Osmium isotopes and silver as tracers of anthropogenic metals in sediments from Massachusetts and Cape Cod bays
G.E. Ravizza, Michael H. Bothner
1996, Geochimica et Cosmochimica Acta (60) 2753-2763
High concentrations of osmium (Os) and silver (Ag) and low 187Os/186Os ratios in Boston sewage make these elements sensitive tracers of the influence of sewage on marine sediments in Massachusetts and Cape Cod bays. Pristine marine sediments have Ag concentrations more than 200 times lower than sewage sludge, Os concentrations...
A catastrophic flood caused by drainage of a caldera lake at Aniakchak Volcano, Alaska, and implications for volcanic hazards assessment
C. F. Waythomas, J. S. Walder, R. G. McGimsey, C.A. Neal
1996, Geological Society of America Bulletin (108) 861-871
Aniakchak caldera, located on the Alaska Peninsula of southwest Alaska, formerly contained a large lake (estimated volume 3.7 × 109 m3) that rapidly drained as a result of failure of the caldera rim sometime after ca. 3400 yr B.P. The peak discharge of the resulting flood was estimated using three methods:...
Numerical simulation of widening and bed deformation of straight sand-bed rivers. II: Model evaluation
S.E. Darby, Colin R. Thorne, A. Simon
1996, Journal of Hydraulic Engineering (122) 194-202
In this paper the numerical model presented in the companion paper is tested and applied. Assessment of model accuracy was based on two approaches. First, predictions of evolution of a 13.5 km reach of the South Fork of the Forked Deer River, in west Tennessee, were compared to observations over...
New USGS seismic hazard maps for the United States
A. Frankel, C. Mueller, D. Perkins, T. Barnhard, E. Leyendecker, E. Safak, S. Hanson, N. Dickman, M. Hopper
Housner G.W.Chung R.M., editor(s)
1996, Conference Paper, Proceedings of the Conference on Natural Disaster Reduction
The US Geological Survey (USGS) is preparing new seismic national maps for release in April 1996. The new maps plot probabilistic ground motions for return times of about 500, 1000, and 2500 years. Deterministic (scenario) ground-motion maps are being prepared for selected faults in the western US. Due to the...
Uranium adsorption on ferrihydrite - Effects of phosphate and humic acid
T.E. Payne, J.A. Davis, T.D. Waite
1996, Radiochimica Acta (74) 239-243
Uranium adsorption on ferrihydrite was studied as a function of pH in systems equilibrated with air, in the presence and absence of added phosphate and humic acid (HA). The objective was to determine the influence of PO43- and HA on...
Improved method for measuring water imbibition rates on low-permeability porous media
M.D. Humphrey, J.D. Istok, L. E. Flint, A. L. Flint
1996, Soil Science Society of America Journal (60) 28-34
Existing methods for measuring water imbibition rates are inadequate when imbibition rates are small (e.g., clay soils and many igneous rocks). We developed an improved laboratory method for performing imbibition measurements on soil or rock cores with a wide range of hydraulic properties. Core specimens are suspended from an electronic...
Inferring shallow groundwater flow in saprolite and fractured rock using environmental tracers
P.G. Cook, D. K. Solomon, W. E. Sanford, E. Busenberg, Niel Plummer, R.J. Poreda
1996, Water Resources Research (32) 1501-1509
The Ridge and Valley Province of eastern Tennessee is characterized by (1) substantial topographic relief, (2) folded and highly fractured rocks of various lithologies that have low primary permeability and porosity, and (3) a shallow residuum of medium permeability and high total porosity. Conceptual models of shallow groundwater flow and...
Geochemistry of aquatic humic substances in the Lake Fryxell basin, Antarctica
G. Aiken, D. McKnight, R. Harnish, R. Wershaw
1996, Biogeochemistry (34) 157-188
Dissolved organic carbon (DOC) in Lake Fryxell, 10 streams flowing into the lake, and the moat surrounding the lake was studied to determine the influence of sources and biogeochemical processes on its distribution and chemical nature. Lake Fryxell is an amictic, permanently ice-covered lake in the McMurdo Dry Valleys which...
A scan-angle correction for thermal infrared multispectral data using side lapping images
K. Watson
1996, Geophysical Research Letters (23) 2421-2424
Thermal infrared multispectral scanner (TIMS) images, acquired with side lapping flight lines, provide dual angle observations of the same area on the ground and can thus be used to estimate variations in the atmospheric transmission with scan angle. The method was tested using TIMS aircraft data...
Recent volcanism in the Siqueiros transform fault: Picritic basalts and implications for MORB magma genesis
M.R. Perfit, D.J. Fornari, W.I. Ridley, P.D. Kirk, John F. Casey, K.A. Kastens, J.R. Reynolds, M. Edwards, D. Desonie, R. Shuster, S. Paradis
1996, Earth and Planetary Science Letters (141) 91-108
Small constructional volcanic landforms and very fresh-looking lava flows are present along one of the inferred active strike-slip faults that connect two small spreading centers (A and B) in the western portion of the Siqueiros transform domain. The most primitive lavas (picritic and olivine-phyric basalts), exclusively recovered from the young-looking...
Seismic velocities for hydrate-bearing sediments using weighted equation
Myung W. Lee, D. R. Hutchinson, T. S. Collett, William P. Dillon
1996, Journal of Geophysical Research B: Solid Earth (101) 20347-20358
A weighted equation based on the three-phase time-average and Wood equations is applied to derive a relationship between the compressional wave (P wave) velocity and the amount of hydrates filling the pore space. The proposed theory predicts accurate P wave velocities of marine sediments in the porosity range of 40-80%...
Global distribution of beryllium isotopes in deep ocean water as derived from Fe-Mn crusts
F. Von Blanckenburg, R. K. O’Nions, N.S. Belshaw, A. Gibb, J.R. Hein
1996, Earth and Planetary Science Letters (141) 213-226
The direct measurement of the ratio of cosmogenic 10Be (T12= 1.5 Ma">T12= 1.5 Ma) to stable terrigenously sourced 9Be in deep seawater or marine deposits can be used to trace water mass movements and to quantify the incorporation of trace metals into the deep sea. In...
Serum factors as indicators of environmental stress: optimization of methodologies for striped bass
V. S. Blazer, D.L. Higginbotham, J.W. Fournie
J.S. Stolen, T.C. Fletcher, D. P. Anderson, J.T. Zelikoff, L.E. Twerdok, S.L. Kaattari, C.C. Bayne, editor(s)
1996, Book chapter, Modulators of Fish Immune Responses: Volume 1, Models for Environmental Toxicology, Biomarkers, Immunostimulators
No abstract available at this time...
Late Pliocene diatoms in a diatomite from Prydz Bay, East Antarctica
A.D. Mahood, J.A. Barron
1996, Micropaleontology (42) 285-302
Very well-preserved Pliocene diatoms from a diatomite unit interbedded within glacial sediments at Ocean Drilling Program Site 742 in Prydz Bay, Antarctica are documented and illustrated. The presence of Thalassiosira kolbei, T. torokina, Actinocyclus actinochilus, A. karstenii and the absence of Nitzschia interfrigidaria. T. insigna and T. vulnifica in Sample...
Paleomagnetism of Jurassic radiolarian chert above the Coast Range ophiolite at Stanley Mountain, California, and implications for its paleogeographic origins
J.T. Hagstrum, B.L. Murchey
1996, Geological Society of America Bulletin (108) 643-652
Upper Jurassic red tuffaceous chert above the Coast Range ophiolite at Stanley Mountain, California (lat 35°N, long 240°E), contains three components of remanent magnetization. The first component (A; removed by ≈100–≈200°C) has a direction near the present-day field for southern California and is...
Thermodynamic properties of scapolites at temperatures ranging from 10 K to 1000 K
N. Komada, D.P. Moecher, E.F. Westrum Jr., B. S. Hemingway, M. Yu Zolotov, Y.V. Semenov, I.L. Khodakovsky
1996, Journal of Chemical Thermodynamics (28) 941-973
The heat capacities of five mineral samples from the scapolite solid-solution series, Na4Al3Si9O24Cl (marialite) to Ca4Al6Si6O24CO3 (meionite), were measured by the adiabatic method from T=8 K to T=350 K and by the differential scanning calorimetry (d.s.c.) method from T = 300 K to T = 1000 K. The meionite (Me)...
Evaluating the reliability of the stream tracer approach to characterize stream-subsurface water exchange
Judson W. Harvey, Brian J. Wagner, Kenneth E. Bencala
1996, Water Resources Research (32) 2441-2451
Stream water was locally recharged into shallow groundwater flow paths that returned to the stream (hyporheic exchange) in St. Kevin Gulch, a Rocky Mountain stream in Colorado contaminated by acid mine drainage. Two approaches were used to characterize hyporheic exchange: sub-reach-scale measurement of hydraulic heads and hydraulic conductivity to compute...
Modeling reservoir density underflow and interflow from a chemical spill
Ruochuan Gu, Steve C. McCutcheon, Pei-Fang Wang
1996, Water Resources Research (32) 695-705
An integral simulation model has been developed for understanding and simulating the process of a density current and the transport of spilled chemicals in a stratified reservoir. The model is capable of describing flow behavior and mixing mechanisms in different flow regimes (plunging flow, underflow, and interflow). It computes flow...
The upper mantle structure of the central Rio Grande rift region from teleseismic P and S wave travel time delays and attenuation
P.D. Slack, P.M. Davis, W.S. Baldridge, K.H. Olsen, A. Glahn, U. Achauer, W. Spence
1996, Journal of Geophysical Research B: Solid Earth (101) 16003-16023
The lithosphere beneath a continental rift should be significantly modified due to extension. To image the lithosphere beneath the Rio Grande rift (RGR), we analyzed teleseismic travel time delays of both P and S wave arrivals and solved for the attenuation of P and S waves for four seismic experiments spanning the Rio Grande rift. Two tomographic inversions...
Residence time of water discharging from the Hanging Gardens of Zion Park
B. A. Kimball, P.K. Christensen
1996, Water Resources Bulletin (32) 531-540
The Hanging Gardens are a unique feature of Zion National Park. Knowledge of the source and residence time of water discharging from the Hanging Gardens is necessary to help preserve these features. Ground-water chemical and isotopic data distinguish the discharge from seeps and springs into two groups, one of low...
Uranium-series dating of carbonate (tufa) deposits associated with quaternary fluctuations of Pyramid Lake, Nevada
Barney J. Szabo, C. A. Bush, L. V. Benson
1996, Quaternary Research (45) 271-281
Uranium-series dating of dense tufa deposited in a small cave, at former lake margins, and in large tufa mounds clarifies the timing of lake-level variation during the past 400,000 yr in the Pyramid Lake basin. A moderate-sized lake occasionally overflowed the Emerson Pass sill at elevation of ???1207 m between...
Imaging the San Andreas fault with explosion and earthquake sources
C. Thurber, S. Roecker, W. Lutter, W. Ellsworth
1996, Eos, Transactions, American Geophysical Union (77) 45-48
Mounting evidence suggests that fault zone heterogeneity may play a crucial role in the localization of rupture in earthquakes [Aki, 1995]. The heterogeneity can take several forms: spatial variations in physical properties (elastic properties, pore fluid pressure, etc.) or complexity in the fault surface (bends, offsets, etc.). High-resolution, three-dimensional models...
Block and shear-zone architecture of the Minnesota River Valley subprovince: Implications for late Archean accretionary tectonics
D. L. Southwick, V.W. Chandler
1996, Canadian Journal of Earth Sciences (33) 831-847
The Minnesota River Valley subprovince of the Superior Province is an Archean gneiss terrane composed internally of four crustal blocks bounded by three zones of east-northeast-trending linear geophysical anomalies. Two of the block-bounding zones are verified regional-scale shears. The geological nature of the third boundary has not been established. Potential-field...
The reversibility of virus attachment to mineral surfaces
J.P. Loveland, J. N. Ryan, G.L. Amy, R.W. Harvey
1996, Colloids and Surfaces A: Physicochemical and Engineering Aspects (107) 205-221
Virus transport through groundwater is limited by attachment to mineral surfaces and inactivation. Current virus transport models do not consider the implications of the reversibility of virus attachment to minerals. To explore the reversibility of virus attachment to mineral surfaces, we attached PRD1, a bacteriophage considered to be a good...
Quantitative investigations of the Missouri gravity low: A possible expression of a large, Late Precambrian batholith intersecting the New Madrid seismic zone
T.G. Hildenbrand, A. Griscom, W. R. Van Schmus, W.D. Stuart
1996, Journal of Geophysical Research B: Solid Earth (101) 21921-21942
Analysis of gravity and magnetic anomaly data helps characterize the geometry and physical properties of the source of the Missouri gravity low, an important cratonic feature of substantial width (about 125 km) and length (> 600 km). Filtered anomaly maps show that this prominent feature extends NW from the Reelfoot...
