Across-shelf sediment transport since the Last Glacial Maximum, southern California margin
C.K. Sommerfield, H.J. Lee
2004, Geology (32) 345-348
Correlation of continental shelf-slope stratigraphy in Santa Monica Bay (southern California) with Ocean Drilling Program records for nearby slope-basin sites has illuminated the timing and scale of terrigenous sediment dispersal on margin since the Last Glacial Maximum (LGM). Marine flooding surfaces preserved in a transgressive sequence on the Santa Monica...
Decompression experiments identify kinetic controls on explosive silicic eruptions
M. T. Mangan, T. W. Sisson, W.B. Hankins
2004, Geophysical Research Letters (31)
Eruption intensity is largely controlled by decompression‐induced release of water‐rich gas dissolved in magma. It is not simply the amount of gas that dictates how forcefully magma is propelled upwards during an eruption, but also the rate of degassing, which is partly a function of the supersaturation pressure (ΔPcritical) triggering...
Habitat changes: Mount Haggin Wildlife Management Area
M.R. Frisina, R.B. Keigley
2004, Rangelands (26) 3-13
In 1984, a rest-rotation grazing system was established on the Mount Haggin Wildlife Management Area (MHWMA) in southwest Montana. The area is a mixture of wet and dry meadow types, grass/shrublands, and forest. Prior to implementing the grazing system, photo-monitoring points were established on the MHWMA at locations were cattle...
Determining nest predators of the Least Bell's Vireo through point counts, tracking stations, and video photography
Bonnie L. Peterson, Barbara E. Kus, Douglas H. Deutschman
2004, Journal of Field Ornithology (75) 89-95
We compared three methods to determine nest predators of the Least Bell's Vireo (Vireo bellii pusillus) in San Diego County, California, during spring and summer 2000. Point counts and tracking stations were used to identify potential predators and video photography to document actual nest predators. Parental behavior at depredated nests...
Analysis of predator movement in prairie landscapes with contrasting grassland composition
M.L. Phillips, W.R. Clark, S.M. Nusser, M.A. Sovada, R. J. Greenwood
2004, Journal of Mammalogy (85) 187-195
Mammalian predation influences waterfowl breeding success in the U.S. northern Great Plains, yet little is known about the influence of the landscape on the ability of predators to find waterfowl nests. We used radiotelemetry to record nightly movements of red foxes (Vulpes vulpes) and striped skunks (Mephitis mephitis) in two...
Effects of an introduced pathogen and fire exclusion on the demography of sugar pine
Phillip J. van Mantgem, Nathan L. Stephenson, MaryBeth Keifer, Jon E. Keeley
2004, Ecological Applications (14) 1590-1602
An introduced pathogen, white pine blister rust (Cronartium ribicola), has caused declines in five-needled pines throughout North America. Simultaneously, fire exclusion has resulted in dense stands in many forest types, which may create additional stress for these generally shade-intolerant pines. Fire exclusion also allows fuels to accumulate, and it...
High resolution paleoceanography of the Guaymas Basin, Gulf of California, during the past 15 000 years
J.A. Barron, D. Bukry, J. L. Bischoff
2004, Marine Micropaleontology (50) 185-207
Deep Sea Drilling Project Site 480 (27??54.10???N, 111??39.34???W; 655 m water depth) contains a high resolution record of paleoceanographic change of the past 15 000 years for the Guaymas Basin, a region of very high diatom productivity within the central Gulf of California. Analyses of diatoms and silicoflagellates were completed...
Seawater chemistry and the advent of biocalcification
S.T. Brennan, T.K. Lowenstein, J. Horita
2004, Geology (32) 473-476
Major ion compositions of primary fluid inclusions from terminal Proterozoic (ca. 544 Ma) and Early Cambrian (ca. 515 Ma) marine halites indicate that seawater Ca2+ concentrations increased approximately threefold during the Early Cambrian. The timing of this shift in seawater chemistry broadly coincides with the "Cambrian explosion," a brief drop...
Degradates provide insight to spatial and temporal trends of herbicides in ground water
D.W. Kolpin, D.J. Schnoebelen, E.M. Thurman
2004, Groundwater (42) 601-608
Since 1995, a network of municipal wells in Iowa, representing all major aquifer types (alluvial, bedrock/karst region, glacial drift, bedrock/nonkarst region), has been repeatedly sampled for a broad suite of herbicide compounds yielding one of the most comprehensive statewide databases of such compounds currently available in the United States. This...
Consumption dynamics of the adult piscivorous fish community in Spirit Lake, Iowa
H. Liao, C.L. Pierce, J. G. Larscheid
2004, North American Journal of Fisheries Management (24) 890-902
At Spirit Lake, one of Iowa's most important fisheries, walleye Sander vitreus (formerly Stizostedion vitreum) is one of the most popular species with anglers. Despite a century of walleye stocking and management in Spirit Lake, walleye growth rate, size structure, and angler harvest continue to decline. Our purpose was to...
Geochemical characterization of tarballs on beaches along the California coast. Part I - Shallow seepage impacting the Santa Barbara Channel Islands, Santa Cruz, Santa Rosa and San Miguel
F. D. Hostettler, R.J. Rosenbauer, T.D. Lorenson, J. Dougherty
2004, Organic Geochemistry (35) 725-746
Tarballs are common along the southern California coastline. This study investigates tarballs from beaches along this coastline, with a focus on Santa Cruz, Santa Rosa, and San Miquel Islands in the Santa Barbara Channel. The tarballs were fingerprinted using biomarker and stable carbon isotope parameters, and then grouped according to...
Scale effects on headwater catchment runoff timing, flow sources, and groundwater‐streamflow relations
Brian L. McGlynn, Jeffery J. McDonnell, Jan Seibert, Carol Kendall
2004, Water Resources Research (40)
The effects of catchment size and landscape organization on runoff generation are poorly understood. Little research has integrated hillslope and riparian runoff investigation across catchments of different sizes to decipher first‐order controls on runoff generation. We investigated the role of catchment sizes on riparian and hillslope dynamics based on hydrometric...
Multistage hydrothermal silicification and Fe-Tl-As-Sb-Ge-REE enrichment in the Red Dog Zn-Pb-Ag district, northern Alaska: Geochemistry, origin, and exploration applications
J. F. Slack, K.D. Kelley, V.M. Anderson, J.L. Clark, R. A. Ayuso
2004, Economic Geology (99) 1481-1508
Geochemical analyses of major, trace, and rare earth elements (REE) in more than 200 samples of variably silicified and altered wall rocks, massive and banded sulfide, silica rock, and sulfide-rich and unmineralized barite were obtained from the Main, Aqqaluk, and Anarraaq deposits in the Red Dog Zn-Pb-Ag district of northern...
Surface rupture of the 2002 Denali fault, Alaska, earthquake and comparison with other strike-slip ruptures
Peter J. Haeussler, David P. Schwartz, T. E. Dawson, Heidi D. Stenner, J. J. Lienkaemper, F. Cinti, Paola Montone, B. Sherrod, P. Craw
2004, Earthquake Spectra (20) 565-578
On 3 November 2002, an M7.9 earthquake produced 340 km of surface rupture on the Denali and two related faults in Alaska. The rupture proceeded from west to east and began with a 40-km-long break on a previously unknown thrust fault. Estimates of surface slip on this thrust are 3-6...
Spatial variations in the frequency-magnitude distribution of earthquakes at Mount Pinatubo volcano
J.J. Sanchez, S.R. McNutt, J.A. Power, M. Wyss
2004, Bulletin of the Seismological Society of America (94) 430-438
The frequency-magnitude distribution of earthquakes measured by the b-value is mapped in two and three dimensions at Mount Pinatubo, Philippines, to a depth of 14 km below the summit. We analyzed 1406 well-located earthquakes with magnitudes MD ???0.73, recorded from late June through August 1991, using the maximum likelihood method....
An association of benthic foraminifera and gypsum in Holocene sediments of estuarine Chesapeake Bay, USA
J. Cann, T. Cronin
2004, Holocene (14) 614-620
Two cores of Holocene sediments recovered from the Cape Charles Channel of Chesapeake Bay yielded radiocarbon ages of about 6.8 to 5.8 ka for the lower intervals. Fossil foraminifera preserved in these lower sediments are dominated by species of Elphidium, which make up about 90% of the assemblage throughout, and...
Hydrogeologic processes of large-scale tectonomagmatic complexes in Mongolia-southern Siberia and on Mars
G. Komatsu, J. M. Dohm, T.M. Hare
2004, Geology (32) 325-328
Large-scale tectonomagmatic complexes are common on Earth and Mars. Many of these complexes are created or at least influenced by mantle processes, including a wide array of plume types ranging from superplumes to mantle plumes. Among the most prominent complexes, the Mongolian plateau on Earth and the Tharsis bulge on...
Weak top-down control of grazers and periphyton by slimy sculpins in a coldwater stream
Carl R. Ruetz III, B. Vondracek, R.M. Newman
2004, Journal of the North American Benthological Society (23) 271-286
We conducted an enclosure/exclosure experiment during summer 1998 and 1999 to test the strength of top-down control by slimy sculpins (Cottus cognatus) on benthic macroinvertebrates and periphyton. We used 1-m2 cages to manipulate slimy sculpin density within 6 riffles in Valley Creek, Minnesota. Each riffle contained an enclosure stocked with...
Evaluation of coalbed gas potential of the Seelyville Coal Member, Indiana, USA
A. Drobniak, Maria Mastalerz, J. Rupp, N. Eaton
2004, International Journal of Coal Geology (57) 265-282
The Seelyville Coal Member of the Linton Formation in Indiana potentially contains 0.03 trillion m3 (1.1 TCF) of coalbed gas. The gas content determined by canister desorption technique ranges from 0.5 to 5.7 cm3/g on dry ash free basis (15.4 to 182.2 scf/ton). The controls on gas content distribution are...
Driving mechanisms for >40 km of exhumation during contraction and extension in a continental arc, Cascades core, Washington
Scott R. Paterson, R.B. Miller, H. Alsleben, D.L. Whitney, P.M. Valley, H. Hurlow
2004, Tectonics (23)
In the NW North American Cordillera, the Cascades core region of the Coast Plutonic Complex underwent Late Cretaceous (>96 Ma to locally 73 Ma) SW-NE contraction and crustal thickening followed by dextral transpression (???73 to 55 Ma), then transtension (<55 Ma). Exhumation occurred during all three phases. During contraction, slow...
El Nino influence on Holocene reef accretion in Hawai'i
J. Rooney, C. Fletcher, E. Grossman, M. Engels, M. Field
2004, Pacific Science (58) 305-324
New observations of reef accretion from several locations show that in Hawai'i accretion during early to middle Holocene time occurred in areas where today it is precluded by the wave regime, suggesting an increase in wave energy. Accretion of coral and coralline algae reefs in the Hawaiian Islands today is...
A precise method for the analysis of δ18O of dissolved inorganic phosphate in seawater
K. McLaughlin, S. Silva, C. Kendall, Hilary Stuart-Williams, A. Paytan
2004, Limnology and Oceanography: Methods (2) 202-212
A method for preparation and analysis of the oxygen isotope composition (δ18O) of dissolved inorganic phosphate (DIP) has been developed and preliminary results for water samples from various locations are reported. Phosphate is extracted from seawater samples by coprecipitation with magnesium hydroxide. Phosphate is further purified through a series of...
Flow resistance and suspended load in sand-bed rivers: Simplified stratification model
S. Wright, G. Parker
2004, Journal of Hydraulic Engineering (130) 796-805
New methods are presented for the prediction of the flow depth, grain-size specific near-bed concentration, and bed-material suspended sediment transport rate in sand-bed rivers. The salient improvements delineated here all relate to the need to modify existing formulations in order to encompass the full range of sand-bed rivers, and in...
Assessing biodiversity in Nuevo Leon, Mexico: Are nature reserves the answer?
Cesar Cantu, R. Gerald Wright, J. Michael Scott, Eva Strand
2004, Natural Areas Journal (24) 150-153
The Mexican state of Nuevo Leon, located in the northeastern portion of the country, currently has 26 state and three federal nature reserves covering approximately 4.5% of its land area. These reserves were established for a variety of reasons not necessarily related to conservation purposes. In 2000 in response to...
A GIS analysis of suitability for construction aggregate recycling sites using regional transportation network and population density features
G.R. Robinson Jr., K. E. Kapo
2004, Resources, Conservation and Recycling (42) 351-365
Aggregate is used in road and building construction to provide bulk, strength, support, and wear resistance. Reclaimed asphalt pavement (RAP) and reclaimed Portland cement concrete (RPCC) are abundant and available sources of recycled aggregate. In this paper, current aggregate production operations in Virginia, Maryland, and the District of Columbia are...
