. We explain this as being due to a Hamiltonian Hopf bifurcation in space, which occurs at the same parameter value as the pitchfork bifurcation of the temporal dynamics. The disconnected anomalous branch remains O(1) away from the onset parameter since it does not arise as a bifurcation from the wall mode.

  12. THE VIOLATION OF THE TAYLOR HYPOTHESIS IN MEASUREMENTS OF SOLAR WIND TURBULENCE

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Klein, K. G.; Howes, G. G.; TenBarge, J. M.

    2014-08-01

    Motivated by the upcoming Solar Orbiter and Solar Probe Plus missions, qualitative and quantitative predictions are made for the effects of the violation of the Taylor hypothesis on the magnetic energy frequency spectrum measured in the near-Sun environment. The synthetic spacecraft data method is used to predict observational signatures of the violation for critically balanced Alfvénic turbulence or parallel fast/whistler turbulence. The violation of the Taylor hypothesis can occur in the slow flow regime, leading to a shift of the entire spectrum to higher frequencies, or in the dispersive regime, in which the dissipation range spectrum flattens at high frequencies.more » It is found that Alfvénic turbulence will not significantly violate the Taylor hypothesis, but whistler turbulence will. The flattening of the frequency spectrum is therefore a key observational signature for fast/whistler turbulence.« less

  13. Water Quality in Courtland Creek, East Oakland, California

    NASA Astrophysics Data System (ADS)

    Bracho, H.; Ahumada, A.; Hernandez, G.; Quintero, D.; Ramirez, J.; Ramirez, L.; Pham, T.; Holt, J.; Johnson, A.; Rubio, E.; Ponce, X.; Medina, S.; Limon, S.

    2013-12-01

    Courtland Creek is a tributary of the larger East Creek system that runs southeast from the Oakland Hills down to the San Leandro Bay in Oakland, California. In an effort to assess the overall health of Courtland Creek our team conducted a water quality research study. Stream water samples were collected from 4 sites between MacArthur Avenue (describe geographically as not all readers are familiar with Oakland geography) and Thompson Avenue (describe geographically as not all readers are familiar with Oakland geography) at accessible sections of this largely culverted stream. Dissolved oxygen, ammonia, nitrite, nitrate, phosphate, and chlorine concentrations in were measured using wet chemistry procedures. Analysis of collected samples indicates that dissolved oxygen levels in the stream are sufficient for invertebrates, ranging from 5 and 9 parts per million (ppm). Nitrate levels were significantly high, with concentrations ranging from 15 and 40 ppm. Other chemical species associated with waste products--ammonia, nitrite, and phosphate--also were present, but at low concentrations. Small amounts of chlorine also were found in waters of the creek system. The presence of high concentrations of nitrate, together with chlorine, suggests that untreated sewage may be leaking into Courtland Creek at an unidentified location.

  14. Scotch Creek Wildlife Area 2007-2008 Annual Report.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Olson, Jim

    The Scotch Creek Wildlife Area is a complex of 6 separate management units located in Okanogan County in North-central Washington State. The project is located within the Columbia Cascade Province (Okanogan sub-basin) and partially addresses adverse impacts caused by the construction of Chief Joseph and Grand Coulee hydroelectric dams. With the acquisition of the Eder unit in 2007, the total size of the wildlife area is now 19,860 acres. The Scotch Creek Wildlife Area was approved as a wildlife mitigation project in 1996 and habitat enhancement efforts to meet mitigation objectives have been underway since the spring of 1997 onmore » Scotch Creek. Continuing efforts to monitor the threatened Sharp-tailed grouse population on the Scotch Creek unit are encouraging. The past two spring seasons were unseasonably cold and wet, a dangerous time for the young of the year. This past spring, Scotch Creek had a cold snap with snow on June 10th, a critical period for young chicks just hatched. Still, adult numbers on the leks have remained stable the past two years. Maintenance of BPA funded enhancements is necessary to protect and enhance shrub-steppe and to recover and sustain populations of Sharp-tailed grouse and other obligate species.« less

  15. A dolichopodid hotspot: Montana's Milligan Creek Canyon

    Treesearch

    Justin B. Runyon

    2016-01-01

    In southwest Montana, near the town of Three Forks, Milligan Creek cuts a small and seemingly mundane notch through dry limestone hills. Milligan Creek is unassuming and small enough to be effortlessly stepped over in most places. In fact, it flows underground for much of its 4-5 mile journey to the Jefferson River. Incredibly, forty-nine species of long-legged flies (...

  16. Final Environmental Assessment, Horse Creek Bridge Replacement

    DTIC Science & Technology

    2010-10-01

    Final Environmental Assessment Horse Creek Bridge Replacement 78th Civil Engineer Group...Final Environmental Assessment Horse Creek Bridge Replacement 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 FINDING OF NO SIGNIFICANT IMPACT (FONSI)/ FINDING OF NO PRACTICABLE ALTERNATIVE (FONP A) HORSE

  17. Application of Taylor's series to trajectory propagation

    NASA Technical Reports Server (NTRS)

    Stanford, R. H.; Berryman, K. W.; Breckheimer, P. J.

    1986-01-01

    This paper describes the propagation of trajectories by the application of the preprocessor ATOMCC which uses Taylor's series to solve initial value problems in ordinary differential equations. Comparison of the results obtained with those from other methods are presented. The current studies indicate that the ATOMCC preprocessor is an easy, yet fast and accurate method for generating trajectories.

  18. Taylor Proposes Five-Year Child-Care Program.

    ERIC Educational Resources Information Center

    Taylor, Glen

    Senator Glen Taylor of Minnesota proposed a five-year child-care program for the purposes of encouraging employer-sponsored child care and increasing by 53,000 the number of children in low-income families who were covered. This report lists central features of the program, which include: (1) tax incentives which employers can use when they build…

  19. Reliability, validity and description of timed performance of the Jebsen-Taylor Test in patients with muscular dystrophies.

    PubMed

    Artilheiro, Mariana Cunha; Fávero, Francis Meire; Caromano, Fátima Aparecida; Oliveira, Acary de Souza Bulle; Carvas, Nelson; Voos, Mariana Callil; Sá, Cristina Dos Santos Cardoso de

    2017-12-08

    The Jebsen-Taylor Test evaluates upper limb function by measuring timed performance on everyday activities. The test is used to assess and monitor the progression of patients with Parkinson disease, cerebral palsy, stroke and brain injury. To analyze the reliability, internal consistency and validity of the Jebsen-Taylor Test in people with Muscular Dystrophy and to describe and classify upper limb timed performance of people with Muscular Dystrophy. Fifty patients with Muscular Dystrophy were assessed. Non-dominant and dominant upper limb performances on the Jebsen-Taylor Test were filmed. Two raters evaluated timed performance for inter-rater reliability analysis. Test-retest reliability was investigated by using intraclass correlation coefficients. Internal consistency was assessed using the Cronbach alpha. Construct validity was conducted by comparing the Jebsen-Taylor Test with the Performance of Upper Limb. The internal consistency of Jebsen-Taylor Test was good (Cronbach's α=0.98). A very high inter-rater reliability (0.903-0.999), except for writing with an Intraclass correlation coefficient of 0.772-1.000. Strong correlations between the Jebsen-Taylor Test and the Performance of Upper Limb Module were found (rho=-0.712). The Jebsen-Taylor Test is a reliable and valid measure of timed performance for people with Muscular Dystrophy. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

  20. Geohydrology of the stratified-drift aquifer system in the lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York

    USGS Publications Warehouse

    Miller, Todd S.; Karig, Daniel E.

    2010-01-01

    In 2002, the U.S. Geological Survey, in cooperation with the Tompkins County Planning Department began a series of studies of the stratified-drift aquifers in Tompkins County to provide geohydrologic data for planners to develop a strategy to manage and protect their water resources. This aquifer study in lower Sixmile Creek and Willseyville Creek trough is the second in a series of aquifer studies in Tompkins County. The study area is within the northern area of the Appalachian Plateau and extends about 9 miles from the boundary between Tompkins County and Tioga County in the south to just south of the City of Ithaca in the north. In lower Sixmile Creek and Willseyville Creek trough, confined sand and gravel aquifers comprise the major water-bearing units while less extensive unconfined units form minor aquifers. About 600 people who live in lower Sixmile Creek and Willseyville Creek trough rely on groundwater from the stratified-drift aquifer system. In addition, water is used by non-permanent residents such as staff at commercial facilities. The estimated total groundwater withdrawn for domestic use is about 45,000 gallons per day (gal/d) or 0.07 cubic foot per second (ft3/s) based on an average water use of 75 gal/d per person for self-supplied water systems in New York. Scouring of bedrock in the preglacial lower Sixmile Creek and Willseyville Creek valleys by glaciers and subglacial meltwaters truncated hillside spurs, formed U-shaped, transverse valley profiles, smoothed valley walls, and deepened the valleys by as much as 300 feet (ft), forming a continuous trough. The unconsolidated deposits in the study area consist mostly of glacial drift, both unstratified drift (till) and stratified drift (laminated lake, deltaic, and glaciofluvial sediments), as well as some post-glacial stratified sediments (lake-bottom sediments that were deposited in reservoirs, peat and muck that were deposited in wetlands, and alluvium deposited by streams). Multiple advances and

  1. Tweedie convergence: a mathematical basis for Taylor's power law, 1/f noise, and multifractality.

    PubMed

    Kendal, Wayne S; Jørgensen, Bent

    2011-12-01

    Plants and animals of a given species tend to cluster within their habitats in accordance with a power function between their mean density and the variance. This relationship, Taylor's power law, has been variously explained by ecologists in terms of animal behavior, interspecies interactions, demographic effects, etc., all without consensus. Taylor's law also manifests within a wide range of other biological and physical processes, sometimes being referred to as fluctuation scaling and attributed to effects of the second law of thermodynamics. 1/f noise refers to power spectra that have an approximately inverse dependence on frequency. Like Taylor's law these spectra manifest from a wide range of biological and physical processes, without general agreement as to cause. One contemporary paradigm for 1/f noise has been based on the physics of self-organized criticality. We show here that Taylor's law (when derived from sequential data using the method of expanding bins) implies 1/f noise, and that both phenomena can be explained by a central limit-like effect that establishes the class of Tweedie exponential dispersion models as foci for this convergence. These Tweedie models are probabilistic models characterized by closure under additive and reproductive convolution as well as under scale transformation, and consequently manifest a variance to mean power function. We provide examples of Taylor's law, 1/f noise, and multifractality within the eigenvalue deviations of the Gaussian unitary and orthogonal ensembles, and show that these deviations conform to the Tweedie compound Poisson distribution. The Tweedie convergence theorem provides a unified mathematical explanation for the origin of Taylor's law and 1/f noise applicable to a wide range of biological, physical, and mathematical processes, as well as to multifractality.

  2. Expanding Geophysical and Geochemical Investigation of Causes of Extraordinary Unrest at the Laguna del Maule (Rhyolitic) Volcanic Field, Southern Andes, Chile

    NASA Astrophysics Data System (ADS)

    Singer, B. S.

    2014-12-01

    The Laguna del Maule Volcanic Field, Chile, includes an unusually large and recent concentration of silicic eruptions. Since 2007 the crust here has been inflating at an astonishing rate of 25 cm/yr. Findings thus far lead to the hypothesis that the silicic vents have tapped an extensive layer of crystal-poor, rhyolitic melt that began to form atop a magmatic mush zone that was established by ~20 ka with a renewed phase of rhyolite eruptions during the Holocene. Modeling of surface deformation, magnetotelluric data, and gravity changes suggest that magma is currently intruding at a depth of ~5 km. Swarms of volcano-tectonic and long period earthquakes, mostly of M < 2, have occurred beneath the most recent rhyolite coulees on the southwestern and southern margins of the 20 km diameter ring of silicic vents. With support from the US NSF and the Chilean government (SERNAGEOMIN and OVDAS) we are seizing the unique opportunity to investigate, over the next 5 years, the dynamics of this large rhyolitic system while magma migration, reservoir growth, and crustal deformation are actively underway. This collaboration involves scientists and students at: University of Wisconsin-Madison, Georgia Tech, Cornell, University of Alberta, Simon Fraser University, University of Chile-Santiago, CONICET/University of San Juan-Argentina, Nanyang Technological University-Singapore, SERNAGEOMIN, OVDAS, USGS, and SEGEMAR-Argentina. Team members will be introduced in this presentation. Our approach includes augmenting the OVDAS array of 6 permanent seisic stations with 40 additional instruments to conduct tomographic, receiver function and ambient noise studies. We continue to collect 4-D gravity data from 37 stations. Surface deformation is monitored via cGPS at 5 permanent receivers and InSAR data. A magnetotelluric survey across the Andes at 36o S is planned. Geochemical studies include mineral zoning and U-Th disequilibrium of zircons to constrain the timing of magma intrusion and

  3. Water resources of Bannock Creek basin, southeastern Idaho

    USGS Publications Warehouse

    Spinazola, Joseph M.; Higgs, B.D.

    1997-01-01

    The potential for development of water resources in the Bannock Creek Basin is limited by water supply. Bannock Creek Basin covers 475 square miles in southeastern Idaho. Shoshone-Bannock tribal lands on the Fort Hall Indian Reservation occupy the northern part of the basin; the remainder of the basin is privately owned. Only a small amount of information on the hydrologic and water-quality characteristics of Bannock Creek Basin is available, and two previous estimates of water yield from the basin ranged widely from 45,000 to 132,500 acre-feet per year. The Shoshone-Bannock Tribes need an accurate determination of water yield and baseline water-quality characteristics to plan and implement a sustainable level of water use in the basin. Geologic setting, quantities of precipitation, evapotranspiration, surface-water runoff, recharge, and ground-water underflow were used to determine water yield in the basin. Water yield is the annual amount of surface and ground water available in excess of evapotranspiration by crops and native vegetation. Water yield from Bannock Creek Basin was affected by completion of irrigation projects in 1964. Average 1965-89 water yield from five subbasins in Bannock Creek Basin determined from water budgets was 60,600 acre-feet per year. Water yield from the Fort Hall Indian Reservation part of Bannock Creek Basin was estimated to be 37,700 acre-feet per year. Water from wells, springs, and streams is a calcium bicarbonate type. Concentrations of dissolved nitrite plus nitrate as nitrogen and fluoride were less than Maximum Contaminant Levels for public drinking-water supplies established by the U.S. Environmental Protection Agency. Large concentrations of chloride and nitrogen in water from several wells, springs, and streams likely are due to waste from septic tanks or stock animals. Estimated suspended-sediment load near the mouth of Bannock Creek was 13,300 tons from December 1988 through July 1989. Suspended-sediment discharge was

  4. Stability of compressible Taylor-Couette flow

    NASA Technical Reports Server (NTRS)

    Kao, Kai-Hsiung; Chow, Chuen-Yen

    1991-01-01

    Compressible stability equations are solved using the spectral collocation method in an attempt to study the effects of temperature difference and compressibility on the stability of Taylor-Couette flow. It is found that the Chebyshev collocation spectral method yields highly accurate results using fewer grid points for solving stability problems. Comparisons are made between the result obtained by assuming small Mach number with a uniform temperature distribution and that based on fully incompressible analysis.

  5. 33 CFR 207.185 - Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation. 207.185 Section 207.185 Navigation and... § 207.185 Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation...

  6. 33 CFR 207.185 - Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation. 207.185 Section 207.185 Navigation and... § 207.185 Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation...

  7. Short-time Lyapunov exponent analysis and the transition to chaos in Taylor-Couette flow

    NASA Technical Reports Server (NTRS)

    Vastano, John A.; Moser, Robert D.

    1991-01-01

    The physical mechanism driving the weakly chaotic Taylor-Couette flow is investigated using the short-time Liapunov exponent analysis. In this procedure, the transition from quasi-periodicity to chaos is studied using direct numerical 3D simulations of axially periodic Taylor-Couette flow, and a partial Liapunov exponent spectrum for the flow is computed by simultaneously advancing the full solution and a set of perturbations. It is shown that the short-time Liapunov exponent analysis yields more information on the exponents and dimension than that obtained from the common Liapunov exponent calculations. Results show that the chaotic state studied here is caused by a Kelvin-Helmholtz-type instability of the outflow boundary jet of Taylor vortices.

  8. Insights into Near-Surface Structural Control of Hydrothermal Fluid Movement at Rabbit Creek Thermal Area, Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Carr, B.; Elliot, M.; Sims, K. W. W.

    2017-12-01

    Recent geophysical imaging efforts at Yellowstone National Park have generated questions about the geologic controls of hydrothermal fluid movement within the parks thermal areas. Currently, faults and lava flow contacts are assumed to be the primary permeability pathways for deeper fluid migration to the surface. Although intuition dictates that these structures are responsible, few studies have definitively shown that this is true. Earlier geophysical imaging efforts of phase separation in Norris Geyser Basin have shown strong evidence for fractures and faulting conducting hydrothermal waters. However, no geologically mapped faults are at the surface to confirm these interpretations. Therefore, during the summer of 2017, UW surface geophysical data acquisition focused on understanding the geologic controls for a thermal area within the well-mapped Rabbit Creek Fault Zone (RCFZ). The RCFZ strikes N-S along the eastern edge of Midway Geyser Basin (i.e. the western edge of the Mallard Lake Dome) about 2.8 Km SE of Grand Prismatic spring. The section of the fault zone within the Rabbit Creek thermal area is exposed on the eastern valley wall and dips steeply to the west. Regardless at our site, this puts the two of the plateau rhyolites (i.e. the Biscuit Basin Flow and Mallard Lake flow) next to each other ( 100 m apart) with a small amount of overlying alluvial, glacial and hydrothermal deposits covering the actual fault trace. Interestingly, at least two mapped reverse faults from the Mallard Lake Dome trend NW-SE into the site and are interpreted to intersect to the RCFZ. At RCFZ, DC resistivity and seismic refraction profiling combined with Self-Potential, Magnetics, and Transient Electromagnetic soundings were acquired to provide images and in situ geophysical properties. These data highlight the variable fracturing and surface expressions of the hydrothermal fluids associated with the RCFZ and the NW trending fault zone associated with the Mallard Lake Dome

  9. Valuing water quality in urban watersheds: A comparative analysis of Johnson Creek, Oregon, and Burnt Bridge Creek, Washington

    NASA Astrophysics Data System (ADS)

    Netusil, Noelwah R.; Kincaid, Michael; Chang, Heejun

    2014-05-01

    This study uses the hedonic price method to investigate the effect of five water quality parameters on the sale price of single-family residential properties in two urbanized watersheds in the Portland, Oregon-Vancouver, Washington metropolitan area. Water quality parameters include E. coli or fecal coliform, which can affect human health, decrease water clarity and generate foul odors; pH, dissolved oxygen, and stream temperature, which can impact fish and wildlife populations; and total suspended solids, which can affect water clarity, aquatic life, and aesthetics. Properties within ¼ mile, ½, mile, one mile, or more than one mile from Johnson Creek are estimated to experience an increase in sale price of 13.71%, 7.05%, 8.18%, and 3.12%, respectively, from a one mg/L increase in dissolved oxygen levels during the dry season (May-October). Estimates for a 100 count per 100 mL increase in E. coli during the dry season are -2.81% for properties within ¼ mile of Johnson Creek, -0.86% (½ mile), -1.19% (one mile), and -0.71% (greater than one mile). Results for properties in Burnt Bridge Creek include a significantly positive effect for a one mg/L increase in dissolved oxygen levels during the dry season for properties within ½ mile (4.49%), one mile (2.95%), or greater than one mile from the creek (3.17%). Results for other water quality parameters in Burnt Bridge Creek are generally consistent with a priori expectations. Restoration efforts underway in both study areas might be cost justified based on their estimated effect on property sale prices.

  10. Taylorism, Tylerism, and Performance Indicators: Defending the Indefensible?

    ERIC Educational Resources Information Center

    Helsby, Gill; Saunders, Murray

    1993-01-01

    Explores the antecedents to the growing interest in the use of educational performance indicators. Discusses this issue in relation to the work of economist F. W. Taylor and evaluator Ralph Tyler. Describes a five-year project that demonstrates the promise of teacher-developed performance indicators. (CFR)

  11. 33 CFR 117.115 - Three Mile Creek.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Three Mile Creek. 117.115 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Alabama § 117.115 Three Mile Creek. (a) The draw of the US43 bridge, mile 1.0 at Mobile, need not be opened from 7 a.m. to 9 a.m. and from 4:30 p.m. to 6...

  12. 33 CFR 117.115 - Three Mile Creek.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Three Mile Creek. 117.115 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Alabama § 117.115 Three Mile Creek. (a) The draw of the US43 bridge, mile 1.0 at Mobile, need not be opened from 7 a.m. to 9 a.m. and from 4:30 p.m. to 6...

  13. 33 CFR 117.115 - Three Mile Creek.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Three Mile Creek. 117.115 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Alabama § 117.115 Three Mile Creek. (a) The draw of the US43 bridge, mile 1.0 at Mobile, need not be opened from 7 a.m. to 9 a.m. and from 4:30 p.m. to 6...

  14. 33 CFR 117.115 - Three Mile Creek.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Three Mile Creek. 117.115 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Alabama § 117.115 Three Mile Creek. (a) The draw of the US43 bridge, mile 1.0 at Mobile, need not be opened from 7 a.m. to 9 a.m. and from 4:30 p.m. to 6...

  15. 33 CFR 117.115 - Three Mile Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Three Mile Creek. 117.115 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Alabama § 117.115 Three Mile Creek. (a) The draw of the US43 bridge, mile 1.0 at Mobile, need not be opened from 7 a.m. to 9 a.m. and from 4:30 p.m. to 6...

  16. AmeriFlux US-OWC Old Woman Creek

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bohrer, Gil

    This is the AmeriFlux version of the carbon flux data for the site US-OWC Old Woman Creek. Site Description - Old Woman Creek is a natural freshwater estuary connected to Lake Erie in northern Ohio. It is one of few natuaral estuary systems left in Ohio. The site is permanently flooded and contains a mixture of wetland vegetation, open water, and mud flats.

  17. Surface-water quality of coal-mine lands in Raccoon Creek Basin, Ohio

    USGS Publications Warehouse

    Wilson, K.S.

    1985-01-01

    The Ohio Department of Natural Resources, Division of Reclamation, plans to reclaim abandoned surface mines in the Raccoon Creek watershed in southern Ohio. Historic water-quality data collected between 1975 and 1983 were complied and analyzed in terms of eight selected mine-drainage characteristics to develop a data base for individual subbasin reclamation projects. Areas of mine drainage affecting Raccoon Creek basin, the study Sandy Run basin, the Hewett Fork basin, and the Little raccoon Creek basin. Surface-water-quality samples were collected from a 41-site network from November 1 through November 3, 1983, Results of the sampling reaffirmed that the major sources of mine drainage to Raccoon Creek are in the Little Raccoon Creek basin, and the Hewett Fork basin. However, water quality at the mouth of Sandy Run indicated that it is not a source of mine drainage to Raccoon Creek. Buffer Run, Goose Run, an unnamed tributary to Little Raccoon Creek, Mulga Run, and Sugar Run were the main sources of mine drainage sampled in the Little Raccoon Creek basin. All sites sampled in the East Branch Raccoon Creek basin were affected by mine drainage. This information was used to prepare a work plan for additional data collection before, during, and after reclamation. The data will be used to define the effectiveness of reclamation effects in the basin.

  18. Taylor Series Trajectory Calculations Including Oblateness Effects and Variable Atmospheric Density

    NASA Technical Reports Server (NTRS)

    Scott, James R.

    2011-01-01

    Taylor series integration is implemented in NASA Glenn's Spacecraft N-body Analysis Program, and compared head-to-head with the code's existing 8th- order Runge-Kutta Fehlberg time integration scheme. This paper focuses on trajectory problems that include oblateness and/or variable atmospheric density. Taylor series is shown to be significantly faster and more accurate for oblateness problems up through a 4x4 field, with speedups ranging from a factor of 2 to 13. For problems with variable atmospheric density, speedups average 24 for atmospheric density alone, and average 1.6 to 8.2 when density and oblateness are combined.

  19. Synchrotron radiation microtomography of Taylor bubbles in capillary two-phase flow

    NASA Astrophysics Data System (ADS)

    Boden, Stephan; dos Santos Rolo, Tomy; Baumbach, Tilo; Hampel, Uwe

    2014-07-01

    We report on a study to measure the three-dimensional shape of Taylor bubbles in capillaries using synchrotron radiation in conjunction with ultrafast radiographic imaging. Moving Taylor bubbles in 2-mm round and square capillaries were radiographically scanned with an ultrahigh frame rate of up to 36,000 fps and 5.6-µm pixel separation. Consecutive images were properly processed to yield 2D transmission radiographs of high contrast-to-noise ratio. Application of 3D tomographic image reconstruction disclosed the 3D bubble shape. The results provide a reference data base for development of sophisticated interface resolving CFD computations.

  20. 75 FR 68780 - Cedar Creek Wind Energy, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-09

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. RC11-1-000] Cedar Creek Wind Energy, LLC; Notice of Filing November 2, 2010. Take notice that on October 27, 2010, Cedar Creek Wind Energy, LLC (Cedar Creek) filed an appeal with the Federal Energy Regulatory Commission (Commission) of...

  1. San Mateo Creek Basin

    EPA Pesticide Factsheets

    The San Mateo Creek Basin comprises approximately 321 square miles within the Rio San Jose drainage basin in McKinley and Cibola counties, New Mexico. This basin is located within the Grants Mining District (GMD).

  2. Partridge Creek Diversion Project

    EPA Pesticide Factsheets

    Goal: prevent mercury contamination by keeping the creek from flowing through a mine pit. The project improved brook trout habitat, green infrastructure, the local economy, and decreased human health risks. Includes before-and-after photos.

  3. Genesis of late Early Cretaceous high-silica rhyolites in eastern Zhejiang Province, southeast China: A crystal mush origin with mantle input

    NASA Astrophysics Data System (ADS)

    Zhang, Ji-Heng; Yang, Jin-Hui; Chen, Jing-Yuan; Wu, Fu-Yuan; Wilde, Simon A.

    2018-01-01

    Voluminous Mesozoic felsic volcanic rocks and granites in southeastern China provide a unique opportunity for studying the role of crustal magmatism in the evolution and modification of the crust in the eastern Cathaysia Block. The high-silica rhyolites of the upper volcanic sequence in eastern Zhejiang Province were investigated, focusing on their genesis and their relationship with contemporaneous granites. Rhyolites in the Tiantai, Yongkang and Liucheng basins were dated as late Early Cretaceous (from 111 Ma to 106 Ma in age). These rocks contain a large proportion of inherited zircons of ca. 130 Ma, corresponding to the age of the lower volcanic sequence in the area. However, the zircons of different ages have similar ranges of oxygen and Hf isotopes, implying similarities in the magmas from which they were generated. The rhyolites of the upper sequence also resemble those of the lower sequence in terms of their geochemistry. It is concluded that the former were derived by reworking of magma mush formed during the earlier magmatic episode via fractionation of feldspars and accessory minerals, e.g., zircon. Fractionation took place within the magma crystal mush by extraction of interstitial melts and accumulation of residual mineral phases, aided by the emplacement of contemporaneous basaltic magmas at the base of the crust. Overall, the geochemical features of the volcanic rocks in southeastern China indicate that episodic magmatism and reworking of crystal mush were essential mechanisms that drove the evolution of the igneous rocks and the hence crustal architecture in this area.

  4. Residence, resorption and recycling of zircons in Devils Kitchen rhyolite, Coso Volcanic Field, California

    USGS Publications Warehouse

    Miller, J.S.; Wooden, J.L.

    2004-01-01

    Zircons from the Devils Kitchen rhyolite in the Pleistocene Coso Volcanic field, California have been analyzed by in situ Pb/U ion microprobe (SHRIMP-RG) and by detailed cathodoluminescence imaging. The zircons yield common-Pb-corrected and disequilibrium-corrected 206Pb/238U ages that predate a previously reported K-Ar sanidine age by up to 200 kyr, and the range of ages exhibited by the zircons is also approximately 200 kyr. Cathodoluminescence imaging indicates that zircons formed in contrasting environments. Most zircons are euhedral, and a majority of the zircons are weakly zoned, but many also have anhedral, embayed cores, with euhedral overgrowths and multiple internal surfaces that are truncated by later crystal zones. Concentrations of U and Th vary by two orders of magnitude within the zircon population, and by 10-20 times between zones within some zircon crystals, indicating that zircons were transferred between contrasting chemical environments. A zircon saturation temperature of ???750??C overlaps within error a previously reported phenocryst equilibration temperature of 740 ?? 25??C. Textures in zircons indicative of repeated dissolution and subsequent regrowth are probably caused by punctuated heating by mafic magma input into rhyolite. The overall span of ages and large variation in U and Th concentrations, combined with calculated zircon saturation temperatures and resorption times, are most compatible with crystallization in magma bodies that were emplaced piecemeal in the crust at Coso over 200 kyr prior to eruption, and that were periodically rejuvenated or melted by subsequent basaltic injections. ?? Oxford University Press 2004; all rights reserved.

  5. Fast-growing willow shrub named `Fish Creek`

    DOEpatents

    Abrahamson, Lawrence P.; Kopp, Richard F.; Smart, Lawrence B.; Volk, Timothy A.

    2007-05-08

    A distinct male cultivar of Salix purpurea named `Fish Creek`, characterized by rapid stem growth producing greater than 30% more woody biomass than either of its parents (`94001` and `94006`) and 20% more biomass than a current production cultivar (`SV1`). `Fish Creek` can be planted from dormant stem cuttings, produces multiple stems after coppice, and the stem biomass can be harvested when the plant is dormant. In the spring following harvest, the plant will re-sprout very vigorously, producing new stems that can be harvested after two to four years of growth. This harvest cycle can be repeated several times. The stem biomass can be chipped and burned as a source of renewable energy, generating heat and/or electricity. `Fish Creek` displays a low incidence of rust disease or damage by beetles or sawflies.

  6. The partitioning behavior of silver in a vapor brine rhyolite melt assemblage

    NASA Astrophysics Data System (ADS)

    Simon, Adam C.; Pettke, Thomas; Candela, Philip A.; Piccoli, Philip M.

    2008-03-01

    The partitioning of silver in a sulfur-free rhyolite melt-vapor-brine assemblage has been quantified at 800 °C, pressures of 100 and 140 MPa and f≈NNO (nickel-nickel oxide). Silver solubility (±2 σ) in rhyolite increases 5-fold from 105 ± 21 to 675 ± 98 μg/g as pressure increases from 100 to 140 MPa. Nernst-type partition coefficients (DAgi,j±2σ) describing the mass transfer of silver at 100 MPa between vapor and melt, brine and melt and vapor and brine are 32 ± 30, 1151 ± 238 and 0.026 ± 0.004, respectively. At 140 MPa, values for DAgi,j(±2σ) for vapor and melt, brine and melt, and vapor and brine are 32 ± 10, 413 ± 172 and 0.06 ± 0.03, respectively. Apparent equilibrium constant values (±2 σ) describing the exchange of silver and sodium between vapor and melt, KAg,Nav/m, at 100 and 140 MPa are 105 ± 68 and 14 ± 6. The average values (±2 σ) for silver and sodium exchange between brine and melt, KAg,Nab/m, at 100 and 140 MPa are 313 ± 288 and 65 ± 12. These data indicate that the mass transfer of silver from rhyolite melt to an exsolved volatile phase(s) is enhanced at 100 MPa relative to 140 MPa, suggesting that decompression increases the silver ore-generative potential of an evolving silicate magma. Model calculations using the new data suggest that the evolution of low-density, aqueous fluid (i.e., vapor) may be responsible for the the silver tonnage of many porphyry-type and perhaps epithermal-type ore deposits. For example, Halter et al. (Halter W. E., Pettke T. and Heinrich C. A. (2002) The origin of Cu/Au ratios in porphyry-type ore deposits. Science296, 1842-1844) used detailed silicate and sulfide melt inclusion and vapor and brine fluid inclusions analyses to estimate a melt volume on the order of 15 km 3 to satisfy the copper budget at the Bajo de la Alumbrera copper-, gold-, silver-ore deposit. Using their melt volume estimate with the data presented here, model calculations for a 15-km 3 felsic melt, saturated with pyrrhotite

  7. Rock Creek and Potomac Parkway / Waterside Drive Sycamore and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Rock Creek and Potomac Parkway / Waterside Drive Sycamore and White Ash Trees, Rock Creek and Potomac Parkway, median between northbound and southbound lanes near the Waterside Drive exit and entrance ramps., Washington, District of Columbia, DC

  8. Hydrology of Bishop Creek, California: An Isotopic Analysis

    Treesearch

    Michael L. Space; John W. Hess; Stanley D. Smith

    1989-01-01

    Five power generation plants along an eleven kilometer stretch divert Bishop Creek water for hydro-electric power. Stream diversion may be adversely affecting the riparian vegetation. Stable isotopic analysis is employed to determine surface water/ground-water interactions along the creek. surface water originates primarily from three headwater lakes. Discharge into...

  9. Solving ODE Initial Value Problems With Implicit Taylor Series Methods

    NASA Technical Reports Server (NTRS)

    Scott, James R.

    2000-01-01

    In this paper we introduce a new class of numerical methods for integrating ODE initial value problems. Specifically, we propose an extension of the Taylor series method which significantly improves its accuracy and stability while also increasing its range of applicability. To advance the solution from t (sub n) to t (sub n+1), we expand a series about the intermediate point t (sub n+mu):=t (sub n) + mu h, where h is the stepsize and mu is an arbitrary parameter called an expansion coefficient. We show that, in general, a Taylor series of degree k has exactly k expansion coefficients which raise its order of accuracy. The accuracy is raised by one order if k is odd, and by two orders if k is even. In addition, if k is three or greater, local extrapolation can be used to raise the accuracy two additional orders. We also examine stability for the problem y'= lambda y, Re (lambda) less than 0, and identify several A-stable schemes. Numerical results are presented for both fixed and variable stepsizes. It is shown that implicit Taylor series methods provide an effective integration tool for most problems, including stiff systems and ODE's with a singular point.

  10. Rhyolitic tephra record of the Gona region, southern Afar Rift, Ethiopia: Characteristics correlation and chronology

    NASA Astrophysics Data System (ADS)

    Dunbar, N. W.; Brown, F. H.; Levin, N. E.; McIntosh, W. C.; Rogers, M.; Semaw, S.; Simpson, S. W.; Stinchcomb, G. E.

    2016-12-01

    The Gona region, on the western flank of the southern Afar Rift, in Ethiopia, contains a rich and complex tephra record that provides insight into structural evolution of the region and chronological controls on the local record of human evolution. Despite lack of source volcanoes in the Gona region, thick (up to 80 cm), fine-grained (20-500 µm), fresh, pure, glassy distal tephra layers, which are discontinuous and appear to have undergone significant secondary thickening shortly after deposition, are present in sediments deposited in the last two million years. Altered tephra are present in older sediments. New data are consistent with those reported by Quade et al. (2008), showing that tephra from Gona are typically rhyolitic, consistent with derivation from large, but distant volcanic eruptions. Significant geochemical variation is observed between different tephra layers, particularly with respect to FeO (ranging between 2 and 7.5 wt.% in different rhyolitic tephra), Ca, Mn, and Cl. Elements Na and K are variable, consistent with alkali mobility during glass hydration. Although some tephra layers contain feldspar and are thus datable using the 40Ar/39Ar, others are not directly datable, so must be geochemically linked to dated source eruptions. A unit of particular focus is the widespread marker tuff known locally as the Boolihinan tuff, which is associated with significant hominin fossils and artifacts. This locally aphyric unit, which consists of highly expanded rhyolitic glass, exhibits some geochemical variability, particularly with respect to SiO2 (74-78 wt.%), but yields a robust compositions with respect to Fe, Ca, Mn, and Cl. The Boolihinan tuff was previously tentatively correlated to a 1.6 Ma tephra found in DSDP core DEM-4-1. However, we suggest here a more robust correlation to two samples of an unwelded ignimbrite with 40Ar/39Ar ages of 1.281±0.061 and 1.253±0.041 (27-01 and 27-05 of Morgan et al., 2012) from the Melka Kunture area, which is

  11. Delayed, disequilibrium degassing in rhyolite magma: Decompression experiments and implications for explosive volcanism

    USGS Publications Warehouse

    Mangan, M.; Sisson, T.

    2000-01-01

    Recent numerical models and analog shock tube experiments show that disequilibrium degassing during magma ascent may lead to violent vesiculation very near the surface. In this study a series of decompression experiments using crystal-free, rhyolite melt were conducted to examine the development of large supersaturations due to delayed, homogenous (spontaneous) bubble nucleation. Melts were saturated at 900??C and 200 MPa with either 5.2 wt% dissolved H2O, or with 4.2 wt% H2O and 640 ppm CO2, and isothermally decompressed at linear rates of either 0.003, 0.025, or 8.5 MPa/s to final pressures between 25 and 175 MPa. Additional isobaric saturation experiments (900??C, 200-25 MPa) using pure H2O or mixed H2O-CO2 fluids establish reference equilibrium solubility curves/values. Homogenous nucleation is triggered in both H2O-only and H2O-CO2 experiments once the supersaturation pressure (??Pss) reaches ?? 120-150 MPa and the melt contains ?? two times its equilibrium water contents. Bubble number density and nucleation rate depend on the supersaturation pressure, with values on the order of 102/cm3 and < 1/cm3/s for ??Pss~120 MPa; 106/cm3 and 103-105/cm3/s for ??Pss??~130-150 MPa; and 107/cm3 and 106/cm3/s for ??Pss??160-175 MPa. Nucleation rates are consistent with classical nucleation theory, and infer an activation energy for nucleation of 1.5 x 10-18 J/nucleus, a critical bubble radius of 2 x 10-9 m, and an effective surface tension for rhyolite at 5.2 wt% H2O and 900??C of 0.10-0.11 N/m. The long nucleation delay limits the time available for subsequent diffusion such that disequilibrium dissolved H2O and CO2 contents persist to the end of our runs. The disequilibrium degassing paths inferred from our experiments contrast markedly with the equilibrium or quasi-equilibrium paths found in other studies where bubble nucleation occurs heterogenously on crystals or other discontinuities in the melt at low ??Pss. Homogenous and heterogenous nucleation rates are

  12. Rayleigh-Taylor mixing with space-dependent acceleration

    NASA Astrophysics Data System (ADS)

    Abarzhi, Snezhana

    2016-11-01

    We extend the momentum model to describe Rayleigh-Taylor (RT) mixing driven by a space-dependent acceleration. The acceleration is a power-law function of space coordinate, similarly to astrophysical and plasma fusion applications. In RT flow the dynamics of a fluid parcel is driven by a balance per unit mass of the rates of momentum gain and loss. We find analytical solutions in the cases of balanced and imbalanced gains and losses, and identify their dependence on the acceleration exponent. The existence is shown of two typical sub-regimes of self-similar RT mixing - the acceleration-driven Rayleigh-Taylor-type mixing and dissipation-driven Richtymer-Meshkov-type mixing with the latter being in general non-universal. Possible scenarios are proposed for transitions from the balanced dynamics to the imbalanced self-similar dynamics. Scaling and correlations properties of RT mixing are studied on the basis of dimensional analysis. Departures are outlined of RT dynamics with space-dependent acceleration from canonical cases of homogeneous turbulence as well as blast waves with first and second kind self-similarity. The work is supported by the US National Science Foundation.

  13. Using Taylor Expansions to Prepare Students for Calculus

    ERIC Educational Resources Information Center

    Lutzer, Carl V.

    2011-01-01

    We propose an alternative to the standard introduction to the derivative. Instead of using limits of difference quotients, students develop Taylor expansions of polynomials. This alternative allows students to develop many of the central ideas about the derivative at an intuitive level, using only skills and concepts from precalculus, and…

  14. Effects of best-management practices in Eagle and Joos Valley Creeks in the Waumandee Creek Priority Watershed, Wisconsin, 1990-2007

    USGS Publications Warehouse

    Graczyk, David J.; Walker, John F.; Bannerman, Roger T.; Rutter, Troy D.

    2012-01-01

    In many watersheds, nonpoint-source contamination is a major contributor to water-quality problems. In response to the recognition of the importance of nonpoint sources, the Wisconsin Nonpoint Source Water Pollution Abatement Program (Nonpoint Program) was enacted in 1978. This report summarizes the results of a study to assess the effectiveness of watershed-management practices for controlling nonpoint-source contamination for the Eagle Creek and Joos Valley Creek Watersheds. Streamflow-gaging stations equipped for automated sample collection and continuous recording of stream stage were installed in July 1990 at Eagle and Joos Valley Creeks and were operated through September 2007. In October 1990, three rain gages were installed in each watershed and were operated through September 2007. Best-Management Practices (BMPs) were installed during 1993 to 2000 in Eagle and Joos Valley Creeks and were tracked throughout the study period. By the year 2000, a majority of the BMPs were implemented in the two watersheds and goals set by the Wisconsin Department of Natural Resources and the local Land Conservation Department had been achieved for the two study watersheds (Wisconsin Department of Natural Resources, 1990). The distributions of the rainstorms that produced surface runoff and storm loads were similar in the pre-BMP (1990-93) and post-BMP implementation (2000-07) periods for both Eagle and Joos Valley Creeks. The highest annual streamflow occurred at both sites in water year 1993, which corresponded to the greatest above normal nonfrozen precipitation measured at two nearby NOAA weather stations. The minimum streamflow occurred in water year 2007 at both sites. Base-flow and stormwater samples were collected and analyzed for suspended solids, total phosphorus, and ammonia nitrogen. For both Eagle and Joos Valley Creeks the median concentrations of suspended solids and total phosphorus in base flow were lower during the post-BMP period compared to the pre

  15. Assessment of aquatic macroinvertebrate communities in the Autauga Creek watershed, Autauga County, Alabama, 2009

    USGS Publications Warehouse

    Mooty, Will S.; Gill, Amy C.

    2011-01-01

    Only four families within the Ephemeroptera, Plecoptera, and Trichoptera orders were found during a 1999 survey of aquatic macroinvertebrates in Autauga Creek, Autauga County, Alabama, by the Alabama Department of Environmental Management. The low number of taxa of Ephemeroptera, Plecoptera, and Trichoptera families indicated that the aquatic macroinvertebrate community was in poor condition, and the creek was placed on the Alabama Department of Environmental Management 303(d) list. The U.S. Geological Survey conducted a study in 2009 to provide data for the Alabama Department of Environmental Management and other water management agencies to re-evaluate aquatic macroinvertebrate communities in Autauga Creek to see if they meet Alabama Department of Environmental Management water-quality criteria. Aquatic macroinvertebrate communities were evaluated at three sites in the Autauga Creek watershed. Macroinvertebrates were sampled at two sites on Autauga Creek and one on Bridge Creek, the largest tributary to Autauga Creek. Water-quality field parameters were assessed at 11 sites. During the 2009 sampling, 12 families within the orders of Ephemeroptera, Plecoptera, Trichoptera were found at the Alabama Department of Environmental Management's assessment site whereas only four were found in 1999. The upstream site on Autauga Creek had consistently higher numbers of taxa than the Bridge Creek site and the lower site on Autauga Creek which is the Alabama Department of Environmental Management's assessment site. Chironomid richness was noticeably higher on the two Autauga Creek sites than the Bridge Creek site.

  16. 4. GENERAL VIEW SHOWING INDIAN CREEK (FOREGROUND) AND CULVERT. AQUEDUCT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. GENERAL VIEW SHOWING INDIAN CREEK (FOREGROUND) AND CULVERT. AQUEDUCT PASSES ABOVE CULVERT. - Old Croton Aqueduct, Indian Creek Culvert, Reservoir & Quaker Bridge Roads, Crotonville, Ossining, Westchester County, NY

  17. Streamflow conditions along Soldier Creek, Northeast Kansas

    USGS Publications Warehouse

    Juracek, Kyle E.

    2017-11-14

    The availability of adequate water to meet the present (2017) and future needs of humans, fish, and wildlife is a fundamental issue for the Prairie Band Potawatomi Nation in northeast Kansas. Because Soldier Creek flows through the Prairie Band Potawatomi Nation Reservation, it is an important tribal resource. An understanding of historical Soldier Creek streamflow conditions is required for the effective management of tribal water resources, including drought contingency planning. Historical data for six selected U.S. Geological Survey (USGS) streamgages along Soldier Creek were used in an assessment of streamflow characteristics and trends by Juracek (2017). Streamflow data for the period of record at each streamgage were used to compute annual mean streamflow, annual mean base flow, mean monthly flow, annual peak flow, and annual minimum flow. Results of the assessment are summarized in this fact sheet.

  18. Fast-growing willow shrub named `Fish Creek`

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Abrahamson, Lawrence P; Kopp, Richard F; Smart, Lawrence B

    2007-05-08

    A distinct male cultivar of Salix purpurea named `Fish Creek`, characterized by rapid stem growth producing greater than 30% more woody biomass than either of its parents (`94001` and `94006`) and 20% more biomass than a current production cultivar (`SV1`). `Fish Creek` can be planted from dormant stem cuttings, produces multiple stems after coppice, and the stem biomass can be harvested when the plant is dormant. In the spring following harvest, the plant will re-sprout very vigorously, producing new stems that can be harvested after two to four years of growth. This harvest cycle can be repeated several times. Themore » stem biomass can be chipped and burned as a source of renewable energy, generating heat and/or electricity. `Fish Creek` displays a low incidence of rust disease or damage by beetles or sawflies.« less

  19. Measuring Taylor Slough boundary and internal flows, Everglades National Park, Florida

    USGS Publications Warehouse

    Tillis, G.M.

    2001-01-01

    Four intensive data-collection efforts, intended to represent the spectrum of precipitation events and associated flow conditions, were conducted during 1997 and 1998 in the Taylor Slough Basin, Everglades National Park. Flow velocities were measured by newly developed, portable Acoustic Doppler Velocity meters along three transects bisecting the Taylor Slough Basin from east to west, roughly perpendicular to the centerline axis of the slough as well as a fourth transect along the slough's axis. These meters provided the required levels of accuracy in flow-velocity measurements while enabling the rapid collection of multiple time series of flow data at remote sites. Concurrently, flow measurements were made along bordering road culverts and under L-31W and Taylor Slough bridges. Flows across the study area's boundaries provided net flow of water into the system and transect measurements provided flow data within the basin. Collected data are available through the World Wide Web (http://sofia.usgs.gov/projects/flow_velocity/). The high-water and low-water events corresponded with the highest and lowest flow velocities, respectively. The July 1998 data had lower than expected flow velocities and, in some cases, strong winds reversed flow direction.

  20. Instability of Taylor-Sedov blast waves propagating through a uniform gas

    NASA Astrophysics Data System (ADS)

    Grun, J.; Stamper, J.; Manka, C.; Resnick, J.; Burris, R.; Crawford, J.; Ripin, B. H.

    1991-05-01

    An instability in Taylor-Sedov blast waves was measured as the waves propagated through a uniform gas with a low adiabatic index. The first measurements of the instability are given and compared to theoretical predictions. The classical Taylor-Sedov blast waves resulted from the expansion of ablation plasma into an ambient gas from laser-irradiated foils, and photographs were taken using the dark-field imaging method. Visible emission from the blasts were recorded with a four-frame microchannel-plate intensifier camera. Blast waves formed in nitrogen gas are shown to be stable and smooth, whereas the waves propagating through xenon gas are found to be unstable and wrinkled. A power law is fitted to the experimental data, and the adiabatic indices are theorized to cause the different responses in the two gases. The results generally agree with theoretical predictions in spite of some minor discrepancies, and an explanation of the instability mechanism is developed. When the adiabatic index is sufficiently low, the Taylor-Sedov blast waves in a uniform gas will be unstable, and the perturbed amplitudes will grow as a power of time.

  1. Three Important Taylor Series for Introductory Physics

    DTIC Science & Technology

    2009-09-01

    series by the sum of its first few terms is useful throughout an introductory physics course . Example applications [1, 2] include estimating square...Lat. Am. J. Phys. Educ. Vol. 3, No. 3, Sept. 2009 535 http://www.journal.lapen.org.mx Three Important Taylor Series for Introductory Physics...one dimension, which instructively ties the mathematical development to physics concepts already presented in introductory courses . Keywords

  2. View of deck truss span over creek and adjacent trestle, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of deck truss span over creek and adjacent trestle, looking due south. - Pennsylvania Railroad, Brandywine Valley Viaduct, Spanning Brandywine Creek & U.S. Route 322, Downingtown, Chester County, PA

  3. Surface water of Beaver Creek Basin, in South-Central Oklahoma

    USGS Publications Warehouse

    Laine, L.L.; Murphy, J.J.

    1962-01-01

    Annual discharge from Beaver Creek basin is estimated to have averaged 217,000 acre-feet during a 19-year base period, water years 1938-56, equivalent to an average annual runoff depth of 4.7 inches over the 857 square-mile drainage area. About 55,000 acre-feet per year comes from Little Beaver Creek basin, a tributary drainage of 195 square miles. Yearly streamflow is highly variable. The discharge of Little Beaver Creek near Duncan during 13-year period of record (water years 1949-61) has ranged from 86,530 acre-feet in calendar year 1957 to 4,880 acre-feet in 1956, a ratio of almost 18 to 1. Highest runoff within a year tends to occur in the spring months of May and June, a 2-month period that, on the average, accounts for more than half of the annual discharge of Little Beaver Creek near Duncan. The average monthly runoff during record was lowest in January. Variation in daily streamflow is such that while the average discharge for the 13-year period of record was 50.1 cfs (cubic feet per second), the daily discharge was more than 6 cfs only about half of the time. There was no flow at the site 19 percent of the time during the period. Some base runoff usually exists in the headwaters of Beaver and Little Beaver Creeks, and in the lower reaches of Beaver Creek. Low flow in Cow Creek tends to be sustained by waste water from Duncan, where water use in 1961 averaged 4 million gallons per day. In the remainder of the basin, periods of no flow occur in most years. The surface water of Beaver Creek basin is very hard but in general is usable for municipal, agricultural and industrial purposes. The chemical character of the water is predominantly a calcium, magnesium bicarbonate type of water in the lower three quarters of the basin, except in Cow Creek where oil-field brines induce a distinct sodium, calcium chloride characteristic at low and medium flows. A calcium sulfate type of water occurs in most of the northern part of the basin except in headwater areas

  4. "Bridge #6 Rock Creek: Castiron 48" pipe lines to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    "Bridge #6 - Rock Creek: Cast-iron 48" pipe lines to Gravity - 1859." Construction photo of Pennsylvania Avenue Bridge, 1859. Photograph courtesy Washington Aqueduct Division, U.S. Army Corps of Engineers - Pennsylvania Avenue Bridge, Spanning Rock Creek & Potomac Parkway, Washington, District of Columbia, DC

  5. Missing link between the Hayward and Rodgers Creek faults

    PubMed Central

    Watt, Janet; Ponce, David; Parsons, Tom; Hart, Patrick

    2016-01-01

    The next major earthquake to strike the ~7 million residents of the San Francisco Bay Area will most likely result from rupture of the Hayward or Rodgers Creek faults. Until now, the relationship between these two faults beneath San Pablo Bay has been a mystery. Detailed subsurface imaging provides definitive evidence of active faulting along the Hayward fault as it traverses San Pablo Bay and bends ~10° to the right toward the Rodgers Creek fault. Integrated geophysical interpretation and kinematic modeling show that the Hayward and Rodgers Creek faults are directly connected at the surface—a geometric relationship that has significant implications for earthquake dynamics and seismic hazard. A direct link enables simultaneous rupture of the Hayward and Rodgers Creek faults, a scenario that could result in a major earthquake (M = 7.4) that would cause extensive damage and loss of life with global economic impact. PMID:27774514

  6. Missing link between the Hayward and Rodgers Creek faults

    USGS Publications Warehouse

    Watt, Janet; Ponce, David A.; Parsons, Thomas E.; Hart, Patrick E.

    2016-01-01

    The next major earthquake to strike the ~7 million residents of the San Francisco Bay Area will most likely result from rupture of the Hayward or Rodgers Creek faults. Until now, the relationship between these two faults beneath San Pablo Bay has been a mystery. Detailed subsurface imaging provides definitive evidence of active faulting along the Hayward fault as it traverses San Pablo Bay and bends ~10° to the right toward the Rodgers Creek fault. Integrated geophysical interpretation and kinematic modeling show that the Hayward and Rodgers Creek faults are directly connected at the surface—a geometric relationship that has significant implications for earthquake dynamics and seismic hazard. A direct link enables simultaneous rupture of the Hayward and Rodgers Creek faults, a scenario that could result in a major earthquake (M = 7.4) that would cause extensive damage and loss of life with global economic impact.

  7. Positive Health Psychology: An Interview with Shelley Taylor.

    ERIC Educational Resources Information Center

    Rich, Grant Jewell

    2000-01-01

    Presents an interview with Shelley Taylor, a professor of Psychology at the University of California in Los Angles (California). Addresses topics such as how she became interested in psychology, the importance of health psychology in the curriculum, the ideal training for students in health psychology, and her work with "positive illusions." (CMK)

  8. Elevation of deck truss span over creek, looking NW along ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Elevation of deck truss span over creek, looking NW along U.S. route 322. - Pennsylvania Railroad, Brandywine Valley Viaduct, Spanning Brandywine Creek & U.S. Route 322, Downingtown, Chester County, PA

  9. Timber Creek bunkhouse and mess hall, Rocky Mountain National Park. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Timber Creek bunkhouse and mess hall, Rocky Mountain National Park. Interior, kitchen and dining area, viewing north. - Timber Creek Bunkhouse & Mess Hall, Trail Ridge Road, Grand Lake, Grand County, CO

  10. Characterizing Strength of Chaotic Dynamics and Numerical Simulation Relevant to Modified Taylor-Couette Flow with Hourglass Geometry

    NASA Astrophysics Data System (ADS)

    Hou, Yu; Kowalski, Adam; Schroder, Kjell; Halmstad, Andrew; Olsen, Thomas; Wiener, Richard

    2006-05-01

    We characterize the strength of chaos in two different regimes of Modified Taylor-Couette flow with Hourglass Geometry: the formation of Taylor Vortices with laminar flow and with turbulent flow. We measure the strength of chaos by calculating the correlation dimension and the Kaplan-Yorke dimension based upon the Lyapunov Exponents of each system. We determine the reliability of our calculations by considering data from a chaotic electronic circuit. In order to predict the behavior of the Modified Taylor-Couette flow system, we employ simulations based upon an idealized Reaction-Diffusion model with a third order non-linearity in the reaction rate. Variation of reaction rate with length corresponds to variation of the effective Reynolds Number along the Taylor-Couette apparatus. We present preliminary results and compare to experimental data.

  11. Eruptive history, geochronology, and post-eruption structural evolution of the late Eocene Hall Creek Caldera, Toiyabe Range, Nevada

    USGS Publications Warehouse

    Colgan, Joseph P.; Henry, Christopher D.

    2017-02-24

    The magmatic, tectonic, and topographic evolution of what is now the northern Great Basin remains controversial, notably the temporal and spatial relation between magmatism and extensional faulting. This controversy is exemplified in the northern Toiyabe Range of central Nevada, where previous geologic mapping suggested the presence of a caldera that sourced the late Eocene (34.0 mega-annum [Ma]) tuff of Hall Creek. This region was also inferred to be the locus of large-magnitude middle Tertiary extension (more than 100 percent strain) localized along the Bernd Canyon detachment fault, and to be the approximate location of a middle Tertiary paleodivide that separated east and west-draining paleovalleys. Geologic mapping, 40Ar/39Ar dating, and geochemical analyses document the geologic history and extent of the Hall Creek caldera, define the regional paleotopography at the time it formed, and clarify the timing and kinematics of post-caldera extensional faulting. During and after late Eocene volcanism, the northern Toiyabe Range was characterized by an east-west trending ridge in the area of present-day Mount Callaghan, probably localized along a Mesozoic anticline. Andesite lava flows erupted around 35–34 Ma ponded hundreds of meters thick in the erosional low areas surrounding this structural high, particularly in the Simpson Park Mountains. The Hall Creek caldera formed ca. 34.0 Ma during eruption of the approximately 400 cubic kilometers (km3) tuff of Hall Creek, a moderately crystal-rich rhyolite (71–77 percent SiO2) ash-flow tuff. Caldera collapse was piston-like with an intact floor block, and the caldera filled with thick (approximately 2,600 meters) intracaldera tuff and interbedded breccia lenses shed from the caldera walls. The most extensive exposed megabreccia deposits are concentrated on or close to the caldera floor in the southwestern part of the caldera. Both silicic and intermediate post-caldera lavas were locally erupted within 400 thousand

  12. 78 FR 64003 - Notice of Availability of the Final Environmental Impact Statement for the Jump Creek, Succor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-25

    ... Cow Creek Watersheds Grazing Permit Renewal, Owyhee County, ID AGENCY: Bureau of Land Management... Field Office Jump Creek, Succor Creek and Cow Creek Watersheds grazing permit renewal, and by this... in the Federal Register. ADDRESSES: Copies of the Jump Creek, Succor Creek and Cow Creek Watersheds...

  13. Dry Creek Joint Elementary School District. Educational Specifications: Dry Creek Middle School.

    ERIC Educational Resources Information Center

    Dry Creek Joint Elementary School District, Roseville, CA.

    An Educational Specification Committee was convened to determine the design specifications required for a new middle school in Roseville, California's Dry Creek District. This report presents revisions to an earlier document that examined school room specifications for each grade level and administrative area. Specification considerations are…

  14. Boulder Creek Study

    ERIC Educational Resources Information Center

    Bingaman, Deirdre; Eitel, Karla Bradley

    2010-01-01

    Boulder Creek runs literally in the backyard of Donnelly Elementary School and happens to be on the EPA list of impaired water bodies. Therefore, a unique opportunity for problem solving opened the door to an exciting chance for students to become scientists, while also becoming active in their community. With the help of the Idaho Department of…

  15. Detail view of Fanno Creek trestle, showing trestle substructure, view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view of Fanno Creek trestle, showing trestle substructure, view looking north - Oregon Electric Railroad, Fanno Creek Trestle, Garden Home to Wilsonville Segment, Milepost 34.7, Garden Home, Washington County, OR

  16. 2. Historic American Buildings Survey Everitt K. Taylor, Photographer September ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey Everitt K. Taylor, Photographer September 15, 1936 EXTERIOR - EAST ELEVATION FROM OLD PRINT IN POSSESSION OF OWNER - Governor's House, 149 Kearny Avenue, Perth Amboy, Middlesex County, NJ

  17. 78 FR 26065 - Notice of Availability of the Draft Environmental Impact Statement for the Jump Creek, Succor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-03

    ... Cow Creek Watersheds Grazing Permit Renewal, ID AGENCY: Bureau of Land Management, Interior. ACTION... the Jump Creek, Succor Creek, and Cow Creek Watersheds Grazing Permit Renewal and by this notice is... receive written comments on the Draft EIS for the Jump Creek, Succor Creek, and Cow Creek Watersheds...

  18. Two Distinct Sets of Magma Sources in Cretaceous Rocks From Magnet Cove, Prairie Creek, and Other Igneous Centers of the Arkansas Alkaline Province, USA

    NASA Astrophysics Data System (ADS)

    Duke, G. I.; Carlson, R. W.; Eby, G. N.

    2008-12-01

    Two distinct sets of magma sources from the Arkansas alkaline province (~106-89 Ma) are revealed by Sr-Nd-Pb isotopic compositions of olivine lamproites vs. other alkalic rock types, including carbonatite, ijolite, lamprophyres, tephrite, malignite, jacupirangite, phonolite, trachyte, and latite. Isotopic compositions of diamond-bearing olivine lamproites from Prairie Creek and Dare Mine Knob point to Proterozoic lithosphere as an important source, and previous Re-Os isotopic data indicate derivation from subcontinental mantle lithosphere. Both sources were probably involved in lamproite generation. Magnet Cove carbonatites and other alkalic magmas were likely derived from an asthenospheric source. Lamproite samples are isotopically quite different from other rock types in Sr-Nd-Pb isotopic space. Although three lamproite samples from Prairie Creek have a large range of SiO2 contents (40-60 wt %), initial values of ɛNd (-10 to -13), 206Pb/204Pb (16.61-16.81), 207Pb/204Pb (15.34-15.36), and 208Pb/204Pb (36.57-36.76) are low and similar. Only 87Sr/86Sr(i) displays a wide range in the Prairie Creek lamproites (0.70627-0.70829). A fourth lamproite from Dare Mine Knob has the most negative ɛNd(i) of -19. Lamproite isotope values show a significant crustal component and isotopically overlap subalkalic rhyolites from the Black Hills (SD), which assimilated Proterozoic crust. Six samples of carbonatite, ijolite, and jacupirangite from Magnet Cove and Potash Sulphur Springs exhibit the most depleted Sr-Nd isotopic signatures of all samples. For these rock types, 87Sr/86Sr(i) is 0.70352 - 0.70396, and ɛNd(i) is +3.8 - +4.3. Eight other rock types have a narrow range of ɛNd(i) (+1.9 - +3.7), but a wide range of 87Sr/86Sr(i) (0.70424 - 0.70629). These 14 samples comprise a fairly tight cluster of Pb isotopic values: 206Pb/204Pb (18.22-19.23), 207Pb/204Pb (15.54-15.62), and 208Pb/204Pb (38.38-38.94), suggesting very little crustal assimilation. They are most similar to EM-2

  19. Surficial geology of the Cane Creek basin, Lauderdale County, Tennessee

    USGS Publications Warehouse

    Miller, J.H.

    1991-01-01

    The surficial geology of the Cane Creek basin, in Lauderdale County, West Tennessee, was studied from 1985-88. Peoria Loess is the parent material from which soils in the Cane Creek drainage basin were derived. In general, a brown silt grades into a gray silt from 5 to I7 feet below ground surface. This color change probably represents depth to water table prior to the channelization of Cane Creek. Only at river mile 11.9 does rock outcrop near the main channel. Lower reaches of major tributaries have surficial geology similar to the main channel. In upper reaches of Hyde Creek and Fain Spring Creek, the sequence from the St&ace is sand and gravels, red-brown sandstone, sand and clay layers, and then, an orange sand layer. Coarse-grained deposits are found most often along the northern boundary of the basin and only occasionally in areas to the west and south of the main channel. Depth to sand or gravel ranges from about 0 to 158 feet in the uplands, and generally deeper than 40 feet near the main channel.

  20. Investigating the Maya Polity at Lower Barton Creek Cayo, Belize

    NASA Astrophysics Data System (ADS)

    Kollias, George Van, III

    The objectives of this research are to determine the importance of Lower Barton Creek in both time and space, with relation to other settlements along the Belize River Valley. Material evidence recovered from field excavations and spatial information developed from Lidar data were employed in determining the socio-political nature and importance of this settlement, so as to orient its existence within the context of ancient socio-political dynamics in the Belize River Valley. Before the investigations detailed in this thesis no archaeological research had been conducted in the area, the site of Lower Barton Creek itself was only recently identified via the 2013 West-Central Belize LiDAR Survey (WCBLS 2013). Previously, the southern extent of the Barton Creek area represented a major break in our knowledge not only of the Barton Creek area, but the southern extent of the Belize River Valley. Conducting research at Lower Barton Creek has led to the determination of the polity's temporal existence and allowed for a greater and more complex understanding of the Belize River Valley's interaction with regions abutting the Belize River Valley proper.

  1. Sediment-transport characteristics of Cane Creek, Lauderdale County, Tennessee

    USGS Publications Warehouse

    Carey, W.P.

    1993-01-01

    An investigation of the sediment-transport characteristics of Cane Creek in Lauderdale County, Tennessee, was conducted from 1985-88 to evaluate the potential for channel erosion induced by modifications (realignment and enlargement) and the potential ability of different flows to move bed and bank stabilizing material. Frequently occurring flows in Cane Creek are capable of moving sand-size material (0.0625 - 4.0 millimeters). During floods that equal or exceed the 2-year flood, Cane Creek is capable of moving very coarse gravel (32 - 64 millimeters). Boundary-shear values at bridges, where flow contractions occur, correspond to critical diameters in excess of 100 millimeters. Thus, the areas near bridges, where channel stability is most critical, are the areas where erosive power is greatest. Deepening and widening of Cane Creek has exposed large areas of channel boundary that are a significant source of raindrop-detached sediment during the early stages of a storm before stream flow increases signifi- cantly. This causes suspended-sediment concentration to peak while the flow hydrograph is just beginning to rise. For basins like Cane Creek, where runoff events commonly last less than a day and where variation in discharge and sediment concentrations are large, an estimate of sediment yield based on periodic observations of instantaneous values is subject to considerable uncertainty.

  2. 14. VIEW OF CEDAR MILL CREEK TRESTLE FROM TRESTLE OVER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. VIEW OF CEDAR MILL CREEK TRESTLE FROM TRESTLE OVER CEDAR MILL CREEK ON SPUR LINE, FACING SOUTHWEST - Oregon Electric Railway Westside Corridor, Between Watson & 185th Avenues, Beaverton, Washington County, OR

  3. Pediatric and adolescent applications of the Taylor Spatial Frame.

    PubMed

    Paloski, Michael; Taylor, Benjamin C; Iobst, Christopher; Pugh, Kevin J

    2012-06-01

    Limb deformity can occur in the pediatric and adolescent populations from multiple etiologies: congenital, traumatic, posttraumatic sequelae, oncologic, and infection. Correcting these deformities is important for many reasons. Ilizarov popularized external fixation to accomplish this task. Taylor expanded on this by designing an external fixator in 1994 with 6 telescoping struts that can be sequentially manipulated to achieve multiaxial correction of deformity without the need for hinges or operative frame alterations. This frame can be used to correct deformities in children and has shown good anatomic correction with minimal morbidity. The nature of the construct and length of treatment affects psychosocial factors that the surgeon and family must be aware of prior to treatment. An understanding of applications of the Taylor Spatial Frame gives orthopedic surgeons an extra tool to correct simple and complex deformities in pediatric and adolescent patients. Copyright 2012, SLACK Incorporated.

  4. Taylor bubbles in liquid filled annuli: Some new observations

    NASA Astrophysics Data System (ADS)

    Agarwal, V.; Jana, A. K.; Das, G.; Das, P. K.

    2007-10-01

    Taylor bubbles rising through a vertical concentric annulus do not wrap around the inner tube completely. The two edges of the bubble are separated by a liquid bridge which increases with an increase of the inner radius. However, the change in the shape of the Taylor bubbles in annuli with extremely small inner diameter has not yet been reported. In the present investigation, several experiments have been performed in circular and noncircular annuli to understand the influence of the inner and outer wall on the bubble shape. The bubble has been observed to assume a completely different shape in both circular and square annuli with a very thin inner rod. Nevertheless, the rise velocity for such situations agree with the prediction of the model proposed by Das et al. [Chem. Eng. Sci. 53, 977 (1998)] when the outer pipe is circular but fails for a square outer pipe.

  5. Depositional environments, sequence stratigraphy, and trapping mechanisms of Fall River Formation in Donkey Creek and Coyote Creek oil fields, Powder River basin, Wyoming

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Knox, P.R.

    1989-09-01

    Donkey Creek and Coyote Creek fields contain combined reserves of approximately 35 million bbl of oil and are within a trend of fields on the eastern flank of the Powder River basin that totals over 100 million bbl of reserves. The principal producing formation is the Lower Cretaceous Fall River Sandstone. A study of 45 cores and 248 logs from the three pools in the Donkey Creek and Coyote fields has shown that the Fall River is composed of three progradational deltaic units deposited during a period of rising relative sea level. These are locally eroded and are filled bymore » a fluvial point-bar complex deposited following a lowering of relative sea level. Four important depositional facies have been recognized: the delta-front and distributary-channel sandstone of the highstand deltaic sequence and the point-bar sandstone and channel-abandonment of the lowstand fluvial sequence. Stratigraphic traps in Coyote Creek and south Donkey Creek pools are the result of permeable (250 md) point-bar sandstone (250 bbl oil/day ip) bounded updip by impermeable (0.1 md) channel abandonment mudstone. Most of the oil in the central Donkey Creek pool is produced from permeable (76 md) distributary-channel sandstone (150 bbl oil/day ip), which is restricted to the western flank of a structural nose. Lesser production, on the crest and upper western flank of the structure, is obtained from the less permeable (2.8 md) delta-front sandstone (50 bbl oil/day ip). Production is possibly limited to the crest and western flank by hydrodynamic processes.« less

  6. Magnetic helicity balance at Taylor relaxed states sustained by AC helicity injection

    NASA Astrophysics Data System (ADS)

    Hirota, Makoto; Morrison, Philip J.; Horton, Wendell; Hattori, Yuji

    2017-10-01

    Magnitudes of Taylor relaxed states that are sustained by AC magnetic helicity injection (also known as oscillating field current drive, OFCD) are investigated numerically in a cylindrical geometry. Compared with the amplitude of the oscillating magnetic field at the skin layer (which is normalized to 1), the strength of the axial guide field Bz 0 is shown to be an important parameter. The relaxation process seems to be active only when Bz 0 < 1 . Moreover, in the case of weak guide field Bz 0 < 0.2 , a helically-symmetric relaxed state is self-generated instead of the axisymmetric reversed-field pinch. As a theoretical model, the helicity balance is considered in a similar way to R. G. O'Neill et al., where the helicity injection rate is directly equated with the dissipation rate at the Taylor states. Then, the bifurcation to the helical Taylor state is predicted theoretically and the estimated magnitudes of the relaxed states reasonably agree with numerical results as far as Bz 0 < 1 . This work was supported by JSPS KAKENHI Grant Number 16K05627.

  7. Flood-inundation maps for Suwanee Creek from the confluence of Ivy Creek to the Noblin Ridge Drive bridge, Gwinnett County, Georgia

    USGS Publications Warehouse

    Musser, Jonathan W.

    2012-01-01

    Digital flood-inundation maps for a 6.9-mile reach of Suwanee Creek, from the confluence of Ivy Creek to the Noblin Ridge Drive bridge, were developed by the U.S. Geological Survey (USGS) in cooperation with Gwinnett County, Georgia. The inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage at Suwanee Creek at Suwanee, Georgia (02334885). Current stage at this USGS streamgage may be obtained at http://waterdata.usgs.gov/ and can be used in conjunction with these maps to estimate near real-time areas of inundation. The National Weather Service (NWS) is incorporating results from this study into the Advanced Hydrologic Prediction Service (AHPS) flood-warning system (http://water.weather.gov/ahps/). The NWS forecasts flood hydrographs at many places that commonly are collocated at USGS streamgages. The forecasted peak-stage information for the USGS streamgage at Suwanee Creek at Suwanee (02334885), available through the AHPS Web site, may be used in conjunction with the maps developed in this study to show predicted areas of flood inundation. A one-dimensional step-backwater model was developed using the U.S. Army Corps of Engineers HEC-RAS software for Suwanee Creek and was used to compute flood profiles for a 6.9-mile reach of the creek. The model was calibrated using the most current stage-discharge relations at the Suwanee Creek at Suwanee streamgage (02334885). The hydraulic model was then used to determine 19 water-surface profiles for flood stages at the Suwanee Creek streamgage at 0.5-foot intervals referenced to the streamgage. The profiles ranged from just above bankfull stage (7.0 feet) to approximately 1.7 feet above the highest recorded water level at the streamgage (16.0 feet). The simulated water-surface profiles were then combined

  8. The Influence of Phenocrysts on Magma Degassing in Rhyolitic Systems

    NASA Astrophysics Data System (ADS)

    deGraffenried, R.; Larsen, J. F.; Lindoo, A. N.

    2016-12-01

    The kinetics of volatile exsolution and magma degassing control volcanic eruption styles, but the role of phenocrysts in the degassing process is poorly understood. The focus of this study is two series of decompression experiments examining how phenocrysts may or may not influence vesicle structures leading to permeability development and degassing in magmas with rhyolitic matrix melts. Powdered rhyolite obsidian (75 SiO2 wt. %; Mono Craters, CA) was seeded with 20 and 40 vol. % euhedral corundum crystals (350 μm) to approximate phenocrysts. Experiments were run using TZM (Ti-Zr-Mo alloy) vessels fitted with a water-cooled rapid quench top in a vertical Deltech furnace. Each run was held at 110 MPa and 900OC for 24 hours then decompressed continuously at a rate of 0.25 MPa/s to a final pressure (Pf) between 75 and 15 MPa. Permeability was measured using a bench-top permeameter constructed for the small experimental samples. Porosity was obtained from reflected light images using NIH Image J. The porosity of the samples increased from 11.0±1.7 to 73.3±3.1 vol % at Pf of 75 to 15 MPa for crystal free samples, 30.1±6.9 to 62.2±2.6 vol % at Pf of of 75 to 25 MPa for 20 vol % crystal samples, and 13.3±2.5 to 41.2±9.6 vol % at Pf of 75 to 50 MPa for 40 vol % crystal samples. The 20 vol % samples are impermeable up to at least 50 MPa Pf. The 40 vol % samples are impermeable up to 25 MPa Pf, with one sample having a measured Darcian permeability of -13.93±0.05 m2 at 25 MPa Pf. Comparatively, the crystal free samples were mostly impermeable up to 15 MPa, with one sample having a measured Darcian permeability of -14.41±0.04 m2 at 15 MPa Pf and 73.3 vol % porosity. Although preliminary, our permeable 40 vol % experiment suggests the phenocrysts help the samples develop permeability at a higher ending pressure and potentially lower porosity. Differences in the porosity curve as a function of pressure between the 20 and 40 vol % series indicate phenocrysts influence

  9. WILLOW CREEK RECLAMATION PROJECT

    EPA Science Inventory

    Working in cooperation with the EPA, Colorado Division of Minerals and Geology, and others, the Willow Creek Reclamation Committee (WCRC) will investigate the sources and character of water entering the mine workings on the Amethyst vein near the town of Creede, Colorado. Activi...

  10. 75 FR 3195 - Ochoco National Forest, Lookout Mountain Ranger District; Oregon; Mill Creek; Allotment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-20

    ...; Oregon; Mill Creek; Allotment Management Plans EIS AGENCY: Forest Service, USDA. ACTION: Notice of intent... allotments on the Lookout Mountain Ranger District. These four allotments are: Cox, Craig, Mill Creek, and..., Mill Creek and Old Dry Creek allotments. The responsible official will also decide how to mitigate...

  11. Taylor-Made Education: The Influence of the Efficiency Movement on the Testing of Reading Skills.

    ERIC Educational Resources Information Center

    Allen, JoBeth

    Much of what has developed in the testing of reading harkens back to the days of the "Cult of Efficiency" movement in education that can be largely attributed to Frederick Winslow Taylor. Taylor spent most of his productive years studying time and motion in an attempt to streamline industrial production so that people could work as…

  12. Asymmetric bursting of Taylor bubble in inclined tubes

    NASA Astrophysics Data System (ADS)

    Rana, Basanta Kumar; Das, Arup Kumar; Das, Prasanta Kumar

    2016-08-01

    In the present study, experiments have been reported to explain the phenomenon of approach and collapse of an asymmetric Taylor bubble at free surface inside an inclined tube. Four different tube inclinations with horizontal (30°, 45°, 60° and 75°) and two different fluids (water and silicon oil) are considered for the experiment. Using high speed imaging, we have investigated the approach, puncture, and subsequent liquid drainage for re-establishment of the free surface. The present study covers all the aspects in the collapse of an asymmetric Taylor bubble through the generation of two films, i.e., a cap film which lies on top of the bubble and an asymmetric annular film along the tube wall. Retraction of the cap film is studied in detail and its velocity has been predicted successfully for different inclinations and fluids. Film drainage formulation considering azimuthal variation is proposed which also describes the experimental observations well. In addition, extrapolation of drainage velocity pattern beyond the experimental observation limit provides insight into the total collapse time of bubbles at different inclinations and fluids.

  13. 1. Historic American Buildings Survey Everitt K. Taylor, Photographer September ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Everitt K. Taylor, Photographer September 15, 1936 EXTERIOR - GENERAL VIEW EAST ELEVATION FROM OLD PRINT IN POSSESSION OF OWNER - Governor's House, 149 Kearny Avenue, Perth Amboy, Middlesex County, NJ

  14. A model that helps explain Sr-isotope disequilibrium between feldspar phenocrysts and melt in large-volume silicic magma systems

    USGS Publications Warehouse

    Duffield, W.A.; Ruiz, J.

    1998-01-01

    Feldspar phenocrysts of silicic volcanic rocks are commonly in Sr-isotopic disequilibrium with groundmass. In some cases the feldspar is more radiogenic, and in others it is less radiogenic. Several explanations have been published previously, but none of these is able to accommodate both senses of disequilibrium. We present a model by which either more- or less-radiogenic feldspar (or even both within a single eruptive unit) can originate. The model requires a magma body open to interaction with biotite- and feldspar-bearing wall rock. Magma is incrementally contaminated as wall rock melts incongruently. Biotite preferentially melts first, followed by feldspar. Such melting behavior, which is supported by both field and experimental studies, first contaminates magma with a relatively radiogenic addition, followed by a less-radiogenic addition. Feldspar phenocrysts lag behind melt (groundmass of volcanic rock) in incorporating the influx of contaminant, thus resulting in Sr-isotopic disequilibrium between the crystals and melt. The sense of disequilibrium recorded in a volcanic rock depends on when eruption quenches the contamination process. This model is testable by isotopic fingerprinting of individual feldspar crystals. For a given set of geologic boundary conditions, specific core-to-rim Sr-isotopic profiles are expectable. Moreover, phenocrysts that nucleate at different times during the contamination process should record different and predictable parts of the history. Initial results of Sr-isotopic fingerprinting of sanidine phenocrysts from the Taylor Creek Rhyolite are consistent with the model. More tests of the model are desirable.Feldspar phenocrysts of silicic volcanic rocks are commonly in Sr-isotopic disequilibrium with groundmass. In some cases the feldspar is more radiogenic, and in others it is less radiogenic. Several explanations have been published previously, but none of these is able to accommodate both senses of disequilibrium. We present a

  15. Effects of wastewater effluent discharge on stream quality in Indian Creek, Johnson County, Kansas

    USGS Publications Warehouse

    Graham, Jennifer L.; Foster, Guy M.

    2014-01-01

    Contaminants from point and other urban sources affect stream quality in Indian Creek, which is one of the most urban drainage basins in Johnson County, Kansas. The Johnson County Douglas L. Smith Middle Basin and Tomahawk Creek Wastewater Treatment Facilities discharge to Indian Creek. Data collected by the U.S. Geological Survey, in cooperation with Johnson County Wastewater, during June 2004 through June 2013 were used to evaluate stream quality in Indian Creek. This fact sheet summarizes the effects of wastewater effluent discharge on physical, chemical, and biological conditions in Indian Creek downstream from the Douglas L. Smith Middle Basin and Tomahawk Creek Wastewater Treatment Facilities.

  16. Suspended-sediment and turbidity responses to sediment and turbidity reduction projects in the Beaver Kill, Stony Clove Creek, and Warner Creek, Watersheds, New York, 2010–14

    USGS Publications Warehouse

    Siemion, Jason; McHale, Michael R.; Davis, Wae Danyelle

    2016-12-05

    Suspended-sediment concentrations (SSCs) and turbidity were monitored within the Beaver Kill, Stony Clove Creek, and Warner Creek tributaries to the upper Esopus Creek in New York, the main source of water to the Ashokan Reservoir, from October 1, 2010, through September 30, 2014. The purpose of the monitoring was to determine the effects of suspended-sediment and turbidity reduction projects (STRPs) on SSC and turbidity in two of the three streams; no STRPs were constructed in the Beaver Kill watershed. During the study period, four STRPs were completed in the Stony Clove Creek and Warner Creek watersheds. Daily mean SSCs decreased significantly for a given streamflow after the STRPs were completed. The most substantial decreases in daily mean SSCs were measured at the highest streamflows. Background SSCs, as measured in water samples collected in upstream reference stream reaches, in all three streams in this study were less than 5 milligrams per liter during low and high streamflows. Longitudinal stream sampling identified stream reaches with failing hillslopes in contact with the stream channel as the primary sediment sources in the Beaver Kill and Stony Clove Creek watersheds.

  17. 13. VIEW FROM CEDAR MILL CREEK TRESTLE NEAR MERLO ROAD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. VIEW FROM CEDAR MILL CREEK TRESTLE NEAR MERLO ROAD TOWARD TRESTLE ON SPUR TRACK OVER CEDAR MILL CREEK, FACING NORTHEAST - Oregon Electric Railway Westside Corridor, Between Watson & 185th Avenues, Beaverton, Washington County, OR

  18. 76 FR 9968 - Drawbridge Operation Regulation; Chickasaw Creek, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-23

    ... Creek, mile 0.0, in Mobile, Alabama. The deviation is necessary to replace railroad ties on the bridge...-9826. SUPPLEMENTARY INFORMATION: CSX Transportation requested a temporary deviation from the operating schedule for the Swing Span Bridge across Chickasaw Creek, mile 0.0, in Mobile, Alabama. The bridge has a...

  19. Tree ecophysiology research at Taylor Woods (P-53)

    Treesearch

    Thomas E. Kolb; Nate G. McDowell

    2008-01-01

    We summarize the key findings of tree ecophysiology studies performed at Taylor Woods, Fort Valley Experimental Forest, Arizona between 1994 and 2003 that provide unique insight on impacts of long-term stand density management in ponderosa pine forests on tree water relations, leaf gas exchange, radial growth, leaf area-to-sapwood-area ratio, growth efficiency, leaf...

  20. Kinetic model for the short-term dissolution of a rhyolitic glass

    USGS Publications Warehouse

    White, A.F.; Claassen, H.C.

    1980-01-01

    Aqueous dissolution experiments with the vitric phase of a rhyolitic tuff were performed at 25??C and constant pH in the range 4.5-7.5. Results suggest interchange of aqueous hydrogen ions for cations situated both on the surface and within the glass. At time intervals from 24 to 900 hr., dissolution kinetics are controlled by ion transport to and from sites within the glass. Experimental data indicate that parabolic diffusion rate of a chemical species from the solid is a nonlinear function of its aqueous concentration. A numerical solution to Fick's second law is presented for diffusion of sodium, which relates it's aqueous concentration to it's concentration on glass surface, by a Freundlich adsorption isotherm. The pH influence on sodium diffusion in the model can be accounted for by use of a pH-dependent diffusion coefficient and a pH-independent adsorption isotherm. ?? 1980.