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91.
为了对大同盆地地下水中砷、氟、碘等的分布和成因进行分析,开展地下水质量区划,依据地下水污染调查取得的最新系列测试数据,结合以往水文地质和水文地球化学研究成果,编制大同盆地浅层和中深层地下水砷含量、氟含量、碘含量等水化学特征分布图,以直观反映大同盆地地下水高砷、高氟、高碘区的空间分布规律; 通过分析pH值、硫酸根含量、硝酸根含量、铁含量、锰含量与砷的关系,探讨高砷水的形成原因; 根据pH值、钙离子、重碳酸氢根离子与氟的关系,分析氟超标原因; 指出高碘区与高氟区分布的相似性和成因的相似性。研究结果表明,盆地周边高砷、高氟岩层是地下水砷、氟的原生来源,特定的河湖相沉积环境则为砷、碘的富集提供了原生地质条件; 北部地区氟增高与地下水位下降致使黏性土中的氟离子进入含水层有关,中部地区高氟与土壤盐渍化有关; 中部富含淤泥质黏土的湖相地层是碘富集的原生地质因素,冲积洼地地下水径流条件滞缓是碘富集的水动力因素; 干旱气候条件下强烈的蒸发浓缩作用亦是高氟、高碘地下水形成的重要因素。依据砷、氟、碘、硝酸盐、亚硝酸盐、总含盐量(total dissolved salt,TDS)、总硬度、氨氮等单组分含量分布,利用GIS空间分析功能,进行了大同盆地浅层和中深层地下水质量区划,可为当地地下水开发利用提供地学依据。 相似文献
92.
93.
Paul W.O. Hoskin 《Geostandards and Geoanalytical Research》1999,23(1):69-76
The fluorine concentration in NIST SRM 610 was determined by SIMS to be 295 16 μg g−1 (5.40% relative standard deviation). Accuracy of the measurement was determined from a calibration involving the synthesis of glass calibration samples doped with varying concentrations of fluorine and characterized by electron microprobe analysis and SIMS. The calibration was accurate to about 5%. Multiple analyses of the calibration samples and SRM 610 in three different analytical sessions combine to produce a low relative standard deviation of the mean (0.23% RSD) in the mean fluorine value for SRM 610. Analytical uncertainty in the fluorine value was 5.40% (RSD), originating from a combination of calibration and ion counting uncertainties as determined from multiple analyses. Evaluation of the SIMS technique using the new fluorine value in SRM 610 shows that this element can be determined with a precision and accuracy superior to that of EPMA. Measurements of fluorine in igneous and hydrothermal zircon suggest that F-ligands may have been responsible for Zr transportation in hydrothermal fluids also responsible for W-Au mineralisation. Other applications for low-level fluorine determinations may include melt inclusions and nominally anhydrous mineral phases, particularly mantle phases. 相似文献
94.
南大洋磷虾富氟机制Ⅰ.氟的化学赋存形态研究 总被引:5,自引:0,他引:5
通过对南极大磷虾(Euphausia superba)进行活体生长培养,对其不同部位及生长过程中不同阶段样品进行了氟的形态赋存分析,研究表明磷虾中90%的氟集中在甲壳中,在其生长脱壳周期中,甲壳和肌肉中的氟含量呈相对应的周期性变化,在脱壳后最初新甲壳和肌肉中氟含量较低,通过生物主动吸收,海水中氟迅速被有效吸收和转化,而磷虾所吸收的氟最终又以存在于旧甲壳中随磷虾脱壳而丢失。在磷虾的生长周期中甲壳和肌肉中的不同化学形态氟赋存变化充分证明了这一点。最后提出了磷虾富氟机制的一个过程模式。 相似文献
95.
96.
Fluorine and chlorine behaviour during progressive dehydration melting: Consequences for granite geochemistry and metallogeny 下载免费PDF全文
Dehydration melting of biotite is the main control on crustal differentiation in the mid to lower continental crust because this reaction produces the most voluminous and most mobile granitic melts. Biotite breaks down over a broad temperature interval, so the partitioning behaviour of elements between biotite and melt is likely to vary. It has been hypothesized that fluorine may stabilize biotite to higher melting temperatures because biotite is typically F‐rich in ultra‐high temperature (UHT) metamorphic rocks. If true, F would be an important influence on crustal differentiation because not only would it broaden the temperature range of melting but also elevated F concentration decreases melt viscosity. Furthermore, ligand partitioning between biotite and melt may be an important influence on the metallogeny of magmas. This study used electron microprobe analysis of biotite in rocks from the Ballachulish and Rogaland metamorphic aureoles to investigate the concentration of F and Cl in biotite heated to 600–1,000°C. Results show a broad increase in biotite F content (up to 5.04% F) with temperature until 850–920°C, beyond which F content decreases (<2.5% F). Chlorine concentrations in biotite are consistently lower (<1% Cl), and show a progressive decrease after the onset of partial melting. It was found that Mg content, and the processes that control Mg distribution, are most strongly correlated with F and Cl concentration in biotite. Calculations based on these results indicate that F‐enriched biotite could be a significant source of F for continental crust‐derived melts. Generation of a hot, F‐rich melt at UHT conditions could be important for transporting lower crustal metals to the upper crust. 相似文献
97.
胡卫忠 《地质灾害与环境保护》1995,6(4):21-28
南疆地区的主要地方病有地甲病,克汀病,地氟病等,产生上述疾病的病因主要地下水,地表水的碘含量偏低或偏高和水含氟量超标,这些微量元素丰度偏离了人体生存标准,导致人体产生病变所致,为了保障未成年人的正常发育和广大农牧民的身体健康,本文提出了首先要改水防治,同时配合药物治疗的防治对策。 相似文献
98.
An electron probe and chemical study of bulk phosphorite samples and separated constituents from various Negev deposits was carried out together with XRD, FTIR spectroscopy and textural analysis. The results allow a better understanding of the distribution of fluorine in these Upper Cretaceous phosphorite sequences and shed light on variations in the composition of the carbonate fluorapatite (CFA) phase during phosphogenesis. Two facies are recognized: (1) a pristine, microbially generated phosphorite facies; (2) a recycled, peloidal and biodetrital facies. Fluorine distribution in the Negev phosphorites is facies controlled: F/P2O5 is much lower in the pristine facies (0·090–0·107) than in the recycled facies (0·107–0·120). In addition, F/P2O5 varies considerably between the various constituents of the phosphate fraction; F‐poor francolites (F/P2O5 as low as 0·080) co‐exist with F‐rich francolites (F/P2O5 as high as 0·135) in the same phosphorite bulk sample. A lower F/P2O5 in francolite is associated with higher Cd and Zn concentrations in the phosphorite, an increase in Fe‐rich smectites in the clay fraction and the presence of structural OH in the francolite. The lower F/P2O5 ratios in the pristine facies are attributed to high organic deposition rates during the formation of these matted sediments, leading to rapid burial of the in situ‐forming CFA. This is possibly coupled with diffusion of F from sea water into bottom sediments being hampered by microbial mat coatings. These conditions resulted in O2‐depleted porefluids, inducing the precipitation of Cd‐rich Zn sulphides and the formation of Fe‐rich smectites. F‐enrichment probably takes place when the earlier formed F‐poor ‘primary’ CFA is relocated close to the sea floor and bathed with interstitial sea water solutions of higher F concentrations. Oxidation and removal of the sulphide‐bound Cd and Zn apparently occurred together with enrichment in F of the francolite. Combining chemical data with XRD and FTIR results suggests a multistage growth for the Negev phosphate constituents in shifting formational sites and porefluids of varying F concentrations. This multiphase growth is reflected in the patchy distribution of F in the Negev constituents and might explain the inverse correlation between mean CO2/F and F/P2O5 ratios of the analysed phosphorites in the two facies. It also suggests that CFA (or an amorphous precursor) initially formed with some OH groups in the apatite structure, which were subsequently substituted by F ions in recycled francolite through re‐equilibration with porefluids of higher F concentrations. 相似文献
99.
R. Zander M. R. Gunson C. B. Farmer C. P. Rinsland F. W. Irion E. Mahieu 《Journal of Atmospheric Chemistry》1992,15(2):171-186
The set of high-resolution infrared solar observations made with the Atmospheric Trace Molecule Spectroscopy (ATMOS)-Fourier transform spectrometer from onboard Spacelab 3 (30 April-1 May 1985) has been used to evaluate the total budgets of the odd chlorine and fluorine chemical families in the stratosphere. These budgets are based on volume mixing ratio profiles measured for HCl, HF, CH3Cl, ClONO2, CCl4, CCl2F2, CCl3F, CHClF2, CF4, COF2, and SF6 near 30° north latitude. When including realistic concentrations for species not measured by ATMOS, i.e., the source gases CH3CCl3 and C2F3Cl3 below 25 km, and the reservoirs ClO, HOCl and COFCl between 15 and 40 km (five gases actually measured by other techniques), the 30° N zonal 1985 mean total mixing ratio of chlorine, Cl, was found to be equal to (2.58±0.10) ppbv (parts per billion by volume) throughout the stratosphere, with no significant decrease near the stratopause. The results for total fluorine indicate a slight, but steady, decrease of its volume mixing ratio with increasing altitude, around a mean stratospheric value of (1.15±0.12) ppbv. Both uncertainties correspond to one standard deviation. These mean springtime 1985 stratospheric budgets are commensurate with values reported for the tropospheric Cl and F concentrations in the early 1980s, when allowance is made for the growth rates of their source gases at the ground and the time required for tropospheric air to be transported into the stratosphere. The results are discussed with emphasis on conservation of fluorine and chlorine and the partitioning among source, sink, and reservoir gases throughout the stratosphere. 相似文献
100.
《中国地质大学学报(英文版)》1990,(1)
This paper approaches the transportation of fluorine in the groundwater ofepigene Quarternary aquifer by calculation and laboratory studies.The conclusionthat the enrichment and saturation abilities of fluorite are related to the transpor-tation of fluorine in groundwater is reached.They would be conducive to findingthe cause of regional fluorine distribution in the groundwater of North China. 相似文献