Geochronology and Geochemistry of Metallogenetic Porphyry Bodies from the Nongping Au-Cu Deposit in the Eastern Yanbian Area,NE China: Implications for Metallogenic Environment     

REN Yunsheng  JU Nan  ZHAO Hualei  WANG Hui  HOU Kejun  LIU Shen 《《地质学报》英文版》2012,86(3):619-629

The metallogenetic porphyry bodies in the Nongping Au-Cu deposit, in the eastern Yanbian area, mainly include porphyritic granodiorite and biotite granodiorite porphyry. They are featured with high silicon and enrichment in sodium, and classified into sodic rocks of low-K tholeiitic basalt series. Except slightly low Sr content, the rock basically has the geochemical characteristics of the adakite: relatively high A12O3 content, relatively low MgO content, depletion in Y and Yb; relative enrichment in large ion lithophile elements (LILEs) and light rare-earth elements (LREEs), relatively low content of high field strength elements (HFSEs); positive Eu anomaly or weak negative Eu anomaly. In situ zircon dating technology LA-MC-ICP-MS was used to conduct single-grain zircon dating of biotite granodiorite porphyry, and the results show that the age of metallogenetic porphyry body is 100.04±0.88 Ma, indicating that the porphyry bodies were emplaced in the late Cretaceous period. According to the regional tectonic setting and the comparison with the same kind of deposits, we think that the metallogenetic porphyry bodies in the Nongping Au-Cu deposit have a close genetic connection with the subduction of the Pacific plate in the late Yanshanian period. The adakitic magma generated from partial melting of the subducting plate has high formation temperature, high oxygen fugacity, and volatile constituents’ enrichment, so it is helpful for enrichment of metallogenetic elements and plays an important role in the formation of porphyry Au-Cu deposits in this region.  相似文献   

关于抗滑桩与岩土体相互作用研究的机理探讨     

龚国华  覃京音  黄非 《矿产与地质》2012,26(3):260-264

在滑坡工程的治理设计中,最基本的问题之一是发生变形的边坡或滑坡岩土体与支挡结构的相互作用问题.文章主要研究抗滑桩与岩土体之间相互作用问题,就滑坡推力传递机理进行了分析,并对滑坡推力和土体抗力分布图式和分布函数进行了探讨.建议在滑坡治理工程中对抗滑桩进行优化设计,将使工程治理更为经济合理.  相似文献   

环境因子对浙江沿岸春季日本鲐(Scomber japonicus)幼鱼生长、分布的影响     

朱文斌  崔国辰  胡翠林  朱海晨  王雅丽  蒋日进  张亚洲  冯春雷 《海洋与湖沼》2021,52(6):1448-1455

浙江沿岸海域是日本鲐（Scomber japonicus）的重要产卵场。当前针对日本鲐幼鱼生长发育的研究较少,而环境因子会对其生长、分布造成较大影响。根据2019年5月的科学观察员取样数据和环境数据,对其群体组成进行研究,运用Pearson相关性分析、广义加性模型（GAM）探究其分布及个体大小的影响因子,利用克里金插值法定量分析溶解氧对日本鲐幼鱼分布影响。结果表明：海水表层盐度（Sea Surface Salinity,SSS）是影响日本鲐幼鱼分布的主要环境因子,幼鱼集中分布于27.5-27.8盐度海域;浙江沿岸南部海域日本鲐幼鱼叉长、体重均值分别为37.6 mm、0.659 g,中部海域叉长、体重均值分别为64.2 mm、3.305 g,南部、中部海域间鲐幼鱼大小存在显著性差异（P<0.05）;日本鲐幼鱼个体大小主要受溶解氧和纬度影响,个体大小与溶解氧呈多波峰的非线性关系,随纬度增加呈先减小再增大趋势。研究表明：溶解氧是影响浙江沿岸日本鲐幼鱼生长、分布的关键环境因子;结合幼鱼分布特征及个体大小差异,推测浙江沿岸海域日本鲐幼鱼来自不同产卵批次。  相似文献   

论岷山地区冰缘岩溶     

周绪纶 《四川地质学报》2013,(4):479-487

岷山地区冰缘岩溶是处于岷山雪线下部冰缘环境的碳酸盐岩之溶蚀与冻融相互渗合、叠加的岩溶地质类型,具有碳酸盐岩溶场和冰缘岩屑与冰期、间冰期堆积物岩溶场的二元结构。岷山地区大多数碳酸盐岩处于较低的海拔区,在第四纪气温振荡回暖的影响下冰缘岩溶已经衰退,仅残留着早期冰缘岩溶形成的地貌和钙华体,现在的黄龙沟冰缘岩溶因其碳酸盐岩海拔高,仍处在第四纪末期冰川退缩后的冰缘环境,冰缘岩溶地貌和钙华体还在发育,不过现今全球性气温升高和人类的活动对冰缘岩溶都将产生负面影响,以钙华体为核心景观的黄龙、九寨沟风景区的管理部门应予加强监测和保护。  相似文献   

构造叠加晕找盲矿法及研究方法   总被引：5，自引：0，他引：5  

李惠 《地质与勘探》2013,49(1):154-161

构造叠加晕法已在50多个矿山开展了深部盲矿预测应用,取得了显著找矿效果.本文介绍了构造叠加晕找盲矿法的概念及典型矿床深部盲矿预测的构造叠加晕模型的研究思路、内容、工作程序和技术关键,介绍了具体工作方法,包括野外工作布置及特殊的采样方法及要求,构造叠加晕研究中需计算的地球化学参数、图件,构造叠加晕叠加结构的识别依据和方法、建模要求和成矿预测靶位圈定方法.只有掌握构造叠加晕方法技术,才能建立起具有本矿区特色、预测准确性较高的构造叠加晕模型,用模型对本矿区深部及外围预测,才会取得显著找矿效果.  相似文献   

贵州镇远地区钾镁煌斑岩产出控制因素浅析   总被引：6，自引：0，他引：6  

杨光忠 《地质与勘探》2013,49(4):696-702

贵州镇远马坪钾镁煌斑岩为我国发现的第一个含原生金刚石的钾镁煌斑岩,其时代为加里东中期。根据区内当时沉积建造的特点,结合钾镁煌斑岩常包含早期捕虏体的情况,尤其是区内钾镁煌斑岩主要产于加里东期北东向背斜构造翼部拐点范围的事实,认为区内钾镁煌斑岩的侵位应发生在加里东期沉积建造结束褶皱构造开始时刻。加里东构造运动先是沉积建造的塑性变形褶皱造山,岩层能干化后才开始发育大量断裂构造。纵弯褶皱在挤压作用背景下,因褶皱拐点存在拉伸和剪切的应力而构成透入性构造软弱部位,被深部岩浆热力所突破而成为上涌侵位及喷发通道。区域上,四堡期东西向基底断裂构造控制区内钾镁煌斑岩东西向带状分布,而加里东期褶皱及其拐点控制钾镁煌斑岩体(群)的产出,因此金刚石的找矿勘查应主要在有金刚石找矿信息的褶皱构造拐点范围开展。  相似文献   

AuSREM: Australian Seismological Reference Model     

B. L. N. Kennett  M. Salmon 《Australian Journal of Earth Sciences》2013,60(8):1091-1103

Although Australia has been the subject of a wide range of seismological studies, these have concentrated on specific features of the continent at crustal scales and on the broad-scale features in the mantle. The Australian Seismological Reference Model (AuSREM) is designed to bring together the existing information and provide a synthesis in the form of a 3-D model that can provide the basis for future refinement from more detailed studies. The model is grid based with a 0.5° sampling in latitude and longitude and is designed to be fully interpolable, so that properties can be extracted at any point. The crustal component makes use of prior compilations of sediment thicknesses, with cross-checks against recent reflection profiling, and provides P and S wavespeed distributions through the crust. The primary information for P wavespeed comes from refraction profiles, for S wavespeed from receiver function studies, and we are able to use the results of ambient noise tomography to link the point observations into national coverage. Density values are derived using results from gravity interpretations. AuSREM is able to build on a new map of depth to Moho, which has been created using all available information including Moho picks from over 10 000 km of full crustal profiling across the continent. In the upper mantle, the primary source of information comes from seismic surface wave tomography and a representative model has been developed to capture the features of a range of studies. Body-wave studies and regional tomography provide useful constraints on the relationship between P and S wavespeeds. The mantle model extends beyond the continent and so covers a larger area than for the crust. Below 350 km and in the surrounding area, AuSREM is linked to the S40RTS model. Potential applications of the AuSREM model come through the delineation of major structural features in the crust and mantle, and consequent improvements in, for example, earthquake location within the continent and at the nearby plate boundaries.  相似文献   

瞬变电磁法在哈密三岔口西矿段隐伏斑岩型铜矿床的应用     

屈栓柱  谢晓辉  李美英 《新疆地质》2013,(2)

激发极化法是寻找斑岩型矿床的重要手段之一,限于勘查深度较浅和碳质及无用金属硫化物干扰等原因,不能对隐伏矿体进行定位和评价.以新疆哈密三岔口西矿段隐伏斑岩型铜钼矿为例,在分析区域成矿地质背景、前人激电工作成果和岩石物性特征基础上,结合典型斑岩型成矿模式,提出应用瞬变电磁法圈定控矿岩体、岩体顶部及边部的中高电磁感应变化率(中高阻梯级带)部位为成矿有利部位的思路.通过后期钻探验证,发现了规模较大的隐伏斑岩型铜钼矿体,取得较好找矿效果.  相似文献   

甘肃省肃北县红山铁矿外围找矿新进展          下载免费PDF全文

王小红  杨建国  王磊  谢燮 《地质找矿论丛》2013,28(1):118-121

近几年,甘肃省肃北县红山铁矿外围通过地质调查工作,新发现具有进一步工作价值的铁矿点2处,初步评价为大-中型铁矿床。矿体主要赋存于蓟县系平头山组,其产出形态与空间分布受层位及背、向斜构造控制,且深部矿体好于浅部,矿体呈层状、透镜状。勘查区北部罗雅楚山复式向斜内红山铁矿西侧已圈定出长度大于50km的磁异常带,经验证为矿致异常。参照红山铁矿区潜力评价思路及预测成果,该区铁矿资源潜力可达10×108 t以上。通过进一步勘查工作,该地区有望形成大型铁矿资源基地。  相似文献   

浙西北萧山—诸暨地区晚中生代侵入岩地球化学特征及构造意义          下载免费PDF全文

解怀生  张建芳  龚瑞君  许兴苗 《地质找矿论丛》2013,28(3):424-433

浙西北萧山—诸暨地区晚侏罗世末期花岗(石英)闪长岩与早白垩世末期(辉石)闪长岩具有以下地球化学特征:低硅、贫碱、富钙镁铁,弱负铕异常,稀土配分曲线右倾,富集K,Rb,Ba,Th,U等,亏损Nb,Ta等,Sr,Ti亏损不明显。晚侏罗世末期花岗岩与早白垩世末期花岗(斑)岩均具有高硅、富碱、贫钙镁,强负铕异常的特征;晚侏罗世侵入岩具"V"型稀土配分曲线,强富集K,Rb,Th,U等,相对富集Nb,Ta,强亏损Ba,Sr,Ti等特征;早白垩世侵入岩具右倾稀土配分曲线,富集K,Rb,Th,U等,亏损Nb,Ta,Sr,Ti,Ba不亏损等特征。岩石构造地球化学图解分析表明,晚侏罗世末期I-A型花岗岩类成岩构造环境具有从俯冲挤压碰撞作用向后碰撞或后造山作用演化的特征;早白垩世末期(高分异)I型花岗岩类岩石主要与火山-次火山喷发-侵入作用关系密切,成岩构造环境主要与区域伸展作用有关。  相似文献