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庙背垅地区位于鹿井铀矿田中部,高昔铀矿床西南侧,铀矿化以碎裂蚀变岩亚型为主,赋矿围岩为印支期第二阶段中粗粒斑状黑云母(二长)花岗岩,含矿岩性有碱交代花岗(碎裂)岩、碱交代岩。近矿热液蚀变以钾长石化(碱交代)、赤铁矿化、水云母化、绿泥石化、碳酸盐化为主。岩石地球化学分析表明,赋矿围岩属S型花岗岩,可能是上地壳富铝的浅变质岩系在减压增温的条件下部分熔融的产物。含矿的碱交代花岗(碎裂)岩和碱交代岩SiO2含量依次降低,K2O与Fe2O3含量和Fe2O3/FeO值呈倍数增加,与其石英含量明显降低,碱交代、赤铁矿化发育相对应;高的U、Pb含量和更趋平坦的HREE配分曲线,表明碱交代作用不仅为成矿流体中铀元素的卸载沉淀创造了有利的物理化学环境,还可能活化了围岩中黑云母和副矿物里面的铀,同时铀的富集成矿可能与HREE的化学活动密切相关。这些特征是在鹿井矿田中部探寻碎裂蚀变岩亚型铀矿化的找矿标志。 相似文献
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河南安棚碱矿中自生沸石的产状及成因探讨 总被引:5,自引:0,他引:5
河南安棚碱矿为一蒸发成因的始新世重碳钠盐矿床。自生方沸石和钠沸石广泛发育在含碱段地层中,越靠近碱层沸石含量越高。两种沸石矿物分别以不同的产状分布于不同的岩石中。沸石与火山物质没有直接的联系。沸石的产状特征表明:化学沉积和胶体转变是方沸石最可能的成因,主要为准同生和成岩早期的产物。钠沸石主要为成岩阶段后期或成岩期后的产物。安棚磁矿的佛石矿物组合简单,产状复杂,反映了其独特的形成条件和环境。 相似文献
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碱交代作用的发育对于铀矿床的形成具有极为重要的意义,碱交代岩的特征与时代问题一直是铀地质工作者十分关注的关键问题。对诸广南部201矿床、361矿床、302矿床以及坪下水矿床的碱交代岩进行了室内外观测与鉴定并分别对采集的四个样品采用钾氩法直接测定碱交代岩的钾长石的年龄,测得其年龄分别为:201矿床(93.13±1.42)Ma,361矿床(75.46±1.47)Ma,302矿床(81.96±1.76)Ma,坪下水矿床(51.86±1.36)Ma。测年结果显示碱交代岩年龄比围岩年龄小得多,比矿床附近的中基性岩墙年龄也小,碱交代岩年龄与铀成矿年龄比较接近。 相似文献
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云南中部富碱斑岩区域成矿条件 总被引:6,自引:0,他引:6
云南省中部富碱斑岩形成于喜马拉雅山运动第一幕与第二幕之间的构造松驰阶段,由地壳深部的基性-超基性源岩经分离溶融而成,富碱斑岩成岩成矿作用受多级构造的控制;大地构造位置控制岩体呈带状分布;构造单元控制斑岩分区及特征;壳内大断裂及构造2交汇部位控制斑岩的产出;次级断裂控制斑岩的形态、产状和矿化定位。地质地球化学资料表明,成矿物质主要来源于岩浆,受岩浆的化学成分和成矿丰度的影响。不同岩区富碱斑岩特征和成 相似文献
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以安棚天然碱矿为例,通过分析泌阳凹陷天然碱矿的地质特征、底面构造特征、矿石特征,论述天然碱矿成矿地质条件、矿床成因,对天然碱矿进行了成矿预测。指出凹陷内安店次凹和程店次凹可能会有天然碱矿;南阳凹陷的汉冢、桐寨铺次级凹陷可能会存在碱矿,碱卤水层物质来源具有深源性;提出了钾、锂等矿床的勘查方向。 相似文献
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云南富碱斑岩是地洼阶段的产物,受大地构造位置和构造单元的控制。富碱斑岩形成于源岩的分离熔融过程,因此源岩的形成和演化又间接地控制斑岩的成岩成矿作用。构造历史-动力分析表明,源岩的形成是构造长期演化的结果。早在太古代初本区就形成雏壳,而后晚太古代原陆壳活动阶段起基性岩侵入的构成了富碱斑岩的岩的源岩,同时富集了部分成矿物质。地洼激烈期深部流体上侵引发源岩的重熔,使成矿物质进上步富集成为含矿岩浆。不同岩 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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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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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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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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