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991.
高温高压下流体中电解质的活度系数在地球化学领域有着广泛的应用。本实验测量了100—500℃、0.11—12GPa下0.01mol/L KCl溶液的电导率,并利用Hueckel方程由实验确定的摩尔电导和极限摩尔电导计算出了KCl的平均摩尔活度系数。平均摩尔活度系数随温度升高而减小,随压力升高而增大,而在高温高压下随温度压力的升高几乎保持恒定。 相似文献
992.
S. Harrison J. Molson H. Abercrombie J. Barker D. Rudolph R. Aravena 《Hydrogeology Journal》2000,8(6):608-622
Discovery of high contents of methane gas in coals of the Mist Mountain Formation in the Elk River valley, southeastern British
Columbia, Canada, has led to increased exploration activity for coal-seam gas (CSG). CSG production requires groundwater abstraction
to depressurize the coal beds and to facilitate methane flow to the production wells. Groundwater abstraction will have hydrodynamic
effects on the flow system, and an understanding of the groundwater flow system is needed to evaluate these effects. The purpose
of this paper is to describe the groundwater flow system in the area by means of a groundwater flow model and interpretation
of hydrochemical and isotopic analyses of groundwater and surface water.
Groundwater flow for the Weary Creek exploration area is modeled in two vertical sections. The model domains, based on classic
upland–lowland conceptual flow models, are approximately 10,000 m long and 4,000 m deep. Each consists of a fixed water-table
boundary and no-flow boundaries along the traces of major faults. Steady-state groundwater flow is calibrated to hydraulic-head,
streamflow, and groundwater-recharge data. Simulated steady-state velocity fields define regional and local flow components
consistent with the conceptual model.
The results are consistent with regional trends in δ2H, δ18O, tritium, and TDS, which define two distinct groundwater groups (A and B) and a third of intermediate composition. An active,
shallow, local flow component (group A) is recharged in beds cropping out along subdued ridges; this component discharges
as seeps along lower and mid-slope positions in the southern part of the study area. The waters are tritiated, relatively
enriched in δ2H and δ18O, and have low TDS. A deeper regional flow component (group B), which originates at a higher altitude and which discharges
to the Elk River valley bottom, is characterized by non-tritiated groundwater with relatively depleted δ2H and δ18O, and higher TDS.
Groundwater contributes less than 10% of the total direct flow to the Elk River, as indicated by flow measurements and by
the absence of group A and group B characteristics in the river water. Thus it is hypothesized that groundwater extraction
during CSG production will have little impact on the river. The groundwater flow model developed in this work is used in a
companion paper to further test this hypothesis.
Electronic Publication 相似文献
993.
Two stages of isotopic exchanges experienced by the Ertaibei granite pluton, northern Xinjiang, China 总被引:1,自引:0,他引:1
LIU Wei 《中国科学D辑(英文版)》2000,43(6):605-616
18O/16O and D/H of coexisting feldspar, quartz, and biotite separates of twenty samples collected from the Ertaibei granite pluton,
northern Xinjiang, China are determined. It is shown that the Ertaibei pluton experienced two stages of isotopic exchanges.
The second stage of18O/16O and D/H exchanges with meteoric water brought about a marked decrease in the δ18O values of feldspar and biotite from the second group of samples. The D/H of biotite exhibits a higher sensitivity to the
meteoric water alteration than its18O/16O. However, the first stage of18O/16O exchange with the18O-rich aqueous fluid derived from the dehydration within the deep crust caused the Δ18OQuartz-Feldspar reversal. It is inferred that the dehydration-melting may have been an important mechanism for anatexis. It is shown that
the deep fluid encircled the Ertaibei pluton like an envelope which serves as an effective screen to the surface waters. 相似文献
994.
K. Theunissen N. L. Dobretsov A. Korsakov A. Travin V. S. Shatsky L. Smirnova and A. Boven 《Island Arc》2000,9(3):284-303
Abstract In northern Kazakhstan the WNW striking Kokchetav megamélange includes different crustal sequences with high‐pressure/ultrahigh‐pressure (HP/UHP) remnants of their 540–520 Ma subduction metamorphism. Two domains separated by the north‐east trending Chaglinka fault are distinguished. The western domain exhibits NE–SW structures within a single Kumdy–Kol megaunit of diamond‐bearing UHP metasediments and high‐temperature (HT) eclogites. The eastern domain consists of the composite Kulet megaunit with the Kulet UHP unit (coesite‐bearing metasediments, whiteschists and eclogites), the Enbek–Berlyk medium‐pressure (MP) unit (kyanite‐bearing, high‐alumina rocks with interleaved coronitic metagabbro), and ortho‐ and paragneisses with eclogites and amphibolites included. All eclogites in the eastern domain are of the relatively low temperature (LT) type. Sillimanite is common and appears after kyanite in the sheared MP unit. A regional and moderately ESE plunging linear fabric coincides with the fold‐axis of the foliation poles from the eastern domain. Whether this also reflects a regional top to the WNW transport, as inferred from the dextral strike‐slip on steeply to SSW dipping foliation, needs further study. Top to the WNW shear is shown by weakly inclined low pressure (LP) cordierite rocks that flank the eastern domain in the south. Some new 39Ar/40Ar mica cooling ages (519, 521 Ma) from the Kulet UHP micaschists reflect the same early stage evolutionary event as was previously shown for the Kumdy–Kol UHP rocks (515, 517 Ma) in the west. Similar 39Ar/40Ar ages (500, 517 Ma) are recorded by micas and amphibole that outline a top to NNW shear fabric in the non‐subducted Proterozoic basement, north of the megamélange. A 447 Ma overprint of the MP sequences is considered to reflect the strike‐slip deformation with sillimanite and the reworking of an early kyanite‐bearing tectonite. Biotites from the LP cordierite rocks yielded approximately 400 Ma 39Ar/40Ar ages. In case they reflect the WNW shear deformation, the latter is considered to be associated with a regional granite magmatism (420–460 Ma) extending south of the eastern domain. In their present different structural domains the Kulet and Kumdy–Kol UHP units display a similar early stage event. Subsequent LP deformation, which is likely to be associated with regional granite magmatism (420–460 Ma), is assumed to have obliterated any common or uniform early exhumation structure for the whole megamélange. The north‐east structured Kumdy–Kol domain is assumed to have preserved the most information about the early stage exhumation. This domain is at an angle to the regional WNW strike of the megamélange. 相似文献
995.
G. Kallianpur V. G. Papanicolaou 《Stochastic Environmental Research and Risk Assessment (SERRA)》2000,14(1):33-49
We calculate explicitly some expectations (integrals over Hilbert spaces) of functionals of Gaussian random fields. Our work
is inspired by the formulas for the harmonic oscillator. We also show how to do similar calculations by considering continuum
limits of sequences of coupled harmonic oscillators. The results obtained in this work have applications in the study of random
media, renormalization and scaling, and in engineering perturbation analysis. 相似文献
996.
Simple straightforward methods are applied to testtheir ability to detect the non-linear response of thesoil. Recordings of the main shock and aftershocks ofthe 1995, Hyogo-ken Nanbu (Kobe) earthquake are used.Non-linear effects are investigated using twodifferent techniques, on a collection of data for 12sites situated on different geological structures inthe Kobe and Osaka areas. The first method used is theso-called receiver functions technique (Langston,1979), which consists of computing the spectral ratiobetween horizontal and vertical components of motion.This ratio has been shown to reveal the fundamentalfrequency of a site (Lachet and Bard, 1994; Lachet etal., 1996; Theodulidis et al., 1995, 1996). For eachsite, recordings of the main shock and a set ofaftershocks are considered. The variation of thisspectral ratio for different values of the maximumacceleration recorded at a site is investigated. Bothvariations of the amplitude of the H/V ratio (due tonon-linear behavior, on the horizontal components inparticular) and of the frequency position of theamplified band-width are observed. The secondtechnique used in this study is related to thevariation of the high frequency content of therecordings during the main-shock and its aftershocks.The high frequency spectral decay of the motion,characterized by parameter, is assumed to berelated mainly to the near-surface attenuation. Itshould then increase with increasing peak velocity, incase of non-linearity. The value of kappa iscalculated for the 12 sites in the Kobe area, fordifferent types of soil conditions, and againdifferent values of peak ground acceleration.Variations of kappa are then related to non-linearbehavior of the soil during the Kobe earthquake. 相似文献
997.
N. Mantajit 《Environmental Geology》2000,39(7):750-752
The paper describes the activities and objectives of the Department of Mineral Resources in the field of environmental geology.
This approach is still a comparatively new for Thailand and presently comprises different programs: environmental geology
for regional planning, seismic hazards, flooding/landslides, coastal management and geosites conservation. The Environmental
Geology Section of the Department is the relevant administrative unit. The technical work and the related documentations focus
on rising public awareness and integration of geo-information into land-use planning and land development.
Received: 23 April 1999 · Accepted: 8 June 1999 相似文献
998.
A Study of DMS Oxidation in the Tropics: Comparison of Christmas Island Field Observations of DMS, SO2, and DMSO with Model Simulations 总被引:2,自引:0,他引:2
G. Chen D. D. Davis P. Kasibhatla A. R. Bandy D. C. Thornton B. J. Huebert A. D. Clarke B. W. Blomquist 《Journal of Atmospheric Chemistry》2000,37(2):137-160
This study reports comparisonsbetween model simulations, based on current sulfurmechanisms, with the DMS, SO2 and DMSOobservational data reported by Bandy et al.(1996) in their 1994 Christmas Island field study. For both DMS and SO2, the model results werefound to be in excellent agreement with theobservations when the observations were filtered so asto establish a common meteorological environment. Thisfiltered DMS and SO2 data encompassedapproximately half of the total sampled days. Basedon these composite profiles, it was shown thatoxidation of DMS via OH was the dominant pathway withno more than 5 to 15% proceeding through Cl atoms andless than 3% through NO3. This analysis wasbased on an estimated DMS sea-to-air flux of 3.4 ×109 molecs cm-2 s-1. The dominant sourceof BL SO2 was oxidation of DMS, the overallconversion efficiency being evaluated at 0.65 ± 0.15. The major loss of SO2 was deposition to theocean's surface and scavenging by aerosol. Theresulting combined first order k value was estimated at 1.6 × 10-5 s-1. In contrast to the DMSand SO2 simulations, the model under-predictedthe observed DMSO levels by nearly a factor of 50. Although DMSO instrument measurement problems can notbe totally ruled out, the possibility of DMSO sourcesother than gas phase oxidation of DMS must beseriously considered and should be explored in futurestudies. 相似文献
999.
Bender Elements在测试土样剪切波速中的应用 总被引:4,自引:0,他引:4
本文以作者在香港理工大学土木与结构工程系设计制作的一套BenderElements为例,介绍了BenderElements的原理、发展历史、应用范围、使用方法和注意事项等。BenderElements是由压电陶瓷材料制成的,在拉伸、压缩作用下,会产生正、负电荷,反过来,给它施加正、负电荷后,它又可产生弯曲振动,正是利用它的这一特性,将其作成接收和发射装置,来测试土样的剪切波速Vs。BenderElements在安装使用时,防水和静电屏蔽十分关键。Vs可在场地地震反应、液化判别、动力基础设计、检测地基改良效果等方面获得应用。震相识别的原则是接收信号的第一个峰值为到时。 相似文献
1000.
The Ardara pluton as part of the Donegal batholith was intruded into Neoproterozoic metasediments and metadolerites at mid-crustal
levels. The emplacement mechanism of the Ardara granite is very controversial, and mechanisms ranging from diapirism, ballooning
and stoping followed by nested diapirism have been proposed. Magnetic fabrics, rock fabrics and K/Ar dating of micas are used
here to constrain the emplacement history. The compositional zoning of the Ardara pluton is clearly reflected in the different
bulk magnetic susceptibilities between the outer quartz monzodiorite and the central granodiorite, whereas the intervening
tonalite is of intermediate nature. The magnetic carriers are characterized by the anisotropy of the magnetic susceptibility
(AMS), thermomagnetic measurements and through high field analyses (HFA). The separation of the ferrimagnetic and paramagnetic
contributions revealed that biotite and magnetite control the AMS in the quartz monzodiorite. Both minerals are oriented in
such a way that their summed contribution is constructive and originates from the shape fabric of magnetite and the texture
of biotite. Biotite is responsible mainly for the AMS in the tonalite and granodiorite. The magnetic foliation can be directly
related to the macroscopic foliation and also to the D4 structures in the country rocks. The foliation is consistent with
the geometry of the roughly circular shape and has a mostly steep to vertical dip. Towards the central granodiorite the magnetic
foliation dies out, although plagioclase texture measurements indicate a weak magmatic shape fabric. With the exception of
the tail, the Kmax axes (magnetic lineation) vary from steeply to gently plunging. The so-called lineation factor is approximately 1.01 and
therefore points to a less significant axial symmetry. These observations coincide with strain estimates on mafic enclaves
that show a very consistent pattern of K ∼0 flattening strain. Texture analyses of biotite and quartz additionally support
the observations made by the strain analyses and the magnetic fabric data. Microstructural investigations give evidence that
the fabrics are associated with the emplacement over a range of temperatures from truly magmatic to high-temperature solid-state
conditions. The age of the intrusion is still under discussion, but a new cooling age was determined by K/Ar dating of biotite
at 403.7±8 Ma corresponding to a temperature range between 450 and 300°C. For a mylonite along the southern contact between
the Ardara pluton and the country rock a K/Ar muscovite age of 378.8±7 Ma indicates a minimum age for the shear zone when
the Ardara pluton must have already been cooled down below 350±50°C.
Received: 28 January 1999 / Accepted: 28 December 1999 相似文献