辽宁东五家子金矿矿脉含矿性评价标志研究   总被引：2，自引：1，他引：1       下载免费PDF全文

朴寿成  师磊  杨明亮  王宝岩 《地质找矿论丛》2008,23(3):204-208

辽宁东五家子金矿的矿脉由蚀变岩和石英脉透镜体构成,可采矿体均为硫化物石英脉型.工业矿脉中,石英为烟灰色,发育他形、半自形的细粒黄铁矿等硫化物,有较大规模的矿体.矿化脉中,石英为乳白色,发育粗粒、自形的浅色黄铁矿,无可采矿体.在工业矿脉、次要矿脉、矿化脉的蚀变岩和石英脉样品中,Au,Hg与其他元素的相关性有明显区别.用石英脉样品的As-Ni-Ba图解和蚀变岩样品的Au-Ag-Ba图解预测,矿区外围的西沟1号脉和西沟3号脉属于工业矿脉.  相似文献   

北京市土壤Hg污染的区域生态地球化学评价   总被引：8，自引：1，他引：7  

成杭新  庄广民  赵传冬  杨柯  聂海峰  刘飞  黄宏库  范辉  阮启和  冯辉 《地学前缘》2008,15(5):126

城市土壤Hg异常/污染是中国普遍存在的重大生态环境问题。文章对北京市近1000km2范围内的地表土壤、壤中气、大气干湿沉降、大气颗粒物、大气中的Hg含量水平和空间分布模式进行了系统研究,查明北京地表土壤Hg平均含量为0.41mg/kg,大气干湿沉降物中的Hg平均含量为0.194mg/kg,壤中气Hg的平均含量为559.65ng/m3,大气颗粒物PM10和PM2.5中的Hg含量分别为0.59和0.67ng/m3,大气中的Hg平均含量为3.13ng/m3。北京市自2000年起实现了由燃煤转变为燃气的减排措施,导致干湿沉降物中的Hg沉降通量显著减少,2006年大气干湿沉降物中Hg的沉降通量1.837mg·m-2·a-1,北京市城区(近1000km2)Hg全年沉降为1837kg,空气中总Hg浓度由1998年的8.3~24.7ng/m3下降到2006年的3.13ng/m3,大气颗粒物中Hg含量由2003年的1.18ng/m3下降到2006年的0.59ng/m3(PM10)和0.67ng/m3(PM2.5),表明北京市煤改气减排措施的实施显著改善了大气环境质量。通过对土壤中Hg的存在形式研究,发现土壤中有硫化物(辰砂)及各种Hg盐(HgCl2)的含Hg矿物,Hg也可以各种吸附方式或壤中气方式存在。研究证实北京壤中气Hg与大气Hg存在显著的相关性(n=131,R=0.267,p<0.01),表明壤中气Hg是大气Hg的重要来源之一。利用2005年地表土壤总Hg与Hg释放速率的线性方程估算,土壤Hg平均释放速率为102.42ng·m-2·h-1,2005年土壤释放进大气的Hg通量为936.70kg。在查明土壤中存在大量辰砂矿物的同时,还分布有大量具有高温熔融特征的金属微球粒和玻璃质微球粒,证明燃煤和冶金烟尘是地表土壤Hg的主要来源。土壤中Hg、S、pH和辰砂颗粒浓度在空间上的高度耦合性表明,碱性条件下,土壤中高含量的S和Hg是辰砂形成的重要原因。按国家土壤环境质量标准,北京市I级土壤Hg环境质量的面积为176km2,Ⅱ级为808km2,Ⅲ级为24km2,超Ⅲ为36km2。Ⅲ级、超Ⅲ级主要分布在二环路以内的中心城区。城南(长安街为界)大气Hg环境质量明显优于城北,在北四、北五环之间的部分地区,大气颗粒Hg的环境质量为Ⅲ级或超Ⅲ级。在地表土壤Hg含量较高的中心城区,居民每天因呼吸摄入的Hg高达364ng,对人体健康构成潜在风险。根据我国"十一五"规划中每年实现10%节能减排的目标,对北京市未来50年土壤Hg含量的时空演变趋势预测,预测2050年北京因干湿沉降带来的Hg输入量为16.03kg,地表土壤释放Hg的输出量为37.36kg,明显大于Hg的输入通量,土壤Hg的环境质量将得到根本改善。预测到2040年Ⅲ级土壤Hg环境质量的区域将完全消失,到2060年以Ⅰ级土壤为主。  相似文献   

河北省白洋淀洼地环境地球化学物源判断   总被引：7，自引：1，他引：6  

张秀芝  郭海全  李宏亮  李建华 《地学前缘》2008,15(5)

河北省白洋淀洼地是一个大型天然平原洼地,在洼地的深、浅层土壤中均发现了以Cu、Pb、Zn、Cd为主的多变量地球化学异常。运用地球化学特征法、参考元素法及多元统计法,对深、浅层土壤Cu、Pb、Zn、Cd异常的性质和成因进行了判别。结果表明,深层土壤异常与特定的地球化学沉积环境有关,以自然地质作用成因为主,而浅层土壤异常具有典型的二元叠加特征,以人为源的输入为主。  相似文献   

Mesozoic-Cenozoic tectonics and geodynamics of Altai, Tien Shan, and Northern Kazakhstan, from apatite fission-track data     

M.M. Buslov  D.A. Kokh  J. De Grave 《Russian Geology and Geophysics》2008,49(9):648-654

Apatite fission-track (AFT) thermochronological modeling as a diagnostic tool for periods of stability (peneplanation) and tectonic activity (orogeny) has been broadly used in tectonic studies of Central Asia in recent years. We discuss more than 100 AFT ages of samples from the Kyrgyz Tien Shan and Altai and compare them with AFT data from northern Kazakhstan. Geological, geomorphological, and AFT data indicate intense activity in the Late Cenozoic Eurasian continental interior. The impact from the India-Eurasia collision on the northern Tien Shan, Altai, and northern Kazakhstan regions showed up at 11, 5, and 3 Ma, respectively, as a result of stress propagation into the continent, with the ensuing reactivation and mountain growth. We hypothesize that a distant effect of the Late Cenozoic India-Eurasia collision was to rejuvenate Paleozoic fault zones and to deform the Mesozoic sedimentary cover north of the collision front as far as the West Siberian Plate. The reactivation facilitated formation of tectonic oil and gas traps. The activity in northern Central Asia under the effect of the Indian indentation into Eurasia appears to continue and may evolve to include uplift of southern West Siberian plate with uplift.  相似文献   

Recommended Values of ²³⁹Pu, ²⁴⁰Pu and ^239+240Pu Concentrations in Reference Material IAEA-315 (Marine Sediment) Estimated by Thermal Ionisation Mass Spectrometry, Inductively Coupled Plasma-Mass Spectrometry and Alpha Spectrometry     

Taeko Shinonaga  Helmuth Aigner  Dilani Klose  Peter Spinder  Heinz Fröschl  David Donohue 《Geostandards and Geoanalytical Research》2008,32(1):93-101

The recommended concentrations of ²³⁹Pu, ²⁴⁰Pu and ^239+240Pu in reference material IAEA‐315 (marine sediment) were estimated by three analytical methods: isotope dilution thermal ionisation mass spectrometry (TIMS), isotope dilution inductively coupled plasma‐mass spectrometry (ICP‐MS) and alpha spectrometry. The determination of ²³⁹Pu and ²⁴⁰Pu (^239+240Pu by alpha spectrometry) was carried out with samples from randomly selected bottles using each method. Plutonium‐238 was also measured by alpha spectrometry. A plutonium‐242 reference material was used as a spike for the quantitative analysis. The influence of ²⁴²Pu in the samples was therefore calculated; however, this contribution was less than the range of uncertainty and did not influence the final results. The obtained data were statistically analysed using variance component analysis and paired comparison. The combined standard uncertainties from “method/measurement”, “bottle” and “sub‐sample” were in the order of 3 to 6%. The main contributions to the uncertainty were from the material heterogeneity and from systematic differences between methods. Based on this study with twenty‐seven analyses using 10–14 g sample mass, concentrations of (38 ± 3) Bq kg^?1, (28 ± 3) Bq kg^?1 and (66 ± 4) Bq kg^?1 are proposed as recommended values for ²³⁹Pu, ²⁴⁰Pu and ^239+240Pu, respectively, and (9.5 ± 0.4) Bq kg^?1 for ²³⁸Pu as an information value in reference material IAEA‐315. In mass concentration units, these amount to (16.4 ± 1.2) ng kg^?1, (3.3 ± 0.4) ng kg^?1 and (0.015 ± 0.003) ng kg^?1 for ²³⁹Pu, ²⁴⁰Pu and ²³⁸Pu, respectively. The certified reference materials NIST 4350B and NIST 4354 were also analysed by TIMS for quality assurance of the method used in this study.  相似文献   

Springs of Great Britain     

J. B. W. Day 《Environmental Geology》1996,27(2):77-78

Predictably, in a country such as Britain, with its preponderance of consolidated, sedimentary, mainly fissure-flow aquifers, there is a very large number of springs, many of which are, or have been, used for public supply. Migratory springs are a feature of the British (Ur. Cretaceous) Chalk, the most important British aquifer. The Chalk's low specific yield and high capillary moisture retention together give rise to very considerable fluctuations (more than 33 m in some areas) of the unconfined water table. Along the gentle dip slopes of the Chalk (North and South Downs of southern and southeastern England) springs may migrate laterally for several miles, giving rise to seasonal streams locally known as bournes or lavants. However, springs such as at Duncton, West Sussex, at the base of the much steeper scarp slopes of the Chalk, form point sources, the flows from which tend to be relatively steady; such springs commonly supply and are the original reason for the existence of many of the small towns and villages which nestle along the bases of the chalk scarps of Sussex and Kent.Where the Chalk forms coastal cliffs, a number of springs break out at the base of the cliff between high and low tide levels; there are major chalk coastal springs, for instance, at St. Margaret's Bay (Kent) and at Arish Mells, east of Lulworth Cove, Dorset. Such springs are not used for direct supply (their salinity is usually too high) but are indicators of the presence of local reserves of groundwater for possible future development.  相似文献   

On the spatial characteristic of the short term and imminent anomalies of underground water behaviors before strong earthquake     

杜学彬  刘耀炜  倪明康 《地震学报(英文版)》1997,10(4):523-533

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Increasing of efficiency of desulphurisation processes of coals during thermal destruction     

Turchanina Oksana Satin Vladimir Derevyanko Aleksey 《中国地球化学学报》2006,25(B08):51-52

As is well known, a high content of sulphur in coals is an effect of the post-depositional history of coal seams and one of the most important criteria of its use as a fuel. Sulphur in coals can cause a serious environmental and technological problem during their utilization. This problem is very actual for the Donetsk Basin because 734 mined seams out of the total of 1009 （73%） are comprised of coals with sulphur content -2%. The chemical pre-treatment as a first stage in their processing is widely used in order to effectively obtain the thermal destruction products of coals （such as semi-coke, coke, adsorbents, etc.） and to simultaneously utilize coal wastes. Development in pre-treatment methods for high-sulphur, low-rank coals is especially desirable for reducing the sulphur contents of the solid products. The aim of the present work is to investigate the influence of coal pre-treatment on the yield and composition of thermal destruction products, and the sulphur distribution among different components of the coals of different genetic types by reductivity （low-reduced LRC and reduced RC coals）. The thermal behavior of the coals was studied by means of the Fisher method （heated to 520℃, at a rate of 7℃/min）. The composition of the semi-coking gas was investigated by means of a VTI gas analyzer. The coal samples were chemically treated directly before thermal destruction by the introduction of 1-% solutions of radical polymerization initiator AAD （acrylic acid dinitrile C8H12N4） and products of coal-tar distillation （absorber oil）. Coal pre-treatment increases the semi-coke yield and its coking ability, and changes the liquid/gaseous product ratio.  相似文献   

Controls on low-pressure anatexis   总被引：2，自引：0，他引：2  

C. C. GERBI  S. E. JOHNSON  P. O. KOONS 《Journal of Metamorphic Geology》2006,24(2):107-118

Low-pressure anatexis, whereby rocks melt in place after passing through the andalusite stability field, develops under more restricted conditions than does low-pressure metamorphism. Our thermal modelling and review of published work indicate that the following mechanisms, operating alone, may induce anatexis in typical pelitic rocks without inducing wholesale melting in the lower crust: (i) magmatic advection by pervasive flow; (ii) crustal-scale detachment faulting; and (iii) the presence of a high heat-producing layer. Of these, only magmatic advection by pervasive flow and crustal-scale detachment faulting have been shown quantitatively to provide sufficient heat to cause widespread melting. Combinations of the above mechanisms with pluton-scale magmatic advection, shear heating, removal of the lithospheric mantle, or with each other provide additional means of developing suitable high temperatures at shallow crustal levels to generate low-pressure anatexis.  相似文献   

The relationship between depth, age and gravity in the oceans   总被引：2，自引：0，他引：2  

A. G. Crosby  D. McKenzie  J. G. Sclater 《Geophysical Journal International》2006,166(2):553-573

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