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991.
Geophysical investigations using 2-D DC resistivity were carried out on old parts of two similar landfills, with waste of
different ages. The data sets, which included high data density in both vertical and horizontal directions, were interpreted
with 2-D smoothness constrained inversion. The landfills were excavated after the surveying. The objective was to test the
capability of the resistivity method as a pre-characterization technique. The objectives were only partially fulfilled. First,
the moisture content was the parameter that appeared to exert the dominant control over the resistivity distribution of the
landfill. The most important potential information that can be recovered is, therefore, an indication of the waste piles hydraulics.
Second, it was neither possible to estimate the amount of recoverable soils, nor to correlate the type of waste with the resistivity
models. However, discrete anomalies were identified, and if specific materials are searched for, the resistivity models indicate
possible places to search.
Received: 23 July 1998 · Accepted: 20 October 1998 相似文献
992.
The degree sheet Aeromagnetic maps up to 17‡N, acquired from the Geological Survey of India, have been manually redigitised
at 6 minute intervals to study the long wavelength anomalies over peninsular India. These data have been collected at different
survey altitude, epochs, flight line directions, etc. Great care has been taken to correct the total field map and remove
the contribution due to the core field and prepare an accurate crustal anomaly map. For the first time, a regional map, depicting
the NW-SE structural features north of the orthopyroxene isograd with the essentially E-W features to the south of it and
revealing several well known structures, is presented. The analytical signal is calculated to delineate the source fields
of these anomalies. It dramatically maps the charnockites and is able to delineate the orthopyroxene isograd. In the Dharwar
region the magnetic signatures are associated with the intrusives/ iron ore bodies. Thus, we find that the source rocks of
the aeromagnetic anomalies are the host province of charnockites in the SGT and the intrusives/iron ore bodies in the Dharwar
belt. Gravity residuals are calculated and a tectonic map of the region is presented from the combined geopotential data. 相似文献
993.
Fractal analysis of the Oyo River, cave systems, and topography of the Gunungsewu karst area, central Java, Indonesia 总被引:1,自引:0,他引:1
Sari B. Kusumayudha M. T. Zen Sudarto Notosiswoyo Rudy Sayoga Gautama 《Hydrogeology Journal》2000,8(3):271-278
Gunungsewu, the southernmost subzone of the Southern Mountains, central Java, is a classic karst terrain, bounded by the
Oyo River on the north and the Indian Ocean on the south. In this study, the Oyo River, the main drainage in the area, is
divided into 14 segments, and the fractal dimension of each segment is determined by the box-counting method. The 14 segments
show various values of fractal dimensions, which are controlled by lithology and geologic structures of the area that is being
dissected by the river. Easily eroded lithologies have larger fractal dimensions, and the value changes abruptly when the
river crosses faults. Fractal dimensions of six underground rivers in the Bribin, Sodong, Semuluh, Jomblang, Soga, and Sumurup
caves, and the surface topography above the caves were also determined. The caves have fractal dimensions that range from
1.043 ±0.01 to 1.08±0.01; the surface topography has fractal dimensions that range from 1.49±0.01 to 1.732±0.01. The fractal
dimension of an underground river is proportional to the fractal dimension of the surface topography over the passage. Larger
fractal dimensions of underground rivers are associated with smaller flow rates of the rivers.
Received, June 1998Revised, March 1999, August 1999, February 2000Accepted, February 2000 相似文献
994.
A. V. Mokhov P. M. Kartashov T. A. Gornostaeva O. A. Bogatikov 《Doklady Earth Sciences》2011,441(2):1692-1694
Native ytterbium first identified in a single brownish orange glass fragment collected from the deepest part (184–189 cm)
of the bore core delivered from the Mare Crisium of the Moon to the Earth by the Luna-24 Automatic Station is described. As
follows from X-ray elemental maps, the ytterbium grain is metallic. Possible mechanisms of its formation and reasons for its
elevated corrosion stability are discussed. 相似文献
995.
T. Hueckel 《国际地质力学数值与分析法杂志》1997,21(1):43-72
Isothermal chemo-elasto-plasticity of clays is discussed, to describe strains induced in clay by permeation of it with a low dielectric constant organic contaminant, in the presence of stress. The strain is crucial in controlling permeability changes in chemically affected clay barriers of landfills and impoundments. The theory encompasses chemical softening or yield surface reduction, coefficient of chemical reversible expansion or contraction due to mass concentration increase, as well as chemical sensitivity of bulk plastic modulus. The experiments on chemistry and stress dependent permeability of Sarnia clay performed by Fernandez and Quigley (1985, 1991) are interpreted using this model. The numerical representations of the chemo-plastic softening function and the chemo-elastic strain function, as well as plastic bulk modulus sensitivity to concentration are evaluated for dioxane and ethanol. Specific requirements for the tests for chemo-plastic behavior of clays are discussed. © 1997 by John Wiley & Sons, Ltd. 相似文献
996.
High-Mg# andesitic lavas of the Shisheisky Complex,Northern Kamchatka: implications for primitive calc-alkaline magmatism 总被引:1,自引:0,他引:1
J. A. Bryant G. M. Yogodzinski T. G. Churikova 《Contributions to Mineralogy and Petrology》2011,161(5):791-810
Primitive arc magmatism and mantle wedge processes are investigated through a petrologic and geochemical study of high-Mg#
(Mg/Mg + Fe > 0.65) basalts, basaltic andesites and andesites from the Kurile-Kamchatka subduction system. Primitive andesitic
samples are from the Shisheisky Complex, a field of Quaternary-age, monogenetic cones located in the Aleutian–Kamchatka junction,
north of Shiveluch Volcano, the northernmost active composite volcano in Kamchatka. The Shisheisky lavas have Mg# of 0.66–0.73
at intermediate SiO2 (54–58 wt%) with low CaO (<8.8%), CaO/Al2O3 (<0.54), and relatively high Na2O (>3.0 wt%) and K2O (>1.0 wt%). Olivine phenocryst core compositions of Fo90 appear to be in equilibrium with whole-rock ‘melts’, consistent
with the sparsely phyric nature of the lavas. Compared to the Shisheisky andesites, primitive basalts from the region (Kuriles,
Tolbachik, Kharchinsky) have higher CaO (>9.9 wt%) and CaO/Al2O3 (>0.60), and lower whole-rock Na2O (<2.7 wt%) and K2O (<1.1 wt%) at similar Mg# (0.66–0.70). Olivine phenocrysts in basalts have in general, higher CaO and Mn/Fe and lower Ni
and Ni/Mg at Fo88 compared to the andesites. The absence of plagioclase phenocrysts from the primitive andesitic lavas contrasts
the plagioclase-phyric basalts, indicating relatively high pre-eruptive water contents for the primitive andesitic magmas
compared to basalts. Estimated temperature and water contents for primitive basaltic andesites and andesites are 984–1,143°C
and 4–7 wt% H2O. For primitive basalts they are 1,149–1,227°C and 2 wt% H2O. Petrographic and mineral compositions suggest that the primitive andesitic lavas were liquids in equilibrium with mantle
peridotite and were not produced by mixing between basalts and felsic crustal melts, contamination by xenocrystic olivine,
or crystal fractionation of basalt. Key geochemical features of the Shisheisky primitive lavas (high Ni/MgO, Na2O, Ni/Yb and Mg# at intermediate SiO2) combined with the location of the volcanic field above the edge of the subducting Pacific Plate support a genetic model
that involves melting of eclogite or pyroxenite at or near the surface of the subducting plate, followed by interaction of
that melt with hotter peridotite in the over-lying mantle wedge. The strongly calc-alkaline igneous series at Shiveluch Volcano
is interpreted to result from the emplacement and evolution of primitive andesitic magmas similar to those that are present
in nearby monogenetic cones of the Shisheisky Complex. 相似文献
997.
Solubility curves of water-hydrogen fluid were studied using a high-pressure gas apparatus at a pressure of 200 MPa under
variable fluid composition in haplogranite (Ab
39
Or
32
Qtz
29, 950°C), Na-disilicate (Na2Si2O5, 950°C), and albite melts (1200°C). The mole fraction of hydrogen in experiments was controlled directly by Ar-H2 mixtures using a specially designed cell with a Shaw membrane. $
X_{H_2 }^{Ar - H_2 }
$
X_{H_2 }^{Ar - H_2 }
ranged from 0 to 1. In some experiments with haplogranite and Na-disilicate melts under oxidizing conditions, in order to
increase the accuracy of experimental parameters, the fugacities of oxygen and hydrogen were controlled using the double-capsule
technique and the solid-phase buffer mixtures Ni-NiO (NNO) and Co-CoO (CCO). The addition of H2 to the H2O-saturated systems ($
X_{H_2 }^{H_2 O - H_2 }
$
X_{H_2 }^{H_2 O - H_2 }
≥ 0.012) results in the appearance of a distinct maximum on the solubility curves at $
X_{H_2 }^{H_2 O - H_2 }
$
X_{H_2 }^{H_2 O - H_2 }
= 0.05–0.07 (H2 mole fractions were calculated for real H2O-H2 mixtures of real gases), and the maximum content of H2O-H2 fluid increases relative to the H2O-saturated melts by 1.51 wt % for haplogranite melt at $
X_{H_2 }
$
X_{H_2 }
= 0.063, 2.68 wt % for albite melt at $
X_{H_2 }
$
X_{H_2 }
= 0.066, and 3.54 wt % for Na-disilicate melt at $
X_{H_2 }
$
X_{H_2 }
= 0.067. A further increase in H2 content in the gas mixture decreases the solubility of H2O-H2 fluid in the melts, and under pure H2 pressure, the contents of fluid components are 0.08 wt % in haplogranite melt and 0.06 wt % in albite melt. The 1H NMR study of aluminosilicate and Na-silicate glasses obtained under the pressure of H2O and H2O-H2 fluids suggests different mechanisms of the dissolution of H2O and H2O-H2 fluids in magmatic melts. In addition to the spectra of dissolved water fluid, the spectra of quenched glasses synthesized
under H2O-H2 fluid pressure exhibited a narrow line of molecular hydrogen with a width at half height of 1.8–2.0 kHz at $
X_{H_2 }
$
X_{H_2 }
≥ 0.653 for albite and $
X_{H_2 }
$
X_{H_2 }
≥ 0.063 for Na-disilicate and two lines at $
X_{H_2 }
$
X_{H_2 }
≥ 0.063 for the haplogranite composition. 相似文献
998.
Mechanical aspects of sedimentary basin formation: development of integrated models for lithospheric and surface processes 总被引:1,自引:0,他引:1
S. Cloetingh R. T. Van Balen M. Ter Voorde B. P. Zoetemeijer T. Den Bezemer 《International Journal of Earth Sciences》1997,86(2):226-240
Different assumptions for the thermo-mechanical properties of the lithosphere strongly affect predictions inferred from quantitative sedimentary basin modeling. Examples from various basins, selected as natural laboratories, illustrate the importance of incorporating a finite strength of the extending lithosphere in forward stratigraphic modeling of large-scale basin stratigraphy. Current models can effectively couple erosion at uplifted rift shoulders of extensional basins with the basin fill architecture of the subsiding basin compartments. Modeling of the synrift strata integrates spatial scales characteristic for subbasins, such as the Oseberg field in the North Sea, with large-scale lithospheric properties characterizing the bulk strength of extending lithosphere. Modeling of compressional basins in foreland fold-and-thrust-belt settings can effectively link lithospheric flexure with surface processes. Scales pertinent to short-term spatial and temporal variations in basin fill and basin deformation can now be addressed, allowing the quantitative investigation of consequences of different modes of thrusting for basin fill geometry and facies characteristics. 相似文献
999.
GORDON T. BOWLES 《地质学报》1934,13(1)
INTRODUCTION During the year 1930-31, while holding a schularship from the Harvard-Yenching Institute, I received permission from the Institute to engage in ethnological and anthropological research on behalf of the University Museum 相似文献
1000.
This paper reports the results of pilot‐study efforts to develop methods to profile quartzite, a rock type to which geochemical and other sourcing techniques have only rarely been applied. The long‐term goal of the research is to fingerprint sources of quartzite in the Gunnison Basin, southwest Colorado, used by Paleoindian people ca. 11,500–8,000 years ago to make stone tools. Success would facilitate reconstruction of Paleoindian mobility in the Southern Rocky Mountains and potentially anywhere prehistoric people used quartzite. The goals of this paper are more modest: to demonstrate that a small‐scale exploration of sourcing techniques suggests reason for optimism that quartzites may be amenable to source discrimination. For the same twenty Gunnison Basin quartzite samples, this study evaluated petrography, ultraviolet fluorescence (UVF), wavelength dispersive X‐ray fluorescence (WD‐XRF), instrumental neutron activation analysis (INAA), and inductively coupled plasma mass spectrometry—both acid‐digestion (AD‐ICP‐MS) and laser ablation (LA‐ICP‐MS)—as means to differentiate among the specimens and the sources they represent. Although more testing is needed to verify and refine our results, the study suggests there is potential for petrography, INAA, and both versions of ICP‐MS to discriminate among quartzites from different source localities in the Gunnison Basin. The greatest potential for discriminating among different sources of quartzite in the Gunnison Basin may lie in a methodology combining petrographic analysis and LA‐ICPMS. Future testing is required to evaluate this two‐fold approach. © 2008 Wiley Periodicals, Inc. 相似文献