Mass conservation: 1-D open channel flow equations
Lewis L. DeLong
1989, Journal of Hydraulic Engineering (115) 263-269
Unsteady flow simulation in natural rivers is often complicated by meandering channels of compound section. Hydraulic properties and the length of the wetted channel may vary significantly as a meandering river inundates its adjacent floodplain. The one-dimensional, unsteady, open-channel flow equations can be extended to simulate floods in channels of...
Studies of angiospermous wood in Australian brown coal by nuclear magnetic resonance and analytical pyrolysis: New insights into the early coalification process
Patrick G. Hatcher, M. A. Wilson, A. M. Vassallo, H. E. Lerch III
1989, International Journal of Coal Geology (13) 99-126
Many Tertiary coals contain abundant fossilized remains of angiosperms, which commonly dominated the ancient peat-swamp environments; modern analogs of such swamps can be found in tropical and subtropical regions of the world. Comparisons of angiospermous wood from Australian brown coal with...
Sliding behavior and deformation textures of heated illite gouge
Diane E. Moore, R. Summers, J.D. Byerlee
1989, Journal of Structural Geology (11) 329-342
The run products of a series of triaxial friction experiments on an illite-rich gouge have been examined petrographically to study the relationship between textural development and sliding mode. The samples show a complete range of textures, from ones in which the...
Accounting for intracell flow in models with emphasis on water table recharge and stream-aquifer interaction: 1. Problems and concepts
Donald G. Jorgensen, Donald C. Signor, Jeffrey L. Imes
1989, Water Resources Research (25) 669-676
Intracell flow is important in modeling cells that contain both sources and sinks. Special attention is needed if recharge through the water table is a source. One method of modeling multiple sources and sinks is to determine the net recharge per cell. For example, for a model cell containing both...
The ecology of extinctions in kelp forest communities
J. A. Estes, D. O. Duggins, G. B. Rathbun
1989, Conservation Biology (3) 252-264
We recognize three levels of extinction–global, local, and ecological – and provide examples of each. The protection and recovery of sea otters (Enhydra lutris) has provided abundant evidence of the consequences of their local extinction from kelp forest communities in the North Pacifc Ocean. These consequences include release of benthic...
Multiple hydrothermal and metamorphic events in the Kidd Creek volcanogenic massive sulphide deposit, Timmins, Ontario: evidence from tourmalines and chlorites
J. F. Slack, P.R. Coad
1989, Canadian Journal of Earth Sciences (26) 694-715
Tourmaline and chlorite are the principal ferromagnesian silicate minerals in the Kidd Creek massive sulphide deposit. Tourmaline is most common in sphalerite-rich peripheral margins of the chalcopyrite stringer zone. Within the north orebody, samples typically contain <1% tourmaline, but small areas (hand-specimen scale) may have 10–20%. Chlorite is more widely...
Nitrogen cycling between sediment and the shallow-water column in the transition zone of the Potomac River and Estuary. II. The role of wind-driven resuspension and adsorbed ammonium
N.S. Simon
1989, Estuarine, Coastal and Shelf Science (28) 531-547
During periods of sediment resuspension, desorption of ammonium from sediment solids can be the major pathway for enriching the water column with the ammonium that is produced by bacterial degradation of organic matter in the bottom material. This hyopthesis is based on a three-year study of diffusive flux in the...
A macrophyte submodel for aquatic ecosystems
Carol Desormeau Collins, Joseph H. Wlosinski
1989, Aquatic Botany (33) 191-206
A macrophyte submodel has been incorporated and tested in CE-QUAL-R1, a one-dimensional, vertically averaged model of reservoir water quality. A quasi two-dimensional scheme was necessary to represent the spatial relationship of macrophytes in reservoirs adequately. The macrophyte processes modeled were photosynthesis, dark respiration, excretion and nonpredatory mortality. Process equations for...
Distribution, habitat, and future of Harter's water snake, Nerodia harteri, in Texas
N.J. Scott Jr., T.C. Maxwell, O.W. Thornton Jr., L.A. Fitzgerald, J.W. Flury
1989, Journal of Herpetology (23) 373-389
Detailed studies of the distribution and habitat use of the endemic Texas snake Nerodia harteri were conducted from 1979 to 1987. The Brazos water snake N. h. harteri is restricted to the upper Brazos River drainage; it is found in about 303 km of stream plus two reservoirs, Possum Kingdom...
Observed parameters for turbidity-current flow in channels, Reserve Fan, Lake Superior
W. R. Normark
1989, Journal of Sedimentary Petrology (59) 423-431
Fine-grained tailings discharged from a taconite-ore processing operation near the shore of Lake Superior produced turbidity currents that transported the sediment from a small delta into deep water at Silver Bay, Minnesota. Deposition over nearly 20 years produced a sublacustrine fan with two...
Comparison of seismic waveform inversion results for the rupture history of a finite fault: Application to the 1986 North Palm Springs, California, earthquake
S. Hartzell
1989, Journal of Geophysical Research Solid Earth (94) 7515-7534
The July 8, 1986, North Palm Springs earthquake is used as a basis for comparison of several different approaches to the solution for the rupture history of a finite fault. The inversion of different waveform data is considered; both teleseismic P waveforms and local strong ground motion records. Linear parametrizations for slip...
Viking landing sites, remote-sensing observations, and physical properties of Martian surface materials
H. J. Moore, B. M. Jakosky
1989, Icarus (81) 164-184
Important problems that confront future scientific exploration of Mars include the physical properties of Martian surface materials and the geologic processes that formed the materials. The design of landing spacecraft, roving vehicles, and sampling devices and the selection of landing sites, vehicle traverses, and sample sites will be, in part,...
The role of catastrophic geomorphic events in central Appalachian landscape evolution
R. B. Jacobson, A.J. Miller, J. A. Smith
1989, Geomorphology (2) 257-284
Catastrophic geomorphic events are taken as those that are large, sudden, and rare on human timescales. In the nonglaciated, low-seismicity central Appalachians, these are dominantly floods and landslides. Evaluation of the role of catastrophic events in landscape evolution includes assessment of...
Petrology of the zoned calcalkaline magma chamber of Mount Mazama, Crater Lake, Oregon
T. H. Druitt, C. R. Bacon
1989, Contributions to Mineralogy and Petrology (101) 245-259
Evolution of the magma chamber at Mount Mazama involved repeated recharge by two types of andesite (high-Sr and low-Sr), crystal fractionation, crystal accumulation, assimilation, and magma mixing (Bacon and Druitt 1988). This paper addresses the modal compositions, textures, mineral chemistry and magmatic temperatures of (i) products of the 6845±50 BP...
The competition between thermal contraction and differentiation in the stress history of the Moon
Randolph L. Kirk, David J. Stevenson
1989, Journal of Geophysical Research B: Solid Earth (94) 12133-12144
The scarcity of both extension and compression features on the Moon strongly constrains the history of the lunar radius—to variations of less than ±1 km over the past 3.8 Gyr. This limit has traditionally been interpreted as requiring a delicate balance between thermal contraction of the near‐surface and expansion of...
Style of extensional tectonism during rifting, Red Sea and Gulf of Aden
R. G. Bohannon
1989, Journal of African Earth Sciences (8) 589-602
Models describing the development of the Red Sea and the Gulf of Aden, prior to the present periods of sea-floor spreading, include those that use block faulting on steep normal faults, uniform diffuse shear in continental crust, simple shear on large detachment faults that cut the entire lithosphere, combinations involving...
Statistical analysis of factors affecting landslide distribution in the new Madrid seismic zone, Tennessee and Kentucky
R.W. Jibson, D. K. Keefer
1989, Engineering Geology (27) 509-542
More than 220 large landslides along the bluffs bordering the Mississippi alluvial plain between Cairo, Ill., and Memphis, Tenn., are analyzed by discriminant analysis and multiple linear regression to determine the relative effects of slope height and steepness, stratigraphic variation, slope aspect, and proximity to the hypocenters of the 1811-12...
Chemical composition of maturing and spawning Atlantic salmon from different locations
H. A. Poston, H. G. Ketola
1989, Progressive Fish-Culturist (51) 133-139
We examined the relation between the environmental or nutritional background and the chemical composition of body tissues and reproductive success in wild (sea‐run, river‐captured, ocean‐captured, landlocked) and hatchery‐reared Atlantic salmon (Salmo salar). More essential fatty acids of the linolenic acid family (n‐3 acids, also called ω‐3 acids) occurred in eggs...
Predicting earthquakes by analyzing accelerating precursory seismic activity
D. J. Varnes
1989, Pure and Applied Geophysics PAGEOPH (130) 661-686
During 11 sequences of earthquakes that in retrospect can be classed as foreshocks, the accelerating rate at which seismic moment is released follows, at least in part, a simple equation. This equation (1) is {Mathematical expression},where {Mathematical expression} is the cumulative sum until time, t, of the square roots of...
Influence of Shimada Seamount on sediment composition in the eastern tropical North Pacific
W.E. Dean, J.V. Gardner, L P. Nancy
1989, Geochimica et Cosmochimica Acta (53) 1523-1536
Shimada Seamount is a large, young volcanic edifice in the east-central Pacific that is not associated with any active spreading center or known hot spot. The sediments on the abyssal plain surrounding Shimada Seamount consist of pelagic clay with ferromanganese micronodules and zeolites. The pelagic clay is mostly barren of...
Active faulting and deformation of the Coalinga anticline as interpreted from three-dimensional velocity structure and seismicity
D. Eberhart-Phillips
1989, Journal of Geophysical Research Solid Earth (94) 15565-15586
This work gives a clear picture of the geometry of aftershock seismicity in a large thrust earthquake. Interpretation of hypocenters and fault plane solutions, from the 1983 Coalinga, Coast Range California, earthquake sequence, in combination with the three-dimensional velocity structure shows that the active faulting beneath the fold primarily consists...
A high-density remote reference magnetic variation profile in the Pacific northwest of North America
J.F. Hermance, S. Lusi, W. Slocum, G.A. Neumann, A.W. Green Jr.
1989, Physics of the Earth and Planetary Interiors (53) 305-319
During the summer of 1985, as part of the EMSLAB Project, Brown University conducted a detailed magnetic variation study of the Oregon Coast Range and Cascades volcanic system along an E-W profile in central Oregon. Comprised of a sequence of 75 remote reference magnetic variation (MV) stations spaced 3-4 km...
Depositional history of the Lagniappe Delta, northern Gulf of Mexico
J. L. Kindinger
1989, Geo-Marine Letters (9) 59-66
The northern Gulf of Mexico continental shelf is characterized by superimposing deltas. One such delta, informally named Lagniappe, extends east of the Mississippi Delta from mid-shelf to the continental slope. This late Wisconsinan delta is adjacent to, but not associated with the Mississippi Delta complex: the fluvial source was probably...
Diapiric transfer of melt in Kilauea Iki lava lake, Hawaii: A quick, efficient process of igneous differentiation
Rosalind Tuthill Helz, H. Kirschenbaum, J.W. Marinenko
1989, Geological Society of America Bulletin (101) 578-594
Kilauea Iki lava lake, formed in 1959, is a large pond of picritic basalt (average MgO content = 15.34% by weight), which has cooled and crystallized as a small, self-roofed magma chamber. Repeated drilling of the upper crust of the lake, down to its molten core, and more recent (1981)...
Preliminary evaluations of regional ground-water quality in relation to land use
D. Cain, D.R. Helsel, S.E. Ragone
1989, Ground Water (27) 230-244
Preliminary results from New York, New Jersey, Connecticut, Florida, Nebraska, and Colorado indicate that regional ground-water quality has been affected by human activities. The frequencies of detection of volatile organic compounds and some trace elements were larger in ground water underlying urban or industrial areas in comparison to undeveloped areas....
