Volatiles H2O,CO2, and Cl in a subduction related basalt     

David M. Harris  Alfred T. Anderson Jr. 《Contributions to Mineralogy and Petrology》1984,87(2):120-128

The products of the 1974 eruption of Fuego, a subduction zone volcano in Guatemala, have been investigated through study of silicate melt inclusions in olivine. The melt inclusions sampled liquids in regions where olivine, plagioclase, magnetite, and augite were precipitating. Comparisons of the erupted ash, groundmass, and melt inclusion compositions suggest that the inclusions represent samples of liquids present in a thermal boundary layer of the magma body. The concentrations of H₂O and CO₂ in glass inclusions were determined by a vacuum fusion manometric technique using individual olivine crystals (Fo77 to Fo71) with glass inclusion compositions that ranged from high-alumina basalt to basaltic andesite. Water, Cl, and K₂O concentrations increased by a factor of two as the olivine crystals became more iron-rich (Fo77 to Fo71) and as the glass inclusions increased in SiO₂ from 51 to 54 wt.% SiO₂. The concentration of H₂O in the melt increased from 1.6 wt.% in the least differentiated liquid to about 3.5% in a more differentiated liquid. Carbon dioxide is about an order of magnitude less abundant than H₂O in these inclusions. The gas saturation pressures for pure H₂O in equilibrium with the melt inclusions, which were calculated from the glass inclusion compositions using the solubility model of Burnham (1979), are given approximately by P(H₂O)(Pa)=(SiO₂−48.5 wt.%) × 1.45 × 10⁷. The concentrations of water in the melt and the gas saturation pressures increased from about 1.5% to 3.5% and from 300 to 850 bars, respectively, during pre-eruption crystallization.  相似文献   

Initial volatilization temperatures and average volatilization rates of coal — Their relationship to coal rank and other characteristics     

O.C. Kopp  L.A. Harris 《International Journal of Coal Geology》1984,3(4):333-348

Two thermal parameters, initial volatilization temperature (IVT) and average volatilization rate (AVR), have been determined by thermogravimetric analysis in argon for 38 coal samples ranging in rank from lignite to low-volatile bituminous. Both IVT and AVR are correlated with percent volatile matter and vitrinite reflectance.The IVT values increase gradually from about 250 to 445°C with increasing rank; however, a change in slope is observed in the region of high-volatile bituminous coals (from about 340°C to about 380°C) when IVT's are plotted against percent volatile matter or percent fixed carbon. The changes in slope near 340°C and near 380°C occur at “coalification jumps” recognized on the basis of changes in the optical and chemical character of the macerals. In general, AVR values decrease gradually with increasing rank for the lignite and sub-bituminous coals and for the medium- and low-volatile bituminous coals; however, a sharp increase in AVR occurs in high-volatile bituminous coals. The change in slope of the IVT curves and sharp increase in the AVR values for high-volatile bituminous coals reflect the development of new, higher vapor pressure organic compounds produced during this stage of the coalification process.A plot of AVR vs IVT reveals three regions which correspond to: (1) lignite and sub-bituminous coals; (2) high-volatile bituminous coals; and (3) medium- to low-volatile bituminous coals.  相似文献   

Temporal and spatial variations of marine aerosols over the Atlantic Ocean     

F.P. Parungo  C.T. Nagamoto  J.M. Harris 《Atmospheric Research》1986,20(1)

Aerosol samples, collected daily were analyzed with electron microscopy for particle concentration and size distribution. The chemical compositions of individual particles were determined with X-ray energy spectrometry and specific morphological tests. The results demonstrated clear and significant dependencies of aerosol properties on air trajectories computed from a backtrack model. Air parcels, such as American air pollution and Sahara dust, were identified. Their physical mixing and chemical reactions with marine aerosols as well as aerosol wet deposition are discussed.  相似文献   

Earthquake simulator testing of pounding between adjacent buildings     

Manolis Papadrakakis  Harris P. Mouzakis 《地震工程与结构动力学》1995,24(6):811-834

Two-storey-building frames have been designed and built in an effort to investigate the pounding phenomenon of adjacent buildings during earthquakes. Static tests have been first performed to determine the static characteristics and the support conditions of the test structures. Sinusoidal and random acceleration signal tests have been subsequently performed to determine the dynamic characteristics of the test structures. Two series of tests were carried out using the shaking table simulator. In the first case, the dynamic response has been recorded without pounding, while in the second case, the test structures have been placed with zero-gap separation and pounding was induced. Input energy time histories were correlated and compared with and without pounding. The experimental results were compared with analytical ones based on a formulation of the contact impact problem by the Lagrange multiplier method. Good agreement between the experimental and the analytical results was achieved.  相似文献   

Effects of temperature-dependent material properties and radioactive heat production on simple basin subsidence models     

Richard A. Ketcham  Eric C. Beam  Michelle A. Kominz 《Earth and Planetary Science Letters》1995,130(1-4):31-44

The effects of applying laboratory-derived material parameters to simple thermal basin subsidence models are examined. The temperature-dependent properties of thermal conductivity, specific heat and the coefficient of thermal expansion are considered, as well as conductivity contrasts between the crust and mantle and lithosphere-scale radiogenic heat production. The effects of conductivity and radioactivity are complementary, and can be predicted from the way in which they influence the initial and final steady-state geothermal gradient. A convex-up initial gradient, such as is generated by the conductivity and radioactivity functions and is also assumed to be the case based on independent evidence, will lead to more initial subsidence than in a simple constant-parameter model. The final subsidence will also be greater in the modified model, due to the fact that the stretching event will result in a lithospheric column which is intrinsically cooler than in the pre-deformation case. Because the coefficient of thermal expansion rises with increasing temperature, including its temperature dependence will result in a model with substantially less initial subsidence than one with a constant value. When these parameters are combined into a single model, the initial subsidence is approximately 15–20% less than in the constant-parameter model if radioactivity is not included, and 10% less if it is, while the final subsidence is about 5% greater without radioactivity and 7–9% greater with radioactivity included. Depending on the magnitude of extension, these effects can translate into differences of tens to hundreds of meters when compared to the constant-parameter model.  相似文献   

Detecting Changes in Ground Water Quality at Regulated Facilities     

Jim C. Loftis  Jane Harris  Robert H. Montgomery 《Ground Water Monitoring & Remediation》1987,7(1):72-76

The Resource Conservation and Recovery Act (PL 94–580) and related federal and state legislation have mandated routine monitoring of ground water quality at regulated facilities. The objective of the required monitoring activities is detection of adverse changes in ground water quality caused by the facilities.
Both failure to detect pollution and an incorrect determination of pollution can be very expensive. It is crucial, therefore, that monitoring programs be designed and operated to provide statistically sound information. It is equally important that users of ground water quality data understand the nature and limitations of information from monitoring.
To address the preceding issues, the authors present a general approach to analyzing ground water quality data in light of the stated monitoring objective. The suggested approach accounts for "natural" variation in background water quality through pairing of observations. The limitations of quarterly sampling for detecting small changes in quality over a short time frame are discussed.  相似文献   

Vertical distribution of plankton in the skagerrak in relation to doming of the seasonal thermocline     

R.D. Pingree  P.M. Holligan  G.T. Mardell  R.P. Harris 《Continental Shelf Research》1982,1(2):209-219

In the central Skagerrak between Norway and Denmark, the seasonal thermocline tends to be relatively shallow (10 to 15 m) probably due to geostrophic effects. An investigation of phytoplankton distribution in this region in late August 1981 showed the presence of an intense subsurface chlorophyll maximum (up to 30 γ 1⁻ Chl a) at a temperature of <6°C, dominated by coccolithophores and the dinoflagellate, Prorocentrum minimum. Data are presented on the vertical distribution of zooplankton in relation to these phytoplankton populations.  相似文献   

A review of the premium-protection method and its possible application in detection of displacements     

E. Clerici  M. W. Harris 《Journal of Geodesy》1983,57(1-4):1-9

A statistical technique using the concepts of Premium-Protection for error detection is applied to deformation measurement. The most attractive aspect of the method is the expression of test values involved in terms of size of deformation (within the limits of a particular design) to be detected. As a demonstration observations from a dam settlement survey are analysed.  相似文献   

Estimation of uranium endowment by subjective geological analysis—a comparison of methods and estimates for the San Juan Basin,New Mexico     

DeVerle P. Harris  Francis J. Carrigan 《Mathematical Geosciences》1983,15(1):227-227

This study investigates how estimates of uranium endowment made by a geologist using an appraisal system that is based upon a formalization of geoscience and decision rules compare with estimates made by informal and unconstrained intuitive processes. The motivation for this study derives from the premise that formalization of decisions would mitigate the heuristic biases and hedging that may result from the use of unconstrained intuitive processes. Estimates of the uranium endowment of the San Juan Basin of New Mexico by four methodologies are compared in this study. These methods, ranked from top to bottom by degree of decomposition (mitigating of heuristic bias)and control on hedging, are as follows Implicit 2 1.5 × 10⁶ s.t. of U₃O₈ Implicit 1 1.6 × 10⁶ s.t. of U₃O₈ NURE (1980) 2.4 × 10⁶ s.t. of U₃O₈ Appraisal system 3.9 × 10⁶ s.t. of U₃O₈ The magnitude of expected uranium endowment estimated by these methods, ranked from smallest to largest, is in this same order. With the exception of the NURE estimates, the magnitude of the variance (uncertainty)of uranium endowment, ranked from smallest to largest, also is in this same order. These results prompt the suggestion that the more decomposed and formalized the estimation procedure, the greater the expected value and the variance of uranium endowment. Equivalently, predicating U ₃ O ₈ endowment estimation strictly upon that part of the geologist's geoscience that is useful in making U ₃ O ₈ endowment estimates and upon his understanding of the region's history produced larger estimates than have previously been reported. However, this method of estimation also shows that uncertainty about the actual state of U ₃ O ₈ endowment is much greater than previously described.  相似文献   

Alteration of oceanic crust and geologic cycling of chlorine and water   总被引：1，自引：0，他引：1  

Emi Ito  David M Harris  Alfred T Anderson 《Geochimica et cosmochimica acta》1983,47(9):1613-1624

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