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1.
河南信阳高梁店乡铁铜矿矿区位于华北地台南缘陆壳增生带——东秦岭加里东构造岩浆带的东端,主体由二郎坪群火山、沉积、构造杂岩带构成.矿体主要呈透镜状产出于二郎坪群大栗树组第二岩性段斜长角闪(片)岩中,具有明显的层控特征,铁矿石中常见似层状黄铜矿,似层状矽卡岩化和硅化为近矿围岩的主要蚀变类型.根据矿床地质-地球化学特征,结合矿石的矿物共生组合、硫同位素组成及流体包裹体成分及特征,认为该矿床的形成与古生代二郎坪群的海相火山喷发沉积密切相关,早期的海底火山喷发形成了大量的玄武岩质熔岩(富含铁、铜),在火山喷发旋回的间歇期,形成了喷流沉积型的铁矿层和碳酸盐岩层;晚期受加里东末期-海西早期区域变质作用的影响,造成矿区基性火山岩变质形成层状矽卡岩,同时叠加了热液成因的浸染状、脉状铜铁矿化.故该矿床属于火山-沉积变质改造型含铜磁铁矿床. 相似文献
2.
闽中地区铅锌矿床辉石成分特征及其成因意义 总被引：6，自引：1，他引：6
文章在研究闽中地区铅锌矿床蚀变矿物组合的基础上,将辉石矿物的化学成分与典型矽卡岩Pb_Zn矿床的辉石成分进行了对比,认为该区铅锌矿床的辉石与典型矽卡岩中的辉石类似,为透辉石和钙铁辉石,富锰,具有远温端矽卡岩辉石的特征。因此推论本区铅锌矿床大部分类似于矽卡岩型Pb_Zn矿床,少数为受断裂控制的热液脉型矿床,是海底火山喷发沉积形成的初始矿源层经变质作用、燕山期构造_岩浆热液顺层交代、强烈叠加改造或活化并重新定位的矿床。 相似文献
3.
江西冷水坑矿田具有浅部斑岩型矿体与深部层状矿体的复杂组合。深部的层状矿体曾被长期认为是受构造破碎带控制的"层控叠改型矿体",与斑岩型矿体同期形成。本文从矿床的基本地质特征入手,论述和分析了层状银铅锌矿体所具有的火山碎屑建造及成矿特点,认为矿床具有三期成矿特点,层状矿体属火山机构控制的以火山集块-角砾岩层为赋矿岩石的火山喷发-沉积成岩矿体。提出了该矿床火山构造-岩浆喷发成矿系统的主要成矿要素和成矿模式,斑岩岩浆就位及其流体活动,在产生大规模斑岩型矿化的同时,对早期的火山沉积碳酸盐层进行叠加改造而形成了与斑岩具有成因联系的层控铅锌银矿床。 相似文献
4.
伊通县放牛沟地区早古生代岩浆演化特征及其与矿产关系 总被引：1，自引：0，他引：1
伊通县放牛沟早古生代岩浆活动较为强烈,其发展演化与放牛沟多金属硫化物矿床关系极为密切。岩浆活动特点是先喷发后侵入,先期形成钙碱系列的火山—沉积岩系,后期为Ⅰ型中酸性岩浆侵入。该矿床既有火山沉积特征,又有后期岩浆热动力改造特点,其形成受控于岛弧构造环境、火山活动形成的矿源层、后期热动力改造等因素。 相似文献
5.
阿舍勒块状铜-锌硫化物矿床产于中泥盆统阿舍勒组以英安质为主的钙碱性火山岩系中.矿化发生于中酸性火山喷发活动行将结束的阶段.矿床受岩性、火山穹丘和断裂控制.成矿物质主要来自火山岩浆热液、火山岩及海水.矿液主要由岩浆水和海水组成.矿床的形成经历了火山喷发沉积期、热液沉积充填期和矿床变质期.矿床是海底火山作用形成的热液沉积-交代充填成因的块状硫化物型矿床,可与黑矿型矿床对比. 相似文献
6.
青海省典型铁矿矿床特征及其成矿系列的浅析 总被引：1，自引：2，他引：1
青海省铁矿床（点）成因类型可划分为镁铁-超镁铁岩浆成矿系列的结晶分异型矿床；壳幔型中酸性岩浆成矿系列的热液型、矽卡岩型矿床；火山喷流-沉积成矿系列的层控型矿床；叠加改造成矿系列的层控改造型、改造热液型、沉积变质型矿床；沉积喷流成矿系列的层控型矿床；沉积成矿系列的陆、海相沉积型矿床．通过对这些成矿系列的典型铁矿矿床特征的研究，从其成矿构造地质环境分析，许多铁多金属矿床（点）均具有形成大型以上矿床的成矿地质条件，且多伴生铜、铅、锌、金银等多金属矿产。研究认为，在今后的找矿勘查过程中，应利用成矿系列的规律，并注重对共（伴）生组分的综合评价，这对扩大全省的找矿远景，提高资源综合利用水平，提高铁矿床技术经济价值具有重要的意义。 相似文献
7.
永平铜矿产于中石炭统地层中,是一大型的海底火山热液沉积经后期构造、岩浆改造的块状硫化物矿床。矿区产出“层状矽卡岩”,其规模远大于岩浆侵入体,与围岩整合产出。本文的研究表明:“层状矽卡岩”并非侵入体与碳酸岩发生接触交代作用的产物,而是沉积—火山沉积经后期改造形成的。“层状矽卡岩”与矿体在空间上共存,时间上经历了相同的发展阶段,“层状矽卡岩”对矿化起了进一步富集的作用。 相似文献
8.
阿尔泰可可塔勒铅锌矿床围岩蚀变及成因 总被引：2，自引：3，他引：2
可可塔勒铅锌矿床受火山喷发中心和沉积洼地控制，铅锌沉淀于海进阶段的局限还原卤水池中；矿下存在大型蚀变带，构成成矿流体对流循环过程中的水-岩作用带；后期造山挤压过程使地层和矿体倒转，矿床最终定位于麦兹倒转向斜之北东倒转翼的东南近转折部位。指出该矿床属海底火山喷流沉积改造型块状硫化物铅锌矿床。 相似文献
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10.
辽宁省铅锌矿床成矿作用研究 总被引：4，自引：1，他引：3
辽宁省铅锌矿床,根据其形成背景及物质来源可划分出岩浆热液型、矽卡岩型、陆相次火山热液型、变质海相火山热液型、变质同生沉积型、同生沉积－变质热液再造型、沉积－变质－岩浆热液叠加改造型、盆地热卤水型等８种类型。矿床特征显示出铅锌矿床的形成大多明显地受到了太古代绿岩带及早元古代以来碳酸盐岩地层的控制;在成因上多与优地槽环境下的海底火山活动、地壳深部的热环流作用及活化地台上的岩浆活动有关。铅锌矿床的成矿作 相似文献
11.
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
14.
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
15.
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
16.
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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18.
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
19.
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
20.
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