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利用黄铁矿进行找金是一种新的地球化学找矿方法。其特点是黄铁矿在矿化作用的早期对金及其伞生元素的富集，使金矿外围散染状黄铁矿中出现的金的异常；在金的成矿时期，由于自然金的形成，黄铁矿中金的含量下降。 相似文献
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在不同建造金矿床中,石英、黄铁矿、方铅矿中的金含量变化具有相同的趋势:在成矿前早期的石英和黄铁矿中金含量不高,在早成矿期组合中石英的金含量提高1—2个数量级,紧接着在主成矿期组合中石英,黄铁矿、方铅矿含金最高,在与金矿有成因联系的围岩中,其石英有较高的金含量,则反映这种联系。这对于划分含矿和不含矿的火山机构具有重要意义。 相似文献
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热液金矿成矿作用地球化学研究综述 总被引：4，自引：2，他引：2
文章总结了热液金矿成矿地球化学研究进展,其中包括含金热液来源、控制岩浆热液中金浓度的因素、金在热液中的富集和沉淀机制以及热液金矿成矿地球化学环境.含金岩浆演化早期,磁铁矿、磁黄铁矿和钛铁尖晶石结晶分异会影响岩浆演化形成热液型金矿的能力.与金成矿有关的地热流体中w(Au)为1×10-9～80×10-6,岩浆热液中w(Au... 相似文献
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丘岭金矿床是西秦岭地区重要的卡林型金矿之一, 金矿化赋存于上泥盆统南阳山组和下石炭统袁家沟组地层中, 容矿岩石的岩性为钙质粉砂岩、粉砂质页岩和泥质灰岩.金矿石中主要金属矿物为黄铁矿和毒砂, 非金属矿物则以石英、方解石和绢云母为主.通过对矿石矿物黄铁矿和毒砂的扫描电镜-能谱分析、电子探针分析和激光剥蚀电感耦合等离子体质谱分析, 对丘岭金矿床金的赋存形式和富集机理进行了较为详细的研究.结果表明, 丘岭金矿床中金主要以次显微不可见金的形式存在, 其次为显微可见金.次显微金包括: (1)固溶体金(Au+), 主要存在于环带状细粒黄铁矿的含砷增生边区域和毒砂中, 少量存在于环带状黄铁矿的核部不含砷区域; (2)纳米级自然金颗粒(Au0), 存在于粗晶黄铁矿中.环带状细粒黄铁矿核部的次显微金可能主要以胶体吸附的形式存在, 暗示容矿岩石在沉积成岩过程中有金的初步富集, 而环带状黄铁矿幔部和毒砂中的Au则主要来源于成矿流体, 以S和As的络合物形式搬运.显微可见金主要分布在细粒黄铁矿的晶体边缘和热液蚀变绢云母、石英及方解石中, 粒径通常小于3~5 μm, 其形成可能与成矿流体中金的局部过饱和及成矿流体对细粒黄铁矿和毒砂中次显微金的活化和再次富集有关. 相似文献
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坑头金矿位于贵州黔东南金矿带,前人对该金矿带石英脉型金矿进行了广泛研究,认为深部可能有蚀变岩型金矿存在,但都未证实。近期经综合研究,在坑头金矿施工钻孔发现坑头金矿的深部存在蚀变岩型矿体,含金量最高达6. 65 g/t。蚀变岩型金矿矿石中金的赋存状态以裂隙金为主,主要载金矿物为毒砂。硅化蚀变及断层与金矿化关系密切,金矿体位于硅化蚀变发育的构造破碎带中。目前,黔东南金矿的开采目标多为300 m以浅的石英脉型金矿体,因此该发现对黔东南地区金矿深部勘查工作具有重要意义。 相似文献
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造山型金矿中金的来源是目前广泛争论的问题,尽管变质成因模式受到了较多的关注,但研究实例还不多。加里东期是华南地区重要的金矿成矿期,浙江诸暨陈蔡杂岩发育了从绿片岩相到角闪岩相的岩石组合,变质时代为加里东期,同时,其变质温度和压力等都已经得到精确厘定,为研究华南加里东期金矿形成与变质作用的关系提供理想的研究剖面对象。通过系统采集陈蔡杂岩岩石样品,在详细的岩相学研究的基础上对其中的黄铁矿中的金及亲硫元素进行了激光剥蚀-电感耦合-等离子体质谱（LA-ICP-MS）原位微区微量元素分析。研究结果表明：陈蔡杂岩角闪岩相岩石岩相学特征中有绿泥石,角闪石退变质为黑云母,反映退变质作用中有变质流体的回流。华南加里东期变质过程中,从绿片岩相到角闪岩相的相变过程中金及其他亲硫元素从主要赋存矿物黄铁矿中释放出来,进入变质流体,为江南造山带造山型金矿提供了金属来源。利用硫化物单矿物进行金的含量原位分析是解决变质过程中金活化迁移的重要手段。并提出华南加里东期变质过程中金的来源模式图。 相似文献
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《现代地质》2016,(2)
江苏仑山金矿床为新发现的小型金矿床,金矿体赋存于白垩系杨冲组地层中,容矿岩石为碳质泥岩和泥质粉砂岩。金矿石中金属矿物以黄铁矿为主,少量黄铜矿、方铅矿和闪锌矿,非金属矿物为石英、方解石、萤石和绢云母等。成矿阶段分为沉积成岩阶段和热液阶段,后者又细分为Ⅰ和Ⅱ两个亚阶段,沉积成岩阶段和热液Ⅰ亚阶段为主要的成矿阶段。通过典型矿石的扫描电镜-能谱分析以及矿石矿物黄铁矿的电子探针分析,对仑山金矿床金的赋存形式和富集机理进行了初步探讨。结果表明,仑山金矿床中金以显微不可见金和显微自然金二种形式存在,显微不可见金以纳米级自然金(Au0)和固溶体金(Au+)的形式赋存于黄铁矿中,自然金以粒间金和裂隙金的形式赋存于碎屑石英颗粒之间和碎屑石英裂隙中。沉积成岩阶段草莓状黄铁矿、细粒黄铁矿和针状黄铁矿的Co/Ni比值均大于1,暗示其可能受到后期热液作用影响。沉积成岩阶段容矿地层发生了金的预富集,后期热液成矿阶段流体叠加作用最终导致了仑山金矿床的形成。 相似文献
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黄铁矿中不同赋存状态金的测试及意义
—以胶莱盆地金矿中黄铁矿为例 总被引：1，自引：0，他引：1
本文论述了黄铁矿中晶格金、自然金、石英包体金的分离技术及测试方法,它可用于研究金矿载金矿物黄铁矿中不同赋存状态金与成矿的关系。运用本方法对胶莱盆地典型金矿中主成矿阶段黄铁矿三种赋存状态的金进行了测试,发现以自然金为主,且自然金含量比例差别不大,说明盆地中的金矿可能具有相同成矿流体和环境。通过对含矿与不含矿黄铁矿中离子晶格金含量研究,进行了靶区预测验证。研究发现黄铁矿中存在石英包体金,且部分金矿中石英包体金含量较高,普通测试方法可能丢失该类金,造成样品分析结果偏低,进而出现丢矿或资源量估算不准确的现象。 相似文献
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CSAMT 法在辽西康杖子区深部探矿中的应用 总被引：5，自引：0，他引：5
可控源音频大地电磁法(CSAMT)具有探测深度大、横向分辨率高、抗干扰能力强的特点,在深部找矿勘探中有着重要的指导意义。肖家营子铜钼矿床是辽西地区一个大型矽卡岩型金属矿床,大部分矿体是隐伏矿体,矿区外围的康杖子区与本区有相似的成矿地质环境,成矿地质条件优越.矿体与围岩电性差异明显,通过应用CSAMT,矿体具有低电阻特点,根据成果推断解释,对深部有利成矿部位进行了钻探验证,取得了理想的探矿效果,在矿区外围取得第二深度空间找矿重大突破。 相似文献
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Trends in landslide occurrence in Nepal 总被引：2，自引：0，他引：2
David N. Petley Gareth J. Hearn Andrew Hart Nicholas J. Rosser Stuart A. Dunning Katie Oven Wishart A. Mitchell 《Natural Hazards》2007,43(1):23-44
Nepal is a mountainous, less developed kingdom that straddles the boundary between the Indian and Himalayan tectonic plates.
In Nepal, landslides represent a major constraint on development, causing high levels of economic loss and substantial numbers
of fatalities each year. There is a general consensus that the impacts of landslides in countries such as Nepal are increasing
with time, but until now there has been little or no quantitative data to support this view, or to explain the causes of the
increases. In this paper, a database of landslide fatalities in Nepal has been compiled and analysed for the period 1978–2005.
The database suggests that there is a high level of variability in the occurrence of landslides from year to year, but that
the overall trend is upward. Analyses of the trends in the data suggest that there is a cyclicity in the occurrence of landslide
fatalities that strongly mirrors the cyclicity observed in the SW (summer) monsoon in South Asia. Perhaps surprisingly the
relationship is inverse, but this is explained through an inverse relationship between monsoon strength and the amount of
precipitation in the Hill District areas of Nepal. It is also clear that in recent years the number of fatalities has increased
dramatically over and above the effects of the monsoon cycle. Three explanations are explored for this: land-use change, the
effects of the ongoing civil war in Nepal, and road building. It is concluded that a major component of the generally upward
trend in landslide impact probably results from the rural road-building programme, and its attendant changes to physical and
natural systems. 相似文献
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Julie Okpala 《GeoJournal》1990,20(1):37-43
This paper traces the development of geographic education in Nigeria and examines the views of geographers, other academics,
students and the public at large about the importance of geography. Geography's value is immense despite the non-professional
nature of the discipline. Nevertheless, there is a need to define geography's status and ensure career prospects for students.
The Nigerian Geographical Association (from classroom teaachers to top geographers) must promote geography, improve its status
in schools and universities, and continuously restructure its content and methods to address pertinent social needs. 相似文献
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Takeshi Nose Dr. 《GeoJournal》1985,10(3):261-276
Conclusions During the last ten years, aquaculture, especially mariculture has undergone remarkable expansion to counter-balance the gap between the supply and demand of fishery products in Japan. Its expansion has also been supported by the traditional preference of the Japanese people for seafood. Mariculture is now being forced to change its structure due to adverse economic circumstances such as the rise in the cost of energy, feeds and other materials for culture, low market prices, deterioration of environmental conditions, and many other factors. Before these constraints can be resolved, advanced scientific knowledge and technologies must be integrated to develop new types of aquaculture. Expansion of maricultural activities to more open-sea and off shore areas would be one route to follow. Technologies for the development of formulated diets not only for young but also for adults and larvae, establishment of feeding standards, prevention of epizootic diseases must support the establishment of modern aquaculture.The culture-based fisheries, or marine ranching, is becoming a subject for further development in Japan. Much research work has been conducted with a great degree of governmental support. Establishment of a net work of seedstock production farms has made it possible to carry out releasing experiments on a large scale. A newly integrated restoration system could be developed on the basis of these experiments, even though the profits resulting from the artificial restoration of stocks is not thouroughly verified at present. The commencement of a national scheme for culture-based fisheries would be a manifestation of the enthusiasm of the Japanese fish industry. 相似文献
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2010年,美国铀矿总共施工7 209个钻孔,总进尺1 493 520 m;生产铀1 628.55 t;铀矿业总支出费用为2.773亿美元,其中铀矿地勘费支出为3 450万美元,占铀矿业总费用的12.44%。铀矿地勘钻探费用为4 460万美元,占铀矿业总费用的16.08%。 相似文献
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硫代砷是富硫化物地下水中砷的重要形态,对环境和人类健康有潜在威胁。目前硫代砷研究程度尚低,本次主要针对国内外地下水（地热水）中硫代砷的存在形态,水文—生物—环境地球化学过程,样品保存,定量检测方法等方面进行研究。结论如下:pH, 氧化还原电位,硫化物含量和微生物作用等是影响地下水中硫代砷稳定存在和形态分布的重要因素。含铁矿物能与水中的硫代砷形成配位键对其进行吸附,吸附性普遍弱于（亚）砷酸盐,因此,地下水中硫代砷可能表现出更强的迁移性。用于硫代砷检测的自然水样在采集中可采取过滤,速冻,厌氧和低温短期保存的操作流程,以减缓该形态的转化甚至消失。色谱联用ICP-MS系统可用于自然水样中硫代砷的分离定量检测,紫外—可见分光光度法和X射线吸收光谱法在不同场景下也可对硫代砷进行定量和表征分析。地热水和浅层地下水中均可能存在硫代砷,由于水样中硫代砷的不稳定性,室内检测和分析难以准确反映现场过程,因此,野外样品保存技术和现场检测方法的更新可能在未来有更大研究空间,值得进一步探索。 相似文献
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内蒙古苏尼特地下水氟污染形成机理研究 总被引：4，自引：1，他引：3
为了研究内蒙古苏尼特地区地下水氟污染机理,本文运用水文地球化学分类方法,从水文地质、水化学特征两方面研究其地下水的水质特征、氟的起源、分布规律及污染形成机理。研究结果发现:高氟地下水的主要水质类型为HCO3—Na型,pH值在7.08～9.38之间,氟浓度与井深有关,即井越浅,氟浓度越高;地下水中氟浓度最高达14.78mg/L,5～9月地下水氟浓度相对增长率在7.8～23.1之间;F-浓度与Li+、Br-相关系数达0.89和0.82,受断层影响的深层地下水中F-浓度几乎与Li+、Br-没有相关关系,这暗示着氟来源于浅部,并受到强烈的蒸发作用影响而使水中的氟浓缩;地质调查发现该地区还有数个萤石矿存在,显微镜分析结果证实表层土壤中普遍存在CaF2,地下水中的氟来自CaF2。高氟地下水存在于潜水层,深部含水层的地下水可供开采。从断层带涌出的水对潜水层有稀释作用。 相似文献
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Radon is a radioactive gas emanating naturally from uranium rich granites and shales. It may be emitted from the ground surface into the atmosphere as a gas, or it may be dissolved into stream water and transported over distance. The levels of radon gas in soils at ground surface depend on a number of factors relating to the source of the gas and to its transmission. Igneous rocks contain the highest mean concentrations of radium and uranium. The depth of cover is relevant also. Surveys over the years by the National Radiological Protection Board (NRPB) and others have indicated that the highest concentrations in the United Kingdom occur in Cornwall, Devon and northeast Scotland. However, recent reports have indicated that high concentrations of the gas may be detected in small pockets in counties outside of those considered at high risk. This survey relates to a series of measurements taken in and around Darlington, County Durham. The results showed the presence of small areas with strong concentrations of radon in soil gas, but only minor levels of dissolved gas in stream waters. 相似文献