Sediment yield estimated from reservoir siltation in the Ochil hills,Scotland

Measurements made on the floors of the temporarily-drained Glenfarg and Glenquey Reservoirs indicate that sediments with wet volumes of 63.94 × 10³ m³ and 12.64 × 10³ m³ were deposited in 56 and 73 years respectively. These figures represent 2.5 per cent and 1.1 per cent losses of original storage capacity. When corrected for water, organic, and diatom skeleton contents, and reservoir trap efficiency inorganic sediment yields of at least 31.3 tonnes km^?2 yr^?1 and of 9.0 tonnes km^?2 yr^?1 are suggested. The difference is probably related to contrasts of land use.     

Macrophyte detritus in the winter diet of the estuarine mysid,Neomysis americana

Neomysis americana, a common prey item in the diet of estuarine fish, is seasonally abundant in saltmarsh tidal creeks of North Inlet, South Carolina. Visual examination of mysids collected in winter revealed only diatom tests in their guts, with nearly all of the ingesta unidentifiable. Immunological diet analysis provided strong evidence that proteins fromSpartina alterniflora detritus were present in the guts of field-collected mysids. Laboratory determinations of weight-specific ingestion rates for male and female mysids fed particulateS. alterniflora were best described by a curvilinear quadratic function. Ingestion rates ranged from zero to 0.116 mg C ingested per mg C body weight per hr, or greater than 200% of body carbon per day if continuous feeding is assumed. These high ingestion rates may indicate low assimilation efficiency, but ifN. americana’s assimilation efficiency is similar to that of other mysid species, then this mysid may represent an efficient trophic link between saltmarsh macrophyte production and higher trophic levels. The occurrence ofSpartina detritus in the guts of winter mysids suggests that detritivory may be important during periods of scarce food.     

Preferential leaching and the age of radiation damage from alpha decay in minerals

Preferential release into solution of radionuclides that result from alpha decay is a contributor to natural isotopic disequilibrium. Such release is critical to geochemical understanding of alpha-decay products and would be an undesirable characteristic of solidified nuclear waste in deep geological formations. Spontaneous annealing of the radiation damage that is responsible for the preferential release is shown to diminish the effect in thorianite and uraninite which we have found to be 550 to 1000 M.y. old, respectively. Leaching experiments and measurements of the thorium and uranium isotopes show that there is strongly enhanced release of short-lived ²²⁸Th relative to ²³²Th, but only slight enhancement of long-lived ²³⁴U and ²³⁰Th relative to ²³⁸U and ²³²Th. These results are interpreted in terms of natural annealing of damage occurring on a time scale between the ~10 and 10⁵ years of the alpha-decay products. With a simple assumption actual times for the survival of the enhanced leaching in these minerals are ~ 15,000 years.     

Copper(II) carbonate complexation in seawater

Cupric carbonate and cupric bicarbonate complexation constants were determined in natural seawater and in a variety of synthetic media. The formation constants of CuHCO₃⁺, CuCO₃⁰ and Cu(CO₃)₂^2? at 25°C and zero ionic strength are: log β_H⁰ = 1.8, log β₁⁰ = 6.82 and log β⁰₂ = 10.6. Formation constants of these species appropriate to 0.7 molar ionic strength and 25°C are log β_H ～- 1, log β₁ = 5.73, log β₂ = 9.3. Our results indicate that the inorganic speciation scheme of Cu(II) in seawater is dominated by CuCO₃⁰ and that the ternary species, CuCO₃OH^?, is of substantial importance.     

Association of subsurface radon changes in Alaska and the northeastern United States with earthquakes

Changes of radon concentration in the ground have been reported to correlate with seismic activity in many places over widely varying distances from the earthquake epicenters, sometimes over 100's and occasionally over 1000's of km depending on the magnitude M of the earthquakes. For proper use of such correlations in forecasting the location and size of impending earthquakes, it would be useful to establish a relation between M and the maximum distance x_M at which radon can be significantly altered by preseismic effects.We have monitored radon in the ground continuously at Blue Mountain Lake, NY starting Dec. 3. 1975 and at three locations in Alaska—Icy Bay, Yakataga, and Sand Point (starting Nov. 12, 1979; March 5, 1980; and June 29, 1980 respectively). Sample correlations from visual examination of the recent radon record and tentative use of a proposed scaling relation show a number of possible earthquake-related signals at these locations. The data are compatible with scaling relations that were derived from two separate models of premonitory elastic strains. In this work x_M = 10^0.48M, where x_M is in units of km and M ≥ 3. Since tilt and strain signals correlate similarly with magnitude and distance, it is likely that most earthquake-related radon signals are mechanically induced.     

Microtectonic evidence for eastward ductile shear in the Jurassic orogen of SW Japan

Two Jurassic deformation phases are responsible for the thrust and nappe structures in the infrastructure of the outer belt of the Mesozoic chain of SW Japan. The first phase was synmetamorphic, and took place under HP/LT conditions. Microtectonic analysis shows that the penetrative deformation corresponded to a ductile shear directed from W to E, parallel to the stretching and mineral lineation. At the regional scale the first phase corresponded to the obduction of the Greenschist nappes upon the Kurosegawa continent. During the second phase the Greenschist nappes were sliced, leading to an apparent reverse metamorphic zoning. The first phase structures were then locally reworked by folds giving rise to an apparent westwards sense of shear.     

Solution chemistry studies and flotation behaviour of apatite,calcite and fluorite minerals with sodium oleate collector

The maximum flotation response for three naturally occurring calcium minerals, apatite, calcite and fluorite with sodium oleate collector correlated directly with the minimum interfacial tension of the air/solution interface. For fluorite and apatite the minimum surface tension occurred about the mid-pH region and was attributed to the formation of pre-micellar associated species in solution. In the case of calcite the minimum was observed at high pH since the presence of high concentrations of calcium ions in solution appeared to reduce the concentration of amphililic species in the low and mid-pH regions.Microelectrophoresis data demonstrated that the three minerals acquired a negative charge in sodium oleate solution, resulting from adsorption of oleate species on the mineral surfaces.The flotation behaviour of the systems were shown to be related to the species distribution diagrams suggesting that the role of the acid soap dimer, soap dimer, molecular and lattice species could make a significant contribution to the character and composition of the interfacial films.High flotation response was explained by strong adhesion between the hydrophobic particle and bubble. It was suggested that the reduction in surface tension may not be the major factor contributing to the flotation efficiency but indicated the presence of associated surfactant species in solution which could also synergistically adsorb at the solid/liquid interface, increasing the hydrophobic character of the mineral surface. This would maximize the magnitude of the contact angle and hence the strength of the adhesion between particle and bubble. This adsorption behaviour is not in general agreement with conventionally non-hydrolyzable collector theory which is usually based on electrostatic models.     

Distribution of forms of sulfur in peats from saline environments in the Florida Everglades

Although there is published information on the mechanism of sedimentary pyrite formation resulting from bacterial reduction of sulfate, little is known about the distribution of forms of sulfur, including organic, in peats. In order to increase understanding of the geochemistry of sulfur in coals, we have determined distributions of forms of sulfur in five cores of saline peat and one of brackish peat, all from areas near the Shark River and Whitewater Bay in the coastal swamps of south Florida. All concentrations vary widely with depth. Total sulfur concentrations range up to 6% of dry solids. Minor amounts of sulfur are present as H₂S, S⁰, SO₄²⁻, and acid-soluble sulfide, but the principal forms are usually pyritic and organic. The ratio, organic/pyritic, is highly variable, but at a majority of levels in a profile is considerably greater than unity. It is inferred that topochemical factors are important in determining the distribution of sulfur forms in any element of volume.     

Observation pétrographique d'un cas de mélange de magmas acide et basique: genèse des dacitoïdes de la région de Qom-Aran (Iran central)

Résumé Dans les pyroclastites de l'Eocène supérieur de la région de Qom-Aran (Iran Central) existent des roches à aspect intermédiaire entre des laves et des roches pyroclastiques (laves bréchiques).Ces laves hétérogénes présentent deux composants originaux: l'un acide formant la matrice claire (rhyolite à structure fluidale), l'autre basique, sombre, vitreux, en forme de micropillows et/ou de flammes.L'étude détaillée des contacts entre ces deux composants, illustrée par une série de microphotographies, implique l'état liquide des deux composants lors de leur mélange. L'homogénéisation mécanique aboutit à des laves intermédiaires (dacitoïdes). Durant ce dernier processus, des phénomènes de diffusion entre les deux magmas contrastés provoquent certains changements chimiques dans la composition originelle de chacun des deux composants.

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Petrographic Observations on Mixing of Acid and Basic Magmas: Genesis of the Dacitoïdes of the Qom-Aran Area (Central Iran)Among the Upper Eocene pyroclastic materials of the Qom-Aran area (Central Iran) there are rocks (named lava-breccias) with intermediate facies between lavas and pyroclastic rocks.These heterogeneous lavas exhibit two distinct components: (1) an acid one, making up the light-coloured groundmass (fluidal rhyolite), and (2) a basic, dark, vitreous component in the shape of micro-pillows and/or flame-like patches.A detailed study of the boundaries between these two components has been performed and illustrated by several microphotographs. It shows that the two components were in a liquid state when mixed with each other. Mechanical homogeneization results into an intermediate lava (dacitoïde). During this process, diffusion phenomena between the two contrasted magmas brought about chemical changes in the original composition of each — basic and acid — component.