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1.
地下深部流体的来源与演化的研究已成为国际地球化学领域的探索前沿和研究热点之一,中国大陆科学钻探(CCSD)为开展深部流体地球化学研究提供了珍贵的样品,构建了探索地下流体的研究平台。中给出了中国大陆科学钻探(CCSD)主孔He、Ar、N2、O2、H2、CH4、CO2流体地球化学剖面。CCSD主孔CH4浓度的变化与H2浓度的升降没有显相关性;CO2浓度的变化与钻井条件下的氧含量无显相关性;CO2浓度与CH4浓度的关系有三种情况:CO2浓度与CH4浓度不相关、CO2浓度与CH4浓度负相关、或CO2浓度与CH4浓度正相关;氦浓度的增加与CO2和CH4浓度的上升呈现一定的正相关。大气中N2、O2、Ar浓度太高,掩盖了井中N2、O2、Ar气体组分浓度变化,通常情况下N2、O2、Ar浓度变化难以作为深源气体的判据。CCSD流体与KTB流体中氧.氮关系基本一致,氧、氮线性相关(r=0.97),表明这两种气体主要来源于大气。KTB中的CH4与乙烷、N2表现出非常强的线性关系,而在CCSD流体中CH4与乙烷、N2之间不存在线性相关性。两个地区间的流体成因、围岩相互作用机理等方面可能有所不同。在CCSD主孔中,目前已发现存在大量的CO2,及少量CO、CH4、C2H6、C3H8、C4H10和He、N2等气体。已确定300~2000米主孔出现多处来自于地下的气体异常,包括甲烷和C2~C4等烃类气体,一氧化碳与二氧化碳,稀有气体氦。根据流体各组分间相关性研究,可以判定异常中氧主要来源于大气,N2、Ar和CO2有一部分源于大气,一部分来源于地下。在流体显异常时,甲烷等烃类气体、氦、一氧化碳和绝大部分CO2来源于地下。出现显地下流体异常处,在岩石中存在裂隙、晶洞、破裂面、断层;它们作为流体迁移通道或存储空间,可能是流体存在的必要条件。某些CO2和He气异常与碳酸盐和铀矿石等围岩密切相关。  相似文献   

2.
中国大陆科学钻探现场分析与地下流体异常识别   总被引:11,自引:5,他引:6  
对中国大陆科学钻探深孔中泥浆进行脱气,采用质谱仪、气相色谱仪和测氡仪在线测定He、CO2、CH4、H2、N2、O2、Ar、C2H6、C3H8、n-C4H10、H2S、CO、Rn等多种气体。在排除钻井过程、钻具磨损、泥浆性能、仪器波动、气路设计等对气体分析的严重干扰后,可以发现气体异常与岩心和地层裂隙、破裂面及构造破碎带等具有相关性。同时采用高效液相色谱分析泥浆清液,也发现了来源于地下的流体。  相似文献   

3.
二维气相色谱法测定流体包裹体中气相成分   总被引:9,自引:1,他引:9  
建立了双柱、双检测器串联的二维气相色谱测定流体包裹体中气相成分H2、O2、N2、CO、CH4、CO2、H2O、C2H2、C2H6、C3H8的方法。方法经济、易行,灵敏度和精密度高,检出限在10^-4~10^-6(x,摩尔分数),精密度(RSD)小于7%。所获得真实水量与同一缩分样的液相成分离子色谱测定结果相结合,可以得到包裹体溶液中的离子浓度。目前已应用于流体包裹体样品分析,分析结果符合地质研究的要求。  相似文献   

4.
流体包裹体中微量气体组成及其成矿示踪体系研究新进展   总被引:2,自引:0,他引:2  
孙晓明  王敏  薛婷  孙凯 《地学前缘》2004,11(2):471-478
N2 Ar He体系可用以示踪成矿流体及温泉等与火山有关的水流体的来源 ,当体系中He含量低于检出限 ,N2 Ar He体系不能用时 ,CO2 /CH4 N2 /Ar体系可用于识别成矿流体中岩浆水、建造水和大气降水 ,CO2 CH4 H2 体系可以鉴别成矿流体是否发生过沸腾作用以及沸腾是在开放体系还是封闭体系中形成 ,一般开放体系中沸腾有利于成矿。CO2 CH4 C2 H6体系可用于判别岩浆作用是否直接影响成矿或对成矿流体的贡献 ,从而确定热液矿床的成因。CH4 C2 H6 C3 H8体系可用来示踪一些与干酪根热解有关的成矿流体长距离、大规模迁移过程。C2 H6 C3 H8 C6H6体系可用于判定成矿流体的大地构造环境 ,因岛弧与裂谷环境下C2 H6/C3 H8比值有明显差异。以广东长坑 (Au Ag)和嵩溪 (Ag Sb)矿床为例 ,概述了这些体系各自的应用  相似文献   

5.
采用OmniStar型质谱仪在线分析CCSD钻井泥浆中的H2、He、O2、N2、Ar、CH4和CO2等气体组分。采用脱气器、大气平衡仪、气体流量剂、冷冻干燥等样品采集装置,通过合理的设计可以有效地采集到井下气体并且克服大气的污染,除去气体中的水分。根据OmniStar型质谱仪的分析原理及分析能力,建立了可靠的分析方法,其精密度优于2%,准确度高,分析周期为8 s,为科学研究提供了及时、可靠的数据。  相似文献   

6.
中国休眠火山区岩浆来源气体地球化学特征   总被引:6,自引:1,他引:5  
上官志冠  武成智 《岩石学报》2008,24(11):2638-2646
中国休眠火山区岩浆来源气体的最主要成分是CO2,含量占80%~99%;其它气体组分还有CH4、He、H2、N2、Ar、O2、H2S、SO2、CO等,其中CH4和He是CO2以外最值得重视的直接来自地幔岩浆体的气体组分。He的同位素组成(^3He/^4He比值)是休眠火山区最可靠的幔源物质的指示性参数;岩浆来源的CO2和CH4也具有特征的区别于浅源气体的稳定同位素组成(δ^13C值)。长白山火山区近期CO2和CH4的碳同位素分馏监测结果显示,2002年汪清7.2级深震虽然可能引发了深部岩浆的局部扰动,但是它可能并没有产生特别大量的、持续不断的上地幔岩浆物质流的上升迁移。这意味着,长白山天池火山区近期可能没有火山喷发活动的现实危险。  相似文献   

7.
稀有气体与轻稳定同位素气体地球化学的应用研究   总被引:3,自引:0,他引:3  
马锦龙  陶明信 《地质通报》2004,23(4):329-335
稀有气体与CO2、CH4、N2等气体及其同位素的结合研究是近年迅速发展的研究体系。本文综述了2种体系的同位素指标以及CO2/^3He、CH4/^3He、N3/Ar等比值指标在地质领域的研究与应用情况,简述了N2、O2等气体与稀有气体在探索地球大气演化模式方面的概况.  相似文献   

8.
无机成因天然气的地球化学特征   总被引:8,自引:3,他引:8  
甲烷(CH4)等烃类气体自地球深部选出的同时,还伴随有其它气体,如CO2、CO、N2、H2S、H2、He、Ne、Ar等,统称为无机成因天然气.无机成因天然气与生物成因天然气在地球化学特征上存在显著的差异,主要表现在化学成分和同住素组成特征.无机成因CH4的干燥系数较大,δ13C1值几乎都大于-25‰,且CH4及其同系物碳同住素组成的分布随碳数的增大而变轻(反序);无机成因CO2碳同住素较重;稀有气体中w(3He)/w(4He)值较低等.这些特征是判别无机成因天然气的重要地球化学指标.  相似文献   

9.
将野外装入解吸罐中的煤芯样,用真空脱气装置脱气,脱出的气体通过GC4008B气相色谱仪进行组份浓度测定,记录的数据经A5000气相色谱工作站数据处理软件处理。从而快速、准确地测定出CO、CO2、CH4、C2H4、C2H6、C3H8以及重烃等气体成分的含量。用于大批量实际样品测定,符合质量管理的要求。  相似文献   

10.
地气法是较新发展起来的地球化学勘探方法,地气是指从地球内部上升至地球表层的气体,主要包括H2O,CO2,H2S,NH3,H2,N2,CH4,He,Rn,Ar。研究证实,地气在经过矿体时可以将含有相关元素的物质携带并迁移至地表造成地球化学异常。据此,可通过采集地气样品,分析其中的元素成分及含量,推测地下的物  相似文献   

11.
The spatio-temporal variations of soil gas in the seismic fault zone produced by the 12 May 2008 Wenchuan Ms 8.0 earthquake were investigated based on the field measurements of soil gas concentrations after the main shock. Concentrations of He, H2, CO2, CH4, O2, N2, Rn, and Hg in soil gas were measured in the field at eight short profiles across the seismic rupture zone in June and December 2008 and July 2009. Soil-gas concentrations of more than 800 sampling sites were obtained. The data showed that the magnitudes of the He and H2 anomalies of three surveys declined significantly with decreasing strength of the aftershocks with time. The maximum concentrations of He and H2 (40 and 279.4 ppm, respectively) were found in three replicates at the south part of the rupture zone close to the epicenter. The spatio-temporal variations of CO2, Rn, and Hg concentrations differed obviously between the north and south parts of the fault zone. The maximum He and H2 concentrations in Jun 2008 occurred near the parts of the rupture zone where vertical displacements were larger. The anomalies of He, H2, CO2, Rn, and Hg concentrations could be related to the variation in the regional stress field and the aftershock activity.  相似文献   

12.
Chemical and isotopic compositions have been measured for N2-He-rich bubbling gases discharging from hot springs in the Hainan Island, Southern China. Observed 3He/4He ratios (0.1–1.3 RA) indicate the occurrence of a mantle component throughout the island, which has been highly diluted by a crustal radiogenic 4He component. The occurrence of mantle-derived helium is high in the northern island (12%–16% of total He) and gradually decreases towards southern coast (1%–3% of total He). Such a distribution pattern is most likely controlled by the Pleocene-Quaternary volcanic activities in the northern island and groundwater circulation along the deep major faults. The 40Ar/36Ar and N2/Ar ratios suggest that N2 and Ar of the hot spring gases are mostly meteoric. Although δ13C values of CO2 (–20‰ to –27‰) with low concentrations are consistent with the biogenic origin, the combination of 3He/4He and d13CCO2 suggests a two end-member mixing of mantle and crustal components with CO2/3He ratios of 2×109 and 8×1011, respectively. However, the low CO2/3He ratios (1–22×106) can not be ascribed in terms of the simple mixing but has to be explained by the addition of radiogenic 4He and loss of CO2 by calcite precipitation in the hydrothermal system, which is most likely controlled by the degree of gas-water-rock interaction.  相似文献   

13.
New volatile data (CO2, H2O, He, Ne, and Ar) are presented for 24 submarine basaltic glasses from the Kolbeinsey Ridge, Tjörnes Fracture Zone and Mohns Ridge, North Atlantic. Low CO2 and He contents indicate that magmas were strongly outgassed with the extent of degassing increasing toward the south, as expected from shallower ridge depths. Ne and Ar are significantly more abundant in the southernmost glasses than predicted for degassed melt. The strong atmospheric isotopic signal associated with this excess Ne and Ar suggests syn- or posteruptive contamination by air. Degassing, by itself, cannot generate the large variations in δ13C values of dissolved CO2 or coupled CO2-Ar variations. This suggests that δ13C values were also affected by some other processes, most probably melt-crust interaction. Modelling indicates that degassing had a negligible influence on water owing to its higher solubility in basaltic melt than the other volatiles. Low H2O contents in the glasses reflect melting of a mantle source that is not water-rich relative to the source of N-MORB.Before eruption, Kolbeinsey Ridge melts contained ∼400 ppm CO2 with δ13C of −6‰, 0.1 to 0.35 wt.% H2O, 3He/4He ∼11 RA, and CO2/3He of ∼2 × 109. We model restored volatile characteristics and find homogeneous compositions in the source of Kolbeinsey Ridge magmas. Relative to the MORB-source, He and Ne are mildly fractionated while the 40Ar/36Ar may be low. The 3He/4He ratios in Tjörnes Fracture Zone glasses are slightly higher (13.6 RA) than on Kolbeinsey Ridge, suggesting a greater contribution of Icelandic mantle from the south, but the lack of 3He/4He variation along the Kolbeinsey Ridge is inconsistent with active dispersal of Icelandic mantle beyond the Tjörnes Fracture Zone.  相似文献   

14.
Orthopyroxene, clinopyroxene, and olivine from a metasomatized mantle xenolith of garnet lherzolite in alkaline rocks at the Jetty Oasis, East Antarctica, contain numerous carbon dioxide-dominated composite melt-fluid and fluidized sulfide-silicate (±carbonate) inclusions. Although the maximum pressure under which the inclusions were captured by rock-forming minerals was evaluated at 13 kbar, its actual value should have been much higher, judging by the fact that the inclusions have lost part of their material (decrepitated) when the xenolith was brought to the surface. Two major fluid populations are distinguished. The fluids entrapped during the earlier episode have a more complicated composition. Dominated by CO2, these fluids contain much N2 (0.1–0.2 mole fractions), H2S, and perhaps, also H2O and are hosted by sulfide-silicate (±carbonate) inclusions produced by liquid immiscibility. As these inclusions evolved, they enriched in CO2 and depleted in H2S and N2. Although the concentrations of N2, H2S, and H2O were generally relatively low, these components played an important role in mantle metasomatism, as is reflected in the geochemistry of the derived magmas. The fluids of the younger episode (pressures lower than 7 kbar) are notably richer not only in CO2 but also in H2O (up to the appearance of inclusions with a liquid aqueous phase and the formation of CO2 gas hydrate when cooled in a cryometric stage by liquid N2). The effect of fluids on the mantle source in two discrete episodes is also confirmed by isotopic-geochemical data. Isotopic data on gases obtained immediately from fluid inclusions in minerals by the stepwise crushing technique provide evidence of the evolution of elemental and isotopic ratios of the gases in the course of the metasomatic processes. The high-pressure fluid inclusions of the earlier episode have low C/N2, C/Ar, and N2/Ar ratios, isotopically heavy N2, and somewhat elevated (to 530) 40Ar/36Ar ratios. The younger fluids typically have higher (by two to three orders of magnitude) C/N2 and C/Ar ratios, lower δ13C of CO2, and N2/Ar and 40Ar/36Ar ratios close to the atmospheric values. The nitrogen and argon isotopic compositions and elemental ratios suggest that the younger fluids could have been produced by two-component mixing in the mantle-atmosphere system. Comprehensive analysis of the data and in particular the 40Ar/36Ar ratios, which are atypical of the mantle, and an increase in the H2O concentration, suggests a subduction-related nature of the fluids.  相似文献   

15.
Variations of He gas concentration are widely applied in studies devoted to the location of faults and to monitor seismic activities. Up to now, its migration mechanism in soil is not fully understood. A systematic soil gas survey across an active fault in NW Taiwan provides the opportunity to closely examine the mechanism of He migration in the fault zone. Significant spatial and temporal correlations observed between soil N2 and He gas support the hypothesis that N2 is the probable carrier gas for He emission in the studied area. Based on N2/Ar ratios and N2 isotopic results, the excess soil N2 in this study is considered to be largely derived from ancient atmospheric air which was dissolved in groundwater. Furthermore, observations rule out the possibility of CO2 being the dominant carrier gas for He in the studied area based on the C and He isotopic compositions and the relationship between concentrations of these gases. At least two soil gas sources, A and B, can be identified in the studied area. Source A is an abiogenic gas source characterized by excess N2 and He, and very low O2 and CO2 content. Source B, on the other hand, is a mixture of biogenic gas and atmospheric air. The development of the fault system is an important factor affecting the degree of mixture between sources A and B. Therefore, variations of soil gas composition, in particular those derived from source A, could be a useful proxy for tracing faults in the area.  相似文献   

16.
A new microscope vacuum heating stage and gas analyzer has been developed for measurement of H2O, CO2, SO2, and noncondensable gas (H2, CO, N2, Ar, CH4, etc.) evolved from samples, particularly natural glass, at temperatures up to 1280°C. The gas evolved upon heating to 1280δC is collected in a liquid nitrogen cold trap. Gas components are identified by the characteristic vapor pressure and temperature ranges over which solid and vapor are in equilibrium during sublimation of individual components. The masses of CO2, SO2, and H2O derived from samples and blanks are calculated using the ideal gas law, the molecular weights of the components, and the gauge constant (i.e. the ratio of the number of moles of a gas to its partial pressure in the constant volume). Results obtained by repeated determinations of H2O, CO2, and SO2 evolved from a submarine basaltic glass from Kilauea volcano, Hawaii, (average sample mass = 3 × 10?3 g) gave probable errors for the determinations of H2O (0.23%), CO2 (0.025%), and S (0.071%) equal to 4, 10, and 8% respectively, of the concentrations. Determinations of H2O in smaller samples of H2O-poor basaltic pumice show a linear proportionality (0.063%) between the measured H2O and the sample mass over the range 0.1 × 10?6 to 1.7 × 10?6 g H2O. Comparisons of H2O determinations by this technique with those obtained by Penfield, gas chromatic, microcoulometric, and vacuum fusion techniques used elsewhere show reasonably good agreement. Determinations of SO2 by this technique agree reasonably well X-ray fluorescence and electron microprobe determinations of sulfur. Determinations of CO2 by the present technique are reproducible but cannot be compared directly to measurements made in other labs because of differences in samples analyzed. The principle advantages of this analytical technique are the very small sample required, the simultaneous determination of H2O, CO2, SO2 and noncondensable gas, the avoidance of calibration procedures dependent on chemical standards, and the visual observations that can be made during sample outgassing.  相似文献   

17.
The chemical composition of the gases emitted from a hornito close to the active lava lake of Erta'Ale, Ethiopia, as derived from chemical analyses on 18 samples collected on 23 January 1974, was found to be (in mol-%): H2O: 79.4, CO2: 10.4, total S: 7.36, HCl: 0.42, H2: 1.49, N2: 0.18, Ar: 0.001, CO: 0.46, and COS: 0.009. Thermodynamic considerations, based on the equilibria CO2 + H2 ? CO + H2O and CO2 + 3H2 + SO2 ? COS + 3H2O show that the analytical values represent the equilibrium composition of a gas mixture at the measured temperature of around 1130°C under close to the surface pressure conditions. Comparison of the Erta'Ale gas emissions with those from other volcanoes suggests a close similarity in their chemical composition. This similarity is considered to be due to common processes governing the release of gaseous species from a magma.  相似文献   

18.
In the Northern Jiangsu basin there are high pure CO2 gas pools, low condensed oil-containing CO2 gas pools, high condensed oil-containing CO2 gas pools and He-containing natural gas pools, with the δ13Cco2 (PDB) values ranging from -2.87‰ to -6.50‰, 3He/4He 3.71×10-6 to 6.42×10-6, R/Ra 2.64 to 4.5, 40Ar/36Ar 705 to 734, belonging to typical mantle source inorganic gas pools which are related to young magmatic activity. The gas layers occur in two major reservoir-caprock systems, the terrestrial Meso-Cenozoic clastic rock system and the marine Meso-Palaeozoic carbonate rock-clastic rock system. Controlled by the difference in the scale of traps in the two reservoir-caprock systems, large and medium-scale inorganic gas pools are formed in the marine Meso-Palaeozoic Group and only small ones are formed in the terrestrial Meso-Cenozoic strata. Inorganic gas pools in this basin are distributed along the two deep lithospheric faults on the west and south boundaries of the basin. Gas pools are developed  相似文献   

19.
张体强  胡树国  韩桥 《岩矿测试》2014,33(6):775-781
超高纯气体在工业生产中有非常重要的地位,如半导体工业中电子气的质量直接影响半导体器件的性能,百万分之几的微量杂质气体便可导致集成电路中元件存储信息量的减少。越来越高的气体纯度要求对分析方法及仪器的灵敏度提出了很大的挑战。大气压电离质谱(APIMS)由于可以在大气压条件下对杂质进行电离,并伴随高效的电离方式,因此具有极高的灵敏度,成为超高纯气体杂质分析中极为有效的技术手段,特别适合检测10-9 mol/mol甚至10-12 mol/mol浓度量级的气体杂质。APIMS采用电晕放电及63Ni两种电离源,通常以电晕放电电离源为主,质量分析器常采用四极杆,同时为适应超高纯气体分析,APIMS配备了气体进样系统及可将标准气体稀释产生校正气体的稀释系统。APIMS对杂质检测的灵敏度与杂质的电离方式密切相关,电荷传递是杂质电离最主要的一种方式,适用于电离能相差较大的底气与杂质,常见的N2、Ar由于电离能较高,其中的大部分杂质均可依靠该方式测定;质子转移反应的应用通常与H2有关,常用于H2中杂质的测定,也可以通过添加H2的方法促进对Ar中N2杂质的检测;运用形成团簇离子的反应尽管较少,但亦有报道,通过监测团簇离子O2+·H2O,可提高O2中杂质H2O的检测灵敏度。依据不同的电离反应,可以设计对不同杂质的测定方式,实现对痕量、超痕量杂质的检测。APIMS检测灵敏度通常比电子轰击电离质谱(EI/MS)高104~106倍,因此目前依然是超高纯气体分析中不可替代的仪器方法,但在某些方面如对有腐蚀性电子特气的分析,方法灵敏度有待提高。  相似文献   

20.
The molar ratios of atmospheric gases change during dissolution in water due to differences in their relative solubilities. We exploited this characteristic to develop a tool to clarify the origin of ice formations in permafrost regions. Extracted from ice, molar gas ratios can distinguish buried glacier ice from intrasedimental ground ice formed by freezing groundwaters. An extraction line was built to isolate gases from ice by melting and trapping with liquid He, followed by analysis of N2, O2,, Ar, 18OO2 and 15NN2, by continuous flow mass spectrometry. The method was tested using glacier ice, aufeis ice (river icing) and intrasedimental ground ice from sites in the Canadian Arctic. O2/Ar and N2/Ar ratios clearly distinguish between atmospheric gas in glacial ice and gases from intrasedimental ground ice, which are exsolved from freezing water. δ15NN2 and δ18OO2 in glacier ice, aufeis ice and intrasedimental ground ice do not show clear distinguishing trends as they are affected by various physical processes during formation such as gravitational settling, excess air addition, mixing with snow pack, and respiration.  相似文献   

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