Phytoplankton productivity in relation to light intensity: A simple equation
D. H. Peterson, M.J. Perry, K.E. Bencala, M.C. Talbot
1987, Estuarine, Coastal and Shelf Science (24) 813-832
A simple exponential equation is used to describe photosynthetic rate as a function of light intensity for a variety of unicellular algae and higher plants where photosynthesis is proportional to (1-e−β1). The parameter β (=Ik−1">=Ik−1) is derived by a simultaneous curve-fitting method, where I is incident...
Man-induced gradient adjustment of the South Fork Forked Deer River, west Tennessee
A. Simon, C. H. Robbins
1987, Environmental Geology and Water Sciences (9) 109-118
Channel modifications from 1968 to 1969 on the South Fork Forked Deer River in western Tennessee have caused upstream degradation, downstream aggradation, and bank failures along the altered channels, adjacent reaches, and tributaries. The result of these adjustments is a general decrease in gradient as the channel attempts to absorb...
A study of metal ion adsorption at low suspended-solid concentrations
Cecily C.Y. Chang, J.A. Davis, James S. Kuwabara
1987, Estuarine, Coastal and Shelf Science (24) 419-424
A procedure for conducting adsorption studies at low suspended solid concentrations in natural waters (<50 mg l−1) is described. Methodological complications previously associated with such experiments have been overcome. Adsorption of zinc ion onto synthetic colloidal titania (TiO2) was studied as a function...
Evolution, biogeography, and systematics of Puriana: evolution and speciation in Ostracoda, III.
T. M. Cronin
1987, Journal of Paleontology (61)
Three types of geographic isolation—land barriers, deep water barriers, and climatic barriers—resulted in three distinct evolutionary responses in Neogene and Quaternary species of the epineritic ostracode genus Puriana. Through systematic, paleobiogeographic, and morphologic study of several hundred fossil and Recent populations from the eastern Pacific, western Atlantic,...
Lungfish burrows in the Upper Triassic Chinle and Dolores Formations, Colorado Plateau
R. F. Dubiel, R.H. Blodgett, T. M. Bown
1987, Journal of Sedimentary Petrology (57) 512-521
Vertical-to-inclined, cylindrical trace fossils that occur in the Upper Triassic Chinle and Dolores Formations on the Colorado Plateau are interpreted to be the casts of lungfish burrows. The casts, which are as much as 11 cm in diameter and as much as 1.6...
Archean inheritance in zircon from late Paleozoic granites from the Avalon zone of southeastern New England: An African connection
R. E. Zartman, Hermes O. Don
1987, Earth and Planetary Science Letters (82) 305-315
In southeastern New England the Narragansett Pier Granite locally intrudes Carboniferous metasedimentary rocks of the Narragansett basin, and yields a monazite UPb Permian emplacement age of 273 ± 2Ma. Zircon from the Narragansett Pier Granite contains a...
Depth-averaging effects on hydraulic head for media with stochastic hydraulic conductivity
R.L. Naff, A. V. Vecchia
1987, Water Resources Research (23) 561-570
Hydraulic conductivity of a porous medium frequently is considered to be a single realization of a three-dimensional spatial stochastic process. The most common observations of flow in porous media are hydraulic-head measurements obtained from wells which are screened over extensive sections of the medium. These measurements represent, approximately, a one-dimensional...
The effects of early diagenesis on the chemical and stable carbon isotopic composition of wood
E.C. Spiker, Patrick G. Hatcher
1987, Geochimica et Cosmochimica Acta (51) 1385-1391
Studies of modern and ancient buried wood show that there is a linear correlation between carbohydrate content and the stable carbon isotope composition as carbohydrates are preferentially degraded during early diagenesis. As the carbohydrate content decreases, the δ13C">δ13C value of the degraded wood decreases 1 to...
Effect of transmitter turn-off time on transient soundings
David V. Fitterman, Walter L. Anderson
1987, Geoexploration (24) 131-146
A general procedure for computing the effect of non-zero turn-off time on the transient electromagnetic response is presented which can be applied to forward and inverse calculation methods for any transmitter-receiver configuration. We consider in detail the case of a large transmitter loop which has a receiver coil located at...
An oxygen isotope model for interpreting carbonate diagenesis in nonmarine rocks (Green River Basin, Wyoming, USA)
W. W. Dickinson
1987, Chemical Geology (65) 103-116
A closed-system model is used for predicting the δ18O of formation waters in the deep portions of the northern Green River basin, Wyoming. δ18Ocalcite is calculated from this modeled water and compared with the δ18O of measured calcites to help interpret diagenesis in the basin.The modification of 18Owater, which may be caused...
Microprocessor-based data-acquisition system for a borehole radar
Jerry A. Bradley, David L. Wright
1987, IEEE Transactions on Geoscience and Remote Sensing (GE-25) 441-447
An efficient microprocessor-based system has been implemented that permits real-time acquisition, stacking, and digital recording of data generated by a borehole radar system. Although the system digitizes, stacks, and records independently of a computer, it is interfaced to a desktop computer for program control over system parameters such as sampling...
The distribution of nitrogen species and adsorption of ammonium in sediments from the tidal Potomac River and estuary
N.S. Simon, M.M. Kennedy
1987, Estuarine, Coastal and Shelf Science (25) 11-26
The distribution of dissolved ammonium, adsorbed ammonium and residual, organic and total nitrogen was measured in Potomac River tidal, transition zone and lower estuary sediments to a depth of 66 cm. For these sediments, exchangeable ammonium, and thereby adsorbed ammonium concentrations, were determined directly using an ammonia electrode in alkaline...
PHYSICAL MODELING OF CONTRACTED FLOW.
Jonathan K. Lee
1987, Conference Paper
Experiments on steady flow over uniform grass roughness through centered single-opening contractions were conducted in the Flood Plain Simulation Facility at the U. S. Geological Survey's Gulf Coast Hydroscience Center near Bay St. Louis, Miss. The experimental series was designed to provide data for calibrating and verifying two-dimensional, vertically averaged...
SEA-ICE INFLUENCE ON ARCTIC COASTAL RETREAT.
Erk Reimnitz, P. W. Barnes
1987, Conference Paper
Recent studies document the effectiveness of sea ice in reshaping the seafloor of the inner shelf into sharp-relief features, including ice gouges with jagged flanking ridges, ice-wallow relief, and 2- to 6-m-deep strudel-scour craters. These ice-related relief forms are in disequilibrium with classic open-water hydraulic processes and thus are smoothed...
Stable isotope compositions and water contents of boninite series volcanic rocks from Chichi-jima, Bonin Islands, Japan
P.F. Dobson, J. R. O’Neil
1987, Earth and Planetary Science Letters (82) 75-86
Measurements of stable isotope compositions and water contents of boninite series volcanic rocks from the island of Chichi-jima, Bonin Islands, Japan, confirm that a large amount (1.6–2.4 wt.%) of primary water was present in these unusual magmas. An enrichment of 0.6‰...
On predicting changes in the geomagnetic field
L.R. Alldredge
1987, Journal of Geophysical Research Solid Earth (92) 6331-6338
The present method of using constant secular variation rates to forecast magnetic components at a given site or to forecast spherical harmonic coefficients is known to be inaccurate. A new predictive method using trend and trigonometric functions fitted to known past values is used to extrapolate for a few years...
Maestrichtian benthic foraminifers from Ocean Point, North Slope, Alaska ( USA).
K. McDougall
1987, Journal of Foraminiferal Research (17) 344-366
Previous studies of fauna and flora from Ocean Point, Alaska, have suggested ages ranging from Campanian to early Eocene and that these assemblages are either highly endemic or commonplace. I demonstrate that the moderately abundant benthic foraminifers constitute early Maestrichtian boreal assemblages common to Canada and northern Europe. Paleoenvironmental analysis...
Geological setting of U.S. fossil fuels.
C.D. Masters, R. F. Mast
1987, Episodes (10) 308-313
The USA has a special position in terms of fossil fuel development. Not only is it one of the most important nations in terms of resources of oil, gas and coal, but it has also been by far the dominant producer and consumer. In this thorough review of the regional...
Basin-ring spacing on the Moon, Mercury, and Mars
R.J. Pike, P. D. Spudis
1987, Earth, Moon and Planets (39) 129-194
Radial spacing between concentric rings of impact basins that lack central peaks is statistically similar and nonrandom on the Moon, Mercury, and Mars, both inside and outside the main ring. One spacing interval, (2.0 ?? 0.3)0.5D, or an integer multiple of it, dominates most basin rings. Three analytical approaches yield...
The mobilization of aluminum in a natural soil system: Effects of hydrologic pathways
Isabelle M. Cozzarelli, Janet S. Herman, Roderic A. Parnell Jr.
1987, Water Resources Research (23) 859-874
A two-component soil water flow model was used in conjunction with an equilibrium speciation model WATEQF to study aluminum mobility in soils of a forested watershed, White Oak Run, in the Shenandoah National Park, Virginia. Soil solution samples, taken from the O, E, B, C1, and C2horizons, were collected from...
Modes of development of slope canyons and their relation to channel and levee features on the Ebro sediment apron, off-shore northeastern Spain
S. O'Connell, William B. F. Ryan, W. R. Normark
1987, Marine and Petroleum Geology (4)
Six submarine slope canyons in an area of the northwestern Mediterranean, offshore from the Ebro River and Delta, were surveyed with bathymetric swathmapping (SeaBeam) and mid-range side-looking sonar (SeaMARC I). All of the canyons have slightly winding paths with concave-upwards gradients that are relatively steep shallower than 1,200 m. Two...
Role of pressure in smectite dehydration: Effects on geopressure and smectite-to-illite transformation
Virginia Colten-Bradley
1987, American Association of Petroleum Geologists Bulletin (71) 1414-1427
Evaluation of the effect of pressure on the temperature of interlayer water loss (dehydration) by smectites under diagenetic conditions indicates that smectites are stable as hydrated phases in the deep subsurface. Hydraulic and differential pressure conditions affect dehydration differently. Smectites under hydraulic pressure conditions, such as in the pores of...
Modeling and analysis of direct-current electrical resistivity in the Durham Triassic basin, North Carolina
C. Erwin Brown
1987, Geoexploration (24) 429-440
Sixty-two Schlumberger electrical soundings were made in the Durham Triassic basin in an effort to determine basin structural geometry, depth of the sedimentary layers, and spatial distribution of individual rock facies. A digital computer program was used to invert the sounding curves of apparent resistivity versus distance to apparent resistivity...
Mid-Holocene climate in Northern Minnesota
R. M. Forester, L.D. Delorme, J.P. Bradbury
1987, Quaternary Research (28) 263-273
Study of Holocene ostracodes and diatoms from Elk Lake, in North-Central Minnesota, indicates that the local climate of the mid-Holocene can be subdivided into three intervals. Throughout interval 1 (ca. 7800 to 6700 yr B.P.), climate was colder and much drier than today. During intervals 2 and 3 (ca. 6700...
A model for tides and currents in the English Channel and southern North Sea
Roy A. Walters
1987, Conference Paper, Advances in Water Resources
The amplitude and phase of 11 tidal constituents for the English Channel and southern North Sea are calculated using a frequency domain, finite element model. The governing equations - the shallow water equations - are modifed such that sea level is calculated using an elliptic equation of the Helmholz type...
