共查询到20条相似文献，搜索用时 46 毫秒
1.
辽东吉南硼矿是中国著名的大型硼矿，为了研究矿石与容矿岩石的关系，作者就以研究硼矿石的特征作为切入点。通过矿石的自然形态、矿石结构、矿石构造、矿石化学成分和矿化类型等的分析，揭示出矿石的形成与容矿岩石的地质特征有密切关系，主要体现在：①矿石与容矿岩石的矿物都是富镁质矿物；②矿石对容矿岩石具有交代继承的结构构造；③矿石的稀土元素特征与容矿岩石具相似性的配分模式。从而得出辽东吉南硼矿的容矿岩石不仅为硼矿的形成提供有利的储存空间，而且对硼矿的形成有决定性的岩控作用。 相似文献
2.
The geochemical cycle of boron: Constraints from boron isotope partitioning experiments between mica and fluid 总被引：8，自引：0，他引：8
Bernd Wunder Anette Meixner Rolf L. Romer Richard Wirth Wilhelm Heinrich 《Lithos》2005,84(3-4):206-216
The fractionation of boron isotopes between synthetic boromuscovite and fluid was experimentally determined at 3.0 GPa/500 °C and 3.0 GPa/700 °C. For near-neutral fluids Δ11B(mica-fluid) = δ11B(mica) − δ11B(fluid) is − 10.9 ± 1.3‰ at 500 °C, and − 6.5 ± 0.4‰ at 700 °C. This supports earlier assumptions that the main fractionation effect is due to the change from trigonal coordination of boron in neutral fluids to tetrahedrally coordinated boron in micas, clays and melts. The T-dependence of this effect is approximated by the equation Δ11B(mica,clay,melt–neutral fluid) = − 10.69 · (1000/T [K]) + 3.88; R2 = 0.992, valid from 25 °C for fluid–clay up to about 1000 °C for fluid–silicate melt. Experiments at 0.4 GPa that used strongly basic fluids produced significantly lower fractionations with Δ11B(mica–fluid) of − 7.4 ± 1.0‰ at 400 °C, and − 4.8 ± 1.0‰ at 500 °C, showing the reduced fractionation effect when large amounts of boron in basic fluids are tetrahedrally coordinated. Field studies have shown that boron concentrations and 11B/10B-ratios in volcanic arcs systematically decrease across the arc with increasing distance from the trench, thus reflecting the thermal structure of the subducting slab. Our experiments show that the boron isotopic signature in volcanic arcs probably results from continuous dehydration of micas along a distinct P–T range. Continuous slab dehydration and boron transport via fluid into the mantle wedge is responsible for the boron isotopic signature in volcanic arcs. 相似文献
3.
Yun LIU Mao TANG John Tossell 《中国地球化学学报》2006,25(B08):16-17
larger value of 1.033 instead of 1.0194. 相似文献
4.
电气石是一种以含硼为特征的硅酸盐矿物,矿物中硼含量在2.78%~3.4%之间,但电气石中的硼被束缚在稳定的晶体结构中难以溶出而被植物吸收,从而影响电气石中硼在农业上的应用。本文通过一系列实验与检测分析,对电气石中硼的溶出机制进行了研究,发现＂高温煅烧十活化剂＂相结合的方法能有效地将电气石中硼的溶出,并初步选定Na2CO3为理想的活化剂,为开发电气石硼肥奠定了理论基础。 相似文献
5.
为确定元素 B 掺入进珊瑚的形式、B(OH)与 B(OH)3间的分馏系数及珊瑚中微量元素对硼同位素?4组成的影响,对北海涠洲岛、海南三亚和雷州半岛灯楼角三地活体珊瑚的 Mg、Sr、Na、Ca、B 浓度及硼同位素组成(δ11Bcoral)进行了测定.结果表明,涠洲岛、三亚和灯楼角三地珊瑚的 Mg、Sr、Na 和 Ca 浓度平均值分别为40.1 mmol/L、86.1 mmol/L、449 mmol/L 和12.1 mol/L.珊瑚中 B 浓度的变化范围为4.4~8.4 mmol/L,平均值为5.9 mmol/L.Ca、Sr 在珊瑚中明显富集,而 Mg 在珊瑚中贫化.珊瑚 B 浓度的变化主要反映了珊瑚生长时海水 pH 值的变化.δ11Bcoral 的变化范围为22.8‰~27.9‰,平均为25.2‰.除与 B 浓度呈弱正相关关系外,δ11Bcoral 与其他四种元素不相关.应用珊瑚硼同位素组成恢复古海水 pH 值时选择同属种珊瑚和判别是否有 Mg(OH)2的存在是必要的.涠洲岛、灯楼角和三亚三地珊瑚与海水间的硼同位素分馏系数αcoral-sw 分别为0.9839、0.9847和0.9850.计算得到的珊瑚与海水 B(OH)3间的分馏系数αcoral-3的变化范围为0.9772~0.9800,平均值为0.9788.该新的α4-3值是准确的,可以用来反演古海水 pH 值.αcoral-sw 和αcoral-3随pH 值的升高分别呈现出增大和减小的变化趋势.珊瑚的平均δ11Bcoral 位于理论计算的δ11B4和δ11B3曲线之间,而且都低于原始合成海水的δ11B.这些都表明 B 以 B(OH)3和B(OH)两种形式以变化的比例同时掺入进?4珊瑚,并以B(OH)优先掺入为主.计算得到有0.1%~5.5%(平均值为2.2%)的 B(OH)3掺入进珊瑚中.由于?4 B(OH)3同时掺入进生物碳酸盐,δ11Bcarb=δ11B4的假设不能成立,由所测生物碳酸盐δ11Bcarb 值计算的海水 pH值将产生误差,使δ11B-pH 技术变得更为复杂.通过无机碳酸盐沉积或有孔虫或珊瑚的养殖实验(或者野外观测实验)建立用于重建古海水 pH 值的δ11Bcarb-pH 经验方程是今后的一项重要任务. 相似文献
6.
硼的地球化学性质及其在俯冲带的循环与成矿初探 总被引：2，自引：1，他引：1
硼是广泛应用于化工、农业、材料科学及核工业领域的重要元素。硼与氢的核聚变反应是未来具备运用潜力的清洁能源。硼作为典型的亲石元素,是高度不相容元素。硼元素容易富集于蚀变洋壳及蛇纹石化地幔橄榄岩中。而在板块俯冲过程中,由于硼具有强的流体活动性,会优先赋存于流体中。因此,当蛇纹石化的大洋岩石圈及覆于其上的沉积物在俯冲过程中发生脱水,这使得弧前地幔楔发生大规模的蛇纹石化。此时大量硼元素很可能随俯冲流体释放并封存于弧前地幔楔中。目前已发现的超大型硼矿床主要位于聚合型板块边缘,尤其土耳其拥有世界上最大的硼酸盐储量。我们推测这些矿床的形成基础条件之一可能与弧前高度蛇纹石化的地幔楔有关。尤其是在洋 陆俯冲环境,弧前蛇纹岩或蛇绿混杂岩首先通过俯冲侵蚀再循环到火山弧岩浆中,使得岩浆更富集硼。随后弧火山喷发大量富硼的火山岩、岩浆热液及水气。在岩浆冷却过程中,硼元素析出、沉淀于火山表面,并伴随风化、侵蚀过程汇聚至碰撞造山带的封闭湖盆之中。此外,干冷的气候条件下也进一步促进了硼的成矿。我国具有形成大型、超大型硼矿的地质条件,应加大研究及探勘力度,并适当购买硼作为战略储备。 相似文献
7.
本文介绍了分光光度法测定硼的分析方法,盐酸介质中,硼与甲亚胺-H生成可溶性黄色络合物,用饱和Ba CO3溶液沉淀去除其干扰,于420.0 nm进行比色。方法的检出限为29μg/g,结果满足国家标准物质和实际样品分析测试要求,达到了国家标准。 相似文献
8.
电气石硼肥制作技术的试验研究 总被引：1，自引：0，他引：1
硼元素是农作物生长所需的七种微量元素之一。目前给土壤补充硼元素的主要方式是施硼肥(来自硼砂矿),随着硼砂矿资源的日益减少,寻找硼替代资源日渐紧迫。笔者认为,电气石是可替代硼砂的主要矿物之一。利用电气石中硼的关键是将电气石中的硼变为可溶性硼。实验表明,高温焙烧法对电气石中硼的溶出非常有限,而用添加HF等助剂的化学法将电气石中的硼活化溶出的方法,效果较好。因此,可通过化学法先将电气石中的硼元素溶出,然后再加入部分电气石及辅料来制作电气石硼肥。 相似文献
9.
F. Ranjbar M. Jalali 《International Journal of Environmental Science and Technology》2014,11(5):1317-1326
This study aimed to evaluate boron (B) adsorption and the capacity of a surface complexation model for simulating this process in calcareous soils. Ten surface soils were collected from different land use areas in Hamedan, Western Iran, to characterize B sorption by soils. The mean B adsorbed by the sample soils varied from 8.9 to 32.8 %. Two empirical models including linear and Freundlich equations fitted well to the experimental data. The linear distribution (K d) values varied from 1.32 to 6.86 L kg?1, while the parameters of Freundlich equation including n and K Fr ranged from 1.16 to 1.33 and 3.31–16.81, respectively. The comparison of two empirical models indicated that B adsorption followed a nonlinear pattern. The soil organic matter had positive correlations with Freundlich and linear distribution coefficients. However, empirical models were not suitable for explaining the mechanism of B adsorption, so a surface complexation model was used to simulate and predict the B adsorption process. B adsorption modeling was conducted using Visual MINTEQ and PHREEQC, based on the assemblage of major surface components (hydrous ferric oxides, aluminum hydroxides, calcium carbonate, and humic acids). B adsorption was successfully modeled by surface complexation. The significant contribution of organic matter to B complexes was resulted from both experimental data and mechanistic modeling. 相似文献
10.
11.
《International Geology Review》2012,54(1):11-16
The reaction of minerals of boron to neutron radiation; is such that neutron logging of boreholes provides a geophysical tool with which to seek their ores.. It is based on the reaction of the isotope of boron B1O with a thermal neutron: B10 + n9 → Li7 + α. A sonde designed specifically for the purpose has been tested. Until they are generally available, another type can easily he modified for neutron logging of boron. Different procedures and interpretation permit initial identification, preliminary assay, and estimates of reserves. —M. Russell 相似文献
12.
《Applied Geochemistry》2001,16(3):317-322
Significant B isotope abundance variations were found for a variety of Coffea arabica beans from a number of coffee-growing regions around the world. This may be attributed to the influence of local sources of B (including soil, water and fertilizer) each having a characteristic B isotope abundance ratio of its own. The results of this preliminary study indicate that B isotope abundance data can be used to study the biogeochemical cycle of B, an important micronutrient. In addition, the isotopic data can be employed in quality assurance programs of commercial coffee as the quality depends to a large extent on the genetic and geographic origin of the coffee. 相似文献
13.
ZHANG Yanling XIAO Yingkai MA Yunqi ZHUGE Qin LIU Zhiqi HE Maoyong LUO Chongguang MA Haizhou 《中国地球化学学报》2013,32(2):203-211
The procedures of sample preparation for isotopic determination of boron in clay sediments is very cumbersome, by far, there haven’t been relevant reports on that. In order to establish an effective method for sample preparation, a series of experiments were carried out. In this paper, boron in clay sediments was extracted with HCl solution and purified by two-step ion exchange method. Extracted HCl solution should be adjusted to alkalescency before passing through the Amberlite IRA 743 resin column due to the fact that Amberlite IRA 743 resin absorbs boron only from alkalescent solution. However, a mass of hydroxides of Al and Fe will be precipitated when the extracted HCl solution becomes alkalescent. Hydroxides of Al and Fe have a strong adsorption capacity for boron, which can cause boron isotope fractionation. To treat precipitated hydroxides of Al and Fe, four procedures, namely direct ion exchange (DRIE), decationizing ion exchange (DCIE), once sedimentation ion exchange (OSIE) and repeated sedimentation ion exchange (RSIE) were used and assessed. The influences of the four procedures on separation and extraction and isotopic composition of boron in experimental solutions and clay sediments were also discussed. According to the results, the DRIE, DCIE and OSIE are improper. The result of sample determination indicates that when extracting boron via RSIE, with the increase of precipitation times, there’s an obvious decrease in boron content in the precipitated hydroxides while a sharp increase in recovery of boron and it is favorable for weakening the influence of boron isotope fractionation. But the process of RSIE is time consuming and it may introduce boron. It needs further research to establish a more effective sample preparation method for isotopic deter- mination of boron in clay sediments. 相似文献
14.
Analyses of meteorites for B abundances have shown that many chondrites are contaminated with terrestrial B, producing erroneously high meteoritic abundances of this element. Boron concentrations in freshly prepared interior samples are significantly lower than they are in samples with unknown or unspecified terrestrial histories. An estimate of the cosmic abundance based upon the analyses of 8 interior samples of 2 carbonaceous chondrites and 1 interior sample of each of 8 ordinary chondrites is a factor of 6.7 less than the previous low estimate. Our revised value, 3.0 B/1010H, is in excellent agreement with estimates based on observations of the solar photosphere. There is no longer a need to consider processes that enrich B in carbonaceous chondrites or deplete it in the sun. Relative meteoritic abundances of Li, Be and B are now in general agreement with models of nucleosynthesis of these light elements by galactic cosmic ray induced spallation. 相似文献
15.
《Applied Geochemistry》2006,21(4):643-655
The groundwater B concentration in the alluvial aquifer of the upper Cecina River basin in Tuscany, Italy, often exceeds the limit of 1 mg L−1 set by the European Union for drinking water. On the basis of hydrogeological and geochemical observations, the main source of the B contamination of groundwater has been attributed to past releases into streams of exhausted, B-rich geothermal waters and/or mud derived from boric acid manufacturing in Larderello. The releases were discontinued 25–30 years ago.This study confirms that the B dissolved in groundwater is anthropogenic. In fact, the δ11B values of groundwater B match the range −12.2‰ to −13.3‰ of the Turkish B mineral (colemanite) processed in boric acid manufacturing, in the course of which no significant isotopic effects have been observed. This isotopic tracing of the Cecina alluvial aquifer occurs just below the confluence of the Possera Creek, which carries the B releases from Larderello. Strontium isotope ratios support this conclusion.At about 18 km from the Possera Creek confluence, the groundwater δ11B drops to much more negative values (−22‰ to −27‰), which are believed to be produced by adsorption–desorption interactions between dissolved B and the aquifer matrix. The δ11B of B fixed in well bottom sediments shows a similar variation. At present, desorption is prevailing over adsorption because the releases of B-rich water have ceased. A theoretical model is suggested to explain the isotopic trends observed.Thus, B isotopes appear to be a powerful tool for identifying the origin of B contamination in natural waters, although isotopic effects associated with adsorption–desorption processes may complicate the picture, to some extent. 相似文献
16.
硼矿是重要的化工矿产资源,广泛应用于玻璃工业、陶瓷工业、洗涤剂和农用化肥。2014年至今,中国地质调查局组织编写的中国矿产地质志,全面总结了中国硼矿的资源特征和成矿规律。文章依托中国矿产地质志项目,总结了中国硼矿的成矿规律,圈定了硼矿找矿远景区,对未来硼矿的找矿工作有一定的参考价值。文章选取了具有代表性的矿床进行详细解剖工作,分别建立了现代盐湖型和沉积变质型典型硼矿床的预测模型。中国硼矿床的主要类型包括现代盐湖型、沉积变质型、地下卤水型、矽卡岩型和海相火山岩型。目前,中国共发现硼矿的矿产地216处,查明资源储量7575.69万t（B2O3）,分布在辽宁、西藏、青海、湖北等14个省（市、自治区）。在成矿时代上,中国硼矿主要形成于新生代、古元古代和中生代。在空间上,中国硼矿可划分为14个Ⅲ级成矿区带和11个矿集区。根据硼矿成矿预测成果,本文圈定了10个硼矿找矿远景区和8个优先勘查区,其中优先勘查区主要集中在青海油泉子（地下卤水型）,昆特依（现代盐湖型）,辽宁夹皮沟-红石砬子、吉林高台沟（沉积变质型）,西藏扎布耶茶卡、依布茶卡、麻米错、班戈错（现代盐湖型）等地区。 相似文献
17.
辽东—吉南地区下元古界硼矿床成因的商榷——兼论容矿大理岩及硼矿矿床的成因 总被引：1，自引：0，他引：1
辽东—吉南地区下元古界产有丰富的硼矿资源,半个多世纪以来几乎所有硼矿地质勘查报告及有关论文、专著等无不涉及矿床成因。关于硼矿床成因主要有沉积变质成矿、沉积变质再造成矿、超变质热液成矿等3种观点(称传统观点,下同),传统观点认为硼的成矿物质来源于下元古界地层,经混合岩化或超变质热液将地层中分散的硼活化、迁移至镁质大理岩富集成矿。在编纂《中国矿产地质志·硼矿卷》过程中,对辽吉硼矿进行了新一轮研究,认为传统观点硼矿床成因值得商榷,并提出碳酸岩岩浆期后含硼热液交代早期喷溢的碳酸岩成矿的论说。 相似文献
18.
J.D. Kleeman 《Geochimica et cosmochimica acta》1973,37(5):1321-1326
A replica of the surface texture of a rock section is produced on a Lexan plastic surface simultaneously with fission track formation by neutron irradiation. This effect, termed ‘Lexan plastic print’, is comprised of varying densities of tiny pits from (n, α) reactions with B and Li. Calculations have been made to estimate the abundances of Li and B which produced observed pit densities. 相似文献
19.
S. M. Aleksandrov 《Geochemistry International》2007,45(7):666-684
The succession of endogenic transformation of kotoite and accompanying minerals in marbles and calciphyres at hypabyssal magnesian-skarn deposits of boron is proved to be controlled by the anion composition of the hydrothermal solutions and the Mg mole fraction of the carbonate rocks. Early in the postmagmatic stage forming the B ore mineralization, the solutions contain Fe and F, as is reflected in the formation of kotoite and suanite in association with clinohumite, phlogopite, and Al-and Ti-bearing Mg-Fe borates, such as magnesiohulsite and magnesioludwigite. An increase in the F concentration of the hydrothermal solutions stimulates the formation of humites (from clinohumite to chondrodite and norbergite), which are replaced in the presence of kotoite by pertsevite (a hydroxofluorosilicateborate). In the calciphyres of Mount Brooks, Alaska, and at other deposits, the latter mineral is rock-forming in kotoite-clinohumite calciphyres, replaces this association, and is accompanied by fluoborite, nocerite, and fluorite. The further compositional transformations of the solutions with their enrichment in Cl result in the replacement of kotoite marbles and calciphyres and adjacent periclase marbles by sakhaite rocks with newly formed karlite. The neutralization of the hydrothermal solutions and their simultaneous cooling control the replacement of kotoite rocks by borcarite. The endogenic transformations of kotoite end with its szaibelyitization and/or brucitization and the simultaneous development of wightmanite in the marbles and the subsequent carbonatization of the borates. The research was carried out with the use of the author materials from boron deposits in Russia, Korea, Romania, England, France, and the United States. 相似文献
20.
Studies have been made of the boron content and distribution in recent Mytilus edulis shells by mapping the alpha particle distribution produced by the 10B (n,α)7Li reaction using cellulose nitrate track detectors. Boron is concentrated in the inorganic parts of the shell matrix and is enriched in aragonite relative to calcite by a factor of 1.5–2. The B contents in different parts of individual shells and in different specimens from a given locality are well defined, particularly for the aragonite layer. A correlation was found between the B in the aragonite layer and the salinity of the water in which the shells grew. The method shows promise as a means of using the boron content of fossil shells to determine paleosalinity. 相似文献