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A nearshore-bar system was surveyed periodically through a storm and the following recovery period. The data showed a very rapid response of morphology to changing wave conditions and allowed various models on bar formation to be tested.Under low-energy conditions prior to the storm a small bar was surveyed 13 m...

A phenomenological constitutive equation can serve as a basis for modeling and classifying mass-movement processes. The equation is derived using the principles of continuum mechanics and several simplifying assumptions about mass-movement behavior. These assumptions represent idealizations of field behavior, but they appear...

The annual formation of otolith annuli was validated through age 5 for Florida largemouth bass Micropterus salmoides floridanus. Sectioned otoliths (sagittae) gave more reliable ages than whole otoliths. Beginning at age 2, at least one annulus was obscure in some whole‐otolith mounts, a problem that worsened with fish age. By...

Generation of transgressive barrier island arcs along the Mississippi River delta plain and preservation of barrier shoreline facies in their retreat paths on the inner shelf is controlled by: (1) shoreface translation; (2) age of the transgression; and (3) the thickness of the barrier island arc sediment package. Barrier island...

Most deep-sea sediments contain one or more biogenic components and one dominant nonbiogenic component, usually clay or silty clay. The authors present a descriptive classification scheme in which deep-sea, fine-grained sediments are placed within a three-components system of calcareous-biogenic, siliceous-biogenic, and nonbiogenic components. In a three-procedure the user assesses whether...

Long-term studies were used to examine (1) contrasting time scales and mechanisms of structural variations within two benthic communities and (2) the usefulness of long data sets for evaluating human impact. A 10-year study of a San Francisco Bay mudflat, the details of which are reported elsewhere, has revealed large...

The benthic invertebrate community inhabiting the extensive and sedimentologically homogeneous mudflats of South San Francisco Bay has demonstrated a high degree of constancy in both species composition and relative abundance among species throughout 10 yr of observation. The community, composed predominantly of introduced species with opportunistic lifestyles, is dominated numerically...

We carried out an extensive paleointensity study of the 15.5±0.3 m.y. Miocene reversed‐to‐normal polarity transition recorded in lava flows from Steens Mountain (south central Oregon). One hundred eighty‐five samples from the collection whose paleodirectional study is reported by Mankinen et al. (this issue) were chosen for paleointensity investigations because of...

The thick sequence of Miocene lava flows exposed on Steens Mountain in southeastern Oregon is well known for containing a detailed record of a reversed‐to‐normal geomagnetic polarity transition. Paleomagnetic samples were obtained from the sequence for a combined study of the directional and intensity variations recorded; the paleointensity study is...

Although the United States is the world's largest producer and exporter of phosphates, serious doubts have arisen in recent years that U. S. deposits could sustain this important role. The development of borehole mining; i. e. , extracting the phosphate matrix as a slurry through a drill hole, however, is...

Forty-five sets of separate, normal twins were produced from four portions of the eggs from one female sea lamprey (Petromyzon marinus) each fertilized by a different male. The percentage of twinning in the different groups of embryos ranged from 1.0 to...

Ninety-two West Indian manatees (Trichechus manatus) have been captured in the southeastern United States from October 1975 through November 1983 with no evidence of an unusual susceptibility to capture myopathy. Of these, 53 were radio-tracked or observed in the field following capture with no evidence of delayed capture stress. Blood samples obtained...

Under the assumption that landforms unaffected by drainage channels are degraded according to the linear diffusion equation, a procedure is developed to invert a scarp profile to find its “diffusion age.” Diffusion age, having dimension [length]2, is the product of diffusivity times chronological age. The second moment of scarp slope...

Experiments were conducted to measure the agglutinating antibody response of channel catfish to a particulate and a soluble antigen administered simultaneously by one of three routes. Specific antibody production in response to administration of particulate brucella tube-test antigen via intramuscular injection, oral drench, and topical application peaked at 3 weeks...

Extensive low-lying marine deposits border the southeastern United States Atlantic Coastal Plain. Some units are fossiliferous and contain corals as isolated fragments in sediments of a detrital character. These corals are subject to alteration processes such that suites of related samples must be...

The instantaneous unit Hydrograph (IUH) of a drainage basin is derived in terms of fundamental basin characteristics (Z, α, β), where α parameterizes the link (channel segment) length distribution, and β is a vector of hydraulic parameters, Z is one of three basin topological properties, N, (N, D), or (N, M), where N is magnitude (number of...

A SAS program is presented which constructs a composite section of stratigraphic events through principal components analysis. The variables in the analysis are stratigraphic sections and the observational units are range limits of taxa. The program standardizes data in each section, extracts eigenvectors, estimates missing range limits, and computes the...

The hydrochemistry of Great Salt Lake, Utah, has been defined for the historic period, 1850 through 1982, from published data combined with new observations. The water balance depends largely on river inflow, atmospheric precipitation onto the lake surface and evaporation. Input of the major solutes can best be accounted for...

Late Eocene-early Oligocene (42-35 Myr) sediments cored at two DSDP sites in the south-west Pacific contain evidence of a pronounced increase in local volcanic activity, particularly in close association with the Eocene-Oligocene boundary. This pulse of volcanism is coeval with that in New Zealand and resulted from the development of...

Nearly two decades of seasonal dissolved inorganic nutrient-salinity distributions in northern San Francisco Bay estuary (1960-1980) illustrate interannual variations in effects of river flow (a nutrient source) and phytoplankton productivity (a nutrient sink). During winter, nutrient sources dominate the nutrient-salinity distribution patterns (nutrients are at or exceed conservative mixing concentrations)....

Major element, trace element and Sm-Nd isotope analyses were made of polymetamorphic hornblendefelses, plagioclase amphibolites and banded amphibolites from the Berisal complex in the Simplon area (Italy, Switzerland) to determine their age, origin and genetic relationships. In light of major and rare earth element data, the hornblendefelses are inferred to...

The distributions of earthquakes and late Cenozoic and Quaternary volcanism in Washington and northern Oregon change markedly across two northeast-striking lines, one near Mount Rainier and one near Mount Hood. On the basis of these observations and a comparison with the Nazca subduction zone, we propose...

With the maturation of oil and gas production operations in a province or country, fields found by new-field wildcats diminish in size. The actual economic size cutoff is a function of such factors as depth, water depth offshore, and accessibility to transportation infrastructure. Because of the constraint of resource availability,...

Government engineers often are not required to be registered in the state in which they practice, even though their counterparts in the private sector must be registered. Government engineers have a responsibility to safeguard the public health and safety, and must develop in the public a sense of confidence that...

Little consensus exists on how best to analyze natural fracture spacings and their sequences. Field measurements and analyses published in geotechnical literature imply fracture processes radically different from those assumed by theoretical structural geologists. The approach adopted in this paper recognizes that disruption of rock layers by layer-parallel extension results...