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  1. The San Franciscan volcanic field, Arizona

    Science.gov (United States)

    Robinson, Henry Hollister

    1913-01-01

    LOCATION OF AREAThe San Franciscan volcanic field, which takes its name from San Francisco Mountain, the largest volcano of the group, covers about 3,000 square miles in the north-central part of Arizona, as shown by the shaded space on the index map forming figure 1. The center of the field lies about 50 miles south of the Grand Canyon of the Colorado and the southern boundary is in part coterminous with that of the San Francisco Plateau, which forms the southwestern division of the great Colorado Plateau.The region is easily reached, for the main line of the Atchison, Topeka, & Santa Fe Railway traverses it from east to west for more than 60 miles. Flagstaff, a town of 1,500 inhabitants 10 miles south of the summit of San Francisco Mountain, is on the railroad, amid a branch line runs from Williams, 34 miles farther west, to the Grand Canyon. All the more important points of interest in the field may be reached without difficulty by wagon, and outfits may be obtained at Flagstaff.OUTLINE OF THE REPORTThis report deals primarily with the volcanic phenomena of the region as determined in the field and laboratory. Chapter I contains a brief description of the geography of the field and Chapter II is devoted largely to the sedimentary formations and structure. The rest of the report Chapters III to VI—treats entirely of the various features of the volcanoes and igneous rocks, both individually and collectively. Detailed descriptions of the volcanoes and lava fields are given in Chapter III; the volcanic history of the region and its correlation with the general history of the surrounding country are presented in Chapter IV. These two chapters will presumably suffice for the general reader who may desire to become acquainted with the broader volcanic features of the region. Chapter V (Petrography) is devoted entirely to the detailed description of the individual igneous rocks of the region, as represented by a selected set of type specimens. In Chapter VI (Petrology

  2. San Francisco Volcanic Field, Arizona, as AN Analog for Lunar and Martian Surface Exploration

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    Young, K. E.; Hodges, K.; Eppler, D.; Horz, F.; Lofgren, G. E.; Hurtado, J. M.; Desert Rats Science Team

    2010-12-01

    Terrestrial analog sites are an important tool that planetary geologists and engineers can use to examine both the geologic processes that shape other planetary surfaces as well as to develop and test technologies that are needed for the exploration of planetary surfaces. During the Apollo era, sites like Meteor Crater, Arizona, were used to train astronauts in the protocols and practices of field geology so that their lunar surface activities would be more geologically productive and efficient. As we enter a new period of planetary surface exploration, analogs will be increasingly important in preparing the next generation of both human and robotic planetary explorers. No single analog will be representative of another planetary surface, but testing technologies in a variety of settings will provide NASA and other space agencies with the operational knowledge needed to launch exploratory missions. The site we present here is one of many that can be used to explore surface operations on other planetary surfaces. The San Francisco Volcanic Field (SFVF), containing both SP Crater and Black Point Lava Flow (BPLF), Arizona, is currently being used as the test site for the Desert Research and Technology Studies (D-RATS) field test, coordinated by Johnson Space Center (JSC) and involving several other NASA centers. During the 2010 test, two habitat rovers (Space Exploration Vehicles, or SEVs) operated simultaneously, each with one astronaut crewmember and one geologist crewmember. The mission lasted 14 days and traversed some 150 km. The geologic setting of SFVF includes a series of ~2 Ma basaltic lava flows overlying Triassic sedimentary rocks, both among the predominant rock types that are found primarily on Mars. SFVF has also been identified as an analog to the Marius Hills on the Moon, a Constellation site of interest. In addition, D-RATS 2010 is simulating operational scenarios based on notional traverses near the Malapert Massif on the lunar surface. While SFVF is

  3. On the Trail of Missing Heat: Forward Gravity Modeling of the San Francisco Volcanic Field, Northern Arizona

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    Fry, B. N.; Morgan, P.

    2003-12-01

    The San Francisco volcanic field is a Quaternary field in northern Arizona, the age and size of which suggests there is a high possibility for an associated exploitable high temperature geothermal resource. Sunset Crater, the youngest dated feature in the field, erupted less than 1000 years ago. The youngest felsic volcanism in the area, located near Strawberry Crater, has been dated at about 51,000 years b.p. Felsic magmas are viscous, and therefore felsic magmatism is generally associated with upper crustal plutons, whereas mafic magmas commonly form surface flows. Heat from felsic magmatism tends to remain near subsurface ponds of the magma. Felsic magmatic systems can sustain substantial geothermal heat for tens to hundreds of thousands of years after emplacement. Knowledge of the quantity and distribution of felsic magmatism is therefore paramount to understanding the geothermal potential of the field. Surface heat flow in the study area ranges from ˜20 to ˜50 mW/m2, anomalously low for the region. Hydrological characteristics of the San Francisco volcanic field are thought to mask increased surface heat flow from the magmatic system. The deep water table (>300m) and a 2-level hydraulic system prevent characteristic surface manifestations of hydrothermal potential, such as hot springs and elevated surface heat flow. Lack of these thermal features at the surface precludes analysis of the resource based solely on surficial mapping and measurements. Forward modeling of the gravity field of a 50 km x 45 km area covering the eastern San Francisco volcanic field has been completed. Results suggest that a large felsic body ( ˜-0.15 g/cc contrast) trends northeastward under the Sugarloaf Mountain-O'Leary Peak-Strawberry Crater magmatic trend. This trend parallels a regional basement fabric, likely of early- to middle-Proterozoic origin. These results are being correlated with new surface geologic mapping and radiometric dating of young felsic volcanic rocks to

  4. Prehistoric Agriculture and Soil Fertility on Lava Flows in Northern Arizona, USA: Results from the San Francisco Volcanic Field REU

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    Broadman, E.; Anderson, K. C.

    2013-12-01

    The San Francisco Volcanic Field in northern Arizona is home to ~600 cinder cones, the youngest of which is Sunset Crater (erupted ~AD 1100). This study documents trends in available phosphate and nitrate content with time, testing whether lowered soil pH from the addition of Sunset cinders increased soil fertility and became a factor in Anasazi agricultural success. Soil fertility is examined both before and after Sunset's eruption in soils of different ages that have developed from eolian deposition on top of lava flows. An increase in phosphate and nitrate levels following acidification would suggest that the presence of Sunset cinders brought the soils to the optimal pH for mobilization of these nutrients. The combined effects of the cinder layer retaining nutrients and water, wetter climates, and increases in phosphate and nitrate (both limiting nutrients for plant growth), would have contributed to Anasazi agricultural success after Sunset's eruption. Samples for this study were taken from eolian-derived soils of different ages atop lava flows in the San Francisco Volcanic Field. OSL data from these soils on Strawberry and SP Craters' lava flows yielded age estimates of ~12.3 ka (Strawberry) and ~32.7 ka (SP), on which a soil chronosequence was based. Results from the chronosequence supported these OSL ages, indicating that soils on the SP flow are older than those on the Strawberry flow. Field descriptions, Harden Development Indices, particle size analysis, and nutrient content analysis were used for this aspect of the project. An experimental acid wash method will be used to simulate the addition of Sunset's acidic cinders, and will yield data for phosphate and nitrate content after Sunset erupted. Preliminary results indicate that phosphate and nitrate accumulate in upper, eolian-derived horizons (Av, Bw) and in more deeply buried carbonate horizons (Bk). Higher concentrations of phosphate and nitrate were found in older (SP) soils than younger

  5. Database compilation for the geologic map of the San Francisco volcanic field, north-central Arizona

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    Bard, Joseph A.; Ramsey, David W.; Wolfe, Edward W.; Ulrich, George E.; Newhall, Christopher G.; Moore, Richard B.; Bailey, Norman G.; Holm, Richard F.

    2016-01-08

    The main component of this publication is a geologic map database prepared using geographic information system (GIS) applications. The geodatabase of geologic points, lines, and polygons was produced as a compilation from five adjoining map sections originally published as printed maps in 1987 (see references in metadata). Four of the sections (U.S. Geological Survey Miscellaneous Field Studies Maps MF–1957, MF–1958, MF–1959, MF–1960) were created by scanning and geo-referencing stable base map material consisting of mylar positives. The final section (MF–1956) was compiled by hand tracing an enlargement of the available printed paper base map onto mylar using a #00 rapidograph pen, the mylar positive was then digitally scanned and geo-referenced. This method was chosen because the original basemap materials (mylar positives) for the MF–1956 section were unavailable at the time of this publication. Due to the condition of the available MF–1956 map section used as the base (which had previously been folded) the accuracy within the boundary of the MF–1956 section is presumed to be degraded in certain areas. The locations of the degraded areas and the degree of degradation within these areas is unclear. Final compilation of the database was completed using the ArcScan toolset, and the Editor toolset in ESRI ArcMap 10.1. Polygon topology was created from the lines and labels were added to the resultant geological polygons, lines, and points. Joseph A. Bard and David W. Ramsey updated and corrected the geodatabase, created the metadata and web presence, and provided the GIS-expertise to bring the geodatabase and metadata to completion. Included are links to files to view or print the original map sheets and the accompanying pamphlets.

  6. NASA Desert RATS 2010: Preliminary Results for Science Operations Conducted in the San Francisco Volcanic Field, Arizona

    Science.gov (United States)

    Gruener, J. E.; Lofgren, G. E.; Bluethmann, W. J.; Bell, E. R.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) is working with international partners to develop the space architectures and mission plans necessary for human spaceflight beyond earth orbit. These mission plans include the exploration of planetary surfaces with significant gravity fields. The Apollo missions to the Moon demonstrated conclusively that surface mobility is a key asset that improves the efficiency of human explorers on a planetary surface. NASA's Desert Research and Technology Studies (Desert RATS) is a multi-year series tests of hardware and operations carried out annually in the high desert of Arizona. Conducted since 1998, these activities are designed to exercise planetary surface hardware and operations in relatively harsh climatic conditions where long-distance, multi-day roving is achievable

  7. Assessment of planetary geologic mapping techniques for Mars using terrestrial analogs: The SP Mountain area of the San Francisco Volcanic Field, Arizona

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    Tanaka, K.L.; Skinner, J.A.; Crumpler, L.S.; Dohm, J.M.

    2009-01-01

    We photogeologically mapped the SP Mountain region of the San Francisco Volcanic Field in northern Arizona, USA to evaluate and improve the fidelity of approaches used in geologic mapping of Mars. This test site, which was previously mapped in the field, is chiefly composed of Late Cenozoic cinder cones, lava flows, and alluvium perched on Permian limestone of the Kaibab Formation. Faulting and folding has deformed the older rocks and some of the volcanic materials, and fluvial erosion has carved drainage systems and deposited alluvium. These geologic materials and their formational and modificational histories are similar to those for regions of the Martian surface. We independently prepared four geologic maps using topographic and image data at resolutions that mimic those that are commonly used to map the geology of Mars (where consideration was included for the fact that Martian features such as lava flows are commonly much larger than their terrestrial counterparts). We primarily based our map units and stratigraphic relations on geomorphology, color contrasts, and cross-cutting relationships. Afterward, we compared our results with previously published field-based mapping results, including detailed analyses of the stratigraphy and of the spatial overlap and proximity of the field-based vs. remote-based (photogeologic) map units, contacts, and structures. Results of these analyses provide insights into how to optimize the photogeologic mapping of Mars (and, by extension, other remotely observed planetary surfaces). We recommend the following: (1) photogeologic mapping as an excellent approach to recovering the general geology of a region, along with examination of local, high-resolution datasets to gain insights into the complexity of the geology at outcrop scales; (2) delineating volcanic vents and lava-flow sequences conservatively and understanding that flow abutment and flow overlap are difficult to distinguish in remote data sets; (3) taking care to

  8. The Use of Handheld X-Ray Fluorescence (XRF) Technology in Unraveling the Eruptive History of the San Francisco Volcanic Field, Arizona

    Science.gov (United States)

    Young, Kelsey E.; Evans, C. A.; Hodges, K. V.

    2012-01-01

    While traditional geologic mapping includes the examination of structural relationships between rock units in the field, more advanced technology now enables us to simultaneously collect and combine analytical datasets with field observations. Information about tectonomagmatic processes can be gleaned from these combined data products. Historically, construction of multi-layered field maps that include sample data has been accomplished serially (first map and collect samples, analyze samples, combine data, and finally, readjust maps and conclusions about geologic history based on combined data sets). New instruments that can be used in the field, such as a handheld xray fluorescence (XRF) unit, are now available. Targeted use of such instruments enables geologists to collect preliminary geochemical data while in the field so that they can optimize scientific data return from each field traverse. Our study tests the application of this technology and projects the benefits gained by real-time geochemical data in the field. The integrated data set produces a richer geologic map and facilitates a stronger contextual picture for field geologists when collecting field observations and samples for future laboratory work. Real-time geochemical data on samples also provide valuable insight regarding sampling decisions by the field geologist

  9. Controls on volcanism at intraplate basaltic volcanic fields

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    van den Hove, Jackson C.; Van Otterloo, Jozua; Betts, Peter G.; Ailleres, Laurent; Cas, Ray A. F.

    2017-02-01

    A broad range of controlling mechanisms is described for intraplate basaltic volcanic fields (IBVFs) in the literature. These correspond with those relating to shallow tectonic processes and to deep mantle plumes. Accurate measurement of the physical parameters of intraplate volcanism is fundamental to gain an understanding of the controlling factors that influence the scale and location of a specific IBVF. Detailed volume and geochronology data are required for this; however, these are not available for many IBVFs. In this study the primary controls on magma genesis and transportation are established for the Pliocene-Recent Newer Volcanics Province (NVP) of south-eastern Australia as a case-study for one of such IBVF. The NVP is a large and spatio-temporally complex IBVF that has been described as either being related to a deep mantle plume, or upper mantle and crustal processes. We use innovative high resolution aeromagnetic and 3D modelling analysis, constrained by well-log data, to calculate its dimensions, volume and long-term eruptive flux. Our estimates suggest volcanic deposits cover an area of 23,100 ± 530 km2 and have a preserved dense rock equivalent of erupted volcanics of least 680 km3, and may have been as large as 900 km3. The long-term mean eruptive flux of the NVP is estimated between 0.15 and 0.20 km3/ka, which is relatively high compared with other IBVFs. Our comparison with other IBVFs shows eruptive fluxes vary up to two orders of magnitude within individual fields. Most examples where a range of eruptive flux is available for an IBVF show a correlation between eruptive flux and the rate of local tectonic processes, suggesting tectonic control. Limited age dating of the NVP has been used to suggest there were pulses in its eruptive flux, which are not resolvable using current data. These changes in eruptive flux are not directly relatable to the rate of any interpreted tectonic driver such as edge-driven convection. However, the NVP and other

  10. Using Spatial Density to Characterize Volcanic Fields on Mars

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    Richardson, J. A.; Bleacher, J. E.; Connor, C. B.; Connor, L. J.

    2012-01-01

    We introduce a new tool to planetary geology for quantifying the spatial arrangement of vent fields and volcanic provinces using non parametric kernel density estimation. Unlike parametricmethods where spatial density, and thus the spatial arrangement of volcanic vents, is simplified to fit a standard statistical distribution, non parametric methods offer more objective and data driven techniques to characterize volcanic vent fields. This method is applied to Syria Planum volcanic vent catalog data as well as catalog data for a vent field south of Pavonis Mons. The spatial densities are compared to terrestrial volcanic fields.

  11. Monogenetic volcanism in the Cordillera Central of Colombia: unknown volcanic fields associated with the northernmost Andes' volcanic chain related subduction

    Science.gov (United States)

    Murcia, Hugo; Borrero, Carlos; Németh, Károly

    2017-04-01

    Monogenetic volcanic fields are commonly related to rifts and/or intraplate tectonic settings. However, although less common, they appear also associated with subduction zones, including both front and back-arc volcanoes. To nourish this uncommon tectonic location, it is shown here that monogenetic volcanic fields, in addition to polygenetic volcanoes, also appear at the northernmost part of the Andes Northern Volcanic Zone (NVZ) (2° S to 4°30´N). These fields are associated with the main axe of the Quaternary active volcanic structures; they are linked to the polygenetic Cerro Bravo - Cerro Machín Volcanic Chain ( 80 km long; CBCMVC) in Colombia, the chain that hosts the iconic Nevado del Ruiz volcano. To the present, three monogenetic volcanic fields, with a typical calc-alkaline signature, have been identified in both sides of this chain: 1) Villamaría - Termales Monogenetic Volcanic Field (VTMVF) located to the northwestern part (>5 km) of the CBCMVC. This field is made up of at least 14 volcanoes aligned with the Villamaría - Termales fault zone. The volcanism has been mainly effusive, represented by lava domes and some lava flows. The volcanoes are andesitic to dacitic in composition. It is inferred that the magmatic source is a magma chamber close to Nevado del Ruiz volcano. Based on stratigraphic relationships, it is assumed that the last eruption occurred 10 wt.%) in the whole CBCMVC. Its source is related to the same magmas that feed the volcanoes in the CBCMVC. Stratigraphic relationships show that the volcanoes are younger than the underlying alluvial and volcaniclastic Ibagué fan (<1 Ma). Overall, it is clear that monogenetic volcanic fields are not atypical in the area, although their relationship with the magmatism feeding the polygenetic arc of the Andes' volcanic chain related subduction, is still unknown.

  12. The Zuni-Bandera Volcanic Field, NM: An Analog for Exploring Planetary Volcanic Terrains

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    Bleacher, J. E.; Garry, W. B.; Zimbelman, J. R.; Crumpler, L. S.; Aubele, J. C.

    2010-12-01

    The Zuni-Bandera volcanic field, near Grants, New Mexico, is comprised of volcanic deposits from several basaltic eruptions during the last million years. This vent field exhibits a diverse group of coalesced lava flows and displays well-preserved volcanic features including a’a and pahoehoe flows, collapsed lava tubes, cinder cones and low shields. The McCartys flow is a 48-km long inflated basalt flow and is the youngest in the field at around 3000 years old. Over the last three years we have used the Zuni-Bandera volcanic field, and the McCartys flow in particular, as a terrestrial analog for exploring planetary volcanic fields, and understanding the role of lava sheet inflation in flow field development. We have conducted three different styles of analog tests, 1) basic field science focused on understanding lava sheet inflation, 2) mission operations tests related to EVA design and real-time modification of traverse plans, and 3) science enabling technology tests. The Zuni-Bandera field is an ideal location for each style of analog test because it provides easy access to a diverse set of volcanic features with variable quality of preservation. However, many limitations must also be considered in order to maximize lessons learned. The McCartys flow displays well-preserved inflation plateaus that rise up to 15 m above the surrounding field. The preservation state enables textures and morphologies indicative of this process to be characterized. However, the pristine nature of the flow does not compare well with the much older and heavily modified inflated flows of Mars and the Moon. Older flows west of McCartys add value to this aspect of analog work because of their degraded surfaces, development of soil horizons, loose float, and limited exposure of outcrops, similar to what might be observed on the Moon or Mars. EVA design tests and science enabling technology tests at the Zuni-Bandera field provide the opportunity to document and interpret the relationships

  13. Explosive Volcanic Activity at Extreme Depths: Evidence from the Charles Darwin Volcanic Field, Cape Verdes

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    Kwasnitschka, T.; Devey, C. W.; Hansteen, T. H.; Freundt, A.; Kutterolf, S.

    2013-12-01

    Volcanic eruptions on the deep sea floor have traditionally been assumed to be non-explosive as the high-pressure environment should greatly inhibit steam-driven explosions. Nevertheless, occasional evidence both from (generally slow-) spreading axes and intraplate seamounts has hinted at explosive activity at large water depths. Here we present evidence from a submarine field of volcanic cones and pit craters called Charles Darwin Volcanic Field located at about 3600 m depth on the lower southwestern slope of the Cape Verdean Island of Santo Antão. We examined two of these submarine volcanic edifices (Tambor and Kolá), each featuring a pit crater of 1 km diameter, using photogrammetric reconstructions derived from ROV-based imaging followed by 3D quantification using a novel remote sensing workflow, aided by sampling. The measured and calculated parameters of physical volcanology derived from the 3D model allow us, for the first time, to make quantitative statements about volcanic processes on the deep seafloor similar to those generated from land-based field observations. Tambor cone, which is 2500 m wide and 250 m high, consists of dense, probably monogenetic medium to coarse-grained volcaniclastic and pyroclastic rocks that are highly fragmented, probably as a result of thermal and viscous granulation upon contact with seawater during several consecutive cycles of activity. Tangential joints in the outcrops indicate subsidence of the crater floor after primary emplacement. Kolá crater, which is 1000 m wide and 160 m deep, appears to have been excavated in the surrounding seafloor and shows stepwise sagging features interpreted as ring fractures on the inner flanks. Lithologically, it is made up of a complicated succession of highly fragmented deposits, including spheroidal juvenile lapilli, likely formed by spray granulation. It resembles a maar-type deposit found on land. The eruption apparently entrained blocks of MORB-type gabbroic country rocks with

  14. A Geochemical Investigation of Volcanic Rocks from the San Rafael Volcanic Field, Utah

    Science.gov (United States)

    Koebli, D. J.; Germa, A.; Connor, C.; Atlas, Z. D.

    2016-12-01

    A Geochemical Investigation of Volcanic Rocks from the San Rafael Volcanic Field, Utah Authors: Danielle Koebli, Dr. Aurelie Germa, Dr. Zackary Atlas, Dr. Charles Connor The San Rafael Volcanic Field (SRVF), Utah, is a 4Ma volcanic field located in the northwestern section of the Colorado Plateau. Alkaline magmas intruded into Jurassic sandstones , known as the Carmel, Entrada, Curtis and Summerville sandstone formations, and formed comagmatic dikes, sills and conduits that became uniquely well exposed as country rocks were eroded. The two rock types that formed from the melts are shonkinite (45.88 wt% SiO2) and syenite (50.84wt% SiO2); with dikes being predominantly shonkinite and sills exhibiting vertical alternation of shonkinite and syenite, a result of liquid immiscibility. The aim of this study is to determine magma temperatures, and mineral compositions which will be used for determining physical conditions for magma crystallization. Research is being conducted using an Electron Probe Micro Analyzer (EPMA) for single crystal analysis, and data were plotted using PINGU software through VHub cyberinfrastructure. EPMA data supports hydrated magma theories due to the large amounts of biotite and hornblende mixed in with olivine, feldspar and pyroxene. The data is also indicative of a calcium-rich magma which is further supported by the amount of pyroxene and plagioclase in the sample. Moreover, there are trace amounts orthoclase, quartz and k-feldspar due to sandstone inclusions from the magma intruding into the country rocks. The olivine crystals present in the samples are all chemically similar, having high Mg (Fo80-Fo90), which, coupled with a lower Fe content indicate a hotter magma. Comparison of mineral and whole-rock compositions using MELTs program will allow us to calculate magma viscosity and density so that the physical conditions for magma crystallization can be determined.

  15. Spatio-temporal evolution of the Tuxtla Volcanic Field

    Science.gov (United States)

    Kobs Nawotniak, S. E.; Espindola, J.; Godinez, L.

    2010-12-01

    Mapping of the Tuxtla Volcanic Field (TVF), located in Veracruz, Mexico, through the use of digital elevation models, aerial photography, and field confirmation has found 353 distinct cones, 4 large composite volcanoes, and 42 maars. Eruptive activity in the TVF began in the late Miocene, underwent a quiescent period approximately 2.6-0.8 Ma, and continues into historic times with the most recent eruption occurring at San Martín Tuxtla volcano in 1793. The covariance of the minimum cone separation in the TVF indicates that, despite the influence of clear vent alignments following regional faulting trends, the field as a whole is anticlustered. Dividing the cones by morphometric age shows that while the older cones have an anti-clustered distribution, the younger cones (Catemaco. These areas of concentrated volcanism roughly correspond to the locations of two gravity anomalies previously identified in the area. While the average height/width ratio is equal between the two clusters, the cones in the eastern group are significantly smaller than their counterparts in the western group. The maars of the TVF are mostly located within the younger volcanic series, west of Laguna Catemaco, and have an anticlustered distribution; many of the maars are evenly spaced along curved lines, where they are weakly grouped according to crater diameter. Results indicate volcanism TVF has undergone continued spatial restriction over time, concentrating in the western half of the TVF with the onset of the eruption of the younger volcanic series 0.8 Ma and further contracting along the principle fault system within the last 50 Ka.

  16. Palaeointensity of the Plio-Pleistocene Boring Volcanic Field

    Science.gov (United States)

    Lhuillier, Florian; Shcherbakov, Valeriy; Gilder, Stuart A.; Hagstrum, Jonathan T.

    2017-04-01

    The Boring Volcanic Field of the Pacific Northwest, USA, consists of more than 80 eruptive units ranging in age from 3200 to 60 ka. We carried out in this study absolute (Wilson + Thellier-Coe) and relative (pseudo-Thellier) palaeointensity experiments. We managed to determine robust palaeointensity estimates for 12 independent cooling units, whereas the pseudo-Thellier analysis yielded estimates for 47 out of the 137 investigated sites, giving an insight into the relative variability of the Earth's magnetic field during this period. We would like to compare the present results with the existing database for the last 3 myr and discuss their implications in terms of geodynamo process. From a methodological point of view, we would also like to comment on the reliability of the pseudo-Thellier method on volcanic rocks.

  17. Field guide to geologic excursions in southwestern Utah and adjacent areas of Arizona and Nevada

    Science.gov (United States)

    Lund, William R.; Lund, William R.

    2002-01-01

    This field guide contains road logs for field trips planned in conjunction with the 2002 Rocky Mountain Section meeting of the Geological Society of America held at Southern Utah University in Cedar City, Utah. There are a total of eight field trips, covering various locations and topics in southwestern Utah and adjacent areas of Arizona and Nevada. In addition, the field guide contains a road log for a set of Geological Engineering Field Camp Exercises run annually by the University of Missouri at Rolla in and around Cedar City. Two of the field trips address structural aspects of the geology in southwestern Utah and northwestern Arizona; two trips deal with ground water in the region; and along with the Field Camp Exercises, one trip, to the Grand Staircase, is designed specifically for educators. The remaining trips examine the volcanology and mineral resources of a large area in and around the Tusher Mountains in Utah; marine and brackish water strata in the Grand Staircase-Escalante National Monument; and the Pine Valley Mountains, which are cored by what may be the largest known laccolith in the world. The "Three Corners" area of Utah, Arizona, and Nevada is home to truly world-class geology, and I am confident that all of the 2002 Rocky Mountain Section meeting attendees will find a field trip suited to their interests.

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

    Science.gov (United States)

    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.

  19. Diffraction-limited Mid-infrared Integral Field Spectroscopy of Io's Volcanic Activity with ALES on the Large Binocular Telescope

    Science.gov (United States)

    Skrutskie, Michael F.; de Kleer, Katherine R.; Stone, Jordan; Conrad, Al; Davies, Ashley; de Pater, Imke; Leisenring, Jarron; Hinz, Philip; Skemer, Andrew; Veillet, Christian; Woodward, Charles E.; Ertel, Steve; Spalding, Eckhart

    2017-10-01

    The Arizona Lenslet for Exoplanet Spectroscopy (ALES) is an enhancement to the Large Binocular Telescope's mid-infrared imager, LMIRcam, that permits low-resolution (R~20) spectroscopy between 2.8 and 4.2 μm of every diffraction-limited resolution element in a 2.5"x2.5" field-of-view on a 2048x2048 HAWAII-2RG 5.2 μm-cutoff array. The 1" disk of Io, dotted with powerful self-luminous volcanic eruptions, provides an ideal target for ALES, where the single 8.4-meter aperture diffraction-limited scale for Io at opposition ranges from 240 kilometers (80 milliarcseconds) at 2.8 μm to 360 kilometers (120 milliarcseconds) at 4.2 μm. ALES provides the capability to assess the color temperature of each volcanic thermal emission site as well as map broadband absorbers such as SO2 frost. A monitoring campaign in the Spring 2017 semester provided two global snapshots of Io's volcanic activity with ALES as well as characterization of a new brightening episode at Loki Patera over four epochs between January and May 2017.

  20. Seismic signals at the Nirano Mud Volcanic Field, Italy

    Science.gov (United States)

    Antunes, Verónica; Lupi, Matteo; Carrier, Aurore; Planès, Thomas; Obermann, Anne; Mazzini, Adriano; Ricci, Tullio; Sciarra, Alessandra; Moretti, Milena

    2017-04-01

    Mud volcanoes are geological phenomena that only recently are beginning to be investigated with passive seismic methods. To shed light on the seismic signals associated with mud volcanic activity we deployed a temporary network composed of 7 seismic stations around Nirano, Italy. We identified the different types of signals generated by this active system. During the three months survey period, the stations repeatedly recorded drumbeat signals beneath the structure. We have identified two types of drumbeat signals: one with durations of about 50 seconds and frequency range of 10-45 Hz; the second has a duration of about 4 seconds and frequency range of 5-45 Hz. These drumbeat signals were captured depending on the position of the seismic station and the distance from the mud vents. We also identified a third signal, present in almost every station in the network, with a duration of about 10 seconds and frequency range of 5-45 Hz. The amplitude of these signals varies across the stations suggesting that the most active part of the system is located in the north eastern-most area of the mud volcanic field where new mud vents recently appeared.

  1. Morphometric characterization of monogenetic volcanic cones of the Chichinautzin and Michoacán-Guanajuato monogenetic volcanic fields in Mexico

    Science.gov (United States)

    Zarazua-Carbajal, Maria Cristina; De la Cruz-Reyna, Servando; Mendoza-Rosas, Ana Teresa

    2014-05-01

    Morphometric characterization of volcanic edifices is one of the main approaches providing information about a volcano eruptive history, whether it has one or more eruptive vents or if it had any sector collapses. It also provides essential information about the physical processes that modify their shapes during periods of quietness, and quite significantly, about the volcanoes' ages. In the case of monogenetic activity, a volcanic field can be characterized by the size and slope distributions, and other cone's morphometric parameter distributions that may provide valuable information about the temporal evolution of the volcanic field. The increasingly available high-resolution digital elevation models and the continuously developing computer tools have allowed a faster development and more detailed morphometric characterization techniques. We present here a methodology to readily obtain diverse volcanic cone shape parameters from the contour curves such as mean slope, slope distribution, dimensions of the cone and crater, crater location within the cone, orientation of the cone's principal axis, eccentricity, and other morphological features using an analysis algorithm that we developed, programmed in Python and ArcPy. Preliminary results from the implementation of this methodology to the Chichinautzin and Michoacán-Guanajuato monogenetic volcanic fields in Mexico have permitted a preliminary estimation of the age distribution of some of the cones with an acceptable correlation with the available radiometric ages. A large part of the Chichinautzin region DEM was obtained from a LIDAR survey by the Mexican National Institute of Statistics and Geography (INEGI).

  2. Magmatic Evolution in the Los Tuxtlas Volcanic Field, Veracruz, Mexico

    Science.gov (United States)

    Koster, A.; Kobs-Nawotniak, S. E.

    2012-12-01

    Magma evolution within the Los Tuxtlas Volcanic Field (LTVF) is poorly understood. The LTVF is a basaltic, monogenetic field in Veracruz, Mexico, that contains approximately 400 vents and has been active for the last 7 Ma, including a sub-Plinian eruption in 1793. The field is structurally controlled, with cones forming NW-SE lines consistent with local extension. By understanding magmatic evolution through ascent, storage, and mixing, it is possible to more accurately predict future trends in the system. Samples from two alignments of cinder cones located between San Martin Tuxtlas volcano and Laguna Catemaco were analyzed petrographically and geochemically. Geochemical data were plotted in Fenner and Harker diagrams to identify trends, including fractional crystallization and magma recharge. Mineral modes were calculated via point counting in thin sections, and micro-textural variations were noted. Cone morphometry was used as a rough proxy for age along with field relationships to develop an approximate order of events along the alignments. Preliminary data suggest that the aligned vents are part of a linked magmatic plumbing system undergoing periodic recharge.

  3. Constraining volcanic inflation at Three Sisters Volcanic Field in Oregon, USA, through microgravity and deformation modeling

    Science.gov (United States)

    Zurek, Jeffrey; William-Jones, Glyn; Johnson, Dan; Eggers, Al

    2012-10-01

    Microgravity data were collected between 2002 and 2009 at the Three Sisters Volcanic Complex, Oregon, to investigate the causes of an ongoing deformation event west of South Sister volcano. Three different conceptual models have been proposed as the causal mechanism for the deformation event: (1) hydraulic uplift due to continual injection of magma at depth, (2) pressurization of hydrothermal systems and (3) viscoelastic response to an initial pressurization at depth. The gravitational effect of continual magma injection was modeled to be 20 to 33 μGal at the center of the deformation field with volumes based on previous deformation studies. The gravity time series, however, did not detect a mass increase suggesting that a viscoelactic response of the crust is the most likely cause for the deformation from 2002 to 2009. The crust, deeper than 3 km, in the Three Sisters region was modeled as a Maxwell viscoelastic material and the results suggest a dynamic viscosity between 1018 to 5 × 1019 Pa s. This low crustal viscosity suggests that magma emplacement or stall depth is controlled by density and not the brittle ductile transition zone. Furthermore, these crustal properties and the observed geochemical composition gaps at Three Sisters can be best explained by different melt sources and limited magma mixing rather than fractional crystallization. More generally, low intrusion rates, low crustal viscosity, and multiple melt sources could also explain the whole rock compositional gaps observed at other arc volcanoes.

  4. The Satah Mountain and Baldface Mountain volcanic fields: Pleistocene hot spot volcanism in the Anahim Volcanic Belt, west-central British Columbia, Canada

    Science.gov (United States)

    Kuehn, Christian; Guest, Bernard; Russell, James K.; Benowitz, Jeff A.

    2015-03-01

    The Satah Mountain and Baldface Mountain volcanic fields (SMVF, BMVF) comprise more than three dozen small volcanic centers and erosional remnants thereof. These fields are located in the Chilcotin Highland of west-central British Columbia, Canada, and are spatially associated with the Anahim Volcanic Belt (AVB), a linear feature of alkaline to peralkaline plutonic and volcanic centers of Miocene to Holocene ages. The AVB has been postulated to be the track of a hot spot passing beneath the westward moving Cordilleran lithosphere. We test the AVB hot spot model by applying whole-rock 40Ar/39Ar geochronology ( n = 24) and geochemistry. Whole-rock chemical compositions of volcanic rock samples ( n = 59) from these two fields suggest a strong geochemical affinity with the nearby Itcha Range shield volcano; however, SMVF and BMVF centers are mostly small in volume (<1 km3) and differ in composition from one another, even where they are in close spatial proximity. Trace element and REE patterns of mafic AVB lavas are similar to ocean island basalts (OIB), suggesting a mantle source for these lavas. The age ranges for the SMVF ( n = 11; ~2.21 to ~1.43 Ma) and BMVF ( n = 7; ~3.91 to ~0.91 Ma) are largely coeval with the Itcha Range. The distribution of volcanoes in these two volcanic fields is potentially consistent with the postulated AVB hot spot track. Eruption rates in the SMVF were high enough to build an elongated ridge that deviates from the E-W trend of the AVB by almost 90°. This deviation might reflect the mechanisms and processes facilitating magma generation and ascent through the lithosphere in this tectonically complex region and may also indicate interaction of the potential hot spot with (pre)existing fracture systems in vicinity of the Itcha Range.

  5. Geothermal Fields on the Volcanic Axis of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Mercado, S.; Gonzalez, A.

    1980-12-16

    At present in Mexico, geothermal energy is receiving a great impulse due to the excellent results obtained in the Cerro Prieto geothermal field, in which a geothermoelectric plant is operated. This plant has four units of 37.5 MW each, with a total capacity of 150 MW, and under program 470 MW more by 1984. The Government Institution, Comisi6n Federal de Electricidad, is in charge of the exploration and exploitation of geothermal fields as well as construction and operation of power plants in Mexico. By this time CFE has an extensive program of exploration in the central part of Mexico, in the Eje Neovolcdnico. In this area, several fields with hydrothermal alteration are under exploration, like the Michoac6n geothermal area, where Los Azufres geothermal field is being developed. Seventeen wells have been drilled and twelve of them presented excellent results, including two dry steam wells. In other areas, such as Arar6, Cuitzeo, San Agustln del Maiz,Ixtldn de Los Hervores and Los Negritos, geological, geophysical and geochemical explorations have been accomplished, including shallow well drilling with good results. Another main geothermal area is in the State of Jalisco with an extension of 5,000 m2, where La Primavera geothermal field shows a lot of volcanic domes and has an intensive hydrothermal activity. Deep wells have been drilled, one of them with a bottom temperature of 29OOC. Other fields in this area, like San Narcos, Hervores de La Vega, La Soledad, Villa Corona, etc., have a good geothermal potential. A new geothermal area has been explored recently in the eastern part of the country named Los Humeros, Puebla. In this area studies are being made and there are plans for well drilling exploration by the beginning of 1981. Like this one, there are many other areas in the country in which 300 hydrothermal alteration zones are been classified and 100 of them are considered economically exploitable.

  6. Vegetation and substrate properties of aeolian dune fields in the Colorado River corridor, Grand Canyon, Arizona

    Science.gov (United States)

    Draut, Amy E.

    2011-01-01

    This report summarizes vegetation and substrate properties of aeolian landscapes in the Colorado River corridor through Grand Canyon, Arizona, in Grand Canyon National Park. Characterizing these parameters provides a basis from which to assess future changes in this ecosystem, including the spread of nonnative plant species. Differences are apparent between aeolian dune fields that are downwind of where modern controlled flooding deposits new sandbars (modern-fluvial-sourced dune fields) and those that have received little or no new windblown sand since river regulation began in the 1960s (relict-fluvial-sourced dune fields). The most substantial difference between modern- and relict-fluvial-sourced aeolian dune fields is the greater abundance of biologic soil crust in relict dune fields. These findings can be used with similar investigations in other geomorphic settings in Grand Canyon and elsewhere in the Colorado River corridor to evaluate the health of the Colorado River ecosystem over time.

  7. Ancient Mudflows in the Tuxtla Volcanic Field, Veracruz, Mexico

    Science.gov (United States)

    Espindola, J.; Zamora-Camacho, A.; Godinez, M.

    2011-12-01

    The Tuxtla Volcanic Field (TVF) is a basaltic volcanic enclave in eastern Mexico at the margin of the Gulf of Mexico. Due to the high rates of precipitation floods and mudflows are common. Resulting from a systematic study of geologic hazard in the TVF we found several mudflow deposits that impacted pre-Columbian settlements. Sections of the deposits were observed in detail and sampled for granulometric studies. The deposits contained materials suitable for dating: ceramic shards and some of them charcoal fragments. Shards from the interior of the deposit were collected and placed in black bags to prevent the action of light and to be analyzed by thermoluminiscense (TL), the charcoal samples were dated using standard radiocarbon methods (C-14). The sites were dubbed La Mojarra (18°37.711', 95°18.860'), Revolución (18° 35.848', 95°11.412'), Pisatal (18°36.618', 95°10.634'), and Toro Prieto (18°38.229, 95°12.037'). These places were named after the nearby villages the first two, lake Pisatal the third and Toro Prieto creek the fourth. All the deposits occur close to the margins of riverbeds or lakes. Samples of these sites yielded ages of 1176±100 (TL), 1385±70 (C-14), 1157±105 (TL), 2050+245-235 (C-14), respectively. These locations have undergone recurrent floods in the last decades, showing that these phenomena impact the same areas over centuries. The dates mentioned are important because, no vestiges of human settlements had been reported in the area, which in the past was covered by a dense forest. The settlements must have been very small and depended of such cities as nearby Matacapan an important city with strong ties to Teotihuacán in central Mexico. The ages agree with the findings of archeologic studies in Matacapan, which indicate that the population became increasingly ruralized since the late classic period (≈ 600-800 AD).

  8. Timing and development of the Heise volcanic field, Snake River Plain, Idaho, western USA

    Science.gov (United States)

    Morgan, L.A.; McIntosh, W.C.

    2005-01-01

    The Snake River Plain (SRP) developed over the last 16 Ma as a bimodal volcanic province in response to the southwest movement of the North American plate over a fixed melting anomaly. Volcanism along the SRP is dominated by eruptions of explosive high-silica rhyolites and represents some of the largest eruptions known. Basaltic eruptions represent the final stages of volcanism, forming a thin cap above voluminous rhyolitic deposits. Volcanism progressed, generally from west to east, along the plain episodically in successive volcanic fields comprised of nested caldera complexes with major caldera-forming eruptions within a particular field separated by ca. 0.5-1 Ma, similar to, and in continuation with, the present-day Yellowstone Plateau volcanic field. Passage of the North American plate over the melting anomaly at a particular point in time and space was accompanied by uplift, regional tectonism, massive explosive eruptions, and caldera subsidence, and followed by basaltic volcanism and general subsidence. The Heise volcan ic field in the eastern SRP, Idaho, represents an adjacent and slightly older field immediately to the southwest of the Yellowstone Plateau volcanic field. Five large-volume (>0.5 km3) rhyolitic ignimbrites constitute a time-stratigraphic framework of late Miocene to early Pliocene volcanism for the study region. Field relations and high-precision 40Ar/39Ar age determinations establish that four of these regional ignimbrites were erupted from the Heise volcanic field and form the framework of the Heise Group. These are the Blacktail Creek Tuff (6.62 ?? 0.03 Ma), Walcott Tuff (6.27 ?? 0.04 Ma), Conant Creek Tuff (5.51 ?? 0.13 Ma), and Kilgore Tuff (4.45 ?? 0.05 Ma; all errors reported at ?? 2??). The fifth widespread ignimbrite in the regions is the Arbon Valley Tuff Member of the Starlight Formation (10.21 ?? 0.03 Ma), which erupted from a caldera source outside of the Heise volcanic field. These results establish the Conant Creek Tuff as a

  9. Oxygen Isotope Character of the Lake Owyhee Volcanic Field, Oregon

    Science.gov (United States)

    Blum, T.; Strickland, A.; Valley, J. W.

    2012-12-01

    Oxygen isotope analyses of zircons from lavas and tuffs from the Lake Owyhee Volcanic Field (LOVF) of east central Oregon unequivocally demonstrate the presence of mid-Miocene low-δ18O magmas (δ18Ozrcperalkaline to metaluminous rhyolitic lavas and ignimbrites erupted from a series of fissures and calderas. Geographically, the LOVF overlaps the Oregon-Idaho Graben (OIG), and straddles the 87Sr/86Sr= 0.704 line which, together with the 0.706 line to the east, delineate the regional transition from the North American Precambrian continental crust to the east to younger Phanerozoic accreted terranes to the west. Here we report high accuracy ion microprobe analyses of δ18O in zircons using a 10-15μm spot, with average spot-to-spot precision ±0.28‰ (2SD), to investigate intra-grain and intra-unit δ18Ozrc trends for LOVF rhyolites. Due to its high closure temperature, chemical and physical resistance, and slow oxygen diffusion rates, zircon offers a robust record of magmatic oxygen isotope ratios during crystallization and provides constraints on the petrogenesis of Snake River Plain (SRP) low-δ18O melts. Individual zircons from LOVF rhyolites show no evidence of core-rim δ18O zoning, and populations exhibit ≤0.42‰ (2SD) intra-unit variability. Unit averages range from 2.2 to 4.3‰, with the lowest values in caldera-forming ignimbrites, but all units show evidence of crystallization from low-δ18O melts. Quartz and feldspar analyses by laser fluorination (precision ±0.20‰, 2SD) indicate δ18Oqtz ranges between 5.7 and 6.8‰, and δ18OKfs between -5.4 and +6.7‰. Δ18O(qtz-zrc) ranges from 2.1-2.5‰, while Δ18O(Kfs-zrc) varies from 2.3 to -7.7‰. Quartz values are consistent with equilibration at magmatic temperatures, however, at least some feldspars have undergone subsolidus exchange and feldspar or whole rock δ18O values are not reliably igneous. The observed low-δ18Ozrc values document high temperature interaction of magmatic protoliths with

  10. The Western Arabian intracontinental volcanic fields as a potential UNESCO World Heritage site

    Science.gov (United States)

    Németh, Károly; Moufti, Mohammed R.

    2017-04-01

    UNESCO promotes conservation of the geological and geomoprhological heritage through promotion of protection of these sites and development of educational programs under the umbrella of geoparks among the most globally significant ones labelled as UNESCO Global Geoparks. UNESCO also maintains a call to list those natural sites that provide universal outstanding values to demonstrate geological features or their relevance to our understanding the evolution of Earth. Volcanoes currently got a surge in nomination to be UNESCO World Heritage sites. Volcanic fields in the contrary fell in a grey area of nominations as they represents the most common manifestation of volcanism on Earth hence they are difficult to view as having outstanding universal values. A nearly 2500-km long 300-km wide region of dispersed volcanoes located in the Western Arabian Penninsula mostly in the Kingdom of Saudi Arabia form a near-continuous location that carries universal outstanding value as one of the most representative manifestation of dispersed intracontinental volcanism on Earth to be nominated as an UNESCO World Heritage site. The volcanic fields formed in the last 20 Ma along the Red Sea as group of simple basaltic to more mature and long-lived basalt to trachyte-to-rhyolite volcanic fields each carries high geoheritage values. While these volcanic fields are dominated by scoria and spatter cones and transitional lava fields, there are phreatomagmatic volcanoes among them such as maars and tuff rings. Phreatomagmatism is more evident in association with small volcanic edifices that were fed by primitive magmas, while phreatomagmatic influences during the course of a larger volume eruption are also known in association with the silicic eruptive centres in the harrats of Rahat, Kishb and Khaybar. Three of the volcanic fields are clearly bimodal and host small-volume relatively short-lived lava domes and associated block-and-ash fans providing a unique volcanic landscape commonly not

  11. The polycyclic Lausche Volcano (Lausitz Volcanic Field) and its message\

    Czech Academy of Sciences Publication Activity Database

    Wenger, E.; Büchner, J.; Tietz, O.; Mrlina, Jan

    2017-01-01

    Roč. 292, September (2017), s. 193-210 ISSN 0169-555X Institutional support: RVO:67985530 Keywords : Lausche * polycyclic volcanism * Lausitz Overthrust (Lusatian Fault) * North Bohemian-Saxonian Cretaceous Basin Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.958, year: 2016

  12. A newly discovered Pliocene volcanic field on the western Sardinia continental margin (western Mediterranean)

    Science.gov (United States)

    Conforti, Alessandro; Budillon, Francesca; Tonielli, Renato; De Falco, Giovanni

    2016-02-01

    A previously unknown submerged volcanic field offshore western Sardinia (western Mediterranean Sea), has been identified based on swath bathymetric data collected in 2009, 2010 and 2013, and high-resolution seismic profiles collected in 2011 and 2013. About 40 conical-shaped volcanic edifices (maximum width of about 1600 m and maximum height of about 180 m) and several lava outcrops (up to 1,200 m wide) were recognized at 20 to 150 m water depth over an area of 800 km2. The volcanic edifices are mainly eruptive monogenic vents, mostly isolated with a rather distinct shape, or grouped to form a coalescent volcanic body in which single elements are often still recognizable. High-resolution seismics enabled identifying relationships between the volcanic bodies and continental margin successions. The edifices overlie a major erosional surface related to the margin exposure following the Messinian salinity crisis, and are overlain by or interbedded with an early Pliocene marine unit. This seismo-stratigraphic pattern dates the volcanic activity to the early Pliocene, in agreement with the radiometric age of the Catalano island lavas (4.7 Ma) reported in earlier studies. The morphometry of the volcanic bodies suggests that cone erosion was higher at shallow water depths. Indeed, most of the shallow edifices are strongly eroded and flattened at 125 to 130 m water depth, plausibly explained by recurrent sub-aerial exposure during Pleistocene sea-level lowstands, whereas cones in deeper water are much better preserved. Volcanic vents and lava deposits, hereafter named the Catalano volcanic field (CVF), are emplaced along lineaments corresponding to the main directions of the normal fault system, which lowered the Sinis Basin and the western Sardinia continental margin. The CVF represents a volumetrically relevant phase of the late Miocene - Quaternary anorogenic volcanic cycle of Sardinia, which is related to the first stage of the extensional tectonics affecting the island

  13. The Boring Volcanic Field of the Portland-Vancouver area, Oregon and Washington: tectonically anomalous forearc volcanism in an urban setting

    Science.gov (United States)

    Evarts, Russell C.; Conrey, Richard M.; Fleck, Robert J.; Hagstrum, Jonathan T.; O'Connor, Jim; Dorsey, Rebecca; Madin, Ian P.

    2009-01-01

    More than 80 small volcanoes are scattered throughout the Portland-Vancouver metropolitan area of northwestern Oregon and southwestern Washington. These volcanoes constitute the Boring Volcanic Field, which is centered in the Neogene Portland Basin and merges to the east with coeval volcanic centers of the High Cascade volcanic arc. Although the character of volcanic activity is typical of many monogenetic volcanic fields, its tectonic setting is not, being located in the forearc of the Cascadia subduction system well trenchward of the volcanic-arc axis. The history and petrology of this anomalous volcanic field have been elucidated by a comprehensive program of geologic mapping, geochemistry, 40Ar/39Ar geochronology, and paleomag-netic studies. Volcanism began at 2.6 Ma with eruption of low-K tholeiite and related lavas in the southern part of the Portland Basin. At 1.6 Ma, following a hiatus of ~0.8 m.y., similar lavas erupted a few kilometers to the north, after which volcanism became widely dispersed, compositionally variable, and more or less continuous, with an average recurrence interval of 15,000 yr. The youngest centers, 50–130 ka, are found in the northern part of the field. Boring centers are generally monogenetic and mafic but a few larger edifices, ranging from basalt to low-SiO2 andesite, were also constructed. Low-K to high-K calc-alkaline compositions similar to those of the nearby volcanic arc dominate the field, but many centers erupted magmas that exhibit little influence of fluids derived from the subducting slab. The timing and compositional characteristics of Boring volcanism suggest a genetic relationship with late Neogene intra-arc rifting.

  14. Geology and geochemistry of volcanic centers within the eastern half of the Sonoma volcanic field, northern San Francisco Bay region, California

    Science.gov (United States)

    Sweetkind, Donald S.; Rytuba, James J.; Langenheim, V.E.; Fleck, Robert J.

    2011-01-01

    Volcanic rocks in the Sonoma volcanic field in the northern California Coast Ranges contain heterogeneous assemblages of a variety of compositionally diverse volcanic rocks. We have used field mapping, new and existing age determinations, and 343 new major and trace element analyses of whole-rock samples from lavas and tuff to define for the first time volcanic source areas for many parts of the Sonoma volcanic field. Geophysical data and models have helped to define the thickness of the volcanic pile and the location of caldera structures. Volcanic rocks of the Sonoma volcanic field show a broad range in eruptive style that is spatially variable and specific to an individual eruptive center. Major, minor, and trace-element geochemical data for intracaldera and outflow tuffs and their distal fall equivalents suggest caldera-related sources for the Pinole and Lawlor Tuffs in southern Napa Valley and for the tuff of Franz Valley in northern Napa Valley. Stratigraphic correlations based on similarity in eruptive sequence and style coupled with geochemical data allow an estimate of 30 km of right-lateral offset across the West Napa-Carneros fault zones since ~5 Ma.

  15. Development of a risk assessment tool for volcanic urban environments: RiskScape and the Auckland Volcanic Field, New Zealand

    Science.gov (United States)

    Deligne, N. I.; Leonard, G.; King, A.; Wilson, G.; Wilson, T.; Lindsay, J. M.

    2013-12-01

    Auckland city, home to a third of New Zealand's population, is situated on top of the Auckland Volcanic Field (AVF), which last erupted roughly 500 years ago. Since 2008, the Determining Volcanic Risk in Auckland (DEVORA) program has investigated the geologic context of the AVF, improved timing constraints of past eruptions, explored possible tempo-spatial-volume eruption trends, and identified likely styles and hazards of future eruptions. DEVORA is now moving into development of risk and societal models for Auckland. The volcanic module of RiskScape, a multi-hazard risk assessment tool developed by Crown Research Institutes GNS Science and NIWA, will be expanded and used to model risk and impact to the built environment and population caused by a future AVF eruption. RiskScape models casualties, damage and disruption caused by various hazards, the resulting reduced functionality of assets, and associated clean up costs. A strength of RiskScape is that the effect of various mitigation strategies can be explored by strengthening asset attributes and examining resulting changes in the output risk evaluation. We present our framework for building a volcano hazard exposure module for RiskScape along with our approach for assessing asset vulnerability through the development of fragility functions. We also present the framework for engagement with regional Auckland stakeholders, including representatives of local and regional governments and utility companies, to identify complementary needs to ensure that final risk products are relevant and useable by end users.

  16. The Eruptive History of the Talpa-Mascota-San Sebastian Volcanic Field in Western Mexico.

    Science.gov (United States)

    Ownby, S.; Lange, R.; Carmichael, I. S.; Hall, C.

    2004-12-01

    The eruptive history of the Talpa-Mascota-San Sebastian (TMSS) volcanic field in the Jalisco Block (JB) of western Mexico is presented. The JB is bounded by the Tepic-Zacoalco and Colima grabens, as well as the Middle America Trench where the Rivera plate subducts beneath North America. The TMSS volcanic field spans ˜2030 km2 and contains ˜123 small cones and flows of minette, absarokite, basic hornblende lamprophyre, basaltic andesite, and andesite. The petrology of these lavas is described in Lange and Carmichael (1990, 1991) and Carmichael et al. (1996). Of the ˜123 distinguishable eruptive units within this volcanic field, 26 samples have been dated by the 40Ar/39Ar method, and are combined with 10 dates from a previous abstract and nine dates from the literature (for a total of 45). The oldest lavas (2.35 to 0.5 Ma) are found in the Talpa region, whereas the youngest lavas (predominantly Mexico. These age results confirm that the potassic lavas of Mascota (not unlike those erupted 3-4 Myr ago in the Sierra Nevada batholith; Farmer et al., 2002) are part of line of similar volcanism that youngs to the N-NW. The Los Volcanes field was active from 3.4-1.5 Myr ago (Wallace and Carmichael, 1992), whereas two dates from the Ayutla volcanic field give ages of 4.4 and 4.5 Ma (Righter and Rosas-Elguera, 2001). It thus appears that this line of potassic volcanism within the interior of the Jalisco block is not a coeval "volcanic front", which raises the possibility that it may not be directly related to active subduction of the Rivera plate.

  17. Field-trip guides to selected volcanoes and volcanic landscapes of the western United States

    Science.gov (United States)

    ,

    2017-06-23

    The North American Cordillera is home to a greater diversity of volcanic provinces than any comparably sized region in the world. The interplay between changing plate-margin interactions, tectonic complexity, intra-crustal magma differentiation, and mantle melting have resulted in a wealth of volcanic landscapes.  Field trips in this guide book collection (published as USGS Scientific Investigations Report 2017–5022) visit many of these landscapes, including (1) active subduction-related arc volcanoes in the Cascade Range; (2) flood basalts of the Columbia Plateau; (3) bimodal volcanism of the Snake River Plain-Yellowstone volcanic system; (4) some of the world’s largest known ignimbrites from southern Utah, central Colorado, and northern Nevada; (5) extension-related volcanism in the Rio Grande Rift and Basin and Range Province; and (6) the eastern Sierra Nevada featuring Long Valley Caldera and the iconic Bishop Tuff.  Some of the field trips focus on volcanic eruptive and emplacement processes, calling attention to the fact that the western United States provides opportunities to examine a wide range of volcanological phenomena at many scales.The 2017 Scientific Assembly of the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) in Portland, Oregon, was the impetus to update field guides for many of the volcanoes in the Cascades Arc, as well as publish new guides for numerous volcanic provinces and features of the North American Cordillera. This collection of guidebooks summarizes decades of advances in understanding of magmatic and tectonic processes of volcanic western North America. These field guides are intended for future generations of scientists and the general public as introductions to these fascinating areas; the hope is that the general public will be enticed toward further exploration and that scientists will pursue further field-based research.

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

    Science.gov (United States)

    Hildreth, Wes; Fierstein, Judy

    2015-01-01

    Mountainous parts of the Yakama Nation lands in south-central Washington are mostly covered by basaltic lava flows and cinder cones that make up the Simcoe Mountains volcanic field. The accompanying geologic map of the central part of the volcanic field has been produced by the U.S. Geological Survey (USGS) on behalf of the Water Resources Program of the Yakama Nation. The volcanic terrain stretches continuously from Mount Adams eastward as far as Satus Pass and Mill Creek Guard Station. Most of the many hills and buttes are volcanic cones where cinders and spatter piled up around erupting vents while lava flows spread downslope. All of these small volcanoes are now extinct, and, even during their active lifetimes, most of them erupted for no more than a few years. On the Yakama Nation lands, the only large long-lived volcano capable of erupting again in the future is Mount Adams, on the western boundary.

  19. Paleomagnetism of the Pleistocene Tequila Volcanic Field (Western Mexico)

    Science.gov (United States)

    Rodríguez Ceja, M.; Goguitchaichvili, A.; Calvo-Rathert, M.; Morales-Contreras, J.; Alva-Valdivia, L.; Rosas Elguera, J.; Urrutia Fucugauchi, J.; Delgado Granados, H.

    2006-10-01

    This paper presents new paleomagnetic results from 24 independent cooling units in Tequila area (western Trans-Mexican Volcanic Belt). These units were recently dated by means of state-of-the-art 40Ar-39Ar method (Lewis-Kenedy et al., 2005) and span from 1130 to 150 ka. The characteristic paleodirections are successfully isolated for 20 cooling units. The mean paleodirection, discarding intermediate polarity sites, is I = 29.6°, D = 359.2°, k = 26, α95 = 7.1°, n = 17, which corresponds to the mean paleomagnetic pole position Plat = 85.8°, Plong = 84.3°, K = 27.5, A95 = 6.9°. These directions are practically undistinguishable from the expected Plestocene paleodirections, as derived from reference poles for the North American polar wander curve and in agreement with previously reported directions from western Trans-Mexican Volcanic Belt. This suggests that no major tectonic deformation occurred in studied area since early-middle Plestocene to present. The paleosecular variation is estimated trough the study of the scatter of virtual geomagnetic poles giving SF = 15.4 with SU = 19.9 and SL = 12.5 (upper and lower limits respectively). These values are consistent with those predicted by the latitude-dependent variation model of McFadden et al. (1991) for the last 5 Myr. The interesting feature of the paleomagnetic record obtained here is the occurrence of an intermediate polarity at 671± 13 ka which may correspond the worldwide observed Delta excursion at about 680-690 ka. This gives the volcanic evidence of this event. Two independent lava flows dated as 362± 13 and 354± 5 ka respectively, yield transitional paleodirections as well, probably corresponding to the Levantine excursion.

  20. Geologic field-trip guide to the volcanic and hydrothermal landscape of the Yellowstone Plateau

    Science.gov (United States)

    Morgan Morzel, Lisa Ann; Shanks, W. C. Pat; Lowenstern, Jacob B.; Farrell, Jamie M.; Robinson, Joel E.

    2017-11-20

    Yellowstone National Park, a nearly 9,000 km2 (~3,468 mi2) area, was preserved in 1872 as the world’s first national park for its unique, extraordinary, and magnificent natural features. Rimmed by a crescent of older mountainous terrain, Yellowstone National Park has at its core the Quaternary Yellowstone Plateau, an undulating landscape shaped by forces of late Cenozoic explosive and effusive volcanism, on-going tectonism, glaciation, and hydrothermal activity. The Yellowstone Caldera is the centerpiece of the Yellowstone Plateau. The Yellowstone Plateau lies at the most northeastern front of the 17-Ma Yellowstone hot spot track, one of the few places on Earth where time-transgressive processes on continental crust can be observed in the volcanic and tectonic (faulting and uplift) record at the rate and direction predicted by plate motion. Over six days, this field trip presents an intensive overview into volcanism, tectonism, and hydrothermal activity on the Yellowstone Plateau (fig. 1). Field stops are linked directly to conceptual models related to monitoring of the various volcanic, geochemical, hydrothermal, and tectonic aspects of the greater Yellowstone system. Recent interest in young and possible future volcanism at Yellowstone as well as new discoveries and synthesis of previous studies, (for example, tomographic, deformation, gas, aeromagnetic, bathymetric, and seismic surveys), provide a framework in which to discuss volcanic, hydrothermal, and seismic activity in this dynamic region.

  1. Volcanic field elongation, vent distribution and tectonic evolution of continental rift: The Main Ethiopian Rift example

    Science.gov (United States)

    Mazzarini, Francesco; Le Corvec, Nicolas; Isola, Ilaria; Favalli, Massimiliano

    2015-04-01

    Magmatism and faulting operate in continental rifts and interact at a variety of scales, however their relationship is complex. The African rift, being the best example for both active continental rifting and magmatism, provides the ideal location to study the interplay between the two mechanisms. The Main Ethiopian Rift (MER), which connects the Afar depression in the north with the Turkana depression and Kenya Rift to the south, consists of two distinct systems of normal faults and its floor is scattered with volcanic fields formed by tens to several hundreds monogenetic, generally basaltic, small volcanoes and composite volcanoes and small calderas. The distribution of vents defines the overall shape of the volcanic field. Previous work has shown that the distribution of volcanic vents and the shape of a field are linked to its tectonic environment and its magmatic system. In order to distinguish the impact of each mechanism, we analyzed four volcanic fields located at the boundary between the central and northern MER, three of them (Debre Zeyit, Wonji and Kone) grew in the rift valley and one (Akaki) on the western rift shoulder. The elongation and shape of the fields were analyzed based on their vent distribution using the Principal Component Analysis (PCA), the Vent-to-Vent Distance (VVD), and the two dimensional symmetric Gaussian kernel density estimate methods. We extracted from these methods several parameters characterizing the spatial distribution of points (e.g., eccentricity (e), eigenvector index (evi), angular dispersion (Da)). These parameters allow to define at least three types of shape for volcanic fields: strong elongate (line and ellipse), bimodal/medium elongate (ellipse) and dispersed (circle) shapes. Applied to the natural example, these methods well differentiate each volcanic field. For example, the elongation of the field increases from shoulder to rift axis inversely to the angular dispersion. In addition, the results show that none of

  2. Applying geophysical surveys for studying subsurface geology of monogenetic volcanic fields: the example of La Garrotxa Volcanic Field (NE of Iberian Peninsula)

    Science.gov (United States)

    Bolós, Xavier; Barde-Cabusson, Stéphanie; Pedrazzi, Dario; Martí, Joan; Casas, Albert; Lovera, Raúl; Nadal-Sala, Daniel

    2014-05-01

    Improving knowledge of the shallowest part of the feeding system of monogenetic volcanoes and the relationship with the subsurface geology is an important task. We applied high-precision geophysical techniques that are self-potential and electrical resistivity tomography, for the exploration of the uppermost part of the substrate of La Garrotxa Volcanic Field, which is part of the European Cenozoic Rift System. Previous geophysical studies carried out in the same area at a less detailed scale were aimed at identifying deeper structures, and together constitute the basis to establish volcanic susceptibility in La Garrotxa. Self-potential study allowed identifying key areas where electrical resistivity tomography could be conducted. Dykes and faults associated with several monogenetic cones were identified through the generation of resistivity models. The combined results confirm that shallow tectonics controlling the distribution of the foci of eruptive activity in this volcanic zone mainly correspond to NNW-SSE and accessorily by NNE-SSW Neogene extensional fissures and faults and concretely show the associated magmatic intrusions. These studies show that previous alpine tectonic structures played no apparent role in controlling the loci of this volcanism. Furthermore, the results obtained show that the changes in eruption dynamics occurring at different vents located at relatively short distances in this volcanic area can be controlled by shallow stratigraphical, structural, and hydrogeological features underneath these monogenetic volcanoes. This study was partially funded by the Beca Ciutat d'Olot en Ciències Naturals and the European Commission (FT7 Theme: ENV.2011.1.3.3-1; Grant 282759: "VUELCO").

  3. The Quaternary and Pliocene Yellowstone Plateau volcanic field of Wyoming, Idaho, and Montana

    Science.gov (United States)

    Christiansen, Robert L.

    2001-01-01

    This region of Yellowstone National Park has been the active focus of one of the Earth's largest magmatic systems for more than 2 million years. The resulting volcanism has been characterized by the eruption of voluminous rhyolites and subordinate basalts but virtually no lavas of intermediate composition. The magmatic system at depth remains active and drives the massive hydrothermal circulation for which the park is widely known. Studies of the volcanic field using geologic mapping and petrology have defined three major cycles of rhyolitic volcanism, each climaxed by the eruption of a rhyolitic ash-flow sheet having a volume of hundreds of thousands of cubic kilometers. The field also has been analyzed in terms of its magmatic and tectonic evolution, including its regional relation to the Snake River plain and to basin-range tectonic extension.

  4. Petrologic and petrographic variation of youthful eruptive products in the Tuxtla Volcanic Field, Veracruz, Mexico

    Science.gov (United States)

    Parrish, C. B.; Kobs Nawotniak, S. E.; Fredrick, K. C.; Espindola, J.

    2010-12-01

    The Tuxtla Volcanic Field (TVF) is located near the Gulf of Mexico in the southern part of the state of Veracruz, Mexico. Volcanism in the region began around 7 Ma and has continued until recent times with the volcano San Martín Tuxtla’s latest eruptions in AD 1664 and 1793. The TVF rocks are mainly of alkaline composition and have been divided into two separate volcanic series, an older and younger. The TVF is a structural high located between the Veracruz Basin to the southwest and the Gulf of Mexico to the northeast, characterized by relatively thin crust with the depth to the Moho around 28 to 34 km. The TVF is unique because it is isolated from the nearest volcanic fields (the Mexican Volcanic Belt, Central American Volcanic Belt and the Eastern Alkaline Province) by at least 230km and because of the on-going debate over its magmatic origin. Many models have been proposed to explain the TVF’s alkaline nature in a unique location with most linking it either to the subduction of the Cocos plate to the west of Mexico and/or to extensional faulting in the region. The purpose of our study was to determine systematic changes in the youthful volcanic deposits across the TVF. Regional and local mapping was conducted and lava and scoria samples were collected from seven sites associated with two vent clusters in the TVF. Mapping of the easternmost cluster of deposits suggests chronological emplacement of the deposits through superposition and vent location and morphology. The petrography of lava and tephra deposits may further indicate magmatic origins and other factors influencing the development of the field, including chronology and possible mixing and/or differentiation. Previous published studies analyzed samples near the San Martin Tuxtla volcanic center. Their data is used as a comparative reference for these samples, most of which were collected from another, younger cluster east of Laguna Catemaco. From this study, a better understanding of past eruptive

  5. Volcanic ash layers in blue ice fields (Beardmore Glacier Area, Antarctica): Iridium enrichments

    Science.gov (United States)

    Koeberl, Christian

    Dust bands on blue ice fields in Antarctica have been studied and have been identified to originate from two main sources: bedrock debris scraped up from the ground by the glacial movement (these bands are found predominantly at fractures and shear zones in the ice near moraines), and volcanic debris deposited on and incorporated in the ice by large-scale eruptions of Antarctic (or sub-Antractic) volcanoes. Ice core studies have revealed that most of the dust layers in the ice cores are volcanic (tephra) deposits which may be related to some specific volcanic eruptions. These eruptions have to be related to some specific volcanic eruptions. These eruptions have to be relatively recent (a few thousand years old) since ice cores usually incorporate younger ice. In contrast, dust bands on bare blue ice fields are much older, up to a few hundred thousand years, which may be inferred from the rather high terrestrial age of meteorites found on the ice and from dating the ice using the uranium series method. Also for the volcanic ash layers found on blue ice fields correlations between some specific volcanoes (late Cenozoic) and the volcanic debris have been inferred, mainly using chemical arguments. During a recent field expedition samples of several dust bands found on blue ice fields at the Lewis Cliff Ice Tongue were taken. These dust band samples were divided for age determination using the uranium series method, and chemical investigations to determine the source and origin of the dust bands. The investigations have shown that most of the dust bands found at the Ice Tongue are of volcanic origin and, for chemical and petrological reasons, may be correlated with Cenozoic volcanoes in the Melbourne volcanic province, Northern Victoria Land, which is at least 1500 km away. Major and trace element data have been obtained and have been used for identification and correlation purposes. Recently, some additional trace elements were determined in some of the dust band

  6. Field-trip guide to mafic volcanism of the Cascade Range in Central Oregon—A volcanic, tectonic, hydrologic, and geomorphic journey

    Science.gov (United States)

    Deligne, Natalia I.; Mckay, Daniele; Conrey, Richard M.; Grant, Gordon E.; Johnson, Emily R.; O'Connor, Jim; Sweeney, Kristin

    2017-08-16

    The Cascade Range in central Oregon has been shaped by tectonics, volcanism, and hydrology, as well as geomorphic forces that include glaciations. As a result of the rich interplay between these forces, mafic volcanism here can have surprising manifestations, which include relatively large tephra footprints and extensive lava flows, as well as water shortages, transportation and agricultural disruption, and forest fires. Although the focus of this multidisciplinary field trip will be on mafic volcanism, we will also look at the hydrology, geomorphology, and ecology of the area, and we will examine how these elements both influence and are influenced by mafic volcanism. We will see mafic volcanic rocks at the Sand Mountain volcanic field and in the Santiam Pass area, at McKenzie Pass, and in the southern Bend region. In addition, this field trip will occur during a total solar eclipse, the first one visible in the United States in more than 25 years (and the first seen in the conterminous United States in more than 37 years).The Cascade Range is the result of subduction of the Juan de Fuca plate underneath the North American plate. This north-south-trending volcanic mountain range is immediately downwind of the Pacific Ocean, a huge source of moisture. As moisture is blown eastward from the Pacific on prevailing winds, it encounters the Cascade Range in Oregon, and the resulting orographic lift and corresponding rain shadow is one of the strongest precipitation gradients in the conterminous United States. We will see how the products of the volcanoes in the central Oregon Cascades have had a profound influence on groundwater flow and, thus, on the distribution of Pacific moisture. We will also see the influence that mafic volcanism has had on landscape evolution, vegetation development, and general hydrology.

  7. Mapping Planetary Volcanic Deposits: Identifying Vents and Distinguishing between Effects of Eruption Conditions and Local Storage and Release on Flow Field Morphology

    Science.gov (United States)

    Bleacher, J. E.; Eppler, D. B.; Skinner, J. A.; Evans, C. A.; Feng, W.; Gruener, J. E.; Hurwitz, D. M.; Whitson, P.; Janoiko, B.

    2014-01-01

    Terrestrial geologic mapping techniques are regularly used for "photogeologic" mapping of other planets, but these approaches are complicated by the diverse type, areal coverage, and spatial resolution of available data sets. When available, spatially-limited in-situ human and/or robotic surface observations can sometimes introduce a level of detail that is difficult to integrate with regional or global interpretations. To assess best practices for utilizing observations acquired from orbit and on the surface, our team conducted a comparative study of geologic mapping and interpretation techniques. We compared maps generated for the same area in the San Francisco Volcanic Field (SFVF) in northern Arizona using 1) data collected for reconnaissance before and during the 2010 Desert Research And Technology Studies campaign, and 2) during a traditional, terrestrial field geology study. The operations, related results, and direct mapping comparisons are discussed in companion LPSC abstracts. Here we present new geologic interpretations for a volcanic cone and related lava flows as derived from all approaches involved in this study. Mapping results indicate a need for caution when interpreting past eruption conditions on other planetary surfaces from orbital data alone.

  8. Mapping Planetary Volcanic Deposits: Identifying Vents and Distingushing between Effects of Eruption Conditions and Local Lava Storage and Release on Flow Field Morphology

    Science.gov (United States)

    Bleacher, J. E.; Eppler, D. B.; Skinner, J. A.; Evans, C. A.; Feng, W.; Gruener, J. E.; Hurwitz, D. M.; Whitson, P.; Janoiko, B.

    2014-01-01

    Terrestrial geologic mapping techniques are regularly used for "photogeologic" mapping of other planets, but these approaches are complicated by the diverse type, areal coverage, and spatial resolution of available data sets. When available, spatially-limited in-situ human and/or robotic surface observations can sometimes introduce a level of detail that is difficult to integrate with regional or global interpretations. To assess best practices for utilizing observations acquired from orbit and on the surface, our team conducted a comparative study of geologic mapping and interpretation techniques. We compared maps generated for the same area in the San Francisco Volcanic Field (SFVF) in northern Arizona using 1) data collected for reconnaissance before and during the 2010 Desert Research And Technology Studies campaign, and 2) during a traditional, terrestrial field geology study. The operations, related results, and direct mapping comparisons are discussed in companion LPSC abstracts [1-3]. Here we present new geologic interpretations for a volcanic cone and related lava flows as derived from all approaches involved in this study. Mapping results indicate a need for caution when interpreting past eruption conditions on other planetary surfaces from orbital data alone.

  9. Anomalous Geologic Setting of the Spencer-High Point Volcanic Field, Eastern Snake River Plain, Idaho

    Science.gov (United States)

    Iwahashi, G. S.; Hughes, S. S.

    2006-12-01

    The Spencer-High Point (SHP) volcanic field comprises an ~1700 sq km mafic volcanic rift zone located near Yellowstone in the eastern Snake River Plain (ESRP). SHP lava flows are both similar to and distinct from typical olivine tholeiite lavas of the ESRP. SHP has unique physical volcanic features characterized by numerous cinder cones and short lava flows; whereas, spatter ramparts, fissures and longer flows dominate in other ESRP regions. Topography and aerial photos indicate that vents are generally aligned northwest- southeast, which is sub-parallel to adjacent Basin and Range faults in much of the ESRP. Yet individual vents and other structural elements in SHP where Basin and Range, ESRP and thrust-faulted mountain belts all intersect, are elongated in a more east-west direction. Distinct structural control is manifested in an overall southward slope over the entire volcanic field. Short lava flows tend to flow north or south off of a central topographically higher zone of overlapping lava flows and smaller vents. Several smaller vents appear to be parasitic cones adjacent to larger eruptive centers. Contrary to these relations, preliminary geochemical data by Leeman (1982) and Kuntz et al. (1992) suggest SHP lavas are typical ESRP olivine tholeiite basalts, which notably have coarsely diktytaxitic texture. The central and eastern sections of the SHP field contain lavas with large (3-8cm), clear, euhedral plagioclase phenocrysts but without diktytaxitic texture. Lava flows in the central and eastern sections of SHP volcanic field are pahoehoe. These also contain crustal xenoliths implying a prolonged crustal history. Geochemical whole rock and microprobe analyses are currently being processed for petrogenetic history.

  10. Impact of shade on outdoor thermal comfort—a seasonal field study in Tempe, Arizona

    Science.gov (United States)

    Middel, Ariane; Selover, Nancy; Hagen, Björn; Chhetri, Nalini

    2016-12-01

    Shade plays an important role in designing pedestrian-friendly outdoor spaces in hot desert cities. This study investigates the impact of photovoltaic canopy shade and tree shade on thermal comfort through meteorological observations and field surveys at a pedestrian mall on Arizona State University's Tempe campus. During the course of 1 year, on selected clear calm days representative of each season, we conducted hourly meteorological transects from 7:00 a.m. to 6:00 p.m. and surveyed 1284 people about their thermal perception, comfort, and preferences. Shade lowered thermal sensation votes by approximately 1 point on a semantic differential 9-point scale, increasing thermal comfort in all seasons except winter. Shade type (tree or solar canopy) did not significantly impact perceived comfort, suggesting that artificial and natural shades are equally efficient in hot dry climates. Globe temperature explained 51 % of the variance in thermal sensation votes and was the only statistically significant meteorological predictor. Important non-meteorological factors included adaptation, thermal comfort vote, thermal preference, gender, season, and time of day. A regression of subjective thermal sensation on physiological equivalent temperature yielded a neutral temperature of 28.6 °C. The acceptable comfort range was 19.1 °C-38.1 °C with a preferred temperature of 20.8 °C. Respondents exposed to above neutral temperature felt more comfortable if they had been in air-conditioning 5 min prior to the survey, indicating a lagged response to outdoor conditions. Our study highlights the importance of active solar access management in hot urban areas to reduce thermal stress.

  11. Impact of shade on outdoor thermal comfort-a seasonal field study in Tempe, Arizona.

    Science.gov (United States)

    Middel, Ariane; Selover, Nancy; Hagen, Björn; Chhetri, Nalini

    2016-12-01

    Shade plays an important role in designing pedestrian-friendly outdoor spaces in hot desert cities. This study investigates the impact of photovoltaic canopy shade and tree shade on thermal comfort through meteorological observations and field surveys at a pedestrian mall on Arizona State University's Tempe campus. During the course of 1 year, on selected clear calm days representative of each season, we conducted hourly meteorological transects from 7:00 a.m. to 6:00 p.m. and surveyed 1284 people about their thermal perception, comfort, and preferences. Shade lowered thermal sensation votes by approximately 1 point on a semantic differential 9-point scale, increasing thermal comfort in all seasons except winter. Shade type (tree or solar canopy) did not significantly impact perceived comfort, suggesting that artificial and natural shades are equally efficient in hot dry climates. Globe temperature explained 51 % of the variance in thermal sensation votes and was the only statistically significant meteorological predictor. Important non-meteorological factors included adaptation, thermal comfort vote, thermal preference, gender, season, and time of day. A regression of subjective thermal sensation on physiological equivalent temperature yielded a neutral temperature of 28.6 °C. The acceptable comfort range was 19.1 °C-38.1 °C with a preferred temperature of 20.8 °C. Respondents exposed to above neutral temperature felt more comfortable if they had been in air-conditioning 5 min prior to the survey, indicating a lagged response to outdoor conditions. Our study highlights the importance of active solar access management in hot urban areas to reduce thermal stress.

  12. Ground Penetrating Radar Field Studies of Planetary Analog Geologic Settings: Impact Ejecta, Volcanics, and Fluvial Terrains

    Science.gov (United States)

    Russell, P. S.; Grant, J. A.; Carter, L. M.; Garry, W.; Williams, K. K.; Morgan, G. A.; Daubar, I.; Bussey, B.

    2012-12-01

    Ground-Penetrating Radar (GPR) data from terrestrial analog environments can help constrain models for evolution of the lunar and martian surfaces, aid in interpretation of orbital SAR data, and help predict what might be encountered in the subsurface during future landed scientific or engineering operations. Results and interpretations presented here from impact ejecta (Barringer Meteorite Crater), volcanic deposits (Northern Arizona cinders overlying lavas, columnar-jointed Columbia River flood basalts, Hawaii lava flows), and terrains influenced by fluvial-related activity (channeled scablands megaflood bar, Mauna Kea glacio-fluvial deposits) focus on defining the radar "fingerprint" of geologic materials and settings that may be analogous to those found on the Moon and Mars. The challenge in using GPR in geologic investigations is the degree to which different geologic features and processes can be uniquely identified and distinguished in the data. Our approach to constraining this is to qualitatively and quantitatively characterize GPR signatures of different geological environments and to compare them with "ground-truth" observations of subsurface exposures immediately adjacent or subjacent to our GPR transects. Several sites were chosen in each field area based on accessibility, visual access to the subsurface, and presence of particular geologic features of interest. The interpreted distribution of blocks in impact ejecta at Meteor Crater, using a 400 MHz antenna (wavelength of 75 cm) is 1.5-3 blocks per m^3 in the upper 1 m (and 0.5-1 blocks per m^3 in the upper two meters), which is close to the in situ measured block distribution of 2-3 blocks larger than 0.25-0.30 m per m^3. This is roughly the detection limit to be expected from the λ/3 resolution approximation of radar wavelength and indicates that the 400 MHz GPR is characterizing the block population in ejecta. While megaflood bar deposits are also reflector-rich, individual reflectors are in

  13. A first hazard analysis of the Harrat Ash Shamah volcanic field, Syria-Jordan Borderline

    Science.gov (United States)

    Cagnan, Zehra; Akkar, Sinan; Moghimi, Saed

    2017-04-01

    The northernmost part of the Saudi Cenozoic Volcanic Fields, the 100,000 km2 Harrat Ash Shamah has hosted some of the most recent volcanic eruptions along the Syria-Jordan borderline. With rapid growth of the cities in this region, exposure to any potential renewed volcanism increased considerably. We present here a first-order probabilistic hazard analysis related to new vent formation and subsequent lava flow from Harrat Ash Shamah. The 733 visible eruption vent sites were utilized to develop a probability density function for new eruption sites using Gaussian kernel smoothing. This revealed a NNW striking zone of high spatial hazard surrounding the cities Amman and Irbid in Jordan. The temporal eruption recurrence rate is estimated to be approximately one vent per 3500 years, but the temporal record of the field is so poorly constrained that the lower and upper bounds for the recurrence interval are 17,700 yrs and 70 yrs, respectively. A Poisson temporal model is employed within the scope of this study. In order to treat the uncertainties associated with the spatio-temporal models as well as size of the area affected by the lava flow, the logic tree approach is adopted. For the Syria-Jordan borderline, the spatial variation of volcanic hazard is computed as well as uncertainty associated with these estimates.

  14. Internal architecture of the Tuxtla volcanic field, Veracruz, Mexico, inferred from gravity and magnetic data

    Science.gov (United States)

    Espindola, Juan Manuel; Lopez-Loera, Hector; Mena, Manuel; Zamora-Camacho, Araceli

    2016-09-01

    The Tuxtla Volcanic Field (TVF) is a basaltic volcanic field emerging from the plains of the western margin of the Gulf of Mexico in the Mexican State of Veracruz. Separated by hundreds of kilometers from the Trans-Mexican Volcanic Belt to the NW and the Chiapanecan Volcanic Arc to the SE, it stands detached not only in location but also in the composition of its rocks, which are predominantly alkaline. These characteristics make its origin somewhat puzzling. Furthermore, one of the large volcanoes of the field, San Martin Tuxtla, underwent an eruptive period in historical times (CE 1793). Such volcanic activity conveys particular importance to the study of the TVF from the perspective of volcanology and hazard assessment. Despite the above circumstances, few investigations about its internal structure have been reported. In this work, we present analyses of gravity and aeromagnetic data obtained from different sources. We present the complete Bouguer anomaly of the area and its separation into regional and residual components. The aeromagnetic data were processed to yield the reduction to the pole, the analytic signal, and the upward continuation to complete the interpretation of the gravity analyses. Three-dimensional density models of the regional and residual anomalies were obtained by inversion of the gravity signal adding the response of rectangular prisms at the nodes of a regular grid. We obtained a body with a somewhat flattened top at 16 km below sea level from the inversion of the regional. Three separate slender bodies with tops 6 km deep were obtained from the inversion of the residual. The gravity and magnetic anomalies, as well as the inferred source bodies that produce those geophysical anomalies, lie between the Sontecomapan and Catemaco faults, which are proposed as flower structures associated with an inferred deep-seated fault termed the Veracruz Fault. These fault systems along with magma intrusion at the lower crust are necessary features to

  15. Imaging subsurface density structure in Luynnier volcanic field, Saudi Arabia, using 3D gravity inversion technique

    Science.gov (United States)

    Aboud, Essam; El-shrief, Adel; Alqahtani, Faisal; Mogren, Saad

    2017-04-01

    On 19 May, 2009, an earthquake of magnitude (M=5.4) shocked the most volcanically active recent basaltic fields, Luynnier volcanic field, northwestern Saudi Arabia. This event was the largest recorded one since long time ago. Government evacuated the surrounding residents around the epicenter for over 3 months away from any future volcanic activity. The seismic event caused damages to buildings in the village around the epicenter and resulted in surface fissure trending in NNW-SSE direction with about 8 km length. Seismologists from Saudi Geological Survey (SGS) worked out on locating the epicenter and the cause of this earthquake. They collected seismic data from Saudi Geological Surveys Station Network as well as installed broadband seismic stations around the region of the earthquake. They finally concluded that the main cause of the M=5.4 event is dike intrusion at depth of about 5 km (not reached to the surface). In the present work, we carried out detailed ground/airborne gravity survey around the surficial fissure to image the subsurface volcanic structure where about 380 gravity stations were recorded covering the main fissure in an area of 600 km2. Gravity data was analyzed using CET edge detection tools and 3D inversion technique. The results revealed that, there is a magma chamber/body beneath the surface at 5-20 km depth and the main reason for the M=5.4 earthquake is tectonic settings of the Red Sea. Additionally, the area is characterized by set of faults trending in NW direction, parallel to the Red Sea, and most of the volcanic cones were located on faults/contacts implying that, they are structurally controlled. The 8-km surficial crack is extended SE underneath the surface.

  16. Origin of metaluminous and alkaline volcanic rocks of the Latir volcanic field, northern Rio Grande rift, New Mexico

    Science.gov (United States)

    Johnson, C.M.; Lipman, P.W.

    1988-01-01

    Volcanic rocks of the Latir volcanic field evolved in an open system by crystal fractionation, magma mixing, and crustal assimilation. Early high-SiO2 rhyolites (28.5 Ma) fractionated from intermediate compositionmagmas that did not reach the surface. Most precaldera lavas have intermediate-compositions, from olivine basaltic-andesite (53% SiO2) to quartz latite (67% SiO2). The precaldera intermediate-composition lavas have anomalously high Ni and MgO contents and reversely zoned hornblende and augite phenocrysts, indicating mixing between primitive basalts and fractionated magmas. Isotopic data indicate that all of the intermediate-composition rocks studied contain large crustal components, although xenocrysts are found only in one unit. Inception of alkaline magmatism (alkalic dacite to high-SiO2 peralkaline rhyolite) correlates with, initiation of regional extension approximately 26 Ma ago. The Questa caldera formed 26.5 Ma ago upon eruption of the >500 km3 high-SiO2 peralkaline Amalia Tuff. Phenocryst compositions preserved in the cogenetic peralkaline granite suggest that the Amalia Tuff magma initially formed from a trace element-enriched, high-alkali metaluminous magma; isotopic data suggest that the parental magmas contain a large crustal component. Degassing of water- and halogen-rich alkali basalts may have provided sufficient volatile transport of alkalis and other elements into the overlying silicic magma chamber to drive the Amalia Tuff magma to peralkaline compositions. Trace element variations within the Amalia Tuff itself may be explained solely by 75% crystal fractionation of the observed phenocrysts. Crystal settling, however, is inconsistent with mineralogical variations in the tuff, and crystallization is thought to have occurred at a level below that tapped by the eruption. Spatially associated Miocene (15-11 Ma) lavas did not assimilate large amounts of crust or mix with primitive basaltic magmas. Both mixing and crustal assimilation processes

  17. Rocky 7 prototype Mars rover field geology experiments 1. Lavic Lake and sunshine volcanic field, California

    Science.gov (United States)

    Arvidson, R. E.; Acton, C.; Blaney, D.; Bowman, J.; Kim, S.; Klingelhofer, G.; Marshall, J.; Niebur, C.; Plescia, J.; Saunders, R.S.; Ulmer, C.T.

    1998-01-01

    Experiments with the Rocky 7 rover were performed in the Mojave Desert to better understand how to conduct rover-based, long-distance (kilometers) geological traverses on Mars. The rover was equipped with stereo imaging systems for remote sensing science and hazard avoidance and 57Fe Mo??ssbauer and nuclear magnetic resonance spectrometers for in situ determination of mineralogy of unprepared rock and soil surfaces. Laboratory data were also obtained using the spectrometers and an X ray diffraction (XRD)/XRF instrument for unprepared samples collected from the rover sites. Simulated orbital and descent image data assembled for the test sites were found to be critical for assessing the geologic setting, formulating hypotheses to be tested with rover observations, planning traverses, locating the rover, and providing a regional context for interpretation of rover-based observations. Analyses of remote sensing and in situ observations acquired by the rover confirmed inferences made from orbital and simulated descent images that the Sunshine Volcanic Field is composed of basalt flows. Rover data confirmed the idea that Lavic Lake is a recharge playa and that an alluvial fan composed of sediments with felsic compositions has prograded onto the playa. Rover-based discoveries include the inference that the basalt flows are mantled with aeolian sediment and covered with a dense pavement of varnished basalt cobbles. Results demonstrate that the combination of rover remote sensing and in situ analytical observations will significantly increase our understanding of Mars and provide key connecting links between orbital and descent data and analyses of returned samples. Copyright 1998 by the American Geophysical Union.

  18. Magma evolution and ascent at the Craters of the Moon and neighboring volcanic fields, southern Idaho, USA: implications for the evolution of polygenetic and monogenetic volcanic fields

    Science.gov (United States)

    Putirka, Keith D.; Kuntz, Mel A.; Unruh, Daniel M.; Vaid, Nitin

    2009-01-01

    The evolution of polygenetic and monogenetic volcanic fields must reflect differences in magma processing during ascent. To assess their evolution we use thermobarometry and geochemistry to evaluate ascent paths for neighboring, nearly coeval volcanic fields in the Snake River Plain, in south-central Idaho, derived from (1) dominantly Holocene polygenetic evolved lavas from the Craters of the Moon lava field (COME) and (2) Quaternary non-evolved, olivine tholeiites (NEOT) from nearby monogenetic volcanic fields. These data show that NEOT have high magmatic temperatures (1205 + or - 27 degrees C) and a narrow temperature range (50 degrees C). Prolonged storage of COME magmas allows them to evolve to higher 87Sr/86Sr and SiO2, and lower MgO and 143Nd/144Nd. Most importantly, ascent paths control evolution: NEOT often erupt near the axis of the plain where high-flux (Yellowstone-related), pre-Holocene magmatic activity replaces granitic middle crust with basaltic sills, resulting in a net increase in NEOT magma buoyancy. COME flows erupt off-axis, where felsic crustal lithologies sometimes remain intact, providing a barrier to ascent and a source for crustal contamination. A three-stage ascent process explains the entire range of erupted compositions. Stage 1 (40-20 km): picrites are transported to the middle crust, undergoing partial crystallization of olivine + or - clinopyroxene. COME magmas pass through unarmored conduits and assimilate 1% or less of ancient gabbroic crust having high Sr and 87Sr/86Sr and low SiO2. Stage 2 (20-10 km): magmas are stored within the middle crust, and evolve to moderate MgO (10%). NEOT magmas, reaching 10% MgO, are positively buoyant and migrate through the middle crust. COME magmas remain negatively buoyant and so crystallize further and assimilate middle crust. Stage 3 (15-0 km): final ascent and eruption occurs when volatile contents, increased by differentiation, are sufficient (1-2 wt % H2O) to provide magma buoyancy through the

  19. Records of magmatic change as preserved in zircon: examples from the Yellowstone Volcanic Field

    Science.gov (United States)

    Rivera, T. A.

    2015-12-01

    Zircon crystals have been used as proxies for their host magmatic composition and as records of the evolution and differentiation of silicic magma systems through the use of integrated techniques such as cathodoluminescence imaging, LA-ICPMS trace element analysis, thermometry, and high-precision CA-IDTIMS U/Pb dating. This petrochronologic approach can aid in identifying crystal populations arising from discrete pulses of magmatism, reconstructing the growth histories of those populations, quantifying the chemical evolution of the host magma, and determining the timing and tempo of that chemical evolution. The Yellowstone Volcanic Field hosts both large and small volume silicic eruptions whose zircon records can provide insights to magmatic processes using a petrochronologic approach. Morphological and thermochemical trends preserved in zircon grains extracted from the three Yellowstone super-eruptions and a small volume precursory eruption indicate that magmatism in the volcanic field is punctuated, characterized by numerous pulses of melting, differentiation, and solidification occurring prior to eruption. U/Pb zircon dating constrains magma assembly to geologically short timescales, with populations of earlier solidified zircon incorporated into the nascent magma just prior to eruption. This requires punctuated intervals of high magmatic flux be superimposed on longer durations of a much lower background flux. Thus super-eruptions within the Yellowstone Volcanic Field result from rapid production and evolution of magma, and preceded by periods of smaller volume magma production that undergo similar differentiation processes over comparable timescales.

  20. Geology, geochronology, and paleogeography of the southern Sonoma volcanic field and adjacent areas, northern San Francisco Bay region, California

    Science.gov (United States)

    Wagner, David L.; Saucedo, George J.; Clahan, Kevin B.; Fleck, Robert J.; Langenheim, Victoria E.; McLaughlin, Robert J.; Sarna-Wojcicki, Andrei M.; Allen, James R.; Deino, Alan L.

    2011-01-01

    Recent geologic mapping in the northern San Francisco Bay region (California, USA) supported by radiometric dating and tephrochronologic correlations, provides insights into the framework geology, stratigraphy, tectonic evolution, and geologic history of this part of the San Andreas transform plate boundary. There are 25 new and existing radiometric dates that define three temporally distinct volcanic packages along the north margin of San Pablo Bay, i.e., the Burdell Mountain Volcanics (11.1 Ma), the Tolay Volcanics (ca. 10–8 Ma), and the Sonoma Volcanics (ca. 8–2.5 Ma). The Burdell Mountain and the Tolay Volcanics are allochthonous, having been displaced from the Quien Sabe Volcanics and the Berkeley Hills Volcanics, respectively. Two samples from a core of the Tolay Volcanics taken from the Murphy #1 well in the Petaluma oilfield yielded ages of 8.99 ± 0.06 and 9.13 ± 0.06 Ma, demonstrating that volcanic rocks exposed along Tolay Creek near Sears Point previously thought to be a separate unit, the Donnell Ranch volcanics, are part of the Tolay Volcanics. Other new dates reported herein show that volcanic rocks in the Meacham Hill area and extending southwest to the Burdell Mountain fault are also part of the Tolay Volcanics. In the Sonoma volcanic field, strongly bimodal volcanic sequences are intercalated with sediments. In the Mayacmas Mountains a belt of eruptive centers youngs to the north. The youngest of these volcanic centers at Sugarloaf Ridge, which lithologically, chemically, and temporally matches the Napa Valley eruptive center, was apparently displaced 30 km to the northwest by movement along the Carneros and West Napa faults. The older parts of the Sonoma Volcanics have been displaced at least 28 km along the Rodgers Creek fault since ca. 7 Ma. The Petaluma Formation also youngs to the north along the Rodgers Creek–Hayward fault and the Bennett Valley fault. The Petaluma basin formed as part of the Contra Costa basin in the Late Miocene and

  1. Geologic and geophysical investigations of the Zuni-Bandera volcanic field, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ander, M.E.; Heiken, G.; Eichelberger, J.; Laughlin, A.W.; Huestis, S.

    1981-05-01

    A positive, northeast-trending gravity anomaly, 90 km long and 30 km wide, extends southwest from the Zuni uplift, New Mexico. The Zuni-Bandera volcanic field, an alignment of 74 basaltic vents, is parallel to the eastern edge of the anomaly. Lavas display a bimodal distribution of tholeiitic and alkalic compositions, and were erupted over a period from 4 Myr to present. A residual gravity profile taken perpendicular to the major axis of the anomaly was analyzed using linear programming and ideal body theory to obtain bounds on the density contrast, depth, and minimum thickness of the gravity body. Two-dimensionality was assumed. The limiting case where the anomalous body reaches the surface gives 0.1 g/cm/sup 3/ as the greatest lower bound on the maximum density contrast. If 0.4 g/cm/sup 3/ is taken as the geologically reasonable upper limit on the maximum density contrast, the least upper bound on the depth of burial is 3.5 km and minimum thickness is 2 km. A shallow mafic intrusion, emplaced sometime before Laramide deformation, is proposed to account for the positive gravity anomaly. Analysis of a magnetotelluric survey suggests that the intrusion is not due to recent basaltic magma associated with the Zuni-Bandera volcanic field. This large basement structure has controlled the development of the volcanic field; vent orientations have changed somewhat through time, but the trend of the volcanic chain followed the edge of the basement structure. It has also exhibited some control on deformation of the sedimentary section.

  2. Effects of fire interval restoration on carbon and nitrogen in sedimentary- and volcanic-derived soils of the Mogollon Rim, Arizona

    Science.gov (United States)

    Dan Neary; Steven T. Overby; Sally M. Haase

    2003-01-01

    Prescribed fire was returned into over-stocked ponderosa pine stands on the Mogollon Rim of Arizona for the purpose of restoring fire into the ecosystem and removing fuel buildups. Prescribed fires have been ignited at intervals of 1, 2, 4, 6, 8, and 10 years to determine the best fire return interval for Southwest ponderosa pine ecosystems. Two sites were treated; one...

  3. Ecoregions of Arizona (poster)

    Science.gov (United States)

    Griffith, Glenn E.; Omernik, James M.; Johnson, Colleen Burch; Turner, Dale S.

    2014-01-01

    Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources; they are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions stratify the environment by its probable response to disturbance. These general purpose regions are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and nongovernment organizations that are responsible for different types of resources within the same geographical areas. The Arizona ecoregion map was compiled at a scale of 1:250,000. It revises and subdivides an earlier national ecoregion map that was originally compiled at a smaller scale. The approach used to compile this map is based on the premise that ecological regions can be identified through the analysis of the spatial patterns and the composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity. These phenomena include geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral hierarchical scheme has been adopted for different levels of ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 50 regions. At level III, the continental United States contains 105 ecoregions and the conterminous United States has 85 ecoregions. Level IV is a further subdivision of level III ecoregions. Arizona contains arid deserts and canyonlands, semiarid shrub- and grass-covered plains, woodland- and shrubland-covered hills, lava fields and volcanic plateaus, forested mountains, glaciated

  4. The `Strawberry Volcanic Field' of Northeastern Oregon: Another Piece of the CRB Puzzle?

    Science.gov (United States)

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

    2010-12-01

    The Mid to Late Miocene Strawberry Volcanics field (SVF) located along the southern margin of the John Day valley of NE Oregon, comprise a diverse group of volcanic rocks ranging from basalt to rhyolite. The main outcrop area of the SVF (3,400 km2) is bordered by units from the Columbia River Basalt Group (CRBG), with the main CRB units to the north, the Picture Gorge Basalt to the east and Steens Basalt to the south. The geographic position and age of the Strawberry Volcanics make a genetic relationship to CRB volcanism likely, yet little is known about this diverse volcanic field. This research aims at refining the stratigraphic and age relationships as well as the petrology and geochemistry of magmas associated with the SVF. Previous investigations (e.g. Robyn, 1977) found that the SVF was active between 20 to 10 Ma with the main pulse largely being coeval with the 15 Ma CRBG eruptions. Lavas and tuffs from the SVF are calc-alkaline with low FeO*/MgO (~ 2.56 wt. %), high Al2O3 (~ 16.4 wt. %), low TiO2 (~ 1.12 wt.%), and span the entire compositional range from basalt to rhyolite (47-78 wt. % SiO2) with andesite as the dominant lithology. Basaltic lavas from the SVF have compositional affinities to earlier Steens Basalt, and some trace element concentrations and ratios are indistinguishable from those of CRBG lavas (e.g. Zr, Ba, Sr, and Ce/Y). Andesites are calc-alkaline, but contrary to typical arc (orogenic) andesites, SVF andesites are exceedingly phenocryst poor (Strawberry Volcanics are largely the product of hot-spot related basaltic magmas interacting with the continental crust. The range in compositions from calc-alkaline andesite to rhyolite may be attributed to the hybridization of mantle-derived and crustal melts, with the more evolved compositions reflecting greater proportions of crustally derived material and/or higher degrees of differentiation. Furthermore, since the earliest SVF eruption is 3 Ma older than the proposed onset of the CRBG (~ 17 Ma

  5. Internal Structure of the Tuxtla Volcanic Field, Eastern mexico, Derived from Gravity and Aeromagnetic data.

    Science.gov (United States)

    Espindola, J. M.; Lopez Loera, H.; Zamora-Camacho, A.; Mena, M.

    2016-12-01

    The TVF is a basaltic volcanic field located in the western margin of the Gulf of Mexico in the Mexican State of Veracruz, about 230 km to the SSE of the easternmost tip of the Trans-Mexican Volcanic Belt, and about the same distance from El Chichon volcano, in the Chiapanecan Volcanic Arc, to the SE. It is separated from both volcanic chains also in composition as its rocks are predominantly alkaline. These characteristics prompt questions about its origin, more so since, one of the large volcanoes of the field, San Martin Tuxtla, erupted in 1793 CE. The TVF stands out from the lowlands of the Veracruz margins and is approximately surrounded by the 100 m contour line, while the surrounding areas along the Gulf of Mexico shoreline lie below this contour. Assuming that the rocks above this contour were deposited by the volcanic activity in the area, a good estimate of its volume is obtained by calculating the amount of material contained above this contour. We performed this calculation from the digital elevation model of the area received from restitutions carried out by Mexicós National Institute of Statistics, Geography, and Informatics (Spanish acronym: INEGI). We obtained a total amount of 1300 km3 for this volume. To understand more about the volcanism that has deposited this volume of products, we analyzed the gravimetric and aeromagnetic anomalies of the area and obtained a density model of the causative body. We got a body with a somewhat flattened top at 16 km below sea level from the inversion of the regional. Three separate slender bodies with tops 6 km deep were obtained from the inversion of the residual. The gravity and magnetic anomalies, as well as the inferred source bodies that produce those geophysical anomalies, lie between two large regional faults (Sontecomapan and Catemaco faults), which are proposed as flower structures associated with an inferred deep-seated fault termed the Veracruz Fault. We suggest that the process leading to the

  6. Geomorphometric analysis of the scoria cones of the San Francisco Volcanic Field using polar coordinate transformation

    Science.gov (United States)

    Vörös, Fanni; Koma, Zsófia; Karátson, Dávid; Székely, Balázs

    2016-04-01

    Scoria cones are often studied using geomorphometric and traditional GIS methods, e.g. aspect, slope histograms, area, cone height/width ratio. In order to enhance the non-symmetric shape components in contrast to the conical forms, we used a new approach in our research: the polar coordinate transformation (PCT) introduced by Székely & Karátson (2004). The study area is the classic cluster of scoria cones at the San Francisco Volcanic Field (SFVF) encompassing roughly 600 scoria cones as well as the San Francisco stratovolcano. Our goal is to analyse the even slight asymmetric shape of the scoria cones, and to generalize our findings. The area is a well-studied volcanic field, with a great number of available geological and geomorphological information, so comparing our PCT results with the data in literature is feasible. Polar coordinate transformation, being a one-to-one transformation, maps the original Cartesian coordinates (X, Y in meters) to radial distance (m) and azimuth (°) values. Our inputs were digitized polygons. We created images in the transformed coordinate system that clearly show the asymmetrical shape of the scoria cones. This asymmetry is found to be related to some extent to denudation, and to the age of the volcanic edifice that correlates with differential erosion. However, original asymmetries related to formation (e.g. rifting, emplacement on slope, eruption variations etc.) are also reasonable. The applied technique allows to define new derivatives of volcano-geomorphological parameters. The resultant scoria cone patterns have been manually categorized, however, the results are suitable for automated classification which is our next purpose. BSz contributed as an Alexander von Humboldt Research Fellow. Székely, B. & Karátson, D. (2004): DEM-based morphometry as a tool for reconstructing primary volcanic landforms: examples from the Börzsöny Mountains, Hungary, Geomorphology 63:25-37.

  7. Boundary of the southwestern Nevada volcanic field from Laczniak and others (1996), for the Death Valley regional ground-water flow system study, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the boundary of the southwestern Nevada volcanic field (SWNVF), an area of thick, regionally distributed volcanic rocks within the...

  8. Quaternary volcanism in the Colorado Plateau-Basin and Range transition zone: Zuni-Bandera and nearby volcanic fields

    Science.gov (United States)

    Cascadden, Tracey Elaine

    Early (ca. 700 ka) voluminous tholeiites in the Zuni-Bandera volcanic field (ZBVF) were followed by smaller volume alkalic, transitional and tholeiitic basalts, intermittently erupted from ca. 200 ka through 3 ka. In some cases, lavas of different chemical characteristics were erupted from the same vent, or from contemporaneous clusters of vents. El Calderon cinder cone erupted magmas derived from two different sources. Early alkalic eruptions, derived from a depleted (asthenospheric) source, were followed by more voluminous tholeiitic flows derived from an enriched (lithospheric) source. The tholeiite flow erupted at ca. 80 ka during a high-amplitude excursion (possibly an aborted reversal) of the geomagnetic field, as indicated by a paleomagnetic direction with declination = 271sp° , inclination = -17sp° (N = 10, alphasb{95}=4.4sp° ,\\ kappa = 124). This tholeiite has higher Ksb2O, TiOsb2, MgO, Co, Nb, Sr, Zr and LREE contents than other ZBVF tholeiites. The Candelaria Cluster comprises four volcanoes, within a four kmsp2 area, that erupted alkalic and transitional lavas from an asthenospheric source and tholeiitic lavas from a lithospheric source. Lavas from all four vents record moderate-amplitude paleomagnetic secular variation (declination = 32sp° , inclination = 56sp° , N = 17, alphasb{95}=2.8sp° ,\\ kappa = 189) indicating eruption within a very short time span, conceivably less than 100 years. The ZBVF is located within the Basin and Range/Rio Grande rift - Colorado Plateau transition zone, where extension has thinned the crust and lithosphere with respect to the Colorado Plateau but not as much as in the more highly-extended Basin and Range. Contemporaneous eruption of magmas from different mantle sources is consistent with a model in which transition zone alkalic magmas are generated at the boundary between upwelling depleted asthenosphere and residual enriched lithosphere, and tholeiitic magmas are derived from the lithosphere. The lack of

  9. Field-trip guide to a volcanic transect of the Pacific Northwest

    Science.gov (United States)

    Geist, Dennis; Wolff, John; Harpp, Karen

    2017-08-01

    The Pacific Northwest region of the United States provides world-class and historically important examples of a wide variety of volcanic features. This guide is designed to give a broad overview of the region’s diverse volcanism rather than focusing on the results of detailed studies; the reader should consult the reference list for more detailed information on each of the sites, and we have done our best to recognize previous field trip leaders who have written the pioneering guides. This trip derives from one offered as a component of the joint University of Idaho- Washington State University volcanology class taught from 1995 through 2014, and it borrows in theme from the classic field guide of Johnston and Donnelly-Nolan (1981). For readers interested in using this field guide as an educational tool, we have included an appendix with supplemental references to resources that provide useful background information on relevant topics, as well as a few suggestions for field-based exercises that could be useful when bringing students to these locations in the future. The 4-day trip begins with an examination of lava flow structures of the Columbia River Basalt, enormous lava fields that were emplaced during one of the largest eruptive episodes in Earth’s recent history. On the second day, the trip turns to the High Lava Plains, a bimodal volcanic province that transgressed from southeast to northwest from the Miocene through the Holocene, at the northern margin of the Basin and Range Province. This volcanic field provides excellent examples of welded ignimbrite, silicic lavas and domes, monogenetic basaltic lava fields, and hydrovolcanic features. The third day is devoted to a circumnavigation of Crater Lake, the result of one of the world’s best-documented caldera-forming eruptions. The caldera walls also expose the anatomy of Mount Mazama, a stratovolcano of the Cascade Range. The last day is spent at Newberry Volcano, a back-arc shield volcano topped by a

  10. Physical Volcanology and Hazard Analysis of a Young Volcanic Field: Black Rock Desert, Utah, USA

    Science.gov (United States)

    Hintz, A. R.

    2009-05-01

    The Black Rock Desert volcanic field, located in west-central Utah, consists of ~30 small-volume monogenetic volcanoes with compositions ranging from small rhyolite domes to large basaltic lava flow fields. The field has exhibited bimodal volcanism for > 9 Ma with the most recent eruption of Ice Springs volcano ˜ 600 yrs ago. Together this eruptive history along with ongoing geothermal activity attests to the usefulness of a hazard assessment. The likelihood of a future eruption in this area has been calculated to be ˜ 8% over the next 1 Ka (95% confidence). However, many aspects of this field such as the explosivity and nature of many of these eruptions are not well known. The physical volcanology of the Tabernacle Hill volcano, suggests a complicated episodic eruption that may have lasted up to 50 yrs. The initial phreatomagmatic eruptions at Tabernacle Hill are reported to have begun ~14 Ka. This initial eruptive phase produced a tuff cone approximately 150 m high and 1.5 km in diameter with distinct bedding layers. Recent mapping and sampling of Tabernacle Hill's lava field, tuff cone and intra-crater deposits were aimed at better constraining the eruptive history, physical volcanology, and explosive energy associated with this eruption. Blocks ejected during the eruption were mapped and analyzed to yield minimum muzzle velocities of 60 - 70 meters per second. These velocities were used in conjunction with an estimated shallow depth of explosion to calculate an energy yield of ˜ 0.5 kT.

  11. Volcanic Hazard Education through Virtual Field studies of Vesuvius and Laki Volcanoes

    Science.gov (United States)

    Carey, S.; Sigurdsson, H.

    2011-12-01

    Volcanic eruptions pose significant hazards to human populations and have the potential to cause significant economic impacts as shown by the recent ash-producing eruptions in Iceland. Demonstrating both the local and global impact of eruptions is important for developing an appreciation of the scale of hazards associated with volcanic activity. In order to address this need, Web-based virtual field exercises at Vesuvius volcano in Italy and Laki volcano in Iceland have been developed as curriculum enhancements for undergraduate geology classes. The exercises are built upon previous research by the authors dealing with the 79 AD explosive eruption of Vesuvius and the 1783 lava flow eruption of Laki. Quicktime virtual reality images (QTVR), video clips, user-controlled Flash animations and interactive measurement tools are used to allow students to explore archeological and geological sites, collect field data in an electronic field notebook, and construct hypotheses about the impacts of the eruptions on the local and global environment. The QTVR images provide 360o views of key sites where students can observe volcanic deposits and formations in the context of a defined field area. Video sequences from recent explosive and effusive eruptions of Carribean and Hawaiian volcanoes are used to illustrate specific styles of eruptive activity, such as ash fallout, pyroclastic flows and surges, lava flows and their effects on the surrounding environment. The exercises use an inquiry-based approach to build critical relationships between volcanic processes and the deposits that they produce in the geologic record. A primary objective of the exercises is to simulate the role of a field volcanologist who collects information from the field and reconstructs the sequence of eruptive processes based on specific features of the deposits. Testing of the Vesuvius and Laki exercises in undergraduate classes from a broad spectrum of educational institutions shows a preference for the

  12. Paleogene volcanism in Central Afghanistan: Possible far-field effect of the India-Eurasia collision

    Science.gov (United States)

    Motuza, Gediminas; Šliaupa, Saulius

    2017-10-01

    A volcanic-sedimentary succession of Paleogene age is exposed in isolated patches at the southern margin of the Tajik block in the Ghor province of Central Afghanistan. The volcanic rocks range from basalts and andesites to dacites, including adakites. They are intercalated with sedimentary rocks deposited in shallow marine environments, dated biostratigraphically as Paleocene-Eocene. This age corresponds to the age of the Asyābēd andesites located in the western Ghor province estimated by the 40Ar/39Ar method as 54 Ma. The magmatism post-dates the Cimmerian collision between the Tajik block (including the Band-e-Bayan block) and the Farah Rod block located to the south. While the investigated volcanic rocks apparently bear geochemical signatures typical to an active continental margin environment, it is presumed that the magmatism was related to rifting processes most likely initiated by far-field tectonics caused by the terminal collision of the Indian plate with Eurasia (Najman et al., 2017). This event led to the dextral movement of the Farah Rod block, particularly along Hari Rod (Herat) fault system, resulting in the development of a transtensional regime in the proximal southern margin of the Tajik block and giving rise to a rift basin where marine sediments were interbedded with pillow lavas intruded by sheeted dyke series.

  13. Channel and tube flow features associated with the Twin Craters Lava Flow, Zuni-Bandera Volcanic Field, NM: Insights into similar features on Mars

    Science.gov (United States)

    Samuels, R.; deWet, A.; Bleacher, J. E.; von Meerscheidt, H. C.; Hamilton, C.; Garry, W. B.

    2013-12-01

    The Zuni-Bandera Volcanic Field lies near the center of the Jemez lineament that extends from central Arizona to northeastern New Mexico. The Jemez lineament is a result of rifting in the Earth's crust and is associated with volcanic activity that spans the last 16 Ma. The youngest volcanic activity associated with the lineament includes basaltic lava that was erupted 3 ka ago to form the McCartys Flow. The Twin Craters flow is moderately older (18.0 ka), but it also well-preserved and provides an ideal location to investigate volcanic processes and landforms. In this study, we combined detailed field observations and mapping with remote sensing to better understand variations in morphology along the transport system of the flow . The Twin Craters flow is characterized as an aā and tube-fed pāhoehoe flow with braided or branching tubes and channels; and associated aā and pāhoehoe break-outs. It is possible that the variations in morphology along the same transport structure might be related to pre-flow slope, which might have also been variable along flow. Shatter ring features are thought to be related to changes in eruption rate, and therefore, local flux through the system. However, over-pressurization of the tube might also be related to changes in local discharge rate associated with the ponding and release of lava within the transport system that may be due to interactions between the lava and obstacles along the flow's path (see Mallonee et al., this meeting). Many of these features are similar to features present in the Tharsis Montes region of Mars and particularly on the southern apron of Ascraeus Mons. The detailed description of the morphology of the Twin Craters Lava Flow and the understanding of the emplacement mechanisms will be crucial in identifying the processes that formed the Ascraeus flows and channels. This will aid in determining if the lava surface textures are directly related to eruption conditions or if they have been significantly

  14. The Maars of the Tuxtla Volcanic Field: the Example of 'laguna Pizatal'

    Science.gov (United States)

    Espindola, J.; Zamora-Camacho, A.; Hernandez-Cardona, A.; Alvarez del Castillo, E.; Godinez, M.

    2013-12-01

    Los Tuxtlas Volcanic Field (TVF), also known as Los Tuxtlas massif, is a structure of volcanic rocks rising conspicuously in the south-central part of the coastal plains of eastern Mexico. The TVF seems related to the upper cretaceous magmatism of the NW part of the Gulf's margin (e.g. San Carlos and Sierra de Tamaulipas alkaline complexes) rather than to the nearby Mexican Volcanic Belt. The volcanism in this field began in late Miocene and has continued in historical times, The TVF is composed of 4 large volcanoes (San Martin Tuxtla, San Martin Pajapan, Santa Marta, Cerro El Vigia), at least 365 volcanic cones and 43 maars. In this poster we present the distribution of the maars, their size and depths. These maars span from a few hundred km to almost 1 km in average diameter, and a few meters to several tens of meters in depth; most of them filled with lakes. As an example on the nature of these structures we present our results of the ongoing study of 'Laguna Pizatal or Pisatal' (18° 33'N, 95° 16.4'W, 428 masl) located some 3 km from the village of Reforma, on the western side of San Martin Tuxtla volcano. Laguna Pisatal is a maar some 500 meters in radius and a depth about 40 meters from the surrounding ground level. It is covered by a lake 200 m2 in extent fed by a spring discharging on its western side. We examined a succession of 15 layers on the margins of the maar, these layers are blast deposits of different sizes interbedded by surge deposits. Most of the contacts between layers are irregular; which suggests scouring during deposition of the upper beds. This in turn suggests that the layers were deposited in a rapid series of explosions, which mixed juvenile material with fragments of the preexisting bedrock. We were unable to find the extent of these deposits since the surrounding areas are nowadays sugar cane plantations and the lake has overspilled in several occassions.

  15. Earth's Largest Terrestrial Landslide (The Markagunt Gravity Slide of Southwest Utah): Insights from the Catastrophic Collapse of a Volcanic Field

    Science.gov (United States)

    Hacker, D. B.; Biek, R. F.; Rowley, P. D.

    2015-12-01

    The newly discovered Miocene Markagunt gravity slide (MGS; Utah, USA) represents the largest volcanic landslide structure on Earth. Recent geologic mapping of the MGS indicates that it was a large contiguous volcanic sheet of allochthonous andesitic mudflow breccias and lava flows, volcaniclastic rocks, and intertonguing regional ash-flow tuffs that blanketed an area of at least 5000 km2 with an estimated volume of ~3000 km3. From its breakaway zone in the Tushar and Mineral Mountains to its southern limits, the MGS is over 95 km long and at least 65 km wide. The MGS consists of four distinct structural segments: 1) a high-angle breakaway segment, 2) a bedding-plane segment, ~60 km long and ~65 km wide, typically located within the volcaniclastic Eocene-Oligocene Brian Head Formation, 3) a ramp segment ~1-2 km wide where the slide cuts upsection, and 4) a former land surface segment where the upper-plate moved at least 35 km over the Miocene landscape. The presence of basal and lateral cataclastic breccias, clastic dikes, jigsaw puzzle fracturing, internal shears, pseudotachylytes, and the overall geometry of the MGS show that it represents a single catastrophic emplacement event. The MGS represents gravitationally induced collapse of the southwest sector of the Oligocene to Miocene Marysvale volcanic field. We suggest that continuous growth of the Marysvale volcanic field, loading more volcanic rocks on a structurally weak Brian Head basement, created conditions necessary for gravity sliding. In addition, inflation of the volcanic pile due to multiple magmatic intrusions tilted the strata gently southward, inducing lateral spreading of the sub-volcanic rocks prior to failure. Although similar smaller-scale failures have been recognized from individual volcanoes, the MGS represents a new class of low frequency but high impact hazards associated with catastrophic sector collapse of large volcanic fields containing multiple volcanoes. The relationship of the MGS to

  16. Geologic and geophysical investigations of the Zuni-Bandera volcanic field, New Mexico

    Science.gov (United States)

    Ander, M. E.; Heiken, G.; Eichelberger, J.; Laughlin, A. W.; Huestis, S.

    1981-05-01

    A positive, northeast-trending gravity anomaly, 90 km long and 30 km wide, extends southwest from the Zuni uplift, New Mexico. The Zuni-Bandera volcanic field, an alignment of 74 basaltic vents, is parallel to the eastern edge of the anomaly. Lavas display a bimodal distribution of tholeiitic and alkalic compositions, and were erupted over a period from 4 Myr to present. A residual gravity profile taken perpendicular to the major axis of the anomaly was analyzed using linear programming and ideal body theory to obtain bounds on the density contrast, depth, and minimum thickness of the gravity body.

  17. Effects of remote earthquakes at the Nirano Mud Volcanic Field: insights from geophysical studies

    Science.gov (United States)

    Lupi, Matteo; Kenkel, Johannes; Fuchs, Florian; Ricci, Tullio; Suski, Barbara; Conventi, Marzia; Miller, Stephen A.

    2014-05-01

    more intense signals. The excitement of these higher frequencies lasted for less than 20 minutes with possibly few locally induced microseismic events towards the end of this period. The measured response of the Nirano Mud Volcanic Field to the M4.4 earthquake (~60 km far) falls outside the empirical magnitude-vs-distance plot based on historical and qualitative data. We suggest that new quantitative data based on geophysical methods should be used to review the dynamic triggering threshold currently used for dynamic triggering studies of mud volcanic systems.

  18. Constraints on the origin and evolution of magmas in the Payún Matrú Volcanic Field, Quaternary Andean Back-arc of Western Argentina

    NARCIS (Netherlands)

    Hernando, I.R.; Aragón, E.; Frei, R.; González, P.D.; Spakman, W.|info:eu-repo/dai/nl/074103164

    2014-01-01

    The Payún Matrú Volcanic Field (Pleistocene–Holocene) is located in the Andean back-arc of the Southern Volcanic Zone, western Argentina, and is contemporaneous with the Andean volcanic arc at the same latitude. It includes two polygenetic, mostly trachytic volcanoes: Payún Matrú (with a summit

  19. Shallow Plumbing Geometry of a Monogenetic Volcano, Lunar Crater Volcanic Field, Nevada

    Science.gov (United States)

    Harp, A.; Valentine, G.

    2013-12-01

    The Lunar Crater Volcanic Field is a 90 km long, 20 km wide field of monogenetic volcanoes such as scoria cones, spatter ramparts, and maars. The most recent eruption was 38 ka indicating it is essentially an active volcanic field. Although scoria cones are relatively small, they can generate natural hazards similar to composite volcanoes, such as ballistic bombs, lava flows, and the disruption of air traffic due to tephra dispersal. Physical controls on eruptions must be identified and studied in order to develop better hazard assessments. The geometry of a scoria cone's shallow plumbing system plays a major role in determining the eruption characteristics. Numerical eruption models and hazard assessments assume simple geometric shapes such as straight-sided or flaring cylinders to represent the shape of the near-surface conduit; little field data exist to support these assumed geometries. A specific vent in the southern area of the volcanic field was selected because of its excellent erosional exposure. Field mapping and measurements were made of proximal pyroclastic deposits, intrusions including the feeder dike, and the eruption conduit. Orientated samples of clastogenic lava flows and magmatic intrusions were gathered and thin sectioned to determine magma flow vectors. The eruption began along a ~295 meter, non-linear fissure in areas now preserved as steep knobs. The fissure eruption created a complex spatter rampart that was later buried as activity focused to a single vent. The feeder dike is intermittently exposed along strike for 1 kilometer, and ranges from 1.5-2 meters wide, and in most cases sub-vertical with the exception of two small sub-horizontal sills ~20 meters long. Erosion has exposed a cross section of the eruption conduit up to 23.5 meters below paleosurface, revealing a distinct flare 15 meters below the paleo-surface and a maximum surface width of 18.3 meters. Felsic streaks, sourced from the rhyolitic country rock, along with crystal

  20. Combining probabilistic hazard assessment with cost-benefit analysis to support decision making in a volcanic crisis from the Auckland Volcanic Field, New Zealand

    Science.gov (United States)

    Sandri, Laura; Jolly, Gill; Lindsay, Jan; Howe, Tracy; Marzocchi, Warner

    2010-05-01

    One of the main challenges of modern volcanology is to provide the public with robust and useful information for decision-making in land-use planning and in emergency management. From the scientific point of view, this translates into reliable and quantitative long- and short-term volcanic hazard assessment and eruption forecasting. Because of the complexity in characterizing volcanic events, and of the natural variability of volcanic processes, a probabilistic approach is more suitable than deterministic modeling. In recent years, two probabilistic codes have been developed for quantitative short- and long-term eruption forecasting (BET_EF) and volcanic hazard assessment (BET_VH). Both of them are based on a Bayesian Event Tree, in which volcanic events are seen as a chain of logical steps of increasing detail. At each node of the tree, the probability is computed by taking into account different sources of information, such as geological and volcanological models, past occurrences, expert opinion and numerical modeling of volcanic phenomena. Since it is a Bayesian tool, the output probability is not a single number, but a probability distribution accounting for aleatory and epistemic uncertainty. In this study, we apply BET_VH in order to quantify the long-term volcanic hazard due to base surge invasion in the region around Auckland, New Zealand's most populous city. Here, small basaltic eruptions from monogenetic cones pose a considerable risk to the city in case of phreatomagmatic activity: evidence for base surges are not uncommon in deposits from past events. Currently, we are particularly focussing on the scenario simulated during Exercise Ruaumoko, a national disaster exercise based on the build-up to an eruption in the Auckland Volcanic Field. Based on recent papers by Marzocchi and Woo, we suggest a possible quantitative strategy to link probabilistic scientific output and Boolean decision making. It is based on cost-benefit analysis, in which all costs

  1. Gold-silver mining districts, alteration zones, and paleolandforms in the Miocene Bodie Hills Volcanic Field, California and Nevada

    Science.gov (United States)

    Vikre, Peter G.; John, David A.; du Bray, Edward A.; Fleck, Robert J.

    2015-09-25

    The Bodie Hills is a ~40 by ~30 kilometer volcanic field that straddles the California-Nevada state boundary between Mono Lake and the East Walker River. Three precious metal mining districts and nine alteration zones are delineated in Tertiary-Quaternary volcanic and Mesozoic granitic and metamorphic rocks that comprise the volcanic field. Cumulative production from the mining districts, Bodie, Aurora, and Masonic, is 3.4 million ounces of gold and 28 million ounces of silver. Small amounts of mercury were produced from the Potato Peak, Paramount-Bald Peak, and Cinnabar Canyon-US 395 alteration zones; a native sulfur resource in the Cinnabar Canyon-US 395 alteration zone has been identified by drilling. There are no known mineral resources in the other six alteration zones, Red Wash-East Walker River, East Brawley Peak, Sawtooth Ridge, Aurora Canyon, Four Corners, and Spring Peak. The mining districts and alteration zones formed between 13.4 and 8.1 Ma in predominantly ~15–9 Ma volcanic rocks of the Bodie Hills volcanic field. Ages of hydrothermal minerals in the districts and zones are the same as, or somewhat younger than, the ages of volcanic host rocks.

  2. Investigating the consequences of urban volcanism using a scenario approach I: Development and application of a hypothetical eruption in the Auckland Volcanic Field, New Zealand

    Science.gov (United States)

    Deligne, Natalia I.; Fitzgerald, Rebecca H.; Blake, Daniel M.; Davies, Alistair J.; Hayes, Josh L.; Stewart, Carol; Wilson, Grant; Wilson, Thomas M.; Castelino, Renella; Kennedy, Ben M.; Muspratt, Scott; Woods, Richard

    2017-04-01

    What happens when a city has a volcanic eruption within its boundaries? To explore the consequences of this rare but potentially catastrophic combination, we develop a detailed multi-hazard scenario of an Auckland Volcanic Field (AVF) eruption; the AVF underlies New Zealand's largest city, Auckland. We start with an existing AVF unrest scenario sequence and develop it through a month-long hypothetical eruption based on geologic investigations of the AVF and historic similar eruptions from around the world. We devise a credible eruption sequence and include all volcanic hazards that could occur in an AVF eruption. In consultation with Civil Defence and Emergency Management staff, we create a series of evacuation maps for before, during, and after the hypothetical eruption sequence. Our result is a versatile scenario with many possible applications, developed further in companion papers that explore eruption consequences on transportation and water networks. However, here we illustrate one application: evaluating the consequences of an eruption on electricity service provision. In a collaborative approach between scientists and electricity service providers, we evaluate the impact of the hypothetical eruption to electricity generation, transmission, and distribution infrastructure. We then evaluate how the impacted network functions, accounting for network adaptations (e.g., diverting power away from evacuated areas), site access, and restoration factors. We present a series of regional maps showing areas with full service, rolling outages, and no power as a result of the eruption. This illustrative example demonstrates how a detailed scenario can be used to further understand the ramifications of urban volcanism on local and regional populations, and highlights the importance of looking beyond damage to explore the consequences of volcanism.

  3. Multiple episodes of hydrothermal activity and epithermal mineralization in the southwestern Nevada volcanic field and their relations to magmatic activity, volcanism and regional extension

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, S.I.; Noble, D.C.; Jackson, M.C. [Univ. of Nevada, Reno, NV (United States)] [and others

    1994-12-31

    Volcanic rocks of middle Miocene age and underlying pre-Mesozoic sedimentary rocks host widely distributed zones of hydrothermal alteration and epithermal precious metal, fluorite and mercury deposits within and peripheral to major volcanic and intrusive centers of the southwestern Nevada volcanic field (SWNVF) in southern Nevada, near the southwestern margin of the Great Basin of the western United States. Radiometric ages indicate that episodes of hydrothermal activity mainly coincided with and closely followed major magmatic pulses during the development of the field and together spanned more than 4.5 m.y. Rocks of the SWNVF consist largely of rhyolitic ash-flow sheets and intercalated silicic lava domes, flows and near-vent pyroclastic deposits erupted between 15.2 and 10 Ma from vent areas in the vicinity of the Timber Mountain calderas, and between about 9.5 and 7 Ma from the outlying Black Mountain and Stonewall Mountain centers. Three magmatic stages can be recognized: the main magmatic stage, Mountain magmatic stage (11.7 to 10.0 Ma), and the late magmatic stage (9.4 to 7.5 Ma).

  4. Geochemical and geophysical monitoring activities in Campo de Calatrava Volcanic Field (Spain)

    Science.gov (United States)

    Luengo-Oroz, Natividad; Villasante-Marcos, Víctor; López-Díaz, Rubén; Calvo, Marta; Albert, Helena; Domínguez Cerdeña, Itahiza

    2017-04-01

    The Campo de Calatrava Volcanic Field (CCVF) or Spanish Central Volcanic Zone is located in central continental Spain (Ciudad Real province) and covers about 5000 km2. It includes around 240 eruptive centers, mainly monogenetic basaltic cones but also explosive maar structures. According to K-Ar geochronology, its main activity phase occurred during Pliocene and Pleistocene epochs (between 5 and 1.7 Ma) and involved alkaline to ultraalkaline magmas, although an older ultrapotassic phase is dated around 8.7-6.4 Ma. However, some recent works have proposed Holocene ages for some of the volcanic products, opening the possibility of considering the CCVF "active" according to international standards. Responding to this situation, the Instituto Geográfico Nacional (IGN) has initiated geochemical and geophysical monitoring activities in the CCVF. Here, we describe these ongoing efforts and we report results about groundwater geochemistry at several natural highly-gaseous springs in the area (hervideros), as well as soil temperature, CO2 diffuse flux from the soil and electrical self-potential data mapped on a small degassing structure called La Sima. In order to analyze microseismicity or any seismic anomaly in the CCVF, a seismic station has also been installed close to this degassing structure. Physicochemical parameters (temperature, pH, Eh and electric conductivity) were measured in situ in four springs and samples were taken in order to analyze major ions and trace elements. Total composition of dissolved gases and helium isotopic ratios were also determined. To complete soil temperature, self-potential and gas prospections performed in La Sima, soil gases were sampled at the bottom of the structure at a depth of 20 cm. Analysis of the total gas composition found 957400 ppm of CO2. Low values of O2 and N2 were also detected (5600 and 24800 ppm respectively).

  5. Variability of the 0-3 Ma palaeomagnetic field observed from the Boring Volcanic Field of the Pacific Northwest

    Science.gov (United States)

    Lhuillier, Florian; Shcherbakov, Valeriy P.; Gilder, Stuart A.; Hagstrum, Jonathan T.

    2017-10-01

    The Boring Volcanic Field of the Pacific Northwest (USA), composed of more than 80 eruptive units ranging in age from 3200 to 60 ka, offers a unique possibility to investigate the variability of the Quaternary to late Neogene palaeomagnetic field. To complement previous work on palaeodirections, we conducted 240 absolute palaeointensity (API) experiments with the joint use of the continuous (Wilson) and stepwise (Thellier-Coe) double-heating protocol, along with 620 relative palaeointensity (RPI) experiments based on the pseudo-Thellier approach. We successfully determined absolute estimates for 12 independent eruptive units, as well as relative estimates for 47 out of 132 investigated sites. We compare these results with the existing database for the last 3 Myr and obtain an estimate of the relative variability in palaeointensity on the order of 40-45 per cent as a proxy for palaeosecular variation. API and RPI data suggest a possible asymmetry between normal and reverse polarities.

  6. The correlation between geomagnetic field reversals, Hawaiian volcanism, and the motion of the Pacific plate

    Directory of Open Access Journals (Sweden)

    W. Dong

    1996-06-01

    Full Text Available The correlation between geomagnetic field reversals and volcanism is investigated, according to the speculated consequence on volcanoes of the transient electric currents in the geodynamo, through Joule's heating, before and after every reversal event. We evaluate the temporal variation during the last ~ 70 Ma both of the magma emplacement rate Q(t from the Hawaii hot spot, and of the speed v(t of the Pacific plate, by means of the observed volumes of islands and seamounts along the Hawaii/Emperor Seamounts chain, and their respective radiometric datings. Results confirm expectations. A justification of the volcanic crises that lead to the generation of the large igneous provinces during the last ~ 250 Ma also emerged. We describe in detail the complex pattern of the timings of the different effects. Joule's power is generally responsible for ~ 75-80% of magmatism, and friction power only for ~ 20-25%; but, on some occasions almost ~ 100% is fuelled by friction alone. The visco-elastic coupling between lithosphere and asthenosphere results ~ 96% viscous, and ~ 4% elastic.

  7. Geology of the Mid-Miocene Rooster Comb Caldera and Lake Owyhee Volcanic Field, eastern Oregon: Silicic volcanism associated with Grande Ronde flood basalt

    Science.gov (United States)

    Benson, Thomas R.; Mahood, Gail A.

    2016-01-01

    The Lake Owyhee Volcanic Field (LOVF) of eastern Oregon consists of rhyolitic caldera centers and lava fields contemporaneous with and spatially related to Mid-Miocene Columbia River flood basalt volcanism. Previous studies delineated two calderas in the southeastern part of LOVF near Owyhee Reservoir, the result of eruptions of two ignimbrites, the Tuff of Leslie Gulch and the Tuff of Spring Creek. Our new interpretation is that these two map units are differentially altered parts of a single ignimbrite produced in a major phreatomagmatic eruption at ~ 15.8 Ma. Areas previously mapped as Tuff of Spring Creek are locations where the ignimbrite contains abundant clinoptilolite ± mordenite, which made it susceptible to erosion. The resistant intracaldera Tuff of Leslie Gulch has an alteration assemblage of albite ± quartz, indicative of low-temperature hydrothermal alteration. Our new mapping of caldera lake sediments and pre- and post-caldera rhyolitic lavas and intrusions that are chemically similar to intracaldera Tuff of Leslie Gulch point to a single ~ 20 × 25 km caldera, which we name the Rooster Comb Caldera. Erosion of the resurgently uplifted southern half of the caldera created dramatic exposures of intracaldera Tuff of Leslie Gulch cut by post-caldera rhyolite dikes and intrusions that are the deeper-level equivalents of lava domes and flows that erupted into the caldera lake preserved in exposures to the northeast. The Rooster Comb Caldera has features in common with more southerly Mid-Miocene calderas of the McDermitt Volcanic Field and High Rock Caldera Complex, including formation in a basinal setting shortly after flood basalt eruptions ceased in the region, and forming on eruption of peralkaline ignimbrite. The volcanism at Rooster Comb Caldera postdates the main activity at McDermitt and High Rock, but, like it, begins ~ 300 ky after flood basalt volcanism begins in the area, and while flood basalts don't erupt through the silicic focus, are

  8. Jurassic ash-flow sheets, calderas, and related intrusions of the Cordilleran volcanic arc in southeastern Arizona: implications for regional tectonics and ore deposits

    Science.gov (United States)

    Lipman, P.W.; Hagstrum, J.T.

    1992-01-01

    Volcanologic, petrologic, and paleomagnetic studies of widespread Jurassic ash-flow sheets in the Huachuca-southern Dragoon Mountains area have led to identification of four large source calderas and associated comagnetic intracaldera intrusions. Stratigraphic, facies, and contact features of the caldera-related tuffs also provide constraints on the locations, lateral displacements, and very existence for some major northwest-trending faults and inferred regional thrusts in southeastern Arizona. Silicic alkalic compositions of the Jurassic caldera-related, ash-flow tuffs; bimodal associated mafic magmatism; and interstratified coarse sedimentary deposits provide evidence for synvolcanic extension and rifting within the Cordilleran magmatic arc. Gold-copper mineralization is associated with subvolcanic intrusions at several of the Jurassic calderas. -from Authors

  9. Geology and K-Ar dating of the Tuxtla Volcanic Field, Veracruz, Mexico

    Science.gov (United States)

    Nelson, Stephen A.; Gonzalez-Caver, Erika

    1992-12-01

    The Tuxtla Volcanic Field (TVF) is located on the coast of the Gulf of Mexico in the southern part of the state of Veracruz, Mexico. Volcanism began about 7 my ago, in the Late Miocene, and continued to recent times with historical eruptions in ad 1664 and 1793. The oldest rocks occur as highly eroded remnants of lava flows in the area surrounding the historically active cone of San Martín Tuxtla. Between about 3 and 1 my ago, four large composite volcanoes were built in the eastern part of the area. Rocks from these structures are hydrothermally altered and covered with lateritic soils, and their northern slopes show extensive erosional dissection that has widened preexisting craters to form erosional calderas. The eastern volcanoes are composed of alkali basalts, hawaiites, mugearites, and benmoreites, with less common calc-alkaline basaltic andesites and andesites. In the western part of the area, San Martín Tuxtla Volcano and its over 250 satellite cinder cones and maars produced about 120 km3 of lava over the last 0.8 my. A ridge of flank cinder cones blocked drainage to the north to form Laguna Catemaco. Lavas erupted from San Martín and its flank vents are restricted to compositions between basanite and alkali basalt. The alignment of major volcanoes and flank vents along a N55°W trend suggests an extensional stress field in the crust with a minimum compressional stress orientation of N35° E. In total, about 800 km3 of lava has been erupted in the TVF in the last 7 my. This gives a magma output rate of about 0.1 km3/1000 year, a value smaller than most composite cones, but similar to cinder cone fields that occur in central Mexico. Individual eruptions over the last 5000 years had volumes on the order of 0.1km3, with average recurrence intervals of 600 years. The alkaline compositions of the TVF lavas contrast markedly with the calc-alkaline compositions erupted in the subduction-related Mexican Volcanic Belt to the west, leading previous workers to

  10. Pliocene to late Pleistocene magmatism in the Aurora Volcanic Field, Nevada and California, USA

    Science.gov (United States)

    Kingdon, S.; Cousens, B.; John, D. A.; du Bray, E. A.

    2013-12-01

    The 3.9- 0.1 Ma Aurora Volcanic Field (AVF) covers 325 km2 east and southeast of the Bodie Hills, north of Mono Lake, California, USA. The AVF is located immediately northwest of the Long Valley magmatic system and adjacent and overlapping the Miocene Bodie Hills Volcanic Field (BHVF). Rock types range from trachybasalt to trachydacite, and high-silica rhyolite. The trachybasalts to trachydacites are weakly to moderately porphyritic (1-30%) with variable phenocryst assemblages that are some combination of plagioclase, hornblende, clinopyroxene, and lesser orthopyroxene, olivine, and/or biotite. Microphenocrysts are dominated by plagioclase, and include opaque oxides, clinopyroxene, and apatite. These rocks are weakly to strongly devitrified. The high-silica rhyolites are sparsely porphyritic with trace to 10% phenocrysts of quartz, sanidine, plagioclase, biotite, (+/- hornblende), accessory opaque oxide minerals, titanite, allanite, (+/-apatite, zircon), and have glassy groundmasses. Rocks in the AVF are less strongly porphyritic than those of BHVF. Plagioclase phenocrysts are often oscillatory zoned and many have sieve texture. Amphiboles have distinct black opaque rims. Xenocrystic quartz and plagioclase are rare. AVF lavas have bimodal SiO2 compositions, ranging from 49 to 78 wt%, with a gap between 65 and 75 wt%. They are high-K calc-alkaline to shoshonitic in composition, and are metaluminous to weakly peraluminous. They are enriched in rare earth elements (REE), especially light REEs, compared to the Miocene BHVF rocks. Primordial mantle-normalized incompatible element patterns show arc- or subduction-related signatures, with enrichment in Ba and Pb, and depletion in Nb and Ta. Enrichment in K and Sr and depletion in Ti are less pronounced than in the BHVF rocks. There is no correlation between lead isotope ratios and silica (initial 206Pb/204Pb ratios range from 18.974 to 19.151). Neodymium isotope ratios show a moderate negative correlation with silica

  11. Petrology of the alkaline rocks of the Macau Volcanic Field, NE Brazil

    Science.gov (United States)

    Ngonge, Emmanuel Donald; de Hollanda, Maria Helena Bezerra Maia; Pimentel, Márcio Martins; de Oliveira, Diógenes Custódio

    2016-12-01

    The Macau Volcanic Field (MVF) in the Borborema Province, NE Brazil, contains multiple centres of volcanic activity of Early to Late Cenozoic ages. We present element and Sr-Nd-Pb isotope geochemical data for four of the few most prominent basalt types of this volcanic field: Serrote Preto-type, Serra Aguda-type, Pico do Cabugi-type and Serra Preta-type, in order to assess their magmatic history from source to crystallization and the evolution of the mantle beneath the Borborema Province. The basalts are basically sodic nephelinitic-basanitic-alkali olivine basalts enriched in LILE and in Nb-Ta. The Serra Preta, Cabugi and Serra Aguda types demonstrate compositions close to primitive characteristics with 10% < MgO < 15 wt.% and 200 ppm < Ni < 500 ppm, and experienced limited fractional crystallization of olivine-clinopyroxene-plagioclase-oxides with negligible wall-rock assimilation. Rb/Sr and Ba/Rb constraints support the generation of SiO2-undersaturated magmas from mantle melting of amphibole-bearing peridotites with minor phlogopite. The source for the basanites and alkali basalts is estimated to be a garnet-bearing domain around the lithosphere-asthenosphere boundary (80-93 km deep), while the nephelinites are derived from the adiabatic asthenosphere at 105 km with temperatures of 1480 °C. Their incompatible trace element patterns and Sr-Nd-Pb isotopic compositions are similar to FOZO and EM-type OIB magmas. From the comparison of data with those of the Ceará-Mirim dyke swarm we propose that there is a ubiquitous FOZO reservoir in the SCLM beneath the Borborema Province. This FOZO signature characterized the upwelling asthenosphere during the lithospheric extension and thinning at the opening of the Equatorial Atlantic and is clearly represented in the Mesozoic olivine tholeiites of Ceará-Mirim. The upwelled asthenosphere cooled as a rigid SCLM since the Cretaceous and has preserved its FOZO signature evident in the Macau Cenozoic basalts. The EM signatures

  12. New Contributions to the Geomagnetic Instability Time Scale: Paleomagnetic study of Tequila and Ceboruco-San Pedro-Amado Nervo Volcanic Fields (Trans Mexican Volcanic Belt)

    Science.gov (United States)

    Rodriguez Ceja, M.; Gogichaishvili, A.; Alva-Valdivia, L.; Rosas Elguera, J.; Calvo, M.; Urrutia-Fucugauchi, J.

    2005-05-01

    The Trans-Mexican Volcanic Belt (TMVB) is one of the largest continental volcanic arcs of the North American plate. It spans about 1000 km from the Pacific to the Gulf of Mexico. Despite the abundance of thick lava sequences with quite high extrusion rates, the TMVB have been relatively little studied from a paleomagnetic point of view. Previous studies were aimed for tectonic evolution of the region rather than documenting fluctuations of Earth's magnetic field in terms of both directions and intensity. We report a detailed paleomagnetic and rock-magnetic study of Tequila and Ceboruco-San Pedro-Amado Nervo volcanic fields. 350 oriented samples belonging to 31 independent cooling units were collected. All these sites were previously dated by means of the state-of-the-art 40Ar-39Ar geochronological method and span from 1.1 Ma to 2 Ky. Rock-magnetic experiments which included continuous susceptibility, isothermal remanence acquisition and hysteresis measurements point to simple magnetic mineralogy. In most of cases, the remanence is carried by Ti-poor titanomagnetite of pseudo-single-domain magnetic structure. The paleodirections of the flow dated as 819±25 ka correspond to a VGP latitude of 18° N. This anomalous field behaviour apparently recorded prior to the Matuyama-Brunhes reversal may coincide with the geomagnetic event, defined as M-B precursor. Two independent lava flows, dated as 623±91 and 614±16 ka respectively, yield reverse paleodirections and one lava flow dated as 690±29 yields transitional paleodirections. It is possible that these lavas erupted during the worldwide observable Big Lost or Delta events.

  13. Peralkaline ash flow tuffs and calderas of the McDermitt volcanic field, southeast Oregon and north central Nevada.

    Science.gov (United States)

    Rytuba, J.J.; McKee, E.H.

    1984-01-01

    This volcanic field covers an area of 20 000 km2 and consists of seven large-volume ash-flow sheets that vented 16.1-15 m.y. ago. The volcanic field is characterized by peralkaline, high-silica rhyolite, and all but one of the sheets are comendites. Each ash-flow sheet resulted in the formation of a large collapse caldera. Thickening of the ash-flow sheets, monoclinal warping outside the caldera ring-fault and tilting-in towards the caldera of blocks bounded by curvilinear faults all indicate regional subsidence prior to caldera collapse. The McDermitt caldera complex is highly mineralized; it contains ore deposits of Hg, Sb, Cs, Li and U. The peralkaline tuffs have high contents of these elements and were the source rocks from which metals were leached by hydrothermal systems developed during the last stage of caldera-related volcanism. (Following abstract) -W.H.B.

  14. Evidence for gas and magmatic sources beneath the Yellowstone volcanic field from seismic tomographic imaging

    Science.gov (United States)

    Husen, Stephan; Smith, Robert B.; Waite, Gregory P.

    2004-03-01

    The 3-D P-wave velocity and P- to S-wave velocity ratio structure of the Yellowstone volcanic field, Wyoming, has been determined from local earthquake tomography using new data from the permanent Yellowstone seismic network. We selected 3374 local earthquakes between 1995 and 2001 to invert for the 3-D P-wave velocity ( Vp) and P-wave to S-wave velocity ratio ( Vp/ Vs) structure. Vp anomalies of small size (15×15 km) are reliably imaged in the northwestern part of the model outside the Yellowstone caldera; inside the caldera only Vp anomalies of large size extending over several grid nodes are reliably imaged. The Vp/ Vs solution is generally poorer due to the low number of S-P arrival times. Only the northwestern part of the model is resolved with confidence; the Vp/ Vs solution also suffers from strong vertical and horizontal velocity smearing. The tomographic images confirm the existence of a low Vp-body beneath the Yellowstone caldera at depths greater than 8 km, possibly representing hot, crystallizing magma. The most striking result of our study is a volume of anomalously low Vp and Vp/ Vs in the northwestern part of the Yellowstone volcanic field at shallow depths of <2.0 km. Theoretical calculations of changes in P- to S-wave velocity ratios indicate that these anomalies can be interpreted as porous, gas-filled rock. The close spatial correlation of the observed anomalies and the occurrence of the largest earthquake swarm in historic time in Yellowstone, 1985, suggest that the gas may have originated as part of magmatic fluids released by crystallization of magma beneath the Yellowstone caldera.

  15. Postglacial eruptive history of Laguna del Maule volcanic field in Chile, from fallout stratigraphy in Argentina

    Science.gov (United States)

    Fierstein, J.; Sruoga, P.; Amigo, A.; Elissondo, M.; Rosas, M.

    2012-12-01

    The Laguna del Maule (LdM) volcanic field, which surrounds the 54-km2 lake of that name, covers ~500 km2 of rugged glaciated terrain with Quaternary lavas and tuffs that extend for 40 km westward from the Argentine frontier and 30 km N-S from the Rio Campanario to Laguna Fea in the Southern Volcanic Zone of Chile. Geologic mapping (Hildreth et al., 2010) shows that at least 130 separate vents are part of the LdM field, from which >350 km3 of products have erupted since 1.5 Ma. These include a ring of 36 postglacial rhyolite and rhyodacite coulees and domes that erupted from 24 separate vents and encircle the lake, suggesting a continued large magma reservoir. Because the units are young, glassy, and do not overlap, only a few ages had been determined and the sequence of most of the postglacial eruptions had not previously been established. However, most of these postglacial silicic eruptions were accompanied by explosive eruptions of pumice and ash. Recent investigations downwind in Argentina are combining stratigraphy, grain-size analysis, chemistry, and radiocarbon dating to correlate the tephra with eruptive units mapped in Chile, assess fallout distribution, and establish a time-stratigraphic framework for the postglacial eruptions at Laguna del Maule. Two austral summer field seasons with a tri-country collaboration among the geological surveys of the U.S., Chile, and Argentina, have now established that a wide area east of the volcanic field was blanketed by at least 3 large explosive eruptions from LdM sources, and by at least 3 more modest, but still significant, eruptions. In addition, an ignimbrite from the LdM Barrancas vent complex on the border in the SE corner of the lake traveled at least 15 km from source and now makes up a pyroclastic mesa that is at least 40 m thick. This ignimbrite (72-75% SiO2) preceded a series of fall deposits that are correlated with eruption of several lava flows that built the Barrancas complex. Recent 14C dates suggest

  16. Geochemistry of intrusive rocks associated with the Latir volcanic field, New Mexico, and contrasts between evolution of plutonic and volcanic rocks

    Science.gov (United States)

    Johnson, C.M.; Czamanske, G.K.; Lipman, P.W.

    1989-01-01

    Plutonic rocks associated with the Latir volcanic field comprise three groups: 1) ???25 Ma high-level resurgent plutons composed of monzogranite and silicic metaluminous and peralkaline granite, 2) 23-25 Ma syenogranite, and alkali-feldspar granite intrusions emplaced along the southern caldera margin, and 3) 19-23 Ma granodiorite and granite plutons emplaced south of the caldera. Major-element compositions of both extrusive and intrusive suites in the Latir field are broadly similar; both suites include high-SiO2 rocks with low Ba and Sr, and high Rb, Nb, Th, and U contents. Moreover, both intermediateto siliciccomposition volcanic and plutonic rocks contain abundant accessory sphene and apatite, rich in rare-earth elements (REE), as well as phases in which REE's are essential components. Strong depletion in Y and REE contents, with increasing SiO2 content, in the plutonic rocks indicate a major role for accessory mineral fractionation that is not observed in volcanic rocks of equivalent composition. Considerations of the rheology of granitic magma suggest that accessory-mineral fractionation may occur primarily by filter-pressing evolved magmas from crystal-rich melts. More limited accessory-mineral crystallization and fractionation during evolution of the volcanic magmas may have resulted from markedly lower diffusivities of essential trace elements than major elements. Accessory-mineral fractionation probably becomes most significant at high crystallinities. The contrast in crystallization environments postulated for the extrusive and intrusive rocks may be common to other magmatic systems; the effects are particularly pronounced in highly evolved rocks of the Latir field. High-SiO2 peralkaline porphyry emplaced during resurgence of the Questa caldera represents non-erupted portions of the magma that produced the Amalia Tuff during caldera-forming eruption. The peralkaline porphyry continues compositional and mineralogical trends found in the tuff. Amphibole

  17. Field Courses for Volcanic Hazards Mapping at Parícutinand Jorullo Volcanoes (Mexico)

    Science.gov (United States)

    Victoria Morales, A.; Delgado Granados, H.; Roberge, J.; Farraz Montes, I. A.; Linares López, C.

    2007-05-01

    During the last decades, Mexico has suffered several geologic phenomena-related disasters. The eruption of El Chichón volcano in 1982 killed >2000 people and left a large number of homeless populations and severe economic damages. The best way to avoid and mitigate disasters and their effects is by making geologic hazards maps. In volcanic areas these maps should show in a simplified fashion, but based on the largest geologic background possible, the probable (or likely) distribution in time and space of the products related to a variety of volcanic processes and events, according to likely magnitude scenarios documented on actual events at a particular volcano or a different one with similar features to the volcano used for calibration and weighing geologic background. Construction of hazards maps requires compilation and acquisition of a large amount of geological data in order to obtain the physical parameters needed to calibrate and perform controlled simulation of volcanic events under different magnitude-scenarios in order to establish forecasts. These forecasts are needed by the authorities to plan human settlements, infrastructure, and economic development. The problem is that needs are overwhelmingly faster than the adjustments of university programs to include courses. At the Earth Science División of the Faculty of Engineering at the Universidad Nacional Autónoma de México, the students have a good background that permits to learn the methodologies for hazards map construction but no courses on hazards evaluations. Therefore, under the support of the university's Program to Support Innovation and Improvement of Teaching (PAPIME, Programa de Apoyo para la Innovación y Mejoramiento de la Enseñanza) a series of field-based intensive courses allow the Earth science students to learn what kind of data to acquire, how to record, and process in order to carry out hazards evaluations. This training ends with hazards maps that can be used immediately by the

  18. Geochemistry and petrogenesis of the Gallego Volcanic Field, Solomon Islands, SW Pacific and geotectonic implications

    Science.gov (United States)

    Petterson, M. G.; Haldane, M. I.; Smith, D. J.; Billy, D.; Jordan, N. J.

    2011-08-01

    The Upper Miocene to present day Gallego Volcanic Field (GVF) is located in northwest Guadalcanal, Solomon Islands, SW Pacific, and potentially includes the offshore Savo volcano. The GVF is a multi-centred complex covering an area of ~ 800 km 2 on Guadalcanal and a further ~ 30 km 2 on the island of Savo, north of west Guadalcanal. GVF volcanism is characterised by effusive eruptions of lava, intrusion of sub-volcanic plutons, as well as pyroclastic flow and fall deposits dominated by block and ash flow deposits. Geochemical analysis of a representative suite of samples from the GVF demonstrates that the GVF comprise largely a 'main suite' of basalts to andesites and minor trachyandesites. The predominant mineralogy of the GVF comprises plagioclase, amphibole, clinopyroxene and magnetite-ilmenite. Associated with the 'main suite' are cognate nodules composed of hornblendite, gabbros, and clinopyroxenite. Interpretation of major and trace element geochemistry and petrographic studies suggests that fractionation was dominated by early clinopyroxene, and later amphibole + clinopyroxene + minor plagioclase. Geochemical features such as the incompatibility of Sr suggest that plagioclase largely crystallised en-masse late in the fractionation sequence. The presence of amphibole and late fractionation of plagioclase is suggestive of derivation from initially water-rich magmas. The region is characterised by strong geographically-related geochemical variations as evidenced by the Woodlark (and Manus) basins: basalts become more arc-like within the ocean basins with decreasing distance to the subducting trench. The GVF-Savo volcanoes are spatially and geochemically affected by deep N-S fractures that show some evidence of sympathetic geochemical variations with distance from the trench (e.g. Sr/Y ratios). Comparison with a range of international data for Th/Nb vs Pb/Nb and Dy/Yb vs SiO 2 indicate that: amphibole was indeed a strong controlling phase on magmatic evolution

  19. Age and petrology of the Tertiary As Sarat volcanic field, southwestern Saudi Arabia

    Science.gov (United States)

    du Bray, E.A.; Stoeser, D.B.; McKee, E.H.

    1991-01-01

    Harrat As Sarat forms the second smallest and southernmost of the basalt fields of western Saudi Arabia and is part of a voluminous Red Sea rift-related continental alkali basalt province. The rocks of the As Sarat were emplaced during the first stage of Red Sea rifting and represent the northernmost extension of the Tertiary Trap Series volcanics that occur mainly in the Yemen Arab Republic and Ethiopia. The field consists of up to 580 m of basalt flows, that are intruded by basaltic plugs, necks, minor dikes, and highly evolved peralkaline trachyte intrusions. K-Ar ages indicate that the As Sarat field formed between 31 and 22 Ma and contains an eruption hiatus of one million years that began about 25 Ma ago. Pre-hiatus flows are primarily hypersthene normative intersertal subalkaline basalt, whereas the majority of post-hiatus flows are nepheline normative alkali basalt and hawaiite with trachytic textures. Normative compositions of the basalts are consistent with their genesis by partial melting at varying depths. Trace element abundances in the basalt indicate that varying degrees of partial melting and fractional crystallization (or crystal accumulation) had major and minor roles, respectively, in development of compositional variation in these rocks. Modeling indicates that the pre-hiatus subalkaline basalts represent 8-10 percent mantle melting at depths of about 70 km and the post-hiatus alkali basalts represent 4-9 percent mantle melting at depths greater than 70 km. ?? 1991.

  20. North Qorveh volcanic field, western Iran: eruption styles, petrology and geological setting

    Science.gov (United States)

    Asiabanha, Abbas; Bardintzeff, Jacques-Marie; Veysi, Sara

    2017-11-01

    In the metamorphic Sanandaj-Sirjan Zone of western Iran, the "North Qorveh Volcanic Field" is constituted by Pleistocene scoria cones and associated deposits. Most scoria cones in the area display a simple structure resulted by Strombolian eruptions. Some of them are more complex, such as the Kuh-e Qarineh cone in where basaltic scoriaceous falls are underlain by felsic pyroclastic density-current deposits due to gas streaming at the base of eruption columns and are overlain by basaltic lava flows linked to basaltic fire fountains. Thus, it seems that the latter cones have been likely constructed by more or less violent Strombolian and then Hawaiian activities. Two types of enclaves have been found: gneissic xenoliths scavenged from the metamorphic basement and ultramafic-mafic (37-47 wt% SiO2) cumulates with the same paragenesis as the basaltic scoriaceous falls and lava flows. Three classes of cumulates were identified: (1) apatite mica hornblendite; (2) apatite hornblendite; and (3) olivine biotitite. Moreover, the mineral assemblage of basaltic rocks in the area (olivine (Fo79 - 83) + diopside + pargasite + phlogopite + Fe-Ti oxides ± plagioclase ± apatite) is very similar to lamprophyric facies. So, it seems that the parental magma was originated by mantle metasomatism. Although the felsic pyroclastic density-current deposits show a calcalkaline trend, the whole-rock and mineral chemistry of the basaltic rocks in the area imply an alkaline affinity. Also, the samples show subduction and continental collision signatures. Thus, the alkaline composition of this young volcanic centre in a metamorphic terrain could be explained by descending slab-break off and reactivation of small-scale convection at the lithosphere-asthenosphere boundary.

  1. Managing a Monogenetic Volcanic Field As a World Heritage Nomination: Implications for Science, Outreach, and Hazards

    Science.gov (United States)

    Olive-Garcia, C.; van Wyk de Vries, B.

    2014-12-01

    Monogenetic volcanoes form a large proportion of the world's volcanoes. They are in all tectonic environments and thus provide a significant link to understand fundamental geological processes such as plate tectonics. The Chaîne des Puys - Limagne fault World Heritage nomination is a prime example of this link where monogenetic volcanism, continental rifting, uplift and erosion are highlighted, and are made understandable to the lay person, though the actions on over 80 aligned monogenetic volcanoes. Such geoheritage is essential for monogenetic and other geological risks to be communicated to the wider public. The current scientific interest on monogenetic volcanoes is quite recent, and because of this, and probably their global distribution but small size, they have not received their due importance from a geoheritage standpoint. Some individual sites and some fields are protected and developed as attractions, but there has been no coherent global strategy for defining monogenetic heritage, or for linking sites. This is starting through the monogenetic commission of IAVCEI, and with wider participation of the IUGS and other bodies. The Chaîne des Puys - Limagne Fault UNESCO project is an example of how public awareness, at a global scale, and be increased through geoheritage. This is done integrating local stakeholders: population, industry, science, landscapers, artists, sports, government. This builds on existing protection and sustainable activities, integrating them with education programs. The result is to create a populace that 'thinks geological', and which leads visitors to also become geologically aware. This is helped by a monogenetic landscape that is easily readable and by links made to other geological sites around the world. We will explain how this process is ongoing. The project started over 35 years ago, and is a long-term vision to develop geological understanding and protection of this unique monogenetic and tectono-volcanic site.

  2. Arizona transportation history.

    Science.gov (United States)

    2011-12-01

    The Arizona transportation history project was conceived in anticipation of Arizonas centennial, which will be : celebrated in 2012. Following approval of the Arizona Centennial Plan in 2007, the Arizona Department of : Transportation (ADOT) recog...

  3. Compositional variation of lavas from a young volcanic field on the Southern Mid-Atlantic Ridge, 8°48'S

    Science.gov (United States)

    Haase, K.; Brandl, P. A.; Melchert, B.; Hauff, F.; Garbe-Schoenberg, C.; Paulick, H.; Kokfelt, T. F.; Devey, C. W.

    2012-12-01

    Volcanic eruptions along the mid-oceanic ridge system are the most abundant signs of volcanic activity on Earth but little is known about the timescales and nature of these processes. The main parameter determining eruption frequency as well as magma composition appears to be the spreading rate of the mid-oceanic ridge. However, few observations on the scale of single lava flows exist from the slow-spreading Mid-Atlantic Ridge so far. Here we present geological observations and geochemical data for the youngest volcanic features of the so-called A2 segment (Bruguier et al., 2003, Hoernle et al., 2011) of the slow-spreading (33 mm/yr) southern Mid-Atlantic Ridge at 8°48'S. This segment has a thickened crust of about 9 km indicating increased melt production in the mantle. Side-scan sonar mapping revealed a young volcanic field with high reflectivity that was probably erupted from two volcanic fissures each of about 3 km length. Small-scale sampling of the young lava field at 8°48'S by ROV and wax corer and geochemical analyses of the volcanic glasses reveal three different compositional lava units along this about 11 km long portion of the ridge. Based on the incompatible element compositions of volcanic glasses (e.g. K/Ti, Ce/Yb) we can distinguish two lava units forming the northern and the larger southern part of the lava field covering areas of about 5 and 9 square kilometres, respectively. Basalts surrounding the lava field and from an apparently old pillow mound within the young flows are more depleted in incompatible elements than glasses from the young volcanic field. Radium disequilibria suggest that most lavas from this volcanic field have ages of 3000 to 5000 yrs whereas the older lavas surrounding the lava field are older than 8000 yrs. Faults and a thin sediment cover on many lavas support the ages and indicate that this part of the Mid-Atlantic Ridge is in a tectonic rather than in a magmatic stage. Lavas from the northern and southern ends of the

  4. Igneous activity and related ore deposits in the western and southern Tushar Mountains, Marysvale volcanic field, west-central Utah

    Science.gov (United States)

    Steven, Thomas A.

    1984-01-01

    PART A: Igneous activity in the Marysvale volcanic field of western Utah can be separated into many episodes of extrusion, intrusion, and hydrothermal activity. The rocks of the western Tushar Mountains, near the western part of the volcanic field, include intermediate-composition, calc-alkalic volcanic rocks erupted from scattered volcanoes in Oligocene through earliest Miocene time and related monzonitic intrusions emplaced 24-23 m.y. ago. Beginning 22-21 m.y. ago and extending through much of the later Cenozoic, a bimodal basalt-rhyolite assemblage was erupted widely throughout the volcanic field. Only volcanic and intrusive rocks belonging to the rhyolitic end member of this bimodal assemblage are present in the western Tushar Mountains; most of these rocks either fill the Mount Belknap caldera (19 m.y. old) or are part of the rhyolite of Gillies Hill (9---8 m.y. old). Episodic hydrothermal activity altered and mineralized rocks at many places in the western Tushar Mountains during Miocene time. The earliest activity took place in and adjacent to monzonitic calcalkalic intrusions emplaced in the vicinity of Indian Creek and Cork Ridge. These rocks were widely propylitized, and gold-bearing quartz-pyrite-carbonate veins formed in local fractures. Hydrothermal activity associated with the Mount Belknap caldera mobilized and redeposited uranium contained in the caldera-fill rocks and formed primary concentrations of lithophile elements (including molybdenum and uranium) in the vicinity of intrusive bodies. Hydrothermal activity associated with the rhyolite of Gillies Hill altered and mineralized rocks at several places along the fault zone that marks the western margin of the Tushar Mountains; the zoned alunite and gold deposits at Sheep Rock, the gold deposit at the Sunday Mine, and an alunite deposit near Indian Creek were thus produced. Resetting of isotopic ages suggests that another center of hydrothermally altered rocks associated with a buried pluton about

  5. Bibliography of literature pertaining to Long Valley Caldera and associated volcanic fields

    Science.gov (United States)

    Ewert, John W.; Harpel, Christopher J.; Brooks, Suzanna K.; Marcaida, Mae

    2011-01-01

    define the beginning of the Brunhes Chron and helps constrain the Brunhes-Matuyama boundary. The Bishop ash, which was dispersed as far east as Nebraska, Kansas, and Texas, provides an important tephrostratigraphic marker throughout the Western United States. The obsidian domes of both the Mono and Inyo Craters, which were produced by rhyolitic eruptions in the past 40,000 years, have been well studied, including extensive scientific drilling through the domes. Exploratory drilling to 3-km depth on the resurgent dome and subsequent instrumentation of the Long Valley Exploratory Well (LVEW) have led to a number of important new insights. Scientific drilling also has been done within the Casa Diablo geothermal field, which, aside from drilling, has been commercially developed and is currently feeding 40 MW of power into the Southern California Edison grid. Studies in all the above-mentioned volcanic fields have contributed to the extensive scientific literature published on the Long Valley region. Although most of this scientific literature has been published since 1970, a significant amount of historical literature extends backward to the late 1800s. The purpose of this bibliography is to compile references pertaining to the Long Valley region from all time periods and all Earth science fields into a single listing, thus providing an easily accessible guide to the published literature for current and future researchers.

  6. Identification of maars and similar volcanic landforms in the West Eifel Volcanic Field through image processing of DTM data: efficiency of different methods depending on preservation state

    Science.gov (United States)

    Seib, Nadine; Kley, Jonas; Büchel, Georg

    2013-04-01

    The West Eifel Volcanic Field comprises 98 maars, tuff rings, and scoria rings of volcanoes younger than 700 ka. Digital Terrain Models (DTMs) allow to automatically measure morphologic parameters of volcanic edifices such as slope angles, diameters, elevations, floor, and slope surface areas. Based on their morphological characteristics, we subdivided the West Eifel volcanoes into five morphometric groups which reflect different stages of erosion. Group I, II, and IV comprise clear ring-shaped structures. The difference between these groups is that a tephra ring is well preserved in Group I, partially preserved in Group II and absent in Group IV. The original shapes of Group III maars have been lost more substantially than in Groups I, II, or IV, but they nevertheless retain a negative shape (a depression) and have characteristic channel systems, which can be used as search criteria. Maar-diatremes of Group V are eroded down to their feeder pipes and form hills. In order to locate potential volcanic depressions that are likely to be maar volcanoes, we defined common search criteria such as circular negative landforms or particular drainage system patterns for all groups except the least well-preserved Group V. These criteria were taken as the basis for further processing of the DTM data. The first processing step consisted of constructing a residual relief calculated as the difference between a filtered (smoothed) topographic surface and the original DTM data. This identifies local topographic features. We propose a method for regulating the degree of smoothing which is based on filtering of local maxima according to their distance from a surface constructed from local minima. The previously defined search criteria for Groups I to IV such as specific ranges of curvature, slope, circularity, density of the drainage network were then applied to the residual relief in order to extract maar shapes. Not all criteria work equally well for all morphological groups

  7. Catastrophic isotopic modification of rhyolitic magma at times of caldera subsidence, Yellowstone plateau volcanic field.

    Science.gov (United States)

    Hildreth, W.; Christiansen, R.L.; O'Neil, J.R.

    1984-01-01

    This Wyoming volcanic field has undergone repeated eruption of rhyolitic magma strongly depleted in 18O. Large calderas subsided 2.0, 1.3 and 0.6 m.y. ago on eruption of ash-flow sheets. More than 60 other rhyolite lavas and tuffs permit reconstruction of the long-term chemical and isotopic evolution of the silicic system. Narrow delta 18O ranges in the ash-flow sheets contrast with wide delta 18O variation in post-caldera lavas. The earliest post-collapse lavas are 3-6per mille lighter than the preceding ash-flow sheets. The 18O depletions were short-lived events that immediately followed caldera subsidence and sequences of post-caldera lavas record partial recovery toward pre-caldera delta 18O values. Contemporaneous extra-caldera rhyolites show no effects of the repeated depletions. Although some contamination by foundering roof rocks seems to be required, water was probably the predominant contaminant.-W.H.B.

  8. Crystallisation condition of the Quaternary basanites of volcanic centre Black Rock, monogenetic field Lunar Crater

    Science.gov (United States)

    Turova, Mariia; Plechov, Pavel; Scherbakov, Vasily; Larin, Nikolay

    2017-04-01

    The Lunar Crater volcanic field is located in a tension zone Basin and Range Province (USA). This tension is connected with dives oceanic plate under the continental plate [1]. Lunar Crater consists of flows basalt, basanite, trachybasalt has a different age [2]. In this work we investigate the youngest rock - basanite. The basanite is highly crystalline consisting of about megacrysts (3-10 cm) 30-60 wt% phenocrysts ( 800-1500 µm) and microphenocrysts (100-800 µm) and 40-60% microlites (Mathematical, Physical and Engineering Sciences. - 1981. - T. 300. - №. 1454. - C. 407-434. 2. Wood, X., and Keinle, Y., 1990, Volcanoes of North America: Cambridge,United Kingdom, Cambridge University Press, 354 p. 3. Nimis P. Clinopyroxene geobarometry of magmatic rocks. Part 2. Structural geobarometers for basic to acid, tholeiitic and mildly alkaline magmatic systems //Contributions to Mineralogy and Petrology. - 1999. - T. 135. - №. 1. - C. 62-74. 4. Ballhaus C., Berry R. F., Green D. H. High pressure experimental calibration of the olivine-orthopyroxene-spinel oxygen geobarometer: implications for the oxidation state of the upper mantle //Contributions to Mineralogy and Petrology. - 1991. - T. 107. - №. 1. - C. 27-40.

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

    Science.gov (United States)

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

    2017-08-09

    The Miocene Columbia River Basalt Group (CRBG) is the youngest and best preserved continental flood basalt province on Earth, linked in space and time with a compositionally diverse succession of volcanic rocks that partially record the apparent emergence and passage of the Yellowstone plume head through eastern Oregon during the late Cenozoic. This compositionally diverse suite of volcanic rocks are considered part of the La Grande-Owyhee eruptive axis (LOEA), an approximately 300-kilometer-long (185 mile), north-northwest-trending, middle Miocene to Pliocene volcanic belt located along the eastern margin of the Columbia River flood basalt province. Volcanic rocks erupted from and preserved within the LOEA form an important regional stratigraphic link between the (1) flood basalt-dominated Columbia Plateau on the north, (2) bimodal basalt-rhyolite vent complexes of the Owyhee Plateau on the south, (3) bimodal basalt-rhyolite and time-transgressive rhyolitic volcanic fields of the Snake River Plain-Yellowstone Plateau, and (4) the High Lava Plains of central Oregon.This field-trip guide describes a 4-day geologic excursion that will explore the stratigraphic and geochemical relationships among mafic rocks of the Columbia River Basalt Group and coeval and compositionally diverse volcanic rocks associated with the early “Yellowstone track” and High Lava Plains in eastern Oregon. Beginning in Portland, the Day 1 log traverses the Columbia River gorge eastward to Baker City, focusing on prominent outcrops that reveal a distal succession of laterally extensive, large-volume tholeiitic flood lavas of the Grande Ronde, Wanapum, and Saddle Mountains Basalt formations of the CRBG. These “great flows” are typical of the well-studied flood basalt-dominated Columbia Plateau, where interbedded silicic and calc-alkaline lavas are conspicuously absent. The latter part of Day 1 will highlight exposures of middle to late Miocene silicic ash-flow tuffs, rhyolite domes, and

  10. Continued Rapid Uplift at Laguna del Maule Volcanic Field (Chile) from 2007 through 2014

    Science.gov (United States)

    Le Mével, H.; Feigl, K. L.; Cordova, L.; DeMets, C.; Lundgren, P.

    2014-12-01

    The current rate of uplift at Laguna del Maule (LdM) volcanic field in Chile is among the highest ever observed geodetically for a volcano that is not actively erupting. Using data from interferometric synthetic aperture radar (InSAR) and the Global Positioning System (GPS) recorded at five continuously operating stations, we measure the deformation field with dense sampling in time (1/day) and space (1/hectare). These data track the temporal evolution of the current unrest episode from its inception (sometime between 2004 and 2007) to vertical velocities faster than 200 mm/yr that continue through (at least) July 2014. Building on our previous work, we evaluate the temporal evolution by analyzing data from InSAR (ALOS, TerraSAR-X, TanDEM-X) and GPS [http://dx.doi.org/ 10.1093/gji/ggt438]. In addition, we consider InSAR data from (ERS, ENVISAT, COSMO-Skymed, and UAVSAR), as well as constraints from magneto-telluric (MT), seismic, and gravity surveys. The goal is to test the hypothesis that a recent magma intrusion is feeding a large, existing magma reservoir. What will happen next? To address this question, we analyze the temporal evolution of deformation at other large silicic systems such as Yellowstone, Long Valley, and Three Sisters, during well-studied episodes of unrest. We consider several parameterizations, including piecewise linear, parabolic, and Gaussian functions of time. By choosing the best-fitting model, we expect to constrain the time scales of such episodes and elucidate the processes driving them.

  11. A Field Trip Guide to the Petrology of Quaternary Volcanism on the Yellowstone Plateau

    Science.gov (United States)

    Vazquez, Jorge A.; Stelten, Mark; Bindeman, Ilya N.; Cooper, Kari M

    2017-12-19

    The Yellowstone Plateau is one of the largest manifestations of silicic volcanism on Earth, and marks the youngest focus of magmatism associated with the Yellowstone Hot Spot. The earliest products of Yellowstone Hot Spot volcanism are from ~17 million years ago, but may be as old as ~32 Ma, and include contemporaneous eruption of voluminous mafic and silicic magmas, which are mostly located in the region of northwestern Nevada and southeastern Oregon. Since 17 Ma, the main locus of Yellowstone Hot Spot volcanism has migrated northeastward producing numerous silicic caldera complexes that generally remain active for ~2–4 million years, with the present-day focus being the Yellowstone Plateau. Northeastward migration of volcanism associated with the Yellowstone Hot Spot resulted in the formation of the Snake River Plain, a low relief physiographic feature extending ~750 kilometers from northern Nevada to eastern Idaho. Most of the silicic volcanic centers along the Snake River Plain have been inundated by younger basalt volcanism, but many of their ignimbrites and lava flows are exposed in the extended regions at the margins of the Snake River Plain. 

  12. A field trip guide to the petrology of Quaternary volcanism on the Yellowstone Plateau

    Science.gov (United States)

    Vazquez, Jorge A.; Stelten, Mark; Bindeman, Ilya N.; Cooper, Kari

    2017-12-19

    The Yellowstone Plateau is one of the largest manifestations of silicic volcanism on Earth, and marks the youngest focus of magmatism associated with the Yellowstone Hot Spot. The earliest products of Yellowstone Hot Spot volcanism are from ~17 million years ago, but may be as old as ~32 Ma, and include contemporaneous eruption of voluminous mafic and silicic magmas, which are mostly located in the region of northwestern Nevada and southeastern Oregon. Since 17 Ma, the main locus of Yellowstone Hot Spot volcanism has migrated northeastward producing numerous silicic caldera complexes that generally remain active for ~2–4 million years, with the present-day focus being the Yellowstone Plateau. Northeastward migration of volcanism associated with the Yellowstone Hot Spot resulted in the formation of the Snake River Plain, a low relief physiographic feature extending ~750 kilometers from northern Nevada to eastern Idaho. Most of the silicic volcanic centers along the Snake River Plain have been inundated by younger basalt volcanism, but many of their ignimbrites and lava flows are exposed in the extended regions at the margins of the Snake River Plain. 

  13. Relation of compositions of deep fluids in geothermal activity of Pleistocene-Holocene volcanic fields of Lesser Caucasus

    Science.gov (United States)

    Meliksetian, Khachatur; Lavrushin, Vassily; Shahinyan, Hrach; Aidarkozhina, Altin; Navasardyan, Gevorg; Ermakov, Alexander; Zakaryan, Shushan; Prasolov, Edward; Manucharyan, Davit; Gyulnazaryan, Shushan; Grigoryan, Edmond

    2017-04-01

    It is widely accepted, that geothermal activity in the conductive heat flow processes, such as volcanism and hydrothermal activity, is manifestation of the thermal mass transfer process in the Earth's crust, where geothermal and geochemical processes are closely connected. Therefore, geochemistry and isotope compositions of thermal mineral waters within and on periphery of volcanic clusters may represent key indicators for better understanding of geothermal activity in geodynamically active zones. Geochemical features of heat and mass transport in hydrothermal systems related to active volcanic and fault systems in continental collision related orogenic elevated plateaus such as Anatolian-Armenian-Iranian highlands are still poorly understood. In this contribution we attempt to fill these gaps in our knowledge of relations of geochemical and geothermal processes in collision zones. We present new data on chemical compositions, trace element geochemistry of thermal waters of Lesser Caucasus, (Armenia) as well as isotope analysis of free gases such as {}3He/{}4He, {}40Ar/{}36Ar, δ{}13?(CO{}2), nitrogen δ{}15N(N{}2) and oxygen and hydrogen isotopes in water phases (δD, δ{}18O). To reveal some specific features of formation of fluid systems related to thermal activity in the areas of collision related active volcanism and active geodynamics a complex geochemical (SiO{}2, K-Na, Na-Li, Li-Mg) and isotope geothermometers (δ{}18O(CaCO{}3) - δ{}18O(H{}2O)) were applied. The distribution of δ{}13?(??{}2) values in free gases of mineral waters of Armenia demonstrates that gases related to Quaternary volcanic fields are characterized by relatively light δ{}13?(CO{}2) values close to mantle derived gases, while on periphery of volcanic systems relatively heavy values of δ{}13?(CO{}2) indicate strong influence of metamorphic and sedimentary derived carbon dioxide. Distribution of nitrogen isotopes δ{}15N(N{}2) demonstrate an inverse correlation with δ{}13?(CO{}2

  14. A geologic and anthropogenic journey from the Precambrian to the new energy economy through the San Juan volcanic field

    Science.gov (United States)

    Yager, Douglas B.; Burchell,; Johnson, Raymond H.

    2010-01-01

    The San Juan volcanic field comprises 25,000 km2 of intermediate composition mid-Tertiary volcanic rocks and dacitic to rhyolitic calderas including the San Juan–Uncompahgre and La Garita caldera-forming super-volcanoes. The region is famous for the geological, ecological, hydrological, archeological, and climatological diversity. These characteristics supported ancestral Puebloan populations. The area is also important for its mineral wealth that once fueled local economic vitality. Today, mitigating and/or investigating the impacts of mining and establishing the region as a climate base station are the focuses of ongoing research. Studies include advanced water treatment, the acid neutralizing capacity (ANC) of propylitic bedrock for use in mine-lands cleanup, and the use of soil amendments including biochar from beetle-kill pines. Biochar aids soil productivity and revegetation by incorporation into soils to improve moisture retention, reduce erosion, and support the natural terrestrial carbon sequestration (NTS) potential of volcanic soils to help offset atmospheric CO2 emissions. This field trip will examine the volcano-tectonic and cultural history of the San Juan volcanic field as well as its geologic structures, economic mineral deposits and impacts, recent mitigation measures, and associated climate research. Field trip stops will include a visit to (1) the Summitville Superfund site to explore quartz alunite-Au mineralization, and associated alteration and new water-quality mitigation strategies; (2) the historic Creede epithermal-polymetallic–vein district with remarkably preserved resurgent calderas, keystone-graben, and moat sediments; (3) the historic mining town of Silverton located in the nested San Juan–Silverton caldera complex that exhibits base-metal Au-Ag mineralization; and (4) the site of ANC and NTS studies. En route back to Denver, we will traverse Grand Mesa, a high NTS area with Neogene basalt-derived soils and will enjoy a soak

  15. Geothermal Potential of Marine Corps Air Station, Yuma, Arizona, and the Western Portion of Luke-Williams Gunnery Range

    Science.gov (United States)

    1988-01-01

    Domes in the Northern Part of the Gulf of California," in Symposia on the Cerro Prieto Geothermal Field, Baja California, Mexico, Comision Federal de...Laboratory, August 1979. LA-7953-MS. 22 pp. 10. J. de Boer. "Paleomagnetism of the Quaternary Cerro Prieto , Crater Elegante, and Salton Buttes Volcanic...NWC TP 6827 S Geothermal Potential of Marine Corps Air Station, Yuma, Arizona, and the Western Portion of Luke-Williams Gunnery Range by Steven C

  16. Petrochemistry of late miocene peraluminous silicic volcanic rocks from the Morococala field, Bolivia

    Science.gov (United States)

    Morgan, VI G.B.; London, D.; Luedke, R.G.

    1998-01-01

    Late Miocene peraluminous volcanic rocks of the Morococala field, Bolivia, define a layered stratigraphy of basal andalusite-, biotite-(?? Muscovite)-bearing rhyolite tuffs (AR), overlain by cordierite-, biotite-bearing rhyolite tuffs (CR), and capped by biotite-beanng quartz latite tuffs, lavas, and late domal flows (QL). Mineral and whole-rock compositions become more evolved from top to bottom, with differentiation reflected by decreasing Ca, Ba, Mg, Fe, and rare earth elements (REE) versus increasing F, Na/K, and aluminosity from QL to AR. Mineral, whole-rock, and glass inclusion compositions are consistent with derivation of all three rock types from a single stratified magma reservoir, but age and spatial relations between the three units make this unlikely. Genesis of the QL involved biotite-dehydration melting of an aluminous source at T > 750??C and P ??? 4-6 kbar. If not co-magmatic with QL, the other units were generated primarily by muscovite-dehydration melting at T = 730-750??C and P ??? 3??5-4??5 kbar for CR, and T ??? 750??C for AR with pre-emptive residence at low pressure (1??5-3??0 kbar). Low hematite contents (XHem ??? 0??06) of ilmenite grains in AR, CR, and early grains (as inclusions in plagioclase and sanidine cores) in QL indicate reduced conditions imposed by a graphite-bearing source. Compositional variability among texturally later oxides (ilmenite with XHem = 0??06-0??50, primary magnetite), however, apparently records progressive increases in pre-eruptive f(O2) in QL. Plagioclase-melt equilibria and electron microprobe analysis difference for quartz-hosted glass inclusions suggest pre-emptive melt H2O contents ??? 5-7 wt % for the AR, ???4-6 wt % for the CR, and ???3-5 wt % for the QL.

  17. Hydrothermal alteration in oceanic ridge volcanics: A detailed study at the Galapagos Fossil Hydrothermal Field

    Science.gov (United States)

    Ridley, W.I.; Perfit, M.R.; Josnasson, I.R.; Smith, M.F.

    1994-01-01

    The Galapagos Fossil Hydrothermal Field is composed of altered oceanic crust and extinct hydrothermal vents within the eastern Galapagos Rift between 85??49???W and 85??55???W. The discharge zone of the hydrothermal system is revealed along scarps, thus providing an opportunity to examine the uppermost mineralized, and highly altered interior parts of the crust. Altered rocks collected in situ by the submersible ALVIN show complex concentric alteration zones. Microsamples of individual zones have been analysed for major/minor, trace elements, and strontium isotopes in order to describe the complex compositional details of the hydrothermal alteration. Interlayered chlorite-smectite and chlorite with disequilibrium compositions dominate the secondary mineralogy as replacement phases of primary glass and acicular pyroxene. Phenocrysts and matrix grains of plagioclase are unaffected during alteration. Using a modification of the Gresens' equation we demonstrate that the trivalent rare earth elements (REEs) are relatively immobile, and calculate degrees of enrichment and depletion in other elements. Strontium isotopic ratios increase as Sr concentrations decrease from least-altered cores to most-altered rims and cross-cutting veins in individual samples, and can be modeled by open system behaviour under low fluid-rock ratio (< 10) conditions following a period of lower-temperature weathering of volcanics within the rift zone. The complex patterns of element enrichment and depletion and strontium isotope variations indicate mixing between pristine seawater and ascending hot fluids to produce a compositional spectrum of fluids. The precipitation of base-metal sulfides beneath the seafloor is probably a result of fluid mixing and cooling. If, as suggested here, the discharge zone alteration occurred under relatively low fluid-rock ratios, then this shallow region must play an important role in determining the exit composition of vent fluids in marine hydrothermal systems

  18. The ~ 2000 yr BP Jumento volcano, one of the youngest edifices of the Chichinautzin Volcanic Field, Central Mexico

    Science.gov (United States)

    Arce, J. L.; Muñoz-Salinas, E.; Castillo, M.; Salinas, I.

    2015-12-01

    The Chichinautzin Volcanic Field is situated at the southern limit of the Basin of Mexico and the Metropolitan area of Mexico City, the third most populated city around the world. The Chichinautzin Volcanic field holds more than 220 monogenetic volcanoes. Xitle is the youngest of these with an estimated age of 1.6 ky BP. Xitle's eruptive activity took place during the Mesoamerican Mexican Pre-classic period and is related to the destruction of Cuicuilco Archaeological Site, the oldest civilization known in Central Mexico. However, there are still several regional cones that have not been dated. Based on 14C ages, stratigraphic and geomorphologic criteria, we conclude that the Jumento volcano, located to the west of Xitle, is one of the youngest cones of the Chichinautzin Volcanic Field. The Jumento volcano has a basaltic andesite composition, and its eruptive activity was initially hydromagmatic, followed by Strombolian and finally effusive events occurred recorded through: (1) a sequence of hydromagmatic pyroclastic surges and ashfall layers emplaced at a radius of > 5 km from the crater with charcoal fragments at its base; this activity built the Jumento's cone with slopes of 32°; and (2) lava flows that breached the southern part of the cone and flowed for up to 2.5 km from the vent. The resulting 14C ages for this volcano yielded a maximum age of 2 ky BP. Morphometric analysis indicates that the state of degradation of Jumento cone is similar to the Xitle, suggesting that the Jumento could be in the state of degradation of a volcanic structure of similar age or younger adding credence to the probable radiocarbon age of 2 ky BP for the Jumento edifice.

  19. Evolution of unrest at Laguna del Maule volcanic field (Chile) from InSAR and GPS measurements, 2003 to 2014

    Science.gov (United States)

    Le Mével, Hélène; Feigl, Kurt L.; Córdova, Loreto; DeMets, Charles; Lundgren, Paul

    2015-08-01

    The Laguna del Maule (LdM) volcanic field in the southern volcanic zone of the Chilean Andes exhibits a large volume of rhyolitic material erupted during postglacial times (20-2 ka). Since 2007, LdM has experienced an unrest episode characterized by high rates of deformation. Analysis of new GPS and Interferometric Synthetic Aperture Radar (InSAR) data reveals uplift rates greater than 190 mm/yr between January 2013 and November 2014. The geodetic data are modeled as an inflating sill at depth. The results are used to calculate the temporal evolution of the vertical displacement. The best time function for modeling the InSAR data set is a double exponential model with rates increasing from 2007 through 2010 and decreasing slowly since 2010. We hypothesize that magma intruding into an existing silicic magma reservoir is driving the surface deformation. Modeling historical uplift at Yellowstone, Long Valley, and Three Sisters volcanic fields suggests a common temporal evolution of vertical displacement rates.

  20. Geochemical constraints on the relationship between the Miocene-Pliocene volcanism and tectonics in the Palaoco and Fortunoso volcanic fields, Mendoza Region, Argentina

    DEFF Research Database (Denmark)

    Dyhr, Charlotte Thorup; Holm, Paul Martin; Llambias, Eduardo J.

    2013-01-01

    New 40Ar/39Ar analyses constrain the formation of the volcanic succession of Sierra de Palaoco in the present back-arc of the Andean Southern Volcanic Zone (SVZ), near 36°S, to the Late Miocene and assigns them to the Huincán II Formation. The composition of major and trace elements, Sr, Nd and P...

  1. A unique volcanic field in Tharsis, Mars: Pyroclastic cones as evidence for explosive eruptions

    Czech Academy of Sciences Publication Activity Database

    Brož, Petr; Hauber, E.

    2012-01-01

    Roč. 218, č. 1 (2012), s. 88-99 ISSN 0019-1035 R&D Projects: GA MŠk ME09011 Institutional research plan: CEZ:AV0Z30120515 Keywords : Mars * volcanism * Mars surface Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 3.161, year: 2012

  2. Geochemical/hydrochemical evaluation of the geothermal potential of the Lamongan volcanic field (Eastern Java, Indonesia)

    NARCIS (Netherlands)

    Deon, F.; Förster, H.J.; Brehme, M.; Wiegand, B.; Scheytt, T.; Moeck, I.; Jaya, M.S.; Putriatni, D.J.

    2015-01-01

    Magmatic settings involving active volcanism are potential locations for economic geothermal systems due to the occurrence of high temperature and steam pressures. Indonesia, located along active plate margins, hosts more than 100 volcanoes and, therefore, belongs to the regions with the greatest

  3. Influence of hydrothermal venting on water column properties in the crater of the Kolumbo submarine volcano, Santorini volcanic field (Greece)

    Science.gov (United States)

    Christopoulou, Maria E.; Mertzimekis, Theo J.; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Carey, Steven; Mandalakis, Manolis

    2016-02-01

    The Kolumbo submarine volcano, located 7 km northeast of the island of Santorini, is part of Santorini's volcanic complex in the south Aegean Sea, Greece. Kolumbo's last eruption was in 1650 AD. However, a unique and active hydrothermal vent field has been revealed in the northern part of its crater floor during an oceanographic survey by remotely operated vehicles (ROVs) in 2006. In the present study, conductivity-temperature-depth (CTD) data collected by ROV Hercules during three oceanographic surveys onboard E/V Nautilus in 2010 and 2011 have served to investigate the distribution of physicochemical properties in the water column, as well as their behavior directly over the hydrothermal field. Additional CTD measurements were carried out in volcanic cone 3 (VC3) along the same volcanic chain but located 3 km northeast of Kolumbo where no hydrothermal activity has been detected to date. CTD profiles exhibit pronounced anomalies directly above the active vents on Kolumbo's crater floor. In contrast, VC3 data revealed no such anomalies, essentially resembling open-sea (background) conditions. Steep increases of temperature (e.g., from 16 to 19 °C) and conductivity near the maximum depth (504 m) inside Kolumbo's cone show marked spatiotemporal correlation. Vertical distributions of CTD signatures suggest a strong connection to Kolumbo's morphology, with four distinct zones identified (open sea, turbid flow, invariable state, hydrothermal vent field). Additionally, overlaying the near-seafloor temperature measurements on an X-Y coordinate grid generates a detailed 2D distribution of the hydrothermal vent field and clarifies the influence of fluid discharges in its formation.

  4. Building on Decades of Research on the McMurdo Volcanic Group, Antarctica: A Geologic Field Guide to Observation Hill

    Science.gov (United States)

    Pound, K. S.; Panter, K. S.

    2008-12-01

    Based on more than four decades of research on the rocks of the Erebus Volcanic Province of the McMurdo Volcanic Group, a geologic field guide to the Observation Hill walking tracks near McMurdo Station, Antarctica has been developed. The geologic field guide was an outcome of questions generated by: (1) Teachers participating in the Andrill Research Immersion for Science Educators (ARISE) program; (2) McMurdo Station support staff, as well as (3) Geoscientists with specialties outside volcanology and petrology. Whilst these individuals are acutely aware of the more than a century of references to Observation Hill in exploration literature, there was little in the way of easily-accessible information about the geologic history of Hut Point and Observation Hill, as well as other nearby volcanoes (e.g. Mt. Erebus, White and Black Islands) and larger scale geologic features (e.g. Transantarctic Mountains) that can be seen from the vantage point of Observation Hill. Questions also focused on smaller scale features of the landscape (e.g. patterned ground) and textures and minerals observed in volcanic rocks exposed on the trails. In order to encompass the wide-ranging background of the audience and facilitate access, the field guide will be available in three formats: (1) A downloadable MP3 file, which includes the general information and stop-by- stop information; (2) A double-sided paper brochure that provides a relatively simple, easier-to-digest guide to views and geologic features; (3) A Google Earth Layer that includes access to the MP3 files and the paper brochure, as well as additional geologic information. Links to the field guide can be found at http://www.andrill.org/education.

  5. Melding Research on the Navajo Volcanic Field into Undergraduate Curriculum to Promote Scientific Literacy

    Science.gov (United States)

    Gonzales, D. A.

    2011-12-01

    This presentation highlights the curricular design and preliminary outcomes of undergraduate research in the Department of Geosciences at Fort Lewis College (FLC), supported by an NSF-RUI project on the Navajo volcanic field (NVF). A prime impact of this project was to support the education and career development of undergraduate students by further developing basic knowledge and skills in the context of authentic inquiry on petrologic-based research topics. Integrating research into the curriculum promoted scientific habits of mind by engaging students as "active agents" in discovery, and the creative development and testing of ideas. It also gave students a sense of ownership in the scientific process and knowledge construction. The initial phase of this project was conducted in Igneous Petrology at FLC in 2010. Eleven students were enrolled in this course which allowed them to work as a team in collaboration with the PI, and engage in all aspects of research to further develop and hone their skills in scientific inquiry. This course involved a small component of traditional lecture in which selected topics were discussed to provide students with a foundation to understand magmatic processes. This was complemented by a comprehensive review of the literature in which students read and discussed a spectrum of articles on Tertiary magmatism in the western United States and the NVF. Invited lectures by leading-scientists in geology provided opportunities for discussions and interaction with professional geologists. All of the students in the class engaged in the active collection of petrologic data in the field and laboratory sessions, and were introduced to the use of state-of-the art analytical tools as part of their experiences. Four students were recruited from the course to design, develop, and conduct long-term research projects on selected petrologic topics in the NVF. This research allowed these students to engage in the "messy" process of testing existing

  6. Preliminary paragenetic interpretation of the Quaternary topaz rhyolite lava domes of the Blackfoot volcanic field, southeastern Idaho

    Science.gov (United States)

    Lochridge, W. K., Jr.; McCurry, M. O.; Goldsby, R.

    2015-12-01

    The Quaternary topaz rhyolite lava domes of the bimodal, basalt-dominated Blackfoot volcanic field (BVF), SE Idaho occur in three clusters. We refer to these as the China Hat lava dome field (southernmost; ~ 57 ka), and the 1.4 to 1.5 Ma Sheep Island and White Mountain (northernmost) lava dome fields. The rhyolites and surrounding, more voluminous basalt lavas closely resemble coeval Quaternary rocks erupted to the north along the Eastern Snake River Plain segment of the Yellowstone-Snake River Plain volcanic track. However rhyolites in BVF are distinguished by having more evolved Sr- and Nd-isotopic ratios, as well as having phenocryst assemblages that includes hydrous phases (biotite and hornblende), thorite, and vapor-phase topaz. This study seeks to improve our understanding of the unique conditions of magma evolution that led to these differences. We focus on textural features of major and accessory phenocrysts as a basis for inferring paragenesis for rhyolites from the China Hat lava dome field. Preliminary work indicates that there are three sequentially formed populations of textures among magmatic phases: 1. population of anhedral quartz and plagioclase; 2. population of euhedral grains that includes quartz, sandine, plagioclase, biotite, hornblende, Fe-Ti oxides, zircon and apatite; 3. boxy cellular (skeletal?) sanidine and quartz. We speculate that the first population are resorbed antecrysts, the second formed prior to eruption as autocrysts (at or near equilibrium?), and the third formed soon before or during eruption.

  7. Development of a geothermal resource in a fractured volcanic formation: Case study of the Sumikawa Geothermal Field, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Garg, S.K.; Pritchett, J.W.; Stevens, J.L.; Luu, L. [Maxwell Federal Div., Inc., San Diego, CA (United States); Combs, J. [Geo-Hills Associates, Los Altos, CA (United States)

    1996-11-01

    The principal purpose of this case study of the Sumikawa Geothermal Field is to document and to evaluate the use of drilling logs, surface and downhole geophysical measurements, chemical analyses, and pressure transient data for the assessment of a high temperature volcanic geothermal field. The work accomplished during Year 1 of this ongoing program is described in the present report. A brief overview of the Sumikawa Geothermal Field is given. The drilling information and downhole pressure, temperature, and spinner surveys are used to determine feedzone locations, pressures and temperatures. Available injection and production data from both slim holes and large-diameter wells are analyzed to evaluate injectivity/productivity indices and to investigate the variation of discharge rate with borehole diameter. Finally, plans for future work are outlined.

  8. Petrology and Geochemistry of Hydrothermally Altered Volcanic Rocks in the Iheya North Hydrothermal Field, Middle Okinawa Trough

    Science.gov (United States)

    Yamasaki, T.

    2015-12-01

    The Iheya North hydrothermal field is located in the middle Okinawa Trough, a young and actively spreading back-arc basin extending behind the Ryukyu arc-trench system in the southeastern margin of the East China Sea. In this hydrothermal field, two scientific drilling expeditions (IODP Exp 331 and SIP CK14-04) were conducted using a deep-sea drilling vessel "Chikyu," and samples from a total of 27 holes were taken. Through these expeditions, Kuroko-type volcanogenic massive sulfide deposits (VMS), hydrothermally altered volcanic rocks, and pumiceous and pelagic sediments were recovered. The recovered core provided important information about the relationship between hydrothermal activity, alteration, and ore mineralization. Whole-rock major element composition and trace element (TE) patterns of pumices were very similar to those of rhyolites in the middle Okinawa Trough (RMO). However, pumices were relatively enriched in chalcophile elements Sr and Nb, which suggest incipient mineralization. Volcanic rock generally demonstrated strong silicification and was greenish pale gray in color. Regardless of severe alteration, some rock displayed major element composition broadly similar to the RMO. Alteration was evidenced by an increase in the content of SiO2 and MgO, and decrease in Al2O3, Na2O, and K2O content. The most striking geochemical feature of altered volcanic rock was the discordance between texture and the degree of modification of TEs. Some samples showed decussate texture occupied by petal-like quartz with severe silicification, but no prominent disturbance of concentration and patterns of TEs were observed. In contrast, samples with well-preserved igneous porphyritic texture showed very low TE content and modification of TE patterns. These results suggest that the modification of texture and composition of TEs, as well as silicification, do not occur by a uniform process, but several processes. This may reflect the differences in temperature and the

  9. Polybrominated diphenyl ether metabolism in field collected fish from the Gila River, Arizona, USA-Levels, possible sources, and patterns

    Science.gov (United States)

    Echols, Kathy R.; Peterman, Paul H.; Hinck, Jo Ellen; Orazio, Carl E.

    2013-01-01

    Polybrominated diphenyl ethers (PBDEs) were determined in fish collected from the Gila River, Arizona, a tributary of the Colorado River in the lower part of the Colorado River Basin. Fish samples were collected at sites on the Gila River downstream from Hayden, Phoenix, and Arlington, Arizona in late summer 2003. The Gila River is ephemeral upstream of the Phoenix urban area due to dams and irrigation projects and has limited perennial flow downstream of Phoenix due to wastewater and irrigation return flows. Fifty PBDE congeners were analyzed by high resolution gas chromatography/high resolution mass spectrometry using labeled surrogate standards in composite samples of male and female common carp (Cyrpinus carpio), largemouth bass (Micropterus salmoides) and channel catfish (Ictalurus punctatus). The predominant PBDE congeners detected and quantified were 47, 100, 153, 49, 28, and 17. Concentrations of total PBDEs in these fish ranged from 1.4 to 12700 ng g-1 wet weight, which are some of the highest concentrations reported in fish from the United States. Differences in metabolism of several PBDE congeners by carp is clear at the Phoenix site; congeners with at least one ring of 2,4,5-substitution are preferentially metabolized as are congeners with 2,3,4-substitution.

  10. Determining volcanic SO2 plume heights in satellite observations using meteorological wind fields

    Science.gov (United States)

    Keicher, Viktoria; Hörmann, Christoph; Sihler, Holger; Platt, Ulrich; Wagner, Thomas

    2016-04-01

    Satellite observations nowadays provide the global monitoring of volcanic plumes via sulphur dioxide (SO2) that is injected into the Earth's atmosphere. In turn, SO2 may lead to the formation of sulphate aerosols that can influence climate via direct and indirect radiative effects. The retrieval of SO2 requires an accurate plume height estimate in order to constrain total amounts for such events. One of the main difficulties for the retrieval is the typically unknown atmospheric profile resulting from unknown initial conditions (individual explosions over an extended time period leading to different gas layer altitudes and influencing the atmospheric transport pattern). In recent years, satellite observations helped to improve global SO2 estimates, but still large uncertainties exist. Passive satellite remote sensing using measurements in the UV/vis spectral range for example offers the opportunity to observe the location of a plume in two dimensions, but information about the corresponding height is sparse. Furthermore, information about these plume profiles is not only interesting in itself (e.g. to assess the radiative effect of volcanic plumes). It is also important for the quantitative interpretation of satellite observations. Here, we present first results for a newly developed approach using the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) in combination with data for different volcanic SO2 plumes as observed by the second generation Global Ozone Monitoring Instrument (GOME-2). The main plume information that can be retrieved by the satellite (i.e. plume location and observation time) are used as initial input parameters in order to estimate the plume's profile at the time of the measurements. For selected case studies we use these trajectories to further estimate values the eruption time and height. The correspondingly modelled values can also be used to verify the results when they are compared to direct local observations and

  11. Flagstaff, Arizona seen in Earth Resources Experiments package

    Science.gov (United States)

    1974-01-01

    A spectacular winter view of the Flagstaff, Arizona area is seen in this Skylab 4 Earth Resources Experiments package S190-B (five-inch earth terrain camera) infrared photograph taken from the Skylab space station in Earth orbit. Included in the scene are the San Francisco Mountains, Oak Creek Canyon, Painted Desert and Meteor Crater. The infrared picture depicts in red living vegetation, in white the snow, and in bright blue the water. Major features identified in this photograph are Humphrey's peak, top center, Flagstaff at foot of the peak, Sunset Crater volcanic field with numerous vents and craters right of Flagstaff and Meteor Crater (right center). Within the mountainous areas several clear areas generally rectangular are visible and represent the areas where lumbering has removed the forest. The thin white line extending from left corner to Sunset Crater fields is the power transmission line cleared area. Roads are subdued and are not easily visible.

  12. Crustal deformation and magmatic processes at Laguna del Maule volcanic field (Chile): Geodetic measurements and numerical models

    Science.gov (United States)

    Le Mével, Hélène

    The Laguna del Maule (LdM) volcanic field in Chile is an exceptional example of postglacial rhyolitic volcanism in the Southern Volcanic Zone of the Andes. Since 2007, LdM has experienced an unrest episode characterized by high rates of deformation measured by interferometric analysis of synthetic aperture radar (SAR) images acquired between 2007 and 2016, and data from the Global Positioning System (GPS) recorded since 2012 at five stations. The inflating region includes most of the 16--km-by--14--km ring of rhyolitic domes and coulees. The fastest-moving GPS station (MAU2) has a velocity vector of [[special character omited]72 +/- 4, 19 +/- 1, 194 +/- 3] mm/yr between 2012 and 2016 for the eastward, northward, and upward components, respectively. First, we model the InSAR observations assuming a rectangular dislocation in a half space with uniform elastic properties. The best time function for modeling the InSAR data set is a double exponential model with rates increasing from 2007 through 2010 and decreasing slowly since 2011. Modeling of historical uplift at Yellowstone, Long Valley, and Three Sisters volcanic fields suggests a common temporal evolution of vertical displacement rates. We hypothesize that magma intruding into an existing silicic magma reservoir is driving the surface deformation and present a new dynamic model to describe this process. A Newtonian fluid characterized by its viscosity, density, and pressure flows through a vertical conduit, intruding into a reservoir embedded in an elastic domain and leading to time-dependent surface deformation. Using a grid-search optimization, we minimize the misfit to the InSAR displacement data by varying the three parameters governing the analytical solution: the characteristic timescale tauP for magma propagation, the injection pressure, and the inflection time when the acceleration switches from positive to negative. For a spheroid with semi-major axis a = 6200 m, semi-minor axis c = 100 m, located at a

  13. Petrologic evolution of divergent peralkaline magmas from the Silent Canyon caldera complex, southwestern Nevada volcanic field

    Science.gov (United States)

    Sawyer, D.A.; Sargent, K.A.

    1989-01-01

    The Silent Canyon volcanic center consists of a buried Miocene peralkaline caldera complex and outlying peralkaline lava domes. Two widespread ash flow sheets, the Tub Spring and overlying Grouse Canyon members of the Miocene Belted Range Tuff, were erupted from the caldera complex and have volumes of 60-100 km3 and 200 km3, respectively. Eruption of the ash flows was preceded by widespread extrusion of precaldera comendite domes and was followed by extrusion of postcollapse peralkaline lavas and tuffs within and outside the caldera complex. Lava flows and tuffs were also deposited between the two major ash flow sheets. Rocks of the Silent Canyon center vary significantly in silica content and peralkalinity. Weakly peralkaline silicic comendites (PI 1.0-1.1) are the most abundant precaldera lavas. Postcollapse lavas range from trachyte to silicic comendite; some have anomalous light rare earth element (LREE) enrichments. Silent Canyon rocks follow a common petrologic evolution from trachyte to low-silica comendite; above 73% SiO2, compositions of the moderately peralkaline comendites diverge from those of the weakly peralkaline silicic comendites. The development of divergent peralkaline magmas, toward both pantelleritic and weakly peralkaline compositions, is unusual in a single volcanic center. -from Authors

  14. The geomagnetic field intensity in New Zealand: palaeointensities from Holocene lava flows of the Tongariro Volcanic Centre

    Science.gov (United States)

    Greve, Annika; Hill, Mimi J.; Turner, Gillian M.; Nilsson, Andreas

    2017-11-01

    Very few absolute palaeointensity data exist from Holocene-aged rocks in New Zealand. Here we present a new suite of high-quality palaeointensities, supported by detailed rock magnetic investigations. Samples from 23 sites representing 10 distinct eruptive units of the Tongariro Volcanic Centre, Taupo Volcanic Zone, New Zealand, were studied. Both traditional double heating and microwave palaeointensity methods were employed. The reliability of the palaeointensity data varies with rock magnetic properties of the samples, corresponding, in particular, to their positions within the lava flows. The highest success rates are from samples obtained from near the flow tops where a significant proportion of the remanence unblocked at intermediate temperatures (200-350 °C). By contrast, samples from flow centres, particularly the parts showing platey fracturing, have the lowest success rates. Reliable, high-quality palaeointensity results ranging from 32.4 ± 5.1 μT to 72.1 ± 4.7 μT were obtained from six flows with ages between c. 12 800 yr BP and the present. These correspond to virtual dipole moments that increase from 52 ± 10 ZAm2 in the early Holocene and peak at 112 ± 14 ZAm2 about 300 yr ago. The data agree well with calibrated relative palaeointensities from New Zealand lake sediments. The volcanic and sedimentary data together yield a Holocene virtual axial dipole moment curve that fits the global average variation well in the early Holocene, but which differs significantly in recent millennia. This difference is associated with recent migration of the southern high latitude core-mantle boundary flux lobe towards New Zealand, as is seen in global field models.

  15. Constraints on the origin and evolution of magmas in the Payún Matrú Volcanic Field, Quaternary Andean back-arc of western Argentina

    DEFF Research Database (Denmark)

    Hernadno, I R; Aragón, E; Frei, Robert

    2014-01-01

    caldera 8 km wide) and Payún Liso (a smaller stratovolcano). The volcanic field includes about 200 scoria cones and alkali basaltic and trachybasaltic lava flows, forming two basaltic fields around Payún Matrú. New 40Ar–39Ar ages extend the activity of Payún Matrú up to 700 ka. The major and trace element...

  16. 40Ar/39Ar geochronology and geochemical reconnaissance of the Eocene Lowland Creek volcanic field, west-central Montana

    Science.gov (United States)

    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 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.

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

    Science.gov (United States)

    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

  18. Evaluation of the evolving stress field of the Yellowstone volcanic plateau, 1988 to 2010, from earthquake first-motion inversions

    Science.gov (United States)

    Russo, E.; Waite, G. P.; Tibaldi, A.

    2017-03-01

    Although the last rhyolite eruption occurred around 70 ka ago, the silicic Yellowstone volcanic field is still considered active due to high hydrothermal and seismic activity and possible recent magma intrusions. Geodetic measurements document complex deformation patterns in crustal strain and seismic activity likewise reveal spatial and temporal variations in the stress field. We use earthquake data recorded between 1988 and 2010 to investigate these variations and their possible causes in more detail. Earthquake relocations and a set of 369 well-constrained, double-couple, focal mechanism solutions were computed. Events were grouped according to location and time to investigate trends in faulting. The majority of the events have normal-faulting solutions, subordinate strike-slip kinematics, and very rarely, reverse motions. The dominant direction of extension throughout the 0.64 Ma Yellowstone caldera is nearly ENE, consistent with the perpendicular direction of alignments of volcanic vents within the caldera, but our study also reveals spatial and temporal variations. Stress-field solutions for different areas and time periods were calculated from earthquake focal mechanism inversion. A well-resolved rotation of σ3 was found, from NNE-SSW near the Hebgen Lake fault zone, to ENE-WSW near Norris Junction. In particular, the σ3 direction changed throughout the years around Norris Geyser Basin, from being ENE-WSW, as calculated in the study by Waite and Smith (2004), to NNE-SSW, while the other σ3 directions are mostly unchanged over time. The presence of ;chocolate tablet; structures, with two sets of nearly perpendicular normal faults, was identified in many stages of the deformation history both in the Norris Geyser Basin area and inside the caldera.

  19. Improved techniques in data analysis and interpretation of potential fields: examples of application in volcanic and seismically active areas

    Directory of Open Access Journals (Sweden)

    G. Florio

    2002-06-01

    Full Text Available Geopotential data may be interpreted by many different techniques, depending on the nature of the mathematical equations correlating specific unknown ground parameters to the measured data set. The investigation based on the study of the gravity and magnetic anomaly fields represents one of the most important geophysical approaches in the earth sciences. It has now evolved aimed both at improving of known methods and testing other new and reliable techniques. This paper outlines a general framework for several applications of recent techniques in the study of the potential methods for the earth sciences. Most of them are here described and significant case histories are shown to illustrate their reliability on active seismic and volcanic areas.

  20. Thermal, radioactive and magnetic properties of the lavas of the Mt Melbourne Volcanic Field (Victoria Land, Antarctica

    Directory of Open Access Journals (Sweden)

    Egidio Armadillo

    2009-06-01

    Full Text Available We present the results of measurements of physical properties carried out on mafic lavas from the Mt Melbourne
    Volcanic Field, useful for interpretation of geophysical surveys designed to shed light on the structure of the
    crust. The thermal conductivity is comparable to that of glass and shows a clear negative dependence on porosity.
    The volume heat capacity and the thermal diffusivity are less variable. The concentration of the thermally
    important natural radioactive isotopes was determined by gamma-ray spectrometry. Lavas denoted a rather low
    heat-production rate, and the largest concentration of heat-producing elements (potassium, uranium, thorium
    was found in the trachyte samples. The magnetic susceptibility is more variable than the other physical properties
    and, among the several iron-titanium oxides, it appears primarily controlled by the ulvöspinel-magnetite solid
    solution series.

  1. Stability Evaluation of Volcanic Slope Subjected to Rainfall and Freeze-Thaw Action Based on Field Monitoring

    Directory of Open Access Journals (Sweden)

    Shima Kawamura

    2011-01-01

    Full Text Available Rainfall-induced failures of natural and artificial slopes such as cut slopes, which are subjected to freezing and thawing, have been frequently reported in Hokkaido, Japan. In particular, many failures occur intensively from spring to summer seasons. Despite numerous field studies, explanation of their mechanical behavior based on in situ data has not yet been completely achieved due to the difficulty in grasping failure conditions. This study aims at clarifying the aspects of in-situ volcanic slopes subjected to rainfall and freeze-thaw action. The changes in soil moisture, pore pressure, deformations, and temperatures in the slope were investigated using soil moisture meters, tensiometers, thermocouple sensors, clinometers, settlement gauges, an anemovane, a snow gauge, and a rainfall gauge. The data generated from these measures indicated deformation in the slope examined mainly proceeded during the drainage process according to changes in soil moisture. Based on this data, a prediction method for failures is discussed in detail.

  2. Hydrothermal uranium deposits containing molybdenum and fluorite in the Marysvale volcanic field, west-central Utah

    Science.gov (United States)

    Cunningham, C.G.; Rasmussen, J.D.; Steven, T.A.; Rye, R.O.; Rowley, P.D.; Romberger, S.B.; Selverstone, J.

    1998-01-01

    Uranium deposits containing molybdenum and fluorite occur in the Central Mining Area, near Marysvale, Utah, and formed in an epithermal vein system that is part of a volcanic/hypabyssal complex. They represent a known, but uncommon, type of deposit; relative to other commonly described volcanic-related uranium deposits, they are young, well-exposed and well-documented. Hydrothermal uranium-bearing quartz and fluorite veins are exposed over a 300 m vertical range in the mines. Molybdenum, as jordisite (amorphous MoS2, together with fluorite and pyrite, increase with depth, and uranium decreases with depth. The veins cut 23-Ma quartz monzonite, 20-Ma granite, and 19-Ma rhyolite ash-flow tuff. The veins formed at 19-18 Ma in a 1 km2 area, above a cupola of a composite, recurrent, magma chamber at least 24 ?? 5 km across that fed a sequence of 21- to 14-Ma hypabyssal granitic stocks, rhyolite lava flows, ash-flow tuffs, and volcanic domes. Formation of the Central Mining Area began when the intrusion of a rhyolite stock, and related molybdenite-bearing, uranium-rich, glassy rhyolite dikes, lifted the fractured roof above the stock. A breccia pipe formed and relieved magmatic pressures, and as blocks of the fractured roof began to settle back in place, flat-lying, concave-downward, 'pull-apart' fractures were formed. Uranium-bearing, quartz and fluorite veins were deposited by a shallow hydrothermal system in the disarticulated carapace. The veins, which filled open spaces along the high-angle fault zones and flat-lying fractures, were deposited within 115 m of the ground surface above the concealed rhyolite stock. Hydrothermal fluids with temperatures near 200??C, ??18OH2O ~ -1.5, ?? -1.5, ??DH2O ~ -130, log fO2 about -47 to -50, and pH about 6 to 7, permeated the fractured rocks; these fluids were rich in fluorine, molybdenum, potassium, and hydrogen sulfide, and contained uranium as fluoride complexes. The hydrothermal fluids reacted with the wallrock resulting in

  3. Coeval Formation of Zircon Megacrysts and Host Magmas in the Eifel Volcanic Field (Germany) Based on High Spatial Resolution Petrochronology

    Science.gov (United States)

    Schmitt, Axel; Klitzke, Malte; Gerdes, Axel; Ludwig, Thomas; Schäfer, Christof

    2017-04-01

    Zircon megacrysts (approx. 0.5-6 mm in diameter) from the Quaternary West and East Eifel volcanic fields, Germany, occur as euhedral crystals in porous K-spar rich plutonic ejecta clasts, and as partially resorbed xenocrysts in tephrite lava. Their relation to the host volcanic rocks has remained contentious because the dominantly basanitic to phonolitic magma compositions in the Eifel are typically zircon undersaturated. We carried out a detailed microanalytical study of zircon megacrysts from seven locations (Emmelberg and Rockeskyll in the West Eifel; Bellerberg, Laacher See, Mendig, Rieden, and Wehr in the East Eifel). Crystals were embedded in epoxy, sectioned to expose interiors through grinding with abrasives, diamond-polished, and mapped by optical microscopy, backscattered electron, and cathodoluminescence imaging. Subsequently, isotope-specific analysis using secondary ionization mass spectrometry (SIMS) and laser ablation inductively coupled mass spectrometry (LA-ICP-MS) was carried out placing 100 correlated spots on 20 selected crystals. Concordant U-Th disequilibrium and U-Pb ages determined by SIMS are between ca. 430 ka (Rieden) and 170 ka (Mendig) and indicate that the megacryst zircons crystallized almost always briefly before eruption. A significant gap between zircon megacryst crystallization (ca. 230 ka) and eruption (ca. 45 ka) ages was only detected for the Emmelberg location. SIMS trace element abundances (e.g., rare earth elements) vary by orders-of-magnitude and correlate with domain boundaries visible in cathodoluminescence; trace element patterns match those reported for zircon from syenitic origins. Isotopic compositions are homogeneous within individual crystals, but show some heterogeneity between different crystals from the same locality. Average isotopic values (δ18O SMOW = +5.3±0.6 ‰ by SIMS; present-day ɛHf = +1.7±2.5 ‰ by LA-ICP-MS; 1 standard deviation), however, are consistent with source magmas being dominantly mantle

  4. Paleomagnetism and Rock Magnetic Properties from Quaternary Lavas and Tuffs of the Yellowstone Plateau Volcanic Field

    Science.gov (United States)

    Harlan, S. S.; Morgan, L. A.

    2008-12-01

    We report paleomagnetic and rock magnetic from rhyolite lava flows, ignimbrites, and basalt flows associated with the Yellowstone Caldera, within and surrounding Yellowstone National Park. These data were collected in order to understand sources of magnetic variations observed in high resolution aeromagnetic data reported by Finn and Morgan (2002), and to better understand the evolution of the Yellowstone magmatic system. Most paleomagnetic samples are from volcanic rocks of the third eruptive cycle (1.2 Ma to 0.070 Ma), including the ca. 0.640 Ma Lava Creek Tuff, postcaldera rhyolite flows, and contemporaneous marginal or post-caldera basalt flows. Magnetic intensities for samples ranged from 0.12 A/m to 5.9 A/m, with volume susceptibilities of 2.14x10-4 to 1.45x10-3 SI; Q ratios range from 0.67 to 23.8. As expected, most sites yield well-defined paleomagnetic directions of north declination and moderate positive inclination consistent with remanence acquisition during the Brunhes polarity chron. However, a few sites from older units such as the rhyolites of the Harlequin Lake (0.839 ± 0.007 Ma) and Lewis Canyon (0.853 ± 0.008 Ma) flows, and the basalts from the Junction Butte flow (at Tower Falls, 2.16 ± 0.04 Ma) and Hepburn Mesa (2.2 Ma) yield reverse polarity magnetizations (40Ar/39Ar dates from Obradovich, 1992, and Harlan, unpublished (Hepburn Mesa flow)). Rock magnetic behavior, including high coercivities during AF demagnetization, high laboratory unblocking temperatures, and susceptibility vs. temperature determinations indicate that remanence in the rhyolitic samples is carried by a combination of single or pseudo-single domain magnetite and/or hematite; in the basalt flows magnetite and high-Ti titanomagnetite carrys the remanence. Paleomagnetic results from 46 sites in 27 separate flows yields a grand mean direction with a declination of 356.9° and inclination of 61.9° (k = 35.2, α95 = 4.8°). VGPs calculated from the site-mean directions yield a

  5. Volcanic-plutonic connections and metal fertility of highly evolved magma systems: A case study from the Herberton Sn-W-Mo Mineral Field, Queensland, Australia

    Science.gov (United States)

    Cheng, Yanbo; Spandler, Carl; Chang, Zhaoshan; Clarke, Gavin

    2018-03-01

    Understanding the connection between the highly evolved intrusive and extrusive systems is essential to explore the evolution of high silicic magma systems, which plays an important role in discussions of planetary differentiation, the growth of continents, crustal evolution, and the formation of highly evolved magma associated Sn-W-Mo mineral systems. To discern differences between "fertile" and "non-fertile" igneous rocks associated with Sn-W-Mo mineralization and reveal the genetic links between coeval intrusive and extrusive rocks, we integrate whole rock geochemistry, geochronology and Hf isotope signatures of igneous zircons from contemporaneous plutonic and volcanic rocks from the world-class Herberton Mineral Field of Queensland, Australia. The 310-300 Ma intrusive rocks and associated intra-plutonic W-Mo mineralization formed from relatively oxidized magmas after moderate degrees of crystal fractionation. The geochemical and isotopic features of the coeval volcanic succession are best reconciled utilizing the widely-accepted volcanic-plutonic connection model, whereby the volcanic rocks represent fractionated derivatives of the intrusive rocks. Older intrusions emplaced at 335-315 Ma formed from relatively low fO2 magmas that fractionated extensively to produce highly evolved granites that host Sn mineralization. Coeval volcanic rocks of this suite are compositionally less evolved than the intrusive rocks, thereby requiring a different model to link these plutonic-volcanic sequences. In this case, we propose that the most fractionated magmas were not lost to volcanism, but instead were effectively retained at the plutonic level, which allowed further localized build-up of volatiles and lithophile metals in the plutonic environment. This disconnection to the volcanism and degassing may be a crucial step for forming granite-hosted Sn mineralization. The transition between these two igneous regimes in Herberton region over a ∼30 m.y. period is attributed to

  6. Field screening of water quality, bottom sediment, and biota associated with irrigation drainage in the Yuma Valley, Arizona, 1995

    Science.gov (United States)

    Tadayon, Saeid; King, K.A.; Andrews, Brenda; Roberts, William

    1997-01-01

    Because of concerns expressed by the U.S. Congress and the environmental community, the Department of the Interior began a program in late 1985 to identify the nature and extent of water-quality problems induced by irrigation that might exist in the western States. Surface water, bottom sediment, and biota were collected from March through September 1995 along the lower Colorado River and in agricultural drains at nine sites in the Yuma Valley, Arizona, and analyzed for selected inorganic and organic constituents. Analyses of water, bottom sediment, and biota were completed to determine if irrigation return flow has caused, or has the potential to cause, harmful effects on human health, fish, and wildlife in the study area. Concentrations of dissolved solids in surface-water samples collected in March generally did not vary substantially from surface-water samples collected in June. Concentrations of dissolved solids ranged from 712 to 3,000 milligrams per liter and exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level of 500 milligrams per liter for drinking water. Concentrations of chloride in 9 of 18 water samples and concentrations of sulfate in 16 of 18 water samples exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level of 250 milligrams per liter for drinking water. Calcium and sodium were the dominant cations, and chloride and sulfate were the dominant anions. The maximum selenium concentration of 8 micrograms per liter exceeded the U.S. Environmental Protection Agency aquatic-life chronic criterion of 5 micrograms per liter. Concentrations of lead in 7 of 18 water samples and concentrations of mercury in 4 of 18 water samples exceeded the aquatic-life cronic criteria of 3.2 and 0.012 micrograms per liter, respectively. Concentrations of antimony, beryllium, cadmium, and silver in the water samples were below analytical reporting limits. Arsenic was detected in 3 of 9 bottom-sediment samples

  7. Carbonatite associated with ultramafic diatremes in the Avon Volcanic District, Missouri, USA: Field, petrographic, and geochemical constraints

    Science.gov (United States)

    Shavers, Ethan J.; Ghulam, Abduwasit; Encarnacion, John; Bridges, David L.; Luetkemeyer, P. Benjamin

    2016-04-01

    Here we report field, petrographic, and geochemical analyses of the southeast Missouri Avon Volcanic District intrusive rocks and present the first combined textural and geochemical evidence for the presence of a primary magmatic carbonatite phase among ultramafic dikes, pipes, and diatremes of olivine melilitite, alnöite, and calciocarbonatite. The δ13CVPDB values measured for primary calciocarbonatite as well as carbonates in olivine melilitite and alnöite rocks range from - 3.8‰ to - 8.2‰, which are within the typical range of mantle values and are distinct from values of the carbonate country rocks, 0.0‰ to - 1.3‰. The carbonate oxygen isotope compositions for the intrusive lithologies are in the range of 21.5‰ to 26.2‰ (VSMOW), consistent with post-emplacement low temperature hydrothermal alteration or kinetic fractionation effects associated with decompression and devolatilization. Metasomatized country rock and breccia-contaminated igneous lithologies have carbonate δ13CVPDB values gradational between primary carbonatite values and country rock values. Unaltered sedimentary dolomite breccia and mafic spheroids entrained by calciocarbonatite and the lack of microstratigraphic crystal growth typical of carbonate replacement, also exclude the possibility of hydrothermal replacement as the cause of the magmatic-textured carbonates. Rare earth element (REE) patterns for the alnöite, olivine melilitite, and carbonatite are similar to each other with strong light REE enrichment and heavy REE depletion relative to MORB. These patterns are distinct from those of country rock rhyolite and sedimentary carbonate. These data suggest that rocks of the Avon Volcanic District represent a single ultramafic-carbonatite intrusive complex possibly derived from a single mantle source.

  8. Mapping the edge of the Cerros del Rio volcanic field, New Mexico: a piece of the puzzle to understanding a potential geothermal resource

    Science.gov (United States)

    Pellerin, L.; Gallegos, M.; Goebel, M.; Murphy, B. S.; Smith, J.; Soto, D.; Swiatlowski, J.; Volk, C.; Welch, M.; Feucht, D. W.; Hollingshaus, B.; Bedrosian, P. A.; McPhee, D. K.

    2012-12-01

    The Cerros del Rio volcanic field located west of Santa Fe, New Mexico spans the southwestern part of the Espanola Basin with the Rio Grande to the west. Underlying the volcanics are the Santa Fe Group sediments, which contain the Ancha Formation, an important aquifer in the region. High temperature gradients in water wells reveal a potential geothermal prospect. In 2012 the Summer of Applied Geophysical Experience (SAGE) program acquired transient electromagnetic (TEM), audiomagnetotelluric (AMT), gravity and ground magnetic data to determine the buried eastern margin of the volcanic field and the connectivity related to the underlying sediments. The roughly EW 5-km long transect was sited from USGS aeromagnetic data to cross the boundary of the Cerros del Rio volcanic field. TEM data collected at ten stations, at 200-400 m spacing, along the transect employed an in-loop configuration with a square 100 m x 100 m transmitter loop and both a Zonge receiver coil and a 5 m square receiver loop. The 5 m loop allowed for the recovery of early-time data that was saturated when using the Zonge coil. AMT data were acquired at eight stations, at 400-500 m spacing, using the Geometric Stratagem system recording from 92 kHz to 10 Hz; a horizontal magnetic dipole transmitter was used to augment low signal strength at around 1 kHz. Gravity data along the profile were acquired using CG-3 and CG-5 Scintrex gravimeters with a station interval >250 m. Magnetic data were acquired with a Geometrics Cesium vapor G-858 magnetometer for about 3500 m along the profile at a 0.5 second sampling rate. Two volcanic flows interbedded with Ancha Formation and overlying Santa Fe Group sediments were identified in both the TEM and AMT modeling. High surface resistivity zones (>300 ohm-m) with depths ranging from ~100 to 300 m define the volcanic flows and correspond to high densities (2.3 to 2.55 g/cm3), while low resistivity zones (<30 ohm-m) correspond to lower densities (~2.1 g/cm3). High

  9. Database for the Quaternary and Pliocene Yellowstone Plateau volcanic field of Wyoming, Idaho, and Montana (Database for Professional Paper 729-G)

    Science.gov (United States)

    Koch, Richard D.; Ramsey, David W.; Christiansen, Robert L.

    2011-01-01

    The superlative hot springs, geysers, and fumarole fields of Yellowstone National Park are vivid reminders of a recent volcanic past. Volcanism on an immense scale largely shaped the unique landscape of central and western Yellowstone Park, and intimately related tectonism and seismicity continue even now. Furthermore, the volcanism that gave rise to Yellowstone's hydrothermal displays was only part of a long history of late Cenozoic eruptions in southern and eastern Idaho, northwestern Wyoming, and southwestern Montana. The late Cenozoic volcanism of Yellowstone National Park, although long believed to have occurred in late Tertiary time, is now known to have been of latest Pliocene and Pleistocene age. The eruptions formed a complex plateau of voluminous rhyolitic ash-flow tuffs and lavas, but basaltic lavas too have erupted intermittently around the margins of the rhyolite plateau. Volcanism almost certainly will recur in the Yellowstone National Park region. This digital release contains all the information used to produce the geologic maps published as plates in U.S. Geological Survey Professional Paper 729-G (Christiansen, 2001). The main component of this digital release is a geologic map database prepared using geographic information systems (GIS) applications. This release also contains files to view or print the geologic maps and main report text from Professional Paper 729-G.

  10. High-resolution 40Ar/39Ar geochronology of volcanic rocks from the Siebengebirge (Central Germany)—Implications for eruption timescales and petrogenetic evolution of intraplate volcanic fields

    Science.gov (United States)

    Przybyla, Thomas; Pfänder, Jörg A.; Münker, Carsten; Kolb, Melanie; Becker, Maike; Hamacher, Uli

    2017-11-01

    A key parameter in understanding mantle dynamics beneath continents is the temporal evolution of intraplate volcanism in response to lithospheric thinning and asthenospheric uplift. To contribute to a better understanding of how intraplate volcanic fields evolve through time, we present a high precision 40Ar/39Ar age dataset for volcanic rocks from the Siebengebirge volcanic field (SVF) from central Germany, one of the best studied and compositionally most diverse intraplate volcanic fields of the Cenozoic Central European Volcanic Province (CEVP). Petrological and geochemical investigations suggest that the formation of the different rock types that occur in the SVF can be explained by a combination of assimilation and fractional crystallisation processes, starting from at least two different parental magmas with different levels of silica saturation (alkali basaltic and basanitic), and originating from different mantle sources. These evolved along two differentiation trends to latites and trachytes, and to tephrites and tephriphonolites, respectively. In contrast to their petrogenesis, the temporal evolution of the different SVF suites is poorly constrained. Previous K/Ar ages suggested a time of formation between about 28 and 19 Ma for the mafic rocks, and of about 27 to 24 Ma for the differentiated rocks. Our results confirm at high precision that the differentiated lithologies of both alkaline suites (40Ar/39Ar ages from 25.3 ± 0.2 Ma to 25.9 ± 0.3 Ma) erupted contemporaneously within a very short time period of 0.6 Ma, whereas the eruption of mafic rocks (basanites) lasted at least 8 Ma (40Ar/39Ar ages from 22.2 ± 0.2 Ma to 29.5 ± 0.3 Ma). This implies that felsic magmatism in the central SVF was likely a single event, possibly triggered by an intense phase of rifting, and that ongoing melting and eruption of mostly undifferentiated mafic lavas dominate the > 8 Ma long magmatic history of this region. Among the mafic lavas, most basanites and tephrites

  11. Examining Volcanic Terrains Using In Situ Geochemical Technologies; Implications for Planetary Field Geology

    Science.gov (United States)

    Young, K. E.; Bleacher, J. E.; Evans, C. A.; Rogers, A. D.; Ito, G.; Arzoumanian, Z.; Gendreau, K.

    2015-01-01

    Regardless of the target destination for the next manned planetary mission, the crew will require technology with which to select samples for return to Earth. The six Apollo lunar surface missions crews had only the tools to enable them to physically pick samples up off the surface or from a boulder and store those samples for return to the Lunar Module and eventually to Earth. Sample characterization was dependent upon visual inspection and relied upon their extensive geology training. In the four decades since Apollo however, great advances have been made in traditionally laboratory-based instrument technologies that enable miniaturization to a field-portable configuration. The implications of these advancements extend past traditional terrestrial field geology and into planetary surface exploration. With tools that will allow for real-time geochemical analysis, an astronaut can better develop a series of working hypotheses that are testable during surface science operations. One such technology is x-ray fluorescence (XRF). Traditionally used in a laboratory configuration, these instruments have now been developed and marketed commercially in a field-portable mode. We examine this technology in the context of geologic sample analysis and discuss current and future plans for instrument deployment. We also discuss the development of the Chromatic Mineral Identification and Surface Texture (CMIST) instrument at the NASA Goddard Space Flight Center (GSFC). Testing is taking place in conjunction with the RIS4E (Remote, In Situ, and Synchrotron Studies for Science and Exploration) SSERVI (Solar System Exploration and Research Virtual Institute) team activities, including field testing at Kilauea Volcano, HI..

  12. Geologic Investigations Spurred by Analog Testing at the 7504 Cone-SP Mountain Area of the San Francisco Volcanic Field

    Science.gov (United States)

    Eppler, Dean B.

    2015-01-01

    The SP Mountain area of the San Francisco Volcanic Field, AZ, has been used as an analog mission development site for NASA since 1998. This area consists of basaltic cinder cones, lava flows and maar craters that have been active since mid-Miocene, with the youngest events occurring within the last 10,000 years. The area has been used because its geologic and topographic resemblance to lunar and Martian terrains provides an ideal venue for testing hardware and science operations practices that might be employed on planetary surfaces, as well as training astronauts in field geology. Analog operations have often led to insights that spurred new scientific investigations. Most recently, an investigation of the 7504 cone was initiated due to perceptions that Apollo-style traverse plans executed during the Desert RATS 2010 mission had characterized the area incorrectly, leading to concerns that the Apollo traverse planning process was scientifically flawed. This investigation revealed a complex history of fissure eruptions of lava and cinders, cinder cone development, a cone-fill-and-spill episode, extensive rheomorphic lava flow initiation and emplacement, and cone sector collapse that led to a final lava flow. This history was not discernible on pre-RATS mission photogeology, although independent analysis of RATS 2010 data and samples develped a "75% complete solution" that validated the pre-RATS mission planning and Apollo traverse planning and execution. The study also pointed out that the development of scientific knowledge with time in a given field area is not linear, but may follow a functional form that rises steeply in the early period of an investigation but flattens out in the later period, asymptotically approaching a theoretical "complete knowledge" point that probably cannot be achieved. This implies that future human missions must be prepared to shift geographic areas of investigation regularly if significant science returns are to be forthcoming.

  13. Compound maar crater and co-eruptive scoria cone in the Lunar Crater Volcanic Field (Nevada, USA)

    Science.gov (United States)

    Amin, Jamal; Valentine, Greg A.

    2017-06-01

    Bea's Crater (Lunar Crater Volcanic Field, Nevada, USA) consists of two coalesced maar craters with diameters of 440 m and 1050 m, combined with a co-eruptive scoria cone that straddles the northeast rim of the larger crater. The two craters and the cone form an alignment that parallels many local and regional structures such as normal faults, and is interpreted to represent the orientation of the feeder dyke near the surface. The maar formed among a dense cluster of scoria cones; the cone-cluster topography resulted in crater rim that has a variable elevation. These older cones are composed of variably welded agglomerate and scoria with differing competence that subsequently affected the shape of Bea's Crater. Tephra ring deposits associated with phreatomagmatic maar-forming eruptions are rich in basaltic lithics derived from clasts, consistent with ejection from relatively shallow explosions although a diatreme might extend to deeper levels beneath the maar. Interbedding of deposits on the northeastern cone and in the tephra ring record variations in the magmatic volatile driven and phreatomagmatic eruption styles in both space and time along a feeder dike.

  14. Effect of volcanic dykes on coastal groundwater flow and saltwater intrusion: A field-scale multiphysics approach and parameter evaluation

    Science.gov (United States)

    Comte, J.-C.; Wilson, C.; Ofterdinger, U.; González-Quirós, A.

    2017-03-01

    Volcanic dykes are common discrete heterogeneities in aquifers; however, there is a lack of field examples of, and methodologies for, comprehensive in situ characterization of their properties with respect to groundwater flow and solute transport. We have applied an integrated multiphysics approach to quantify the effect of dolerite dykes on saltwater intrusion in a coastal sandstone aquifer. The approach involved ground geophysical imaging (passive magnetics and electrical resistivity tomography), well hydraulic testing, and tidal propagation analysis, which provided constraints on the geometry of the dyke network, the subsurface saltwater distribution, and the sandstone hydrodynamic properties and connectivity. A three-dimensional variable-density groundwater model coupled with a resistivity model was further calibrated using groundwater and geophysical observations. A good agreement of model simulations with tide-induced head fluctuations, geophysically derived pore water salinities, and measured apparent resistivities was obtained when dykes' hydraulic conductivity, storativity, and effective porosity are respectively about 3, 1, and 1 orders of magnitude lower than the host aquifer. The presence of the dykes results in barrier-like alterations of groundwater flow and saltwater intrusion. Preferential flow paths occur parallel to observed dyke orientations. Freshwater inflows from upland recharge areas concentrate on the land-facing side of the dykes and saltwater penetration is higher on their sea-facing side. This has major implications for managing groundwater resources in dyke-intruded aquifers, including in coastal and island regions and provides wider insights on preferential pathways of groundwater flow and transport in highly heterogeneous aquifer systems.

  15. Pleniglacial sedimentation process reconstruction on laminated lacustrine sediments from lava-dammed Paleolake Alf, West Eifel Volcanic Field (Germany)

    Science.gov (United States)

    Eichhorn, Luise; Pirrung, Michael; Zolitschka, Bernd; Büchel, Georg

    2017-09-01

    Differentiating between regularly seasonal, irregular and event-based clastic sedimentation is difficult if sedimentation structures resemble and dating methods are imprecise. In this study - clastic light and dark laminae from lava-dammed Paleolake Alf in the Late Pleistocene in the Quaternary West Eifel Volcanic Field are analyzed to clarify how they formed and if they are of annual origin and comparable to assumed periglacial varves from neighboring Lake Holzmaar. Therefore, a multiproxy approach is applied combining sediment thin section analysis which focuses on composition and structure with 14C dates. The results are compared to recently-formed annually-laminated clastic sediments of, e.g., the High Canadian Arctic. Observed sedimentation structures reveal sediment delivery by over- and interflows and deposition from suspension forming two characteristic microfacies: Type I graded laminae and Type II laminae with graded sublayers. Additionally, erosional bases and event deposits indicate episodic underflows. Thus, lamination is potentially seasonal but is significantly veiled by extreme runoff causing erosion and resuspension processes or a mixed water body preventing sediment delivery into the lake basin. However, sedimentation processes between watershed and lake could be reconstructed by comparing recent and paleosediment structures.

  16. 39Ar/40Ar Chronology and Volumes of Eruptive Products Over the Last 1 Myr in the Tequila Volcanic Field, Jalisco, Mexico

    Science.gov (United States)

    Lewis-Kenedi, C. B.; Lange, R. A.; Hall, C. M.; Delgado-Granados, H.

    2002-12-01

    The Tequila volcanic field, located within the western Trans-Mexican arc, covers an area of 1036 km2 and includes a central, andesitic stratocone, Volc\\­_{a}n Tequila, as well as cinder cones, domes, and fissure-fed flows. Sixty-nine high precision 39Ar-40Ar dates reveal that major activity in the Tequila volcanic field began at approximately 1 Ma. From 1 Ma to 200 ka, rhyolite (> 73 wt. % SiO2) and alkali basalt (­š 51 wt. % SiO2) were the only compositions erupted in significant volumes (29 +/- 5.7 km3 and 12 +/- 1.2 km3, respectively). At approximately 200 ka, the andesite comprising Volc\\­_{a}n Tequila erupted within 30-40 kyr, producing a volume of 30 +/- 2.0 km3. Additional andesitic flows (11 +/- 1.4 km3) erupted to the northwest and southeast of the stratocone between 140 and 20 ka. The total volume of dacite that erupted at the Tequila volcanic field is small (1.3 +/- 0.03 km3) and occurred largely (88%) within the last 70 kyrs. Unlike the andesites and dacites, the basalts and rhyolites did not erupt within narrow time intervals, but extruded over the entire last 1 Myr, producing a total volume of 12.6 +/- 1.2 km3 and 32 +/- 6.1 km3, respectively. This detailed eruptive history, combined with the observed phenocryst assemblages (0-10 vol. %) in the small-volume andesite, dacite, and alkali basalt flows, suggest that they were erupted directly from the lower (or middle) crust, without prior storage in an upper crustal chamber. In contrast, the voluminous burst of andesitic volcanism that produced the phenocryst-rich (35-45 vol. %) lavas of Volc\\­_{a}n Tequila was likely fed from a short-lived (­š 40 kyrs) upper crustal chamber. This scenario is supported by the complex, disequilibrium textures seen in the phenocryst assemblage of the Volc\\­_{a}n Tequila lavas, indicative of magma mingling within an upper crustal chamber (Wallace and Carmichael, 1994). The total volume of erupted material at the Tequila volcanic field is 89 +/- 12 km3, of which

  17. Late Pleistocene to Holocene soil development and environments in the Long Gang Volcanic Field area, Jilin Province, NE China

    Science.gov (United States)

    Sauer, Daniela; Zhang, Xinrong; Knöbel, Jette; Maerker, Lutz

    2014-05-01

    Late Pleistocene to Holocene shifts of climate and vegetation in the Long Gang Volcanic Field in NE China have been reconstructed, e. g. by Steblich et al. (2009), based on Maar lake sediment cores. In this study, we investigated soil development during the Late Pleistocene and Holocene and linked it to the climate and vegetation reported in the literature. Three pedons were described and analyzed on a crater wall surrounding a maar. The lower part of the slope is covered by basic pyroclastics that are obviously younger than the maar itself. Pedon 1 is located on the upper slope, where the younger pyroclastics are not present; thus it developed over the entire Holocene and part of the Late Pleistocene. Pedon 2 is on the toe slope and developed from the young basic pyroclastics. Vegetation remains, charred by fire that was caused by the volcanic ash fall, were found in the lowermost part of the pyroclastics layer, on top of a paleosol. Charcoal fragments were dated to 18950-18830 cal BP (using INTCAL 09). Thus, pedon 2 developed since around 18.9 ka BP, whereas the development of the paleosol that was buried under the pyroclastics (pedon 3), was stopped at this time. Pedons 1 and 2 are Vitric Andosols, developed mainly from basic pyroclastics, as evidenced by the composition of rock fragments in the soils, comprising 78 / 81 mass % lapilli and 22 / 19 mass % gneiss fragments, respectively. Pedon 3 is a Cutanic Luvisol (Chromic) that developed entirely from gneiss fragments produced by the maar explosion. Lab data suggest increasing intensity of pedogenesis in the direction: Pedon 3 (paleosol) climate than the two yellowish-brown surface soils. Since the morphology of the paleosol clearly reflects interglacial climatic conditions and forest cover, it most likely started developing during the Eemian. Steblich et al. (2009) reconstructed for the period 16.7-14.45 ka BP steppe with Betula (and minor proportions of Larix, Alnus, Picea and Salix). We assume a similar

  18. Inferring Shallow Subsurface Density Structure from Surface and Underground Gravity Measurements: Calibrating Models for Relatively Undeformed Volcanic Strata at the Jemez Volcanic Field, New Mexico, USA

    Science.gov (United States)

    Roy, Mousumi; Lewis, Megan; Johnson, Alex; George, Nicolas; Rowe, Charlotte; Guardincerri, Elena

    2017-12-01

    Imaging shallow subsurface density structure is an important goal in a variety of applications, from hydrogeology to seismic and volcanic hazard assessment. We assess the effectiveness of surface and subsurface gravity measurements in estimating the density structure of a well-characterized rock volume: the mesa (a small, flat-topped plateau) upon which the town of Los Alamos, New Mexico, USA is located. Our gravity measurements were made on the mesa surface above a horizontal tunnel and underground, within the tunnel. We demonstrate that, in the absence of other geophysical data such as seismic data or muon attenuation, subsurface (tunnel) gravity measurements are critical to accurately recovering geologic structure. Without the tunnel data, our resolution is limited to roughly the surface gravity station spacing, but by including the tunnel data we can resolve structure to a depth of 10 times the surface gravity station spacing. Densities were obtained using both forward modeling and a Bayesian inverse modeling approach, incorporating relevant constraints from geologic observations. We find that Bayesian inversion, with geologically relevant prior, is a superior approach to the forward models in terms of both robustness and efficiency and correctly predicts the orientation and elevation of important geologic features.

  19. 3-D Waveguide Effects of Topographical Structural Variation on Full Waveform Propagation: 3-D Finite Difference Modeling Comparisons with Field Data From Yuma Proving Ground, Arizona

    Science.gov (United States)

    Anderson, T. S.; Miller, R.; Greenfield, R.; Fisk, D.

    2002-12-01

    The propagation of seismic waves through regions of complex topography is not thoroughly understood. Surface waves, are of particular interest, as they are large in amplitude and can characterize the source depth, magnitude, and frequency content. The amplitude and frequency content of seismic waves that propagate in regions with large topographical variations are affected by both the scattering and blockage of the wave energy. The ability to predict the 3-d scattering due to topography will improve the understanding of both regional scale surface wave magnitudes, and refine surface wave discriminants as well as at the local scale (Smart Weapons Test Range, Yuma Proving Ground, Arizona. The result of the KGS characterization study is a high-resolution 3-d model that is used in our seismic simulations. The velocities Vs, Vp are calculated by tomography and refraction, attenuation coefficients estimated from the surface wave and from p-waves and are provided in a model with attributes resolved in 3-d to 0.5 meters. In the present work, we present comparisons of synthetic data with seismic data collected at the Smart Weapons Test Range to benchmark the accuracy achieved in simulating 3-d wave propagation in the vicinity of a topographical anomaly (trench). Synthetic seismograms are generated using a 3-d 8th order staggered grid visco-elastic finite difference code that accounts for topography. The geologic model is based on the Yuma site characterization. The size of these calculations required use of the DoD High Performance Computers and parallelized code. Results are compared with field data. Preliminary results show an excellent match with field data using the 3-d fdtd technique.

  20. Subterranean fragmentation of magma during conduit initiation and evolution in the shallow plumbing system of the small-volume Jagged Rocks volcanoes (Hopi Buttes Volcanic Field, Arizona, USA)

    Science.gov (United States)

    Re, Giuseppe; White, James D. L.; Muirhead, James D.; Ort, Michael H.

    2016-08-01

    Monogenetic volcanoes have limited magma supply and lack long-lived sustained magma plumbing systems. They erupt once, often from multiple vents and sometimes over several years, and are rarely or never re-activated. Eruptive behavior is very sensitive to physical processes (e.g., volatile exsolution, magma-water interaction) occurring in the later stages of magma ascent at shallow crustal depths (shapes, dense groundmasses, and composite clasts (loaded and cored). The extent of fragmentation and the formation of subterranean open space controlled the nature of the particles and the architecture and geometry of these conduit structures and their deposits.

  1. Voluminous low δ18O magmas in the late Miocene Heise volcanic field, Idaho: Implications for the fate of Yellowstone hotspot calderas

    Science.gov (United States)

    Bindeman, I.N.; Watts, K.E.; Schmitt, A.K.; Morgan, L.A.; Shanks, P.W.C.

    2007-01-01

    We report oxygen isotope compositions of phenocrysts and U-Pb ages of zircons in four large caldera-forming ignimbrites and post-caldera lavas of the Heise volcanic field, a nested caldera complex in the Snake River Plain, that preceded volcanism in Yellowstone. Early eruption of three normal δ18O voluminous ignimbrites with δ18Oquartz = 6.4‰ and δ18Ozircon = 4.8‰ started at Heise at 6.6 Ma, and was followed by a 2‰–3‰ δ18O depletion in the subsequent 4.45 Ma Kilgore caldera cycle that includes the 1800 km3 Kilgore ignimbrite, and post-Kilgore intracaldera lavas with δ18Oquartz = 4.3‰ and δ18Ozircon = 1.5‰. The Kilgore ignimbrite represents the largest known low-δ18O magma in the Snake River Plain and worldwide. The post-Kilgore low δ18O volcanism likely represents the waning stages of silicic magmatism at Heise, prior to the reinitiation of normal δ18O silicic volcanism 100 km to the northeast at Yellowstone. The occurrence of low δ18O magmas at Heise and Yellowstone hallmarks a mature stage of individual volcanic cycles in each caldera complex. Sudden shifts in δ18O of silicic magmas erupted from the same nested caldera complexes argue against any inheritance of the low δ18O signature from mantle or crustal sources. Instead, δ18O age trends indicate progressive remelting of low δ18O hydrothermally altered intracaldera rocks of previous eruptions. This trend may be generally applicable to older caldera complexes in the Snake River Plain that are poorly exposed.

  2. Evolution of silicic magma in the upper crust: the mid-Tertiary Latir volcanic field and its cogenetic granitic batholith, northern New Mexico, USA

    Science.gov (United States)

    Lipman, P.W.

    1988-01-01

    Structural and topographic relief along the eastern margin of the Rio Grande rift, northern New Mexico, provides a remarkable cross-section through the 26-Ma Questa caldera and cogenetic volcanic and plutonic rocks of the Latir field. Exposed levels increase in depth from mid-Tertiary depositional surfaces in northern parts of the igneous complex to plutonic rocks originally at 3-5 km depths in the S. Erosional remnants of an ash-flow sheet of weakly peralkaline rhyolite (Amalia Tuff) and andesitic to dactitic precursor lavas, disrupted by rift-related faults, are preserved as far as 45 km beyond their sources at the Questa caldera. Broadly comagmatic 26 Ma batholithic granitic rocks, exposed over an area of 20 by 35 km, range from mesozonal granodiorite to epizonal porphyritic granite and aplite; shallower and more silicic phases are mostly within the caldera. Compositionally and texturally distinct granites defined resurgent intrusions within the caldera and discontinuous ring dikes along its margins: a batholithic mass of granodiorite extends 20 km S of the caldera and locally grades vertically to granite below its flat-lying roof. A negative Bouguer gravity anomaly (15-20 mgal), which encloses exposed granitic rocks and coincides with boundaries of the Questa caldera, defined boundaries of the shallow batholith, emplaced low in the volcanic sequence and in underlying Precambrian rocks. Paleomagnetic pole positions indicate that successively crystallised granitic plutons cooled through Curie temperatures during the time of caldera formation, initial regional extension, and rotational tilting of the volcanic rocks. Isotopic ages for most intrusions are indistinguishable from the volcanic rocks. These relations indicate that the batholithic complex broadly represents the source magma for the volcanic rocks, into which the Questa caldera collapsed, and that the magma was largely liquid during regional tectonic disruption. -from Author

  3. Volcanic Gas

    Science.gov (United States)

    ... often escape continuously into the atmosphere from the soil, volcanic vents , fumaroles , and hydrothermal systems. By far the ... after falling into a snow depression surrounding a volcanic fumarole and filled ... of CO 2 gas in soils can also damage or destroy vegetation, as is ...

  4. A micro-scale investigation of melt production and extraction in the upper mantle based on silicate melt pockets in ultramafic xenoliths from the Bakony-Balaton Highland Volcanic Field (Western Hungary)

    DEFF Research Database (Denmark)

    Bali, Eniko; Zanetti, A.; Szabo, C.

    2008-01-01

    Mantle xenoliths in Neogene alkali basalts of the Bakony-Balaton Highland Volcanic Field (Western Hungary) frequently have melt pockets that contain silicate minerals, glass, and often carbonate globules. Textural, geochemical and thermobarometric data indicate that the melt pockets formed...

  5. Scallopleaf sage (salvia vaseyi: Lamiaceae) discovered in Arizona

    Science.gov (United States)

    Cain, J.W.; Felger, R.S.; Jansen, B.D.; Krausman, P.R.

    2010-01-01

    During the course of field work in Cabeza Prieta National Wildlife Refuge, southwestern Arizona, in 2003, James Cain and Brian Jansen collected Salvia vaseyi, previously known only from the western edge of the Sonoran Desert in California and Baja California. Our findings indicate this shrub might be more widespread in southwestern Arizona mountains. Salvia vaseyi in Arizona seems to represent a relict population. There are other shrubby Salvia in Arizona, but S. vaseyi is the most xeric-mhabiting species and has the narrowest ecological and geographical range.

  6. Potential of utilization of geothermal energy in Arizona

    Science.gov (United States)

    White, D. H.; Goldstone, L. A.

    1982-08-01

    Arizona is one of the fastest growing states in the United States. It is in the midst of the movement of the population of the United States from its cold regions to the warm Southwest. Being a hot, arid region, its electrical demand is nearly 50% higher in the peak hot summer months than that of the other 7 months. The major uncertainty of utilizing geothermal energy in Arizona is that very little exploration and development have occurred to date. The potential for utilizing geothermal energy in Arizona is good based on the fat thatthere are over 3000 thermal wells in Arizona out of a total of about 30,000 shallow irrigation wells that were examined. There is much young volcanic rock in Arizona. The combination of data from thermal wells, young volcanic rock, water geochemistry and other geological tools, indicate that there is a large geothermal resource throughout the southern half of the state. It is suggested that most of this resource is in the range of 500 to 1500 C, limiting its uses to direct heat utilization rather than for electric power generation.

  7. Inverse steptoes in Las Bombas volcano, as an evidence of explosive volcanism in a solidified lava flow field. Southern Mendoza-Argentina

    Science.gov (United States)

    Risso, Corina; Prezzi, Claudia; Orgeira, María Julia; Nullo, Francisco; Margonari, Liliana; Németh, Karoly

    2015-11-01

    Here we describe the unusual genesis of steptoes in Las Bombas volcano- Llancanelo Volcanic Field (LVF) (Pliocene - Quaternary), Mendoza, Argentina. Typically, a steptoe forms when a lava flow envelops a hill, creating a well-defined stratigraphic relationship between the older hill and the younger lava flow. In the Llancanelo Volcanic Field, we find steptoes formed with an apparent normal stratigraphic relationship but an inverse age-relationship. Eroded remnants of scoria cones occur in ;circular depressions; in the lava field. To express the inverse age-relationship between flow fields and depression-filled cones here we define this landforms as inverse steptoes. Magnetometric analysis supports this inverse age relationship, indicating reverse dipolar magnetic anomalies in the lava field and normal dipolar magnetization in the scoria cones (e.g. La Bombas). Negative Bouguer anomalies calculated for Las Bombas further support the interpretation that the scoria cones formed by secondary fracturing on already solidified basaltic lava flows. Advanced erosion and mass movements in the inner edge of the depressions created a perfectly excavated circular depression enhancing the ;crater-like; architecture of the preserved landforms. Given the unusual genesis of the steptoes in LVF, we prefer the term inverse steptoe for these landforms. The term steptoe is a geomorphological name that has genetic implications, indicating an older hill and a younger lava flow. Here the relationship is reversed.

  8. Volcanism in Eastern Africa

    Science.gov (United States)

    Cauthen, Clay; Coombs, Cassandra R.

    1996-01-01

    In 1891, the Virunga Mountains of Eastern Zaire were first acknowledged as volcanoes, and since then, the Virunga Mountain chain has demonstrated its potentially violent volcanic nature. The Virunga Mountains lie across the Eastern African Rift in an E-W direction located north of Lake Kivu. Mt. Nyamuragira and Mt. Nyiragongo present the most hazard of the eight mountains making up Virunga volcanic field, with the most recent activity during the 1970-90's. In 1977, after almost eighty years of moderate activity and periods of quiescence, Mt. Nyamuragira became highly active with lava flows that extruded from fissures on flanks circumscribing the volcano. The flows destroyed vast areas of vegetation and Zairian National Park areas, but no casualties were reported. Mt. Nyiragongo exhibited the same type volcanic activity, in association with regional tectonics that effected Mt. Nyamuragira, with variations of lava lake levels, lava fountains, and lava flows that resided in Lake Kivu. Mt. Nyiragongo, recently named a Decade volcano, presents both a direct and an indirect hazard to the inhabitants and properties located near the volcano. The Virunga volcanoes pose four major threats: volcanic eruptions, lava flows, toxic gas emission (CH4 and CO2), and earthquakes. Thus, the volcanoes of the Eastern African volcanic field emanate harm to the surrounding area by the forecast of volcanic eruptions. During the JSC Summer Fellowship program, we will acquire and collate remote sensing, photographic (Space Shuttle images), topographic and field data. In addition, maps of the extent and morphology(ies) of the features will be constructed using digital image information. The database generated will serve to create a Geographic Information System for easy access of information of the Eastem African volcanic field. The analysis of volcanism in Eastern Africa will permit a comparison for those areas from which we have field data. Results from this summer's work will permit

  9. Magma mixing in the Yellowstone Plateau Volcanic Field brought to light by X-ray microtomography and chemical analysis

    Science.gov (United States)

    Morgavi, Daniele; Arzilli, Fabio; Pritchard, Chad; Perugini, Diego; Mancini, Lucia; Larson, Peter; Dingwell, Donald Bruce

    2015-04-01

    The Yellowstone Plateau Volcanic Field (YVF) hosts at least four mixed magma complexes (Wilcox, 1944; Christiansen et al. 2007; Pritchard et al., 2013). We focus on the well-exposed Grizzly Lake complex. The main evidence of mixing in igneous rocks is commonly found as textural heterogeneities, such as i) flow structures, ii) magmatic enclaves and iii) physico-chemical disequilibria in melt and crystals (e.g. Perugini and Poli, 2012). From the geochemical and mineralogical point of view, quantitative and qualitative analyses of chemical and textural heterogeneity in mixed rocks highlights the important role of mixing dynamics in producing geochemical complexities and heterogeneities (Kratzmann et al., 2009). Zoned crystals and complex mineralogical associations are also considered, in many cases, evidence for mixing (e.g., Murphy at al., 1998; Couch et al., 2001). The generation of such textures implies the development of large contact interfaces between interacting melts/solids through which chemical and crystals exchanges are strongly amplified, leading to highly variable degrees of homogenization depending on differing element mobility (e.g. Perugini et al., 2006; 2008; De Campos et al., 2011; Perugini et al., 2012; Perugini and Poli, 2012; Morgavi et al., 2013a, b, c). Despite the abundant literature regarding magma mixing processes, only a few studies are focused on describing and quantifying the inter-relationship between the morphological texture of mixing patterns and the geochemical variability in mixed rhyolitic and basaltic complexes. (Freundt and Schmincke 1992; Morgavi et al., 2013 a, b, c;). Here, we combine two analytical techniques; X-ray computed microtomography and microprobe analysis to study the texture and chemistry of mixed rocks. Since mixed rocks of Grizzly Lake in the YVF had a very complex history and evolution, a significant amount of chemical measurements were needed to characterize the phases. In addition, X-ray microtomography was

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

    Science.gov (United States)

    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

  11. A fixed sublithospheric source for the late Neogene track of the Yellowstone hotspot: Implications of the Heise and Picabo volcanic fields

    Science.gov (United States)

    Anders, Mark H.; Rodgers, David W.; Hemming, Sidney R.; Saltzman, Janet; DiVenere, Victor J.; Hagstrum, Jonathan T.; Embree, Glenn F.; Walter, Robert C.

    2014-04-01

    The Heise and Picabo volcanic fields of eastern Idaho are part of the more extensive time-transgressive Yellowstone-Snake River Plain hotspot track. Calderas associated with these two silicic volcanic fields are buried under 1 to 3 km of younger basalt, so their locations and eruption record histories have been based on analysis of silicic units along the margins of the eastern Snake River Plain along with some limited geophysical data. A 1.5 km borehole penetrating through basalt into underlying silicic rocks provides new data we used to reassess caldera locations and the timing of eruptions of these volcanic fields. Using these new caldera locations, we calculate an extension-adjusted rate of 2.35 cm/yr for the North American plate over the last 6.66 m.y. and a velocity of 2.30 cm/yr over the 10.27 m.y. Recalculation of a previously determined plate velocity-based migration of the deformation field surrounding the eastern Snake River Plain yields an extension-adjusted rate of 2.38 ± 0.21 cm/yr. These migration rates all fall within the previously published range of North American plate velocities of 2.2 ± 0.8 cm/yr, 2.4 cm/yr, and 2.68 ± 0.78 cm/yr based on a global hot spot reference frame. The consistency of these rates suggest that over the last 10 m.y., the Yellowstone hot spot is fixed with respect to the motion of the North American plate and therefore consistent with a classical deep-sourced hotspot model.

  12. Surface heat flow and CO2 emissions within the Ohaaki hydrothermal field, Taupo Volcanic Zone, New Zealand

    Science.gov (United States)

    Rissmann, C.; Christenson, B.; Werner, C.; Leybourne, M.; Cole, J.; Gravley, D.

    2012-01-01

    Carbon dioxide emissions and heat flow have been determined from the Ohaaki hydrothermal field, Taupo Volcanic Zone (TVZ), New Zealand following 20a of production (116MW e). Soil CO2 degassing was quantified with 2663 CO2 flux measurements using the accumulation chamber method, and 2563 soil temperatures were measured and converted to equivalent heat flow (Wm -2) using published soil temperature heat flow functions. Both CO2 flux and heat flow were analysed statistically and then modelled using 500 sequential Gaussian simulations. Forty subsoil CO 2 gas samples were also analysed for stable C isotopes. Following 20a of production, current CO2 emissions equated to 111??6.7T/d. Observed heat flow was 70??6.4MW, compared with a pre-production value of 122MW. This 52MW reduction in surface heat flow is due to production-induced drying up of all alkali-Cl outflows (61.5MW) and steam-heated pools (8.6MW) within the Ohaaki West thermal area (OHW). The drying up of all alkali-Cl outflows at Ohaaki means that the soil zone is now the major natural pathway of heat release from the high-temperature reservoir. On the other hand, a net gain in thermal ground heat flow of 18MW (from 25MW to 43.3??5MW) at OHW is associated with permeability increases resulting from surface unit fracturing by production-induced ground subsidence. The Ohaaki East (OHE) thermal area showed no change in distribution of shallow and deep soil temperature contours despite 20a of production, with an observed heat flow of 26.7??3MW and a CO 2 emission rate of 39??3T/d. The negligible change in the thermal status of the OHE thermal area is attributed to the low permeability of the reservoir beneath this area, which has limited production (mass extraction) and sheltered the area from the pressure decline within the main reservoir. Chemistry suggests that although alkali-Cl outflows once contributed significantly to the natural surface heat flow (~50%) they contributed little (99% of the original CO 2

  13. Determine volcanic SO2 plume heights from satellite observations on a global scale using meteorological wind fields

    Science.gov (United States)

    Keicher, Viktoria; Hörmann, Christoph; Sihler, Holger; Platt, Ulrich; Warnach, Simon; Wagner, Thomas

    2017-04-01

    Satellite observations nowadays provide the global monitoring of volcanic plumes via sulphur dioxide (SO2) that is injected into the Earth's atmosphere. In turn, SO2 may lead to the formation of sulphate aerosols that can influence climate via direct and indirect radiative effects. The quantitative retrieval of SO2 requires an accurate plume height estimate in order to constrain total amounts for such events. However, especially for volcanic eruptions the vertical SO2 profile is typically unknown because of the initial conditions (e.g. individual explosions over an extended time period may lead to different gas layer altitudes). In recent years, satellite observations helped to improve global SO2 estimates, but still large uncertainties exist. Passive satellite remote sensing instruments in the UV/vis spectral range for example offer the opportunity to observe the location of a plume in two dimensions, but information about the corresponding height is limited. To gain further information about these plume profiles is not only interesting for the quantitative interpretation of satellite observations, but also in itself (e.g. to assess the radiative effect of volcanic plumes). Here, we present first results for a newly developed and systematic approach using the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) in combination with data for selected volcanic SO2 plumes originating from different volcanoes. The main plume informations retrieved by the satellite (i.e. plume location and observation time) are used as initial input parameters in order to estimate the plume's profile at the time of the measurements. The resulting trajectories can be used to constrain the eruption time and height. First comparisons show that retrieved results are in good agreement with direct local observations and reports. While the algorithm has been so far only applied to data from the second generation Global Ozone Monitoring Instrument (GOME-2), it may be

  14. Characteristics of zircons from volcanic ash-derived tonsteins in Late Permian coal fields of eastern Yunnan, China

    Science.gov (United States)

    Zhou, Y.; Ren, Y.; Tang, D.; Bohor, B.

    1994-01-01

    Kaolinitic tonsteins of altered synsedimentary volcanic ash-fall origin are well developed in the Late Permian coal-bearing formations of eastern Yunnan Province. Because of their unique origin, wide lateral extent, relatively constant thickness and sharp contacts with enclosing strata, great importance has been attached to these isochronous petrographic markers. In order to compare tonsteins with co-existing, non-cineritic claystones and characterize the individuality of tonsteins from different horizons for coal bed correlation, a semi-quantitative method was developed that is based on statistical analyses of the concentration and morphology of zircons and their spatial distribution patterns. This zircon-based analytical method also serves as a means for reconstructing volcanic ash-fall dispersal patterns. The results demonstrate that zircons from claystones of two different origins (i.e., tonstein and non-cineritic claystone) differ greatly in their relative abundances, crystal morphologies and spatial distribution patterns. Tonsteins from the same area but from different horizons are characterized by their own unique statistical patterns in terms of zircon concentration values and morphologic parameters (crystal length, width and the ratio of these values), thus facilitating stratigraphic correlation. Zircons from the same tonstein horizon also show continuous variation in these statistical patterns as a function of areal distribution, making it possible to identify the main path and direction in which the volcanic source materials were transported by prevailing winds. ?? 1994.

  15. Paleomagnetism and 40ar/39ar Geochronology of the Plio-Pleistocene Boring Volcanic Field: Implications for the Geomagnetic Polarity Time Scale

    Science.gov (United States)

    Hagstrum, J. T.; Fleck, R. J.; Evarts, R. C.; Calvert, A. T.; Conrey, R. M.

    2014-12-01

    The Boring volcanic field (BVF) in western Oregon and Washington has been the subject of a recently completed investigation that included detailed geologic mapping, petrographic and geochemical analyses, and 40Ar/39Ar geochronologic and paleomagnetic studies. At least 80 monogenetic volcanic centers compose the BVF, each of which erupted small volumes of magma ranging from basalt to mafic andesite over short intervals of time. More than 140 40Ar/39Ar determinations for lava flows and intrusions in the BVF range in age from ~3100 ka to ~60 ka. Oriented samples for paleomagnetic analysis were collected at an equivalent number of localities (>160) coincident with, or within the same unit proximal to, the geochronologic sampling sites. Based on the frequency distribution of ages, the most significant episodes of Boring volcanism occurred between 2700 and 2200 ka, 1700 and 500 ka, and 350 and 60 ka. A systematic determination of the BVF's eruptive history was undertaken mainly to assess its anomalous neotectonic setting west of the Cascade arc axis, as well as the magnitude of its concomitant volcanic hazards within the greater Portland and Vancouver metropolitan areas. Our paleomagnetic and geochronologic data, however, also have significant implications for the timing of geomagnetic field reversals and excursions during the Late Pliocene and Pleistocene epochs. The BVF data are more numerous higher in the section, and they capture transitional fields at two polarity boundaries allowing precise age determinations to be made for these reversals: the Brunhes-Matuyama transition is thus dated at 773±5 ka, and the upper Jaramillo-Matuyama transition at 973±6 ka. The lower Jaramillo-Matuyama transition occurred prior to 1068±8 ka, and the normal Cobb subchron must have occurred between reversed-polarity Matuyama flows dated at 1159±14 ka and 1207±6 ka. The lower Olduvai-Matuyama transition occurred prior to 1927±4 ka, and the Matuyama-Gauss transition prior to 2616

  16. A new high resolution total magnetic intensity data set of the Laacher See Volcano in the East-Eifel volcanic field, Germany

    Science.gov (United States)

    Goepel, A.; Queitsch, M.; Lonschinski, M.; Eitner, A.; Meisel, M.; Reißig, S.; Engelhardt, J.; Büchel, G.; Kukowski, N.

    2012-04-01

    The Laacher See Volcano (LSV) is part of the Quaternary East-Eifel volcanic field (EVF) located in the western part of Germany, where at least 103 eruptive centers have been identified. The Laacher See volcano explosively erupted about 6.3 km3 of phonolitic magma during a dominantly phreato-plinian eruption at about 12,900 BP. Despite numerous previous studies the eruptive history of LSV is not fully unveiled. For a better understanding of the eruptive history of LSV several geophysical methods, including magnetic, gravimetric and bathymetric surveys have been applied on and around Laacher See Volcano. Here we focus on the magnetic and bathymetric data. The presented high resolution magnetic data covering an area of about 25 km2 (20,000 sample points) and were collected using ground based proton magnetometers (GEM Systems GSM-19TGW, Geometrics G856) during several field campaigns. In addition, a magnetic survey on the lake was done using a non-magnetic boat as platform. The bathymetric survey was conducted on profiles (total length of 235 km) using an echo sounder GARMIN GPSMap 421. Depth data were computed to a bathymetric model on a 10 m spaced regular grid. A joint interpretation of magnetic, morphologic and bathymetric data allows us to search for common patterns which can be associated with typical volcanic features. From our data at least one new eruptive center and lava flow could be identified. Furthermore, the new data suggest that previously identified lava flows have not been accurately located.

  17. Coexistence of pumice and manganese nodule fields-evidence for submarine silicic volcanism in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; Sudhakar, M.

    -Fe, black colour, broken 63.65 n.d Mn-Fe within vesicles, broken 55 26 n d Maltana, Indonesia 65.38 15 50 Krakatau, Indonesia 67.64 15 79 1883 Krakatoa eruption 69 40 15 90 Pumice-like ejecta from Krakatoa 68 99 16 07 Samples 1-10: present study, 11... by ferroman- ganese oxides. Analyses of a few samples show averages of 61.67% SiO2 and 12.86% AI20 3 (Table 1). Pumice, mainly derived from explosive silicic volcanism, has a low specific gravity, the shape and size of the vesicles allowing them...

  18. Rocks of the Thirtynine Mile volcanic field as possible sources of uranium for epigenetic deposits in central Colorado, USA.

    Science.gov (United States)

    Dickinson, K.A.

    1987-01-01

    The most likely volcanic source rock for uranium in epigenetic deposits of the Tallahassee Creek uranium district and nearby areas is the Wall Mountain Tuff. The widespread occurrence of the Tuff, its high apparent original uranium content, approx 11 ppm, and its apparent loss of uranium from devitrification and other alteration suggest its role in providing that element. An estimate of the original Th/U ratio is based on the present thorium and uranium contents of the basal vitrophyre of the Tuff from Castle Rock Gulch, Hecla Junction and other areas.-from Author

  19. The polycyclic Lausche Volcano (Lausitz Volcanic Field) and its message concerning landscape evolution in the Lausitz Mountains (northern Bohemian Massif, Central Europe)

    Science.gov (United States)

    Wenger, Erik; Büchner, Jörg; Tietz, Olaf; Mrlina, Jan

    2017-09-01

    The Tertiary Lausitz Volcanic Field covers a broad area encompassing parts of Eastern Saxony (Germany), Lower Silesia (Poland) and North Bohemia (Czech Republic). Volcanism was predominantly controlled by the volcano-tectonic evolution of the Ohře Rift and culminated in the Lower Oligocene. This paper deals with the highest volcano of this area, the Lausche Hill (792.6 m a.s.l.) situated in the Lausitz Mountains. We offer a reconstruction of the volcanic edifice and its eruptive history. Its complex genesis is reflected by six different eruption styles and an associated petrographic variety. Furthermore, the Lausche Volcano provides valuable information concerning the morphological evolution of its broader environs. The remnant of an alluvial fan marking a Middle Paleocene-Lower Eocene (62-50 Ma) palaeo-surface is preserved at the base of the volcano. The deposition of this fan can be attributed to a period of erosion of its nearby source area, the Lausitz Block that has undergone intermittent uplift at the Lausitz Overthrust since the Upper Cretaceous. The Lausche Hill is one of at least six volcanoes in the Lausitz Mountains which show an eminent low level of erosion despite their Oligocene age and position on elevated terrain. These volcanoes are exposed in their superficial level which clearly contradicts their former interpretation as subvolcanoes. Among further indications, this implies that the final morphotectonic uplift of the Lausitz Mountains started in the upper Lower Pleistocene ( 1.3 Ma) due to revived subsidence of the nearby Zittau Basin. It is likely that this neotectonic activity culminated between the Elsterian and Saalian Glaciation ( 320 ka). The formation of the low mountain range was substantially controlled by the intersection of the Lausitz Overthrust and the Ohře Rift.

  20. The tropospheric processing of acidic gases and hydrogen sulphide in volcanic gas plumes as inferred from field and model investigations

    Directory of Open Access Journals (Sweden)

    A. Aiuppa

    2007-01-01

    Full Text Available Improving the constraints on the atmospheric fate and depletion rates of acidic compounds persistently emitted by non-erupting (quiescent volcanoes is important for quantitatively predicting the environmental impact of volcanic gas plumes. Here, we present new experimental data coupled with modelling studies to investigate the chemical processing of acidic volcanogenic species during tropospheric dispersion. Diffusive tube samplers were deployed at Mount Etna, a very active open-conduit basaltic volcano in eastern Sicily, and Vulcano Island, a closed-conduit quiescent volcano in the Aeolian Islands (northern Sicily. Sulphur dioxide (SO2, hydrogen sulphide (H2S, hydrogen chloride (HCl and hydrogen fluoride (HF concentrations in the volcanic plumes (typically several minutes to a few hours old were repeatedly determined at distances from the summit vents ranging from 0.1 to ~10 km, and under different environmental conditions. At both volcanoes, acidic gas concentrations were found to decrease exponentially with distance from the summit vents (e.g., SO2 decreases from ~10 000 μg/m3at 0.1 km from Etna's vents down to ~7 μg/m3 at ~10 km distance, reflecting the atmospheric dilution of the plume within the acid gas-free background troposphere. Conversely, SO2/HCl, SO2/HF, and SO2/H2S ratios in the plume showed no systematic changes with plume aging, and fit source compositions within analytical error. Assuming that SO2 losses by reaction are small during short-range atmospheric transport within quiescent (ash-free volcanic plumes, our observations suggest that, for these short transport distances, atmospheric reactions for H2S and halogens are also negligible. The one-dimensional model MISTRA was used to simulate quantitatively the evolution of halogen and sulphur compounds in the plume of Mt. Etna. Model predictions support the hypothesis of minor HCl chemical processing during plume transport, at least in cloud-free conditions. Larger

  1. Towards real-time eruption forecasting in the Auckland Volcanic Field: application of BET_EF during the New Zealand National Disaster Exercise `Ruaumoko'

    Science.gov (United States)

    Lindsay, Jan; Marzocchi, Warner; Jolly, Gill; Constantinescu, Robert; Selva, Jacopo; Sandri, Laura

    2010-03-01

    The Auckland Volcanic Field (AVF) is a young basaltic field that lies beneath the urban area of Auckland, New Zealand’s largest city. Over the past 250,000 years the AVF has produced at least 49 basaltic centers; the last eruption was only 600 years ago. In recognition of the high risk associated with a possible future eruption in Auckland, the New Zealand government ran Exercise Ruaumoko in March 2008, a test of New Zealand’s nation-wide preparedness for responding to a major disaster resulting from a volcanic eruption in Auckland City. The exercise scenario was developed in secret, and covered the period of precursory activity up until the eruption. During Exercise Ruaumoko we adapted a recently developed statistical code for eruption forecasting, namely BET_EF (Bayesian Event Tree for Eruption Forecasting), to independently track the unrest evolution and to forecast the most likely onset time, location and style of the initial phase of the simulated eruption. The code was set up before the start of the exercise by entering reliable information on the past history of the AVF as well as the monitoring signals expected in the event of magmatic unrest and an impending eruption. The average probabilities calculated by BET_EF during Exercise Ruaumoko corresponded well to the probabilities subjectively (and independently) estimated by the advising scientists (differences of few percentage units), and provided a sound forecast of the timing (before the event, the eruption probability reached 90%) and location of the eruption. This application of BET_EF to a volcanic field that has experienced no historical activity and for which otherwise limited prior information is available shows its versatility and potential usefulness as a tool to aid decision-making for a wide range of volcano types. Our near real-time application of BET_EF during Exercise Ruaumoko highlighted its potential to clarify and possibly optimize decision-making procedures in a future AVF eruption

  2. A Conceptual Model to Link Anomalously High Temperature Gradients in the Cerros del Rio Volcanic Field to Regional Flow in the Espanola Basin, New Mexico

    Science.gov (United States)

    Fillingham, E. J.; Keller, S. N.; McCullough, K. R.; Watters, J.; Weitering, B.; Wilce, A. M.; Folsom, M.; Kelley, S.; Pellerin, L.

    2015-12-01

    Temperature-depth well data along with electromagnetic (EM) data were collected by students of the Summer of Applied Geophysics Experience (SAGE) 2015 field season in the Espanola Basin, New Mexico. The data from this year, in addition to data acquired since 2013, were used to construct a conceptual east-west cross-section of the Espanola Basin and the adjacent highlands in order to evaluate the regional flow system. Vertical geothermal gradients from several monitoring wells were measured using a thermistor. Anomalously warm geothermal gradients were mapped in the Cerros del Rio volcanic field in the basin just east of the Rio Grande. Temperature gradients are up to 70℃/km, while the background geothermal gradients in the Rio Grande rift zone generally show 28℃-35℃/km. This anomaly extends to the Buckman well field, which supplies water to the city of Santa Fe. Overpumping of this well field has led to subsidence in the past. However, discharge temperature plots indicate that the temperature gradients of the Buckman field may be rebounding as pumping is reduced. Audiomagnetotelluric (AMT) and transient electromagnetic (TEM) data were acquired in the vicinity of three monitoring wells. TEM and AMT methods complement each other with the former having depths of investigation of less than ten to hundreds of meters and AMT having depths of investigation comparable to the wells deeper than 500m. These datasets were used collectively to image the subsurface stratigraphy and, more specifically, the hydrogeology related to shallow aquifers. The EM data collected at these wells showed a trend indicating a shallow aquifer with a shallower resistive layer of approximately 100 ohm-m at 70-100 meters depth. Beneath this resistive layer we resolved a more conductive, clay-rich layer of 10 ohm-m. These resistivity profiles compliment the electrical logs provided by Jet West, which indicate shallower sandstone interbedded with silt on top of more silt-dominant layers. Our

  3. Volcanic gas

    Science.gov (United States)

    McGee, Kenneth A.; Gerlach, Terrance M.

    1995-01-01

    In Roman mythology, Vulcan, the god of fire, was said to have made tools and weapons for the other gods in his workshop at Olympus. Throughout history, volcanoes have frequently been identified with Vulcan and other mythological figures. Scientists now know that the “smoke" from volcanoes, once attributed by poets to be from Vulcan’s forge, is actually volcanic gas naturally released from both active and many inactive volcanoes. The molten rock, or magma, that lies beneath volcanoes and fuels eruptions, contains abundant gases that are released to the surface before, during, and after eruptions. These gases range from relatively benign low-temperature steam to thick hot clouds of choking sulfurous fume jetting from the earth. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other volcanic gases are hydrogen sulfide, hydrochloric acid, hydrogen, carbon monoxide, hydrofluoric acid, and other trace gases and volatile metals. The concentrations of these gas species can vary considerably from one volcano to the next.

  4. Monogenetic volcanic hazards and assessment

    Science.gov (United States)

    Connor, C.; Connor, L. J.; Richardson, J. A.

    2012-12-01

    Many of the Earth's major cities are build on the products of monogenetic volcanic eruptions and within geologically active basaltic volcanic fields. These cities include Mexico City (Mexico), Auckland (New Zealand), Melbourne (Australia), and Portland (USA) to name a few. Volcanic hazards in these areas are complex, and involve the potential formation of new volcanic vents and associated hazards, such as lava flows, tephra fallout, and ballistic hazards. Hazard assessment is complicated by the low recurrence rate of volcanism in most volcanic fields. We have developed a two-stage process for probabilistic modeling monogenetic volcanic hazards. The first step is an estimation of the possible locations of future eruptive vents based on kernel density estimation and recurrence rate of volcanism using Monte Carlo simulation and accounting for uncertainties in age determinations. The second step is convolution of this spatial density / recurrence rate model with hazard codes for modeling lava inundation, tephra fallout, and ballistic impacts. A methodology is presented using this two-stage approach to estimate lava flow hazard in several monogenetic volcanic fields, including at a nuclear power plant site near the Shamiram Plateau, a Quaternary volcanic field in Armenia. The location of possible future vents is determined by estimating spatial density from a distribution of 18 mapped vents using a 2-D elliptical Gaussian kernel function. The SAMSE method, a modified asymptotic mean squared error approach, uses the distribution of known eruptive vents to optimally determine a smoothing bandwidth for the Gaussian kernel function. The result is a probability map of vent density. A large random sample (N=10000) of vent locations is drawn from this probability map. For each randomly sampled vent location, a lava flow inundation model is executed. Lava flow input parameters (volume and average thickness) are determined from distributions fit to field observations of the low

  5. The Virtual Arizona Experience

    Science.gov (United States)

    Allison, M. L.; Davis, R.; Conway, F. M.; Bellasai, R.

    2012-12-01

    To commemorate the once-in-a-lifetime event of Arizona's hundredth birthday, the Centennial Commission and the Governor of Arizona envisioned a museum and companion website that would capture the state's history, celebrate its people, and embrace its future. Working with world-renowned museum designers, the state began to seek ideas from across Arizona to create plans for a journey of discovery through science and the humanities. The museum would introduce visitors to some of the people who nurtured the state through its early years and others who are innovating its tomorrows. Showcases would include the resources and experiences that shaped the state's history and are transforming its present day, highlighting the ingenuity that tamed the wild frontier and is envisioning Arizona's next frontiers through science and technology. The Arizona Experience (www.arizonaexperience.org) was initially intended to serve as the web presence for the physical museum, but as delays occurred with the physical museum, the site has quickly developed an identify of its own as an interactive, multimedia experience, reaching a wider audience with functions that would be difficult or expensive to produce in a museum. As leaders in scientific and technological innovation in the state, the Arizona Geological Survey was tasked with designing and creating the Arizona Experience site. The general themes remain the same; however, the site has added content and applications that are better suited to the online environment in order to create a rich, dynamic supplement to a physical museum experience. The website offers the features and displays of the future museum with the interactive nature and learning environment of the web. This provides an encyclopedic overview of the State of Arizona by subject matter experts in a manner that is free and open to the public and erases socio-economic, political, and physical boundaries. Over the Centennial Year of 2012 the site will release a new theme and

  6. Development of a geothermal resource in a fractured volcanic formation: Case study of the Sumikawa Geothermal Field, Japan. Final report, May 1, 1995--November 30, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Garg, S.K.; Combs, J.; Pritchett, J.W. [and others

    1997-07-01

    The principal purpose of this case study of the Sumikawa Geothermal Field is to document and to evaluate the use of drilling logs, surface and downhole geophysical measurements, chemical analyses and pressure transient data for the assessment of a high temperature volcanic geothermal field. This comprehensive report describes the work accomplished during FY 1993-1996. A brief review of the geological and geophysical surveys at the Sumikawa Geothermal Field is presented (Section 2). Chemical data, consisting of analyses of steam and water from Sumikawa wells, are described and interpreted to indicate compositions and temperatures of reservoir fluids (Section 3). The drilling information and downhole pressure, temperature and spinner surveys are used to determine feedzone locations, pressures and temperatures (Section 4). Available injection and production data from both slim holes and large-diameter wells are analyzed to evaluate injectivity/productivity indices and to investigate the variation of discharge rate with borehole diameter (Section 5). New interpretations of pressure transient data from several wells are discussed (Section 6). The available data have been synthesized to formulate a conceptual model for the Sumikawa Geothermal Field (Section 7).

  7. Northern Arizona Volcanoes

    Science.gov (United States)

    2006-01-01

    Northern Arizona is best known for the Grand Canyon. Less widely known are the hundreds of geologically young volcanoes, at least one of which buried the homes of local residents. San Francisco Mtn., a truncated stratovolcano at 3887 meters, was once a much taller structure (about 4900 meters) before it exploded some 400,000 years ago a la Mt. St. Helens. The young cinder cone field to its east includes Sunset Crater, that erupted in 1064 and buried Native American homes. This ASTER perspective was created by draping ASTER image data over topographic data from the U.S. Geological Survey National Elevation Data. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate. Size: 20.4 by 24.6 kilometers (12.6 by 15.2 miles) Location: 35.3 degrees North latitude, 111.5 degrees West longitude

  8. Volcanic Catastrophes

    Science.gov (United States)

    Eichelberger, J. C.

    2003-12-01

    The big news from 20th century geophysics may not be plate tectonics but rather the surprise return of catastrophism, following its apparent 19th century defeat to uniformitarianism. Divine miracles and plagues had yielded to the logic of integrating observations of everyday change over time. Yet the brilliant interpretation of the Cretaceous-Tertiary Boundary iridium anomaly introduced an empirically based catastrophism. Undoubtedly, decades of contemplating our own nuclear self-destruction played a role in this. Concepts of nuclear winter, volcanic winter, and meteor impact winter are closely allied. And once the veil of threat of all-out nuclear exchange began to lift, we could begin to imagine slower routes to destruction as "global change". As a way to end our world, fire is a good one. Three-dimensional magma chambers do not have as severe a magnitude limitation as essentially two-dimensional faults. Thus, while we have experienced earthquakes that are as big as they get, we have not experienced volcanic eruptions nearly as great as those preserved in the geologic record. The range extends to events almost three orders of magnitude greater than any eruptions of the 20th century. Such a calamity now would at the very least bring society to a temporary halt globally, and cause death and destruction on a continental scale. At maximum, there is the possibility of hindering photosynthesis and threatening life more generally. It has even been speculated that the relative genetic homogeneity of humankind derives from an evolutionary "bottleneck" from near-extinction in a volcanic cataclysm. This is somewhat more palatable to contemplate than a return to a form of Original Sin, in which we arrived at homogeneity by a sort of "ethnic cleansing". Lacking a written record of truly great eruptions, our sense of human impact must necessarily be aided by archeological and anthropological investigations. For example, there is much to be learned about the influence of

  9. Regional volcanic and structural study of Los Humeros, Puebla, Mexico geothermal field; Estudio regional volcanico y estructural del campo geotermico de Los Humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Hernandez, Aida [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)

    1995-01-01

    A regional volcanic and structural study focused to know the principal deformation phases and their effects in the reservoir rocks was conducted around the Los Humeros geothermal zone in Puebla, Mexico. Four stages of deformations were recognized. The oldest phase had a compressional character and acted in late Cretaceous. During Miocene and Pliocene two extensional phases affected the lithologic sequence. The youngest stage was produced by vertical deformation associated with the magmatic and hydrothermal activity of this Quaternary volcanic center. In the geothermal field zone, the fluid movements are limited by the low permeability. Although the last local deformation phase, which is probably still active, generated a reduced sector of relatively high permeability. [Espanol] Se presentan los resultados de un estudio estructural y volcanico regional que incluye la Caldera de Los Humeros, Puebla, Mexico realizado con el proposito de determinar las diferentes etapas de deformacion que la afectan, su origen, y los efectos causados en las unidades litologicas. Los resultados indican la presencia de 4 etapas de deformacion. La mas antigua, de fines del Cretacico, fue compresional y afecto la secuencia sedimentaria jurasico-cretacica. Posteriormente, en las rocas del Mioceno y Plioceno se identificaron dos etapas de deformacion regional de tipo extensional. La cuarta etapa fue de caracter local, afecto al centro volcanido de Los Humeros y se debe al empuje principalmente vertical, a sociado a fenomenos magnaticos e hidrotermales que acompanaron la actividad eruptiva de este centro. En la zona del campo geotermico el movimiento de fluidos es muy reducido debido a la baja permeabilidad global de las rocas donde se aloja el yacimiento. Sin embargo, la ultima etapa de deformacion local, que aun es activa, produjo un ligero incremento de la permeabilidad en zonas preferenciales, que actualmente controlan el movimiento de los fluidos.

  10. Rapid pre-eruptive thermal rejuvenation in a large silicic magma body: the case of the Masonic Park Tuff, Southern Rocky Mountain volcanic field, CO, USA

    Science.gov (United States)

    Sliwinski, J. T.; Bachmann, O.; Dungan, M. A.; Huber, C.; Deering, C. D.; Lipman, P. W.; Martin, L. H. J.; Liebske, C.

    2017-05-01

    Determining the mechanisms involved in generating large-volume eruptions (>100 km3) of silicic magma with crystallinities approaching rheological lock-up ( 50 vol% crystals) remains a challenge for volcanologists. The Cenozoic Southern Rocky Mountain volcanic field, in Colorado and northernmost New Mexico, USA, produced ten such crystal-rich ignimbrites within 3 m.y. This work focuses on the 28.7 Ma Masonic Park Tuff, a dacitic ( 62-65 wt% SiO2) ignimbrite with an estimated erupted volume of 500 km3 and an average of 45 vol% crystals. Near-absence of quartz, titanite, and sanidine, pronounced An-rich spikes near the rims of plagioclase, and reverse zoning in clinopyroxene record the reheating (from 750 to >800 °C) of an upper crustal mush in response to hotter recharge from below. Zircon U-Pb ages suggest prolonged magmatic residence, while Yb/Dy vs temperature trends indicate co-crystallization with titanite which was later resorbed. High Sr, Ba, and Ti concentrations in plagioclase microlites and phenocryst rims require in-situ feldspar melting and concurrent, but limited, mass addition provided by the recharge, likely in the form of a melt-gas mixture. The larger Fish Canyon Tuff, which erupted from the same location 0.7 m.y. later, also underwent pre-eruptive reheating and partial melting of quartz, titanite, and feldspars in a long-lived upper crustal mush following the underplating of hotter magma. The Fish Canyon Tuff, however, records cooler pre-eruptive temperatures ( 710-760 °C) and a mineral assemblage indicative of higher magmatic water contents (abundant resorbed sanidine and quartz, euhedral amphibole and titanite, and absence of pyroxene). These similar pre-eruptive mush-reactivation histories, despite differing mineral assemblages and pre-eruptive temperatures, indicate that thermal rejuvenation is a key step in the eruption of crystal-rich silicic volcanics over a wide range of conditions.

  11. Arizona motor vehicle crash facts, 2010

    Science.gov (United States)

    2010-08-22

    This publication is an annual statistical review of the motor vehicle crashes in the State of Arizona for the calendar year 2010. The results are compiled from Arizona Traffic Accident Reports submitted to the Arizona Department of Transportation by ...

  12. Arizona motor vehicle crash facts, 2008

    Science.gov (United States)

    2009-06-25

    This publication is an annual statistical review of the motor vehicle crashes in the State of Arizona for the calendar year 2008. : The results are compiled from Arizona Traffic Accident Reports submitted to the Arizona Department of Transportation b...

  13. Arizona motor vehicle crash facts, 2007

    Science.gov (United States)

    2009-02-17

    This publication is an annual statistical review of the motor vehicle crashes in the State of Arizona for the calendar year 2007. : The results are compiled from Arizona Traffic Accident Reports submitted to the Arizona Department of Transportation b...

  14. Arizona motor vehicle crash facts, 2014.

    Science.gov (United States)

    2015-06-01

    This publication is an annual statistical review of the motor vehicle crashes in the State of Arizona for the calendar year 2014. The : results are compiled from Arizona Traffic Accident Reports submitted to the Arizona Department of Transportation b...

  15. Arizona motor vehicle crash facts, 2009

    Science.gov (United States)

    2009-09-29

    This publication is a statistical review of the motor vehicle crashes in the State of Arizona for calendar year 2009. The results are compiled from Arizona Traffic Accident Reports submitted to the Arizona Department of Transportation by state, count...

  16. Kaljujooniste keskus Arizonas / Andres Kurg

    Index Scriptorium Estoniae

    Kurg, Andres, 1975-

    1998-01-01

    Arhitekt William Bruderi projekteeritud kaljujooniste uurimis- ja eksponeerimiskeskus Phoenixis, Arizonas säilitab kivijooniseid, mille autoriteks olid sealset piirkonda kuni 16. sajandini asustanud hohokamid

  17. The petrologic history of the Sanganguey volcanic field, Nayarit, Mexico: Comparisons in a suite of crystal-rich and crystal-poor lavas

    Science.gov (United States)

    Crabtree, Stephen M.; Waters, Laura E.

    2017-04-01

    To evaluate if intermediate magmas erupting from Volcán Sanganguey (Mexico) and the surrounding volcanic field are formed by mixing of basalts and rhyolites or if they initially exist as intermediate liquids, a detailed petrological study is presented for eight andesite and dacite magmas. Six of the samples erupted from the central edifice (four andesites and two dacites) are crystal-rich (≤ 50 vol%), whereas the remaining two samples (one andesite and one dacite) erupted from monogenetic vents in the peripheral volcanic field and are crystal poor (≤ 5 vol%). Despite the variation in crystallinity, all samples are multiply saturated in five to seven mineral phases (plagioclase + orthopyroxene + titanomagnetite + ilmenite + apatite ± clinopyroxene ± hornblende). In all samples, plagioclase spans a 30-40 mol% An range in composition and orthopyroxene spans a range in Mg# of 5-10. Pre-eruptive temperatures and oxygen fugacites (relative to the NNO buffer) range from 853 (± 24) to 1085 (± 16) °C and - 0.1 (± 0.1) to 0.9 (± 0.1) ∆ NNO, on the basis of Fe-Ti two oxide thermometry. Application of the plagioclase-liquid hygrometer to the samples reveals maximum H2O contents that range from 1.7-6.2 wt%. Comparison with phase equilibrium experiments demonstrates that all plagioclase and orthopyroxene compositions in the crystal-poor samples could have grown from their respective whole rock compositions. Comparison of crystal rich samples with phase equilibrium experiments reveals the presence of sodic xenocrysts which reflect resorption textures and an estimated excess plagioclase crystal cargo of > 6 vol%. The excess plagioclase crystal cargo is not distinguishable from phenocrystic plagioclase based on composition or texture, suggesting that they were also grown in intermediate melts, and are therefore described as antecrystic. No calcic plagioclase xenocrysts (> An79) typical of hydrous arc basalts are observed, thus it is likely that the excess plagioclase

  18. The visibility of airborne volcanic ash from the flight deck of an aircraft - The effect of clouds in the field of view

    Science.gov (United States)

    Sauer, Daniel; Gasteiger, Josef; Emde, Claudia; Buras, Robert; Mayer, Bernhard; Weinzierl, Bernadett

    2013-05-01

    In April 2010, the volcanic ash cloud from the Eyjafjalla volcano in Iceland strongly impacted aviation in Europe. Several other incidents in the past have shown that volcanic ash can have severe consequences on aviation. One operational necessity is, therefore, to determine whether a pilot has the means to avoid flying through potentially dangerous volcanic ash just by visual observation of the sky from the cockpit of an aircraft. Here we investigate how clouds affect the visibility of a volcanic ash aerosol layer for an observer in the cockpit of an aircraft using a 3D Monte Carlo radiative transfer model MYSTIC. This study builds on the results of a previous study on the visibility of airborne volcanic ash in Weinzierl et al. (2012) where we considered the cloud-free case. With clouds, the discernibility of ash layers is substantially reduced. Even layers with comparably high mass concentrations of 2 mg m-3 might not be visible for uninformed observers.

  19. Arizona Conserve Water Educators Guide

    Science.gov (United States)

    Project WET Foundation, 2007

    2007-01-01

    This award-winning, 350-page, full-color book provides a thorough study of Arizona water resources from a water conservation perspective. Its background section contains maps, graphs, diagrams and photos that facilitate the teaching of 15 interactive, multi-disciplinary lessons to K-12 students. In addition, 10 Arizona case studies are highlighted…

  20. Oxygen isotope evolution of the Lake Owyhee volcanic field, Oregon, and implications for low-δ18O magmas of the Snake River Plain - Yellowstone hotspot

    Science.gov (United States)

    Blum, T.; Kitajima, K.; Nakashima, D.; Valley, J. W.

    2013-12-01

    The Snake River Plain - Yellowstone (SRP-Y) hotspot trend is one of the largest known low-δ18O magmatic provinces, yet the timing and distribution of hydrothermal alteration relative to hotspot magmatism remains incompletely understood. Existing models for SRP-Y low-δ18O magma genesis differ regarding the timing of protolith alteration (e.g. Eocene vs. present), depth at which alteration occurs (e.g. 15 km vs. caldera collapse, crustal scale fluid flow, etc.). We expand the existing oxygen isotope data set for zircon in the Lake Owyhee volcanic field (LOVF) of east central Oregon to further identify magmatic oxygen isotope trends within the field. These data offer insight into the timing of alteration and the extent of the greater SRP-Y low-δ18O province, as well as the conditions that generate large low-δ18O provinces. 16-14 Ma silicic volcanism in the LOVF is linked to the pre-14 Ma SRP-Y hotspot, with volcanism partially overlapping extension in the north-south trending Oregon-Idaho Graben (OIG). Ion microprobe analyses of zircons from 16 LOVF silicic lavas and tuffs reveal homogeneous zircons on both the single grain and hand sample scales: individual samples have 2 S.D. for δ18O ranging from 0.27 to 0.96‰ (SMOW), and sample averages ranging from 1.8 to 6.0‰, excluding texturally chaotic and/or porous zircons which have δ18O values as low as 0.0‰. All low-δ18O LOVF magmas, including the caldera-forming Tuff of Leslie Gulch and Tuff of Spring Creek, are confined to the OIG, although not all zircons from within the OIG have low δ18O values. The presence and sequence of low-δ18O magmas in the LOVF and adjacent central Snake River Plain (CSRP) cannot be explained by existing caldera subsidence or pre-hotspot source models. These data, however, combined with volumetrically limited low-δ18O material in the adjacent Idaho Batholith and Basin and Range, are consistent with low-δ18O magmas generated by the superposition of high hotspot-derived thermal

  1. Mechanical interaction between volcanic systems in Libya

    Science.gov (United States)

    Elshaafi, Abdelsalam; Gudmundsson, Agust

    2018-01-01

    The spatial distributions of monogenetic volcanoes, primarily volcanic craters, within the four principal volcanic provinces of Libya are examined and presented on a volcano-density map. Six main volcanic clusters have been identified, referred to as volcanic systems. Remarkably, the Al Haruj (AHVP) and Nuqay (NVP) volcanic provinces have double-peak volcano-density distributions, while the Gharyan (GVP) and As Sawda (SVP) volcanic provinces have single-peak volcano-density distributions. We interpret each volcano-density peak as corresponding to a separate volcanic system, so that there is a total of six systems in these four provinces. There was an overlap in volcanic activity in these provinces with at least three simultaneously active. We propose that each of the 6 volcanic systems was/is supplied with magma from a large sill-like reservoir - similar in lateral dimensions to the systems/clusters themselves. Numerical results show zones of high tensile and shear stresses between the reservoirs that coincide roughly with the main swarms of extension (dykes and volcanic fissures) and shear (faults) fractures in the areas. The most recent volcanic eruptions in Libya fall within the modelled high-stress concentration zones, primarily eruptions in the volcano Waw an Namus and the Holocene Al Mashaqaq lava flow. There are no known eruptions in Libya in historical time, but some or all the volcanic systems may have had one or more arrested historical dyke injections. In particular, part of the recurrent seismic events in the Hun Graben in the northwest Libya may be related to dyke propagation and arrest. If some of the inferred magma reservoirs are still fluid, as is likely, they pose earthquake and volcanic hazards to parts of Libya, particularly to the city of Gharyan and Zallah town, as well as to many oil-field operations.

  2. A new genetic interpretation for the Caotaobei uranium deposit associated with the shoshonitic volcanic rocks in the Hecaokeng ore field, southern Jiangxi, China

    Directory of Open Access Journals (Sweden)

    Dong-Sheng Yang

    2017-03-01

    Full Text Available Combined with in-situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS zircon UPb geochronology, published and unpublished literature on the Caotaobei uranium deposit in southern Jiangxi province, China, is re-examined to provide an improved understanding of the origin of the main ore (103 Ma. The Caotaobei deposit lies in the Hecaokeng ore field and is currently one of China's largest, volcanic-related uranium producers. Unlike commonly known volcanogenic uranium deposits throughout the world, it is spatially associated with intermediate lavas with a shoshonitic composition. Uranium mineralization (pitchblende occurs predominantly as veinlets, disseminations, and massive ores, hosted by the cryptoexplosive breccias rimming the Caotaobei crater. Zircons from one latite define four distinct 206Pb/238U age groups at 220–235 Ma (Triassic, 188 Ma (Early Jurassic, 131–137 Ma (Early Cretaceous, and 97–103 Ma (Early-Late Cretaceous transition, hereafter termed mid-Cretaceous. The integrated age (134 ± 2 Ma of Early Cretaceous zircons (group III is interpreted as representing the time of lava emplacement. The age data, together with the re-examination of literature, does not definitively support a volcanogenic origin for the generation of the deposit, which was proposed by the previous workers based mainly on the close spatial relationship and the age similarity between the main ore and volcanic lavas. Drill core and grade-control data reveal that rich concentrations of primary uranium ore are common around the granite porphyry dikes cutting the lavas, and that the cryptoexplosive breccias away from the dikes are barren or unmineralized. These observations indicate that the emplacement of the granite porphyries exerts a fundamental control on ore distribution and thus a genetic link exists between main-stage uranium mineralization and the intrusions of the dikes. Zircon overgrowths of mid-Cretaceous age (99.6

  3. Chlorine as a geobarometer tool: Application to the explosive eruptions of the Volcanic Campanian District (Mount Somma-Vesuvius, Phlegrean Fields, Ischia)

    Science.gov (United States)

    Balcone-Boissard, Hélène; Boudon, Georges; Zdanowicz, Géraldine; Orsi, Giovanni; Civetta, Lucia; Webster, Jim D.; Cioni, Raffaello; D'Antonio, Massimo

    2016-04-01

    One of the current stakes in modern volcanology is the definition of magma storage conditions which has direct implications on the eruptive style and thus on the associated risks and the management of likely related crisis. In alkaline differentiated magmas, chlorine (Cl), contrary to H2O, occurs as a minor volatile species but may be used as a geobarometer. Numerous experimental studies on Cl solubility have highlighted its saturation conditions in silicate melts. The NaCl-H2O system is characterized by immiscibility under wide ranges of pressure, temperature and NaCl content (Somma-Vesuvius, Phlegrean Fields and Ischia. We have analysed the products of the representative explosive eruptions of each volcano, including Plinian, sub-Plinian and strombolian events. We have focussed our research on the earliest emitted, most evolved products of each eruption, likely representing the shallower, fluid-saturated portion of the reservoir. As the studied eruptions cover the entire eruptive history of each volcanic system, the results allow better constraining the evolution through time of the shallow plumbing system. We highlighted for Mount Somma - Vesuvius two magma ponding zones, at ~170-200 MPa and ~105-115 MPa, alternatively active in time. For Phlegrean Fields, we evidence a progressive deepening of the shallow reservoirs, from the Campanian Ignimbrite (30-50 MPa) to the Monte Nuovo eruption (115 MPa). Only one eruption was studied for Ischia, the Cretaio eruption, that shows a reservoir at 140 MPa. The results on pressure are in large agreement with literature. The Cl geobarometer may help scientists to define the reservoir dynamics through time and provide strong constraints on pre-eruptive conditions, of utmost importance for the interpretation of the monitoring data and the identification of precursory signals.

  4. State-space approach to evaluate spatial variability of field measured soil water status along a line transect in a volcanic-vesuvian soil

    Directory of Open Access Journals (Sweden)

    A. Comegna

    2010-12-01

    Full Text Available Unsaturated hydraulic properties and their spatial variability today are analyzed in order to use properly mathematical models developed to simulate flow of the water and solute movement at the field-scale soils. Many studies have shown that observations of soil hydraulic properties should not be considered purely random, given that they possess a structure which may be described by means of stochastic processes. The techniques used for analyzing such a structure have essentially been based either on the theory of regionalized variables or to a lesser extent, on the analysis of time series. This work attempts to use the time-series approach mentioned above by means of a study of pressure head h and water content θ which characterize soil water status, in the space-time domain. The data of the analyses were recorded in the open field during a controlled drainage process, evaporation being prevented, along a 50 m transect in a volcanic Vesuvian soil. The isotropic hypothesis is empirical proved and then the autocorrelation ACF and the partial autocorrelation functions PACF were used to identify and estimate the ARMA(1,1 statistical model for the analyzed series and the AR(1 for the extracted signal. Relations with a state-space model are investigated, and a bivariate AR(1 model fitted. The simultaneous relations between θ and h are considered and estimated. The results are of value for sampling strategies and they should incite to a larger use of time and space series analysis.

  5. Volcan Reventador's Unusual Umbrella

    Science.gov (United States)

    Chakraborty, P.; Gioia, G.; Kieffer, S. W.

    2005-12-01

    In the past two decades, field observations of the deposits of volcanoes have been supplemented by systemmatic, and sometimes, opportunistic photographic documentation. Two photographs of the umbrella of the December 3, 2002 eruption of Volcan Reventador, Ecuador, reveal a prominently scalloped umbrella that is unlike any umbrella previously documented on a volcanic column. The material in the umbrella was being swept off a descending pyroclastic flow, and was, therefore, a co-ignimbrite cloud. We propose that the scallops are the result of a turbulent Rayleigh-Taylor (RT) instability with no precedents in volcanology. We ascribe the rare loss of buoyancy that drives this instability to the fact that the Reventador column fed on a cool co-ignimbrite cloud. On the basis of the observed wavelength of the scallops, we estimate a value for the eddy viscosity of the umbrella of 4000 ~m2/s. This value is consistent with a previously obtained lower bound (200 ~m2/s, K. Wohletz, priv. comm., 2005). We do not know the fate of the material in the umbrella subsequent to the photos. The analysis suggests that the umbrella was negatively buoyant. Field work on the co-ignimbrite deposits might reveal whether or not the material reimpacted, and if so, where and whether or not this material was involved in the hazardous flows that affected the main oil pipeline across Ecuador.

  6. Expanding Geophysical and Geochemical Investigation of Causes of Extraordinary Unrest at the Laguna del Maule (Rhyolitic) Volcanic Field, Southern Andes, Chile

    Science.gov (United States)

    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 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 mixing events prior to the current unrest. The overall aim is to integrate these observations and to construct numerical models of system dynamics. We are developing communications protocols and a web site to facilitate sharing of findings among the team members and with the public.

  7. Geochemical and zircon isotopic evidence for extensive high level crustal contamination in Miocene to mid-Pleistocene intra-plate volcanic rocks from the Tengchong field, western Yunnan, China

    Science.gov (United States)

    Li, Linlin; Shi, Yuruo; Williams, Ian S.; Anderson, J. Lawford; Wu, Zhonghai; Wang, Shubing

    2017-08-01

    SHRIMP zircon Pb/U dating of Cenozoic volcanic rocks in the Tengchong area, western Yunnan Province, China, shows that the dacite and andesitic breccia lavas from Qushi village were intruded at 480 ± 10 ka and 800 ± 40 ka, respectively. Moreover, Pb/U dating of trachyandesite from Tuantian village and olivine basalt from Wuhe village give weighted mean 206Pb/238U ages of 2.82 ± 0.08 Ma and 12.28 ± 0.30 Ma. Corrections for initial 230Th disequilibrium of zircon were used for the former two younger ages. The Tengchong volcanic rocks have a large range of SiO2 (48.6-66.9 wt.%) and mostly belong to a high-K calc-alkaline series. The lavas originated from heterogeneous sources and were modified by subsequent fractional crystallization. The REE and other trace element patterns of the Tengchong volcanic rocks resemble magmas having a large component of continental crust. All have similar degrees of LREE and HREE fractionation and are enriched in LILE, La, Ce and Pb, with depletions in Nb, Ta, Ti, Sr and P relative to primitive mantle. Zircon δ18O values of 6.96 ± 0.17 and 7.01 ± 0.24‰ and highly varied negative εHf(t) values of - 1.5 to - 11.0 and - 10.3 to - 13.7, as well as the presence of inherited zircon grains in the studied samples, indicate that the magmas contain crustal material on a large scale. The Tengchong volcanic rocks have HFSE ratios (e.g., Nb/Ta, La/Nb, Zr/Y) similar to continental flood basalts, indicative of an intra-plate extensional tectonic setting. Widespread distributed faults might have facilitated upwelling of mantle-derived melts and eruptions from shallow crustal magma chambers to form the large volcanic field.

  8. Comparison of ASTER- and AVIRIS-Derived Mineraland Vegetation Maps of the White Horse Replacement Alunite Deposit and Surrounding Area, Marysvale Volcanic Field, Utah

    Science.gov (United States)

    Rockwell, Barnaby W.

    2009-01-01

    This report presents and compares mineral and vegetation maps of parts of the Marysvale volcanic field in west-central Utah that were published in a recent paper describing the White Horse replacement alunite deposit. Detailed, field-verified maps of the deposit were produced from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data acquired from a low-altitude Twin Otter turboprop airborne platform. Reconnaissance-level maps of surrounding areas including the central and northern Tushar Mountains, Pahvant Range, and portions of the Sevier Plateau to the east were produced from visible, near-infrared, and shortwave-infrared data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor carried aboard the Terra satellite platform. These maps are also compared to a previously published mineral map of the same area generated from AVIRIS data acquired from the high-altitude NASA ER-2 jet platform. All of the maps were generated by similar analysis methods, enabling the direct comparison of the spatial scale and mineral composition of surface geologic features that can be identified using the three types of remote sensing data. The high spatial (2-17 meter) and spectral (224 bands) resolution AVIRIS data can be used to generate detailed mineral and vegetation maps suitable for geologic and geoenvironmental studies of individual deposits, mines, and smelters. The lower spatial (15-30 meter) and spectral (9 bands) resolution ASTER data are better suited to less detailed mineralogical studies of lithology and alteration across entire hydrothermal systems and mining districts, including regional mineral resource and geoenvironmental assessments. The results presented here demonstrate that minerals and mineral mixtures can be directly identified using AVIRIS and ASTER data to elucidate spatial patterns of mineralogic zonation; AVIRIS data can enable the generation of maps with significantly greater detail and accuracy. The

  9. Measurement of airborne particle concentrations near the Sunset Crater volcano, Arizona.

    Science.gov (United States)

    Benke, Roland R; Hooper, Donald M; Durham, James S; Bannon, Donald R; Compton, Keith L; Necsoiu, Marius; McGinnis, Ronald N

    2009-02-01

    Direct measurements of airborne particle mass concentrations or mass loads are often used to estimate health effects from the inhalation of resuspended contaminated soil. Airborne particle mass concentrations were measured using a personal sampler under a variety of surface-disturbing activities within different depositional environments at both volcanic and nonvolcanic sites near the Sunset Crater volcano in northern Arizona. Focused field investigations were performed at this analog site to improve the understanding of natural and human-induced processes at Yucca Mountain, Nevada. The level of surface-disturbing activity was found to be the most influential factor affecting the measured airborne particle concentrations, which increased over three orders of magnitude relative to ambient conditions. As the surface-disturbing activity level increased, the particle size distribution and the majority of airborne particle mass shifted from particles with aerodynamic diameters less than 10 mum (0.00039 in) to particles with aerodynamic diameters greater than 10 mum (0.00039 in). Under ambient conditions, above average wind speeds tended to increase airborne particle concentrations. In contrast, stronger winds tended to decrease airborne particle concentrations in the breathing zone during light and heavy surface-disturbing conditions. A slight increase in the average airborne particle concentration during ambient conditions was found above older nonvolcanic deposits, which tended to be finer grained than the Sunset Crater tephra deposits. An increased airborne particle concentration was realized when walking on an extremely fine-grained deposit, but the sensitivity of airborne particle concentrations to the resuspendible fraction of near-surface grain mass was not conclusive in the field setting when human activities disturbed the bulk of near-surface material. Although the limited sample size precluded detailed statistical analysis, the differences in airborne particle

  10. Paleoproterozoic (~1.88Ga felsic volcanism of the Iricoumé Group in the Pitinga Mining District area, Amazonian Craton, Brazil: insights in ancient volcanic processes from field and petrologic data

    Directory of Open Access Journals (Sweden)

    Ronaldo Pierosan

    2011-09-01

    Full Text Available The Iricoumé Group correspond to the most expressive Paleoproterozoic volcanism in the Guyana Shield, Amazonian craton. The volcanics are coeval with Mapuera granitoids, and belong to the Uatumã magmatism. They have U-Pb ages around 1880 Ma, and geochemical signatures of α-type magmas. Iricoumé volcanics consist of porphyritic trachyte to rhyolite, associated to crystal-rich ignimbrites and co-ignimbritic fall tuffs and surges. The amount and morphology of phenocrysts can be useful to distinguish lava (flow and dome from hypabyssal units. The morphology of ignimbrite crystals allows the distinction between effusive units and ignimbrite, when pyroclasts are obliterated. Co-ignimbritic tuffs are massive, and some show stratifications that suggest deposition by current traction flow. Zircon and apatite saturation temperatures vary from 799°C to 980°C, are in agreement with most temperatures of α-type melts and can be interpreted as minimum liquidus temperature. The viscosities estimation for rhyolitic and trachytic compositions yield values close to experimentally determined melts, and show a typical exponential decay with water addition. The emplacement of Iricoumé volcanics and part of Mapuera granitoids was controlled by ring-faults in an intracratonic environment. A genesis related to the caldera complex setting can be assumed for the Iricoumé-Mapuera volcano-plutonic association in the Pitinga Mining District.O Grupo Iricoumé corresponde ao mais expressivo vulcanismo Paleoproterozóico do Escudo das Guianas, craton Amazônico. As rochas vulcânicas são coexistentes com os granitóides Mapuera, e pertencem ao magmatismo Uatumã. Possuem idades U-Pb em torno 1888 Ma, e assinaturas geoquímicas de magmas tipo-A. As vulcânicas do Iricoumé consistem de traquitos a riolitos porfiríticos, associados a ignimbritos ricos em cristal e tufos co-ignimbríticos de queda e surge. A quantidade e a morfologia dos fenocristais podem ser

  11. Geologic Map of Wupatki National Monument and Vicinity, Coconino County, Northern Arizona

    Science.gov (United States)

    Billingsley, George H.; Priest, Susan S.; Felger, Tracey J.

    2007-01-01

    Introduction The geologic map of Wupatki National Monument is a cooperative effort between the U.S. Geological Survey, the National Park Service, and the Navajo Nation to provide geologic information for resource management officials of the National Park Service, U.S. Forest Service, Navajo Indian Reservation (herein the Navajo Nation), and visitor information services at Wupatki National Monument, Arizona. Funding for the map was provided in part by the Water Rights Branch of the Water Resources Division of the National Park Service. Field work on the Navajo Nation was conducted under a permit from the Navajo Nation Minerals Department. Any persons wishing to conduct geologic investigations on the Navajo Nation must first apply for, and receive, a permit from the Navajo Nation Minerals Department, P.O. Box 1910, Window Rock, Arizona 86515, telephone (928)-871-6587. Wupatki National Monument lies within the USGS 1:24,000-scale Wupatki NE, Wupatki SE, Wupatki SW, Gray Mountain, East of SP Mountain, and Campbell Francis Wash quadrangles in northern Arizona. The map is bounded approximately by longitudes 111? 16' to 111? 32' 30' W. and latitudes 35? 30' to 35? 37' 40' N. The map area is in Coconino County on the southern part of the Colorado Plateaus geologic province (herein Colorado Plateau). The map area is locally subdivided into three physiographic parts, the Coconino Plateau, the Little Colorado River Valley, and the San Francisco Volcanic Field as defined by Billingsley and others (1997) [fig. 1]. Elevations range from 4,220 ft (1,286 m) at the Little Colorado River near the northeast corner of the map area to about 6,100 ft (1,859 m) at the southwest corner of the map area. The small community of Gray Mountain is about 16 mi (26 km) northwest of Wupatki National Monument Visitor Center, and Flagstaff, Arizona, the nearest metropolitan area, is about 24 mi (38 km) southwest of the Visitor Center (fig. 1). U.S. Highway 89 provides access to the west entrance of

  12. Mantle Transition Zone Derivation of Ultramafic Xenoliths in San Quintin Volcanic Field, Baja California: Evidence from Micro-Laser Raman Spectroscopic Study.

    Science.gov (United States)

    Basu, A. R.; Chakrabarty, P.

    2016-12-01

    Spinel lherzolite xenoliths from the Holocene San Quintin Volcanic field in Baja California are well-studied for their mineralogical, petrological and geochemical characteristics, including their micro-structural and seismic properties that collectively suggest complex multiple histories of plastic deformation, re-crystallization and melt-rock interactions in the upper mantle. The ultramafic xenoliths are remarkable for their strong deformation displaying granular, porphryoclastic, tabular mosaic and equigranular microstructures. We used a Thermo ScientificTM DXRTMxi Raman Imaging microscope with an Ar ion 532 nm wavelength laser to image the various mineral phases in olivines and orthopyroxenes of several of the xenoliths. Many of the samples show hematite-decorated dislocations in the large ( 2mm) olivine grains showing sub-grain boundaries. We confirmed the hematite in the dislocation structures by their Raman spectra. Most interestingly, the olivine grains show Raman shift at 823.3 cm-1 and 855.8 cm-1: often these doublets show inversion and a slight shift to the higher side with respect to forsteritic olivine, indicating high pressure Mg2SiO4 phase. The presence of both high pressure and normal olivine within a 30 mµ range of the olivine in a number of samples studied indicate derivation of the xenoliths from the mantle transition zone in an upward flow and decompression while the hematite precipitated along the dislocations in the olivine. In some of the orthopyroxene grains adjacent to these olivines, showing high pressure Mg2SiO4 and normal forsteritic olivine, the presence of clinoenstatite lamellae are also confirmed by Raman studies. In summary, we present in this study three lines of evidence including exsolution of Fe3+ - bearing hematite along dislocations in olivine, presence of high pressure Mg2SiO4 containing this hematite-decorated dislocations and finally the clinoenstatite lamellae in orthopyroxene, indicating that the mineralogy of the spinel

  13. Slab-derived metasomatism in the Carpathian-Pannonian mantle revealed by investigations of mantle xenoliths from the Bakony-Balaton Highland Volcanic Field

    Science.gov (United States)

    Créon, Laura; Delpech, Guillaume; Rouchon, Virgile; Guyot, François

    2017-08-01

    A suite of fifteen peridotite xenoliths from the Bakony-Balaton Highland Volcanic Field (BBHVF, Pannonian Basin, Central Europe) that show abundant petrographic evidence of fluid and melt percolation were studied in order to decipher the formation of their melt pockets and veins. The suite mainly consists of ;fertile; lherzolites (5.8-19.9 vol.% clinopyroxene) and a few harzburgites (1.9-5.4 vol.% clinopyroxene) from well-known localities (Szentbékkálla, Szigliget) and two previously unreported localities (Füzes-tó and Mindszentkálla). Major and trace element data indicate that most of the peridotites record variable degrees of partial melt extraction, up to > 15% for the harzburgites. Subsequently, the xenoliths experienced at least two stages of metasomatic modification. The first stage was associated with percolation of a volatile-bearing silicate melt and resulted in crystallization of amphibole, enrichment in the most incompatible trace elements (Ba, Th, U, Sr), and development of negative Nb-Ta anomalies in clinopyroxene. The second and last metasomatic event, widespread beneath the BBHVF, is associated with the formation of silicate melt pockets, physically connected to a network of melt veins, with large and abundant CO2 vesicles. The glass in these veins has sub-alkaline trachy-andesitic composition and displays an OIB-like trace element signature. Its composition attests to the migration through a supra-subduction zone mantle wedge of silicic melt highly enriched in volatiles (CO2, H2O, Cl, F), LILE, REE and HFSE and consistent with compositions of natural and experimental examples of slab melting-derived magma. In the present case, however, melt was likely derived from melting of oceanic crust and carbonated sediments under conditions where Nb-rich mineral phases were not stable in the residue. A likely scenario for the origin such melts involves melting after subduction ceased as the slab thermally equilibrated with the asthenosphere. Melt

  14. Geology and geochemistry of Pelagatos, Cerro del Agua, and Dos Cerros monogenetic volcanoes in the Sierra Chichinautzin Volcanic Field, south of México City

    Science.gov (United States)

    Agustín-Flores, Javier; Siebe, Claus; Guilbaud, Marie-Noëlle

    2011-04-01

    This study focuses on the geology and geochemistry of three closely-spaced monogenetic volcanoes that are located in the NE sector of the Sierra Chichinautzin Volcanic Field near México City. Pelagatos (3020 m.a.s.l.) is a small scoria cone (0.0017 km 3) with lava flows (0.036 km 3) that covered an area of 4.9 km 2. Cerro del Agua scoria cone (3480 m.a.s.l., 0.028 km 3) produced several lava flows (0.24 km 3) covering an area of 17.6 km 2. Dos Cerros is a lava shield which covers an area of 80.3 km 2 and is crowned by two scoria cones: Tezpomayo (3080 m.a.s.l., 0.022 km 3) and La Ninfa (3000 m.a.s.l., 0.032 km 3). The eruptions of Cerro del Agua and Pelagatos occurred between 2500 and 14,000 yr BP. The Dos Cerros eruption took place close to 14,000 yr BP as constrained by radiocarbon dating. Rocks from these three volcanoes are olivine-hypersthene normative basaltic andesites and andesites with porphyritic, aphanitic, and glomeroporphyritic textures. Their mineral assemblages include olivine, clinopyroxene, and orthopyroxene phenocrysts (≤ 10 vol.%) embedded in a trachytic groundmass which consists mainly of plagioclase microlites and glass. Pelagatos rocks also present quartz xenocrysts. Due to their high Cr and Ni contents, and high Mg#s, Pelagatos rocks are considered to be derived from primitive magmas, hence the importance of this volcano for understanding petrogenetic processes in this region. Major and trace element abundances and petrography of products from these volcanoes indicate a certain degree of crystal fractionation during ascent to the surface. However, the magmas that formed the volcanoes evolved independently from each other and are not cogenetically related. REE, HFSE, LILE, and isotopic (Sr, Nd, and Pb) compositions point towards a heterogeneous mantle source that has been metasomatized by aqueous/melt phases from the subducted Cocos slab. There is no clear evidence of important crustal contributions in the compositions of Pelagatos and

  15. Libraries in Arizona: MedlinePlus

    Science.gov (United States)

    ... this page: https://medlineplus.gov/libraries/arizona.html Libraries in Arizona To use the sharing features on ... Medical Center John B. Jamison, M.D. Memorial Library 1200 N. Beaver St. Flagstaff, AZ 86001 928- ...

  16. 75 FR 64681 - Pistachios Grown in California, Arizona, and New Mexico; Continuance Referendum

    Science.gov (United States)

    2010-10-20

    ..., Marketing Specialist, or Kurt J. Kimmel, Regional Manager, California Marketing Field Office, Marketing...; ] DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 983 Pistachios Grown in California, Arizona, and New Mexico; Continuance Referendum AGENCY: Agricultural Marketing Service, USDA. ACTION...

  17. SOURCE PHENOMENOLOGY EXPERIMENTS IN ARIZONA

    Energy Technology Data Exchange (ETDEWEB)

    Jessie L. Bonner; Brian Stump; Mark Leidig; Heather Hooper; Xiaoning (David) Yang; Rongmao Zhou; Tae Sung Kim; William R. Walter; Aaron Velasco; Chris Hayward; Diane Baker; C. L. Edwards; Steven Harder; Travis Glenn; Cleat Zeiler; James Britton; James F. Lewkowicz

    2005-09-30

    The Arizona Source Phenomenology Experiments (SPE) have resulted in an important dataset for the nuclear monitoring community. The 19 dedicated single-fired explosions and multiple delay-fired mining explosions were recorded by one of the most densely instrumented accelerometer and seismometer arrays ever fielded, and the data have already proven useful in quantifying confinement and excitation effects for the sources. It is very interesting to note that we have observed differences in the phenomenology of these two series of explosions resulting from the differences between the relatively slow (limestone) and fast (granodiorite) media. We observed differences at the two SPE sites in the way the rock failed during the explosions, how the S-waves were generated, and the amplitude behavior as a function of confinement. Our consortium's goal is to use the synergy of the multiple datasets collected during this experiment to unravel the phenomenological differences between the two emplacement media. The data suggest that the main difference between single-fired chemical and delay-fired mining explosion seismograms at regional distances is the increased surface wave energy for the latter source type. The effect of the delay-firing is to decrease the high-frequency P-wave amplitudes while increasing the surface wave energy because of the longer source duration and spall components. The results suggest that the single-fired explosions are surrogates for nuclear explosions in higher frequency bands (e.g., 6-8 Hz Pg/Lg discriminants). We have shown that the SPE shots, together with the mining explosions, are efficient sources of S-wave energy, and our next research stage is to postulate the possible sources contributing to the shear-wave energy.

  18. Flux and genesis of CO2 degassing from volcanic-geothermal fields of Gulu-Yadong rift in the Lhasa terrane, South Tibet: Constraints on characteristics of deep carbon cycle in the India-Asia continent subduction zone

    Science.gov (United States)

    Zhang, Lihong; Guo, Zhengfu; Sano, Yuji; Zhang, Maoliang; Sun, Yutao; Cheng, Zhihui; Yang, Tsanyao Frank

    2017-11-01

    Gulu-Yadong rift (GYR) is the longest extensional, NE-SW-trending rift in the Himalayas and Lhasa terrane of South Tibet. Many volcanic-geothermal fields (VGFs), which comprise intense hot springs, steaming fissures, geysers and soil micro-seepage, are distributed in the GYR, making it ideal area for studying deep carbon emissions in the India-Asia continent subduction zone. As for the northern segment of GYR in the Lhasa terrane, its total flux and genesis of CO2 emissions are poorly understood. Following accumulation chamber method, soil CO2 flux survey has been carried out in VGFs (i.e., Jidaguo, Ningzhong, Sanglai, Tuoma and Yuzhai from south to north) of the northern segment of GYR. Total soil CO2 output of the northern GYR is about 1.50 × 107 t a-1, which is attributed to biogenic and volcanic-geothermal source. Geochemical characteristics of the volcanic-geothermal gases (including CO2 and He) of the northern GYR indicate their significant mantle-derived affinities. Combined with previous petrogeochemical and geophysical data, our He-C isotope modeling calculation results show that (1) excess mantle-derived 3He reflects degassing of volatiles related with partial melts from enriched mantle wedge induced by northward subduction of the Indian lithosphere, and (2) the crust-mantle interaction can provide continuous heat and materials for the overlying volcanic-geothermal system, in which magma-derived volatiles are inferred to experience significant crustal contamination during their migration to the surface.

  19. The Arizona striped whiptail: past and present

    Science.gov (United States)

    Brian K. Sullivan; Paul S. Hamilton; Matthew A. Kwiatkowski

    2005-01-01

    We surveyed historic and nearby collecting localities for Aspidoscelis (= Cnemidophorus) arizonae in Cochise and Graham Counties, Arizona, during spring and summer, 2000-2003. Aspidoscelis arizonae was present at or nearby all but one of the historic sites (seven of eight) that we surveyed located near Willcox (...

  20. The Uneven Performance of Arizona's Charter Schools

    Science.gov (United States)

    Chingos, Matthew M.; West, Martin R.

    2015-01-01

    Arizona enrolls a larger share of its students in charter schools than any other state in the country, but no comprehensive examination exists of the impact of those schools on student achievement. Using student-level data covering all Arizona students from 2006 to 2012, we find that the performance of charter schools in Arizona in improving…

  1. A new rapid and non-destructive method to detect tephra layers and cryptotephras: applying to the first distal tephrostratigraphic record of the Chaîne des Puys volcanic field (France).

    Science.gov (United States)

    Jouannic, Gwénolé; Walter-Simonnet, Anne-Véronique; Bossuet, Gilles; Delabrousse, Eric; Cubizolle, Hervé

    2014-05-01

    Tephrostratigraphy has been considerably developed for 30 years, mainly in palaeo-environmental studies. In such studies, distal tephra layers are important chronological markers, but they are also tools to establish or specify record of past eruptions of a volcanic field. Nowadays, development of effective rapid methods to detect tephra layers in sedimentary records of various compositions is a challenge. Many classic methods for detection of tephra layers, like regular sampling or magnetic susceptibility measurements, have shown their limits. Regular sampling takes a long time, and finding tephra layers remains uncertain. Moreover, magnetic susceptibility maesurements, although it is a non-destructive method, is ineffective when tephra layers are made of volcanic glass shards with differentiated magma composition. X-ray fluorescence (XRF) is also a non-destructive method but it takes a very long time to analyze a core with sufficient high resolution, and measurements only concern the surface of the sediment. We propose a new method allows detection of tephra layers with, for the first time, a 3D resolution: the Computed Tomography Scan (CT- Scan). This method, regularly used in medicine, allows there to obtain pictures of materials density on 3D with inframillimetric measurement ranges. Then, it is possible to detect tephras, cryptotephras (invisible by naked eye), reworked tephra layers even when tephra layers don't outcrop at the surface of the sediment (and are therefore undetectable by usual methods like XRF and magnetic susceptibility). This method has been tried out on tephras sedimented in different types of sediments (silicated, carbonated and organic matter). Our results show that this method is very efficient for peaty environment. Used on coring carried out in Forez Mountains (French Massif Central), CT-Scan allows to detect more tephra layers than usual methods (XRF and magnetic susceptibility). Results presented here allow to build the first

  2. H, O, Sr, Nd, and Pb isotope geochemistry of the Latir volcanic field and cogenetic intrusions, New Mexico, and relations between evolution of a continental magmatic center and modifications of the lithosphere

    Science.gov (United States)

    Johnson, C.M.; Lipman, P.W.; Czamanske, G.K.

    1990-01-01

    Over 200 H, O, Sr, Nd, and Pb isotope analyses, in addition to geologic and petrologic constraints, document the magmatic evolution of the 28.5-19 Ma Latir volcanic field and associated intrusive rocks, which includes multiple stages of crustal assimilation, magma mixing, protracted crystallization, and open- and closed-system evolution in the upper crust. In contrast to data from younger volcanic centers in northern New Mexico, relatively low and restricted primary ??18O values (+6.4 to +7.4) rule out assimilation of supracrustal rocks enriched in 18O. Initial 87Sr/86Sr ratios (0.705 to 0.708), ??18O values (-2 to-7), and 206Pb/204Pb ratios (17.5 to 18.4) of metaluminous precaldera volcanic rocks and postcaldera plutonic rocks suggest that most Latir rocks were generated by fractional crystallization of substantial volumes of mantle-derived basaltic magma that had near-chondritic Nd isotope ratios, accompanied by assimilation of crustal material in two main stages: 1) assimilation of non-radiogenic lower crust, followed by 2) assimilation of middle and upper crust by inter-mediate-composition magmas that had been contaminated during the first stage. Magmatic evolution in the upper crust peaked with eruption of the peralkaline Amalia Tuff (???26 Ma), which evolved from metaluminous parental magmas. A third stage of late, roofward assimilation of Proterozoic rocks in the Amalia Tuff magma is indicated by trends in initial 87Sr/86Sr and 206Pb/204Pb ratios from 0.7057 to 0.7098 and 19.5 to 18.8, respectively, toward the top of the pre-eruptive magma chamber. Highly evolved postcaldera plutons are generally fine grained and are zoned in initial 87Sr/86Sr and 206Pb/204Pb ratios, varying from 0.705 to 0.709 and 17.8 to 18.6, respectively. In contrast, the coarser-grained Cabresto Lake (???25 Ma) and Rio Hondo (???21 Ma) plutons have relatively homogeneous initial 87Sr/86Sr and 206Pb/204Pb ratios of approximately 0.7053 and 17.94 and 17.55, respectively. ??18O values for

  3. An ignimbrite caldera from the bottom up: Exhumed floor and fill of the resurgent Bonanza caldera, Southern Rocky Mountain volcanic field, Colorado

    Science.gov (United States)

    Lipman, Peter W.; Zimmerer, Matthew J.; McIntosh, William C.

    2015-01-01

    Among large ignimbrites, the Bonanza Tuff and its source caldera in the Southern Rocky Mountain volcanic field display diverse depositional and structural features that provide special insights concerning eruptive processes and caldera development. In contrast to the nested loci for successive ignimbrite eruptions at many large multicyclic calderas elsewhere, Bonanza caldera is an areally isolated structure that formed in response to a single ignimbrite eruption. The adjacent Marshall caldera, the nonresurgent lava-filled source for the 33.9-Ma Thorn Ranch Tuff, is the immediate precursor for Bonanza, but projected structural boundaries of two calderas are largely or entirely separate even though the western topographic rim of Bonanza impinges on the older caldera. Bonanza, source of a compositionally complex regional ignimbrite sheet erupted at 33.12 ± 0.03 Ma, is a much larger caldera system than previously recognized. It is a subequant structure ∼20 km in diameter that subsided at least 3.5 km during explosive eruption of ∼1000 km3 of magma, then resurgently domed its floor a similar distance vertically. Among its features: (1) varied exposure levels of an intact caldera due to rugged present-day topography—from Paleozoic and Precambrian basement rocks that are intruded by resurgent plutons, upward through precaldera volcanic floor, to a single thickly ponded intracaldera ignimbrite (Bonanza Tuff), interleaved landslide breccia, and overlying postcollapse lavas; (2) large compositional gradients in the Bonanza ignimbrite (silicic andesite to rhyolite ignimbrite; 60%–76% SiO2); (3) multiple alternations of mafic and silicic zones within a single ignimbrite, rather than simple upward gradation to more mafic compositions; (4) compositional contrasts between outflow sectors of the ignimbrite (mainly crystal-poor rhyolite to east, crystal-rich dacite to west); (5) similarly large compositional diversity among postcollapse caldera-fill lavas and resurgent

  4. Residential Energy Efficiency Potential: Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Eric J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-16

    Energy used by Arizona single-family homes that can be saved through cost-effective improvements. Prepared by Eric Wilson and Noel Merket, NREL, and Erin Boyd, U.S. Department of Energy Office of Energy Policy and Systems Analysis.

  5. A Melioidosis Case in Arizona

    Centers for Disease Control (CDC) Podcasts

    2011-10-03

    David Blaney, Medical Officer, Bacterial Special Pathogens Branch, discusses an unusual melioidosis case in Arizona.  Created: 10/3/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 10/5/2011.

  6. Boots on the Ground: Arizona

    Centers for Disease Control (CDC) Podcasts

    2013-12-26

    In this podcast, we talk to CDC public health advisor Lisa Speissegger about her response efforts during the 2013 Arizona wildfires.  Created: 12/26/2013 by Office of Public Health Preparedness and Response (PHPR).   Date Released: 12/26/2013.

  7. Crustal-scale recycling in caldera complexes and rift zones along the Yellowstone hotspot track: O and Hf isotopic evidence in diverse zircons from voluminous rhyolites of the Picabo volcanic field, Idaho

    Science.gov (United States)

    Drew, Dana L.; Bindeman, Ilya N.; Watts, Kathryn E.; Schmitt, Axel K.; Fu, Bin; McCurry, Michael

    2013-11-01

    Rhyolites of the Picabo volcanic field (10.4-6.6 Ma) in eastern Idaho are preserved as thick ignimbrites and lavas along the margins of the Snake River Plain (SRP), and within a deep (>3 km) borehole near the central axis of the Yellowstone hotspot track. In this study we present new O and Hf isotope data and U-Pb geochronology for individual zircons, O isotope data for major phenocrysts (quartz, plagioclase, and pyroxene), whole rock Sr and Nd isotope ratios, and whole rock geochemistry for a suite of Picabo rhyolites. We synthesize our new datasets with published Ar-Ar geochronology to establish the eruptive framework of the Picabo volcanic field, and interpret its petrogenetic history in the context of other well-studied caldera complexes in the SRP. Caldera complex evolution at Picabo began with eruption of the 10.44±0.27 Ma (U-Pb) Tuff of Arbon Valley (TAV), a chemically zoned and normal-δ18O (δ18O magma=7.9‰) unit with high, zoned 87Sr/86Sri (0.71488-0.72520), and low-ɛNd(0) (-18) and ɛHf(0) (-28). The TAV and an associated post caldera lava flow possess the lowest ɛNd(0) (-23), indicating ˜40-60% derivation from the Archean upper crust. Normal-δ18O rhyolites were followed by a series of lower-δ18O eruptions with more typical (lower crustal) Sr-Nd-Hf isotope ratios and whole rock chemistry. The voluminous 8.25±0.26 Ma West Pocatello rhyolite has the lowest δ18O value (δ18Omelt=3.3‰), and we correlate it to a 1,000 m thick intracaldera tuff present in the INEL-1 borehole (with published zircon ages 8.04-8.35 Ma, and similarly low-δ18O zircon values). The significant (4-5‰) decrease in magmatic-δ18O values in Picabo rhyolites is accompanied by an increase in zircon δ18O heterogeneity from ˜1‰ variation in the TAV to >5‰ variation in the late-stage low-δ18O rhyolites, a trend similar to what is characteristic of Heise and Yellowstone, and which indicates remelting of variably hydrothermally altered tuffs followed by rapid batch

  8. Crustal-scale recycling in caldera complexes and rift zones along the Yellowstone hotspot track: O and Hf isotopic evidence in diverse zircons from voluminous rhyolites of the Picabo volcanic field, Idaho

    Science.gov (United States)

    Drew, Dana L.; Bindeman, Ilya N.; Watts, Kathryn E.; Schmitt, Axel K.; Fu, Bin; McCurry, Michael

    2013-01-01

    Rhyolites of the Picabo volcanic field (10.4–6.6 Ma) in eastern Idaho are preserved as thick ignimbrites and lavas along the margins of the Snake River Plain (SRP), and within a deep (>3 km) borehole near the central axis of the Yellowstone hotspot track. In this study we present new O and Hf isotope data and U–Pb geochronology for individual zircons, O isotope data for major phenocrysts (quartz, plagioclase, and pyroxene), whole rock Sr and Nd isotope ratios, and whole rock geochemistry for a suite of Picabo rhyolites. We synthesize our new datasets with published Ar–Ar geochronology to establish the eruptive framework of the Picabo volcanic field, and interpret its petrogenetic history in the context of other well-studied caldera complexes in the SRP. Caldera complex evolution at Picabo began with eruption of the 10.44±0.27 Ma (U–Pb) Tuff of Arbon Valley (TAV), a chemically zoned and normal-δ18O (δ18O magma=7.9‰) unit with high, zoned 87Sr/86Sri (0.71488–0.72520), and low-εNd(0) (−18) and εHf(0) (−28). The TAV and an associated post caldera lava flow possess the lowest εNd(0) (−23), indicating ∼40–60% derivation from the Archean upper crust. Normal-δ18O rhyolites were followed by a series of lower-δ18O eruptions with more typical (lower crustal) Sr–Nd–Hf isotope ratios and whole rock chemistry. The voluminous 8.25±0.26 Ma West Pocatello rhyolite has the lowest δ18O value (δ18Omelt=3.3‰), and we correlate it to a 1,000 m thick intracaldera tuff present in the INEL-1 borehole (with published zircon ages 8.04–8.35 Ma, and similarly low-δ18O zircon values). The significant (4–5‰) decrease in magmatic-δ18O values in Picabo rhyolites is accompanied by an increase in zircon δ18O heterogeneity from ∼1‰ variation in the TAV to >5‰ variation in the late-stage low-δ18O rhyolites, a trend similar to what is characteristic of Heise and Yellowstone, and which indicates remelting of variably hydrothermally altered tuffs

  9. Silicate volcanism on Io

    Science.gov (United States)

    Carr, M. H.

    1986-03-01

    This paper is mainly concerned with the nature of volcanic eruptions on Io, taking into account questions regarding the presence of silicates or sulfur as principal component. Attention is given to the generation of silicate magma, the viscous dissipation in the melt zone, thermal anomalies at eruption sites, and Ionian volcanism. According to the information available about Io, it appears that its volcanism and hence its surface materials are dominantly silicic. Several percent of volatile materials such as sulfur, but also including sodium- and potassium-rich materials, may also be present. The volatile materials at the surface are continually vaporized and melted as a result of the high rates of silicate volcanism.

  10. geochemistry of the potassic basalts from the bufumbira volcanic

    African Journals Online (AJOL)

    Mgina

    ABSTRACT. Bufumbira volcanic field is the southernmost of the four Ugandan small Pleistocene to Recent volcanic fields within the western branch of the East African rift system. The rocks consist of silica undersaturated and vesicular basalts with numerous primary structures. The rocks consist of basanites, leucitites ...

  11. Melt inclusions are not reliable proxies for magmatic liquid composition: evidence from crystal-poor andesites and dacites in the Tequila volcanic field, Mexico

    Science.gov (United States)

    Frey, H. M.; Lange, R. A.

    2009-12-01

    A compositional study of >200 melt inclusions in plagioclase and orthopyroxene phenocrysts from six crystal-poor (2-5 vol%) andesite and dacite lavas (60-68 wt% SiO2) from the Tequila volcanic field in the Mexico arc is used to evaluate whether melt inclusions in phenocrysts accurately record magmatic liquid compositions. The crystal-poor andesites and dacites were erupted contemporaneously with crystal-poor rhyolites, and there is a continuum in the SiO2 concentration of the erupted magmas. The liquid line of descent defined by the whole-rock compositions ranges from andesite to rhyolite (60-77 wt% SiO2), as illustrated on Harker diagrams. The crystal-poor andesites and dacites are multiply saturated with five to seven mineral phases (plagioclase + orthopyroxene + titanomagnetite + ilmenite + apatite ± augite ± hornblende), most of which crystallized via degassing during magma ascent (Frey and Lange, 2009). By comparison with phase equilibrium experiments from the literature, it is shown that the vast majority of crystals are phenocrysts and not xenocrysts. Textural evidence of rapid crystal growth includes skeletal, hopper, and swallow-tail morphologies and abundant melt inclusions. The inclusions range in size from a few microns to > 50 μm and occur as isolated pockets and extensive channels that mimic the crystal morphology. Inclusions are typically brown glass, with occasional microphenocrysts of titanomagnetite and/or apatite within or adjacent to the melt inclusions. The compositions of the melt inclusions in the plagioclase and orthopyroxene phenocrysts, when plotted on Harker diagrams, vary systematically from one another and from the liquid line of descent defined by the whole rock compositions of erupted magmas. For example, melt inclusions in plagioclase are systematically depleted in Al2O3 relative to the whole rock samples, whereas those in coexisting orthopyroxenes are systematically enriched in Al2O3. The opposite trend is found for FeO, where it

  12. Petrography and geochemistry of achnelithic tephra from Las Herrerías Volcano (Calatrava volcanic field, Spain): Formation of nephelinitic achneliths and post-depositional glass alteration

    Science.gov (United States)

    Carracedo-Sánchez, M.; Sarrionandia, F.; Arostegui, J.; Errandonea-Martin, J.; Gil-Ibarguchi, J. I.

    2016-11-01

    We present the results of a petrographic and geochemical study carried out on a layer of achnelithic tephra outcropping at the base of the volcanic cone of Las Herrerías (Miocene-Quaternary volcanic region of Campo de Calatrava, Spain). The tephra, with a composition of nephelinite and ash (shapes of these pyroclasts and their welding above the glass transition temperature (533-669 °C). The sideromelane glass of the achneliths, also nephelinitic in composition, is variably altered to palagonite. The palagonitization was isovolumetric and took place in a near closed system at the achnelith scale. Palagonitization involved depletion in the concentration (g/cm3) of all major elements and notable increase in H2O content. The elements liberated by this process formed smectite with an average structural formula comprised between those of beidellite and nontronite end terms: (Na0.01K0.03Ca0.18) (Mg0.22Fe0.16)2 + (Fe0.48Al1.02)3 + (Ti0.18)4 + (Si3.58Al0.42) O10(OH)2. The degree of palagonitization in each achnelith was likely related to the amount of water incorporated by individual clasts at the moment of their deposition in a volcanic maar lake. Afterwards, there was no more water circulation through the achnelithic tephra, which was sealed from water by overlying hydrovolcanic tuff deposits. It was this isolation that made possible the preservation of glass to the present day.

  13. Center for Volcanic and Tectonic Studies, Department of Geoscience annual report, October 1, 1989--September 30, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Smith, E.I. [Nevada Univ., Las Vegas, NV (United States). Center for Volcanic and Tectonic Studies

    1990-11-01

    This report summarizes our activities during the period October 1, 1989 to September 30, 1990. Our goal was to develop an understanding of late-Miocene and Pliocene volcanism in the Great Basin by studying Pliocene volcanoes in the vicinity of the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. Field studies during this period concentrated on the Quaternary volcanoes in Crater Flat, Yucca Mountain, Fortification Hill, at Buckboard Mesa and Sleeping Butte, and in the Reveille Range. Also, a study was initiated on structurally disrupted basaltic rocks in the northern White Hills of Mohave County, Arizona. As well as progress reports of our work in Crater Flat, Fortification Hill and the Reveille Range, this paper also includes a summary of model that relates changing styles of Tertiary extension to changing magmatic compositions, and a summary of work being done in the White Hills, Arizona. In the Appendix, we include copies of published papers not previously incorporated in our monthly reports.

  14. Is The Chapala-Oaxaca Fault The Souhtern Boundary of the Michoacan-Guanajuato Volcanic Field As inferrred From Magnetic data?

    Science.gov (United States)

    Rosas-Elguera, J.; Lopez-Loera, H.; Fregoso, E.; Flores, R. M., Sr.; Peña, L.

    2016-12-01

    On the basis of previous structural and new geophysical data, we propose that: (1) the continental boundaries of the Michoacan block are early structures reactivated since the Pliocene to Quaternary contributing to development of volcanism along it and (2) previously, Rosas-Elguera et al. (1996) proposed that Pliocene-Quaternary extensional faulting at the western edge of Michoacan block is a basement-controlled intraplate deformation related to plate boundary forces rather than to active continental rifting. Here we propose the NW boundary is formed by three segments: the Cotija half-graben, the Paricutin zone and the Jorullo zone.

  15. The Timber Mountain magmato-thermal event: An intense widespread culmination of magmatic and hydrothermal activity at the southwestern Nevada volcanic field

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Jr., Mac Roy [Univ. of Nevada, Reno, NV (United States)

    1988-05-01

    Eruption of the Rainier Mesa and Ammonia Tanks Members Timber Mountain Tuff at about 11.5 and 11.3 Ma, respectively, resulted in formation of the timber Mountain (TM) caldera; new K-Ar ages show that volcanism within and around the TM caldera continued for about 1 m.y. after collapse. Some TM age magmatic activity took place west and southeast of the TM caldera in the Beatty -- Bullfrog Hills and Shoshone Mountain areas, suggesting that volcanic activity at the TM caldera was an intense expression of an areally extensive magmatic system active from about 11.5 to 10Ma. Epithermal Au-Ag, Hg and fluorite mineralization and hydrothermal alteration are found in both within and surrounding the Timber Mountain -- Oasis Valley caldera complex. New K-Ar ages date this hydrothermal activity between about 13 and 10 Ma, largely between about 11.5 and 10 Ma, suggesting a genetic relation of hydrothermal activity to the TM magmatic system.

  16. Impaired Water 303(d) Polygons, Arizona, 2004, Arizona Department of Environmental Quality

    Data.gov (United States)

    U.S. Environmental Protection Agency — Arizona 303(d) waterbodies for 2004. These include lakes, reservoirs, ponds, etc. The 303(d) list is a related table to the feature class AZ_303d_04_area. Arizona's...

  17. Volcanic signals in oceans

    KAUST Repository

    Stenchikov, Georgiy L.

    2009-08-22

    Sulfate aerosols resulting from strong volcanic explosions last for 2–3 years in the lower stratosphere. Therefore it was traditionally believed that volcanic impacts produce mainly short-term, transient climate perturbations. However, the ocean integrates volcanic radiative cooling and responds over a wide range of time scales. The associated processes, especially ocean heat uptake, play a key role in ongoing climate change. However, they are not well constrained by observations, and attempts to simulate them in current climate models used for climate predictions yield a range of uncertainty. Volcanic impacts on the ocean provide an independent means of assessing these processes. This study focuses on quantification of the seasonal to multidecadal time scale response of the ocean to explosive volcanism. It employs the coupled climate model CM2.1, developed recently at the National Oceanic and Atmospheric Administration\\'s Geophysical Fluid Dynamics Laboratory, to simulate the response to the 1991 Pinatubo and the 1815 Tambora eruptions, which were the largest in the 20th and 19th centuries, respectively. The simulated climate perturbations compare well with available observations for the Pinatubo period. The stronger Tambora forcing produces responses with higher signal-to-noise ratio. Volcanic cooling tends to strengthen the Atlantic meridional overturning circulation. Sea ice extent appears to be sensitive to volcanic forcing, especially during the warm season. Because of the extremely long relaxation time of ocean subsurface temperature and sea level, the perturbations caused by the Tambora eruption could have lasted well into the 20th century.

  18. Assessing Volcanic Risk in Saudi Arabia

    Science.gov (United States)

    Lindsay, Jan Marie; Rashad Moufti, Mohammed

    2014-08-01

    The Kingdom of Saudi Arabia has numerous large monogenetic volcanic fields, known locally as "harrats." The largest of these, Harrat Rahat (Figure 1), produced a basaltic fissure eruption in 1256 C.E. with lava flows traveling within 20 kilometers of the city Al-Madinah, which currently has a population of 1.5 million plus an additional 3 million pilgrims annually. With more than 950 visible vents and periodic seismic swarms, an understanding of the risk of future eruptions in this volcanic field is vital.

  19. 76 FR 28079 - Notice of Intent To Repatriate Cultural Items: Arizona State Museum, University of Arizona...

    Science.gov (United States)

    2011-05-13

    ... National Park Service Notice of Intent To Repatriate Cultural Items: Arizona State Museum, University of... intent to repatriate cultural items in the possession of the Arizona State Museum, University of Arizona... determinations in this notice are the sole responsibility of the museum, institution, or Federal agency that has...

  20. First data on the environment and climate change within the Zhom-Bolok volcanic field (Eastern Sayan Mountains) in the Middle-Late Holocene

    Science.gov (United States)

    Bezrukova, E. V.; Shchetnikov, A. A.; Kuzmin, M. I.; Sharova, O. G.; Kulagina, N. V.; Letunova, P. P.; Ivanov, E. V.; Kraynov, M. A.; Kerber, E. V.; Filinov, I. A.; Levina, O. V.

    2016-05-01

    This paper considers the results of comprehensive lithological, biostratigraphic, and geochemical investigation of sediments in Khara-Nur Lake (Eastern Sayan Mountains) situated in the area of the greatest Holocene eruptions in the Central Asia Region. The age of the basal sediment layer is estimated at 6881 ± 53 years. The local natural environment and climate have undergone great changes since that time. The Holocene volcanic events did not exert a catastrophic impact on the regional landscape, but they caused dramatic changes in the local vegetation. The well-defined correlation of the regional events with the well-known records of the natural environment in the Northern Hemisphere is indicative of the decisive influence of global atmospheric circulation on restructuring the landscape and climate system in the Zhom-Bolok Region in the Middle-Late Holocene.

  1. 40Ar/(39Ar) geochronology of rhyolites erupted following collapse of the Yellowstone caldera, Yellowstone Plateau volcanic field: implications for crustal contamination

    Science.gov (United States)

    Gansecki, C. A.; Mahood, G. A.; McWilliams, M. O.

    1996-07-01

    Single-crystal laser-probe 40Ar 39Ar dating of 133 grains of sanidine and plagioclase has enabled us to resolve the eruption ages of the Upper Basin Member rhyolites — the lava flows and related tuffs that erupted within the Yellowstone Caldera shortly after its collapse 630 ky ago on eruption of the Lava Creek Tuff. Two lavas and a tuff that erupted from the eastern ring-fracture zone yield an eruptive age of 481 ± 8 ka, whereas two flows from the western ring-fracture zone yield eruptive ages of 516 ± 7 and 198 ± 8 ka. Most of the units contain old xenocrysts, explaining why previous attempts at dating these earliest post-caldera units by the conventional K sbnd Ar method yielded poorly resolved and, in some cases, anomalous ages. The tuff shows the most severe contamination. Grains from a single pumice lapilli in the tuff show as large an age range as those from bulk vitrophyre, indicating that the xenocrysts were incorporated in the magma prior to its near-surface explosive fragmentation. Diffusion calculations indicate that the xenocrysts could not have remained in the magma for more than a few years without degassing and giving ages indistinguishable from the phenocrysts. Thus, the contamination represented by the xenocrysts probably occurred during fracturing and conduit propagation, rather than during caldera collapse, which took place more than 100 ky earlier. The apparent ages of xenocrysts and their compositions as determined by electron microprobe suggest that the Eocene Absaroka volcanics are the main contaminant, with a single xenocryst probably coming from Precambrian basement rocks. Most of the xenocrysts are difficult to distinguish optically or chemically from feldspar phenocrysts, illustrating the necessity of single-crystal to date many young volcanic rocks accurately.

  2. Volcanic hazards of the Idaho National Engineering Laboratory and adjacent areas

    Energy Technology Data Exchange (ETDEWEB)

    Hackett, W.R. [WRH Associates, Salt Lake City, UT (United States); Smith, R.P. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)

    1994-12-01

    Potential volcanic hazards are assessed, and hazard zone maps are developed for the Idaho National Engineering Laboratory (INEL) and adjacent areas. The basis of the hazards assessment and mapping is the past volcanic history of the INEL region, and the apparent similarity of INEL volcanism with equivalent, well-studied phenomena in other regions of active volcanism, particularly Hawaii and Iceland. The most significant hazards to INEL facilities are associated with basaltic volcanism, chiefly lava flows, which move slowly and mainly threaten property by inundation or burning. Related hazards are volcanic gases and tephra, and ground disturbance associated with the ascent of magma under the volcanic zones. Several volcanic zones are identified in the INEL area. These zones contain most of the volcanic vents and fissures of the region and are inferred to be the most probable sites of future INEL volcanism. Volcanic-recurrence estimates are given for each of the volcanic zones based on geochronology of the lavas, together with the results of field and petrographic investigations concerning the cogenetic relationships of INEL volcanic deposits and associated magma intrusion. Annual probabilities of basaltic volcanism within the INEL volcanic zones range from 6.2 {times} 10{sup {minus}5} per year (average 16,000-year interval between eruptions) for the axial volcanic zone near the southern INEL boundary and the Arco volcanic-rift zone near the western INEL boundary, to 1 {times} 10{sup {minus}5} per year (average 100,000-year interval between eruptions) for the Howe-East Butte volcanic rift zone, a geologically old and poorly defined feature of the central portion of INEL. Three volcanic hazard zone maps are developed for the INEL area: lava flow hazard zones, a tephra (volcanic ash) and gas hazard zone, and a ground-deformation hazard zone. The maps are useful in land-use planning, site selection, and safety analysis.

  3. Volcanic Rocks and Features

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Volcanoes have contributed significantly to the formation of the surface of our planet. Volcanism produced the crust we live on and most of the air we breathe. The...

  4. Languages of volcanic landscapes

    Science.gov (United States)

    Frederick J. Swanson

    2008-01-01

    As a young geologist in 1980, I felt a powerful attraction to volcanoes, and I thought I knew volcanoes rather well. I had studied volcanology. I had climbed volcanic peaks in the Cascades. And I had tried to be an attentive citizen of my volcanic region, the Pacific Northwest. But when I had a chance to go with other scientists to Mount St. Helens within days of its...

  5. Biogeography of amphibians and reptiles in Arizona

    Science.gov (United States)

    Eric W. Stitt; Theresa M. Mau-Crimmins; Don E. Swann

    2005-01-01

    We examined patterns of species richness for amphibians and reptiles in Arizona and evaluated patterns in species distribution between ecoregions based on species range size. In Arizona, the Sonoran Desert has the highest herpetofauna diversity, and the southern ecoregions are more similar than other regions. There appear to be distinct low- and mid-elevational...

  6. 21 CFR 808.53 - Arizona.

    Science.gov (United States)

    2010-04-01

    ... AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EXEMPTIONS FROM FEDERAL PREEMPTION OF STATE AND LOCAL MEDICAL DEVICE REQUIREMENTS Listing of Specific State and Local Exemptions § 808.53 Arizona. The following Arizona medical device requirements are preempted...

  7. The pace of arc volcanism

    Science.gov (United States)

    Palmer, M. R.; Fraass, A. J.; Hatfield, R. G.; McCanta, M. C.

    2016-12-01

    Being able to reconstruct the long-term history of activity at an island arc volcanic centre has important implications for a wide variety of geologic processes. On-land records are frequently incomplete and radiometric dating is complicated in many systems. Here, we describe the application of rapid and non-destructive measurements of sediment physical properties (colour reflectance, gamma ray attenuation and magnetic susceptibility) from marine sediments recovered from IODP site U1396 to produce a tephra index (TI). This approach is combined with palaeomagnetic and foram isotope stratigraphy to yield a 4.5 Myr record of volcanic activity in the northern Lesser Antilles. Pb isotope data on visible tephra layers and volcanological models suggest the tephra is predominantly derived from the nearby island of Montserrat. When examined over a range of time-averaged intervals, the TI record shows long term (order 106 year) cycles of relative quiescence and heightened activity. In accordance with the model of Hall & Kincaid (2001, Science, 292, 2472), this record suggests that the long-term pace of volcanic activity in the northern Lesser Antilles is established by diapirs rising from deep within the mantle wedge. The diapirs do not themselves act as the major source of melt, but rather they create a conduit network that facilitates the rapid rise of melt to the surface. Within the order 106 year cycles, there are shorter-term fluctuations (order 104 years) that may reflect cycles of edifice growth and destruction, and/or pulses of melt rising through conduit networks established by the rising diapirs. The U1396 TI record provides the most complete and non-aliased long-term record of activity at an island arc volcanic center yet determined. It thus provides the first field evidence that can be used to test models of the deep mantle processes that control the pace of arc volcanism. Importantly, the approach presented here is readily applicable to other arc and island

  8. Investigating the Formation and Subsurface Structure of a Large Water-Filled Basaltic Maar Volcano Using Constrained Potential Field Modelling, Lake Purrumbete Maar, Newer Volcanics Province.

    Science.gov (United States)

    van den Hove, J. C.; Ailleres, L.; Betts, P. G.; Cas, R. A. F.

    2014-12-01

    Lake Purrumbete Maar of the Newer Volcanics Province, south-eastern Australia is one of the largest maar volcanoes in the world with a near circular crater up to 2800 m in diameter and hosting a 45 m deep crater lake. Surrounding tephra ring deposits are comprised of cross-bedded fine ash and lapilli-ash deposits typical of efficient subsurface phreatomagmatic eruptive activity. Erupted accessory lithics suggest subsurface phreatomagmatic activity occurred to a depth no greater than 250 m, whilst irregular clast shapes and peperitic textures observed in marl lithics suggest the host rock was poorly consolidated during eruptive activity. To further understand factors controlling Lake Purrumbete Maars immense size, high resolution lake and land-based gravity and magnetic data were collected for use in forward modelling of the subsurface architecture associated with the maar. Collection of gravity data presented a unique challenge due to the nature of measuring small changes in gravitational forces (structure, consistent with maars hosted within poorly consolidated sediments. 2.5-D forward models were used to produce a 3-D reference model for property and geometry inversions, to test and optimise the modelled features. Inversions suggest the major vents likely occur to a greater depth than 240 m as suggested in the initial reference model.

  9. LOWER SAN FRANCISCO WILDERNESS STUDY AREA AND CONTIGUOUS ROADLESS AREAS, ARIZONA AND NEW MEXICO.

    Science.gov (United States)

    Ratte, James C.; Lane, Michael

    1984-01-01

    The Lower San Francisco study area consists of about 40 sq mi, in a strip between 1 and 6 mi wide, along a 20-30 mi stretch of the San Francisco River in Arizona and New Mexico. The study area and contiguous roadless areas were examined for mineral potential and found to have an area of probable mineral-resource potential for base- or precious-metal deposits in middle to upper Tertiary volcanic rocks. The entire area has a largely unassessable potential for base-metal deposits related to igneous intrusives of Laramide age, like those in the nearby Morenci mining district, Arizona. The contiguous roadless area has an area of probable mineral-resource potential for molybdenum or copper deposits related to intrusive igneous rocks in the core of a dacitic volcano of Oligocene age. An area in the west part of the study area has a probable geothermal-resource potential.

  10. Volcanic hazards to airports

    Science.gov (United States)

    Guffanti, M.; Mayberry, G.C.; Casadevall, T.J.; Wunderman, R.

    2009-01-01

    Volcanic activity has caused significant hazards to numerous airports worldwide, with local to far-ranging effects on travelers and commerce. Analysis of a new compilation of incidents of airports impacted by volcanic activity from 1944 through 2006 reveals that, at a minimum, 101 airports in 28 countries were affected on 171 occasions by eruptions at 46 volcanoes. Since 1980, five airports per year on average have been affected by volcanic activity, which indicates that volcanic hazards to airports are not rare on a worldwide basis. The main hazard to airports is ashfall, with accumulations of only a few millimeters sufficient to force temporary closures of some airports. A substantial portion of incidents has been caused by ash in airspace in the vicinity of airports, without accumulation of ash on the ground. On a few occasions, airports have been impacted by hazards other than ash (pyroclastic flow, lava flow, gas emission, and phreatic explosion). Several airports have been affected repeatedly by volcanic hazards. Four airports have been affected the most often and likely will continue to be among the most vulnerable owing to continued nearby volcanic activity: Fontanarossa International Airport in Catania, Italy; Ted Stevens Anchorage International Airport in Alaska, USA; Mariscal Sucre International Airport in Quito, Ecuador; and Tokua Airport in Kokopo, Papua New Guinea. The USA has the most airports affected by volcanic activity (17) on the most occasions (33) and hosts the second highest number of volcanoes that have caused the disruptions (5, after Indonesia with 7). One-fifth of the affected airports are within 30 km of the source volcanoes, approximately half are located within 150 km of the source volcanoes, and about three-quarters are within 300 km; nearly one-fifth are located more than 500 km away from the source volcanoes. The volcanoes that have caused the most impacts are Soufriere Hills on the island of Montserrat in the British West Indies

  11. Displacement rates on the Toroweap and Hurricane faults: Implications for Quaternary downcutting in the Grand Canyon, Arizona

    Science.gov (United States)

    Fenton, Cassandra R.; Webb, Robert H.; Pearthree, Philip A.; Cerling, Thure E.; Poreda, Robert J.

    2001-11-01

    The Toroweap and Hurricane faults, considered to be the most active in Arizona, cross the Uinkaret volcanic field in the western Grand Canyon. These normal faults are downthrown to the west, and the Colorado River crosses these faults as it flows west in the Grand Canyon. Cosmogenic 3He (3Hec) dates on basalt flows and related landforms are used to calculate vertical displacement rates for these faults. The two faults cross unruptured alluvial fans dated as 3 ka (Toroweap) and 8 ka (Hurricane), and 10 other landforms that range in age from 30 to 400 ka are displaced. Middle and late Quaternary displacement rates of the Toroweap and Hurricane faults are 70 180 and 70 170 m/m.y., respectively. On the basis of these rates, the combined displacement of 580 m on these faults could have occurred in the past 3 to 5 m.y. All 3Hec dates are younger than existing K- Ar dates and are consistent with new 40Ar/39Ar dates and existing thermoluminescence (TL) dates on basalt flows. These different dating techniques may be combined in an analysis of displacement rates. Downcutting rates for the Colorado River in the eastern Grand Canyon (400 m/m.y.) are at least double the downcutting rates west of the faults (70 160 m/m.y.). Faulting probably increased downcutting in the eastern Grand Canyon relative to downcutting in the western Grand Canyon during the late Quaternary.

  12. Seismic scanning tunneling macroscope - Elastic simulations and Arizona mine test

    KAUST Repository

    Hanafy, Sherif M.

    2012-01-01

    Elastic seismic simulations and field data tests are used to validate the theory of a seismic scanning tunneling macroscope (SSTM). For nearfield elastic simulation, the SSTM results show superresolution to be better than λ/8 if the only scattered data are used as input data. If the direct P and S waves are muted then the resolution of the scatterer locations are within about λ/5. Seismic data collected in an Arizona tunnel showed a superresolution limit of at least λ/19. These test results are consistent with the theory of the SSTM and suggest that the SSTM can be a tool used by geophysicists as a probe for near-field scatterers.

  13. Arizona Geology Trip - February 25-28, 2008

    Science.gov (United States)

    Thomas, Gretchen A.; Ross, Amy J.

    2008-01-01

    A variety of hardware developers, crew, mission planners, and headquarters personnel traveled to Gila Bend, Arizona, in February 2008 for a CxP Lunar Surface Systems Team geology experience. Participating in this field trip were the CxP Space Suit System (EC5) leads: Thomas (PLSS) and Ross (PGS), who presented the activities and findings learned from being in the field during this KC. As for the design of a new spacesuit system, this allowed the engineers to understand the demands this type of activity will have on NASA's hardware, systems, and planning efforts. The engineers also experienced the methods and tools required for lunar surface activity.

  14. "By the Time I Get to Arizona": Race, Language, and Education in America's Racist State

    Science.gov (United States)

    Cammarota, Julio; Aguilera, Michelle

    2012-01-01

    This article reports on research projects conducted primarily by first and second generation Mexican American high school students who document how school relationships are shaped by Arizona's racist political discourses. They conducted observations of their school experiences and then wrote up what they were observing in field notes. Field note…

  15. Arizona black rattlesnake (Crotalus viridis cerberus)

    Science.gov (United States)

    Nowak, Erika M.

    2006-01-01

    The Arizona black rattlesnake makes its home at higher elevations in Arizona and far western New Mexico. The snake's use of high-altitude habitat and its black coloration as an adult distinguishes it from other subspecies of the western rattlesnake (Crotalus viridis), which prefer lower elevations and range from tan to reddish in color as adults. These physical and habitat differences are also reflected in genetic differences that suggest that the Arizona black rattlesnake may be a new species of rattlesnake. Despite the species's limited range, basic biological information needed to make management decisions is lacking for most Arizona black rattlesnake populations. To address this need, U.S. Geological Survey (USGS) scientists conducted research on the species in Arizona national park units from 2003 to 2005. The research examined relative population abundance, movement patterns, range requirements, dietary habits, and winter and summer habitat. Research in Arizona national parks was made possible through the support of the Western National Parks Association, Tonto National Monument, and the USGS Science Internships for Workforce Diversity Program. Importantly, the park-based research was used to augment a long-term mark-recapture study of the species that has been conducted by USGS biologists at sites near Flagstaff, Arizona, since 1999. USGS researchers were the first to conduct extensive studies of this species in the wild.

  16. Precambrian Lunar Volcanic Protolife

    Directory of Open Access Journals (Sweden)

    Jack Green

    2009-06-01

    Full Text Available Five representative terrestrial analogs of lunar craters are detailed relevant to Precambrian fumarolic activity. Fumarolic fluids contain the ingredients for protolife. Energy sources to derive formaldehyde, amino acids and related compounds could be by flow charging, charge separation and volcanic shock. With no photodecomposition in shadow, most fumarolic fluids at 40 K would persist over geologically long time periods. Relatively abundant tungsten would permit creation of critical enzymes, Fischer-Tropsch reactions could form polycyclic aromatic hydrocarbons and soluble volcanic polyphosphates would enable assembly of nucleic acids. Fumarolic stimuli factors are described. Orbital and lander sensors specific to protolife exploration including combined Raman/laser-induced breakdown spectrocsopy are evaluated.

  17. Volcanic activity and climatic changes.

    Science.gov (United States)

    Bryson, R A; Goodman, B M

    1980-03-07

    Radiocarbon dates of volcanic activity suggest variations that appear to be related to climatic changes. Historical eruption records also show variations on the scale of years to centuries. These records can be combined with simple climatic models to estimate the impact of various volcanic activity levels. From this analysis it appears that climatic prediction in the range of 2 years to many decades requires broad-scale volcanic activity prediction. Statistical analysis of the volcanic record suggests that some predictability is possible.

  18. Modeling volcanic ash dispersal

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard...

  19. Miocene to quaternary volcanism in eastern Kenya: Sequence and geochronology

    Science.gov (United States)

    Brotzu, P.; Morbidelli, L.; Nicoletti, M.; Piccirillo, E. M.; Traversa, G.

    1984-01-01

    This paper presents the results of the first systematic geochronological study of widespread volcanic sequences in the region east of the Kenya Rift Valley between the Nyambeni Hills near the equator and the Hurri Hills-Dukana area close to the Ethiopian border. Volcanic activity in this area developed from Upper Miocene to Quaternary. Miocene activity (12-5 m.y.) was of fissure-type while the Plio-Quaternary volcanism was mainly of central type. This last volcanism occurred from early Pliocene (4.5 m.y.) to Recent (0.5 m.y.). The products of the two volcanic phases can be distinguished also from a compositional point of view. Previous stratigraphical interpretations are discussed on the basis of field and laboratory evidence.

  20. High-frequency paleoclimate signals from Foulden Maar, Waipiata Volcanic Field, southern New Zealand: An Early Miocene varved lacustrine diatomite deposit

    Science.gov (United States)

    Lindqvist, Jon K.; Lee, Daphne E.

    2009-12-01

    A freshwater diatomite deposit near Dunedin, South Island, New Zealand provides an exceptional archive of mid-latitude, seasonal climate variation during latest Oligocene-early Early Miocene time. The diatomite accumulated in a small ~ 1.5 km diameter maar-floored lake that formed during basaltic volcanism. Except for exposures of basanite dated at 23.2 Ma by 40Ar/ 39Ar, and remnants of a Paleogene sandstone and conglomerate cover, the diatomite body is surrounded by Otago Schist. Geophysical profiles indicate that the total diatomaceous sediment thickness may exceed 100 m. Two depositional facies are described from 15.5 m of weakly-consolidated fresh diatomite accessible in two pits. A thinly laminated facies, comprising 60% of the section, consists of dark brown and white couplets of average thickness 0.5 mm. Both brown and white laminae are composed essentially of frustules of a single pennate diatom, along with 1-2% of siliceous sponge spicules. Dark laminae also contain abundant 5-7.5 µm diameter siliceous chrysophycean stomatocysts and organic matter. Decalcified complete skeletons of Galaxias, a southern hemisphere group of freshwater or diadromous fish, are found throughout. Diverse well-preserved leaves, some with attached scale insects, are dominated by Lauraceae. Rare flowers are also present. Trace fossils preserved in the laminated comprise 1-1.5 mm wide pale diatomaceous strings of probable faecal origin, and isolated 20-40 mm diameter sand lenses interpreted as faecal remains of swimming waterfowl. The second diatomite facies group comprises dark brown speckled beds, interpreted as sediment gravity flows. Up to 14 cm thick and interspersed throughout the study section, they incorporate abundant laminated diatomite flecks and leaves, and minor woody plant matter and terrigenous silt. Almost all are capped by 1-8 mm of white diatomite that is interpreted as post-flow fall-out of resuspended diatom frustules. Associated breccia and swirly beds up to 8

  1. Durham, North Carolina, Students Study Martian Volcanism

    Science.gov (United States)

    2008-01-01

    This image of the wall of a graben a depressed block of land between two parellel faults in Tyrrhena Terra, in Mars' ancient southern highlands, was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at 0914 UTC (4:14 a.m. EST) on February 6, 2008, near 17.3 degrees south latitude, 95.5 degrees east longitude. CRISM's image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 35 meters (115 feet) across. The region covered is just over 10 kilometers (6.2 miles) wide at its narrowest point. This image was part of an investigation planned by students in four high schools in Durham, North Carolina. The students are working with the CRISM science team in a project called the Mars Exploration Student Data Teams (MESDT), which is part of NASA's Mars Public Engagement Program and Arizona State University's Mars Education Program. Starting with a medium-resolution map of the area, taken as part of CRISM's 'multispectral survey' campaign to map Mars in 72 colors at 200 meters (660 feet) per pixel, the students identified a key rock outcrop to test their hypothesis that the irregular depression was formed by Martian volcanism. They provided the coordinates of the target to CRISM's operations team, who took a high-resolution image of the site. The Context Imager (CTX) accompanied CRISM with a 6 meter (20 feet) per pixel, high-resolution image to sharpen the relationship of spectral variations to the underlying surface structures. The Durham students worked with a mentor on the CRISM team to analyze the data, and presented their results at the 39th Lunar and Planetary Science Conference, held in League City, Texas, on March 10-14, 2008. The upper panel of the image shows the location of the CRISM data and the surrounding, larger CTX image, overlain on an image mosaic taken by the Thermal Emission Imaging System (THEMIS) on Mars Odyssey. The mosaic has been color-coded for elevation using data from the Mars Orbiter Laser

  2. Hydrogeology of the Mogollon Highlands, central Arizona

    Science.gov (United States)

    Parker, John T.C.; Steinkampf, William C.; Flynn, Marilyn E.

    2005-01-01

    The Mogollon Highlands, 4,855 square miles of rugged, mountainous terrain at the southern edge of the Colorado Plateau in central Arizona, is characterized by a bedrock-dominated hydrologic system that results in an incompletely integrated regional ground-water system, flashy streamflow, and various local water-bearing zones that are sensitive to drought. Increased demand on the water resources of the area as a result of recreational activities and population growth have made necessary an increased understanding of the hydrogeology of the region. The U.S. Geological Survey conducted a study of the geology and hydrology of the region in cooperation with the Arizona Department of Water Resources under the auspices of the Arizona Rural Watershed Initiative, a program launched in 1998 to assist rural areas in dealing with water-resources issues. The study involved the analysis of geologic maps, surface-water and ground-water flow, and water and rock chemical data and spatial relationships to characterize the hydrogeologic framework. The study area includes the southwestern corner of the Colorado Plateau and the Mogollon Rim, which is the eroded edge of the plateau. A 3,000- to 4,000-foot sequence of early to late Paleozoic sedimentary rocks forms the generally south-facing scarp of the Mogollon Rim. The area adjacent to the edge of the Mogollon Rim is an erosional landscape of rolling, step-like terrain exposing Proterozoic metamorphic and granitic rocks. Farther south, the Sierra Ancha and Mazatzal Mountain ranges, which are composed of various Proterozoic rocks, flank an alluvial basin filled with late Cenozoic sediments and volcanic flows. Eight streams with perennial to intermittent to ephemeral flow drain upland regions of the Mogollon Rim and flow into the Salt River on the southern boundary or the Verde River on the western boundary. Ground-water flow paths generally are controlled by large-scale fracture systems or by karst features in carbonate rocks. Stream

  3. SMEX04 ENVISAT ASAR Data: Arizona

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is comprised of browse images acquired over the regional study area of Arizona, USA for the 2004 Soil Moisture Experiment (SMEX04). The experiment was...

  4. Phenotypic and genotypic characterization of Salmonella arizonae from an integrated turkey operation.

    Science.gov (United States)

    Crespo, R; Jeffrey, J S; Chin, R P; Sentíes-Cué, G; Shivaprasad, H L

    2004-01-01

    Fifty cases submitted between 2000 and 2002 were selected for retrospective analysis to evaluate possible relationships between Salmonella arizonae isolated from breeder flocks, hatching eggs, and meat bird flocks belonging to a single turkey integrator. In all the meat bird cases selected for this study, arizonosis was the primary diagnosis. In birds under 1 month of age, clinical signs and pathologic changes were observed in older birds. The Salmonella arizonae isolates were analyzed by antibiotic resistance pattern and serotype and genotyped by pulsed-field gel electrophoresis (PFGE). Serotyping and PFGE yielded similar results, but the antibiotic resistance patterns did not correspond to either serotyping or PFGE typing. The presence of common pulsed-field patterns in breeder flocks, eggs, and meat bird flocks suggested that S. arizonae was being transmitted vertically from the breeder flock.

  5. July 2013 Arizona thoracic society notes

    OpenAIRE

    Robbins RA

    2013-01-01

    No abstract available. Article truncated after 150 words. The first Arizona Thoracic Society meeting in Tucson was held on Wednesday, 7/24/2013 at Kiewit Auditorium on the University of Arizona Medical Center campus beginning at 6:30 PM. There were 36 in attendance representing the pulmonary, critical care, sleep, pathology and radiology communities. Dinner was sponsored by Accredo Health Group. A brief discussion was held of plans to have the December 2013 meeting in Tucson on a weekend as p...

  6. Hit from both sides: tracking industrial and volcanic plumes in Mexico City with surface measurements and OMI SO2 retrievals during the MILAGRO field campaign

    Directory of Open Access Journals (Sweden)

    L. T. Molina

    2009-12-01

    Full Text Available Large sulfur dioxide plumes were measured in the Mexico City Metropolitan Area (MCMA during the MILAGRO field campaign. This paper seeks to identify the sources of these plumes and the meteorological processes that affect their dispersion in a complex mountain basin. Surface measurements of SO2 and winds are analysed in combination with radar wind profiler data to identify transport directions. Satellite retrievals of vertical SO2 columns from the Ozone Monitoring Instrument (OMI reveal the dispersion from both the Tula industrial complex and the Popocatepetl volcano. Oversampling the OMI swath data to a fine grid (3 by 3 km and averaging over the field campaign yielded a high resolution image of the average plume transport. Numerical simulations are used to identify possible transport scenarios. The analysis suggests that both Tula and Popocatepetl contribute to SO2 levels in the MCMA, sometimes on the same day due to strong vertical wind shear. During the field campaign, model estimates suggest that the volcano accounts for about one tenth of the SO2 in the MCMA, with a roughly equal split for the rest between urban sources and the Tula industrial complex. The evaluation of simulations with known sources and pollutants suggests that the combination of observations and meteorological models will be useful in identifying sources and transport processes of other plumes observed during MILAGRO.

  7. Potential application of the Scintrex CG-3M gravimeter for monitoring volcanic activity: results of field trials on Mt. Etna, Sicily

    Science.gov (United States)

    Budetta, G.; Carbone, D.

    1997-04-01

    A series of field trials have been conducted for 11 months on and around Mt. Etna (Sicily) to test the performance of the new automated Scintrex CG-3M gravimeter on active volcanoes. The results show that the data from the CG-3M compare favourably with those from the traditionally employed LaCoste and Romberg (L&R) model D gravimeter. Under severe field conditions the Scintrex meter, because of its greater ruggedness and fully automated capabilities, yields results superior to those from the L&R D models. Repeated measurements (568) in a wide range of field conditions yielded errors in Δ g between stations of ± 3.5 to ± 4.4 μGal. Our tests also showed that both the strong drift in stationary conditions (~ 1 mGald -1) and changes of the instrumental calibration factor with time (whose rate decreased from 6 to 1 ppmd -1 during the 11-month study) can be reduced by regular checks to acceptable standards. Thus, (a) using experimental data, the instrumental drift was forecasted and corrected (by the real-time automatical compensator of the instrument) to within about 20 μGald -1, and (b) using the measurements along an 18-station profile on Mt. Etna (total gravity range ≈ 300 mGal), and an 80-km-long calibration line away from the volcano (six stations, total gravity range = 365 mGal) the changes of the calibration factor were determined and corrected to within about 30 ppm.

  8. Pahoehoe-a‧a transitions in the lava flow fields of the western Deccan Traps, India-implications for emplacement dynamics, flood basalt architecture and volcanic stratigraphy

    Science.gov (United States)

    Duraiswami, Raymond A.; Gadpallu, Purva; Shaikh, Tahira N.; Cardin, Neha

    2014-04-01

    Unlike pahoehoe, documentation of true a‧a lavas from a modern volcanological perspective is a relatively recent phenomenon in the Deccan Trap (e.g. Brown et al., 2011, Bull. Volcanol. 73(6): 737-752) as most lava flows previously considered to be a‧a (e.g. GSI, 1998) have been shown to be transitional (e.g. Rajarao et al., 1978, Geol. Soc. India Mem. 43: 401-414; Duraiswami et al., 2008 J. Volcanol. Geothermal. Res. 177: 822-836). In this paper we demonstrate the co-existence of autobrecciation products such as slabby pahoehoe, rubbly pahoehoe and a‧a in scattered outcrops within the dominantly pahoehoe flow fields. Although volumetrically low in number, the pattern of occurrence of the brecciating lobes alongside intact ones suggests that these might have formed in individual lobes along marginal branches and terminal parts of compound flow fields. Complete transitions from typical pahoehoe to 'a‧a lava flow morphologies are seen on length scales of 100-1000 m within road and sea-cliff sections near Uruli and Rajpuri. We consider the complex interplay between local increase in the lava supply rates due to storage or temporary stoppage, local increase in paleo-slope, rapid cooling and localized increase in the strain rates especially in the middle and terminal parts of the compound flow field responsible for the transitional morphologies. Such transitions are seen in the Thakurwadi-, Bushe- and Poladpur Formation in the western Deccan Traps. These are similar to pahoehoe-a‧a transitions seen in Cenozoic long lava flows (Undara ˜160 km, Toomba ˜120 km, Kinrara ˜55 km) from north Queensland, Australia and Recent (1859) eruption of Mauna Loa, Hawaii (a‧a lava flow ˜51 km) suggesting that flow fields with transitional tendencies cannot travel great lengths despite strong channelisation. If these observations are true, then it arguably limits long distance flow of Deccan Traps lavas to Rajahmundry suggesting polycentric eruptions at ˜65 Ma in

  9. California's Vulnerability to Volcanic Hazards: What's at Risk?

    Science.gov (United States)

    Mangan, M.; Wood, N. J.; Dinitz, L.

    2015-12-01

    California is a leader in comprehensive planning for devastating earthquakes, landslides, floods, and tsunamis. Far less attention, however, has focused on the potentially devastating impact of volcanic eruptions, despite the fact that they occur in the State about as frequently as the largest earthquakes on the San Andreas Fault Zone. At least 10 eruptions have occurred in the past 1,000 years—most recently in northern California (Lassen Peak 1914 to 1917)—and future volcanic eruptions are inevitable. The likelihood of renewed volcanism in California is about one in a few hundred to one in a few thousand annually. Eight young volcanoes, ranked as Moderate to Very High Threat [1] are dispersed throughout the State. Partially molten rock (magma) resides beneath at least seven of these—Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, Long Valley Volcanic Region, Coso Volcanic Field, and Salton Buttes— causing earthquakes, toxic gas emissions, hydrothermal activity, and (or) ground deformation. Understanding the hazards and identifying what is at risk are the first steps in building community resilience to volcanic disasters. This study, prepared in collaboration with the State of California Governor's Office of Emergency Management and the California Geological Survey, provides a broad perspective on the State's exposure to volcano hazards by integrating mapped volcano hazard zones with geospatial data on at-risk populations, infrastructure, and resources. The study reveals that ~ 16 million acres fall within California's volcano hazard zones, along with ~ 190 thousand permanent and 22 million transitory populations. Additionally, far-field disruption to key water delivery systems, agriculture, utilities, and air traffic is likely. Further site- and sector-specific analyses will lead to improved hazard mitigation efforts and more effective disaster response and recovery. [1] "Volcanic Threat and Monitoring Capabilities

  10. DECOVALEX-THMC Task D: Long-Term Permeability/Porosity Changes inthe EDZ and Near Field due to THM and THC Processes in Volcanic andCrystaline-Bentonite Systems, Status Report October 2005

    Energy Technology Data Exchange (ETDEWEB)

    Birkholzer, J.; Rutqvist, J.; Sonnenthal, E.; Barr, D.

    2005-11-01

    The DECOVALEX project is an international cooperativeproject initiated by SKI, the Swedish Nuclear Power Inspectorate, withparticipation of about 10 international organizations. The name DECOVALEXstands for DEvelopment of COupled models and their VALidation againstExperiments. The general goal of this project is to encouragemultidisciplinary interactive and cooperative research on modelingcoupled processes in geologic formations in support of the performanceassessment for underground storage of radioactive waste. Three multi-yearproject stages of DECOVALEX have been completed in the past decade,mainly focusing on coupled thermal-hydrological-mechanicalprocesses.Currently, a fourth three-year project stage of DECOVALEX isunder way, referred to as DECOVALEX-THMC. THMC stands for Thermal,Hydrological, Mechanical, and Chemical processes. The new project stageaims at expanding the traditional geomechanical scope of the previousDECOVALEX project stages by incorporating geochemical processes importantfor repository performance. The U.S. Department of Energy (DOE) leadsTask D of the new DECOVALEX phase, entitled "Long-termPermeability/Porosity Changes in the EDZ and Near Field due to THC andTHM Processes for Volcanic and Crystalline-Bentonite Systems." In itsleadership role for Task D, DOE coordinates and sets the direction forthe cooperative research activities of the international research teamsengaged in Task D.

  11. Views from Inside a Pediatric Clinic: How Arizona's Political Climate Has Impacted Arizona's Youngest Latino Learners

    Science.gov (United States)

    Jimenez-Silva, Margarita; Cheatham, Gregory A.; Gomez, Laura

    2013-01-01

    It is critical that we examine impacts that recent immigration policies such as SB1070 are having on Arizona's youngest Latino learners.The large number of Latinos under the age of five, and the impact that this upcoming generation of Latinos will have on all aspects of life in Arizona merits a closer look. In this qualitative study, we examined…

  12. 77 FR 25741 - Notice of Inventory Completion: Arizona State Museum, University of Arizona, Tucson, AZ

    Science.gov (United States)

    2012-05-01

    ... Gila Pueblo Foundation closed and the collections were donated to the Arizona State Museum. No known... types, and other items of material culture are consistent with the Hohokam archeological tradition and... Gila Pueblo Foundation closed and the collections were donated to the Arizona State Museum. No known...

  13. Backprojection of volcanic tremor

    Science.gov (United States)

    Haney, Matthew M.

    2014-01-01

    Backprojection has become a powerful tool for imaging the rupture process of global earthquakes. We demonstrate the ability of backprojection to illuminate and track volcanic sources as well. We apply the method to the seismic network from Okmok Volcano, Alaska, at the time of an escalation in tremor during the 2008 eruption. Although we are able to focus the wavefield close to the location of the active cone, the network array response lacks sufficient resolution to reveal kilometer-scale changes in tremor location. By deconvolving the response in successive backprojection images, we enhance resolution and find that the tremor source moved toward an intracaldera lake prior to its escalation. The increased tremor therefore resulted from magma-water interaction, in agreement with the overall phreatomagmatic character of the eruption. Imaging of eruption tremor shows that time reversal methods, such as backprojection, can provide new insights into the temporal evolution of volcanic sources.

  14. Volcanic eruptions on Io

    Science.gov (United States)

    Strom, R. G.; Schneider, N. M.; Terrile, R. J.; Cook, A. F.; Hansen, C.

    1981-09-01

    Nine eruption plumes which were observed during the Voyager 1 encounter with Io are discussed. During the Voyager 2 encounter, four months later, eight of the eruptions were still active although the largest became inactive sometime between the two encounters. Plumes range in height from 60 to over 300 km with corresponding ejection velocities of 0.5 to 1.0 km/s and plume sources are located on several plains and consist of fissures or calderas. The shape and brightness distribution together with the pattern of the surface deposition on a plume 3 is simulated by a ballistic model with a constant ejection velocity of 0.5 km/s and ejection angles which vary from 0-55 deg. The distribution of active and recent eruptions is concentrated in the equatorial regions and indicates that volcanic activity is more frequent and intense in the equatorial regions than in the polar regions. Due to the geologic setting of certain plume sources and large reservoirs of volatiles required for the active eruptions, it is concluded that sulfur volcanism rather than silicate volcanism is the most likely driving mechanism for the eruption plumes.

  15. Paleomagnetic studies of volcanic rocks in Siberia and sedimentary rocks in Southern Alberta: From long-term geomagnetic field variations to age determinations

    Science.gov (United States)

    Blanco Acuna, Dunia

    Paleomagnetism is a fundamental tool to understand the ancient variations of Earth's magnetic field through time. Important applications to geochronology and paleography come from interpreting the variations of the planetary magnetic vector. This dissertation explores the different applications of paleomagnetism to uncover important characteristics of the paleointensity magnetic field during the Permo-Triassic boundary and the nature of the apparent polar wander path (APWP) of Siberia, and to create geochronological frameworks for kimberlites in the Siberian platform and for sediments at the Western Canada Sedimentary Basin. Detailed absolute paleointensity measurements from Permo-Triassic sills at the Siberian platform are studied to determine the existence of a low dipole field, which has been previously reported in the area. We found a mean virtual dipolar moment value of 6.01 +/- 1.45 x 1022 Am 2 which is over 50% higher than the results previously obtained by other authors. Diamondiferous kimberlite pipes are exposed across the north-central part of the Siberian platform. The age of the magmatic activity cannot be clearly determined from isotopic age data---this is the reason why new paleomagnetic poles from four kimberlite pipes are obtained to study their paleomagnetic age. On the basis of a comparison with the Siberian APWP, we estimate the age of the kimberlite magmatism. The acquired paleomagnetic ages span from the Early Silurian to the Middle Late Jurassic. Magnetostratigraphic analysis is used as a dating tool on three deep drilling cores that penetrate Santonian-Campanian strata in southern Alberta, Canada. Chrons 34n and 33r are clearly identified from the studied sections---providing a high-resolution age boundary that creates new age boundaries between adjacent stratigraphic units. In addition, normal polarity zones are observed within C33r, previously described as reverse polarity over its entire length. Siberian APWP contains long unresolved

  16. Project Title: Geothermal Play Fairway Analysis of Potential Geothermal Resources in NE California, NW Nevada, and Southern Oregon: A Transition between Extension$-$Hosted and Volcanically$-$Hosted Geothermal Fields

    Energy Technology Data Exchange (ETDEWEB)

    McClain, James S. [Univ. of California, Davis, CA (United States). Dept. of; Dobson, Patrick [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Glassley, William [Univ. of California, Davis, CA (United States). Dept. of Earth and Planetary Sciences; Schiffman, Peter [Univ. of California, Davis, CA (United States). Dept. of Earth and Planetary Sciences; Zierenberg, Robert [Univ. of California, Davis, CA (United States). Dept. of Earth and Planetary Sciences; Zhang, Yingqi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Conrad, Mark [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Siler, Drew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gasperikova, Erika [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Spycher, Nicolas F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-09-30

    Final report for the UCD-LBNL effort to apply Geothermal Play Fairway Analysis to a transition zone between a volcanically-hosted and extensionally-hosted geothermal. The project focusses on the geothermal resources in northeastern California.

  17. Chapter 2: Beginning of water studies in the Central Arizona Highlands

    Science.gov (United States)

    Gerald J. Gottfried; Leonard F. DeBano; Malchus B. Baker

    1999-01-01

    Water has been recognized as an important resource in central Arizona and has affected populations occupying the Salt River Valley for centuries. Water related activities have been documented since about 200 before the common era, when Hohokam Indians settled the Valley and constructed canals to irrigate their fields. Europeans began to settle in the Phoenix area in...

  18. Optics education through the Arizona Galileoscope program

    Science.gov (United States)

    Pompea, Stephen M.; Sparks, Robert T.; Walker, Constance E.; Dokter, Erin F. C.

    2012-10-01

    The National Optical Astronomy Observatory, in collaboration with Science Foundation Arizona and the Arizona public schools, has initiated a program of optics education that has been implemented in the Arizona cities of Flagstaff, Yuma, and Safford. A program is planned for Globe, Arizona and several other locations. The program is aimed at 5th grade teachers and students. It relies on NOAO-developed optics teaching kits designed around the Galileoscope student telescope kits. The program is designed to reach every 5th grade teacher and every 5th grade student in each city. Professional development is provided for the teachers using the NOAO-developed "Teaching with Telescopes" optics teaching kits which are given to each teacher. Each 5th grade student is part of a team building a Galileoscope and receives additional training on how to use the Galileoscope during the day or night. At the end of the training period a large star party is held for all of the students, their families, and their friends. The program is evaluated through the University of Arizona. This model has been successfully implemented during the past two years and we are exploring national replication. This program provides a cost-effective way to inject optics into the schools in an attractive, citywide program model. The talk will discuss the model in detail and some of the mistakes we have made as we have tested the model.

  19. Io Eclipse/Volcanic Eruption

    Science.gov (United States)

    1997-01-01

    This image was acquired while Io was in eclipse (in Jupiter's shadow) during Galileo's eighth orbit, and reveals several dynamic processes. The most intense features are red, while glows of lesser intensity are yellow or green, and very faint glows appear blue in this color-coded image. The small red or yellow spots mark the sites of high-temperature magma erupting onto the surface in lava flows or lava lakes.This image reveals a field of bright spots near Io's sub-Jupiter point (right-hand side of image). The sub-Jupiter hemisphere always faces Jupiter just as the Moon's nearside always faces Earth. There are extended diffuse glows on the equatorial limbs or edges of the planet (right and left sides). The glow on the left is over the active volcanic plume Prometheus, but whereas Prometheus appears to be 75 kilometers (46.6 miles) high in reflected light, here the diffuse glow extends about 800 kilometers (497 miles) from Io's limb. This extended glow indicates that gas or small particles reach much greater heights than the dense inner plume. The diffuse glow on the right side reaches a height of 400 kilometers (249 miles), and includes a prominence with a plume-like shape. However, no volcanic plume has been seen at this location in reflected light. This type of observation is revealing the relationships between Io's volcanism, atmosphere and exosphere.Taken on May 6, 1997, north is toward the top. The image was taken with the clear filter of the solid state imaging (CCD) system on NASA's Galileo spacecraft at a range of 1.8 million kilometers (1.1 million miles).The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational

  20. Prevention of Catastrophic Volcanic Eruptions

    OpenAIRE

    Fujii, Yoshiaki; Kodama, Jun-ichi; Fukuda, Daisuke; Dassanayake, Abn

    2017-01-01

    Giant volcanic eruptions emit sulphate aerosols as well as volcanic ash. Needless to say that volcanic ash causes significant damage to the environment and human at large. However, the aerosols are even worse. They reach the Stratosphere and stay there for months to years reflecting insolation. As a result, air temperature at the Earth's surfaces drops. Even a slight temperature drop may cause severe food shortage. Yellowstone supervolcano, for example, can even make human in the Northern Hem...

  1. The impact of Arizona Highways Magazine's facebook page.

    Science.gov (United States)

    2014-02-01

    This project examined the relationship between use of the Arizona Highways magazine (AHM) Facebook Page and the decision to : travel to or within Arizona. Key purposes were to: (1) provide a thorough understanding of AHM Facebook Page users, includin...

  2. Volcanic Ash Nephelometer Probe Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced dropsondes that could effectively be guided through atmospheric regions of interest such as volcanic plumes may enable unprecedented observations of...

  3. Halogen Chemistry in Volcanic Plumes (Invited)

    Science.gov (United States)

    Roberts, Tjarda

    2017-04-01

    only partially constrained by available observations. Reactions on aerosol are a key driver of the chemistry and are affected by uncertainties in both the HOBr reactive uptake coefficient and the aerosol surface area. Recent work has explored the reactive uptake of HOBr on sulfate-rich aerosol, whilst field-measurements at Mt Etna have aimed to quantify the size-resolved primary aerosol emission, towards improving model representations of this highly non-linear volcanic plume halogen chemistry.

  4. March 2014 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-04-01

    Full Text Available No abstract available. Article truncated after 150 words. The March 2014 Arizona Thoracic Society meeting was a special meeting. In conjunction with the Valley Fever Center for Excellence and the Arizona Respiratory Center the Eighteenth Annual Farness Lecture was held in the Sonntag Pavilion at St. Joseph's Hospital at 6 PM on Friday, April 4, 2014. The guest speaker was Antonio "Tony" Catanzaro, MD from the University of California San Diego and current president of the Cocci Study Group. There were 57 in attendance representing the pulmonary, critical care, sleep, and infectious disease communities. After opening remarks by Arizona Thoracic Society president, Lewis Wesselius (a former fellow under Dr. Catanzaro at UCSD, John Galgiani, director of the Valley Fever Center for Excellence, gave a brief history of the Farness lecture before introducing Dr. Catanzaro. The lecture is named for Orin J. Farness, a Tucson physician, who was the first to report culture positive coccidioidomycosis (cocci or Valley Fever. ...

  5. Helping Students Enter the Health Professions in Arizona.

    Science.gov (United States)

    Hernandez, Aleena; Parker, Myra; Lewis, John; Roubideaux, Yvette

    2003-01-01

    The University of Arizona and the Inter Tribal Council of Arizona collaborate on a program to increase the number of American Indian students who enter the health professions and eventually serve communities in Arizona. The council conducts outreach, needs assessments, and health career forums. The university provides students with counseling;…

  6. Report list Arizona's oil, gas potential

    Science.gov (United States)

    Rauzi, S.L.

    2001-01-01

    This article is a summary of Arizona geological survey circular 29, which addresses the petroleum geology of Arizona, USA. Eight areas have been identified with fair to excellent oil and gas potential, and some Tertiary basins have evidence of source or reservoir rocks. The following are considered here: production history, lands status and services, regulation and permitting, petroleum geology, hydrocarbon indications, and areas with hydrocarbon potential and their petroleum geology and characteristics. The full report contains detailed figures of each of these basin areas, a descriptive tabulation of seeps and petroliferous rocks and extensive references.

  7. Preliminary bedrock and surficial geologic map of the west half of the Sanders 30' x 60' quadrangle, Navajo and Apache Counties, northern Arizona

    Science.gov (United States)

    Amoroso, Lee; Priest, Susan S.; Hiza-Redsteer, Margaret

    2014-01-01

    The bedrock and surficial geologic map of the west half of the Sanders 30' x 60' quadrangle was completed in a cooperative effort of the U.S. Geological Survey (USGS) and the Navajo Nation to provide regional geologic information for management and planning officials. This report provides baseline geologic information that will be useful in future studies of groundwater and surface water resources, geologic hazards, and the distribution of soils and plants. The west half of the Sanders quadrangle encompasses approximately 2,509 km2 (980 mi2) within Navajo and Apache Counties of northern Arizona and is bounded by lat 35°30' to 35° N., long 109°30' to 110° W. The majority of the land within the map area lies within the Navajo Nation. South of the Navajo Nation, private and State lands form a checkerboard pattern east and west of Petrified Forest National Park. In the west half of the Sanders quadrangle, Mesozoic bedrock is nearly flat lying except near folds. A shallow Cenozoic erosional basin that developed about 20 Ma in the western part of the map area cut across late Paleozoic and Mesozoic rocks that were subsequently filled with flat-lying Miocene and Pliocene mudstone and argillaceous sandstone and fluvial sediments of the Bidahochi Formation and associated volcanic rocks of the Hopi Buttes volcanic field. The Bidahochi rocks are capped by Pliocene(?) and Pleistocene fluvial sediments and Quaternary eolian and alluvial deposits. Erosion along northeast-southwest-oriented drainages have exposed elongated ridges of Bidahochi Formation and basin-fill deposits that are exposed through shallow eolian cover of similarly oriented longitudinal dunes. Stokes (1964) concluded that the accumulation of longitudinal sand bodies and the development of confined parallel drainages are simultaneous processes resulting in parallel sets of drainages and ridges oriented along the prevailing southwest wind direction on the southern Colorado Plateau.

  8. Lidar detection of carbon dioxide in volcanic plumes

    Science.gov (United States)

    Fiorani, Luca; Santoro, Simone; Parracino, Stefano; Maio, Giovanni; Del Franco, Mario; Aiuppa, Alessandro

    2015-06-01

    Volcanic gases give information on magmatic processes. In particular, anomalous releases of carbon dioxide precede volcanic eruptions. Up to now, this gas has been measured in volcanic plumes with conventional measurements that imply the severe risks of local sampling and can last many hours. For these reasons and for the great advantages of laser sensing, the thorough development of volcanic lidar has been undertaken at the Diagnostics and Metrology Laboratory (UTAPRAD-DIM) of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). In fact, lidar profiling allows one to scan remotely volcanic plumes in a fast and continuous way, and with high spatial and temporal resolution. Two differential absorption lidar instruments will be presented in this paper: BILLI (BrIdge voLcanic LIdar), based on injection seeded Nd:YAG laser, double grating dye laser, difference frequency mixing (DFM) and optical parametric amplifier (OPA), and VULLI (VULcamed Lidar), based on injection seeded Nd:YAG laser and optical parametric oscillator (OPO). The first one is funded by the ERC (European Research Council) project BRIDGE and the second one by the ERDF (European Regional Development Fund) project VULCAMED. While VULLI has not yet been tested in a volcanic site, BILLI scanned the gas emitted by Pozzuoli Solfatara (Campi Flegrei volcanic area, Naples, Italy) during a field campaign carried out from 13 to 17 October 2014. Carbon dioxide concentration maps were retrieved remotely in few minutes in the crater area. Lidar measurements were in good agreement with well-established techniques, based on different operating principles. To our knowledge, it is the first time that carbon dioxide in a volcanic plume is retrieved by lidar, representing the first direct measurement of this kind ever performed on an active volcano and showing the high potential of laser remote sensing in geophysical research.

  9. Amazonian volcanism inside Valles Marineris on Mars

    Science.gov (United States)

    Brož, Petr; Hauber, Ernst; Wray, James J.; Michael, Gregory

    2017-09-01

    The giant trough system of Valles Marineris is one of the most spectacular landforms on Mars, yet its origin is still unclear. Although often referred to as a rift, it also shows some characteristics that are indicative of collapse processes. For decades, one of the major open questions was whether volcanism was active inside the Valles Marineris. Here we present evidence for a volcanic field on the floor of the deepest trough of Valles Marineris, Coprates Chasma. More than 130 individual edifices resemble scoria and tuff cones, and are associated with units that are interpreted as lava flows. Crater counts indicate that the volcanic field was emplaced sometime between ∼0.4 Ga and ∼0.2 Ga. The spatial distribution of the cones displays a control by trough-parallel subsurface structures, suggesting magma ascent in feeder dikes along trough-bounding normal faults. Spectral data reveal an opaline-silica-rich unit associated with at least one of the cones, indicative of hydrothermal processes. Our results point to magma-water interaction, an environment of astrobiological interest, perhaps associated with late-stage activity in the evolution of Valles Marineris, and suggest that the floor of Coprates Chasma is promising target for the in situ exploration of Mars.

  10. 78 FR 21412 - Notice of Intent To Repatriate a Cultural Item: Arizona State Museum, University of Arizona...

    Science.gov (United States)

    2013-04-10

    ... National Park Service Notice of Intent To Repatriate a Cultural Item: Arizona State Museum, University of... Museum, University of Arizona, in consultation with the appropriate Indian tribes or Native Hawaiian... the Arizona State Museum. If no additional claimants come forward, transfer of control of the cultural...

  11. Volcanic sulfur dioxide index and volcanic explosivity index inferred from eruptive volume of volcanoes in Jeju Island, Korea: application to volcanic hazard mitigation

    Science.gov (United States)

    Ko, Bokyun; Yun, Sung-Hyo

    2016-04-01

    Jeju Island located in the southwestern part of Korea Peninsula is a volcanic island composed of lavaflows, pyroclasts, and around 450 monogenetic volcanoes. The volcanic activity of the island commenced with phreatomagmatic eruptions under subaqueous condition ca. 1.8-2.0 Ma and lasted until ca. 1,000 year BP. For evaluating volcanic activity of the most recently erupted volcanoes with reported age, volcanic explosivity index (VEI) and volcanic sulfur dioxide index (VSI) of three volcanoes (Ilchulbong tuff cone, Songaksan tuff ring, and Biyangdo scoria cone) are inferred from their eruptive volumes. The quantity of eruptive materials such as tuff, lavaflow, scoria, and so on, is calculated using a model developed in Auckland Volcanic Field which has similar volcanic setting to the island. The eruptive volumes of them are 11,911,534 m3, 24,987,557 m3, and 9,652,025 m3, which correspond to VEI of 3, 3, and 2, respectively. According to the correlation between VEI and VSI, the average quantity of SO2 emission during an eruption with VEI of 3 is 2-8 × 103 kiloton considering that the island was formed under intraplate tectonic setting. Jeju Island was regarded as an extinct volcano, however, several studies have recently reported some volcanic eruption ages within 10,000 year BP owing to the development in age dating technique. Thus, the island is a dormant volcano potentially implying high probability to erupt again in the future. The volcanoes might have explosive eruptions (vulcanian to plinian) with the possibility that SO2 emitted by the eruption reaches stratosphere causing climate change due to backscattering incoming solar radiation, increase in cloud reflectivity, etc. Consequently, recommencement of volcanic eruption in the island is able to result in serious volcanic hazard and this study provides fundamental and important data for volcanic hazard mitigation of East Asia as well as the island. ACKNOWLEDGMENTS: This research was supported by a grant [MPSS

  12. geochemistry of the potassic basalts from the bufumbira volcanic

    African Journals Online (AJOL)

    Mgina

    volcanic fields within the western branch of the East African rift system. The rocks consist of silica undersaturated and ..... Plot of total alkalis (K2O + N2O wt%) versus SiO2 wt% of the various rocks of the. Bufumbira field (Cox et al. 1979). The Le Maitre (1989) plot (Fig. 8) clusters most of the mafic rocks between the basanite.

  13. Amphibian acoustic data from the Arizona 1, Pinenut, and Canyon breccia pipe uranium mines in Arizona

    Science.gov (United States)

    Hinck, Jo E.; Hossack, Blake R.; Honeycutt, Richard

    2017-01-01

    The data consists of a summary of amphibian acoustic recordings at Canyon, Arizona 1, and Pinenut mines near the Grand Canyon. USGS is currently conducting biological surveys associated with uranium mines on federal lands in Arizona. These surveys include determining the composition of the local amphibian community. Original raw acoustic recordings used to create this summary data table are archived at Columbia Environmental Research Center.

  14. The Oldest Known Caldera Associated with the Yellowstone Hotspot: New Geologic Mapping, Geochemistry, and 40Ar/39Ar Geochronology for the Northern McDermitt Volcanic Field, Northern Nevada and Southeastern Oregon

    Science.gov (United States)

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

    2015-12-01

    McDermitt Volcanic Field (MVF) of Nevada and Oregon is one of three major caldera centers associated with Mid-Miocene Steens/Columbia River flood basalts. Pioneering geologic mapping of MVF by Rytuba and McKee (1984) and subsequent work established four main ignimbrites within the field. Our new 40Ar/39Ar ages (FCT=28.02 Ma) are 16.41±0.02 (±2σ) Ma for Tuff of Oregon Canyon, 16.35±0.04 Ma for Tuff of Trout Creek Mountains, 16.30±0.04 Ma for Tuff of Long Ridge, and 15.56±0.08 Ma for Tuff of Whitehorse Creek. We have mapped two previously unrecognized overlapping calderas that we interpret as sources for Tuff of Oregon Canyon and Tuff of Trout Creek. These ~20-km diameter calderas lie north of the well-known McDermitt Caldera; a smaller 7-km caldera that formed on eruption of the Tuff of Whitehorse Creek is nested within them. Argon ages and geochemistry of alkali rhyolite lava domes in the northern MVF define two populations: ~16.6-16.3 Ma associated with the newly recognized calderas, and ~15.5-15.3 Ma outlining the margins of the younger Whitehorse Caldera. Consistent with both ignimbrites erupting from the same evolving magma system, the high-silica alkali rhyolite Tuff of Oregon Canyon lies on compositional trends defined by the Tuff of Trout Creek, which is zoned from a moderately crystal-rich high-silica alkali rhyolite to a strongly porphyritic low-silica alkali rhyolite. They both are distinguished from the Tuff of Long Ridge from McDermitt Caldera by their higher Zr/Rb, and relatively high FeO* concentrations distinguish all MVF ignimbrites from ignimbrites from the nearby High Rock Caldera Complex, where the oldest caldera formed on eruption of the Idaho Canyon Tuff at 16.38±0.02 Ma (Coble and Mahood, in review). The Tuff of Trout Creek rests conformably on the Tuff of Oregon Canyon west and southwest of the calderas, where they overlie a thick stack of Steens Basalt lavas. To the east and southeast the two ignimbrites are separated by as much as

  15. Ar-Ar Phlogopite Geochronology of the Navajo Volcanic Field and the Ship Rock Diatreme of Northwest New Mexico Define a 1.4 Ma Pulse of Potassic Magmatism

    Science.gov (United States)

    Nybo, J. P.; McIntosh, W. C.; Semken, S. C.

    2011-12-01

    Newly acquired Ar-Ar phlogopite ages indicate a brief but widespread pulse of magmatism at 25.9 to 24.5 Ma in Navajo Volcanic Field (NVF). Covering approximately 30,000 km2 of the Four Corners region in the southwestern US and including the Ship Rock diatreme, the NVF forms approximately 100 diatremes, plugs, dikes, and occasional sills and maars. Petrographically the field is dominated by minette and serpentinized ultramafic microbreccia though katungite dikes occur in localized areas. Published K-Ar ages from the NVF range from 33.9 to 19.4 Ma1,2. Published Ar-Ar ages are sparse but a 25.05 Ma3 age in the Chuska Mountains and a 6.7 Ma4 age in SW Colorado have been reported. Phlogopite separates of six dikes from the Shiprock diatreme along with two dikes and two plugs from other locations throughout the NVF were analyzed in this study by the Ar-Ar method using CO2 laser and resistance furnace incremental heating. The resulting age spectra were generally flat and a selection of the most precise ages range from 25.9 ± 0.1 Ma at Todilto Park, AZ to 24.4 ± 0.1 Ma at Ship Rock, NM. The selected samples spatially represent the full breadth of the NVF with four pulses of magmatism interpreted at 25.9 Ma, 25.4 Ma, 24.9 Ma, and 24.5 Ma, altogether spanning a range 1.4 Ma. The narrow range of ages found in this study contrasts with the much wider range of published ages implying the bulk of the NVF was emplaced by a short pulse of widespread magmatism rather than series of temporally spaced eruptions. Additional geochronology will assess whether additional eruptive pulses occurred in the NVF. 1Laughlin, AW, et al, EPSL 76, 1986. 2Roden, MF, et al, EPSL 43, 1979. 3Cather, SM, et al, NMGS Guidebook 54, 2003. 4Gonzalez, DA, et al, NMGS Guidbook 61, 2010.

  16. Why does the Size of the Laacher See Magma Chamber and its Caldera Size not go together? - New Findings with regard to Active Tectonics in the East Eifel Volcanic Field

    Science.gov (United States)

    Schreiber, Ulrich; Berberich, Gabriele

    2013-04-01

    . 2002). Our research findings suggest that due to the slow movement rates of active tectonic faults, an estimated 18 km³ magma chamber within the brittle fracture section of the earth's crust beneath the Laacher See (v. d. Bogaard & Schmincke 1984) cannot be confirmed yet. Another discrepancy is given by a comparison of modeling of caldera evolution (Acocella 2007) with the Laacher See Caldera formation. The Laacher See caldera has a volume of 0.5 km³ with regard to the pre-eruptive surface (Viereck & v.d. Bogaard 1986). According to v. d. Bogaard & Schmincke (1984) a volume of 6.3 km³ dry rock equivalent of lava and basic rock was erupted. This magnitude is contradictory to the calculated 0.5 km³ volume of the Laacher See caldera. A volume compensation of approx. 6 km³ which could have prevented a further subsidence of the magma chamber cannot be a scientific possible explanation. This hypothesis is strengthened by performed sonar recordings of the post-eruptive Laacher See sediment layers which do not show any displacements that might indicate a doming caused by magma. Estimations of the erupted tephra volume provided the basis for the calculation of the size of the Laacher See magma chamber (v.d. Bogaard 1983), but there is no statistical significant data set with regard to spatial distribution of the erupted tephra amount. Our findings show an overestimation of the tephra thickness in published isopach maps of the Westerwald. Therefore, an order of magnitude smaller magma chamber stretched over a longer vertical crustal section can help to better match the given tectonic movement rates and the size of the caldera. To estimate the future development of the East Eifel volcanic field, a good knowledge of the active tectonics is an absolute prerequisite. Along the "Laacher See Strike-slip Fault", an area of intensive micro-seismicity and a new seismically active zone with local magnitudes up to 4 has developed over the last 40 years (Hinzen 2003). In the last

  17. Return of the Tarahumara frog to Arizona

    Science.gov (United States)

    James C. Rorabaugh; Stephen F. Hale; Michael J. Sredl; Craig Ivanyi

    2005-01-01

    The last wild Tarahumara frog (Rana tarahumarae) in Arizona was found dead in Big Casa Blanca Canyon, Santa Rita Mountains, in May 1983. However, the species is still well represented in the majority of its range in the northern Sierra Madre Occidental and adjacent Sky Islands of Sonora and Chihuahua. Plans to re-establish R. tarahumarae...

  18. 40 CFR 131.31 - Arizona.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Arizona. 131.31 Section 131.31 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS WATER QUALITY STANDARDS..., 3033 North Central Ave., Phoenix, AZ 85012): COLORADO MAIN STEM RIVER BASIN: Hualapai Wash MIDDLE GILA...

  19. The Political Spectacle of Arizona's Proposition 203

    Science.gov (United States)

    Wright, Wayne E.

    2005-01-01

    Arizona's Proposition 203 places restrictions on bilingual and English-as-a-second-language programs and essentiality mandates English-only education for English language learners (ELLs). This article provides an analysis of this initiative and the wide variations in its interpretation and implementation. Data sources include official policy and…

  20. Smoking Policies of Secondary Schools in Arizona.

    Science.gov (United States)

    Rashak, Nancy E.; And Others

    1986-01-01

    Smoking policies and programs of accredited secondary schools in Arizona were analyzed to discover the existence of written smoking policies, how students, faculty, and visitors were informed of the policy, the extent to which smoking was permitted on school grounds, availability of smoking cessation programs and the inclusion of health education…

  1. Tracking rare orchids (Orchidaceae) in Arizona

    Science.gov (United States)

    Ronald A. Coleman

    2001-01-01

    Twenty-six native orchid species occur in Arizona, and 14 are considered rare with fewer than 100 occurrences in the state. The author is conducting three studies covering four of the wild orchids: Stenorrhynchos michuacanum, Hexalectris revoluta, Malaxis porphyry, and M. tenuis. The studies are ongoing so only interim results are available. Interim results indicate...

  2. August 2014 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-08-01

    Full Text Available No abstract available. Article truncated after 150 words. The August 2014 Arizona Thoracic Society meeting was held on Wednesday, 8/27/14 at Scottsdale Shea Hospital beginning at 6:30 PM. This was a dinner meeting with case presentations. There were about 30 in attendance representing the pulmonary, critical care, sleep and radiology communities. A presentation was given by Julie Reid of the American Lung Association in Arizona on their Lung Force initiative. This is an initiative to make women more aware that lung cancer is the number 1 cause of cancer deaths in women. There will be a fund raising Lung Force Walk on November 15, 2014 in Phoenix. More information can be found at http://www.lungforce.org/walk-events or http://www.lung.org/associations/states/arizona/local-offices/phoenix/ or contact Julie Reid at JReid@Lung Arizona.org or (602 258-7505. A discussion was instigated by Dr. Parides on whether there is an increased risk of clinical Valley Fever in patients previously treated who begin therapy with biological therapy for rheumatoid arthritis. The ...

  3. Lights, Camera, Read! Arizona Reading Program Manual.

    Science.gov (United States)

    Arizona State Dept. of Library, Archives and Public Records, Phoenix.

    This document is the manual for the Arizona Reading Program (ARP) 2003 entitled "Lights, Camera, Read!" This theme spotlights books that were made into movies, and allows readers to appreciate favorite novels and stories that have progressed to the movie screen. The manual consists of eight sections. The Introduction includes welcome…

  4. April 2013 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2013-04-01

    Full Text Available No abstract available. Article truncated at 150 words. A dinner meeting was held on Wednesday, 4/24/2013 at Scottsdale Shea beginning at 6:30 PM. There were 13 in attendance representing the pulmonary, critical care, sleep, infectious disease, and radiology communities. Drs. Gotway and August, thoracic radiologists, were both unable to attend. Dr. Tilman Kolesch from Maricopa more than capably filled in as our radiologist. The meeting was preceded by a discussion on Pharma and the availability of physicians who accept money, including dinners, from pharmaceutical companies. The Arizona Thoracic Society is sponsored by pharmaceutical companies. Ken Knox asked if Arizona Thoracic Society meetings could be held in Tucson during July and December, the two months meetings have not been scheduled. The attendees enthusiastically endorsed this expansion of the Arizona Thoracic Society meetings. In addition, Dr. Knox wishes to sponsor a winter symposium in Tucson in collaboration with the Arizona Thoracic Society. The attendees also enthusiastically endorsed this meeting. Four …

  5. Coccidiodomycosis in Arizona 2007-2008

    Centers for Disease Control (CDC) Podcasts

    2010-10-13

    This podcast looks at the impact of Coccidioidomycosis, or Valley Fever, in Arizona in 2007 and early 2008. CDC epidemiologist Dr. Tom Chiller discusses what researchers learned about this fungal disease.  Created: 10/13/2010 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 10/27/2010.

  6. The Cambrian-Ordovician rocks of Sonora, Mexico, and southern Arizona, southwestern margin of North America (Laurentia): chapter 35

    Science.gov (United States)

    Page, William R.; Harris, Alta C.; Repetski, John E.; Derby, James R.; Fritz, R.D.; Longacre, S.A.; Morgan, W.A.; Sternbach, C.A.

    2013-01-01

    Cambrian and Ordovician shelf, platform, and basin rocks are present in Sonora, Mexico, and southern Arizona and were deposited on the southwestern continental margin of North America (Laurentia). Cambrian and Ordovician rocks in Sonora, Mexico, are mostly exposed in scattered outcrops in the northern half of the state. Their discontinuous nature results from extensive Quaternary and Tertiary surficial cover, from Tertiary and Mesozoic granitic batholiths in western Sonora, and from widespread Tertiary volcanic deposits in the Sierra Madre Occidental in eastern Sonora. Cambrian and Ordovician shelf rocks were deposited as part of the the southern miogeocline on the southwestern continental margin of North America.

  7. Promoting undergraduate involvement through the University of Arizona Astronomy Club

    Science.gov (United States)

    McGraw, Allison M.; Austin, Carmen; Noyes, Matthew; Calahan, Jenny; Lautenbach, Jennifer; Henrici, Andrew; Ryleigh Fitzpatrick, M.; Shirley, Yancy L.

    2016-01-01

    The University of Arizona Astronomy Club is devoted to undergraduate success in astronomy, physics, planetary sciences and many other related fields. The club promotes many undergraduate opportunities; research projects, participating in telescope observational runs, sponsoring conference attendance as well as several public outreach opportunities. Research projects involving exoplanet transit observations and radio observations of cold molecular clouds allow undergraduates to experience data collection, telescope operations, data reduction and research presentation. The club hosts many star parties and various other public outreach events for the Tucson, Arizona location. The club often constructs their own outreach materials and structures. The club is currently working on creating a portable planetarium to teach about the night sky on the go even on the cloudiest of nights. The club is also working on creating a binocular telescope with two 10" mirrors as a recreation of the local Large Binocular Telescope for outreach purposes as well. This is a club that strives for undergraduate activity and involvement in a range of academic and extracurricular activates, and is welcoming to all majors of all levels in hopes to spark astronomical interest.

  8. Impact of the Arizona NExSS Winter School on Interdisciplinary Knowledge and Attitudes

    Science.gov (United States)

    Huff, Cierra; Burnam-Fink, Michael; Desch, Steven; Apai, Dániel

    2018-01-01

    The Nexus for Exoplanet System Science (NExSS) is a NASA-funded research coordination network whose focus is on investigating exoplanet diversity and devising strategies for searching for life on exoplanets. The fields of exoplanets and astrobiology are inherently highly interdisciplinary. Progress in these fields demands that researchers with various scientific backgrounds understand the issues and techniques of allied fields of study, including the tools and approaches used to solve different problems, as well as their limitations.In 2016, the NExSS teams at Arizona State University (ASU) and University of Arizona (UA) hosted 32 graduate students and postdoctoral researchers from various scientific backgrounds for one week at the Arizona NExSS Winter School. To bridge the gaps between fields and promote interdisciplinarity, students participated in lessons, field trips, hands-on activities, and a capstone proposal-writing activity. To assess the impact of the School on knowledge and attitudes about other fields, we administered a pre- and post-School questionnaire designed using the Impact Analysis Method of Davis & Scalice (2015).The results show that all participants gained knowledge at the School, especially in areas outside their primary field of study. The questionnaire revealed interesting differences in attitudes as well. When asked whether the geochemistry of Earth without life is predictable, planetary scientists were more likely than average to say yes, and geologists were more likely than average to say no. Their attitudes had converged after participation in the School. These results demonstrate that the Arizona NExSS Winter School was impactful not just in the knowledge gained, but in the interdisciplinary attitudes of students.

  9. Geothermal and volcanism in west Java

    Science.gov (United States)

    Setiawan, I.; Indarto, S.; Sudarsono; Fauzi I, A.; Yuliyanti, A.; Lintjewas, L.; Alkausar, A.; Jakah

    2018-02-01

    Indonesian active volcanoes extend from Sumatra, Jawa, Bali, Lombok, Flores, North Sulawesi, and Halmahera. The volcanic arc hosts 276 volcanoes with 29 GWe of geothermal resources. Considering a wide distribution of geothermal potency, geothermal research is very important to be carried out especially to tackle high energy demand in Indonesia as an alternative energy sources aside from fossil fuel. Geothermal potency associated with volcanoes-hosted in West Java can be found in the West Java segment of Sunda Arc that is parallel with the subduction. The subduction of Indo-Australian oceanic plate beneath the Eurasian continental plate results in various volcanic products in a wide range of geochemical and mineralogical characteristics. The geochemical and mineralogical characteristics of volcanic and magmatic rocks associated with geothermal systems are ill-defined. Comprehensive study of geochemical signatures, mineralogical properties, and isotopes analysis might lead to the understanding of how large geothermal fields are found in West Java compared to ones in Central and East Java. The result can also provoke some valuable impacts on Java tectonic evolution and can suggest the key information for geothermal exploration enhancement.

  10. Oxygen isotope evolution of the Lake Owyhee volcanic field, Oregon, and implications for the low-δ18O magmatism of the Snake River Plain-Yellowstone hotspot and other low-δ18O large igneous provinces

    Science.gov (United States)

    Blum, Tyler B.; Kitajima, Kouki; Nakashima, Daisuke; Strickland, Ariel; Spicuzza, Michael J.; Valley, John W.

    2016-11-01

    The Snake River Plain-Yellowstone (SRP-Y) hotspot track represents the largest known low-δ18O igneous province; however, debate persists regarding the timing and distribution of meteoric hydrothermal alteration and subsequent melting/assimilation relative to hotspot magmatism. To further constrain alteration relations for SRP-Y low-δ18O magmatism, we present in situ δ18O and U-Pb analyses of zircon, and laser fluorination δ18O analyses of phenocrysts, from the Lake Owyhee volcanic field (LOVF) of east-central Oregon. U-Pb data place LOVF magmatism between 16.3 and 15.4 Ma, and contain no evidence for xenocrystic zircon. LOVF δ18O(Zrc) values demonstrate (1) both low-δ18O and high-δ18O caldera-forming and pre-/post-caldera magmas, (2) relative increases in δ18O between low-δ18O caldera-forming and post-caldera units, and (3) low-δ18O magmatism associated with extension of the Oregon-Idaho Graben. The new data, along with new compilations of (1) in situ zircon δ18O data for the SRP-Y, and (2) regional δ18O(WR) and δ18O(magma) patterns, further constrain the thermal and structural associations for hydrothermal alteration in the SRP-Y. Models for low-δ18O magmatism must be compatible with (1) δ18O(magma) trends within individual SRP-Y eruptive centers, (2) along axis trends in δ18O(magma), and (3) the high concentration of low-δ18O magmas relative to the surrounding regions. When considered with the structural and thermal evolution of the SRP-Y, these constraints support low-δ18O magma genesis originating from syn-hotspot meteoric hydrothermal alteration, driven by hotspot-derived thermal fluxes superimposed on extensional tectonics. This model is not restricted to continental hotspot settings and may apply to several other low-δ18O igneous provinces with similar thermal and structural associations.

  11. DECOVALEX-THMC Project. Task D. Long-Term Permeability/Porosity Changes in the EDZ and Near Field due to THM and THC Processes in Volcanic and Crystalline-Bentonite Systems. Phase 1 Report

    Energy Technology Data Exchange (ETDEWEB)

    Birkholzer, J.; Rutqvist, J.; Sonnenthal, E. [Lawrence Berkeley National Laboratory, CA (United States); Barr, D. [Office of Repository Development, DOE (United States)

    2007-02-15

    The general goal of this project is to encourage multidisciplinary interactive and cooperative research on modeling coupled processes in geologic formations in support of the performance assessment for underground storage of radioactive waste. Three multi-year project stages of DECOVALEX have been completed in the past decade, mainly focusing on coupled thermal-hydrological-mechanical processes. Currently, a fourth three-year project stage of DECOVALEX is under way, referred to as DECOVALEX-THMC. THMC stands for Thermal, Hydrological, Mechanical, and Chemical processes. The new project stage aims at expanding the traditional geomechanical scope of the previous DECOVALEX project stages by incorporating geochemical processes important for repository performance. The U.S. Department of Energy (DOE) leads Task D of the new DECOVALEX phase, entitled 'Long-term Permeability/Porosity Changes in the EDZ and Near Field due to THC and THM Processes for Volcanic and Crystalline-Bentonite Systems.' In its leadership role for Task D, DOE coordinates and sets the direction for the cooperative research activities of the international research teams engaged in Task D. The research program developed for Task D of DECOVALEX-THMC involves geomechanical and geochemical research areas. THM and THC processes may lead to changes in hydrological properties that are important for performance because the flow processes in the vicinity of emplacement tunnels will be altered from their initial state. Some of these changes can be permanent (irreversible), in which case they persist after the thermal conditions have returned to ambient; i.e., they will affect the entire regulatory compliance period. Geochemical processes also affect the water and gas chemistry close to the waste packages, which are relevant for waste package corrosion, buffer stability, and radionuclide transport. Research teams participating in Task D evaluate long-term THM and THC processes in two generic geologic

  12. Volcanology: Volcanic bipolar disorder explained

    Science.gov (United States)

    Jellinek, Mark

    2014-02-01

    Eruptions come in a range of magnitudes. Numerical simulations and laboratory experiments show that rare, giant super-eruptions and smaller, more frequent events reflect a transition in the essential driving forces for volcanism.

  13. Hygroscopic properties of volcanic ash

    National Research Council Canada - National Science Library

    T. L. Lathem; P. Kumar; A. Nenes; J. Dufek; I. N. Sokolik; M. Trail; A. Russell

    2011-01-01

      Volcanic ash is hygroscopic Water vapor adsorption is the main proceess controlling ash hygroscopicity The results can be parameterized in a simple correlation for use in models Limited observational...

  14. The volcanic and geochemical development of São Nicolau, Cape Verde Islands

    DEFF Research Database (Denmark)

    Duprat, Helene Inga; Holm, Paul Martin; Sherson, Jacob Friis

    2007-01-01

    We present 34 new age results from 40 Ar/39 Ar incremental heating analyses of groundmass separates from volcanic rocks from São Nicolau, Cape Verde. Combining the age results with field observations, we show that the volcanic activity that formed the island occurred in four separate stages: 1: >...

  15. Volcanic hazards and aviation safety

    Science.gov (United States)

    Casadevall, Thomas J.; Thompson, Theodore B.; Ewert, John W.; ,

    1996-01-01

    An aeronautical chart was developed to determine the relative proximity of volcanoes or ash clouds to the airports and flight corridors that may be affected by volcanic debris. The map aims to inform and increase awareness about the close spatial relationship between volcanoes and aviation operations. It shows the locations of the active volcanoes together with selected aeronautical navigation aids and great-circle routes. The map mitigates the threat that volcanic hazards pose to aircraft and improves aviation safety.

  16. Los volcanes y los hombres

    OpenAIRE

    García, Carmen

    2007-01-01

    Desde las entrañas de la tierra, los volcanes han creado la atmósfera, el agua de los océanos, y esculpido los relieves del planeta: son, pues, los zahoríes de la vida. Existen volcanes que los hombres explotan o cultivan, y otros sobre los cuales se han construido observatorios en los que se llevan a cabo avanzadas investigaciones científicas.

  17. Volcanic systems of Iceland and their magma source

    Science.gov (United States)

    Sigmarsson, Olgeir

    2017-04-01

    Several active hot-spot volcanoes produce magma from mantle sources which composition varies on decadal time scale. This is probably best demonstrated by the recent work of Pietruszka and collaborators on Kilauea, Hawaii. In marked contrast, basalt lavas from volcanic system in Iceland located above the presumed centre of the Iceland mantle plume have uniform isotope composition over the last 10 thousand years. Volcanic systems are composed of a central volcano and a fissure swarm, or a combination of both and they represent a fundamental component of the neovolcanic zones in Iceland. Four such systems, those of Askja, Bárðarbunga, Kverkfjöll and Grímsvötn in central Iceland were chosen for investigation. The last three have central volcanoes covered by the Vatnajökull ice-sheet whereas part of their fissure swarms is ice-free. Tephra produced during subglacial eruptions together with lavas from the fissure swarms of Holocene age have been collected and analysed for Sr, Nd and Th isotope ratios. Those volcanic formations that can be univocally correlated to a given volcanic system display uniform isotope ratio but different from one volcanic system to another. An exception to this regularity is that Askja products have isotope ratios indistinguishable from those of Gímsvötn, but since these volcanic systems lies far apart their lava fields do not overlap. A practical aspect of these findings was demonstrated during the rifting event of Bárðarbunga and fissure eruption forming the Holuhraun lava field. Relatively low, O isotope ratios in these basalts and heterogeneous macrocrystal composition have been ascribed to important metabasaltic crustal contamination with or without crystal mush recycling. In that case a surprisingly efficient magma mixing and melt homogenization must have occurred in the past beneath the volcanic systems. One possibility is that during the rapid deglaciation much mantle melting occurred and melts accumulated at the mantle

  18. Status of volcanism studies for the Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Crowe, B.; Perry, F.; Murrell, M.; Poths, J.; Valentine, G.A. [Los Alamos National Lab., NM (United States); Wells, S. [Univ. of California, Riverside, CA (United States); Bowker, L.; Finnegan, K. [Univ. of Nevada, Las Vegas, NV (United States); Geissman, J.; McFadden, L.

    1995-02-01

    Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The risk of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The Lathrop Wells volcanic center is described in detail because it is the youngest basalt center in the YMR. Chapter 3 describes the tectonic setting of the YMR and presents and assesses the significance of multiple alternative tectonic models. Geophysical data are described for the YMR and are used as an aid to understand the distribution of basaltic volcanic centers. Chapter 4 discusses the petrologic and geochemical features of basaltic volcanism in the YMR, the southern Great Basin and the Basin and Range province. The long time of activity and characteristic small volume of the Postcaldera basalt of the YMR result in one of the lowest eruptive rates in a volcanic field in the southwest United States. Chapter 5 summarizes current concepts of the segregation, ascent, and eruption of basalt magma. Chapter 6 summarizes the history of volcanism studies (1979 through early 1994), including work for the Yucca Mountain Site Characterization Project and overview studies by the state of Nevada and the Nuclear Regulatory Commission. Chapter 7 summarizes probabilistic volcanic hazard assessment using a three-part conditional probability model. Chapter 8 describes remaining volcanism work judged to be needed to complete characterization studies for the YMR. Chapter 9 summarizes the conclusions of this volcanism status report.

  19. March 2017 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2017-03-01

    Full Text Available No abstract available. Article truncated after 150 words. The March 2017 Arizona Thoracic Society meeting was held on Wednesday, March 22, 2017 at the HonorHealth Rehabilitation Hospital beginning at 6:30 PM. This was a dinner meeting with case presentations. There 11 attendance representing the pulmonary, critical care, sleep, thoracic surgery and radiology communities. There was a discussion of supporting the Tobacco 21 bill which had been introduced into the Arizona State Legislature. The bill was assigned to the House Commerce Committee but was not scheduled for a hearing by the Chair-Representative, Jeff Wininger from Chandler. It seems likely that the bill will be reintroduced in the future and the Arizona Thoracic Society will support the bill in the future. Three cases were presented: 1. Dr. Bridgett Ronan presented a 57-year-old man with cough and shortness of breath. His physical examination and spirometry were unremarkable. A thoracic CT scan showed large calcified and noncalcified pleural plaques and mediastinal lymphadenopathy. …

  20. December 2013 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Richard A. Robbins

    2013-12-01

    Full Text Available No abstract available. Article truncated at 150 words. A breakfast meeting of the Arizona Thoracic Society and the Tucson winter lung series was held on Saturday, 12/14/2013 at Kiewit Auditorium on the University of Arizona Medical Center Campus beginning at 8:30 AM. There were 31 in attendance. A lecture was presented by Joe G. N. "Skip" Garcia, MD, the senior vice president for health sciences at the University of Arizona. The title of Garcia’s talk was “Personalizing Medicine in Cardiopulmonary Disorders: The Post ACA Landscape”. Garcia began with reiterating that the Affordable Care Act (ACA, Obamacare is fact and could pose a threat to academic medical centers. However, he views the ACA as an opportunity to develop personalized medicine which grew from the human genome project. Examples cited included the genetic variability among patients in determining the dose of warfarin and bronchodilator response to beta agonists in asthma (1,2. Garcia’s laboratory has studied predominately 6 diseases including the …

  1. July 2013 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2013-07-01

    Full Text Available No abstract available. Article truncated after 150 words. The first Arizona Thoracic Society meeting in Tucson was held on Wednesday, 7/24/2013 at Kiewit Auditorium on the University of Arizona Medical Center campus beginning at 6:30 PM. There were 36 in attendance representing the pulmonary, critical care, sleep, pathology and radiology communities. Dinner was sponsored by Accredo Health Group. A brief discussion was held of plans to have the December 2013 meeting in Tucson on a weekend as part of the University of Arizona winter pulmonary meeting. There were 4 cases presented: 1.Mohammad Dalabih presented a case of a 48 yo woman with respiratory failure cared for by Gordon Carr, Linda Snyder, and himself. Radiology findings were discussed by Isabel Oliva. Lung biopsy showed acute fibrinous and organizing pneumonia rather than ARDS and was presented by Richard Sobonya. 2.Franz Rischard presented a case of a 61 year old with progressive dyspnea and moderate COPD with evidence of

  2. April 2014 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-04-01

    Full Text Available No abstract available. Article truncated at 150 words. The April 2014 Arizona Thoracic Society meeting was held on Wednesday, 4/23/2014 at Scottsdale Shea Hospital beginning at 6:30 PM. There were 15 in attendance representing the pulmonary, critical care, sleep, pathology and radiology communities. It was announced that there will be a wine tasting with the California, New Mexico and Colorado Thoracic Societies at the American Thoracic Society International Meeting. The tasting will be led by Peter Wagner and is scheduled for the Cobalt Room in the Hilton San Diego Bayfront on Tuesday, May 20, from 4-8 PM. Guideline development was again discussed. The consensus was to await publication of the IDSA Cocci Guidelines and respond appropriately. George Parides, Arizona Chapter Representative, gave a presentation on Hill Day. Representatives of the Arizona, New Mexico and Washington Thoracic Societies met with their Congressional delegations, including Rep. David Schweikert, to discuss the Cigar Bill, NIH funding, and the Medicare Sustainable Growth ...

  3. September 2017 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2017-09-01

    Full Text Available No abstract available. Article truncated at 150 words. The September 2017 Arizona Thoracic Society meeting was held on Wednesday, September 27, 2017 at the HonorHealth Rehabilitation Hospital beginning at 6:30 PM. This was a dinner meeting with case presentations. There were 16 in attendance representing the pulmonary, critical care, sleep, and radiology communities. There was a discussion of the Tobacco 21 bill which had been introduced the last session in the Arizona State Legislature. Since it seems likely that the bill will be reintroduced, the Arizona Thoracic Society will support the bill in the future. Dr. Rick Robbins announced that the SWJPCC has applied to be included in PubMed. In addition, Dr. Robbins was assigned the task of tracking down the campaign contributions to congressional members from the tobacco PAC before the next election. There were 7 case presentations: 1.\tAshley L. Garrett, MD, pulmonary fellow at Mayo, presented an elderly man with insulin-dependent diabetes who felt he …

  4. University of Arizona Compressed Air Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Joseph [Univ. of Arizona, Tucson, AZ (United States); Muralidharan, Krishna [Univ. of Arizona, Tucson, AZ (United States)

    2012-12-31

    Boiled down to its essentials, the grant’s purpose was to develop and demonstrate the viability of compressed air energy storage (CAES) for use in renewable energy development. While everyone agrees that energy storage is the key component to enable widespread adoption of renewable energy sources, the development of a viable scalable technology has been missing. The Department of Energy has focused on expanded battery research and improved forecasting, and the utilities have deployed renewable energy resources only to the extent of satisfying Renewable Portfolio Standards. The lack of dispatchability of solar and wind-based electricity generation has drastically increased the cost of operation with these components. It is now clear that energy storage coupled with accurate solar and wind forecasting make up the only combination that can succeed in dispatchable renewable energy resources. Conventional batteries scale linearly in size, so the price becomes a barrier for large systems. Flow batteries scale sub-linearly and promise to be useful if their performance can be shown to provide sufficient support for solar and wind-base electricity generation resources. Compressed air energy storage provides the most desirable answer in terms of scalability and performance in all areas except efficiency. With the support of the DOE, Tucson Electric Power and Science Foundation Arizona, the Arizona Research Institute for Solar Energy (AzRISE) at the University of Arizona has had the opportunity to investigate CAES as a potential energy storage resource.

  5. A Study of Arizona's Teachers of English Language Learners

    OpenAIRE

    Rios-Aguilar, Cecilia; González-Canche, Manuel; Moll, Luis

    2010-01-01

    Part 1 of the Arizona Educational Equity Project. Overall findings show that most of these Arizona teachers have a great deal of faith in their ELL students' ability to achieve at grade level but that the 4 hour ELD block to which they are assigned is not helping them to catch up with their English speaking peers. Related Documents A Study of Arizona's Teachers of English Language Learners Abstract: In this study a representative sample of 880 elementar...

  6. Life history attributes data for Arizona Grasshopper Sparrow (Ammodramus savannarum ammolegus) in Arizona 2013

    Science.gov (United States)

    Ruth, Janet M.

    2017-01-01

    Ammodramus savannarum ammolegus (commonly referred to as the Arizona Grasshopper Sparrow) occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this data was produced as part of the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. This study is described in the publication listed in the larger work citation of this metadata record. 

  7. Page 1 THE PANJAL TRAPS: ACID AND BASIC VOLCANIC ...

    Indian Academy of Sciences (India)

    1943-09-17

    THE PANJAL TRAPS: ACID AND BASIC. VOLCANIC ROCKS. BY P. N. GANJU, M.Sc. (Lecturer in Geology, University of Lucknow). Received September 17, 1943. (Communicated by Prof. L. Rama Rao, F.A.sc.) HB material on which this paper is based was collected by the author, mainly during the field work done in the ...

  8. Evidences for a volcanic province in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; Sudhakar, M.

    and in deciphering the source of the rock types. Further, the large manganese nodule fields in the CIB are seen to occur in conjunction with the volcanic materials, since the latter forms nuclei and substrates for ferromanganese deposits. It is concluded that a...

  9. Exploring Volcanism with Digital Technology in Undergraduate Education

    Science.gov (United States)

    McCoy, F. W.; Parisky, A.

    2016-12-01

    Volcanism as one of the most dynamic geological processes on this planet is also one of the most dramatic for attracting students to the earth sciences. At the University of Hawaii (UH) volcanism is used to attract students into the geosciences, coupled with its significant association to Hawaiian culture and contemporary issues such as those associated with related hazards - example: during the past century five towns were buried by lava flows on the Big Island, another recently threatened with destruction. To bring this dynamism into undergraduate education, UH focuses on field trips and courses to all islands; at Windward Community College (WCC/UH) a focus is provided through a series of field courses (1 credit) to all islands, especially the Big Island. Critical to the WCC effort are computer-generated animations and descriptions of volcanological processes for illustrating concepts undergraduate students find difficult: tumescence as an indicator of an eruption, fractional crystallization, collapse of volcanic edifices, explosive eruptions, weathering processes, hazards and mitigation, all embedded in the evolutionary story of mid-ocean volcanic islands such as those in Hawaii. Field courses require intense field labs, which are significantly assisted by digital platforms that include computer-generated illustrations, descriptions, animations, and more. The consequence for developing geoscientists has been outstanding.

  10. Revised paleomagnetic pole for the Sonoma Volcanics, California

    Science.gov (United States)

    Mankinen, E.A.

    1989-01-01

    Paleomagnetic sampling of the Miocene and Pliocene Sonoma Volcanics, northern California, was undertaken to supplement an earlier collection. Data from 25 cooling units yield positive fold and reversal tests, and a paleomagnetic pole located at 80.2??N., 069.2??E., with ??95 = 6.8??. This paleopole is significantly displaced (9.6?? ?? 5.3?? of latitude) to the farside of the geographic pole. A highly elliptical distribution of the data in both direction and VGP space indicates that incomplete averaging of geomagnetic secular variation is a more likely explanation for this anomaly than is northward translation of the volcanic field. -Author

  11. Venus - False Color of Volcanic Plains

    Science.gov (United States)

    1992-01-01

    This Magellan full-resolution mosaic of Venus, centered at 10 degrees north latitude, 301 degrees east longitude, shows an area replete with diverse volcanic features. The image, of an area 489 kilometers long by 311 kilometers wide (303 by 193 miles), is dominated by volcanic plains which appear mottled because of varying roughnesses of each solidified lava flow. The rougher the terrain the brighter it appears in the radar image. The small, bright bumps clustered in the left portion of the image are a grouping of small volcanoes called a shield field. Each shield volcano is approximately 2 to 5 kilometers (1.2 to 3.1 miles) in diameter and has very subdued relief. It is believed that the lava flows that make up each shield originates from a common source. To the right of the shield field is another type of volcano, called a scalloped dome. It is 25 kilometers (16 miles) in diameter and has a central pit. Some of the indistinct lobe-shaped pattern around the dome may either be lava flows or rocky debris which has fallen from the scalloped cliffs surrounding the domes. The small radial ridges characteristic of scalloped domes are remnants of catastrophic landslides. To the right of that feature is a large depression called a volcanic caldera. The caldera was formed when lava was expelled from an underground chamber, which when emptied, subsequently collapsed forming the depression. The feature furthermost to the east (right) is another scalloped dome, 35 kilometers (22 miles) in diameter. That feature is unusual in that lava came out through the southeastern margin, rafting a large portion of the dome for 20 kilometers (12 miles). The lava continues into the lower right portion of the area in the image. Its steep rounded boundaries suggest it was a very sticky, oozing lava. That same type of lava is what scientists propose formed the steep-sided domes such as the bright, round feature, slightly northeast of center. It is highly likely that the features are all part

  12. Whose reality counts? Factors affecting the perception of volcanic risk

    Science.gov (United States)

    Haynes, Katharine; Barclay, Jenni; Pidgeon, Nick

    2008-05-01

    Understanding how people perceive risk has become increasingly important for improving risk communication and reducing risk associated conflicts. This paper builds upon findings, methodologies and lessons learned from other fields to help understand differences between scientists, authorities and the public. Qualitative and quantitative methods were used to analyse underlying attitudes and judgements during an ongoing volcanic crisis on the Caribbean Island of Montserrat. Specific differences between the public, authorities and scientists were found to have been responsible for misunderstandings and misinterpretations of information and roles, resulting in differing perceptions of acceptable risk. Difficulties in the articulation and understanding of uncertainties pertaining to the volcanic risk led to a situation in which the roles of hazard monitoring, risk communication and public protection became confused. In addition, social, economic and political forces were found to have distorted risk messages, leading to a public reliance upon informal information networks. The implications of these findings for volcanic risk management and communication are discussed.

  13. 77 FR 25737 - Notice of Intent To Repatriate Cultural Items: Arizona State Museum, University of Arizona...

    Science.gov (United States)

    2012-05-01

    ... present in the collections. In December 1950, the Gila Pueblo Foundation closed and the collections were... material culture are consistent with the Hohokam archeological tradition and indicate occupation between... Pueblo Foundation closed and the collections were donated to the Arizona State Museum. The one...

  14. How Arizona's Dropout Crisis Affects Communities, Creates Economic Losses for the State of Arizona

    Science.gov (United States)

    WestEd, 2014

    2014-01-01

    One-in-five of Arizona's youth did not complete high school and a similarly large proportion of the state's youth is disconnected from either work or education. These youth face higher risks of unemployment and economic insecurity and are more reliant on government supports. This situation, which fails to ensure that the state's youth are…

  15. On the visibility of airborne volcanic ash and mineral dust

    Science.gov (United States)

    Weinzierl, B.; Sauer, D. N.; Minikin, A.; Reitebuch, O.; Dahlkötter, F.; Mayer, B. C.; Emde, C.; Tegen, I.; Gasteiger, J.; Petzold, A.; Veira, A.; Kueppers, U.; Schumann, U.

    2012-12-01

    aerosol layer and the background, the illumination, the particle size distribution and mass concentration, the wavelength-dependent light scattering and absorption by the aerosol layer, the human perception, etc. In addition, the optical depth along the line of sight through an aerosol layer is more important than just the (vertical) optical depth, which is measured, for example, by sun photometers or satellites. The results of our study are in particular interesting for the question on the visibility of volcanic ash. Our analyses of "visible ash" demonstrate that under clear sky conditions volcanic ash is visible already at concentrations far below what is currently considered as the upper limit for safe operation of an aircraft engine (2 mg m-3). The presence of a grayish-brown layer in the atmosphere does not unambiguously indicate the presence of volcanic ash. An uninformed observer is unlikely to identify an aged volcanic ash layer in his field of view without further information. The presence of clouds would make it even more complicated to visually detect volcanic ash. In regions with high background aerosol loading in the atmosphere from natural or anthropogenic influences, such as seen in large parts of Asia, the visual detection of volcanic ash as an additional contaminant will be substantially more difficult.

  16. Sismos y volcanes en Colombia

    OpenAIRE

    Duque Escobar, Gonzalo

    2010-01-01

    Notas sobre las zonas de amenaza sísmica y principales fuentes sísmicas de Colombia, y los segmentos volcánicos de los Andes colombianos con los principales volcanes activos, de conformidad con los estudios del Ingeominas. Anexos a títulos con sus correspondientes enlaces, para ofrecer artículos relacionados con sismos y volcanes, en los que se consideran aspectos de interés para la gestión del riesgo sísmico y volcánico en Colombia

  17. Structural significance of the south Tyrrhenian volcanism

    Science.gov (United States)

    Gaudiosi, G.; Musacchio, G.; Ventura, G.; de Astis, G.

    2003-04-01

    The southern part of the Tyrrhenian Sea represents a transition from ocenic- (the Tyrrhenian Sea) to continental-domain (the Calabrian Arc) and is affected by active calkalkaline to potassic volcanism (the Eolian Islands). Active extensional tectonics, coupled with the general upwelling of northern Sicily and Calabria continental crust, coexists with active subduction of the Ionian Plate beneath the Calabrian Arc. This has been interpreted as the result of the detachment of the slab beneath the Calbrian Arc. Present-day tectonics is characterized by NE-SW normal faults and NNW- SSE dextral oblique-slip faults. The normal faults form the major peri- Tyrrhenian basins. Refraction and high resolution onshore-offshore wide-angle-reflection profiles, as well as potential field modeling, provide a 3D image of the Moho. Short wave-length undulations characterize the Moho beneath the Aeolian Arch. The major upraise is about 6 km, beneath the Aeolian active volcanic area, and affects all the crustal boundaries. Another sharp crustal thinning is observed beneath the gulf of Patti at the south-eastern edge of the Tyrrhenian basin. We suggest that the graben-like structure, occurring along the Salina-Lipari-Vulcano islands and oriented at high angles to the trench, is lithospheric and can be followed down to Moho depths. NNW-SSE dextral oblique-slip faults, like the Tindari Letojanni fault system, control the Salina-Lipari-Vulcano portion of the Aeolian volcanism and connect the oceanic crust of the Marsili Basin to the Malta Escarpment, through the Etna volcano. Across this lineament seismicity changes from mostly shallow to the west, to deep intra- slab to the east.

  18. Arizona Lesson Observation and Evaluation (ALOE): Design Test Edition, 1990.

    Science.gov (United States)

    Fargo, J. Steven; And Others

    The Arizona Lesson Observation and Evaluation (ALOE) system of evaluating teaching is presented. ALOE was developed from Arizona adaptations of the Georgia Teacher Performance Assessment Instruments and, with G. Taylor's "Functional Elements Analysis of Teaching Skills" (FEATS), forms an integrated observation package which allows…

  19. Transformational Leadership and Teacher Motivation in Southwestern Arizona High Schools

    Science.gov (United States)

    Reynolds, Catherine L.

    2009-01-01

    The purpose of this study was to explore the relationship between transformational leadership and teacher motivation in Southwestern Arizona high schools. Teachers in a school district in Southwestern Arizona comprised of high schools were surveyed using two instruments, Leithwood and Jantzi's (1998) The Leadership and Management of Schools in…

  20. Applying Water-Level Difference Control to Central Arizona Project

    Science.gov (United States)

    The Central Arizona Project (CAP) has been supplying Colorado River water to Central Arizona for roughly 25 years. The CAP canal is operated remotely with a Supervisory Control and Data Acquisition (SCADA) System. Gate position changes are made either manually or through the use of automatic control...

  1. 7 CFR 1131.2 - Arizona marketing area.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Arizona marketing area. 1131.2 Section 1131.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE ARIZONA MARKETING AREA Order Regulating...

  2. Innovations in Arizona's Accountability Policies and Frameworks for Alternative Schools

    Science.gov (United States)

    Schlessman, Amy

    2014-01-01

    This study presents Arizona's innovations in academic accountability policy and academic accountability frameworks for alternative schools. A timeline of statutes and regulations including the State Board of Education approved alternative school definition provides Arizona's context for alternative school accountability policy and frameworks.…

  3. Arizona Commission of Indian Affairs 1983 Annual Report.

    Science.gov (United States)

    Arizona Commission of Indian Affairs, Phoenix.

    Intended to provide insight into the proceedings, transactions, and findings of the Arizona Commission of Indian Affairs, the 1983 annual report reflects the Commission's continued efforts to improve communications and understanding, and especially to strengthen working relationships between Arizona tribes and state government. The report…

  4. Arizona Commission of Indian Affairs 1974-75 Annual Report.

    Science.gov (United States)

    Arizona Commission of Indian Affairs, Phoenix.

    The Arizona Commission of Indian Affairs 1974-75 Annual Report is issued to inform the Governor, State Legislature, and tribal governments of the proceedings, transactions, findings, and recommendations made by the commission. Included are: (1) a list of commission members, (2) a map showing the Indian reservations in Arizona, (3) a table listing…

  5. The impact of Arizona Highways Magazine on tourism.

    Science.gov (United States)

    2012-03-01

    The purpose of this study was to: 1) examine the effect of Arizona Highways Magazine (AHM) on tourism, 2) determine trip : characteristics of AHM subscribers traveling in Arizona, and 3) calculate a benefit/cost ratio for AHM based on the : magazine...

  6. UNIVERSITY OF ARIZONA HIGH ENERGY PHYSICS PROGRAM

    Energy Technology Data Exchange (ETDEWEB)

    Rutherfoord, John P. [University of Arizona; Johns, Kenneth A. [University of Arizona; Shupe, Michael A. [University of Arizona; Cheu, Elliott C. [University of Arizona; Varnes, Erich W. [University of Arizona; Dienes, Keith [University of Arizona; Su, Shufang [University of Arizona; Toussaint, William Doug [University of Arizona; Sarcevic, Ina [University of Arizona

    2013-07-29

    The High Energy Physics Group at the University of Arizona has conducted forefront research in elementary particle physics. Our theorists have developed new ideas in lattice QCD, SUSY phenomenology, string theory phenomenology, extra spatial dimensions, dark matter, and neutrino astrophysics. The experimentalists produced significant physics results on the ATLAS experiment at CERN's Large Hadron Collider and on the D0 experiment at the Fermilab Tevatron. In addition, the experimentalists were leaders in detector development and construction, and on service roles in these experiments.

  7. 76 FR 14048 - Notice of Intent To Repatriate a Cultural Item: Arizona State Museum, University of Arizona...

    Science.gov (United States)

    2011-03-15

    ..., ] Tucson, AZ, that meets the definition of sacred object and object of cultural patrimony under 25 U.S.C... the sacred object/object of cultural patrimony and the Navajo Nation of Arizona, New Mexico and Utah.../object of cultural patrimony should contact John McClelland, NAGPRA Coordinator, Arizona State Museum...

  8. Hubble Captures Volcanic Eruption Plume From Io

    Science.gov (United States)

    1997-01-01

    The Hubble Space Telescope has snapped a picture of a 400-km-high (250-mile-high) plume of gas and dust from a volcanic eruption on Io, Jupiter's large innermost moon.Io was passing in front of Jupiter when this image was taken by the Wide Field and Planetary Camera 2 in July 1996. The plume appears as an orange patch just off the edge of Io in the eight o'clock position, against the blue background of Jupiter's clouds. Io's volcanic eruptions blasts material hundreds of kilometers into space in giant plumes of gas and dust. In this image, material must have been blown out of the volcano at more than 2,000 mph to form a plume of this size, which is the largest yet seen on Io.Until now, these plumes have only been seen by spacecraft near Jupiter, and their detection from the Earth-orbiting Hubble Space Telescope opens up new opportunities for long-term studies of these remarkable phenomena.The plume seen here is from Pele, one of Io's most powerful volcanos. Pele's eruptions have been seen before. In March 1979, the Voyager 1 spacecraft recorded a 300-km-high eruption cloud from Pele. But the volcano was inactive when the Voyager 2 spacecraft flew by Jupiter in July 1979. This Hubble observation is the first glimpse of a Pele eruption plume since the Voyager expeditions.Io's volcanic plumes are much taller than those produced by terrestrial volcanos because of a combination of factors. The moon's thin atmosphere offers no resistance to the expanding volcanic gases; its weak gravity (one-sixth that of Earth) allows material to climb higher before falling; and its biggest volcanos are more powerful than most of Earth's volcanos.This image is a contrast-enhanced composite of an ultraviolet image (2600 Angstrom wavelength), shown in blue, and a violet image (4100 Angstrom wavelength), shown in orange. The orange color probably occurs because of the absorption and/or scattering of ultraviolet light in the plume. This light from Jupiter passes through the plume and is

  9. Automatic classification of seismo-volcanic signatures

    Science.gov (United States)

    Malfante, Marielle; Dalla Mura, Mauro; Mars, Jérôme; Macedo, Orlando; Inza, Adolfo; Métaxian, Jean-Philippe

    2017-04-01

    The prediction of volcanic eruptions and the evaluation of their associated risks is still a timely and open issue. For this purpose, several types of signals are recorded in the proximity of volcanoes and then analysed by experts. Typically, seismic signals that are considered as precursor or indicator of an active volcanic phase are detected and manually classified. In this work, we propose an architecture for automatic classification of seismo-volcanic waves. The system we propose is based on supervised machine learning. Specifically, a prediction model is built from a large dataset of labelled examples by the means of a learning algorithm (Support Vector Machine or Random Forest). Four main steps are involved: (i) preprocess the signals, (ii) from each signal, extract features that are useful for the classes discrimination, (iii) use an automatic learning algorithm to train a prediction model and (iv) classify (i.e., assign a semantic label) newly recorded and unlabelled examples. Our main contribution lies in the definition of the feature space used to represent the signals (i.e., in the choice of the features to extract from the data). Feature vectors describe the data in a space of lower dimension with respect to the original one. Ideally, signals are separable in the feature space depending on their classes. For this work, we consider a large set of features (79) gathered from an extensive state of the art in both acoustic and seismic fields. An analysis of this feature set shows that for the application of interest, 11 features are sufficient to discriminate the data. The architecture is tested on 4725 seismic events recorded between June 2006 and September 2011 at Ubinas, the most active volcano of Peru. Six main classes of signals are considered: volcanic tremors (TR), long period (LP), volcano-tectonic (VT), explosion (EXP), hybrids (HIB) and tornillo (TOR). Our model reaches above 90% of accuracy, thereby validating the proposed architecture and the

  10. A Reconstruction of Paleo-Positions of Basin and Range Volcanic Rocks, and Implications for Tectonic Controls on Volcanism

    Science.gov (United States)

    Platt, B. W.; Putirka, K. D.

    2011-12-01

    A key problem in understanding the tectonic triggers of Basin-and-Range magmatism relates to the fact that many volcanic rocks have been translated from the latitudes and longitudes at which they were erupted. We present a reconstruction of the paleo-latitudes and paleo-longitudes of volcanic rocks using the work of Snow and Wernicke (2000). These reconstructed volcanic rock positions are used to 1) test whether the formation and northward migration of the Mendocino Triple Junction (MTJ) may have initiated volcanism and 2) whether the demise of subduction processes may have affected volcanic compositions. We utilize Figure 13 from Snow and Wernicke (2000) in the reconstruction, which illustrates a deformation grid that covers the most extended parts of the Basin and Range in CA, NV and AZ. We apply deformation a vector to each grid point and assigned an age of initiation of deformation, which we allow to migrate from south to north based on field evidence for the initiation of extensional faulting in the map area (Anderson et al., 1988; Beratan and Nielsen, 1996; Fridrich et al., 1998; Faulds et al., 2002; Jacobsen et al., 2002; Busby and Putirka, 2009). Our model, derived from the field data, yields an initiation age (for extension) as a function of latitude: Age of initiation of deformation [Ma]=130.6 - 3.14[Latitude]. This reconstruction provides a consistency test for the extension model of Snow and Wernicke (2000) because our reconstruction yields strain rates for each grid point; we obtain a mean strain rate of 13 mm/year, which is consistent with strain rates obtained from field data. Interestingly, the latitudinal changes for volcanic rocks are mostly minimal; even though in the Walker Lane belt crustal components have experienced significant latitudinal displacement, most volcanic rocks erupted in the Walker Lane are too young to be greatly translated. However, many volcanic rocks are sufficiently old so that longitudinal positions are significantly

  11. November 2014 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-11-01

    Full Text Available No abstract available. Article truncated after 150 words. The November 2014 Arizona Thoracic Society meeting was held on Wednesday, November 19, 2014 at the Scottsdale Shea Hospital beginning at 6:30 PM. This was a dinner meeting with case presentations. There were about 30 in attendance representing the pulmonary, critical care, sleep, pathology and radiology communities. Jud Tillinghast was nominated as the Arizona Thoracic Society physician of the year. Three cases were presented: 1. George Parides presented a case of a 70-year-old woman with a 3 areas of ground glass picked up incidentally on CT scan. She had some wheezing. A needle biopsy revealed adenocarcinoma. The biopsy and radiologic pattern were consistent with adenocarcinoma in situ or minimally invasive adenocarcinoma. Discussion centered around treatment. Most felt that if the areas could be removed that surgical resection was indicated (1. 2. Lewis Wesselius presented a 60-year-old man with Marfan's syndrome and a history of an aortic valve replacement on chronic ...

  12. June 2014 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-06-01

    Full Text Available No abstract available. Article truncated at 150 words. The June 2014 Arizona Thoracic Society meeting was held on Wednesday, 6/25/14 at the Bio5 building on the University of Arizona Medical Center campus in Tucson beginning at 5:30 PM. This was a dinner meeting with case presentations. There were about 33 in attendance representing the pulmonary, critical care, sleep, pathology and radiology communities. Four cases were presented: Eric Chase presented a 68 year old incarcerated man shortness of breath, chest pain and productive cough. The patient was a poor historian. He was supposed to be receiving morphine for back pain but this had been held. He also had a 45 pound weight loss over the past year. His PMH was positive for COPD, hypertension, congestive heart failure, chronic back pain and hepatitis C. Past surgical history included a back operation and some sort of chest operation. On physical examination he was tachypneic, tachycardic and multiple scars over his neck ...

  13. November 2017 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2017-11-01

    Full Text Available No abstract available. Article truncated after 150 words. The November 2017 Arizona Thoracic Society meeting was held on Wednesday, November 15, 2017 at the HonorHealth Rehabilitation Hospital beginning at 6:30 PM. This was a dinner meeting with a lecture followed by case presentations. There were 15 in attendance representing the pulmonary, critical care, sleep, allergy, infectious disease and radiology communities. At the beginning of the meeting several issues were discussed: 1. CME offered by the Southwest Journal of Pulmonary and Critical Care Medicine (SWJPCC is currently offered to only the Southwest state thoracic societies and the Mayo Clinic. After discussion it was felt that this restriction of access was no longer appropriate and CME credits should be available to all. 2. Efforts continue to obtain CME for the Arizona Thoracic Society meetings. Our Chapter Representative, Dr. Gerry Schwartzberg, is approaching this with the American Thoracic Society. Locally, HonorHealth sent out a survey on CME needs. Members were encouraged …

  14. 'Road rage' in Arizona: armed and dangerous.

    Science.gov (United States)

    Miller, Matthew; Azrael, Deborah; Hemenway, David; Solop, Frederic I

    2002-11-01

    Little is known about the relationship between firearm carrying and hostile behavior on the roadway. To explore a possible association between firearm carrying by drivers and hostile driving behavior we conducted a random-digit-dial survey of 790 licensed drivers in Arizona. In addition to demographic questions, we asked whether respondents had carried a gun while driving in the 12 months prior to the survey. Respondents were also asked if they, in anger, had personally made obscene gestures, cursed or shouted at other drivers, impeded another drivers progress with their vehicle, aggressively 'followed another driver too closely', or brandished a gun at another driver. We used multivariable logistic regression to explore correlates of hostile driving behavior while taking into account several demographic and behavioral characteristics. Overall 11% of drivers always (4%) or sometimes (7%) carried a gun with them in their vehicle; 34% report having made obscene gestures/cursed/shouted angrily; 28% report aggressively following or blocking other drivers with their vehicle. In both crude and multivariate adjusted analyses, self-report of engaging in hostile behavior while driving was significantly more common among men, young adults, and individuals who carried a firearm in their car. Our findings suggest that, at least among Arizona motorists, having a gun in the car is a strong marker for aggressive and illegal behavior behind the wheel.

  15. Garcia resigns as Arizona university VP

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2016-12-01

    Full Text Available No abstract available. Article truncated at 150 words. Dr. Joe G.N. "Skip" Garcia resigned his administrative duties as senior vice president for health sciences at the University of Arizona. Garcia said he would devote his full attention as a professor at the UA College of Medicine-Tucson according to the Arizona Republic (1. "After much thought and reflection, I have decided that the time is right for me to take a step back and focus on my continually growing research commitments," Garcia said. "Please know that this decision was an exceptionally difficult one and not reached lightly, and that I am humbled by all of your support during my time as senior vice president." Garcia was hired in 2013 to oversee the university's medical schools in Phoenix and Tucson, as well as the schools of nursing, pharmacy and public health. Shortly after Garcia was hired, he reorganized UA health sciences, recruited a roster of academics and tightened oversight of …

  16. May 2014 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-06-01

    Full Text Available No abstract available. Article truncated after first 150 words. The May 2014 Arizona Thoracic Society meeting was held on Wednesday, 5/28/2014 at Scottsdale Shea Hospital beginning at 6:30 PM. There were 13 in attendance representing the pulmonary, critical care, sleep and radiology communities. A discussion was held regarding the Arizona Thoracic Society relationship with the American Lung Association. Several members volunteered to talk to the lung association regarding common ground to strengthen the relationship. The wine tasting with the California, New Mexico and Colorado Thoracic Societies at the American Thoracic Society International Meeting was a big success. There were about 55 at the meeting. The tasting will probably be held again next year. At the ATS meeting data was presented that pirfenidone was effective in reducing the progression of idiopathic pulmonary fibrosis (IPF. The data was published in the New England Journal of Medicine on 8/29/14 (1. Lewis Wesselius is one of the investigators enrolling patients in a phase ...

  17. September 2013 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2013-09-01

    Full Text Available No abstract available. Article truncated at 150 words. The September Arizona Thoracic Society meeting was held on Wednesday, 9/25/2013 at Shea Hospital beginning at 6:30 PM. There were 13 in attendance representing the pulmonary, critical care, sleep, and pathology communities. After a brief discussion, Gerry Swartzberg was selected as Arizona’s 2014 nominee for Clinician of the Year. There was 1 case presented: Dr. Thomas Colby, pulmonary pathologist from Mayo Clinic Arizona, presented the case of a 67 year old woman with multiple pulmonary nodules. The largest was 1.2 cm CT scan. She had a fine needle aspiration of one of the nodules. The pathology revealed spindle-shaped cells which were synaptophysin + (also known as the major synaptic vesicle protein p38. Synaptophysin marks neuroendocrine tissue and on this basis the patient was diagnosed with multiple carcinoid tumors. Aguayo et al. (1 described six patients with diffuse hyperplasia and dysplasia of pulmonary neuroendocrine cells, multiple carcinoid tumorlets, and peribronchiolar fibrosis …

  18. August 2013 Arizona Thoracic Society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2013-08-01

    Full Text Available No abstract available. Article truncated after first 150 words. The August Arizona Thoracic Society meeting was held on Wednesday, 8/28/2013 at Shea Hospital beginning at 6:30 PM. There were 23 in attendance representing the pulmonary, critical care, sleep, and pathology communities. A brief discussion was held about the audio-visual aids available. It was generally agreed that our current projector is inadequate. Judd Tillinghast will inquire about using a hospital overhead projector. If that is not possible, it was agreed to purchase a new projector. Plans for telecasting the meeting between Phoenix and Tucson continue. A trial of a link between Shea and the University in Tucson failed. Once the link is successfully established, it is hoped that the meeting can be telecasted. There were 6 cases presented: 1. Dr. Thomas Colby, pulmonary pathologist from Mayo Clinic Arizona, presented the case of a 10 year old boy with chronic dyspnea for > 4 yrs. He had growth retardation since age …

  19. The scientific management of volcanic crises

    Science.gov (United States)

    Marzocchi, Warner; Newhall, Christopher; Woo, Gordon

    2012-12-01

    Sound scientific management of volcanic crises is the primary tool to reduce significantly volcanic risk in the short-term. At present, a wide variety of qualitative or semi-quantitative strategies is adopted, and there is not yet a commonly accepted quantitative and general strategy. Pre-eruptive processes are extremely complicated, with many degrees of freedom nonlinearly coupled, and poorly known, so scientists must quantify eruption forecasts through the use of probabilities. On the other hand, this also forces decision-makers to make decisions under uncertainty. We review the present state of the art in this field in order to identify the main gaps of the existing procedures. Then, we put forward a general quantitative procedure that may overcome the present barriers, providing guidelines on how probabilities may be used to take rational mitigation actions. These procedures constitute a crucial link between science and society; they can be used to establish objective and transparent decision-making protocols and also clarify the role and responsibility of each partner involved in managing a crisis.

  20. Payenia volcanic province, southern Mendoza, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina; Holm, Paul Martin; Llambias, Eduardo Jorge

    2013-01-01

    to the low thickness of the lithospheric mantle and preheating of the lower crust by earlier Mio-Pliocene volcanism. Rare earth element modelling of mantle melting calls for enriched source compositions and a beginning of melting within the garnet stability field for all Payenia basalts. The Río Colorado......The Pleistocene to Holocene Payenia volcanic province is a backarc region of 60,000 km2 in Mendoza, Argentina, which is dominated by transitional to alkaline basalts and trachybasalts. We present major and trace element compositions of 139 rocks from this area of which the majority are basaltic...... rocks with 4 to 12 wt.% MgO and 44 to 50 wt.% SiO2. The southern Payenia province is dominated by intraplate basalts and the trace element patterns of the Río Colorado and Payún Matrú lavas suggest little or no influence from subducted slab components. The mantle source of these rocks is similar to some...

  1. The mechanisms underpinning Cenozoic intraplate volcanism in eastern Australia: Insights from seismic tomography and geodynamic modeling

    Science.gov (United States)

    Rawlinson, N.; Davies, D. R.; Pilia, S.

    2017-10-01

    Cenozoic intraplate volcanism is widespread throughout much of eastern Australia and manifests as both age-progressive volcanic tracks and non-age-progressive lava fields. Various mechanisms have been invoked to explain the origin and distribution of the volcanism, but a broad consensus remains elusive. We use results from seismic tomography to demonstrate a clear link between lithospheric thickness and the occurrence, composition, and volume of volcanic outcrop. Furthermore, we find that non-age-progressive lava fields overlie significant cavities in the base of the lithosphere. Based on numerical simulations of mantle flow, we show that these cavities generate vigorous mantle upwellings, which likely promote decompression melting. However, due to the intermittent nature of the lava field volcanics over the last 50 Ma, it is probable that transient mechanisms also operate to induce or enhance melting. In the case of the Newer Volcanics Province, the passage of a nearby plume appears to be a likely candidate. Our results demonstrate why detailed 3-D variations in lithospheric thickness, plate motion, and transient sources of mantle heterogeneity need to be considered when studying the origin of non age-progressive volcanism in continental interiors.

  2. Calderas and mineralization: volcanic geology and mineralization in the Chianti caldera complex, Trans-Pecos Texas

    Energy Technology Data Exchange (ETDEWEB)

    Duex, T.W.; Henry, C.D.

    1981-01-01

    This report describes preliminary results of an ongoing study of the volcanic stratigraphy, caldera activity, and known and potential mineralization of the Chinati Mountains area of Trans-Pecos Texas. Many ore deposits are spatially associated with calderas and other volcanic centers. A genetic relationship between calderas and base and precious metal mineralization has been proposed by some and denied by others. Steven and others have demonstrated that calderas provide an important setting for mineralization in the San Juan volcanic field of Colorado. Mineralization is not found in all calderas but is apparently restricted to calderas that had complex, postsubsidence igneous activity. A comparison of volcanic setting, volcanic history, caldera evolution, and evidence of mineralization in Trans-Pecos to those of the San Juan volcanic field, a major mineral producer, indicates that Trans-Pecos Texas also could be an important mineralized region. The Chianti caldera complex in Trans-Pecos Texas contains at least two calderas that have had considerable postsubsidence activity and that display large areas of hydrothermal alteration and mineralization. Abundant prospects in Trans-Pecos and numerous producing mines immediately south of the Trans-Pecos volcanic field in Mexico are additional evidence that ore-grade deposits could occur in Texas.

  3. The Extremes of Volcanic Activity: Earth and Jupiter's Moon Io

    Science.gov (United States)

    Lowes, L. L.; Lopes, R.

    2004-12-01

    Jupiter's moon Io is the solar system's most volcanically active body, and the only place that magmatic volcanic eruptions have been observed beyond Earth. One of the first images of Io obtained by NASA's Voyager 1 spacecraft in 1979 shows a plume above one of its volcanoes. The NASA Voyager and Galileo spacecraft imaged many explosive eruptions of plumes and deposits - which travel hundreds of kilometers (farther than on the Earth or the Moon). Very hot lavas that are erupting from volcanic vents on Io may be similar to lavas that erupted on Earth billions of years ago. Understanding the physical processes driving volcanic eruptions is important for the understanding of terrestrial volcanoes, not only because of their potential hazards, but also as geologic resources, biologic environments, and for their role in shaping the surface of Earth and other planets. Volcanic eruptions are perhaps the most dramatic events on Earth, and are of intrinsic interest to students, youth, and adults. Topics involving volcanoes are a part of the national science education benchmarks for understanding the Earth's composition and structure for grades 6-8 (the process of creating landforms) and grades 9-12 (the effects of movement of crustal plates). Natural events on Earth coupled with exciting discoveries in space can serve to heighten the awareness of these phenomena and provide learning opportunities for real world applications of science. Educational applications for youth to compare volcanic activity on Io and Earth have been done through NASA-sponsored field trip workshops to places such as Yellowstone National Park (allowing educators to experience environments similar to those on other worlds), targeted classroom and hands-on activities, special interest books, and other resources. A sampling of such activities will be presented, and discussion invited on other related developmentally appropriate resources and activities.

  4. A Long Pleistocene Paleoclimate Record from Stoneman Lake, Arizona

    Science.gov (United States)

    Fawcett, P. J.; Anderson, R. S.; Brown, E. T.; Werne, J. P.; Jimenez-Moreno, G.; Toney, J. L.; Garcia, D.; Garrett, H. L.; Dunbar, N. W.

    2015-12-01

    Long continuous lake sediment cores provide enormous potential for interpreting climate change. In the American Southwest, long records are revolutionizing our understanding of megadroughts, which have occurred in the past and will most certainly occur in the future with rapidly changing climate. One site with the potential to study ancient megadroughts is Stoneman Lake, central Arizona, whose basin is a circular depression formed by a collapse in late Tertiary volcanics. The lake is spring fed, most recently alternating between a marsh and a lake, with water levels having fluctuated by > 3 meters over the last 25 years. Its small closed drainage basin (ca. 2.5 km2) with one small inflowing stream is key to the sensitivity of the record. Two parallel lacustrine sediment cores (70 m and 30 m deep) were recovered in October of 2014. Our preliminary chronology includes 8 AMS dates in the upper 7 m and two distinct tephras at 30.8 m depth and 36.3 m depth. Radiocarbon dates show a 2.7-m-thick Holocene section, and then a low Pleistocene SAR with an age of 11,000 cal yr B.P. at ~2.8 m to an age of 46,500 cal yr B.P. at 4.2 m depth. We estimate that the 70-m deep hole will provide a climate record back to ~1.3 million years ago. Of particular interest are the interglacials that serve as good analogs for future climate including MIS 11 and MIS 19. Initial core description includes MS, bulk density and high-resolution images. Holocene sediments are characterized by massive, dark organic rich silty clays with no distinct lamination. Sediments from the Last Glacial Maximum are well-laminated, light brown silty clays with few organics present. The distinctive laminations probably represent a very deep lake and therefore a wet cold climate, also verified by pollen data. There are several repeated intervals of laminated sediments deeper in the core that may represent older glacial maxima. Future work will include detailed pollen, plant macrofossil and charcoal analysis

  5. Solar energy system performance evaluation: Seasonal report for Elcam Tempe Arizona State University, Tempe, Arizona

    Science.gov (United States)

    1980-01-01

    The solar system, Elcam-Tempe, was designed by Elcam Incorporated, Santa Barbara, California, to supply commercial domestic hot water heating systems to the Agriculture Department residence at Arizona State University. The building is a single story residence located at the agriculture experiment farm of the Arizona State University. The energy system's four modes of operation are described. Electrical energy savings at the site was a net of 5.54 million Btu after the 0.17 million Btu of operating energy required to operate collector loop circulating pump were subtracted. The energy savings due to solar was less than the system's potential. On an average, twice as much hot water could have been used with significant solar energy contribution. The system corrosion and deposits caused by using dissimilar metals in the collector loop was the only problem noted with the Elcam-Tempe system.

  6. Potential volcanic impacts on future climate variability

    Science.gov (United States)

    Bethke, Ingo; Outten, Stephen; Otterå, Odd Helge; Hawkins, Ed; Wagner, Sebastian; Sigl, Michael; Thorne, Peter

    2017-11-01

    Volcanic activity plays a strong role in modulating climate variability. Most model projections of the twenty-first century, however, under-sample future volcanic effects by not representing the range of plausible eruption scenarios. Here, we explore how sixty possible volcanic futures, consistent with ice-core records, impact climate variability projections of the Norwegian Earth System Model (NorESM) under RCP4.5 (ref. ). The inclusion of volcanic forcing enhances climate variability on annual-to-decadal timescales. Although decades with negative global temperature trends become ~50% more commonplace with volcanic activity, these are unlikely to be able to mitigate long-term anthropogenic warming. Volcanic activity also impacts probabilistic projections of global radiation, sea level, ocean circulation, and sea-ice variability, the local-scale effects of which are detectable when quantifying the time of emergence. These results highlight the importance and feasibility of representing volcanic uncertainty in future climate assessments.

  7. Medical marijuana wins in California and Arizona.

    Science.gov (United States)

    James, J S

    1996-11-15

    Both California and Arizona have passed State legislation allowing medical use of marijuana, however, the law may now be unenforceable because of Federal laws against marijuana use for any reason. It is believed that some middle ground between allowing limited use of marijuana and outright banning is necessary considering today's medical needs. Among the demographic breakdowns on support of Proposition 215, allowing medicinal use of marijuana, was the observation that parents with children under 18 showed almost as much support for its passage as other adults, indicating no fear of it becoming abused by youth. Despite polls repeatedly showing support for the right to use marijuana for medical purposes, 44.3 percent still voted against it. The reasons are not known, but it is suggested that if the objections could be found and responded to, the initiative may work well enough to be an effective national model.

  8. Aquarious Mountain Area, Arizona: APossible HDR Prospect

    Energy Technology Data Exchange (ETDEWEB)

    West, F.G.; Laughlin, A.W.

    1979-05-01

    Exploration for Hot Dry Rock (HDR) requires the ability to delineate areas of thermal enhancement. It is likely that some of these areas will exhibit various sorts of anomalous conditions such as seismic transmission delays, low seismic velocities, high attenuation of seismic waves, high electrical conductivity in the crust, and a relatively shallow depth to Curie point of Magnetization. The Aquarius Mountain area of northwest Arizona exhibits all of these anomalies. The area is also a regional Bouguer gravity low, which may indicate the presence of high silica type rocks that often have high rates of radioactive heat generation. The one deficiency of the area as a HDR prospect is the lack of a thermal insulating blanket.

  9. Source mechanisms of volcanic tsunamis.

    Science.gov (United States)

    Paris, Raphaël

    2015-10-28

    Volcanic tsunamis are generated by a variety of mechanisms, including volcano-tectonic earthquakes, slope instabilities, pyroclastic flows, underwater explosions, shock waves and caldera collapse. In this review, we focus on the lessons that can be learnt from past events and address the influence of parameters such as volume flux of mass flows, explosion energy or duration of caldera collapse on tsunami generation. The diversity of waves in terms of amplitude, period, form, dispersion, etc. poses difficulties for integration and harmonization of sources to be used for numerical models and probabilistic tsunami hazard maps. In many cases, monitoring and warning of volcanic tsunamis remain challenging (further technical and scientific developments being necessary) and must be coupled with policies of population preparedness. © 2015 The Author(s).

  10. Engineering a robotic approach to mapping exposed volcanic fissures

    Science.gov (United States)

    Parcheta, C. E.; Parness, A.; Mitchell, K. L.

    2014-12-01

    Field geology provides a framework for advanced computer models and theoretical calculations of volcanic systems. Some field terrains, though, are poorly preserved or accessible, making documentation, quantification, and investigation impossible. Over 200 volcanologists at the 2012 Kona Chapman Conference on volcanology agreed that and important step forward in the field over the next 100 years should address the realistic size and shape of volcanic conduits. The 1969 Mauna Ulu eruption of Kīlauea provides a unique opportunity to document volcanic fissure conduits, thus, we have an ideal location to begin addressing this topic and provide data on these geometries. Exposed fissures can be mapped with robotics using machine vision. In order to test the hypothesis that fissures have irregularities with depth that will influence their fluid dynamical behavior, we must first map the fissure vents and shallow conduit to deci- or centimeter scale. We have designed, constructed, and field-tested the first version of a robotic device that will image an exposed volcanic fissure in three dimensions. The design phase included three steps: 1) create the payload harness and protective shell to prevent damage to the electronics and robot, 2) construct a circuit board to have the electronics communicate with a surface-based computer, and 3) prototype wheel shapes that can handle a variety of volcanic rock textures. The robot's mechanical parts were built using 3d printing, milling, casting and laser cutting techniques, and the electronics were assembled from off the shelf components. The testing phase took place at Mauna Ulu, Kīlauea, Hawai'i, from May 5 - 9, 2014. Many valuable design lessons were learned during the week, and the first ever 3D map from inside a volcanic fissure were successfully collected. Three vents had between 25% and 95% of their internal surfaces imaged. A fourth location, a non-eruptive crack (possibly a fault line) had two transects imaging the textures

  11. Satellite data-relay activities in Arizona

    Science.gov (United States)

    Boner, F.C.; Blee, J.W.; Shope, W.G.

    1985-01-01

    The U.S. Geological Survey (USGS) Arizona District collects data from automated streamflow stations for a wide variety of uses. Data from these stations are provided to Federal, State, and local agencies that have a responsibility to issue flood warnings; to generate forecasts of water availability; to monitor flow to insure compliance with treaties and other legal mandates; and to manage reservoirs for hydropower, flood abatement, and municipal and irrigation water supply. In the mid-1970's, the escalation of data collection costs and a need for more timely data led the Arizona District to examine alternatives for remote data acquisition. On the basis of successful data communications experiments with NASA 's Landsat satellite, an operational system for satellite-data relay was developed in 1976 using the National Oceanic and Atmospheric Administrations 's (NOAA) Geostationary Operational Environmental Satellite (GOES). A total of 62 data collection platforms (DCP's) was operated in 1983. Satellite telemetry operations are controlled at the remote data-collection stations by small battery-operated data collection platforms. The DCP 's periodically collect data from the sensors, store the data in computer memory, and at preset times transmit the data to the GOES satellite. The satellite retransmits the data to Earth where a ground-receive station transmits or transfers the data by land communications to the USGS computer in Reston, Virginia, for processing. The satellite relay transfers the data from sensor to computer in minutes; therefore, the data are available to users on a near real-time basis. (Author 's abstract)

  12. Reevaluation of the Crooked Ridge River- Early Pleistocene (ca. 2 Ma) age and origin of the White Mesa Alluvium, northeastern Arizona

    Science.gov (United States)

    Hereford, Richard; Beard, Sue; Dickinson, William R.; Karlstrom, Karl E.; Heizler, Matthew T.; Crossey, Laura J.; Amoroso, Lee; House, Kyle; Pecha, Mark

    2016-01-01

    Essential features of the previously named and described Miocene Crooked Ridge River in northeastern Arizona (USA) are reexamined using new geologic and geochronologic data. Previously it was proposed that Cenozoic alluvium at Crooked Ridge and southern White Mesa was pre–early Miocene, the product of a large, vigorous late Paleogene river draining the 35–23 Ma San Juan Mountains volcanic field of southwestern Colorado. The paleoriver probably breeched the Kaibab uplift and was considered important in the early evolution of the Colorado River and Grand Canyon. In this paper, we reexamine the character and age of these Cenozoic deposits. The alluvial record originally used to propose the hypothetical paleoriver is best exposed on White Mesa, providing the informal name White Mesa alluvium. The alluvium is 20–50 m thick and is in the bedrock-bound White Mesa paleovalley system, which comprises 5 tributary paleochannels. Gravel composition, detrital zircon data, and paleochannel orientation indicate that sediment originated mainly from local Cretaceous bedrock north, northeast, and south of White Mesa. Sedimentologic and fossil evidence imply alluviation in a low-energy suspended sediment fluvial system with abundant fine-grained overbank deposits, indicating a local channel system rather than a vigorous braided river with distant headwaters. The alluvium contains exotic gravel clasts of Proterozoic basement and rare Oligocene volcanic clasts as well as Oligocene–Miocene detrital sanidine related to multiple caldera eruptions of the San Juan Mountains and elsewhere. These exotic clasts and sanidine likely came from ancient rivers draining the San Juan Mountains. However, in this paper we show that the White Mesa alluvium is early Pleistocene (ca. 2 Ma) rather than pre–early Miocene. Combined 40Ar/39Ar dating of an interbedded tuff and detrital sanidine ages show that the basal White Mesa alluvium was deposited at 1.993 ± 0.002 Ma, consistent with a detrital

  13. Field Geologic Observation and Sample Collection Strategies for Planetary Surface Exploration: Insights from the 2010 Desert RATS Geologist Crewmembers

    Science.gov (United States)

    Hurtado, Jose M., Jr.; Young, Kelsey; Bleacher, Jacob E.; Garry, W. Brent; Rice, James W., Jr.

    2012-01-01

    Observation is the primary role of all field geologists, and geologic observations put into an evolving conceptual context will be the most important data stream that will be relayed to Earth during a planetary exploration mission. Sample collection is also an important planetary field activity, and its success is closely tied to the quality of contextual observations. To test protocols for doing effective planetary geologic field- work, the Desert RATS(Research and Technology Studies) project deployed two prototype rovers for two weeks of simulated exploratory traverses in the San Francisco volcanic field of northern Arizona. The authors of this paper represent the geologist crew members who participated in the 2010 field test.We document the procedures adopted for Desert RATS 2010 and report on our experiences regarding these protocols. Careful consideration must be made of various issues that impact the interplay between field geologic observations and sample collection, including time management; strategies relatedtoduplicationofsamplesandobservations;logisticalconstraintson the volume and mass of samples and the volume/transfer of data collected; and paradigms for evaluation of mission success. We find that the 2010 field protocols brought to light important aspects of each of these issues, and we recommend best practices and modifications to training and operational protocols to address them. Underlying our recommendations is the recognition that the capacity of the crew to flexibly execute their activities is paramount. Careful design of mission parameters, especially field geologic protocols, is critical for enabling the crews to successfully meet their science objectives.

  14. Volcanism and associated hazards: The Andean perspective

    Science.gov (United States)

    Tilling, R.I.

    2009-01-01

    Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years) than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions") recognized worldwide that have occurred from the Ordovician to the Pleistocene. The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru). The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars) were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (volcano risk in the Andean region. But much remains to be done.

  15. Disruptive event analysis: volcanism and igneous intrusion

    Energy Technology Data Exchange (ETDEWEB)

    Crowe, B.M.

    1980-08-01

    An evaluation is made of the disruptive effects of volcanic activity with respect to long term isolation of radioactive waste through deep geologic storage. Three major questions are considered. First, what is the range of disruption effects of a radioactive waste repository by volcanic activity. Second, is it possible, by selective siting of a repository, to reduce the risk of disruption by future volcanic activity. And third, can the probability of repository disruption by volcanic activity be quantified. The main variables involved in the evaluation of the consequences of repository disruption by volcanic activity are the geometry of the magma-repository intersection (partly controlled by depth of burial) and the nature of volcanism. Potential radionuclide dispersal by volcanic transport within the biosphere ranges in distance from several kilometers to global. Risk from the most catastrophic types of eruptions can be reduced by careful site selection to maximize lag time prior to the onset of activity. Certain areas or volcanic provinces within the western United States have been sites of significant volcanism and should be avoided as potential sites for a radioactive waste repository. Examples of projection of future sites of active volcanism are discussed for three areas of the western United States. Probability calculations require two types of data: a numerical rate or frequency of volcanic activity and a numerical evaluation of the areal extent of volcanic disruption for a designated region. The former is clearly beyond the current state of art in volcanology. The latter can be approximated with a reasonable degree of satisfaction. In this report, simplified probability calculations are attempted for areas of past volcanic activity.

  16. On the visibility of airborne volcanic ash and other aerosols from the pilot's perspective in flight

    Science.gov (United States)

    Weinzierl, B.; Sauer, D.; Minikin, A.; Reitebuch, O.; Dahlkötter, F.; Mayer, B.; Emde, C.; Tegen, I.; Gasteiger, J.; Petzold, A.; Veira, A.; Kueppers, U.; Schumann, U.

    2012-04-01

    . An uninformed observer is unlikely to recognize an aged volcanic ash layer in his field of view without further information. The presence of clouds would make it even more complicated to visually detect volcanic ash. Clouds can either directly block the direct sight to the ash layer or reduce the contrast if present in the background.

  17. Recent advances in ground-based ultraviolet remote sensing of volcanic SO2 fluxes

    Directory of Open Access Journals (Sweden)

    Euripides P. Kantzas

    2011-06-01

    Full Text Available Measurements of volcanic SO2 emission rates have been the mainstay of remote-sensing volcanic gas geochemistry for almost four decades, and they have contributed significantly to our understanding of volcanic systems and their impact upon the atmosphere. The last ten years have brought step-change improvements in the instrumentation applied to these observations, which began with the application of miniature ultraviolet spectrometers that were deployed in scanning and traverse configurations, with differential optical absorption spectroscopy evaluation routines. This study catalogs the more recent empirical developments, including: ultraviolet cameras; wide-angle field-of-view differential optical absorption spectroscopy systems; advances in scanning operations, including tomography; and improved understanding of errors, in particular concerning radiative transfer. Furthermore, the outcomes of field deployments of sensors during the last decade are documented, with respect to improving our understanding of volcanic dynamics and degassing into the atmosphere.

  18. Contaminants in fish and wildlife of Lynx Lake, Arizona

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Sediment, water, crayfish, and fish were collected at Lynx Creek and Lynx Lake, Arizona in 2004 and 2005. Granite Basin Lake was used as a reference site. Both sites...

  19. Ignition interlock : an investigation into rural Arizona judges’ perceptions.

    Science.gov (United States)

    2014-05-01

    This study sought to answer several questions regarding 2007 Arizona legislation requiring ignition interlock for all offenders convicted of Driving-Under-the-Influence (DUI), including first time DUI offenders. At the time the law was passed, Arizon...

  20. The Tree Lines at Pipe Spring National Monument, Arizona (treeline)

    Data.gov (United States)

    National Park Service, Department of the Interior — This is an Arc/Info coverage consisting of 7 arcs representing the tree lines at Pipe Spring National Monument, Arizona. The tree lines were collected by a Trimble...

  1. 76 FR 18777 - State of Arizona Resource Advisory Council Meetings

    Science.gov (United States)

    2011-04-05

    ...) recreation fee proposals in Arizona. The RRAC will not review any recreation fee proposals at this meeting... meeting. Under the Federal Lands Recreation Enhancement Act, the RAC has been designated as the Recreation...

  2. Uranium potential in Precambrian conglomerates of the Central Arizona Arch. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, P.; Wirth, K.R.

    1981-01-01

    The Precambrian quartz-pebble conglomerates in a 9500 km/sup 2/ area of central Arizona between the Mazatzal and Sierra Ancha Mountains were investigated for the presence of significant uranium concentrations or environments favorable for uranium concentration. Abundant conglomerates are found in either the 1740 to 1720 m.y.-old Alder Group, the 1700 m.y.-old Mazatzal Group, or the 1300 to 1250 m.y.-old Apache Group. Supplementing detailed geologic study of the conglomerates is a systematic analysis of major-element, trace-element, and uranium-geochemical data for over 300 rock samples. This analysis provides a relationship between scintillometer data and uranium content for different rock types and gives correlation coefficients between uranium and related metals in the heavy-mineral assemblage. A radiometric variance plot of averages for the various conglomerate types shows that Apache Group conglomerates are Th-rich and too evolved, marine Mazatzal and Alder conglomerates are U-poor, whereas only high-energy fluvial environments in basal Deadman and Mazatzal conglomerates strongly concentrated uranium values. Reevaluation of accepted criteria for uranium concentration in Precambrian quartz-pebble conglomerates in light of new data on uranium-mineral stability under nonreducing conditions and new observations on major world deposits leads to the conclusion that the presence of a U-rich source terrain is singularly the most important factor in finding a conglomeratic uranium deposit. Most Precambrian conglomerates of the world contain depositional environments and heavy mineral concentrates conducive to uranium concentration, but insufficient uranium is present in the source. The reason pyritic, carbonaceous siltstones in the Apache Group of central Arizona contain stratabound uranium deposits is that a nearby U-rich source of high K/sub 2/O rhyolitic volcanism was available during deposition of the siltstones.

  3. The migration response to the Legal Arizona Workers Act

    OpenAIRE

    Ellis, Mark; Wright, Richard; Townley, Matthew; Copeland, Kristy

    2014-01-01

    The 2008 Legal Arizona Workers Act (LAWA) requires all public and private employers to authenticate the legal status of their workers using the federal employment verification system known as E-Verify. With LAWA, Arizona became the first state to have a universal mandate for employment verification. While LAWA targets unauthorized workers, most of whom are Latino immigrants, other groups could experience LAWA’s effects, such as those who share households with undocumented workers. In addition...

  4. Arizona law enforcement biometrics identification and information sharing technology framework

    OpenAIRE

    Kalaf, William M.

    2010-01-01

    CHDS State/Local Approved for public release; distribution is unlimited Since 9/11, Arizona and federal law enforcement agencies understand the need to improve subject identification capabilities and integrate criminal information across jurisdictions. Agencies still collect information based on a subject's name and demographics for identification. Using a subject's name and demographics as keys to identifying information is a weakness. In 2012, Arizona will upgrade the state's strat...

  5. DOE-University of Arizona Faculty Development Project. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Fillerup, Joseph M.

    1980-09-08

    The DOE-University of Arizona Faculty Development Project on Energy successfully completed a faculty development program. There were three phases of the program consisting of: a three week energy workshop for teachers, participation and cooperation with Students for Safe Energy in presentation of an Alternative Energy Festival at the University of Arizona, and workshops for teachers conducted at Flowing Wells School District. Each of these is described. Attendees are listed and a director's evaluation of the workshop is given.

  6. Burfellshraun - a terrestrial analogue to recent volcanism on mars

    DEFF Research Database (Denmark)

    Haack, Henning; Dall, Jørgen; Rossi, Matti

    2004-01-01

    of the Martian flows. Up to km-sized plates have flowed several km downsteam from the vent area. Our remote sensing studies and field work suggest that the type of eruption seen in Burfellshraun can be found nowhere else on Earth. The only similar lava flows that we have found are those on Mars. Our study...... of the formation of Burfellshraun provides new constraints and insight into the extensive recent volcanic activity on Mars....

  7. Evidence of Multiple Flank Collapse at Volcan Baru, Panama

    Science.gov (United States)

    Herrick, J. A.; Rose, W. I.

    2009-12-01

    Michigan Tech's Peace Corps Master's International program (PCMI) in Geological Hazards has enabled several long-term investigations of active volcanoes in Latin America. To contribute to volcanic hazard assessments in Panama and achieve the goals defined by the PCMI program, we developed this debris avalanche project to address outstanding questions regarding Volcan Baru's most devastating event - massive slope failure of the western flank. Relying on basic mapping tools as well as the 2007 USGS Open-File Report focusing on hazard assessments of Panama's youngest and potentially active volcano, identification of the debris avalanche deposits (DAD) required detailed field investigations to determine the limits of the units. Extending across an area larger than 600 km2, field strategies were developed based on outcrop exposures within drainages and road-cuts. Aerial photos and DEMs of Baru's nested craters were interpreted by earlier scientists as the remains of two collapsed flanks. The results from in-depth field traverses provide several important discoveries: paleosols and sharp contacts within the stratigraphy indicate multiple DAD, deeply weathered hummocks red-flag the deposits more than 50-km away from Baru's crater, and high-quality radiocarbon samples (up to 45-cm long fragments of entrained wood) lie in the distal reaches of the debris flow area. During the 2008-2009 field seasons, we received assistance from the University of Panama, Civil Protection, and Panama's National Institute of Geography. Support from local experts and feedback from professional scientists of the Smithsonian Institution and Costa Rica's Institute of Electricity were invaluable. The 2-year investment in volcanic hazard studies has brought together resources from several countries as well as fresh data that will benefit the residents and emergency management officials of Panama. Jigsaw fractured clasts lie within Volcan Baru's debris avalanche deposits more than 28 km south of the

  8. Soil compaction vulnerability at Organ Pipe Cactus National Monument, Arizona

    Science.gov (United States)

    Webb, Robert H.; Nussear, Kenneth E.; Carmichael, Shinji; Esque, Todd C.

    2014-01-01

    Compaction vulnerability of different types of soils by hikers and vehicles is poorly known, particularly for soils of arid and semiarid regions. Engineering analyses have long shown that poorly sorted soils (for example, sandy loams) compact to high densities, whereas well-sorted soils (for example, eolian sand) do not compact, and high gravel content may reduce compaction. Organ Pipe Cactus National Monument (ORPI) in southwestern Arizona, is affected greatly by illicit activities associated with the United States–Mexico border, and has many soils that resource managers consider to be highly vulnerable to compaction. Using geospatial soils data for ORPI, compaction vulnerability was estimated qualitatively based on the amount of gravel and the degree of sorting of sand and finer particles. To test this qualitative assessment, soil samples were collected from 48 sites across all soil map units, and undisturbed bulk densities were measured. A scoring system was used to create a vulnerability index for soils on the basis of particle-size sorting, soil properties derived from Proctor compaction analyses, and the field undisturbed bulk densities. The results of the laboratory analyses indicated that the qualitative assessments of soil compaction vulnerability underestimated the area of high vulnerability soils by 73 percent. The results showed that compaction vulnerability of desert soils, such as those at ORPI, can be quantified using laboratory tests and evaluated using geographic information system analyses, providing a management tool that managers potentially could use to inform decisions about activities that reduce this type of soil disruption in protected areas.

  9. Volcanic caves of East Africa - an overview

    OpenAIRE

    Jim W. Simons

    1998-01-01

    Numerous Tertiary to recent volcanoes are located in East Africa. Thus, much of the region is made up volcanic rock, which hosts the largest and greatest variety of East Africas caves. Exploration of volcanic caves has preoccupied members of Cave Exploration Group of East Africa (CEGEA) for the past 30 years. The various publications edited by CEGEA are in this respect a treasure troves of speleological information. In the present paper an overview on the most important volcanic caves and are...

  10. Tools and Technologies Needed for Conducting Planetary Field Geology While On EVA: Insights from the 2010 Desert RATS Geologist Crewmembers

    Science.gov (United States)

    Young, Kelsey; Hurtado, Jose M., Jr.; Bleacher, Jacob E.; Garry, W. Brent; Bleisath, Scott; Buffington, Jesse; Rice, James W., Jr.

    2011-01-01

    Observation is the primary role of all field geologists, and geologic observations put into an evolving conceptual context will be the most important data stream that will be relayed to Earth during a planetary exploration mission. Sample collection is also an important planetary field activity, and its success is closely tied to the quality of contextual observations. To test protocols for doing effective planetary geologic fieldwork, the Desert RATS (Research and Technology Studies) project deployed two prototype rovers for two weeks of simulated exploratory traverses in the San Francisco volcanic field of northern Arizona. The authors of this paper represent the geologist crewmembers who participated in the 2010 field test. We document the procedures adopted for Desert RATS 2010 and report on our experiences regarding these protocols. Careful consideration must be made of various issues that impact the interplay between field geologic observations and sample collection, including time management; strategies related to duplication of samples and observations; logistical constraints on the volume and mass of samples and the volume/transfer of data collected; and paradigms for evaluation of mission success. We find that the 2010 field protocols brought to light important aspects of each of these issues, and we recommend best practices and modifications to training and operational protocols to address them. Underlying our recommendations is the recognition that the capacity of the crew to "flexibly execute" their activities is paramount. Careful design of mission parameters, especially field geologic protocols, is critical for enabling the crews to successfully meet their science objectives.

  11. Detecting Volcanic Ash Plumes with GNSS Signals

    Science.gov (United States)

    Rainville, N.; Larson, K. M.; Palo, S. E.; Mattia, M.; Rossi, M.; Coltelli, M.; Roesler, C.; Fee, D.

    2016-12-01

    Global Navigation Satellite Systems (GNSS) receivers are commonly placed near volcanic sites to measure ground deformation. In addition to the carrier phase data used to measure ground position, these receivers also record Signal to Noise ratio (SNR) data. Larson (2013) showed that attenuations in SNR data strongly correlate with ash emissions at a series of eruptions of Redoubt Volcano. This finding has been confirmed at eruptions for Tongariro, Mt Etna, Mt Shindake, and Sakurajima. In each of these detections, very expensive geodetic quality GNSS receivers were used. If low-cost GNSS instruments could be used instead, a networked array could be deployed and optimized for plume detection and tomography. The outputs of this sensor array could then be used by both local volcanic observatories and Volcano Ash Advisory Centers. Here we will describe progress in developing such an array. The sensors we are working with are intended for navigation use, and thus lack the supporting power and communications equipment necessary for a networked system. Reliably providing those features is major challenge for the overall sensor design. We have built prototypes of our Volcano Ash Plume Receiver (VAPR), with solar panels, lithium-ion batteries and onboard data storage for preliminary testing. We will present results of our field tests of both receivers and antennas. A second critical need for our array is a reliable detection algorithm. We have tested our algorithm on data from recent eruptions and have incorporated the noise characteristics of the low-cost GNSS receiver. We have also developed a simulation capability so that the receivers can be deployed to optimize vent crossing GNSS signals.

  12. Professional conduct of scientists during volcanic crises

    Science.gov (United States)

    IAVCEI SubcommitteeCrisis Protocols; Newhall, Chris; Aramaki, Shigeo; Barberi, Franco; Blong, Russell; Calvache, Marta; Cheminee, Jean-Louis; Punongbayan, Raymundo; Siebe, Claus; Simkin, Tom; Sparks, Stephen; Tjetjep, Barry; Newhall, Chris

    Stress during volcanic crises is high, and any friction between scientists can distract seriously from both humanitarian and scientific effort. Friction can arise, for example, if team members do not share all of their data, if differences in scientific interpretation erupt into public controversy, or if one scientist begins work on a prime research topic while a colleague with longer-standing investment is still busy with public safety work. Some problems arise within existing scientific teams; others are brought on by visiting scientists. Friction can also arise between volcanologists and public officials. Two general measures may avert or reduce friction: (a) National volcanologic surveys and other scientific groups that advise civil authorities in times of volcanic crisis should prepare, in advance of crises, a written plan that details crisis team policies, procedures, leadership and other roles of team members, and other matters pertinent to crisis conduct. A copy of this plan should be given to all current and prospective team members. (b) Each participant in a crisis team should examine his or her own actions and contribution to the crisis effort. A personal checklist is provided to aid this examination. Questions fall generally in two categories: Are my presence and actions for the public good? Are my words and actions collegial, i.e., courteous, respectful, and fair? Numerous specific solutions to common crisis problems are also offered. Among these suggestions are: (a) choose scientific team leaders primarily for their leadership skills; (b) speak publicly with a single scientific voice, especially when forecasts, warnings, or scientific disagreements are involved; (c) if you are a would-be visitor, inquire from the primary scientific team whether your help would be welcomed, and, in general, proceed only if the reply is genuinely positive; (d) in publications, personnel evaluations, and funding, reward rather than discourage teamwork. Models are

  13. Electrochemical sensor monitoring of volcanic gases

    Science.gov (United States)

    Roberts, Tjarda; Freshwater, Ray; Oppenheimer, Clive; Saffell, John; Jones, Rod; Griffiths, Paul; Braban, Christine; Mead, Iqbal

    2010-05-01

    Advances in instrumentation have fuelled a recent growth of interest in using portable sensor systems for environmental monitoring of pollution. Developments in wireless technology are enabling such systems to operate remotely and autonomously, generating a wealth of environmental data. We report here on the application of miniature Alphasense electrochemical sensors to the detection and characterisation of gases in volcanic plumes. A highly portable sensor system was developed to operate an array of 6 low cost electrochemical sensors to detect CO, H2, HCl, SO2, H2S and NO2 at 1 Hz. A miniature pump draws air over all sensors simultaneously (i.e. sensors arranged in parallel). The sensor output in these campaigns was logged on PDAs for real-time viewing, and later download (with a view to future data-streaming). The instrument was deployed at a number of volcanoes and was subject to extremely harsh conditions including highly acidic environments, low (Antarctic) temperatures, and transport over rough terrain. Analysis methods are demonstrated that consider calibration, cross-sensitivities of the sensors to multiple gases, differing sensor response times, temperature dependence, and background sensor drift with time. The analysis is applied to a range of plume field-measurements to extract gas concentrations ranging from 100's ppmv to sub-ppmv and to characterise the individual volcano emissions. Applications of similar sensor systems for real-time long-term monitoring of volcanic emissions (which may indicate and ultimately predict eruptive behavior), and UAV and balloon-borne plume sampling are now already being realised. This work focused on demonstrating the application of electrochemical sensors to monitoring of environmental pollution from volcanoes. Other applications for similar sensors include the near-source monitoring of industrial emissions, and of pollutant levels enhanced by traffic emissions in the urban environment.

  14. Noachian Martian Volcanics a Water Source

    Science.gov (United States)

    Zent, A. P.; Glaze, L. S.; Baloga, S. M.; Fonda, Mark (Technical Monitor)

    2002-01-01

    H2O was supplied to the Noachian atmosphere by eruptions, or in association with large impacts. Most water outgassed into an extremely cold atmosphere, and condensate deposits were inevitable. High heat flow could lead to subglacial melting only if ice thicknesses were greater than 500-1000m, which is extremely unlikely. Subareal melting and flow is contingent upon temperatures periodically exceeding 273 K, and retarding evaporative loss of the flow. In still air, evaporation into a dry atmosphere is in the free convection regime, and a stream with 2 cu m/s discharge, flowing 1 m/s could persist for hundreds of days and cover distances greater than any valley reach. The zero-wind-shear condition is considered implausible however. We investigate the possibility that evaporation rates were suppressed because the atmosphere was regionally charged with H2O as it moved over snow/ice fields. Our initial concern is precipitation from volcanic plumes. A Kilauea-style eruption on the martian surface would cover a 10km circular deposit with 10cm of H2O, if all H2O could be precipitated near the vent. The characteristics of the eruption at the vent, (vent size, temperature, H2O content, etc.) are independent of the environmental conditions. The subsequent behavior of the plume, including precipitation of ash and H2O condensate depends strongly on the environment. Hence, the proximal fate of volcanic H2O is amenable to treatment in a model. A simple bulk thermodynamic model of the rise of an H2O plume through a stably stratified CO2 atmosphere, with only adiabatic cooling, produces runaway plume rise. A more complex treatment includes the effects of latent heat release, wind shear along the plume, divergence of ash and H2O, and will yield more realistic estimates of H2O transport in eruptive plumes. Results of these simulations will be presented.

  15. Nephelometric Dropsonde for Volcanic Ash Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced dropsondes that could effectively be guided through atmospheric regions of interest such as volcanic plumes could enable unprecedented observations of...

  16. Felsic Volcanics on the Moon

    Science.gov (United States)

    Jolliff, B. L.; Lawrence, S. J.; Stopar, J.; Braden, S.; Hawke, B. R.; Robinson, M. S.; Glotch, T. D.; Greenhagen, B. T.; Seddio, S. M.

    2012-12-01

    Lunar Reconnaissance Orbiter (LRO) imaging and thermal data provide new morphologic and compositional evidence for features that appear to be expressions of nonmare silicic volcanism. Examples reflecting a range of sizes and volcanic styles include the Gruithuisen and Mairan Domes, and the Hansteen Alpha (H-A) and Compton-Belkovich (C-B) volcanic complexes. In this work we combine new observations with existing compositional remote sensing and Apollo sample data to assess possible origins. Images and digital topographic data at 100 m scale (Wide Angle Camera) and ~0.5 to 2 m (Narrow Angle Camera) reveal (1) slopes on volcanic constructs of ~12° to 27°, (2) potential endogenic summit depressions, (3) small domical features with dense boulder populations, and (4) irregular collapse features. Morphologies in plan view range from the circular to elliptical Gruithuisen γ and δ domes (~340 km2 each), to smaller cumulodomes such as Mairan T and C-B α (~30 km2, each), to the H-A (~375 km2) and C-B (~680 km2) volcanic complexes. Heights range from ~800-1800 m, and most domes are relatively flat-topped or have a central depression. Positions of the Christiansen Feature in LRO Diviner data reflect silicic compositions [1]. Clementine UVVIS-derived FeO varies from ~5 to 10 wt%. Lunar Prospector Th data indicate model values of 20-55 ppm [2,3], which are consistent with compositions ranging from KREEP basalt to lunar granite. The Apollo collection contains small rocks and breccia clasts of felsic/granitic lithologies. Apollo 12 samples include small, pristine and brecciated granitic rock fragments and a large, polymict breccia (12013) consisting of felsic material (quartz & K-feldspar-rich) and mafic phases (similar to KREEP basalt). Many of the evolved lunar rocks have geochemically complementary compositions. The lithologic associations and the lack of samples with intermediate composition suggest a form of magmatic differentiation that produced mafic and felsic

  17. Using high-precision 40Ar/39Ar geochronology to understand volcanic hazards within the Rio Grande rift and along the Jemez lineament, New Mexico

    Science.gov (United States)

    Zimmerer, M. J.; McIntosh, W. C.; Heizler, M. T.; Lafferty, J.

    2014-12-01

    High-precision Ar/Ar ages were generated for late Quaternary volcanic fields in the Rio Grande rift and along the Jemez Lineament, New Mexico, to assess the time-space patterns of volcanism and begin quantifying volcanic hazards for the region. The published chronology of most late Quaternary volcanic centers in the region is not sufficiently precise, accurate, or complete for a comprehensive volcanic hazard assessment. Ar/Ar ages generated as part of this study were determined using the high-sensitivity, multi-collector ARGUS VI mass spectrometer, which provides about an order of magnitude more precise isotopic measurements compared to older generation, single-detector mass spectrometers. Ar/Ar ages suggest an apparent increase in eruption frequency during the late Quaternary within the Raton-Clayton volcanic field, northeastern NM. Only four volcanoes erupted between 426±8 and 97±3 ka. Contrastingly, four volcanoes erupted between 55±2 and 32±5 ka. This last eruptive phase displays a west to east migration of volcanism, has repose periods of 0 to 17 ka, and an average recurrence rate of 1 eruption per 5750 ka. The Zuni-Bandera volcanic field, west-central NM, is composed of the ~100 late Quaternary basaltic vents. Preliminary results suggest that most of the Chain of Craters, the largest and oldest part of the Zuni-Bandera field, erupted between ~100 and 250 ka. Volcanism then migrated to the east, where published ages indicate at least seven eruptions between 50 and 3 ka. Both volcanic fields display a west to east migration of volcanism during the last ~500 ka, although the pattern is more pronounced in the Zuni-Bandera field. A reassessment of low-precision published ages for other late Quaternary volcanic fields in region indicates that most fields display a similar west to east migration of volcanism during the last ~500 ka. One possible mechanism to explain the observed patterns of volcanism is the westward migration of the North American plate relative

  18. Volcanism in slab tear faults is larger than in island-arcs and back-arcs.

    Science.gov (United States)

    Cocchi, Luca; Passaro, Salvatore; Tontini, Fabio Caratori; Ventura, Guido

    2017-11-13

    Subduction-transform edge propagators are lithospheric tears bounding slabs and back-arc basins. The volcanism at these edges is enigmatic because it is lacking comprehensive geological and geophysical data. Here we present bathymetric, potential-field data, and direct observations of the seafloor on the 90 km long Palinuro volcanic chain overlapping the E-W striking tear of the roll-backing Ionian slab in Southern Tyrrhenian Sea. The volcanic chain includes arc-type central volcanoes and fissural, spreading-type centers emplaced along second-order shears. The volume of the volcanic chain is larger than that of the neighbor island-arc edifices and back-arc spreading center. Such large volume of magma is associated to an upwelling of the isotherms due to mantle melts upraising from the rear of the slab along the tear fault. The subduction-transform edge volcanism focuses localized spreading processes and its magnitude is underestimated. This volcanism characterizes the subduction settings associated to volcanic arcs and back-arc spreading centers.

  19. Landscape evolution within a retreating volcanic arc, Costa Rica, Central America

    Science.gov (United States)

    Marshall, Jeffrey S.; Idleman, Bruce D.; Gardner, Thomas W.; Fisher, Donald M.

    2003-05-01

    Subduction of hotspot-thickened seafloor profoundly affects convergent margin tectonics, strongly affecting upper plate structure, volcanism, and landscape evolution. In southern Central America, low-angle subduction of the Cocos Ridge and seamount domain largely controls landscape evolution in the volcanic arc. Field mapping, stratigraphic correlation, and 40Ar/39Ar geochronology for late Cenozoic volcanic rocks of central Costa Rica provide new insights into the geomorphic response of volcanic arc landscapes to changes in subduction parameters (slab thickness, roughness, dip). Late Neogene volcanism was focused primarily along the now-extinct Cordillera de Aguacate. Quaternary migration of the magmatic front shifted volcanism northeastward to the Caribbean slope, creating a new topographic divide and forming the Valle Central basin. Stream capture across the paleo Aguacate divide led to drainage reversal toward the Pacific slope and deep incision of reorganized fluvial networks. Pleistocene caldera activity generated silicic ash flows that buried the Valle Central and descended the Tárcoles gorge to the Orotina debris fan at the coast. Growth of the modern Cordillera Central accentuated relief along the new divide, establishing the Valle Central as a Pacific slope drainage basin. Arc migration, relocation of the Pacific-Caribbean drainage divide, and formation of the Valle Central basin resulted from slab shallowing as irregular, hotspot-thickened crust entered the subduction zone. The geomorphic evolution of volcanic arc landscapes is thus highly sensitive to changes in subducting plate character.

  20. Volcanic hazards and public response

    Science.gov (United States)

    Peterson, Donald W.

    1988-05-01

    Although scientific understanding of volcanoes is advancing, eruptions continue to take a substantial toll of life and property. Some of these losses could be reduced by better advance preparation, more effective flow of information between scientists and public officials, and better understanding of volcanic behavior by all segments of the public. The greatest losses generally occur at volcanoes that erupt infrequently where people are not accustomed to dealing with them. Scientists sometimes tend to feel that the blame for poor decisions in emergency management lies chiefly with officials or journalists because of their failure to understand the threat. However, the underlying problem embraces a set of more complex issues comprising three pervasive factors. The first factor is the volcano: signals given by restless volcanoes are often ambiguous and difficult to interpret, especially at long-quiescent volcanoes. The second factor is people: people confront hazardous volcanoes in widely divergent ways, and many have difficulty in dealing with the uncertainties inherent in volcanic unrest. The third factor is the scientists: volcanologists correctly place their highest priority on monitoring and hazard assessment, but they sometimes fail to explain clearly their conclusions to responsible officials and the public, which may lead to inadequate public response. Of all groups in society, volcanologists have the clearest understanding of the hazards and vagaries of volcanic activity; they thereby assume an ethical obligation to convey effectively their knowledge to benefit all of society. If society resists, their obligation nevertheless remains. They must use the same ingenuity and creativity in dealing with information for the public that they use in solving scientific problems. When this falls short, even excellent scientific results may be nullified.

  1. Geologic map of the Fredonia 30' x 60' quadrangle, Mohave and Coconino counties, northern Arizona

    Science.gov (United States)

    Billingsley, George H.; Priest, Susan S.; Felger, Tracey J.

    2008-01-01

    This geologic map is the result of a cooperative effort of the U.S. Geological Survey, the National Park Service, the U.S. Forest Service, and the Bureau of Land Management (BLM) and the Kaibab-Paiute Tribe to provide a regional geologic database for resource management officials of all government and agencies, city municipalities, private enterprises, and individuals of this part of the Arizona Strip. The Arizona Strip is part of northwestern Arizona north of the Colorado River and bounded by the States of Nevada and Utah. Field work on the Kaibab-Paiute Indian Reservation was conducted from 2002 to 2005 with permission from the Kaibab-Paiute Tribal Government of that administration and permission was granted to publish a geologic map of 4 quadrangles online (Billingsley and others, 2004). The Kaibab-Paiute Tribal government of 2006 to 2008 requested that all geologic information within the Kaibab-Paiute Indian Reservation not be published as part of the Fredonia 30' x 60' quadrangle (this publication). For further information, contact the Kaibab-Paiute Tribal government at HC 65 Box 2, Fredonia, Arizona, 86022, telephone # (928) 643-7245. Visitors to the Kaibab-Paiute Indian Reservation are required to obtain a permit and permission for access from the Tribal Offices at the junction of State Highway 389 and the paved road leading to Pipe Spring National Monument. The Fredonia 30' x 60' quadrangle encompasses approximately 5,018 km2 (1,960 mi2) within Mohave and Coconino Counties, northern Arizona and is bounded by longitude 112 deg to 113 deg W., and latitude 36 deg 30' to 37 deg N. The map area lies within the southern Colorado Plateaus geologic province (herein Colorado Plateau). The map area is locally subdivided into seven physiographic parts: the Grand Canyon (Kanab Canyon and its tributaries), Kanab Plateau, Uinkaret Plateau, Kaibab Plateau, Paria Plateau, House Rock Valley, and Moccasin Mountains as defined by Billingsley and others, 1997, (fig. 1

  2. The impact of the characteristics of volcanic ash on forecasting.

    Science.gov (United States)

    Beckett, Frances; Hort, Matthew; Millington, Sarah; Stevenson, John; Witham, Claire

    2013-04-01

    The eruption of Eyjafjallajökull during April - May 2010 and Grímsvötn in May 2011, Iceland, caused the widespread dispersion of volcanic ash across the NE Atlantic, and ultimately into UK and European airspace. This resulted in thousands of flights to and from affected countries across Europe to be cancelled. The Met Office, UK, is the home of the London VAAC, a Volcanic Ash Advisory Centre, and as such is responsible for providing reports and forecasts for the movement of volcanic ash clouds covering the UK, Iceland and the north-eastern part of the North Atlantic ocean. To forecast the dispersion of volcanic ash requires that the sedimentation of ash particles through the atmosphere is effectively modelled. The settling velocity of an ash particle is a function of its size, shape and density, plus the density and viscosity of the air through which it is falling. We consider the importance of characterising the physical properties of ash when modelling the long range dispersion of ash particles through the atmosphere. Using the Reynolds number dependent scheme employed by NAME, the Lagrangian particle model used operationally by the Met Office, we calculate the settling velocity and thus the maximum travel distance of an ash particle through an idealised atmosphere as a function of its size, shape and density. The results are compared to measured particle sizes from deposits across Europe following the eruption of Eyjafjallajökull in 2010. Further, the particle size distribution (PSD) of ash in a volcanic cloud with time is modelled using NAME: the particle density distribution and particle shape factor are varied and the modelled PSD compared to the PSD measured in the ash cloud during the eruption of Eyjafjallajökull in 2010 by the FAAM research aircraft. The influence of the weather on PSD is also considered by comparing model output using an idealised atmosphere to output using NWP driven meteorological fields. We discuss the sensitivity of forecasts of

  3. Agricultural Fragility Estimates Subjected to Volcanic Ash Fall Hazards

    Science.gov (United States)

    Ham, H. J.; Lee, S.; Choi, S. H.; Yun, W. S.

    2015-12-01

    Agricultural Fragility Estimates Subjected to Volcanic Ash Fall Hazards Hee Jung Ham1, Seung-Hun Choi1, Woo-Seok Yun1, Sungsu Lee2 1Department of Architectural Engineering, Kangwon National University, Korea 2Division of Civil Engineering, Chungbuk National University, Korea ABSTRACT In this study, fragility functions are developed to estimate expected volcanic ash damages of the agricultural sector in Korea. The fragility functions are derived from two approaches: 1) empirical approach based on field observations of impacts to agriculture from the 2006 eruption of Merapi volcano in Indonesia and 2) the FOSM (first-order second-moment) analytical approach based on distribution and thickness of volcanic ash observed from the 1980 eruption of Mt. Saint Helens and agricultural facility specifications in Korea. Fragility function to each agricultural commodity class is presented by a cumulative distribution function of the generalized extreme value distribution. Different functions are developed to estimate production losses from outdoor and greenhouse farming. Seasonal climate influences vulnerability of each agricultural crop and is found to be a crucial component in determining fragility of agricultural commodities to an ash fall. In the study, the seasonality coefficient is established as a multiplier of fragility function to consider the seasonal vulnerability. Yields of the different agricultural commodities are obtained from Korean Statistical Information Service to create a baseline for future agricultural volcanic loss estimation. Numerically simulated examples of scenario ash fall events at Mt. Baekdu volcano are utilized to illustrate the application of the developed fragility functions. Acknowledgements This research was supported by a grant 'Development of Advanced Volcanic Disaster Response System considering Potential Volcanic Risk around Korea' [MPSS-NH-2015-81] from the Natural Hazard Mitigation Research Group, Ministry of Public Safety and Security of

  4. Evolution of volcanic gas composition during repeated culmination of volcanic activity at Kuchinoerabujima volcano, Japan

    Science.gov (United States)

    Shinohara, H.; Hirabayashi, J.; Nogami, K.; Iguchi, M.

    2011-04-01

    Chemical and isotopic compositions of low to medium temperature fumarolic gasses were measured at various fumaroles of Kuchinoerabujima volcano from 1993 to 2009 by the combination of fumarolic gas sampling and Multi-GAS measurement of volcanic plumes. Repeated culmination of the volcanic activity was observed as contemporaneous occurrence of seismic swarms, summit inflation and demagnetization, almost every two years after 1999. Fumarolic activity also increased parallel with these activities; new fumarolic fields of low-temperature fumaroles at boiling point formed at the southern and western rims of the summit crater in 2003 and intense degassing activity started at medium-temperature fumaroles inside the summit crater in 2008. The low-temperature fumarolic gasses have peculiar composition with high H 2/H 2O, CO/CO 2 and SO 2/H 2S ratios, typical features of high-temperature volcanic gasses, but also with low HCl and total S contents, typical features of low-temperature gasses. These features indicate that the gasses are formed by low-temperature differentiation of high-temperature gasses. Variation of H and O isotopic ratios of the low-temperature gasses indicates that the gasses are formed by isoenthalpic processes of vapor-liquid separation at 100 °C of a high-temperature gas and meteoric water mixture, implying that the high-temperature gas was injected into a shallow aquifer without cooling. Temperatures of the high-temperature gasses were estimated as 550-700 °C based on the equilibrium temperature calculation with considering the low-temperature differentiation. The medium-temperature fumarolic gasses from the summit crater have typical compositions of high-temperature volcanic gasses and are estimated as the source gas of the boiling point fumaroles. The H 2/H 2O and CO 2/S t ratios of the low-temperature fumaroles increased from 2004 to 2009, which is interpreted to be caused by the evolution of thermal structure of a shallow gas storage region of a

  5. Characterization of fine volcanic ash from explosive eruption from Sakurajima volcano, South Japan

    Science.gov (United States)

    Nanayama, F.; Furukawa, R.; Ishizuka, Y.; Yamamoto, T.; Geshi, N.; Oishi, M.

    2013-12-01

    Explosive volcanic eruptions can affect infrastructure and ecosystem by their dispersion of the volcanic particle. Characterization of volcanic particle expelled by explosive eruption is crucial for evaluating for quantitative hazard assessment by future volcanic eruption. Especially for fine volcanic ash less than 64 micron in diameter, it can disperse vast area from the source volcano and be easily remobilized by surface wind and precipitation after the deposition. As fine volcanic ash is not preserved well at the earth surface and in strata except for enormously large scale volcanic eruption. In order to quantify quantitative characteristics of fine volcanic ash particle, we sampled volcanic ash directly falling from the eruption cloud from Showa crater, the most active vent of Sakurajima volcano, just before landing on ground. We newly adopted high precision digital microscope and particle grain size analyzer to develop hazard evaluation method of fine volcanic ash particle. Field survey was performed 5 sequential days in January, 2013 to take tamper-proof volcanic ash samples directly obtained from the eruption cloud of the Sakurajima volcano using disposable paper dishes and plastic pails. Samples were taken twice a day with time-stamp in 40 localities from 2.5 km to 43 km distant from the volcano. Japan Meteorological Agency reported 16 explosive eruptions of vulcanian style occurred during our survey and we took 140 samples of volcanic ash. Grain size distribution of volcanic ash was measured by particle grain size analyzer (Mophologi G3S) detecting each grain with parameters of particle diameter (0.3 micron - 1 mm), perimeter, length, area, circularity, convexity, solidity, and intensity. Component of volcanic ash was analyzed by CCD optical microscope (VHX-2000) which can take high resolution optical image with magnifying power of 100-2500. We discriminated each volcanic ash particle by color, texture of surface, and internal structure. Grain size

  6. November 2015 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2015-11-01

    Full Text Available No abstract available. Article truncated after 150 words. The November 2015 Arizona Thoracic Society meeting was held on Wednesday, November 18, 2015 at the Scottsdale Shea Hospital beginning at 6:30 PM. This was a dinner meeting with case presentations. There were 14 in attendance representing the pulmonary, critical care, sleep, and radiology communities. There were 3 case presentations: 1. Dr. Gerald Schwartzberg presented a case of a 56-year-old man with a history of diabetes, alcoholism and tobacco abuse who has a history of Mycobacterium avium-intracellulare (MAI with a residual thin-walled cavity in his right upper lobe (RUL. After quitting drinking and smoking and years of being asymptomatic, he presented with hemoptysis. Chest x-ray showed increasing density in the RUL. CT scan showed an intracavitary density in his previous cavity presumably a fungus ball. Sputum cultures are pending. Discussion followed on management of fungus balls. Bronchoscopy was recommended to view the bronchial anatomy to exclude other diagnosis as well ...

  7. Presymptomatic Parkinson's disease: the Arizona experience.

    Science.gov (United States)

    Caviness, John N

    2012-01-01

    There is a growing interest in presymptomatic diagnosis of Parkinson's disease (PD), but the best and most practical method to screen and confirm asymptomatic individuals for PD needs further study. The Banner-Sun Health Brain and Body Donation program in Sun City, Arizona has studied primarily PD and Alzheimer's disease. Enrollees receive annual prospective standardized evaluation that includes clinical, biomarker testing, and at autopsy, neuropathological examination is performed followed by a consensus conference that determines final diagnosis. Since numerous Controls receive these assessments, these subjects become an excellent cohort to study presymptomatic PD. We found that Controls with partial diagnostic criteria for PD (1 of either rest tremor or bradykinesia) had a 6.6 relative risk for eventually developing full diagnostic criteria for PD. Neuropathologic examination has uncovered cases of "incidental Lewy body disease" (ILBD). We have shown that ILBD cases during life demonstrated no significant differences in clinical assessment versus similarly assessed controls. However, electrophysiological assessment showed subclinical low frequency rest discharges in some ILBD cases. Electroencephalography spectral frequency of ILBD cases was lower than for controls but not as low as for PD cases. The longitudinal assessments of this brain bank offer significant opportunities for the study of presymptomatic PD. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. July 2016 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2016-07-01

    Full Text Available No abstract available. Article truncated after first 150 words. The July 2016 Arizona Thoracic Society meeting was held on Wednesday, July 27, 2016 at the Scottsdale Shea Hospital beginning at 6:30 PM. This was a dinner meeting with case presentations. There were 14 in attendance representing the pulmonary, critical care, sleep, and radiology communities. Prior to the case presentations, a discussion was held on 4 issues. First, Dr. Rick Robbins gave a summary of ATS Hill Day. During Hill Day a presentation was given by a representative from the Campaign for Tobacco-Free Kids. Their web site lists tobacco company contributions to members of Congress on their web site. Dr. Gary Ewart from the ATS office in Washington gave a presentation on the Traditional Cigar Manufacturing and Small Business Jobs Preservation Act before Congress (aka the Cigar Bill which the ATS opposes. He noted that cosponsors for the bill included several Congressmen from Southwestern states. Dr. Robbins combined the two ...

  9. October 2013 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2013-10-01

    Full Text Available No abstract available. Article truncated after 150 words. The October Arizona Thoracic Society meeting was held on Wednesday, 10/23/2013 at Shea Hospital beginning at 6:30 PM. There were 21 in attendance representing the pulmonary, critical care, sleep, and thoracic surgery communities. A proposal was made to decrease the number of meetings from 10 to 8 per year. After a brief discussion, this was adopted. Dr. Parides will try and coordinate these changes with Tucson. Meetings were announced for December in Tucson, January in Carmel, February in Albuquerque, and April in Phoenix. A suggestion was made to have a separate area for meetings on the SWJPCC website. There were 2 cases presented-both by Nick Sparacino, a first year fellow at Good Samaritan/VA. 1. The first case was a 48 year old man admitted to podiatry for chronic diabetic foot ulcers. His preoperative chest x-ray revealed multiple pulmonary nodules. Importantly, he had a history of working in a brake pad …

  10. Geothermal development plan: northern Arizona counties

    Energy Technology Data Exchange (ETDEWEB)

    White, D.H.; Goldstone, L.A.

    1982-08-01

    The Northern Counties Area Development Plan evaluated the regional market potential for utilizing geothermal energy. This study identified five potential geothermal resource areas, four of which have low temperature (<90{sup 0}C, 194{sup 0}F) potential and one possible igneous system. The average population growth rate in the Northern Counties is expected to be five percent per year over the next 40 years, with Mohave and Yavapai Counties growing the fastest. Rapid growth is anticipated in all major employment sectors, including trade, service, manufacturing, mining and utilities. A regional energy use analysis is included, containing information on current energy use patterns for all user classes. Water supplies are expected to be adequate for expected growth generally, though Yavapai and Gila Counties will experience water deficiencies. A preliminary district heating analysis is included for the towns of Alpine and Springerville. Both communities are believed located on geothermal resource sites. The study also contains a section identifying potential geothermal resource users in northern Arizona.

  11. MAZATZAL WILDERNESS AND CONTIGUOUS ROADLESS AREAS, ARIZONA.

    Science.gov (United States)

    Wrucke, Chester T.; Ellis, Clarence E.

    1984-01-01

    A mineral survey has shown that the Mazatzal Wilderness, Arizona has demonstrated resources of silver, gold, lead and mercury, small areas of substantiated mineral-resource potential for silver and copper, and areas of probable resource potential for resources of silver, copper, lead, mercury, and molybdenum. Gold, silver, and copper resources occur in small deposits in the north-central, eastern, and southern parts of the wilderness. A small demonstrated mercury resource is located at the Sunflower mine near the southeastern corner of the wilderness adjacent to the well-known Sunflower mining district. Molybdenum mineralization found during this study in the Tangle Creek area west of the Verde River may extend eastward into the roadless area and the wilderness. Tin occurrences not previously known in the Mazatzal region were found in the central part of the wilderness, and uranium was found near Horseshoe Reservoir, but there is little promise for the occurrence of tin and uranium resources. No potential for fossil fuel resources was identified in this study.

  12. September 2012 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2012-09-01

    Full Text Available No abstract available. Article truncated at 150 words. A dinner meeting was held on 9/26//2012 at Scottsdale Shea beginning at 6:30 PM. There were 18 in attendance representing the pulmonary, critical care, sleep, pathology, and radiology communities.A discussion was held on Pending Premium Cigar Legislation HR. 1639 and S.1461, the "Traditional Cigar Manufacturing and Small Business Jobs Preservation Act of 2011”. This bill would exempt "premium cigars" from FDA oversight. The definition of premium cigars is so broad that candy flavored cigars, cigarillos and blunts would be exempted from FDA regulation. Teenage cigar smoking is increasing and this legislation may result in a further increase. The Arizona Thoracic Society is opposed to this bill. Dr. Robbins is to put a link on the Southwest Journal of Pulmonary and Critical Care website linking to the ATS website. This will enable members to contact their Congressmen opposing this legislation. A discussion was also held on a proposed combined Tucson/Phoenix …

  13. Slides showing aeromagnetic and gravity data for regional mineral exploration in Colorado, New Mexico, and Arizona

    Science.gov (United States)

    Klein, Douglas P.

    1983-01-01

    Examples of aeromagnetic and gravity data over 1? x 2? areas are presented for regions near the Cripple Creek mining area, Colorado, and the Lordsburg-Tyrone-Silver City mining areas, southern New Mexico and Arizona. These data indicate broad crustal structures and compositional variations that are marked by magnetization and density contrasts. The focus is on anomalies that may signal large-dimension controlling structures for the emplacement of economic mineral deposits. An example is a continuous, quasi-linear, north-trending gradient in both gravity and magnetic data located west of Cripple Creek area along long. 105? 30? W. This trend correlates with two mineral deposits of the Southern Rocky Mountains Front Range. It also correlates in part with an area of volcanic rock and with a mapped fault complex (Elkhorn-Currant Creek-Else-Westcliffe). The trend is interpreted to indicate a continuous crustal fault system, although exposures of this system are discontinuous between areas of alluvium and volcanic-rock cover. Similar geophysical trends exist in the Silver City to Tyrone area, where northeast-and northwest-trending anomalies appear to be marked by intrusion and mineralization. In this area, northwest-trending alluvial basins favor the use of geophysics to infer economically accessible but hidden bedrock whose association with exposed mineralization seems possible. An example of an inferred broad and relatively shallow, but hidden bedrock complex in association with more areally-limited mineralization is the Victorio Mountains area about 34 mi (55 km) south-southeast of Tyrone, New Mexico. The mineralization is within faulted sediments whose outcrop covers a small portion of the geophysical anomaly-complex.

  14. Volcanic eruptions; energy and size

    Science.gov (United States)

    de la Cruz-Reyna, S.

    1991-01-01

    The Earth is a dynamic planet. Many different processes are continuously developing, creating a delicate balance between the energy stored and generated in its interior and the heat lost into space. The heat in continuously transferred through complex self-regulating convection mechanisms on a planetary scale. The distribution of terrestrial heat flow reveals some of the fine structure of the energy transport mechanisms in the outer layers of the Earth. Of these mechanisms in the outer layers of the Earth. Of these mechanisms, volcanism is indeed the most remarkable, for it allows energy to be transported in rapid bursts to the surface. In order to maintain the subtle balance of the terrestrial heat machine, one may expect that some law or principle restricts the ways in which these volcanic bursts affect the overall energy transfer of the Earth. For instance, we know that the geothermal flux of the planet amounts to 1028 erg/year. On the other hand, a single large event like the Lava Creek Tuff eruption that formed Yellowstone caldera over half a million years ago may release the same amount of energy in a very small area, over a short period of time. 

  15. Thermal regimes of major volcanic centers: Magnetotelluric constraints

    Energy Technology Data Exchange (ETDEWEB)

    Hermance, J.F.

    1989-10-02

    The interpretation of geophysical/electromagnetic field data has been used to study dynamical processes in the crust beneath three of the major tectono-volcanic features in North America: the Long Valley/Mono Craters Volcanic Complex in eastern California, the Cascades Volcanic Belt in Oregon, and the Rio Grande Rift in the area of Socorro, New Mexico. Primary accomplishments have been in the area of creating and implementing a variety of 2-D generalized inverse computer codes, and the application of these codes to fields studies on the basin structures and he deep thermal regimes of the above areas. In order to more fully explore the space of allowable models (i.e. those inverse solutions that fit the data equally well), several distinctly different approaches to the 2-D inverse problem have been developed: (1) an overdetermined block inversion; (2) an overdetermined spline inverstion; (3) a generalized underdetermined total inverse which allows one to tradeoff certain attributes of their model, such as minimum structure (flat models), roughness (smooth models), or length (small models). Moreover, we are exploring various approaches for evaluating the resolution model parameters for the above algorithms. 33 refs.

  16. Development of mobile sensor for volcanic observation "HOMURA": Test campaigns for a long-term operation

    Science.gov (United States)

    Kaneko, K.; Iwahori, K.; Ito, K.; Sagi, H.

    2016-12-01

    Unmanned robots are useful to observe volcanic phenomena near active volcanic vents, to learn symptoms and transitions of eruptions, and to mitigate volcanic disasters. We have been trying to develop a practical UGV robot for flexible observation of active volcanic vents. We named this system "Homura". In this presentation, we report results of test campaigns of Homura for observation in a volcanic field. We have developed a prototype of Homura, which is a small robot vehicle with six wheels (75 x 43 x 31 cm and a weight of about 12 kg). It is remotely controlled with mobile phone radio waves; it can move in volcanic fields and send real time data of sensors (camera and gas sensors) equipped in the vehicle to the base station. Homura has a small solar panel (4 W). Power consumption of Homura is about 4 W in operation of sensors and less than 0.1 W in idle state, so that Homura can work outdoors for a long time by intermittent operation.We carried out two test campaigns of Homura at Iwo-yama to examine if Homura can work for a few month in natural volcanic fields (however, it had no solar panel in these campaigns). Iwo-yama is one of craters in the Kirishima volcanic field, SW Japan; the area within 1 km from the crater was an off-limit area from Oct., 2014 to May, 2015 and from Feb. to Mar., 2016 because of strong volcanic seismicity. On Feb. 19th, 2015 and Mar. 7th, 2016, we carried and put Homura at the rim of the crater. Unfortunately, mobile phone connectivity was not entirely stable around Iwo-yama. Then, we did not move Homura and only obtain real time data of the sensors. In the two campaigns, we operated Homura at our office for a few hours every day for 49 and 37 days, respectively. Although the weather was often bad (rain, fog, or cold temperature) during the campaigns, Homura perfectly worked. The results of these campaigns indicate that Homura is useful as s simple monitoring station in volcanic fields where mobile phone connection is available.

  17. RiskScape Volcano: Development of a risk assessment tool for volcanic hazards

    Science.gov (United States)

    Deligne, Natalia; King, Andrew; Jolly, Gill; Wilson, Grant; Wilson, Tom; Lindsay, Jan

    2013-04-01

    RiskScape is a multi-hazard risk assessment tool developed by GNS Science and the National Institute of Water and Atmospheric Research Ltd. (NIWA) in New Zealand that models the risk and impact of various natural hazards on a given built environment. RiskScape has a modular structure: the hazard module models hazard exposure (e.g., ash thickness at a given location), the asset module catalogues assets (built environment, infrastructure, and people) and their attributes exposed to the hazard, and the vulnerability module models the consequences of asset exposure to the hazard. Hazards presently included in RiskScape are earthquakes, river floods, tsunamis, windstorms, and ash from volcanic eruptions (specifically from Ruapehu). Here we present our framework for incorporating other volcanic hazards (e.g., pyroclastic density currents, lava flows, lahars, ground deformation) into RiskScape along with our approach for assessing asset vulnerability. We also will discuss the challenges of evaluating risk for 'point source' (e.g., stratovolcanoes) vs 'diffuse' (e.g., volcanic fields) volcanism using Ruapehu and the Auckland volcanic field as examples. Once operational, RiskScape Volcano will be a valuable resource both in New Zealand and internationally as a practical tool for evaluating risk and also as an example for how to predict the consequences of volcanic eruptions on both rural and urban environments.

  18. Soils of volcanic regions in Europe

    NARCIS (Netherlands)

    Arnalds, O.; Bartoli, F.; Buurman, P.; Oskarsson, H.; Stoops, G.; García-Rodeja, E.

    2007-01-01

    Soils of volcanic areas often exhibit unique properties differentiating them from other soils on Earth. This book gives comprehensive coverage of soils in volcanic regions within Europe, dealing with most aspects of modern day soil science. It covers a range of issues such as mineralogy, chemistry,

  19. The use of luminescence for dating young volcanic eruptions

    Science.gov (United States)

    Schmidt, Christoph; Schaarschmidt, Maria; Kolb, Thomas; Richter, Daniel; Tchouankoue, Jean Pierre; Zöller, Ludwig

    2017-04-01

    Reliable chronologies of volcanic eruptions are vital for hazard analysis, but dating of Holocene and Late Pleistocene volcanism poses a major challenge. Established techniques such as 40Ar/39Ar are often problematic due to the long half-life of 40K or the absence of datable materials. In this context, luminescence dating methods are an alternative since they are applicable to Earth's most common minerals and to a range of different datable events. Luminescence signal resetting during volcanic activity can be caused by heat (lava, contact to lava), light (disintegration of ejecta) or (temperature-assisted) pressure in the course of phreatomagmatic explosions. While volcanogenic minerals assembling basalt or other volcanic rocks are less suitable for luminescence dating due to so-called anomalous fading, the signal of volcanogenically heated or fragmented country rock actually relates to the time of eruption as well and further provides reproducible results. This contribution aims to illustrate the potential of this latter approach by presenting two case studies. The first refers to two Late Pleistocene scoria cones in the Westeifel Volcanic Field (WEVF), Germany, of which the Wartgesberg locality was dated by 40Ar/39Ar and 14C, while the closeby Facher Höhe is chronologically poorly constrained (Mertz et al. 2015; pers comm. Luise Eichhorn, 2016). The former locality allows testing the accuracy of various luminescence techniques (thermoluminescence, TL, optically stimulated luminescence, OSL, infrared stimulated luminescence, IRSL) applied to quartz and feldspar against independent age control. The other study site is the monogenetic Lake Nyos Maar as part of the Cameroon Volcanic Line, having killed 1,700 people in 1986 following the release of large amounts of CO2. Previous dating efforts of the last explosive activity are inconsistent and yielded age estimates ranging from 400 a (14C) to >350 ka (K-Ar) (Aka et al. 2008). Our results demonstrate that multiple

  20. Quaternary basaltic volcanism in the Payenia volcanic province, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina

    primitive basalts and trachybasalts but also more evolved samples from the retroarc region and the larger volcanoes Payún Matrú and Payún Liso are presented. The samples cover a broad range of compositions from intraplate lavas similar to ocean island basalts to arc andesites. A common feature found...... are isotopically similar to the Andean Southern Volcanic Zone arc rocks and their mantle source possibly resembled the source of South Atlantic N-MORB prior to addition of fluids and melts from the subduction channel. However, it must have been more enriched than the estimates of depleted upper mantle from...... the lithosphere is thinnest and possibly in areas of elevated mantle temperatures. The pyroxenite melts formed at deeper levels react with the surrounding peridotite and thereby changes composition leading to eruption of melts which experienced variable degrees of melt-peridotite interaction. This can presumably...

  1. Reservoir characteristics and control factors of Carboniferous volcanic gas reservoirs in the Dixi area of Junggar Basin, China

    Directory of Open Access Journals (Sweden)

    Ji'an Shi

    2017-02-01

    Full Text Available Field outcrop observation, drilling core description, thin-section analysis, SEM analysis, and geochemistry, indicate that Dixi area of Carboniferous volcanic rock gas reservoir belongs to the volcanic rock oil reservoir of the authigenic gas reservoir. The source rocks make contact with volcanic rock reservoir directly or by fault, and having the characteristics of near source accumulation. The volcanic rock reservoir rocks mainly consist of acidic rhyolite and dacite, intermediate andesite, basic basalt and volcanic breccia: (1 Acidic rhyolite and dacite reservoirs are developed in the middle-lower part of the structure, have suffered strong denudation effect, and the secondary pores have formed in the weathering and tectonic burial stages, but primary pores are not developed within the early diagenesis stage. Average porosity is only at 8%, and the maximum porosity is at 13.5%, with oil and gas accumulation showing poor performance. (2 Intermediate andesite and basic basalt reservoirs are mainly distributed near the crater, which resembles the size of and suggests a volcanic eruption. Primary pores are formed in the early diagenetic stage, secondary pores developed in weathering and erosion transformation stage, and secondary fractures formed in the tectonic burial stage. The average porosity is at 9.2%, and the maximum porosity is at 21.9%: it is of the high-quality reservoir types in Dixi area. (3 The volcanic breccia reservoir has the same diagenetic features with sedimentary rocks, but also has the same mineral composition with volcanic rock; rigid components can keep the primary porosity without being affected by compaction during the burial process. At the same time, the brittleness of volcanic breccia reservoir makes it easily fracture under the stress; internal fracture was developmental. Volcanic breccia developed in the structural high part and suffered a long-term leaching effect. The original pore-fracture combination also made

  2. Geomorphological Approach for Regional Zoning In The Merapi Volcanic Area

    Directory of Open Access Journals (Sweden)

    Langgeng Wahyu Santosa

    2013-07-01

    Full Text Available Geomorphologial approach can be used as the basic for identifying and analyzing the natural resources potentials, especially in volcanic landscape. Based on its geomorphology, Merapi volcanic landscape can be divided into 5 morphological units, i.e.: volcanic cone, volcanic slope, volcanic foot, volcanic foot plain, and fluvio-volcanic plain. Each of these morphological units has specific characteristic and natural resources potential. Based on the condition of geomorphology, the regional zoning can be compiled to support the land use planning and to maintain the conservation of environmental function in the Merapi Volcanic area.

  3. The Galileoscope project: community-based technology education in Arizona

    Science.gov (United States)

    Pompea, Stephen M.; Fine, Leonard W.; Sparks, Robert T.; Walker, Constance E.; Dugan, Charles L.; Dokter, Erin F. C.

    2014-07-01

    A program model has been developed and implemented over the last three years to provide a robust optical technologybased science education program to students aged 9-11 years (5th grade), a formative time in the development of a student's interest in science and engineering. We have created well-tested and evaluated teaching kits for the classroom to teach about the basics of image formation and telescopes. In addition we provide professional development to the teachers of these students on principles of optics and on using the teaching kits. The program model is to reach every teacher and every student in a number of mid-sized rural communities across the state of Arizona. The Galileoscope telescope kit is a key part of this program to explore optics and the nature of science. The program grew out of Module 3 of the NSF-Supported Hands-On Optics project (SPIE, OSA, and NOAO) and from the Science Foundation Arizona-supported Hands-On Optics Arizona program. NOAO has conducted this program in Flagstaff, Yuma, Globe, and Safford, Arizona and is being expanded to sites across the entire state of Arizona (295,254 square kilometers). We describe the educational goals, evaluations, and logistical issues connected to the program. In particular, we proposed that this model can be adapted for any rural or urban locations in order to encourage interest in science, astronomy and optics.-

  4. Geochemical characteristics of volcanic rocks from selected locations located in Idaho, USA and the Korean Peninsula

    Science.gov (United States)

    Kim, K. J.; Heldmann, J. L.; Lim, D. S. S.; van Gasselt, S.; Sun, C.; Yi, E.; Lee, Y.

    2016-12-01

    We have been investigating the geochemical characteristics of volcanic rocks of selected regions located in Idaho, USA and compared them to the geochemistry of those found on the Korean Peninsula. In particular, we compare volcanic rocks from the Craters of the Moon (COM) and the King's Bowl (KB) volcanic fields to those of Mt. Baekdu and Ulueng Island in order to gather an understanding about the source of magma that is revealed at the current surface of those volcanic fields. Our preliminary investigation confirmed that the geochemical characteristics of volcanic rocks from KB compare well with the geochemical characteristics of returned lunar samples with respect to both low K2O+Na2O and low SiO2 contents exhibiting the geochemical characteristics of a mantle origin. This mantle geochemistry is also clearly observed in both regions of Ulueng Island and Mt. Baekdu. The magma sources of Ulueng Island and Mt. Baekdu are known to be located in a depth of about 30 and 5 10 km, respectively, with initial eruption dates at approximately 1.4 and 28 million years ago, respectively. Volcanic core samples taken at a depth of 4 km at Uleung Island and mantle source rock of Mt. Baekdu reveal geochemical characteristics of lunar basalts confirming even more that both magma source of and evolutionary processes on the Earth's moon closely compare to terrestrial volcanic processes associated with mantle sources. The mantle rock of Mt. Baekdu is a picrite basalt which shows close similarities to lunar basalts. It was also found that volcanic rocks from the COM and Mt. Baekdu show quite similar geochemical evolutionary features while rocks from Uleung Island reveal more alkaline characteristics. This presentation introduces aspects of the relationship between mantle sources and evolutionary features from lunar and terrestrial rocks from selected location.

  5. Volcanism and associated hazards: the Andean perspective

    Science.gov (United States)

    Tilling, R. I.

    2009-12-01

    Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years) than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions") recognized worldwide that have occurred from the Ordovician to the Pleistocene. The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru). The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars) were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent hazardous eruptions in Chile, Colombia, Ecuador, and Peru has spurred significant improvements in reducing volcano risk in the Andean region. But much remains to be done.

  6. Cost-Effectiveness Analysis of the Residential Provisions of the 2015 IECC for Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Mendon, Vrushali V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhao, Mingjie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Taylor, Zachary T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Poehlman, Eric A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-02-15

    The 2015 IECC provides cost-effective savings for residential buildings in Arizona. Moving to the 2015 IECC from the 2009 IECC base code is cost-effective for residential buildings in all climate zones in Arizona.

  7. Public Land Survey (Township, Range, and Section) for northern Arizona, including Grand Canyon National Park.

    Data.gov (United States)

    National Park Service, Department of the Interior — This ALRIS (Arizona Land Resource Information System) coverage contains Public Land Survey gridding and labels for Townships, Ranges, and Sections for Northern Arizona

  8. Arizona Vegetation Resource Inventory (AVRI) accuracy assessment

    Science.gov (United States)

    Szajgin, John; Pettinger, L.R.; Linden, D.S.; Ohlen, D.O.

    1982-01-01

    A quantitative accuracy assessment was performed for the vegetation classification map produced as part of the Arizona Vegetation Resource Inventory (AVRI) project. This project was a cooperative effort between the Bureau of Land Management (BLM) and the Earth Resources Observation Systems (EROS) Data Center. The objective of the accuracy assessment was to estimate (with a precision of ?10 percent at the 90 percent confidence level) the comission error in each of the eight level II hierarchical vegetation cover types. A stratified two-phase (double) cluster sample was used. Phase I consisted of 160 photointerpreted plots representing clusters of Landsat pixels, and phase II consisted of ground data collection at 80 of the phase I cluster sites. Ground data were used to refine the phase I error estimates by means of a linear regression model. The classified image was stratified by assigning each 15-pixel cluster to the stratum corresponding to the dominant cover type within each cluster. This method is known as stratified plurality sampling. Overall error was estimated to be 36 percent with a standard error of 2 percent. Estimated error for individual vegetation classes ranged from a low of 10 percent ?6 percent for evergreen woodland to 81 percent ?7 percent for cropland and pasture. Total cost of the accuracy assessment was $106,950 for the one-million-hectare study area. The combination of the stratified plurality sampling (SPS) method of sample allocation with double sampling provided the desired estimates within the required precision levels. The overall accuracy results confirmed that highly accurate digital classification of vegetation is difficult to perform in semiarid environments, due largely to the sparse vegetation cover. Nevertheless, these techniques show promise for providing more accurate information than is presently available for many BLM-administered lands.

  9. Integrated solid waste management of Scottsdale, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    The subject document reports the results of an in-depth investigation of the fiscal year 1992 cost of the city of Scottsdale, Arizona, integrated municipal solid waste management (IMSWM) system, the energy consumed to operate the system, and the environmental performance requirements for each of the system`s waste-processing and disposal facilities. The document reports actual data from records kept by participants. Every effort was made to minimize the use of assumptions, and no attempt is made to interpret the data reported. Analytical approaches are documented so that interested analysts may per-form manipulation or further analysis of the data. As such, the report is a reference document for municipal solid waste (MSW) management professionals who are interested in the actual costs and energy consumption, for a 1-year period, of an operating IMSWM system. The report is organized into two main parts. The first part is the executive summary and case study portion of the report. The executive summary provides a basic description of the study area and selected economic and energy information. Within the case study are detailed descriptions of each component operating during the study period; the quantities of solid waste collected, processed, and marketed within the study boundaries; the cost of MSW in Scottsdale; an energy usage analysis; a review of federal, state, and local environmental requirement compliance; a reference section; and a glossary of terms. The second part of the report focuses on a more detailed discourse on the above topics. In addition, the methodology used to determine the economic costs and energy consumption of the system components is found in the second portion of this report. The methodology created for this project will be helpful for those professionals who wish to break out the costs of their own integrated systems.

  10. Causes of sinks near Tucson, Arizona, USA

    Science.gov (United States)

    Hoffmann, John P.; Pool, Donald R.; Konieczki, A. D.; Carpenter, Michael C.

    Land subsidence in the form of sinks has occurred on and near farmlands near Tucson, Pima County, Arizona, USA. The sinks occur in alluvial deposits along the flood plain of the Santa Cruz River, and have made farmlands dangerous and unsuitable for farming. More than 1700 sinks are confined to the flood plain of the Santa Cruz River and are grouped along two north-northwestward-trending bands that are approximately parallel to the river and other flood-plain drainages. An estimated 17,000m3 of sediment have been removed in the formation of the sinks. Thirteen trenches were dug to depths of 4-6m to characterize near-surface sediments in sink and nonsink areas. Sediments below about 2m included a large percentage of dispersive clays in sink areas. Sediments in nonsink areas contain a large component of medium- to coarse-grained, moderately to well sorted sand that probably fills a paleochannel. Electromagnetic surveys support the association of silts and clays in sink areas that are highly electrically conductive relative to sand in nonsink areas. Sinks probably are caused by the near-surface process of subsurface erosion of dispersive sediments along pre-existing cracks in predominantly silt and clay sediments. The pre-existing cracks probably result from desiccation or tension that developed during periods of water-table decline and channel incision during the past 100 years or in earlier periods. Résumé Des effondrements en forme d'entonnoir se sont produits sur et près d'exploitations agricoles de Pima (Arizona). Ces entonnoirs apparaissent dans les alluvions le long de la plaine d'inondation de la rivière Santa Cruz ; ils ont rendu ces terrains dangereux et inexploitables pour l'agriculture. Plus de 1700 entonnoirs existent dans la plaine d'inondation de la rivière Santa Cruz et sont groupés en deux bandes orientées nord-nord-ouest, approximativement parallèles à la rivière et aux autres chenaux de la plaine d'inondation. Un volume de sédiments estim

  11. Baseline susceptibilities of B- and Q-biotype Bemisia tabaci to anthranilic diamides in Arizona.

    Science.gov (United States)

    Li, Xianchun; Degain, Benjamin A; Harpold, Virginia S; Marçon, Paula G; Nichols, Robert L; Fournier, Alfred J; Naranjo, Steven E; Palumbo, John C; Ellsworth, Peter C

    2012-01-01

    Development of pyriproxyfen and neonicotinoid resistance in the B-biotype whitefly and recent introduction of the Q biotype have the potential to threaten current whitefly management programs in Arizona. The possibility of integrating the novel anthranilic diamides chlorantraniliprole and cyantraniliprole into the current program to tackle these threats largely depends on whether these compounds have cross-resistance with pyriproxyfen and neonicotinoids in whiteflies. To address this question, the authors bioassayed a susceptible B-biotype strain, a pyriproxyfen-resistant B-biotype strain, four multiply resistant Q-biotype strains and 16 B-biotype field populations from Arizona with a systemic uptake bioassay developed in the present study. The magnitude of variations in LC(50) and LC(99) among the B-biotype populations or the Q-biotype strains was less than fivefold and tenfold, respectively, for both chlorantraniliprole and cyantraniliprole. The Q-biotype strains were relatively more tolerant than the B-biotype populations. No correlations were observed between the LC(50) (or LC(99)) values of the two diamides against the B- and Q-biotype populations tested and their survival rates at a discriminating dose of pyriproxyfen or imidacloprid. These results indicate the absence of cross-resistance between the two anthranilic diamides and the currently used neonicotinoids and pyriproxyfen. Future variation in susceptibility of field populations to chlorantraniliprole and cyantraniliprole could be documented according to the baseline susceptibility range of the populations tested in this study. Copyright © 2011 Society of Chemical Industry.

  12. Solar-driven membrane distillation demonstration in Leupp, Arizona.

    Science.gov (United States)

    Ravisankar, Vishnu Arvind; Seaman, Robert; Mirchandani, Sera; Arnold, Robert G; Ela, Wendell P

    2016-03-01

    The Navajo Nation is the largest and one of the driest Native American reservations in the US. The population in the Navajo Nation is sporadically distributed over a very large area making it extremely ineffective to connect homes to a centralized water supply system. Owing to this population distribution and the multi decadal drought prevailing in the region, over 40% of the 300,000 people living on Navajo Tribal Lands lack access to running potable water. For many people the only alternative is hauling water from filling stations, resulting in economic hardship and limited supply. A solution to this problem is a de-centralized off-grid water source. The University of Arizona and US Bureau of Reclamation's Solar Membrane Distillation (SMD), stand-alone, pilot desalination system on the Navajo Reservation will provide an off-grid source of potable water; the pilot will serve as a proximal water source, ease the financial hardships caused by the drought, and provide a model for low-cost water treatment systems in arid tribal lands. Bench-scale experiments and an earlier field prototype plant showed viable operation of a solar heated, membrane distillation (MD) system, but further optimization is required. The objectives of the Navajo pilot study are to i) demonstrate integration of solar collectors and membrane distillation, ii) optimize operational parameters, iii) demonstrate and monitor technology performance during extended duration operation, and iv) facilitate independent system operation by the Navajo Water Resources Department, including hand-over of a comprehensive operations manual for implementation of subsequent SMD systems. The Navajo SMD system is designed as a perennial installation that includes remote communication of research data and full automation for remote, unmanned operation.

  13. Volcanic unrest and hazard communication in Long Valley Volcanic Region, California

    Science.gov (United States)

    Hill, David P.; Mangan, Margaret T.; McNutt, Stephen R.

    2017-01-01

    emissions. Initial response plans developed by county and state agencies in response to the volcanic unrest began with “The Mono County Volcano Contingency Plan” and “Plan Caldera” by the California Office of Emergency Services in 1982–84. They subsequently became integrated in the regularly updated County Emergency Operation Plan. The alert level system employed by the USGS also evolved from the three-level “Notice-Watch-Warning” system of the early 1980s through a five level color-code to the current “Normal-Advisory-Watch-Warning” ground-based system in conjunction with the international 4-level aviation color-code for volcanic ash hazards. Field trips led by the scientists proved to be a particularly effective means of acquainting local residents and officials with the geologically active environment in which they reside. Relative caldera quiescence from 2000 through 2011 required continued efforts to remind an evolving population that the hazards posed by the 1980–2000 unrest persisted. Renewed uplift of the resurgent dome from 2011 to 2014 was accompanied by an increase in low-level earthquake activity in the caldera and beneath Mammoth Mountain and continues through May 2016. As unrest levels continue to wax and wane, so will the communication challenges.

  14. Active Volcanism on Io as Seen by Galileo SSI

    Science.gov (United States)

    McEwen, A.S.; Keszthelyi, L.; Geissler, P.; Simonelli, D.P.; Carr, M.H.; Johnson, T.V.; Klaasen, K.P.; Breneman, H.H.; Jones, T.J.; Kaufman, J.M.; Magee, K.P.; Senske, D.A.; Belton, M.J.S.; Schubert, G.

    1998-01-01

    Active volcanism on Io has been monitored during the nominal Galileo satellite tour from mid 1996 through late 1997. The Solid State Imaging (SSI) experiment was able to observe many manifestations of this active volcanism, including (1) changes in the color and albedo of the surface, (2) active airborne plumes, and (3) glowing vents seen in eclipse. About 30 large-scale (tens of kilometers) surface changes are obvious from comparison of the SSI images to those acquired by Voyager in 1979. These include new pyroclastic deposits of several colors, bright and dark flows, and caldera-floor materials. There have also been significant surface changes on Io during the Galileo mission itself, such as a new 400-km-diameter dark pyroclastic deposit around Pillan Patera. While these surface changes are impressive, the number of large-scale changes observed in the four months between the Voyager 1 and Voyager 2 flybys in 1979 suggested that over 17 years the cumulative changes would have been much more impressive. There are two reasons why this was not actually the case. First, it appears that the most widespread plume deposits are ephemeral and seem to disappear within a few years. Second, it appears that a large fraction of the volcanic activity is confined to repeated resurfacing of dark calderas and flow fields that cover only a few percent of Io's surface. The plume monitoring has revealed 10 active plumes, comparable to the 9 plumes observed by Voyager. One of these plumes was visible only in the first orbit and three became active in the later orbits. Only the Prometheus plume has been consistently active and easy to detect. Observations of the Pele plume have been particularly intriguing since it was detected only once by SSI, despite repeated attempts, but has been detected several times by the Hubble Space Telescope at 255 nm. Pele's plume is much taller (460 km) than during Voyager 1 (300 km) and much fainter at visible wavelengths. Prometheus-type plumes (50

  15. Evaluating the ecological economic success of riparian restoration projects in Arizona (Abstract)

    Science.gov (United States)

    Gary B. Snider

    2000-01-01

    The past 4 years the Arizona Water Protection Fund provided more than $25 million to individuals and organizations for stream and riparian restoration projects in Arizona. Information which increases the awareness of the value of Arizona's riparian systems is crucial to the incorporation of ecosystem services into decision-making frameworks, which are largely...

  16. Independent Confirmatory Survey Report for the University of Arizona Nuclear Reactor Laboratory, Tucson, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Nick A. Altic

    2011-11-11

    The University of Arizona (University) research reactor is a TRIGA swimming pool type reactor designed by General Atomics and constructed at the University in 1958. The reactor first went into operation in December of 1958 under U.S. Nuclear Regulatory Commission (NRC) license R-52 until final shut down on May 18, 2010. Initial site characterization activities were conducted in February 2009 during ongoing reactor operations to assess the radiological status of the Nuclear Reactor Laboratory (NRL) excluding the reactor tank, associated components, and operating systems. Additional post-shutdown characterization activities were performed to complete characterization activities as well as verify assumptions made in the Decommissioning Plan (DP) that were based on a separate activation analysis (ESI 2009 and WMG 2009). Final status survey (FSS) activities began shortly after the issuance of the FSS plan in May 2011. The contractor completed measurement and sampling activities during the week of August 29, 2011.

  17. Sub-recent volcanism in Northern Patagonia: A tectonomagmatic approach

    Science.gov (United States)

    Massaferro, Gabriela I.; Haller, Miguel J.; D'Orazio, Massimo; Alric, Viviana I.

    2006-07-01

    The Crater Basalt Volcanic Field (CBVF) in northern Patagonia (˜42°S, Chubut province) is located 400 km eastward of the current Peru-Chile Trench and to the southwest of the Meseta de Somuncura, in a back-arc position in the extra-Andean Patagonia. The CBVF lava flows cover glaciation related terraces and present stream valleys. The occurrence of CBVF is related with the Gastre Fault System (GFS), a very significant tectonic feature about 40 km wide. The CBVF volcanics cover a surface of ˜700 km 2, occurring mainly as lava flows and scoria cones. CBVF volcanics have relatively high contents of MgO (6-9 wt.%), Cr (136-289 ppm) and Ni (25-198 ppm), and classify as alkali basalts, basanites and trachybasalts. Geothermometry indicates a crystallization temperature of ˜1140 °C and a ƒO 2 of - 1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event.

  18. Using Volcanic Ash to Remove Dissolved Uranium and Lead

    Science.gov (United States)

    McKay, David S.; Cuero, Raul G.

    2009-01-01

    Experiments have shown that significant fractions of uranium, lead, and possibly other toxic and/or radioactive substances can be removed from an aqueous solution by simply exposing the solution, at ambient temperature, to a treatment medium that includes weathered volcanic ash from Pu'u Nene, which is a cinder cone on the Island of Hawaii. Heretofore, this specific volcanic ash has been used for an entirely different purpose: simulating the spectral properties of Martian soil. The treatment medium can consist of the volcanic ash alone or in combination with chitosan, which is a natural polymer that can be produced from seafood waste or easily extracted from fungi, some bacteria, and some algae. The medium is harmless to plants and animals and, because of the abundance and natural origin of its ingredient( s), is inexpensive. The medium can be used in a variety of ways and settings: it can be incorporated into water-filtration systems; placed in contact or mixed with water-containing solids (e.g., soils and sludges); immersed in bodies of water (e.g., reservoirs, lakes, rivers, or wells); or placed in and around nuclear power plants, mines, and farm fields.

  19. Volcanic caves of East Africa - an overview

    Directory of Open Access Journals (Sweden)

    Jim W. Simons

    1998-01-01

    Full Text Available Numerous Tertiary to recent volcanoes are located in East Africa. Thus, much of the region is made up volcanic rock, which hosts the largest and greatest variety of East Africas caves. Exploration of volcanic caves has preoccupied members of Cave Exploration Group of East Africa (CEGEA for the past 30 years. The various publications edited by CEGEA are in this respect a treasure troves of speleological information. In the present paper an overview on the most important volcanic caves and areas are shortly reported.

  20. 3D View of Grand Canyon, Arizona

    Science.gov (United States)

    2000-01-01

    The Grand Canyon is one of North America's most spectacular geologic features. Carved primarily by the Colorado River over the past six million years, the canyon sports vertical drops of 5,000 feet and spans a 445-kilometer-long stretch of Arizona desert. The strata along the steep walls of the canyon form a record of geologic time from the Paleozoic Era (250 million years ago) to the Precambrian (1.7 billion years ago).The above view was acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument aboard the Terra spacecraft. Visible and near infrared data were combined to form an image that simulates the natural colors of water and vegetation. Rock colors, however, are not accurate. The image data were combined with elevation data to produce this perspective view, with no vertical exaggeration, looking from above the South Rim up Bright Angel Canyon towards the North Rim. The light lines on the plateau at lower right are the roads around the Canyon View Information Plaza. The Bright Angel Trail, which reaches the Colorado in 11.3 kilometers, can be seen dropping into the canyon over Plateau Point at bottom center. The blue and black areas on the North Rim indicate a forest fire that was smoldering as the data were acquired on May 12, 2000.Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as

  1. Ibuprofen adsorption in four agricultural volcanic soils.

    Science.gov (United States)

    Estevez, Esmeralda; Hernandez-Moreno, Jose Manuel; Fernandez-Vera, Juan Ramon; Palacios-Diaz, Maria Pino

    2014-01-15

    Ibuprofen (IB) is a high environmental risk drug and one of the most frequently prescribed in human medicine. Recently, IB has been detected in Gran Canaria in reclaimed water for irrigation and in groundwater. Adsorption was studied in four volcanic soils from three islands of the Canarian Archipelago. Once the biodegradation process has been excluded from the experimental conditions, a batch method was applied using initial concentrations of 1-5-10-20-50-100-200 mg L(-1) and two soil/water ratios (w/V): 1:5 (OECD, 2000) and 1:1. Non-linear and linearized Langmuir and Freundlich equations were well fitted. The wide IB range tested in our batch studies allowed us to measure experimental adsorption values close to the maximum adsorption capacity (S(max)) as estimated by Langmuir, making it possible thereby to validate the use of the Langmuir equation when there is a burst of contamination at high concentration. The distribution coefficient (Kd), S(max) and Retardation Factor (RF) varied from 0.04 to 0.5 kg L(-1), 4-200 mgk g(-1) and 1.2-1.9, respectively. The lowest S(max) and Kd values were found for the 1:1S/W ratio whereas most batch studies employ 1:5S/W ratios, thus obtaining higher adsorption parameters than when considering field conditions (1:1). Despite the high anion retention of andic soils, similar Kd and RF to those reported for other soils were obtained in 1:5, while high S(max) was found. Our results demonstrate that IB adsorption in volcanic areas responds not only to the soil properties commonly cited in adsorption studies, but also depends on andic properties, sorbent concentration and Dissolved Organic Carbon, the higher values of which are related to the lower Kd and S(max). The low RF and low detection frequency of the IB in groundwater suggests that a) reclaimed water irrigation is not the main source of IB, and b) the existence of some uncontrolled water disposal points in the zone. © 2013.

  2. The HISTMAG database: combining historical, archaeomagnetic and volcanic data

    Science.gov (United States)

    Arneitz, Patrick; Leonhardt, Roman; Schnepp, Elisabeth; Heilig, Balázs; Mayrhofer, Franziska; Kovacs, Peter; Hejda, Pavel; Valach, Fridrich; Vadasz, Gergely; Hammerl, Christa; Egli, Ramon; Fabian, Karl; Kompein, Niko

    2017-09-01

    Records of the past geomagnetic field can be divided into two main categories. These are instrumental historical observations on the one hand, and field estimates based on the magnetization acquired by rocks, sediments and archaeological artefacts on the other hand. In this paper, a new database combining historical, archaeomagnetic and volcanic records is presented. HISTMAG is a relational database, implemented in MySQL, and can be accessed via a web-based interface (http://www.conrad-observatory.at/zamg/index.php/data-en/histmag-database). It combines available global historical data compilations covering the last ∼500 yr as well as archaeomagnetic and volcanic data collections from the last 50 000 yr. Furthermore, new historical and archaeomagnetic records, mainly from central Europe, have been acquired. In total, 190 427 records are currently available in the HISTMAG database, whereby the majority is related to historical declination measurements (155 525). The original database structure was complemented by new fields, which allow for a detailed description of the different data types. A user-comment function provides the possibility for a scientific discussion about individual records. Therefore, HISTMAG database supports thorough reliability and uncertainty assessments of the widely different data sets, which are an essential basis for geomagnetic field reconstructions. A database analysis revealed systematic offset for declination records derived from compass roses on historical geographical maps through comparison with other historical records, while maps created for mining activities represent a reliable source.

  3. Resident perception of volcanic hazards and evacuation procedures

    Science.gov (United States)

    Bird, D. K.; Gisladottir, G.; Dominey-Howes, D.

    2009-02-01

    Katla volcano, located beneath the Mýrdalsjökull ice cap in southern Iceland, is capable of producing catastrophic jökulhlaup. The Icelandic Civil Protection (ICP), in conjunction with scientists, local police and emergency managers, developed mitigation strategies for possible jökulhlaup produced during future Katla eruptions. These strategies were tested during a full-scale evacuation exercise in March 2006. A positive public response during a volcanic crisis not only depends upon the public's knowledge of the evacuation plan but also their knowledge and perception of the possible hazards. To improve the effectiveness of residents' compliance with warning and evacuation messages it is important that emergency management officials understand how the public interpret their situation in relation to volcanic hazards and their potential response during a crisis and apply this information to the ongoing development of risk mitigation strategies. We adopted a mixed methods approach in order to gain a broad understanding of residents' knowledge and perception of the Katla volcano in general, jökulhlaup hazards specifically and the regional emergency evacuation plan. This entailed field observations during the major evacuation exercise, interviews with key emergency management officials and questionnaire survey interviews with local residents. Our survey shows that despite living within the hazard zone, many residents do not perceive that their homes could be affected by a jökulhlaup, and many participants who perceive that their homes are safe, stated that they would not evacuate if an evacuation warning was issued. Alarmingly, most participants did not receive an evacuation message during the exercise. However, the majority of participants who took part in the exercise were positive about its implementation. This assessment of resident knowledge and perception of volcanic hazards and the evacuation plan is the first of its kind in this region. Our data can be used

  4. Arsenic in volcanic geothermal fluids of Latin America.

    Science.gov (United States)

    López, Dina L; Bundschuh, Jochen; Birkle, Peter; Armienta, Maria Aurora; Cumbal, Luis; Sracek, Ondra; Cornejo, Lorena; Ormachea, Mauricio

    2012-07-01

    Numerous volcanoes, hot springs, fumaroles, and geothermal wells occur in the Pacific region of Latin America. These systems are characterized by high As concentrations and other typical geothermal elements such as Li and B. This paper presents a review of the available data on As concentrations in geothermal systems and their surficial discharges and As data on volcanic gases of Latin America. Data for geothermal systems in Mexico, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Ecuador, Bolivia, and Chile are presented. Two sources of As can be recognized in the investigated sites: Arsenic partitioned into volcanic gases and emitted in plumes and fumaroles, and arsenic in rocks of volcanic edifices that are leached by groundwaters enriched in volcanic gases. Water containing the most elevated concentrations of As are mature Na-Cl fluids with relatively low sulfate content and As concentrations reaching up to 73.6 mg L⁻¹ (Los Humeros geothermal field in Mexico), but more commonly ranging from a few mg L⁻¹ to tens of mg L⁻¹. Fluids derived from Na-Cl enriched waters formed through evaporation and condensation at shallower depths have As levels of only a few μg L⁻¹. Mixing of Na-Cl waters with shallower meteoric waters results in low to intermediate As concentrations (up to a few mg L⁻¹). After the waters are discharged at the ground surface, As(III) oxidizes to As(V) and attenuation of As concentration can occur due to sorption and co-precipitation processes with iron minerals and organic matter present in sediments. Understanding the mechanisms of As enrichment in geothermal waters and their fate upon mixing with shallower groundwater and surface waters is important for the protection of water resources in Latin America. Copyright © 2011. Published by Elsevier B.V.

  5. The Early Mesozoic volcanic arc of western North America in northeastern Mexico

    Science.gov (United States)

    Barboza-Gudiño, José Rafael; Orozco-Esquivel, María Teresa; Gómez-Anguiano, Martín; Zavala-Monsiváis, Aurora

    2008-02-01

    Volcanic successions underlying clastic and carbonate marine rocks of the Oxfordian-Kimmeridgian Zuloaga Group in northeastern Mexico have been attributed to magmatic arcs of Permo-Triassic and Early Jurassic ages. This work provides stratigraphic, petrographic geochronological, and geochemical data to characterize pre-Oxfordian volcanic rocks outcropping in seven localities in northeastern Mexico. Field observations show that the volcanic units overlie Paleozoic metamorphic rocks (Granjeno schist) or Triassic marine strata (Zacatecas Formation) and intrude Triassic redbeds or are partly interbedded with Lower Jurassic redbeds (Huizachal Group). The volcanic rocks include rhyolitic and rhyodacitic domes and dikes, basaltic to andesitic lava flows and breccias, and andesitic to rhyolitic pyroclastic rocks, including breccias, lapilli, and ashflow tuffs that range from welded to unwelded. Lower-Middle Jurassic ages (U/Pb in zircon) have been reported from only two studied localities (Huizachal Valley, Sierra de Catorce), and other reported ages (Ar/Ar and K-Ar in whole-rock or feldspar) are often reset. This work reports a new U/Pb age in zircon that confirms a Lower Jurassic (193 Ma) age for volcanic rocks exposed in the Aramberri area. The major and trace element contents of samples from the seven localities are typical of calc-alkaline, subduction-related rocks. The new geochronological and geochemical data, coupled with the lithological features and stratigraphic positions, indicate volcanic rocks are part of a continental arc, similar to that represented by the Lower-Middle Jurassic Nazas Formation of Durango and northern Zacatecas. On that basis, the studied volcanic sequences are assigned to the Early Jurassic volcanic arc of western North America.

  6. Climate Variation at Flagstaff, Arizona - 1950 to 2007

    Science.gov (United States)

    Hereford, Richard

    2007-01-01

    INTRODUCTION Much scientific research demonstrates the existence of recent climate variation, particularly global warming. Climate prediction models forecast that climate will change; it will become warmer, droughts will increase in number and severity, and extreme climate events will recur often?desiccating aridity, extremely wet, unusually warm, or even frigid at times. However, the global models apply to average conditions in large grids approximately 150 miles on an edge (Thorpe, 2005), and how or whether specific areas within a grid are affected is unclear. Flagstaff's climate is mentioned in the context of global change, but information is lacking on the amount and trend of changes in precipitation, snowfall, and temperature. The purpose of this report is to understand what may be happening to Flagstaff's climate by reviewing local climate history. Flagstaff is in north-central Arizona south of San Francisco Mountain, which reaches 12,633 feet, the highest in Arizona (fig. 1). At 6,900 feet, surrounded by ponderosa pine forest, Flagstaff enjoys a four-season climate; winter-daytime temperatures are cool, averaging 45 degrees (Fahrenheit). Summer-daytime temperatures are comfortable, averaging 80 degrees, which is pleasant compared with nearby low-elevation deserts. Flagstaff?s precipitation averages 22-inches per year with a range of 9 to 39 inches. Snowfall occurs each season, averaging 97 inches annually. This report, written for the non-technical reader, interprets climate variation at Flagstaff as observed at the National Weather Service (NWS) station at Pulliam Field (or Airport), a first-order weather station staffed by meteorologists (Staudenmaier and others, 2007). The station is on a flat-topped ridge surrounded by forest 5-miles south of Flagstaff at an elevation of 7,003 feet. Data used in this analysis are daily measurements of precipitation (including snowfall) and temperature (maximum and minimum) covering the period from 1950, when the station

  7. Intraplate volcanism influenced by distal subduction tectonics at Jeju Island, Republic of Korea

    Science.gov (United States)

    Brenna, Marco; Cronin, Shane J.; Kereszturi, Gábor; Sohn, Young Kwan; Smith, Ian E. M.; Wijbrans, Jan

    2015-01-01

    The drivers behind the inception of, and the variable, pulsatory eruption rates at distributed intraplate volcanic fields are not well understood. Such broad areas of monogenetic volcanism cover vast areas of the world and are often heavily populated. Reliable models to unravel their behaviour require robust spatio-temporal frameworks within the fields, but an analysis of the potential proximal and distal regional volcano-tectonic processes is also needed. Jeju Island (Republic of Korea) is a volcanic field that has been extensively drilled and dated. It is also located near one of the world's best-studied tectonic plate boundaries: the subduction zone in southwestern Japan, which generates the Ryukyu and SW Japan arcs. A new set of 40Ar/39Ar ages collected from cores penetrating the entire Jeju eruptive pile, along with geochemical information, is used to construct a temporal and volumetric model for the volcano's growth. The overall pattern indicates inception of volcanism at ~1.7 Ma, with an initial 1.2 Myr of low-rate activity, followed by over an order of magnitude rise over the last 0.5 Myr. The magma flux at Jeju correlates well with increased extension rates in the arc/backarc region. In particular, we infer that the increased trenchward mantle flow, caused by the greater rollback of the Philippine Sea Plate, activated pre-existing shear weaknesses in the mantle beneath Jeju, resulting in mantle upwelling and decompression melting that caused a change in compositions and an increase in eruption rates at Jeju. Thus, the volcanic activity of an intraplate field system can be modulated by regional subduction processes occurring more than 650 km away. This model may explain the frequent observation of pulsatory behaviour seen in many monogenetic volcanic fields worldwide that lie within 1,000 km of subduction zones.

  8. Active Volcanic Plumes on Io

    Science.gov (United States)

    1997-01-01

    This color image, acquired during Galileo's ninth orbit around Jupiter, shows two volcanic plumes on Io. One plume was captured on the bright limb or edge of the moon (see inset at upper right), erupting over a caldera (volcanic depression) named Pillan Patera after a South American god of thunder, fire and volcanoes. The plume seen by Galileo is 140 kilometers (86 miles) high and was also detected by the Hubble Space Telescope. The Galileo spacecraft will pass almost directly over Pillan Patera in 1999 at a range of only 600 kilometers (373 miles).The second plume, seen near the terminator (boundary between day and night), is called Prometheus after the Greek fire god (see inset at lower right). The shadow of the 75-kilometer (45- mile) high airborne plume can be seen extending to the right of the eruption vent. The vent is near the center of the bright and dark rings. Plumes on Io have a blue color, so the plume shadow is reddish. The Prometheus plume can be seen in every Galileo image with the appropriate geometry, as well as every such Voyager image acquired in 1979. It is possible that this plume has been continuously active for more than 18 years. In contrast, a plume has never been seen at Pillan Patera prior to the recent Galileo and Hubble Space Telescope images.North is toward the top of the picture. The resolution is about 6 kilometers (3.7 miles) per picture element. This composite uses images taken with the green, violet and near infrared filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. The images were obtained on June 28, 1997, at a range of more than 600,000 kilometers (372,000 miles).The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http

  9. Volcanic Ash Advisory Database, 1983-2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Volcanic ash is a significant hazard to aviation and can also affect global climate patterns. To ensure safe navigation and monitor possible climatic impact, the...

  10. Palaeoclimate: Volcanism caused ancient global warming

    Science.gov (United States)

    Meissner, Katrin J.; Bralower, Timothy J.

    2017-08-01

    A study confirms that volcanism set off one of Earth's fastest global-warming events. But the release of greenhouse gases was slow enough for negative feedbacks to mitigate impacts such as ocean acidification. See Letter p.573

  11. Submarine silicic volcanism: Processes and products

    Digital Repository Service at National Institute of Oceanography (India)

    Kalangutkar, N.G.; Iyer, S.D.

    The occurrence of submarine silicic volcanics is rare at the mid-oceanic ridges, abyssal depths, seamounts and fracture zones. Hydrothermal processes are active in submarine silicic environments and are associated with host ores of Cu, Au, Ag, Pb...

  12. Hazardous present emergency plans for volcanic eruptions in Neapolitan area: evidences from volcanic and magmatological history and modeling.

    Science.gov (United States)

    Mastrolorenzo, Giuseppe; Pappalardo, Lucia

    2010-05-01

    New evidences from volcanic and magmatological features, archaelogical findings, and modeling provide key constraints on the mechanisms and the effects of the explosive eruptions of Somma-Vesuvius and Campi Flegrei, from the prehistory to the modern times. For both volcanic areas, the probability of plinian events (VEI 5) with their complete range of variability is not negligible, differentiated highly explosive magmas are likely already available at depth, and the associated effects of the possible eruption may affect the whole heavily urbanized metropolitan area. Particularly, results of our numerical simulations consistently with field evidences indicate that tephra accumulation during fallout phase of eruption may preserve critical load for roof collapse up to a distance even exceeding 30 km from the vent, while physical proprieties of PDCs may exceed the threshold for human survival even at distance from the vent in the order of 20 km. These results indicate that the appropriate action for the mitigation of volcanic risk should be the complete evacuation of the whole potentially affected area. In contrast with the single intermediate event (1631 sub-plinian eruption) adopted as reference scenario in the present emergency plan for Vesuvius (at present an emergency plan is not available for Campi Flegrei), the adequate reference scenario should correspond to the worst case (VEI 5, for both volcanoes) that not simply reflects the worst eruption occurred in the past but the entire range of the possible events for that VEI. The adoption, during a volcanic crisis, of any minor scenario that accepts variable levels of risk for the people leaving around the volcano, even with the justification of the cost/benefit approach, always may introduce a false perception of safety that may increase the risk.

  13. Volcanic rock properties control sector collapse events

    Science.gov (United States)

    Hughes, Amy; Kendrick, Jackie; Lavallée, Yan; Hornby, Adrian; Di Toro, Giulio

    2017-04-01

    Volcanoes constructed by superimposed layers of varying volcanic materials are inherently unstable structures. The heterogeneity of weak and strong layers consisting of ash, tephra and lavas, each with varying coherencies, porosities, crystallinities, glass content and ultimately, strength, can promote volcanic flank and sector collapses. These volcanoes often exist in areas with complex regional tectonics adding to instability caused by heterogeneity, flank overburden, magma movement and emplacement in addition to hydrothermal alteration and anomalous geothermal gradients. Recent studies conducted on the faulting properties of volcanic rocks at variable slip rates show the rate-weakening dependence of the friction coefficients (up to 90% reduction)[1], caused by a wide range of factors such as the generation of gouge and frictional melt lubrication [2]. Experimental data from experiments conducted on volcanic products suggests that frictional melt occurs at slip rates similar to those of plug flow in volcanic conduits [1] and the bases of mass material movements such as debris avalanches from volcanic flanks [3]. In volcanic rock, the generation of frictional heat may prompt the remobilisation of interstitial glass below melting temperatures due to passing of the glass transition temperature at ˜650-750 ˚C [4]. In addition, the crushing of pores in high porosity samples can lead to increased comminution and strain localisation along slip surfaces. Here we present the results of friction tests on both high density, glass rich samples from Santaguito (Guatemala) and synthetic glass samples with varying porosities (0-25%) to better understand frictional properties underlying volcanic collapse events. 1. Kendrick, J.E., et al., Extreme frictional processes in the volcanic conduit of Mount St. Helens (USA) during the 2004-2008 eruption. J. Structural Geology, 2012. 2. Di Toro, G., et al., Fault lubrication during earthquakes. Nature, 2011. 471(7339): p. 494-498. 3

  14. Volcanism and associated hazards: the Andean perspective

    Directory of Open Access Journals (Sweden)

    R. I. Tilling

    2009-12-01

    Full Text Available Andean volcanism occurs within the Andean Volcanic Arc (AVA, which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions" recognized worldwide that have occurred from the Ordovician to the Pleistocene.

    The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru. The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (<0.05 km3 in 1985 of Nevado del Ruiz (Colombia killed about 25 000 people – the worst volcanic disaster in the Andean region as well as the second worst in the world in the 20th century. The Ruiz tragedy has been attributed largely to ineffective communications of hazards information and indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent

  15. Arizona State's Origins Project Starts with a Big Bang

    Science.gov (United States)

    Mangan, Katherine

    2009-01-01

    For 12 hours at Arizona State University, a sold-out crowd of 3,000 people gave a group of famous scientists a pop-star welcome, cheering their remarks and lining up for autographs after a day full of discussion about black holes, string theory, and evolutionary biology. At a time when program cuts and faculty layoffs dominate the headlines of…

  16. Language Ideologies of Arizona Voters, Language Managers, and Teachers

    Science.gov (United States)

    Fitzsimmons-Doolan, Shannon

    2014-01-01

    Arizona is the site of many explicit language policies as well as ongoing scholarly discussions of related language ideologies--beliefs about the role of language in society. This study adds a critical piece to the investigation of the role of ideologies in language policy processes by thoroughly documenting language ideologies expressed by a…

  17. Defoliation effects on resource allocation in Arizona cottontop ...

    African Journals Online (AJOL)

    Stems plus sheaths from which leaf blades have been removed may be important to Lehmann lovegrass because this tissue is photosynthetically active and contains nitrogen and phosphorus reserves. After defoliation, Arizona cottontop re-established a canopy more quickly than Lehmann lovegrass but differences were ...

  18. Food habits of Bald Eagles breeding in the Arizona desert

    Science.gov (United States)

    Teryl G. Grubb

    1995-01-01

    Of 1814 foraging attempts, prey captures, or nest deliveries by Bald Eagles (Haliaeetus leucocephalus) in 14 Arizona breeding areas during 1983-1985, 1471 observations were identifiable to at least class: fish (76%), mammal (18%), bird (4%), and reptile/amphibian (2%). Forty-five species were recorded: catfish (Ictalurus punctatus, Pylodictis olivaris), suckers (...

  19. Food habits of bald eagles wintering in northern Arizona

    Science.gov (United States)

    Teryl G. Grubb; Roy G. Lopez

    2000-01-01

    We used pellets collected from roosts to supplement incidental foraging observations to identify prey species of Bald Eagles (Haliaeetus leucoughalus) and to evaluate spatial and temporal trends in their food habits while wintering in northern Arizona between 1994-96. We analyzed 1057 pellets collected from 14 roosts, and identified five mammal and...

  20. Timing of hummingbird migration in southeastern Arizona: implications for conservation

    Science.gov (United States)

    Susan M. Wethington; Stephen M. Russell; George C. West

    2005-01-01

    We examined the distribution and abundance of hummingbirds at three study sites in southeastern Arizona, where over 8,000 individuals of twelve species were banded. Banding occurred at two sites in the early 1990s and is currently active at the third. Anna’s (Calype anna), Black-chinned (Archilochus alexandri), and...

  1. Lowland riparian herpetofaunas: the San Pedro River in southeastern Arizona

    Science.gov (United States)

    Philip C. Rosen

    2005-01-01

    Previous work has shown that southeastern Arizona has a characteristic, high diversity lowland riparian herpetofauna with 62-68 or more species along major stream corridors, and 46-54 species in shorter reaches within single biomes, based on intensive fieldwork and museum record surveys. The San Pedro River supports this characteristic herpetofauna, at least some of...

  2. 75 FR 3694 - Radio Broadcasting Services, Peach Springs, Arizona

    Science.gov (United States)

    2010-01-22

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services, Peach Springs, Arizona AGENCY: Federal Communications... procedures for comments, see 47 CFR 1.4125 and 1.420. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. For the reasons discussed in the preamble, the Federal Communications Commission proposes to...

  3. Implementing Structured English Immersion in Arizona: Benefits, Challenges, and Opportunities

    Science.gov (United States)

    Rios-Aguilar, Cecilia; Gonzalez Canche, Manuel S.; Moll, Luis C.

    2012-01-01

    Background/Context: Arizona's most recent English Language Learner (ELL) legislation, starting in the school year 2008-2009, requires all such students be educated through a specific Structured English Immersion (SEI) model: the 4-hour English Language Development (ELD) block. The basic premise behind this particular model is that ELL students…

  4. 75 FR 7518 - State of Arizona Resource Advisory Council Meeting

    Science.gov (United States)

    2010-02-19

    ... Green Valley, Arizona. The FS is proposing to make this property available to the public as an overnight rental for $150 per night. The Kent Springs Cabin with its six rooms can accommodate up to eight people... will be available for overnight use with a maximum capacity of six people. Management of the cabin may...

  5. The Rugged Frontier: A Decade of Charter Schooling in Arizona

    Science.gov (United States)

    Hassel, Bryan C.; Terrell, Michelle Godard

    2004-01-01

    Arizona's charter experience over the past decade has clearly shown the power of a relatively open chartering system. Schools have sprung up in all corners of the state; parents and teachers have flocked to them in great numbers. Interesting new approaches have emerged. Quite a few of the schools have been strikingly successful. In many places,…

  6. 78 FR 25861 - Radio Broadcasting Services; Peach Springs, Arizona

    Science.gov (United States)

    2013-05-03

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Peach Springs, Arizona AGENCY: Federal Communications....S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal...--RADIO BROADCAST SERVICES 0 1. The authority citation for Part 73 continues to read as follows: Authority...

  7. 78 FR 26739 - Radio Broadcasting Services; Ehrenberg, Arizona

    Science.gov (United States)

    2013-05-08

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Ehrenberg, Arizona AGENCY: Federal Communications... Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez... filed by S and H Broadcasting, LLC, proposing the substitution of Channel 228C2 for vacant Channel 286C2...

  8. Language Policy and Bilingual Education in Arizona and Washington State

    Science.gov (United States)

    Johnson, Eric J.; Johnson, David Cassels

    2015-01-01

    In this paper, we compare the bilingual/language education policies of Arizona and Washington to show that state-level language policy plays a critical role in shaping the appropriation of federal language policy [No Child Left Behind Act (NCLB), Title III] and how different state-level language policies impact the district level of policy…

  9. Accelerating the College and Career Readiness of Arizona's Students

    Science.gov (United States)

    Alliance for Excellent Education, 2011

    2011-01-01

    Arizona is in the process of transitioning to new English language arts and mathematics standards that will better prepare students to be successful in college and their careers. Time, effort, and resources must be dedicated to effective implementation in order to realize the promise of these new common core state standards. This paper captures…

  10. Habitat associations of birds and herpetofauna in southeastern Arizona

    Science.gov (United States)

    William M. Block; Kieth E. Severson

    1992-01-01

    The mountains of southeastern Arizona support a large diversity of vegetative plant communities ranging from grassland and desert scrub to spruce-fir forests. These vegetation types provide appropriate conditions for a number of species of vertebrates. Although vertebrates have been the subject of numerous studies in this region, most studies were restricted to one...

  11. Comparison studies of ozone precursors in Phoenix, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, C.; Guyton, J.; Lee, C.P. [Arizona Dept. of Environmental Quality, Phoenix, AZ (United States); Parmar, S. [Atmospheric Analysis and Consulting Co., Ventura, CA (United States)

    1994-12-31

    This paper will present the comparison of the ozone precursors monitoring program for Phoenix, Arizona during 1992 and 1993. Specific details and methodologies will be presented involving collection of air samples and analysis of speciated measurements for reactive VOC and carbonyl precursors responsible for ozone formation. Quality control and quality assurance techniques will also be discussed.

  12. Aspen fencing in northern Arizona: A 15-year perspective

    Science.gov (United States)

    James M. Rolf

    2001-01-01

    Aspen clearcuts in the 1960s and 1970s on the Peaks Ranger District of the Coconino National Forest in northern Arizona failed to regenerate successfully because of browsing primarily by elk. Since 1985, over 400 acres have been successfully regenerated using fencing of various designs to exclude elk. The expense and visual impact of establishing and maintaining over...

  13. A Study of Arizona's Teachers of English Language Learners

    Science.gov (United States)

    Rios-Aguilar, Cecilia; Gonzalez-Canche, Manuel; Moll, Luis C.

    2010-01-01

    In this study a representative sample of 880 elementary and secondary teachers currently teaching in 33 schools across the state of Arizona were asked about their perceptions of how their ELL students were faring under current instructional policies for ELL students. Teachers were surveyed during the Spring of 2010. Overall findings show that most…

  14. Western yellow pine in Arizona and New Mexico

    Science.gov (United States)

    Theodore S. Woolsey

    1911-01-01

    Western yellow pine is to the Southwest what white pine is to the Northeast, or longleaf pine to the Southeast. The commercial forests of Arizona and New Mexico are three-fourths western yellow pine, which furnishes by far the greater part of the lumber used locally as well as that shipped to outside markets. To describe the characteristics of the species and to...

  15. 75 FR 51840 - State of Arizona Resource Advisory Council Meeting

    Science.gov (United States)

    2010-08-23

    ...; Presentation on water processes, issues and strategies affecting public lands in Arizona; State Director Update... Strategy and RAC discussion and recommendations on factors BLM should consider as these strategies are... public who wish to address the Council on BLM programs and business. Under the Federal Lands Recreation...

  16. Prevalence of Mycoplasma ovipneumoniae in desert bighorn sheep in Arizona

    Science.gov (United States)

    Justice-Allen, Anne E.; Luedtke, Clint J.; Overstreet, Matthew; Cain, James W.; Stephenson, Thomas R.

    2011-01-01

    To assess the potential for an epizootic of pneumonia to result from either natural immigration or translocation, we compared the seroprevalence to Mycoplasma ovipneumoniae in several populations of desert bighorn sheep in Arizona. We collected blood samples and nasal or oropharyngeal swabs from 124 desert bighorn sheep (Ovis canadensis nelsoni) from 6 populations in Arizona in 2009 and 2010. M. ovipneumoniae organisms were detected by PCR in 22%, whereas antibodies to M. ovipneumoniae were detected in 47% of tested bighorn sheep. Mycoplasma antibodies were not found in 2 of 6 populations, indicating some bighorn sheep populations in Arizona are naïve to this bacterium. In contrast, others had seroprevalence rates up to 80%. We were able to compare seroprevalence rates and titers over time in 9 individuals (7 individuals included in the 124 bighorn sheep sampled in 2009 and 2010, and 2 individuals originally captured in 2006). Antibody titers persisted for 12 months in individuals from the Kofa National Wildlife Refuge (n = 7) while antibody titers appeared to decline in the Kanab Creek population (n = 2). M. ovipneumoniae is present or has been present in several, but not all, populations of bighorn sheep in Arizona. The results demonstrate the importance of routine health testing for future translocation efforts to reduce disease risk for naive populations.

  17. Arizona Commission of Indian Affairs 1979-1980 Annual Report.

    Science.gov (United States)

    Arizona Commission of Indian Affairs, Phoenix.

    Designed to provide insight into the proceedings, transactions, and findings of the Arizona Commission of Indian Affairs, this 1979-80 annual report reflects the Commission's efforts to act in a liaison capacity between tribes and state government and to provide tribes with technical assistance. The report describes 17 projects completed during…

  18. Arizona Commission of Indian Affairs 1975-76 Annual Report.

    Science.gov (United States)

    Arizona Commission of Indian Affairs, Phoenix.

    The Arizona Commission of Indian Affairs' annual report is issued to inform the Governor, State Legislature, and tribal governments of the proceedings, transactions, findings, and recommendations made by the Commission, and this 1975-76 report presents the following: (1) Commission membership; (2) a map of the American Indian reservation areas in…

  19. Arizona Commission of Indian Affairs 1982 Annual Report.

    Science.gov (United States)

    Arizona Commission of Indian Affairs, Phoenix.

    Designed to provide insight into the proceedings, transactions, and findings of the Arizona Commission of Indian Affairs, this 1981-82 annual report reflects the Commission's efforts to improve communications, understanding and working relationships between tribes and state government to provide tribes with technical assistance. The report…

  20. Arizona Commission of Indian Affairs 1976-1977 Annual Report.

    Science.gov (United States)

    Arizona Commission of Indian Affairs, Phoenix.

    Issued to inform the Governor, State Legislature, and tribal governments of the proceedings, transactions, findings, and recommendations made by the Commission, this 1976-77 annual report includes the following: the Commission's membership; population and acreage of Arizona reservations; commission meetings during the year; projects completed;…

  1. Arizona Commission of Indian Affairs 1981 Annual Report.

    Science.gov (United States)

    Arizona Commission of Indian Affairs, Phoenix.

    Designed to provide insight into the proceedings, transactions, and findings of the Arizona Commission of Indian Affairs, this 1980-81 annual report reflects the commission's efforts to act in a liaison capacity between tribes and state government to provide tribes with technical assistance. The report describes 18 projects completed during the…

  2. Arizona Commission of Indian Affairs 1984 Annual Report.

    Science.gov (United States)

    Arizona Commission of Indian Affairs, Phoenix.

    Designed to provide insight into the Arizona Commission of Indian Affairs' proceedings, transactions, and findings, the 1984 annual report describes the year's efforts to improve communications, understanding, and working relationships between all concerned. After reviewing Commission meeting attendance and the attendance of related meetings, the…

  3. Arizona State University: Student Tracking in a University System.

    Science.gov (United States)

    Porter, John D.; Gebel, Melinda A.

    1995-01-01

    Arizona State University has created longitudinal student files capable of tracking each student's curricular and financial aid history from entry until graduation. The structure of the files, their creation and maintenance, and their evolution over the years are described. Uses of the files to conduct different kinds of studies to inform…

  4. Shape measurements of volcanic particles by CAMSIZER

    OpenAIRE

    Lo Castro, Maria Deborah; Andronico, Daniele; Nunnari, Giuseppe; Spata, Alessandro; Torrisi, Alessio

    2009-01-01

    The shape of volcanic particles is an important parameter holding information related to physical and geochemical processes. The study of particle shape may help improving knowledge on the main eruptive processes (fragmentation, transport and sedimentation) during explosive activity. In general, volcanic ash is formed by different components, namely juvenile, lithic and crystal particles, each one characterized by peculiar morphology. Moreover, quantifying the shape of pyroclasts is needed by...

  5. About the Mechanism of Volcanic Eruptions

    CERN Document Server

    Nechayev, Andrei

    2012-01-01

    A new approach to the volcanic eruption theory is proposed. It is based on a simple physical mechanism of the imbalance in the system "magma-crust-fluid". This mechanism helps to explain from unified positions the different types of volcanic eruptions. A criterion of imbalance and magma eruption is derived. Stratovolcano and caldera formation is analyzed. High explosive eruptions of the silicic magma is discussed

  6. Ground Water in the Wapatki and Sunset Crater National Monuments, Coconino County, Arizona

    Science.gov (United States)

    Cosner, Oliver J.

    1962-01-01

    The Wupatki and Sunset Crater National Monuments are 15 and 30 miles, respectively, northeast of Flagstaff on the San Francisco Plateau. They are in the eastern part of the San Francisco volcanic field and on the southwest flank of the Black Mesa basin. The Supai formation, Coconino sandstone, Kaibab limestone, Moenkopi formation, and Chinle formation are overlain in parts of the area by volcanic rocks and alluvium. The regional water table occurs chiefly in the Coconino sandstone at altitudes of about 5,000 feet at Sunset Crater, about 4,075 feet near Wupatki Ruin, and about 4,100 feet near Citadel Ruin. The general movement of the ground water is northeastward. Small supplies of perched water occur in the Moenkopi formation and in the alluvium, and perched water may be present locally in the volcanic rocks. The results of the field investigation indicated that adequate ground-water supplies were available from the Coconino sandstone to meet the needs of the National Monuments, and a well was drilled at the Wupatki Monument headquarters in 1958 to a total depth of 904 feet. It produced 50 gpm (gallons per minute) of water with 45 feet of drawdown from a static water level of 780 feet below land surface.

  7. Verification of land cover maps from LANDSAT data. [for Alaska, Arizona and Oklahoma

    Science.gov (United States)

    Linden, D. S.; Szajgin, J.

    1981-01-01

    The application of cluster sampling to verifying the accuracy of maps derived from digital data is discussed. Variants of the cluster sampling technique were used in large scale assessments for areas in excess of one million hectares. Three types of classification errors are possible: commission errors, omission errors, and overall error classification. Commission errors for a particular cover type occur when pixels are classified as that cover type but are found to be some other cover type when the field is checked. Omission errors occur when pixels of fields already visited and known to be of a particular cover type, are classified as some other cover type. Overall error is the proportion of pixels incorrectly classified, without regard to omission or commission. Since the classified image represents the sampling frame, sampling for accuracy assessment was designed to estimate commission error. However, the sample can also provide useful estimates of omission and overall error. Assessment for Alaska, Arizona, and Oklahoma are presented.

  8. A multidisciplinary approach to quantify the permeability of the Whakaari/White Island volcanic hydrothermal system (Taupo Volcanic Zone, New Zealand)