共查询到19条相似文献，搜索用时 203 毫秒
1.
氡的多参数测量用于非铀矿地质问题 总被引：1，自引：1，他引：1
在非铀矿地质问题中,常存在着一种或几种氡的弱异常(如222Rn、220Rn等).在选用测氡方法来解决这类问题时,要求它具有高灵敏度、高测量精度和多测量参数的特点。选用静电α卡法、α杯法的多参数测量技术,在圈定岩脉边界、区分岩脉性质、找寻蓄水构造、确定油田范围的应用中取得了明显的效果, 相似文献
2.
本文介绍了一种新的野外测222Rn法——液体闪烁测222Rn法。该法取样时间短,操作简单,灵敏度高,重复性好,成本低廉,并能有效地克服钍射气的干扰。野外应用取得了较好的效果。 相似文献
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应用自然α杯法壤中氡气测量来评价金和多金属矿床所形成的化探异常的工作做得还不多。为了开拓氡气测量应用的新领域和为可靠评价化探异常增加一个新指标,我们在位于半干旱草原景观的新疆某Au异常区和黄土沟壑景观的甘肃蛟龙掌多金属黄铁矿区进行了初步尝试。结果表明:(1)Rn气异常令人满意地圈定了已知Au矿化体的赋存部位(包括隐伏部分),并圈出了几处找Au远景区段(其中一处已经验证,结果表明推测基本正确)。说明自然α杯法氡气测量可以作为圈定构造破碎带控制的隐伏Au矿化体的有效手段之一。与其他化探方法配合,可为找寻含Au构造破碎带提供可靠的信息。(2)在黄土和第三系红色粘土埋深20m左右的多金属矿化带及构造破碎带上方具有Rn气弱异常。说明自然α杯法氡气测量在黄士覆盖区用于找寻隐伏多金属矿化是有效的。 相似文献
5.
为了提高探测地下水的地质效果,近些年来国内外采用了放射性物探方法探测地下水,取得了较好的成果。目前采用的方法主要有γ法和α径迹法[1]。比较起来,α径迹法的灵敏度较高,探测深度较大,应用于寻找新构造(指晚期构造)裂隙水[2]的效果比γ法为好。 相似文献
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第四纪沉积物磁性勘查油气法的原理及应用 总被引：3，自引：0，他引：3
本文介绍了利用第四纪沉积物磁性调查油气的原理,地下油气藏会在近地表第四纪沉积物中产生磁性矿物并形成多种磁性参量异常。检验了形成磁性异常的磁性矿物的种类;发现了油田地区土壤中存在着趋磁细菌。在5个油田地区近450km2范围应用该方法调查油气分布的研究结果表明,各种磁性异常(κ、Mn、Mr、Ir、Iκ)呈综合异常的形式,它们的形成及分布特征受油气活动、通道及环境条件的控制。实际资料证实,磁性综合异常能反映油田地区油气活动的分布状态。该方法作为综合勘查方法之一,应进一步推广。 相似文献
8.
本文研究了An(219Rn)的野外现场测量技术,提出了原地测量法和桶中测量法.列举了在已知矿床上实测的一些结果,讨论了该技术的应用前景. 相似文献
9.
在美国采用地球化学方法勘探油气已有30年了,已经取得了大量的成果。壤中吸附烃抽提技术以及其测量分析都已得到了发展提高。实验表明,在首次测量后数年重新采样,异常可以重现;另一方面,随着油田的开采,烃异常逐渐变弱,最后趋于消失。尽管与大型油气藏相联系的晕圈(halo)这种基本异常模式继续被发现,亦已认识到其他类型的烃分布模式。烃测量技术有助于评价穹隆构造翼部的含油性,在获得适当的资料后,可以在构造顶部布钻。如例案所述,烃测量后指出在刺穿型穹隆构造的翼部有一油气藏分布。 相似文献
10.
210Pb具有百年时间尺度沉积计年的重要价值。210Pbex计年假设：沉积物是封闭系统；进入水体的210Pb能有效地转移到沉积物中并不发生沉积后迁移；非过剩210Pb与其母体226Ra保持平衡。210Pbex计年可用稳定输入通量-稳定沉积物堆积速率模式、常量初始浓度模式或恒定补给速率模式。沉积物柱芯必须保持原态并以0．5～1cm间隔分截；用相应层节226Ra校正。沉积物表层混合作用及222Rn的丢失可能导致顶部210Pbex异常。季节性缺氧湖泊沉积物顶部可能存在210Pb及210Po的再迁移。210Pb与137Cs两种计年方法原理上具有根本差别。210Pb，137Cs与沉积纹理方法对比是准确计年的重要保证。 相似文献
11.
Radon concentrations in soil gas,considering radioactive equilibrium conditions with application to estimating fault-zone geometry 总被引：1，自引：0，他引：1
A calculation method for determining the amount of Rn isotopes and daughter products at the start of measurement (CRAS) is
proposed as a more accurate means of estimating the initial Rn concentration in soil gas. The CRAS utilizes the decay law
between 222Rn and 220Rn isotopes and the daughter products 218Po and 216Po, and is applicable to α-scintillation counter measurements. As Rn is both inert and chemically stable, it is useful for
fault investigation based on the soil gas geochemistry. However, the total number of α particles emitted by the decay of Rn
has generally been considered to be proportional to the initial Rn concentration, without considering the gas condition with
respect to radioactive equilibrium. The CRAS method is shown to be effective to derive Rn concentration for soil gases under
both nonequilibrium conditions, in which the total number of decays increases with time, and equilibrium conditions, which
are typical of normal soil under low gas flux. The CRAS method in conjunction with finite difference method simulation is
applied to the analysis of two active fault areas in Japan, and it is demonstrated that this combination could detect the
sharp rises in 222Rn concentrations associated with faults. The method also allows the determination of fault geometry near the surface based
on the asymmetry variation of the Rn concentration distribution when coupled with a numerical simulation of 222Rn transport. The results for the new method as applied to the two case studies are consistent with the data collected from
the geological survey. It implies that the CRAS method is suitable for investigating the fault system and interstitial gas
mobility through fractures. The present analyses have also demonstrated that high Rn concentrations require the recent and
repeated accumulation of 222Rn parents (230Th and 226Ra) in fault gouges through deep gas release during fault movement. 相似文献
12.
More than 3,200 indoor radon-222 (222Rn) measurements were made seasonally in an area of about 1,000 square kilometers of the Coastal Plain and Piedmont physiographic provinces in Virginia, U.S.A. Results of these measurements indicate that some geological units are associated, on the average, with twice as much indoor222Rn as other geological units, and that indoor222Rn varies seasonally. The Kruskal-Wallis test was used to test whether indoor222Rn concentrations for data gathered over the winter and summer seasons differ significantly by rock unit. The tests concluded that indoor222Rn concentrations for different rock units were not equal at the 5-percent significance level. The rocks associated with the highest median indoor222Rn concentration are specific rocks in the Mesozoic Culpeper basin, including shale and siltstone units with Jurassic diabase intrusives, and mica schists in the Piedmont physiographic province. The pre-Triassic Peters Creek Schist has the highest ranking in terms of indoor222Rn concentration. The rocks associated with the lowest indoor222Rn concentrations include coastal plain sediments, the Occoquan Granite, Falls Church Tonalite, Piney Branch Mafic and Ultramafic complex, and unnamed mafic and ultramafic inclusions, respectively. The rocks have been ranked according to observed222Rn concentration by transforming the average rank of indoor222Rn concentrations to z scores. 相似文献
13.
Analysis of the exchange of groundwater and river water by using Radon-222 in the middle Heihe Basin of northwestern China 总被引：9，自引：1，他引：8
In arid regions of western China, water resources come from mountain watersheds and disappear in the desert plain. The exchange of surface water and groundwater takes place two or three times in a basin. It is essential to analyze the interaction of groundwater with surface water to use water resources effectively and predict the change in the water environment. The conventional method of analysis, however, measures only the flow of a stream and cannot determine groundwater seepage accurately. As the concentration of Radon-222 (222Rn) in groundwater is much higher than in surface water, the use of 222Rn was examined as an indicator for the analysis of the interaction between surface water and groundwater. Measurement of the 222Rn concentration in surface water was conducted to detect groundwater seepage into a stream in the middle Heihe Basin of northwestern China. Furthermore, the simultaneous groundwater flow into and out of a stream from the aquifers was quantified by solving the 222Rn mass balance equation, in which the losses of gas exchange and radioactive decay of 222Rn are considered. Meanwhile, river runoff was gauged to determine the exchange rates between surface water and groundwater. The result shows that 222Rn isotope can be used as a good environmental tracer with high sensitivity for the interaction between surface water and groundwater, especially in the fractured aquifer system, karst aquifer system and discharge basins. 相似文献
14.
The mechanism of222Rn release into fracture fluids by direct alpha-recoil, lattice and grain boundary/micro-crack diffusion is discussed. Experimental measurements of222Rn release into surrounding air and water phases have been made for crystalline rock specimens with well defined surface areas. The222Rn flux from an infinite plane surface and hence the effective diffusion length of222Rn in the rock matrix has been estimated.The222Rn flux from plane crystalline rock surfaces has been used in conjunction with a simple hydrological model of the reservoir to calculate the222Rn content of the return fluids of a geothermal doublet circulation system. For given production rate and piezometric difference between the injection and production wells, the222Rn content of the return fluid is dependent upon the distribution of flow path lengths and fracture apertures in the reservoir. Matching of the calculated and experimental222Rn contents of the return fluids has been used to select appropriate parameters for the reservoir model and hence to estimate the extent of the heat-transfer surface. The model estimates the fracture width of the flow paths, total swept surface area and fracture volume within the reservoir. 相似文献
15.
Jae-Ha Yang Seong-Chun Jun Hyung-Pyo Kwon Kang-Kun Lee 《Environmental Earth Sciences》2014,71(1):407-417
Depth-discrete tracing of residual dense non-aqueous phase liquid (DNAPL) sources in the subsurface is of great importance in making decisions related to contaminated groundwater remediation. Temporal variations in the natural tracer 222Rn and contaminant concentrations in groundwater contaminated with multiple chlorinated contaminants, such as trichloroethene, carbon tetrachloride, and chloroform, were examined to trace residual multiple DNAPL contaminants at an industrial complex in Wonju, Korea. The 222Rn activities and multiple DNAPL concentrations in the groundwater fluctuated irregularly according to the groundwater recharge. The natural tracer 222Rn in groundwater present in the soil layer, originating from the underlying crystalline biotite granite, had a wide range from 29,000 to 179,000 Bq/m3, and total concentrations of chlorinated solvents ranged from 0.06 to 17.77 mg/l, indicating the ambiguous results of 222Rn for tracing the residual DNAPL sources. In this paper, a method is presented to locate zones with a high probability of containing depth-discrete residual multiple DNAPL sources using 222Rn and considering relative contaminant concentrations. The results demonstrate that the combination of the 222Rn activities as a natural tracer and the relative contaminant concentrations is able to be used as a useful tool for tracing residual DNAPLs. 相似文献
16.
Hajo Idriss Isam Salih Abdulaziz S. Alaamer M. Y. Abdelgalil Salih Ali Salih Amna M. Hasan Mohammed A. ELtahir Mustafa M. O. Ahamed 《Environmental Earth Sciences》2014,72(2):335-339
This study was conducted primarily to measure and map radon activity concentration in soil gas and to understand the effect of geology and lithology and meteorology on radon concentration. Portable radon meter has been used for the measurement of soil gas radon at 30 different locations around Uro and Korn area in eastern Nuba Mountain South Kordofan State. The results indicate that the activity concentrations of 222Rn in soil gas fall within the range of 20–1,359 Bq/m3 with geometric mean of 102.80 Bq/cm3. The obtained data show that samples around Uro have anomaly of 222Rn concentrations than the sample around Korn. The reason could be attributed to differences in the geological structure, lithology and climate parameters. GIS predicative map has shown that the elevated levels of radon concentration were measured in North study area. Upon comparing the results with global data, it was found that the obtained values are far below the reported range of India, Slovenia, Portugal and Syria. However, the range of 222Rn concentrations in the soil observed in this study is significantly high relative to similar data reported from Libya. The regression analysis has shown that no correlation was noted between radon concentrations, climatic parameters and trace element. 相似文献
17.
The Aral Sea has been shrinking since 1963 due to extensive irrigation and the corresponding decline in the river water inflow. Understanding of the current hydrological situation demands an improved understanding of the surface water/groundwater dynamics in the region. 222Rn and 226Ra measurements can be used to trace groundwater discharge into surface waters. Data of these radiometric parameters were not previously available for the study region. We determined 222Rn activities after liquid phase extraction using Liquid Scintillation Counting (LSC) with peak-length discrimination and analyzed 226Ra concentrations in different water compartments of the Amu Darya Delta (surface waters, unconfined groundwater, artesian water, and water profiles from the closed Large Aral Sea (western basin).The water samples comprise a salinity range between 1 and 263 g/l. The seasonal dynamics of solid/water interaction under an arid climate regime force the hydrochemical evolution of the unconfined groundwater in the Amu Darya Delta to high-salinity Na(Mg)Cl(SO4) water types. The dissolved radium concentrations in the waters were mostly very low due to mineral over-saturation, extensive co-precipitation of radium and adsorption of radium on coexisting solid substrates.The analysis of very low 226Ra concentrations (<10 ppq) at remote study sites is a challenge. We used the water samples to test and improve different analytical methods. In particular, we modified a procedure developed for the α-spectrometric determination of 226Ra after solid phase extraction of radium using 3M Empore™ High Performance Extraction Disks (Purkl, 2002) for the analysis of the radionuclide using an ICP sector field mass spectrometer. The 226Ra concentration of 17 unconfined groundwater samples ranged between 0.2 and 5 ppq, and that of 28 artesian waters between <0.2 and 13 ppq. The ICP-MS results conformed satisfactorily to analytical results based on γ-measurements of the 222Rn ingrowth after purging and trapping on super-cooled charcoal. The 226Ra concentrations were positively correlated with the salinity and the dissolved NaCl concentrations. The occurrence of unusually high 226Ra activities is explained by radium release from adsorption sites with increasing salinity. The inferred spatial variability of 222Rn in the Aral Sea and of 222Rn and 226Ra in the groundwater of the Amu Darya Delta is discussed in the context of our own previous hydrochemical studies in the study sites. Relatively low 222Rn activities in the unconfined GW (1–9.5 Bq/l) indicate the alluvial sediments hosting the GW to be a low-238U(226Ra) substrate. Positive correlations between U and 226Ra, and U and 222Rn are likely related to locally deposited Fe(Mn)OOH precipitates. The 222Rn activity of the GW, however, distinctly exceeds the 222Rn concentration in the Aral Sea (10 mBq/l), in principle, making 222Rn a sensitive tracer for the inflow of GW. The high water volume of the Large Aral Sea and wind induced mixing of its water body, however, hamper the detection of local groundwater inflow. 相似文献
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Integrated geophysics and soil gas profiles as a tool to characterize active faults: the Amer fault example (Pyrenees, NE Spain) 总被引：1，自引：0，他引：1
M. Zarroca R. Linares J. Bach C. Roqué V. Moreno Ll. Font C. Baixeras 《Environmental Earth Sciences》2012,67(3):889-910
The combined use of geophysical and soil gas composition exploration methods allows to rapidly obtain at relative low cost information that might be related to seismic activity conditions. In this study, we carried out geochemical soil gas sampling (222Rn, 220Rn and CO2), electrical resistivity tomography and seismic refraction profiles in two selected zones near the town of Amer in the Spanish Pyrenees, where the presence of recent fractures is evident in the field. Data analysis clearly reveals anomalous values for each gas at specific positions along the electrical imaging transects. Geomorphologic and hydrogeologic data and the integration of geophysical data and soil gas measurements indicate that: (1) endogene gases radon (222Rn) and carbon dioxide (CO2) are released from the meta-sedimentary basement rocks across the main fractured zones with higher permeability values, while lower Cenozoic detrital sedimentary formations act as an impervious boundary; (2) sites with highest radon concentrations (52?kBq?m?3) coincide with the zones in the Amer fault showing more recent geomorphic evidence of activity, and more specifically with those areas covered by thinner surficial formations; (3) the lowest 222Rn values (0.2?C0.4?kBq?m?3) were recorded just on the master active fault plane. This pattern could be explained by a dilution effect resulting from high rates of soil CO2 efflux (267?g?m?2?day?1); (4) soil thoron (220Rn) activity is maximum (143?kBq?m?3) in areas with high surficial fracturing; (5) groundwater pumping may cause important distortions in the natural flow dynamics and in the measured concentrations of gases. The agreement between the different data (geochemical, geophysical, and hydrogeological) and field observations (geology and geomorphology) leads us to propose a preliminary tectonic-gravitational model for the study area. 相似文献
19.
Use of radon isotopes,gamma radiation and dye tracers to study water interactions in a small stream in Brazil 总被引：1，自引：0，他引：1
Vinícius V. M. Ferreira Rubens M. Moreira Zildete Rocha Cláudio J. Chagas Raquel L. M. Fonseca Talita O. Santos Paulo C. H. Rodrigues Maria Angela B. C. Menezes 《Environmental Earth Sciences》2018,77(19):699
In this study, natural (222Rn) and fluorescent (uranin) tracers were used to investigate the interactions between surface and subsurface waters in a small hydrographical basin located in the southeast region of Brazil. Levels of 222Rn were measured in 117 water samples with the use of an alpha solid-state detector. After the identification of the probable discharge sections along the stream, a measurement of the natural flows, upstream and downstream of these sections, was done with the use of a fluorimeter and fluorescent tracers. Also, scanning was done to verify a correlation between the natural gamma radiation and the 222Rn in the areas where its activity was higher. The results showed some sections where the 222Rn activity is more significant and contributed to the growth of the flows along the stream. It was possible to confirm a correlation between the discharge sections and the natural gamma radiation, what can be used as a preliminary approach to finding these sections in scenarios similar to the one studied here. 相似文献