North American Earth Science Megaproject Continuum, Part 3: New Canadian EON-ROSE Program     

Katherine Boggs  David Eaton  Thomas James  Roy Hyndman  Malaika Ulmi  Pascal Audet  Ed Johnston  Michael Sideris  Ron Clowes  Julie Elliott  Jeff Freymueller  Paul Kushner  Kristin Morell  Derek Schutt  Rick Aster  Frank Vernon  Michael Hedlin  Catherine de Groot-Hedlin  Eric Donovan  Roland Stull 《《地质学报》英文版》2018,92(Z1):12-13

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Variations in population vulnerability to tectonic and landslide-related tsunami hazards in Alaska     

Wood  Nathan J.  Peters  Jeff 《Natural Hazards》2015,75(2):1811-1831

Natural Hazards - Effective tsunami risk reduction requires an understanding of how at-risk populations are specifically vulnerable to tsunami threats. Vulnerability assessments primarily have been...  相似文献   

Simulated effect of soil depth and bedrock topography on near‐surface hydrologic response and slope stability     

Cristiano Lanni  Jeff McDonnell  Luisa Hopp  Riccardo Rigon 《地球表面变化过程与地形》2013,38(2):146-159

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Geochemical indicators of interbasin groundwater flow within the southern Rio Grande Valley, southwestern USA     

Jeff B. Langman  Andre S. Ellis 《Environmental Earth Sciences》2013,68(5):1285-1303

Increased groundwater withdrawals for the growing population in the Rio Grande Valley and likely alteration of recharge to local aquifers with climate change necessitates an understanding of the groundwater connection between the Jornada del Muerto Basin and the adjoining and more heavily used aquifer in the Mesilla Basin. Separating the Jornada and Mesilla aquifers is a buried bedrock high from Tertiary intrusions. This bedrock high or divide restricts and/or retards interbasin flow from the Jornada aquifer into the Mesilla aquifer. The potentiometric surface of the southern Jornada aquifer near part of the bedrock high indicates a flow direction away from the divide because of a previously identified damming effect, but a groundwater outlet from the southern Jornada aquifer is necessary to balance inputs from the overall Jornada aquifer. Differences in geochemical constituents (major ions, δD, δ¹⁸O, δ³⁴S, and ⁸⁷Sr/⁸⁶Sr) indicate a deeper connection between the two aquifers through the Tertiary intrusions where Jornada water is geochemically altered because of a geothermal influence. Jornada groundwater likely is migrating through the bedrock high in deeper pathways formed by faults of the Jornada Fault Zone, in addition to Jornada water that overtops the bedrock high as previously identified as the only connection between the two aquifers. Increased groundwater withdrawals and lowering of the potentiometric surface of the Jornada aquifer may alter this contribution ratio with less overtopping of the bedrock high and a continued deeper flowpath contribution that could potentially increase salinity values in the Mesilla Basin near the divide.  相似文献   

Geometallurgical Modeling at Olympic Dam Mine, South Australia     

Jeff B. Boisvert  Mario E. Rossi  Kathy Ehrig  Clayton V. Deutsch 《Mathematical Geosciences》2013,45(8):901-925

Modeling of geometallurgical variables is becoming increasingly important for improved management of mineral resources. Mineral processing circuits are complex and depend on the interaction of a large number of properties of the ore feed. At the Olympic Dam mine in South Australia, plant performance variables of interest include the recovery of Cu and U₃O₈, acid consumption, net recovery, drop weight index, and bond mill work index. There are an insufficient number of pilot plant trials (841) to consider direct three-dimensional spatial modeling for the entire deposit. The more extensively sampled head grades, mineral associations, grain sizes, and mineralogy variables are modeled and used to predict plant performance. A two-stage linear regression model of the available data is developed and provides a predictive model with correlations to the plant performance variables ranging from 0.65–0.90. There are a total of 204 variables that have sufficient sampling to be considered in this regression model. After developing the relationships between the 204 input variables and the six performance variables, the input variables are simulated with sequential Gaussian simulation and used to generate models of recovery of Cu and U₃O₈, acid consumption, net recovery, drop weight index, and bond mill work index. These final models are suitable for mine and plant optimization.  相似文献   

Photometry of Triton 1992-2004: Surface volatile transport and discovery of a remarkable opposition surge     

B.J. Buratti  J.M. Bauer  J.K. Hillier  H. Hammel  B. Cobb  M. Garsky  J. Foust 《Icarus》2011,212(2):835-846

Triton, the large satellite of Neptune, was imaged by the Voyager 2 spacecraft in 1989 with dark plumes originating in its volatile-rich south polar region. Southern summer solstice, a time when seasonal volatile transport should be at a maximum, occurred in 2001. Ground-based observations of Triton’s rotational light curve obtained from Table Mountain Observatory in 2000-2004 reveal volatile transport on its surface. When compared with a static frost model constructed from Voyager images, the light curve shows an increase in total amplitude. An earlier light curve obtained in 1992 from Mauna Kea Observatory is consistent with the static frost model. This movement of volatiles on the surface agrees with recent imaging results from the Hubble Space Telescope (Bauer, J.M., Buratti, B.J., Li, J.-Y., Mosher, J.A., Hicks, M.D., Schmidt, B.E., Goguen, J.D. [2010]. Astrophys. J. 723, L49-L52). The changes in the light curve can be explained by the transport of nitrogen frost on the surface or by the uncovering of bedrock of less volatile methane. We also find that Triton exhibits a large opposition surge at solar phase angles less than 0.1°. This surge cannot be entirely explained by the effects of coherent backscatter.  相似文献   

Evaluating alternative future sea-level rise scenarios     

Christine C. Shepard  Vera N. Agostini  Ben Gilmer  Tashya Allen  Jeff Stone  William Brooks  Michael W. Beck 《Natural Hazards》2012,63(2):1223-1224

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Responding to Emerging Contaminant Impacts: Situational Management          下载免费PDF全文

Suthan S. Suthersan  John Horst  Ian Ross  Erica Kalve  Joseph Quinnan  Erika Houtz  Jeff Burdick 《Ground Water Monitoring & Remediation》2016,36(3):22-32

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Assessment of perfluorinated compounds (PFCs) in plasma of bottlenose dolphins from two southeast US estuarine areas: relationship with age, sex and geographic locations     

Fair PA  Houde M  Hulsey TC  Bossart GD  Adams J  Balthis L  Muir DC 《Marine pollution bulletin》2012,64(1):66-74

Plasma PFCs were measured in 157 bottlenose dolphins (Tursiops truncatus) sampled from two US southeast Atlantic sites (Charleston (CHS), SC and Indian River Lagoon (IRL), FL) during 2003-2005. ∑PFCs, perfluoroalkyl carboxylates (∑PFCAs), perfluoroalkyl sulfonates (∑PFSAs) and individual compounds were significantly higher in CHS dolphins for all age/sex categories compared to IRL dolphins. Highest ∑PFCs concentrations occurred in CHS juvenile dolphins (2340 ng/g w.w.); significantly higher than found in adults (1570 ng/g w.w. males; 1330 ng/g w.w. females). ∑PFCAs were much greater in CHS dolphins (≈ 21%) compared to IRL dolphins (≈ 7%); ∑PFSAs were 79% in CHS dolphins versus 93% in IRL dolphins. PFOS, the dominant compound, averaged 72% and 84%, respectively, in CHS and IRL dolphins. Decreasing PFC levels occurred with age on the bioaccumulation of PFCs in both sites. These observations suggest PFC accumulation in these two dolphin populations are influenced by site-specific exposures with significantly higher levels in CHS dolphins.  相似文献   

Heterogeneity in mycorrhizal inoculum potential of flood-deposited sediments     

Mary J. Harner  Jeff S. Piotrowski  Ylva Lekberg  Jack A. Stanford  Matthias C. Rillig 《Aquatic Sciences - Research Across Boundaries》2009,71(3):331-337

Riparian areas are diverse systems where flooding creates new sites for establishment of vegetation. Symbioses with soil microorganisms, such as mycorrhizal fungi, affect vascular plant growth and community composition. It is unknown, however, how mycorrhizal fungi are dispersed along rivers and what potential they have to inoculate roots of plants establishing on recently deposited sedimentary surfaces of flood plains. We measured AMF inocula in sediment deposited by an average spring flood along an expansive riverine flood plain in Montana, USA, to determine whether AMF inocula were present in sediments and what types of propagules (spores, hyphae, or colonized root fragments) contribute to AMF infectivity. Flood-deposited sediments contained sufficient inocula for AMF to colonize host plants (Sorghum sudanense) grown in a greenhouse, and both AMF hyphal lengths and spore densities were correlated with infectivity. Availability of mycorrhizal inocula, which is patchily distributed in this system, may lead to microsites that differ in ability to support establishment and growth of early-successional plants.  相似文献