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通过对柳塘矿区铅锌多金属矿床的成矿地质条件、矿体地质特征、矿石质量、成矿因素进行分析,认为该矿床赋存于上古生界石炭系下统石磴子组碳酸盐岩与燕山期酸性侵入岩的接触带及附近,为地层、构造、岩浆岩、围岩蚀变联合控制。矿床类型、矿体分布、围岩蚀变种类均与岩体接触带、地质构造及控矿地层的分布密切相关,具有良好找矿前景。 相似文献
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莱芜市铁铜沟含金铜铁矿床产于中生代燕山期靳家桥角闪闪长玢岩与奥陶纪马家沟群五阳山段石灰岩的接触带,矿体形态严格受接触带控制。通过对矿区内地层、控矿构造、侵入岩、矿体特征和矿石质量的分析论述,认为该矿床为接触交代高温热液型含金铜磁铁矿矿床。 相似文献
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为了在黔西南泥堡金矿区获得找矿突破,进一步厘清矿床控矿因素,近年来,贵州省地质矿产勘查开发局一〇五地质大队根据其积累的黔西南地区金矿找矿经验建立了区域成矿模式,结合该区地表已知金矿体赋存特征,通过对以往大量地质资料再研究,并通过大量深部钻探工程验证,获得了一些新发现:二龙抢宝背斜是一次级褶皱,为隐伏的F1断层上盘的牵引褶皱;新发现了F1断层破碎蚀变带中的厚大金矿体,单矿体达大型矿床规模,从而使泥堡金矿达特大型矿床规模,并新发现了深部泥堡背斜核部的层控型矿体;在黔西南地区,首次在泥堡金矿区中二叠统茅口组中的断层破碎带内发现了金矿体。进一步研究得出泥堡金矿床的控矿因素是:①地层,泥堡金矿体主要产于中二叠统茅口组,上二叠统龙潭组一段、二段和三段;②构造,泥堡金矿体产于泥堡背斜南翼,主要受F1逆断层控制,其次受二龙抢宝背斜核部附近的构造蚀变体控制;③岩性,当岩石为角砾岩或砾屑砂岩、沉凝灰岩、不纯碳酸盐岩时有利于成矿,特别是岩层厚度较薄,成分复杂,孔隙多,其顶、底板为透水性差的黏土岩、粉砂质黏土岩时易富集形成金矿(化)体。 相似文献
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哈茨谱山北矿区位于青海省都兰县东部,其大地构造位置处于秦祁昆晚加里东造山系、东昆北造山带、祁漫塔格-都兰造山亚带的东段,区内构造活动和岩浆活动强烈。铜铅银金多金属矿矿床赋存于晚志留世英云闪长岩中,矿体产出严格受断裂构造控制,并受火山热液的叠加。矿体形态呈脉状、透镜状。通过对矿区内地层、控矿构造、侵入岩、矿体特征和矿石质量的分析论述,认为该矿床为中—低温火山期后热液型铜铅多金属矿床。 相似文献
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五莲县坤山透辉岩矿赋存于古元古代粉子山群张格庄组第三岩性段下部白云石大理岩层中,有水西何子和院上2个矿段,每个矿段由2个似层状矿体组成。矿体长154~264m,厚5.68~17.57m,矿体产状稳定。顶、底板围岩岩性均为白云石大理岩,2矿层间隔4~6m。透辉岩矿矿石特征与平度、莱西等地古元古代荆山群野头组赋存的透辉岩矿相似,矿石中化学成分变化稳定,Fe2O3含量普遍较低,矿石质量好,物化性能稳定,适于用做陶瓷原料。五莲县坤山透辉岩矿为严格受地层层位控制的变质沉积型矿床。 相似文献
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齐河-禹城地区位于山东省西北部,本文在系统分析区内铁矿成矿地质特征及成矿规律的基础上,与邯邢式、莱芜式铁矿进行了系统对比,提出了"禹城式"矽卡岩型铁矿矿床式,并初步构建了其成矿模式。区内发现李屯、郭店、大张3处富铁矿床,控矿岩体以闪长岩为主,围岩地层主要为石炭系—二叠系,少量奥陶系,矿体呈似层状,矿石以粒状结构、块状构造为主。区内"禹城式"铁矿以李屯矿床表现特征最为显著,矿体以接触带外部碎屑岩层间构造为主要赋存位置,主矿体赋存部位缺失灰岩及大理岩化带,以铁质巨量富集、伴生元素较少为显著矿质富集特征。早白垩纪,壳幔混合岩浆沿盆缘深大断裂上侵,混合岩浆上侵过程中富铁质岩浆热液出溶,受上覆碎屑岩地层屏蔽作用,岩浆热液与奥陶纪碳酸盐岩发生了充分的接触交代作用,并可能改造了沉积地层内"山西式"铁矿,促使磁铁矿经历多期叠加富集,在石炭系—二叠系内层间构造等部位富集形成富磁铁矿。 相似文献
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查干此老金矿位于内蒙古自治区乌拉特中旗境内,为岩浆热液型金矿床。该文系统阐述了查干此老金矿区地层、构造及岩浆岩特征,详细介绍了金矿床地质特征。通过对查干此老矿床的地质特征、控矿因素及矿床成因的系统研究,认为矿区的金矿化类型以含金石英脉型为主,兼有破碎蚀变岩型。金矿体赋存于二叠纪斜长花岗岩及志留纪蚀变闪长岩中的石英脉、碎裂岩带及糜棱岩带中,其产状、形态、规模严格受NE向断裂构造带控制,未受后期构造影响。该文对查干此老金矿床的构造背景、物质来源进行了研究,确定了该矿床的成矿模式,对该区的金矿成矿预测,深部及外围找矿工作具有一定的指导意义。 相似文献
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柴山水泥用灰岩矿矿床位于山东省曲阜市,矿床赋存于寒武纪九龙群张夏组地层中,区内断裂构造较发育,岩浆岩不发育。矿层分布于张夏组下灰岩段、薄层灰岩段和上灰岩段;矿石组分主要为方解石,矿石结构有鲕粒结构、生物碎屑结构、藻屑结构和内碎屑结构等;矿石构造主要有块状构造、云斑构造、叠层状构造等。矿石主要有用组分为CaO,Al_2O_3,Fe_2O_3,SiO_2;主要有害组分为MgO,K_2O,Na_2O,fSiO_2,SO_3,Cl~-;矿床平均化学组分CaO:52.02%,MgO:1.31%,矿石质量优良,Ⅰ级品矿石约占矿石总量的99.29%;矿层大部分裸露地表,底板为寒武纪长清群馒头组洪河段砂质灰岩、钙质砂岩等。矿床属海相化学沉积型矿床,矿层产状与地层产状一致,其产出部位明显受地层层位的控制。 相似文献
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王明远 《中国地理科学(英文版)》1993,3(4):376-380
We have made progress in medico-chemical geography as follows: the correlative law of organism with geochemical environment; the geochemico-ecological classification of chemical elements; the types of formative cause of biogeochemical provinces in China; the parabolic correlation between contents of iodine in drinking water and prevalence rate of endemic goiter; the discovery and proof of the low selenium zone in China; the successive discovery of endemic fluorosis of the types of pollution from burning coal, drinking high fluoride tea and high fluoride table salt from the year 1978; the study on chemical geography of schistosomiasis and the compilation of the Atlas of Endemic Diseases and Their Environments in the People's Republic of China. 相似文献
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随着信息社会的发展,新技术和新媒体的出现必然影响学校现代教育的发展。通过阐述发展学校电化教育的应注意的问题,探讨了解决问题的方法。 相似文献
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We used long term monitoring data to evaluate changes in abundance and species dominance of small-jellyfish (collected with zooplankton net whose bell diameter was less than 5 cm) between 1991 and 2009 in the Jiaozhou Bay, China. Zooplankton samples were vertically towed with conical plankton net from near-bottom to surface, identified microscopically, and mapped in time-space using Grapher 7.0 and Surfer 8.0. Results show that the abundance of small-jellyfish throughout the bay had been increasing during 2001-2009 on average of 15.2 ind./m 3 , almost 5 times higher than that between 1991 and 2000. The occurrence of peak abundance shifted from spring to summer after 2000, and two peaks appeared in spring and summer, respectively, after 2005. Both the abundance and the frequency of blooms of small-jellyfish increased after 2000 in the bay. In addition, the biodiversity of jellyfish has increased significantly in recent years with a change in dominant species. Several new dominant species appeared after 2000, including Rathkae octopunctata in winter, Phialidium hemisphaericum in spring, summer, and autumn, Phialucium carolinae in spring, and Pleurobrachia globosa in summer and autumn, while some previous dominant species throughout the 1990s (Eirene ceylonensis, Zanclea costata, Lovenella assimilis, and Muggiaea atlantica) were no longer dominant after 2000. The abundance of small-jellyfish was positively correlated with the density of dinoflagellates, and the abundance of zooplankton. We believe that the changes in smalljellyfish abundance and species composition were the result of eutrophication, aquaculture and coastal construction activities around the bay. Concurrently, seawater warming and salinity decrease in recent decades promoted the growth and reproduction of small-jellyfish in the bay. 相似文献
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Community participation in forest resource management in Nepal 总被引:2,自引:1,他引:1
KeshavL.Maharjan 《山地科学学报》2005,2(1):32-41
Livelihood of the people in Nepal hills depends much upon forest resources in addition to farming as forest plays a critical role in the well being of the farming households where access to alternative sources, such as energy for cooking, nutrition for animals, materials for fertilizer and constructing materials for shelter, are limited. Thus, the well being of the people in the hills is directly affected by the management of these forest resources. This issue was addressed in this paper by examining the forest resource management practices and its effect on well being of rural people in two different stages in a village lying in the steep hill of Mahabharat Range in the southern hills of Kathmandu valley, Lalitpur District. The main ethnic/caste groups in the villageare Brahmin/Chhetri (high Hindu caste),Magar/Tamang (Tibeto Burmans) and Kami (occupational caste: cobbler). Currently there are four community forest users groups, with mixed ethnic membership, organized to manage the forest resources. The endowments, weak institutional settings, before 1990 helped the Bhramins, Magars and Tamangs to get access into the private forest endowment, which made them easy to get access to the forest resources, mainly fuel wood, fodder and timber in 1990 and enhanced their well beings. But the socially backward Kami could not get benefit from the institutions that existed during that time and had less chance to enhance their well beings. After the set up of different endowments during late 199os, i.e.,hand over of forest management to users groups in line with the concept of community forest,environment to use the forest resources became better for all the groups, along with the management of the forest. This enhanced the well beings of all the groups in the study village. However, the ability of Kami to use the forest resources to enhance their well beings was still lacking behind. The reason was partially due to the difference in endowments carried over from the endowments before 199o, and partly due to their occupational work and location of their settlements. 相似文献
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刘希林 《中国地理科学(英文版)》1995,5(3):275-287
RECENTDEVELOPMENTSINDEBRISFLOWRESEARCHINITALYMarchiLorenzo;TeccaPiaR.(InstituteforPreventionofHydrologicalandGeologicalHazard... 相似文献