Possible role of lysosomes in the detoxication of copper in the digestive gland cells of metal-exposed mussels     

A. Viarengo  M. Pertica  G. Mancinelli  M. Orunesu  G. Zanicchi  M.N. Moore  R.K. Pipe 《Marine environmental research》1984,14(1-4)

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Implications of solar flare dynamics for reconnection in magnetospheric substorms     

R.L. Moore  J.L. Horwitz  J.L. Green 《Planetary and Space Science》1984,32(11):1439-1454

From observations of two-ribbon solar flares, we present a new line of evidence that magnetic reconnection is of key importance in magnetospheric substorms. We infer that in substorms reconnection of closed field lines in the near-Earth thinned plasma sheet both initiates and is driven by the overall MHD instability that drives the tailward expulsion of the reconnected closed field (0 loops). The general basis for this inference is the longstanding notion that two-ribbon flares and substorms are essentially similar phenomena, driven by similar processes. We give an array of observed similarities that substantiate this view. More specifically, our inference for substorms is drawn from observations of filament eruptions in two-ribbon flares, from which we conclude that the heart of the overall instability consists of reconnection and eruption of the closed magnetic field in and around the filament. We propose that essentially the same overall instability operates in substorms. Our point is not that the magnetic field configuration or the microphysics in substorms is identical to that in two-ribbon flares, but that the overall instability results from essentially the same combination of reconnection and eruption of closed magnetic field.  相似文献   

Thorium and radium isotopic relationships in manganese nodules and sediments at MANOP Site S     

Willard S Moore 《Geochimica et cosmochimica acta》1984,48(5):987-992

Relationships among Th and Ra isotopes in nodule, sediment and water phases at MANOP Site S establish the most likely source for Th in the nodules, the frequency of nodule turning, and the similarity of micro and macro nodules. Manganese nodules and bottom waters have ${}^{230}\text{Th}{}^{232}\text{Th}$ activity ratios considerably higher than other phases at this site suggesting that sea water is the likely source of Th for the nodules. Similar ${}^{230}\text{Th}{}^{232}\text{Th}$ activity ratios in nodule tops and bottoms and in certain cases departure from expected ${}^{226}\text{Ra}{}^{230}\text{Th}$ activity ratios in nodule tops and bottoms indicate that the nodules rotate every one to ten thousand years. The micro nodules have diffusion coefficients of Ra similar to macro nodule bottoms. I suggest that they may act as a carrier phase for transporting metals through oxic sediments to nodules.  相似文献   

Geochemical indicators of a high-temperature geothermal system     

J.N. Moore  R.M. Capuano  O.D. Christensen 《Journal of Geochemical Exploration》1983,19(1-3)

The intensity and distribution of hydrothermal alteration are frequently used during the exploration and assessment of a geothermal prospect to estimate the size, shape and temperature of a thermal system. Geochemical and petrographic observations used to characterize the hydrothermal alteration include the mapping of both trace- and major-element dispersion patterns and the distribution of secondary mineral assemblages.This paper describes the trace-element and mineralogical distributions common to many of the high-temperature systems (> 150°C) that we have studied. However, examples of important geochemical relationships are primarily drawn from our detailed investigations of the Roosevelt Hot Springs thermal system in southern Utah. The hydrothermal fluids at Roosevelt Hot Springs are enriched in sodium chloride and contain approximately 9000 ppm total dissolved solids. The reservoir, with a base temperature near 270°C, is located in fractured gneisses and granites.At Roosevelt Hot Springs, the surface discharges consist of opaline and chalcedonic sinter, and alluvium cemented by silica, calcite, Mn oxide and Fe oxide. The geochemistry of these surface deposits is extremely variable, but locally they contain up to 5.5 ppm Hg, 858 ppm As, 18.8% Mn, 230 ppm Cu, 290 ppm Sb, 294 ppm W, 17 ppm Li, 68 ppm Pb, 26 ppm Zn, 4.9% Ba and 100 ppm Be. High concentrations of Au and Ag, although not present in the sinters at Roosevelt Hot Springs, occur in hot spring deposits from other chemically similar systems such as Steamboat Springs, Nevada.Mercury and As are the most widely distributed trace elements in the surface samples. Their distribution in soils overlying the thermal system expands the area of interest and helps define the high-temperature portion of the system. The highest concentrations of Hg and As, of up to 5.5 and 26 ppm, respectively, occur in soils within 300 m of the thermal discharges. A broader area extending up to 1000 m from the surficial thermal activity also contains ppb. Mercury anomalies tend to mark the location of faults within the uppermost portions of the reservoir and areas where the thermal fluids move laterally away from the thermal system toward the adjacent valley.Depletions of Mn, Cu and Zn are found in the acid-altered soils and in alluvium associated with the hot spring deposits and fumaroles. The acid alteration occurs locally in areas of surficial thermal activity and persists to depths of less than 60 m. Alteration minerals within these zones include alunite, jarosite, native sulphur, opal, chalcedony, kaolinite, sericite, montmorillonite, and mixed-layer clays. The formation of acid waters occurs near the surface and results from the oxidation of H₂S contained within gases evolving from the fumaroles or within waters discharged by the hot springs. The locally intense acid-sulphate alteration and scavenging of metals within the soils occurs as the fluids percolate downward.Alteration mineralogy at depth is determined through examination of down-hole samples which penetrate the geothermal system to depths in excess of 2 km. Reservoir rocks of temperatures below about 210°C contain an alteration assemblage with mixed-layer clays, montmorillonite, sericite, pyrite, hematite, magnetite, calcite, chlorite, quartz, and potassium feldspar. At higher temperatures, mixed-layer clays and montmorillonite disappear and anhydrite appears locally.Altered rocks within the high temperature portions of the thermal field are characterized by anomalous concentrations of As and Li. Selective chemical leaching of the altered rocks and electron microprobe analyses indicate that As is contained primarily in pyrite or iron oxides after pyrite whereas Li occurs in clays and micas.Mercury exhibits an inverse relationship with temperature and is concentrated in the cooler portions of the thermal system to depths marked approximately by the 200°C isotherm. This distribution is similar to the distribution of clay minerals in the reservoir rock. Heating experiments indicate that Hg occurs primarily as Hg° and that it is readily mobilized by the thermal system at temperatures in excess of 200–250°C.  相似文献   

Crystal structure of steenstrupine: A rod structure of unusual complexity     

Dr. P. B. Moore  Dr. J. Shen 《Mineralogy and Petrology》1983,31(1-2):47-67

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Ground failure around buried tubes     

I. D. Moore  J. R. Booker 《Rock Mechanics and Rock Engineering》1987,20(4):243-260

Summary The hoop forces which develop in circular tubes buried in elastic-plastic ground are investigated. A closed form solution is used to determine the hoop forces which develop when the field stresses in the elastic-plastic ground are initially uniform. The finite element method is used to solve the problem for biaxial field stress. A parametric study is undertaken to assess the influence of tube stiffness and ground strength on the hoop forces, and use is made of elastic stress contours to predict the likely extent of material failure around tubes buried in ground with biaxial prestress.Notation a tube radius - c cohesion - D flexural stiffness of the structure - E _i Young's modulus of structure - E _s Young's modulus of ground - F hoop force (compression positive) - G _s shear modulus of ground - H hoop stiffness of the structure - K coefficient of lateral pressure - N tan²(45+/2) - q ( ₁– ₁)/2 - S _f relative flexural stiffness of the structure - S _h relative hoop stiffness of the structure - t structural thickness - v circumferential displacement - w radial displacement - v _l Poisson's ratio of structure - v _s Poisson's ratio of ground - normal traction acting on the structure - _d deviatoric component of field stress - _h horizontal field stress - _m uniform component of field stress - _v vertical field stress - ₁ major principal stress - ₃ minor principal stress - tangential traction acting on the structure - angle of internal friction of the ground - angle of dilation of the ground  相似文献   

Geochemistry of barium in pelagic sediments     

K. Boström  O. Joensuu  C. Moore  B. Boström  M. Dalziel  A. Horowitz 《Lithos》1973,6(2):159-174

High concentrations and accumulation rates of Ba occur on active (spreading) ridges, and in some areas of high biological productivity. These patterns show that Ba is deposited on the deep sea floor by both volcanic and biological processes.  相似文献   

An estimate of the juvenile sulfur content of basalt     

James G. Moore  Brent P. Fabbi 《Contributions to Mineralogy and Petrology》1971,33(2):118-127

Sulfur analyses by X-ray fluorescence give an average content of 107 ppm for 9 samples of fresh subaerially-erupted oceanic basalt and 680 ppm for 38 samples of submarine erupted basalt. This difference is the result of retention of sulfur in basalt quenched on the sea floor and loss of sulfur in basalt by degassing at the surface. The outer glassy part of submarine erupted basalt contains 800±150 ppm sulfur, and this amount is regarded as an estimate of the juvenile sulfur content of the basalt melt from the mantle. The slower cooled interiors of basalt pillows are depleted relative to the rims owing to degassing and escape through surface fractures. Available samples of deep-sea basalts do not indicate a difference in original sulfur content between low-K tholeiite, Hawaiian tholeiite, and alkali basalt.The H₂O/S ratio of analyzed volcanic gases is generally lower than the H₂O/S ratio of gases presumed lost from surface lavas as determined by chemical differences between pillow rims and surface lavas. This enrichment of volcanic gases in sulfur relative to water may result from a greater degassing of sulfur relative to water from shallow intrusive bodies beneath the volcano.Publication authorized by the Director, U.S. Geological Survey.  相似文献   

Carbon and its isotopes in mid-oceanic basaltic glasses     

David J. Des Marais  James G. Moore 《Earth and Planetary Science Letters》1984,69(1):43-57

Three carbon components are evident in eleven analyzed mid-oceanic basalts: carbon on sample surfaces (resembling adsorbed gases, organic matter, or other non-magmatic carbon species acquired by the glasses subsequent to their eruption), mantle carbon dioxide in vesicles, and mantle carbon dissolved in the glasses. The combustion technique employed recovered only reduced sulfur, all of which appears to be indigenous to the glasses. The dissolved carbon concentration (measured in vesicle-free glass) increases with the eruption depth of the spreading ridge, and is consistent with earlier data which show that magma carbon solubility increases with pressure. The total glass carbon content (dissolved plus vesicular carbon) may be controlled by the depth of the shallowest ridge magma chamber. Carbon isotopic fractionation accompanies magma degassing; vesicle CO₂ is about 3.8‰ enriched in ¹³C, relative to dissolved carbon. Despite this fractionation, δ¹³C_PDB values for all spreading ridge glasses lie within the range ?5.6 and ?7.5, and the δ¹³C_PDB of mantle carbon likely lies between ?5 and ?7. The carbon abundances and δ¹³C_PDB values of Kilauea East Rift glasses apparently are influenced by the differentiation and movement of magma within that Hawaiian volcano. Using ³He and carbon data for submarine hydrothermal fluids, the present-day mid-oceanic ridge mantle carbon flux is estimated very roughly to be about 1.0 × 10¹³ g C/yr. Such a flux requires 8 Gyr to accumulate the earth's present crustal carbon inventory.  相似文献   

A switched continuous-wave sonic anemometer for measuring surface heat fluxes     

W. J. Shuttleworth  D. D. McNeil  C. J. Moore 《Boundary-Layer Meteorology》1982,23(4):425-448

A one-dimensional sonic anemometer system suitable for use in measuring near surface heat fluxes is described. It operates by transferring continuous sound waves in alternate directions between a matched pair of cheap ultrasonic transducers. The design and development of the anemometer is described, together with wind tunnel tests, and field experiments, in which the performances of several prototypes are compared with those of other anemometers over stubble and over forest. The results indicate that the device is suitable for measuring eddy correlation heat fluxes to an accuracy better than 5%.  相似文献