从电子探针成果进一步探讨菜园子——菱铁矿床的交代特征

贵州西部菱铁矿石富而不杂,是一种优质富铁矿石。前几年,陆续有新的矿产地发现,在我国铁矿总储量中逐渐崭露头角,引起了有关领导部门和地质工作者的重视。 黔西北地区菱铁矿点颇多,达到大中型规模的矿床有三处。水城观音山、赫章铁矿山菱铁矿床从五十年代末就开始了普查、勘探工作。菜园子菱铁矿床是七十年代在赫章铁矿山外围加强地质工作查明的。由于后者储量可观,矿体保存完好,开采条件优越,地质工作程度较高,吸引了不少学者、专家的关注和兴趣。有的矿床学家已将其作为产于碳酸盐岩中的菱     

新疆东天山地区三岔口铜矿床的成因:岩石学、年代学和地球化学证据

三岔口铜矿床位于新疆东天山大南湖岛弧带的东北缘。目前对于三岔口铜矿床的成因类型及成矿年代还存在争议。三岔口铜矿床中赋矿岩体为闪长岩-花岗闪长岩,发育黑云母化、硅化、绢英岩化、青磐岩化等。测得三岔口铜矿床辉钼矿Re-Os年龄为416Ma±6.4 Ma,含矿闪长岩中锆石LA-ICP-MS U-Pb年龄为425 Ma±3.9 Ma,反映该矿床形成于中志留世。矿区内闪长岩-花岗闪长岩w(Na_2O+K_2O)为3.88%~4.68%,A/NCK值均大于1,为铝饱和岩石。岩体贫钾(w(K_2O)0.47%~1.18%)富钠(w(Na_2O)_2.83%~4.23%),w(TiO_2)偏低(0.41%~0.46%),多属于低钾拉斑系列。岩体富集w(Ba)(260×10~(-6)~4 810×10~(-6)),w(Sr)(644×10~(-6)~797×10~(-6))等大离子亲石元素,亏损w(Nb)(2.1×10~(-6)~2.6×10~(-6)),w(Ta)(0.1×10~(-6)),w(Zr)(11.2×10~(-6)~13.1×10~(-6))等高场强元素,具岛弧岩浆岩的特征。岩体富Na贫K,K_2O/Na_2O0.42,且具有高w(Al_2O_3)(≥16.65%),w(SiO_2)(≥61.3%),w(Sr)(≥644×10~(-6))以及较低的w(Y)(≤13.7×10~(-6))和w(Yb)(≤1.41×10~(-6)),具O型埃达克岩的特征,表明三岔口铜矿床形成于俯冲岛弧环境。结合研究区域内铜(钼)矿床的成矿时代及矿床类型,得出东天山地区有三期斑岩型矿床成矿作用:志留纪的三岔口、玉海斑岩型铜矿床,石炭纪的土屋-延东、延西等斑岩型铜矿床,以及三叠纪的东戈壁、白山斑岩型钼矿床。     

对西秦岭泥盆系菱铁矿成因类型的认识及找矿意见

目前在秦岭泥盆系中已发现了多处菱铁矿床及一些有意义的矿化线索。为加快找矿步伐,谈些粗浅认识,共同讨论,谬误之处,请批评指正。秦岭泥盆系菱铁矿成因类型及其基本特征秦岭泥盆系非常发育,广泛分布,属地槽型浅海相含铁建造。随所处古地理环境的差异,形成许多不同类型矿床。氧化环境下形成的当多式(即宁乡式)铁矿,多处都有所见,均以赤铁贫矿为主。在还原条件下形成的大西沟菱铁矿床和磨沟等菱铁矿点已有发现。当多铁矿床中,也见有在过渡环境下形成的菱铁一赤铁矿矿石类型。有些矿床受到后期不同程度的改     

华夏早古生代俯冲作用(Ⅱ):大爽高镁-镁质安山岩新证据

早古生代加里东期造山运动(广西运动)的性质是华南大地构造演化长期争议的重大地质问题.桂东南岑溪大爽一带出露一套早古生代玄武安山岩-安山岩火山岩系.玄武安山岩-安山岩SiO₂含量为47.8%~58.8%,Al₂O₃含量为13.35%~14.25%,CaO含量为3.79%~5.61%,TiO₂含量为0.46%~0.56%,而MgO(4.39%~9.96%)、Ni(141×10-6~210×10-6)和Cr(427×10-6~750×10-6)的含量明显偏高,属钙碱性到过渡系列的高镁-镁质玄武安山岩-安山岩.轻稀土富集,轻重稀土分异明显, δEu弱负异常(0.73~0.92),(La/Yb)_N为3.4~7.9,(La/Sm)_N为3.15~4.95.大离子亲石元素Rb、Ba、Th、U、K、Pb明显富集,高场强元素Nb、Ta、Ti相对亏损,具较低Ti/V(14.7~21.8),表现为高镁-镁质玄武安山岩-安山岩(赞岐岩)的典型特征.镁质安山岩由LA-ICP-MS锆石U-Pb法获得的成岩年龄为443±4 Ma,表明这套火山岩系形成于晚奥陶世-早志留世.上述研究表明,大爽玄武安山岩-安山岩系为晚奥陶世-早志留世形成于洋壳俯冲岛弧弧前环境的高镁-镁质玄武安山岩-安山岩系,其发现为华南扬子与华夏之间存在早古生代洋壳俯冲作用提供了重要证据.      

南秦岭山阳-柞水矿集区大西沟-银硐子铁-银-铅锌-铜矿床磁铁矿地球化学特征:对矿床成因的约束

大西沟-银硐子铁-银-铅锌-铜矿床位于中秦岭晚古生代弧前盆地的山阳-柞水矿集区内,矿床产于中泥盆统大西沟组中,主要发育有与地层产状相同的磁铁矿矿石、含重晶石-菱铁矿的纹层状磁铁矿矿石、磁铁矿-硫化物(黄铁矿、黄铜矿)-石英脉型及块状磁铁矿矿石。通过对4种不同矿化类型矿石的磁铁矿进行电子探针及微量、稀土元素的分析,结果显示不同类型的磁铁矿FeOt含量与Al_2O_3,CoO,MgO,SiO_2质量分数整体上均呈负相关关系;从顺层产出的矿石到块状、脉状及纹层状矿石,磁铁矿的FeOt质量分数(分别为49.65%~84.18%,91.5%8~93.39%,92.69%~93.6%,92.25%~93.39%)在逐渐增加,说明有后期含铁物质的富集。在w(TiO_2)-w(Al_2O_3)-w(MgO+MnO)和w(MgO)-w(TiO_2)-w(Al_2O_3)图解中,大西沟-银硐子矿床的磁铁矿表现出既有热水沉积成因,也有热液成因的特征。同时不同产出状态的磁铁矿均富集Mg,Mn元素,并具有相对较低的Ti(6.82×10~(-6)~451×10~(-6),平均324×10~(-6)),V(11.5×10~(-6)~625×10~(-6),平均378×10~(-6)),Sc(0.78×10~(-6)~1.49×10~(-6),平均1.03×10~(-6))质量分数及Co/Ni,Zn/V和Sn/Ga比值,显示具有热液成因特征,而且从层状矿石到块状、脉状及纹层状矿石,热液作用具有逐渐增强的趋势。不同矿化类型的磁铁矿均表现出明显的负Eu异常,但从层状矿石(δEu为0.32)到块状(δEu为0.72)、脉状(δEu为0.48~0.79)及纹层状矿石(δEu为0.57~0.58),负Eu异常逐渐减弱,说明整个成矿环境的氧化性在逐渐增强,但总体仍处于还原环境。因此,研究表明大西沟-银硐子矿床在成矿作用过程中受到后期热液活动影响,成矿作用发生于氧化性增强,还原性减弱的成矿环境。     

安徽庐枞盆地龙桥铁矿床中钴的赋存状态和空间分布规律

中国东部的长江中下游、莱芜、邯邢和临汾等矿集区中发育大量的矽卡岩型铁矿床,其中普遍伴生钴,部分矿床估算伴生钴资源量大于1万t,达到中型钴矿床的规模。已有研究表明,中国东部富钴矽卡岩型铁矿床的成矿时代相同,成矿特征相似,均为中国东部130Ma大规模成矿作用的产物,反映较大规模的铁钴成矿作用受统一的动力学背景控制。钴与其他伴生组分一样,其工业价值主要不取决于矿石中钴的含量,而取决于钴的赋存状态,因此开展矽卡岩型铁矿床中钴的赋存状态和分布规律研究具有重要的理论和实践意义。龙桥矽卡岩型铁矿床位于长江中下游成矿带,是目前发现的成矿带内伴生钴含量最高的矿床。矿床主矿体长1000m,成矿岩体位于矿体中部,黄铁矿分布范围广,距离岩体中心不同距离均有分布,是研究矽卡岩型铁矿床中钴赋存状态和空间分布规律的理想对象。本次研究在龙桥铁矿床勘探巷道-370m平面自西向东采集了9件含黄铁矿样品,黄铁矿主要呈浸染状-细脉状交代磁铁矿。研究表明,龙桥铁矿床中钴主要赋存在黄铁矿和磁铁矿中,其次为独立钴矿物(主要为辉砷钴矿)。黄铁矿的LA-ICP-MS微区微量元素分析结果表明,龙桥黄铁矿中Co(0.019×10~(-6)～5639×10~(-6))、Ni(0.025×10~(-6)～5798×10~(-6))和As(0.46×10~(-6)～14526×10~(-6))的含量均具有较大的变化范围,黄铁矿总体上具有边缘富钴、核部贫钴的特征,黄铁矿边部的钴含量是核部的100～1000倍。通过对LA-ICP-MS测试数据以及时间分辨率剖面的逐一对比,推测Co主要以类质同象形式替代Fe进入黄铁矿晶格。由于钴在黄铁矿中分布极不均匀,不同空间位置采集的黄铁矿样品中Co含量平均值和变化范围没有明显规律。本文通过类比,提出中国东部矽卡岩型铁矿床中钴矿物可能是普遍存在的,但以前受限于分析测试手段未能发现;如何在选矿过程中分离富集钴矿物和富钴黄铁矿,是矽卡岩型铁矿床硫精粉中钴回收利用的关键。     

铜陵荷花山铅锌矿区闪长岩类LA-ICP-MS锆石U-Pb年代学、地球化学特征及地质意义

荷花山铅锌矿床是长江中下游成矿带铜陵矿集区内新发现的大型铅锌矿床,该矿床矿体呈似层状主要赋存于三叠系南陵湖组下段瘤状灰岩中。矿区内经钻孔揭露,有两种岩性的闪长岩类,分别为矿区西侧的闪长岩体和东侧的石英闪长岩体。锆石LA-ICP-MS U-Pb年代学分析得出这两个岩体的年龄分别为133.0±2.1Ma和130.1±1.7Ma,表明其形成时代为早白垩世。全岩地球化学分析显示,荷花山闪长岩类表现为Si O256%(56.17%~65.90%),Al2O3≥15%(15.10%~17.22%),Mg O3%(0.84%~2.22%),Yb1.9×10~(-6)(1.35×10~(-6)~1.64×10~(-6)),Y18×10~(-6)(11.60×10~(-6)~15.70×10~(-6)),无明显的Eu异常等特征,具有与典型的埃达克岩相似的特征,微量元素判别图解表明荷花山矿区闪长岩类岩浆来源于幔源岩浆和加厚下地壳埃达克岩浆的混合,是铜陵地区晚期岩浆活动的代表;构造判别图解表明荷花山闪长岩类形成于相对挤压或者挤压向拉张过渡的岩石构造环境,其形成与古太平洋板块的俯冲有关,可能预示着铜陵地区存在130Ma左右的铅锌矿化事件。     

贵州西部香炉山式铁矿成矿控制因素初步研究

香炉山式铁矿是近年地质勘查工作中在贵州西部威宁-水城-赫章地区晚二叠世峨眉山玄武岩组和宣威组之间发现的新类型铁矿床。在矿床成因上,该矿床既不同于海相的沉积型铁矿床,也不同于陆相的古风化壳矿床,而是兼有二者的特征,属于玄武岩古风化壳-沉积(堆积)型铁矿床。通过野外观察、岩矿石分析测试、岩矿石鉴定、电子探针微区分析等手段对含铁岩系和矿石特征进行研究发现,矿石具有定向排列的火山碎屑、渗流管孔、姜结仁等典型结构构造。初步认为,香炉山式铁矿的形成除具有特殊的成矿背景外,还受到成矿物质来源、岩相古地理、古纬度、古气候、古生物生态、古风化作用等诸多因素的综合控制,是峨眉山大火成岩省外生成矿作用的典型实例。     

东昆仑石头坑德镁铁-超镁铁质岩体矿物学特征及成矿潜力分析

位于东昆仑造山带之昆中带内部的石头坑德镁铁-超镁铁质岩体,分别由辉长岩相、辉石岩相和橄榄岩相的多种岩石类型组成。野外地质资料表明各岩相间的先后侵位顺序为辉长岩相→辉石岩相→橄榄岩相。本次研究表明石头坑德岩体尖晶石Ni的平均含量为258×10~(-6);橄榄石Fo=81~86,为贵橄榄石,Ni含量471×10~(-6)~2 279×10~(-6),平均为1 153×10~(-6);斜方辉石的En=80.35~83.89,平均82.51。根据Mg-Fe在结晶相橄榄石和熔体之间的分配系数,利用Fo值最高的橄榄石,得到其原生岩浆MgO=10.5%,属高镁玄武质岩浆。该岩体由上地幔橄榄岩11.2%~14.0%的部分熔融作用形成的。通过对石头坑德岩体的部分熔融程度、原生岩浆、构造标志、岩石组合、直接矿化标志及矿物组合、橄榄石Ni含量及Fo的研究表明,石头坑德镁铁-超镁铁质岩体具有形成铜镍硫化物矿床的有利条件,东昆仑造山带是重要的成镍远景区。     

内蒙古梅劳特乌拉蛇绿岩中早二叠世高镁闪长岩的发现及洋内俯冲作用

内蒙古梅劳特乌拉SSZ型蛇绿岩中,新发现了早二叠世巴嘎哈尔高镁闪长岩。该闪长岩位于贺根山缝合带内。锆石LA-ICP-MS U-Pb测年表明,巴嘎哈尔闪长岩的侵位年龄为(282±2)Ma,其形成时代为早二叠世。该岩石高镁,MgO含量5.00%~10.94%,Mg#值54~74;SiO_2含量53.52%~58.64%,Al_2O_3含量13.48%~14.98%,Na_2O含量1.36%~3.59%;贫钾,K_2O含量0.48%~1.61%;贫TiO_2(0.28%~0.76%)和P_2O_5(0.080%~0.160%);富Cr(75.00×10~(-6)~555.90×10~(-6))和Ni(26.20×10~(-6)~228.40×10~(-6));富集K、Rb和Sr等大离子亲石元素,亏损Nb、Ta、Zr、Ti和P等高场强元素;稀土元素总量较低(25.16×10~(-6)~83.57×10~(-6)),稀土曲线为略右倾的平坦型。该岩石具有高镁闪长岩的地球化学特征,与赞岐岩相类似,属于俯冲带岛弧型岩浆岩。结合其与梅劳特乌拉SSZ型蛇绿岩中玻安岩和埃达克岩的岩石组合时空分布特征,表明古亚洲洋贺根山洋盆在早二叠世可能仍然处于大洋俯冲消减状态。该高镁闪长岩可能为俯冲洋壳+俯冲深积物来源的硅质熔体交代上覆地幔楔使其部分熔融的产物。     

摩擦桩基桩土间极限摩阻力取值问题探讨

通过对广珠东线高速公路横沥大桥的试桩及土体的工程地质条件分析,总结出影响摩擦桩基桩土间极限摩阻力取值的一般问题以及解决问题的方法和措施。     

从榴辉岩与围岩的关系论苏鲁榴辉岩的形成与折返

位于华北和扬子两板块碰撞带中的苏鲁榴辉岩形成的温压条件不但是超高压，而且是高温。榴辉岩的PTt轨迹表明其为陆-陆磁撞俯冲带的产物。榴辉岩的区域性围岩花岗质片麻岩为新元古代同碰撞期花岗岩，榴辉岩及其他直接围岩皆呈包体存在于其中，并见新元古代花岗岩呈脉状侵入榴辉岩包体中。区域性围岩新元古代花岗岩的锆石中发现有柯石英、绿辉石等包裹体，表明新元古代花岗岩的组成物质也经受过超高压变质作用，且榴辉岩与围岩新元古代花岗岩的锆石U-Pb体系同位素年龄基本相同。但新元古代花岗岩所记录的变质作用和变形作用期次（或阶段）却少于榴辉岩。椐上述可得如下推断：超高压榴辉岩与新元古代花岗岩岩浆是同时在碰撞带底部（俯冲板块前部）形成的；榴辉岩的第一折返阶段是由新元古代花岗岩岩浆携带上升的，其第二折返阶段是和新元古代花岗岩一起由逆冲及区域性隆起而上升，遭受剥蚀。     

The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads

In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.     

某高速公路下伏煤矿采空区稳定性分析

在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。      

混凝剂处理钻井废泥浆液的研究

通过烧杯搅拌实验对混凝剂处理钻井废泥浆液进行研究,从混凝剂适应p H值范围、混凝效果、沉降速度三方面研究比较,找出一种较为理想的混凝剂,并分析了影响混凝剂性能的主要因素,确定了混凝剂的最佳投放剂量。      

黄河源区水环境变化及黄河出现冬季断流的原因

自1954年有水文观测资料以来，黄河曾在青海省玛多县黄河沿水文站发生过3次断流。本文在分析黄河源区水环境特征及其影响因素的基础上指出，鄂陵湖、扎陵湖的环湖融区调节能力低，当遇到连续干旱、冬季其调节水量不足以维系黄河径流时便会发生断流，这是断流的主因。湖水位降低、开采沙金、过度放牧等自然和人为因素也会对黄河发生断流产生影响。鄂陵湖口附近黄河上修建的水电站开始蓄水，提高了两湖及环湖融区的调节能力，今后黄河冬季出现断流的可能性将大为降低。     

Unity of the national and the international in the socio-cultural development of the peoples of the USSR

International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.     

Artemia in the Salt Lakes of Russia:the Productivity of Populations,the Reserves of the Cysts and the Fisheries

正Artemia cysts are an extremely important component of aquaculture diets.It is well established that the cultivation of fish and shellfish derive substantial health and growth advantages when Artemia are included in the diets of the     

天山南坡科其喀尔冰川表碛区小气候特征研究

利用天山南坡科其喀尔冰川3号观测站2009年全年的气象观测资料,分析研究了科其喀尔冰川表碛区的小气候特征. 结果表明：总辐射和净辐射夏秋季较高、冬春季较低;反射辐射和地表反照率反之. 与其他地区不同,该区主要受积雪物理性质和下垫面状况的影响,冬春季地表反照率日变化表现为由大到小的变化过程,夏秋季表现为倒U型. 温度年变化表现为夏秋季高、冬春季低,最高月均值出现在8月,为9.4℃,最低月均值出现在1月,为-9.6℃. 受山谷风和冰川风的影响,全年的风向以西北风和西北偏西风为主,风向的日变化以11：00为界发生转向. 受降水和冰川消融等的影响,比湿夏秋季月均值较大,冬春季月均值较小.     

Climate: Is the past the key to the future?

 The climate of the Holocene is not well suited to be the baseline for the climate of the planet. It is an interglacial, a state typical of only 10% of the past few million years. It is a time of relative sea-level stability after a rapid 130-m rise from the lowstand during the last glacial maximum. Physical geologic processes are operating at unusual rates and much of the geochemical system is not in a steady state. During most of the Phanerozoic there have been no continental ice sheets on the earth, and the planet’s meridional temperature gradient has been much less than it is presently. Major factors influencing climate are insolation, greenhouse gases, paleogeography, and vegetation; the first two are discussed in this paper. Changes in the earth’s orbital parameters affect the amount of radiation received from the sun at different latitudes over the course of the year. During the last climate cycle, the waxing and waning of the northern hemisphere continental ice sheets closely followed the changes in summer insolation at the latitude of the northern hemisphere polar circle. The overall intensity of insolation in the northern hemisphere is governed by the precession of the earth’s axis of rotation, and the precession and ellipticity of the earth’s orbit. At the polar circle a meridional minimum of summer insolation becomes alternately more and less pronounced as the obliquity of the earth’s axis of rotation changes. Feedback processes amplify the insolation signal. Greenhouse gases (H₂O, CO₂, CH₄, CFCs) modulate the insolation-driven climate. The atmospheric content of CO₂ during the last glacial maximum was approximately 30% less than during the present interglacial. A variety of possible causes for this change have been postulated. The present burning of fossil fuels, deforestation, and cement manufacture since the beginning of the industrial revolution have added CO₂ to the atmosphere when its content due to glacial-interglacial variation was already at a maximum. Anthropogenic activity has increased the CO₂ content of the atmosphere to 130% of its previous Holocene level, probably higher than at any time during the past few million years. During the Late Cretaceous the atmospheric CO₂ content was probably about four times that of the present, the level to which it may rise at the end of the next century. The results of a Campanian (80 Ma) climate simulation suggest that the positive feedback between CO₂ and another important greenhouse gas, H₂O, raised the earth’s temperature to a level where latent heat transport became much more significant than it is presently, and operated efficiently at all latitudes. Atmospheric high- and low-pressure systems were as much the result of variations in the vapor content of the air as of temperature differences. In our present state of knowledge, future climate change is unpredictable because by adding CO₂ to the atmosphere we are forcing the climate toward a “greenhouse” mode when it is accustomed to moving between the glacial–interglacial “icehouse” states that reflect the waxing and waning of ice sheets. At the same time we are replacing freely transpiring C3 plants with water-conserving C4 plants, producing a global vegetation complex that has no past analog. The past climates of the earth cannot be used as a direct guide to what may occur in the future. To understand what may happen in the future we must learn about the first principles of physics and chemistry related to the earth’s system. The fundamental mechanisms of the climate system are best explored in simulations of the earth’s ancient extreme climates. Received: 7 November 1996/Accepted: 23 January 1997