四川牦牛坪稀土矿床碳酸岩-正长岩成因及成矿流体来源

四川耗牛坪稀土矿床是中国仅次于白云鄂博的第二大原生轻稀土矿床。矿区碳酸岩-正长岩与REE矿化时空上密切共生。本论文系统分析了矿区碳酸岩-正长岩的主要元素、微量元素、REE、PGE和C、O、Sr、Nd、Pb同位素组成，探讨了碳酸岩-正长岩的地慢源区特征及两类岩石的成因联系；结合矿区主要脉石矿物萤石和其它岩浆岩的REE、Sl-Nd-Pb同位素、流体包裹体地球化学，探讨了REE成矿流体的来源，初步建立了REE成矿模式。取得的主要认识有：1，系统研究了耗牛坪REE矿床碳酸岩-正长岩的地球化学特征，揭示了两者的地慢源区特征和成因联系。受陆内俯冲作用的影响，具有EMZ指纹的地壳物质俯冲交代具EMI特征的岩石圈地慢，形成碳酸岩一正长岩的初始地慢，该地慢经低程度部份熔融作用形成富COZ硅酸岩熔体—碳酸岩-正长岩原始岩浆，该熔体在演化过程中发生液态不混溶作用形成碳酸岩和正长岩。2．通过对耗牛坪REE矿床碳酸岩PGE地球化学的研究，发现碳酸岩具有携带PGE的能力，其PGE配分模式与西藏大竹卡方辉橄榄岩相似。初步认为本区碳酸岩中的PGE可能主要来源于俯冲或地鳗交代的流体，除硫化物外，合金或挥发份都可能影响碳酸岩PGE的配分模式。3．萤石是耗牛坪REE矿床重要的脉石矿物之一，其形成贯穿了整个成矿过程。根据REE地球化学参数将萤石分为LREE富集型、LREE平坦埠和LREE亏损型。三种REE类型的萤石具有相似的Sr、Nd、Pb同位素组成，为同源不同阶段的产物，形成顺序为LREE富集型-LREE平坦型-LREE亏损型。4．萤石的Sr、Nd、Pb同位素组成与矿区碳酸岩-正长岩相近，明显不同于花岗岩；早期萤石的REE地球化学特征也与碳酸岩-正长岩相似，与花岗岩、流纹岩和玄武岩存在差别；在萤石中发现了流体-熔融包裹体。这些特征均表明牡牛坪REE矿床成矿流体主要来源于碳酸岩-正长岩熔体，矿床为地幔流体成矿的产物。

中元古代昆阳群Fe-Cu-REE矿床地球化学研究-以武定迤纳厂矿床为例

稀土元素成矿与地壳的构造运动密切相关，稀土在中元古代具有大规模暴发性成矿特征。云南武定迤纳厂稀土铁铜矿床为昆阳群因民组出现稀土富集成矿的典型代表。本论文选择迤纳厂矿床为主要研究对象，系统研究矿床不同类型岩（矿）石和矿物的稀土元素地球化学特征，探讨富稀土的成矿流体、成矿物质来源和稀土元素成矿时代，揭示昆阳裂谷初期因民组稀土元素富集的地球化学机制。主要认识如下：1、迤纳厂矿床产于昆阳裂谷初期形成的禄丰一武定火山断陷盆地中。早中元古界昆阳群分布于绿汁江岩石圈断裂和小江一易门断裂的夹持地带，呈狭长状展布。迤纳厂矿床赋矿地层为昆阳群因民组上段的硅质白云岩和碱性火山岩（粗面安山岩）。矿体产出形态和矿石的结构构造等均显示矿体与赋矿地层同沉积特征；出现独立矿物氟碳饰矿、独居石及褐帘石，磷灰石、萤石、菱铁矿等矿物中也含有一定量的稀土，沿矿体走向和垂向稀土元素变化不大。2、矿体顶、底板围岩（石榴石黑云母片岩、钠长黑云母片岩等）的原岩为碱性火山岩（粗面安山岩），相对富集大离子亲石元素Ba、Cs、Rb、K、LRE日及贫Zr、Sr、Ti、Hf、HEE，为早元古代末期一中元古代早期交代富集地慢低程度部分熔融所形成的碱性火山岩。矿石稀土总量高（645-4443）×10-6，强烈富集轻稀土（（La/Tb）N＝17.3-81.1），稀土元素分布特征明显不同于矿区正常沉积的硅质白云岩和后期侵入的钠长石英斑岩及火山角砾岩，而与矿体顶、底板碱性火山岩中稀土元素配分特征基本一致，暗示稀土成矿物质来源与碱性火山岩有密切的关系；3、矿石中微量元素组合及变化特征与现代海底正在喷出的热液和热液沉积物中元素组合有较大的可比性，明显不同与火成碳酸岩型稀土矿床中的特征元素组合；在微量元素判别图解（Al-Fe-Mn、Fe／Ti-Al／（Al+Fe＋Mn）、U-Th、Y-P2O5等）中，逸纳厂矿石均投影在热水沉积区，矿石的Y／Ho值与黑烟囱值接近，表明成矿流体为高温、还原性质，稀土成矿可能以热水沉积作用方式为主；4、对矿石中主要矿物萤石、菱铁矿、磁铁矿、石英、方解石的稀土元素特征研究表明，矿石沉积时不同矿物中稀土元素分布特征基本相同，主要受成矿流体中稀土分布特征制约。而后期变质作用形成的矿物，其稀土元素分布主要受矿物晶体结构控制。同期成矿流体从早期到晚期（块状矿石→条带状矿石），轻重稀土分异变小，稀土总量增加，条带状矿石中稀土含量最高；矿石黄铜矿6345值变化在一任3％0到2g％。范围，显示慢源硫特征；菱铁矿6r3C（8％-9.1%）、δ18O（-11.17%-15.37）‰指示成矿流体具岩浆来源和有机质的脱梭酸分解作用参与；成矿流体中稀土元素可能主要以（RE（CO3）3F）4-、（既（CO3）3F2）、（RE（F，Cl万等形式迁移，当温度降低时沉淀出氟碳饰矿等稀土矿物；5、矿石和萤石单矿物 Sm-Nd等时线年龄分别为1621士110Ma和15：38士43Ma，与矿区碱性火山岩错石的U-Pb年龄1676Ma、因民组顶部石英正长斑岩的错石U-P1。年龄1685Ma基本一致，也与因民组地层年龄1765M。较为接近，反映成矿时代为早元古代晚期和中元古代早期：这一时间也与一早元古代晚期一中元古代早期昆阳裂谷初始裂陷阶段，大量来自于地幔的碱性火山岩喷发事件相吻合。矿石。Nd（t）:-2.87-3.60，萤石单矿物εNd（t）：-3.93-5.90，变化范围较窄并全为负值，接近0，指示源区为富集地幔。同时结合矿床形成的构造一地质环境及矿体产出的地质形态，认为逛纳厂稀土铁铜矿床可能是在昆阳裂谷初期，在碱性火山岩浆喷发的间歇期，来自地幔富稀土、挥发份的成矿流体由火山喷流一同生沉积方式形成的矿床。6、昆阳群因民组地层中出现的稀土富集、成矿与我国的白云鄂博稀土REE-Fe-Nb超大型矿一床和澳大利亚的olympic Dam Cu-U-Au-Ag-REE超大型矿床，在成矿时代、产出大地构造背景、成矿物质来源等方面具有较大的相似性，均体现成矿受控于中元古代1.5Ga超大陆聚合前或随后裂解初始阶段伴随的非造山型碱性岩浆或热液作用，稀土来源于超大陆拼合前因板块俯冲交代而形成的富集地幔。

氟、氯对热液钨、铜成矿的制约-以江西德兴铜矿、大吉山钨矿为例

矿化剂在热液矿床成矿过程中的重要作用一直为人们所关注，矿化剂地球化学行为直接影响成矿元素的富集成矿，不同的矿化剂元素可能对金属成矿具有一定的专属性。本文以著名的江西德兴铜厂超大型斑岩铜矿床和大吉山钨矿床作为研究对象，研究F、Cl与W、Cu成矿的关系。主要的认识如下：（1）F在花岗质岩浆中，可以降低岩浆的粘度、密度、固液相线温度、改变熔体结构，而Cl对熔体结构没有多大的影响。F在流体一花岗质熔体相间，绝大多数配分系数小于1.0，趋向于熔体相中配分，DF随体系中F浓度的升高而增加。Cl在流体一花岗质熔体相间的配分系数均大于1.0，且Dc1 随体系中Cl浓度的升高而增大·Cl强烈地趋向富集于流体相中。（2）Cu在流体一花岗质熔体作用过程中，铜总趋向于流体相中分布（DCu都大于1）。特别是在富Cl流体中Cu浓度较高，说明在富含Cl的热液流体能够从共存的熔体中活化迁移出大量的 Cu，S的加入DCu有降低的趋势。钨趋向于熔体相中富集，其配分系数大多小于1.0。（3）德兴铜厂花岗闪长斑岩属钙碱性系列岩石属I型花岗岩类，具有埃达克岩的特征。岩浆来源于深部，在结晶演化过程中发生了围岩物质的混染，这种高铜含量围岩的混染使成矿物质在岩浆中得到富集，有利于铜的活化、迁移。在铜厂岩体不同的蚀变带中，SiO2、K2O、Cu、Mo等从新鲜斑岩甚至弱蚀变带中带出，而在强蚀变带强烈富集，Cl同样有在强蚀变岩石中富集的趋势；而Na2O、Fe从斑岩体中带出，进入流体相中，流体中大量Fe的存在，有利于铜的沉淀、富集成矿。（4）德兴铜厂斑岩体微量元素和稀土元素地球化学特征表明，该岩体发生了流体一熔体作用，分异出来的流体是一种相对富氯的流体，同时成矿流体的流向是从岩体中心向接触带方向流动。（5）大吉山花岗岩具有高SiO2、A/CNK值，显示过铝质特点。黑云母花岗岩是壳源花岗岩但又受到慢源岩浆或慢源流体的影响。随着花岗岩的演化（从I→II→III）SiO2、K2O＋Na2O逐渐增加，ΣFe、Al2O3、CaO、F含量降低，为成矿提供了大量的矿化剂（F）和沉淀剂（Fe、Ca）。Eu负异常从I至III阶段花岗岩逐渐加强，表明该岩浆经历了高度的分异演化。（6）大吉山花岗岩类稀土元素具有“四重效应”配分的特点以及微量元素对玲Rb、Y/Ho、Zr/Hf以及Nb／Ta发生明显分异，暗示在花岗岩岩浆的演化过程中，经历了充分的流体一熔体作用，同时分异出大量富含F、W等矿化剂元素和成矿元素的热液流体，致使钨矿的形成。大吉山石英脉型钨矿的成矿年龄大约在155 Ma。（7）通过对成矿流体和花岗质岩石黑云母、白云母中卤素相对逸度的研究（log(H2O/fHCl）fluid、log（fHF/fHCl）fluid）发现，铜厂斑岩型铜矿床的成矿体系是相对富氯体系，而大吉山石英脉型钨矿床成矿体系相对富氟，同时氟可能主要迁移W、Sn、Nb、Ta等金属元素。（8）结合斑岩型铜矿床成矿流体特征，铜主要以C1的络合物形式存在和迁移，迁移形式主要是CuCl0、CuCl2等。石英脉型钨矿床中，钨主要以钨酸、钨酸盐及其离解形式存在和迁移，如WO42-、HWO4-、NaHWO4、Naw伍．等；在高度富氟的成矿流体中，钨的氟氧络合物（如WO3F-，WO2F42-等）对钨迁移也具有重要的作用。因此，不同矿化剂类型具有一定的成矿专属性，热液铜矿床主要与Cl、S有 关，而热液钨矿床大多与F有关。

东川稀矿山式铜矿地球化学研究

稀矿山式铜矿是指赋存在昆阳群因民组地层中的铜铁矿床，其大地构造背景属于元古代裂谷带，大陆裂谷是超大型铜等多金属矿形成和分布的有利环境，在裂谷下部常发育异常地慢和岩浆源，裂谷空间上的多层次性使矿床具有明显垂向分带特征，其演化时间的长期性、脉动性和继承性便于多期成矿作用相互叠加、矿质的高度聚集。稀矿山式铜矿以落雪矿区稀矿山矿段最为典型，主要分布在因民落雪大乔地一稀矿山、滥山、磨子山，滥泥坪6-4巷、白锡腊和拖布卡地区。该类矿床广布于康滇地轴南段东川、武定一罗茨、元江、易门狮子山、金沙江南岸的花生坪、红门厂等地，已知中型铜矿床1处（稀矿山）、中型铁矿床2处（鹅头厂、笔架山）、小型铜（铁）矿床多处，上世纪90年代易门狮子山该类矿床的发现，表明该类矿床在东川-易门具找矿潜在远景。本文通过对东川矿区稀矿山式铜矿的常量元素、微量元素、包裹体、同位素及同位素定年等地球化学研究，获得以下认识：1．东川矿区地层（包括其下覆基底）和晋宁期碱基性岩中Cu等成矿元素背景值较高，且在蚀变过程中均能析出Cu等成矿元素。矿床中Cu等成矿物质来源复杂，以深源为主，部分来源于地层（因民组紫色层和落雪组白云岩）及基底地层：矿区内的退色蚀变作用可能是混合流体碱质交代改造作用的结果，对铜矿形成影响明显，是铜矿化的标志；2．该类矿床成矿流体属于中高温、中高盐度、高密度Na，（K＋）Ca2+-SO42-（Cl-）型，以深部岩浆水为主，混有大量海水和变质水。矿床中发现了富NZ包裹体，可能是矿床形成时，深大断裂活动、碱基性岩浆带来地球深部（上地慢和下地壳）物质并形成的成矿流体，在氧化一去挥发分作用过程中所形成；3．铁矿体被铜矿体包围，铁矿石被铜矿细脉穿插，说明铜矿化的形成晚于铁矿化。黄铜矿单矿物的Re-05同位素年龄研究表明其成矿年龄为826士230Ma，接近矿区碱基性岩年龄，与昆阳裂谷内其它类型铜矿成矿时代相当，均属于晋宁-澄江期；4．东川矿区晋宁一澄江期碱基性岩侵入活动明显，常作为因民组复杂角砾岩胶结物和岩脉（体）产出，多分布于深大断裂及其派生的次级构造附近，明显受南北向小江深大断裂走滑运动引起的右行旋扭及其派生构造控制，与“落因破碎带”和“铜矿分布”较吻合，均为“Z”字形。表明东川矿区铜矿形成与深大断裂及其派生次级构造和，宁-澄江期碱基性岩侵入活动关系密切；5．昆阳裂谷内的多数铜矿同位素成矿年龄多集中在9.0亿-6.5亿年之间，属于晋宁－澄江期，与Redina大陆裂解时限相当。表明裂谷内铜矿床的形成可能与Rodinia大陆裂解有关。因此，总结东川稀矿山式铜矿成矿模式为沉积（Fe、Cu）-热液叠加（Cu）改造：晋宁-澄江期，小江深大断裂发生走滑运动，在东川矿区造成右行旋扭及其派生构造，形成“Z”，字形落因破碎带，同时来自深源（下地壳或上地慢）碱基性岩浆侵入，不仅带来了大量Cu等成矿物质，更重要的是提供了热源，促使地层水（落雪组白云岩和因民组紫色层）循环，与富碱（Na和K）岩浆水混合，形成富碱中高温高盐度流体。因民组紫色层与其底部角砾岩接触带，具有较高的空隙度和渗透率，有利于成矿流体的运移和成矿。在这种混合流体作用下，地层中Cu等成矿物质析出，叠加改造了初始铜矿化最终形成稀矿山式铜矿。

磷矿的形成与Rodinia超大陆裂解、生物爆发的关系-以贵州瓮安、开阳、织金磷矿床为例

贵州省分布有两期大型磷矿：震旦纪陡山沱期和早寒武纪梅树村时期。在这两期磷矿中分别发育有瓮安生物群和小壳动物梅树村生物群，这两个生物群代表了生命早期演化过程中的两次爆发事件。由此推测磷矿的形成可能与生物的爆发存在某种联系。另外，已有研究表明，磷矿层下伏的南沱冰碳岩和上覆的灯影帽碳酸盐的形成都与晚元古代末的Rodini。超大陆裂解相关，那么沉积于它们之间的磷矿也可能与Rodinia超大陆裂解相关联。研究磷矿形成、Rodinia超大陆裂解及生物爆发三者之间的关系对揭示磷矿的物质来源、成矿环境、构造条件、成因机制等有重要的理论意义；对解决全球范围晚元古代地层、几次生物爆发事件和．冰川事件的对比问题等有极其重要的理论和实际意义。本文以晚元古代陡山沱期（瓮安、开阳）和早寒武纪（织金）磷矿床为研究对象，借鉴岩相学、古生物学、元素地球化学、同位素地球化学、有机地球化学及Sm-Nd、Rb-Sr同位素定年等方法，讨论磷矿的形成与Rodini。超大陆裂解、生物爆发之间的关系。论文主要获得了以下几个方面的认识：研究了三个矿床的主要地质特征，表明寒武纪织金磷矿床的磷品位低于陡山沱期磷矿床。瓮安、织金磷矿床形成于氧化带环境，而开阳磷矿床形成于亚氧化带环境。确定了三个矿床的成矿时代。同位素年代学得出陡山沱组磷矿床形成年龄为583±19Ma（Sm-Nd法）、588±8.6Ma和582±7.7Ma（Rb-Sr法），寒武纪磷矿床的形成年龄为542±23Ma（Sm-Nd法）和541±12Ma（Rb-Sr法）。震旦纪陡山沱期和寒武纪梅树村期磷矿床的形成时代与华南地块从Rodinia超大陆中裂解漂移出来的时间（600Ma～550Ma、540Ma）相耦合，为Rodinia超大陆裂解事件与磷矿床的形成存在密切成因联系提供了年代学方面的证据。对三个磷矿床进行的大量地质地球化学研究表明：Rodinia超大陆裂解为磷矿的形成提供了热液源和慢源成矿物质，并造成了大规模的低温热液成矿作用。研究了发育于陡山沱组和寒武纪含磷地层中的瓮安生物群和梅树村小壳生物群爆发的原因，表明Rodini。超大陆裂解造成了两次生物大爆发。超大陆裂解引发地球化学异常，导致了生物的大发展。讨论了地层中生物与磷的关系。地质证据、伴生微量元素证据、磷灰石矿物地球化学证据及有机地球化学证据表明，生物有机质直接或间接地参与了成磷作用。其中生物直接参与成磷作用主要发生在成矿过程的磷质吸取阶段，同时也见于地球化学富集阶段还原型细菌活跃的成岩带中；有机质间接成磷作用主要发生在磷块岩成矿过程的地球化学富集阶段和物理富集阶段。总结了磷矿的形成与Rodinia超大陆裂解、生物爆发之间的关系，Rodinia超大陆裂解为磷矿的形成提供了热液源和慢源的成矿物质；同时引发了生物的大爆发，而生物大爆发则促进了成矿物质的超常聚集和大规模成矿。

地幔去气与铀成矿的关系——以江西相山火山岩型铀矿为例

江西相山铀矿床，位于中生代赣一杭火山岩带相山火山塌陷盆地内，是中国目前发现的最大的火山岩型铀矿床，其独特的成矿环境及成矿机理为国内外地质界所瞩目。本论文主要运用岩石学、构造学寸流体包裹体地球化学、同位素地球化学、热力学方法，从相山铀矿床的成矿构造演化、成矿流体、岩石蚀变特征、成矿物质同位素组成特征以及热力学计算等方面对地慢去气特征、过程以及其与铀矿化的关系进行了详细的研究。本研究取得了以下主要认识：1、构造活动对成矿过程起到重要作用。区域深大断裂构造、慢源岩浆活动和碱交代蚀变作用，是相山铀矿田地（量去气作用产生的地慢流体参与成矿作用的有利条件和证据。2、热力学计算表明成矿期前成矿热液pH值为9．50，呈碱性；成矿期前，UO2（CO3）22-、UO2（Coa）44-两种形式迁移的U占总U的99.96％，即矿床中成矿期前的铀主要是以这两种形式迁移的。3、氦一氢同位素研究表明，相山铀矿床的成矿流体由富CO2和3He的慢源流体与贫CO2的大气成因流体混合而成。相山铀矿床成矿热液中的CO2总体属于慢源碳，主要是由地慢或分布在铀矿床中的漫源基性脉岩提供的，而且大部分是在地壳拉张作用期间由地慢去气作用产生而上升形成了成矿热液。4、相山铀矿田成矿期前的流体包裹体中气泡较大，气体含量较高，表明包裹体捕获时压力较大；成矿期和成矿后的包裹体中气泡较小，并存在大量的纯气相包体，通过激光拉曼分析测得的物相峰值极低，表明包体中所包含组分的含量极低。而且大量成矿期纯气相包体的发现也说明其是在去气过程中捕获的从成矿热液中释放出的气体。从成矿期前到成矿期后，CO2含量减小的变化。也说明了成矿作用中发生了减压去气过程。5、在铀成矿过程中，共发生了两次去气作用。第一次地慢去气作用产生并把C仇带入到成矿热液中，第二次成矿流体去气作用正好相反把CO2从成矿热液中带出。地慢去气作用产生富CO2+H2O的地慢流体运移到地壳浅部与大气降水混和，富含矿化剂的成矿溶液由此可以有效地从赋矿围岩（中酸性火山岩和盆地基底地层）中萃取出成矿所需的U。第一次地慢去气作用产生的富CO2+H2O的地慢流体为成矿提供了最充足的矿化剂（CO2），是成矿作用得以发生的最基本最重要的条件。

贵州贞丰县水银洞金矿床成矿特征和金的超常富集机制研究

黔西南地区是我国最重要的卡林型金矿床集中区，在该区卡林型金矿床具有断裂型和层控型两大类。断裂型金矿床产于高角度压扭性断裂中，赋矿层位一般为中、下三叠统地层，容矿岩石主要是泥质粉砂岩和粉砂质泥岩。层控型金矿床主要产于上二叠统地层中，容矿岩石主要是不纯的生物碎屑灰岩，背斜控矿明显。由于目前断裂型金矿一研究程度高，而层控型金矿研究程度低．近年来在层控型金矿床中一些大型和特大型矿床以及富矿体和高拮位矿石的新发现，使层控型金矿床成为黔西南卡林型金矿床的重要和具有特征的类型。因此，作者选择了水银洞金矿床这个大型较富的一卜林型金矿床进行系统研究，对其成矿特征和金的超常富集机制获得以下认识：1．金矿床受构造与有利岩性组合的双重控制。金矿床位于灰家堡背斜核部，矿体产在粘土岩叶灰岩一粘土岩组合之灰岩中，以层状·似层状为主。一些低角度的断层控制了少量的断裂型金矿体。2．金矿床具有低温成矿特征，主成矿期流体包裹体的均一温度2约℃士，出现硅化、白云右化、黄铁矿化和粘土化等围岩蚀变，特征的Au-As-11g-Tl元素组合。矿石中Au主要不均匀分布在富砷环带中。纳米金可能是水银洞金矿床金的主要存在形式，并且快速沉淀在几个微米宽的细小黄铁矿中的砷黄铁矿环带和几一卜微米小的热液毒砂中。成矿条件的骤变和黄铁矿的吸附是重要因素。3．成矿流体具有低温低盐度和较高压力和富挥发份的特点，均一温度在220 ℃士，盐度在6士W七％NoCI、，压力为1．6士0．4Kbal＂s，在Vc，I4＋限川j』包裹体中Cll。含量高达63mole％、N：为18nlole％、C0；为19mole％。高压和富挥发份促使成矿流体从深部迁移至控矿背斜核部，并由于断层的作用挥发份的快速逃逸，压力骤降，促使流体快速卸载，一形成金的快速沉淀，形成微细浸染壮的原生金矿石：4．成矿物质主要来自深部。系卿勺岩矿地球化学研究和同位素示踪显示断，成矿一物质可能是燕山期构造岩浆活动形成的成矿流体（慢源铅）上升溶解地壳铅和混入地壳淋滤错大而形成的壳物质的混合；容矿地层均为正常沉积作用形成，． 没有发现具有特殊意义的沉积层（矿源层）；成矿特征元素Au、As、51。、Tl和伴生的其他热液活动元素来自热液的带入，没有证据显示出地层岩石中有大规模的成矿元素迁出。5．区域＿日也壳的活动性，长时期的热状态，有利于大范围内形成超压成矿流体。而地壳的伸展拉张促使了基底早己有的断裂再度复活，并与成矿期断裂一起切穿地壳，为深部超压成矿流体涌入成矿体系提供了必要的通道和热动力条件，使断裂系统就象抽水泵一样，汇聚成矿流体进入地壳上部成矿体系。由于本地区浅层构造的复杂性，导致成矿现象复杂多样，常形成而状矿化，大区域上呈“金三角”。不象羊国西部地区卡林型金矿产出区，金矿在区域上呈线形分布,众多超大型金矿被发现。

个旧超大型锡多金属矿床地球化学及成因

个旧锡多金属矿床位于云南省东南部，是一个驰名中外的超大型锡多金属矿床。本文在深入细致的野外地质工作基础上，对矿石进行了系统的显微鉴定，并对特征矿物做了电子探针定性、定量及面扫描分析，然后通过微量元素、稀土元素丫同位素地球化学（Pb、S、I－Ie、Ar）对比研究，探讨了矿床的成矿物质来源、成矿流体来源，论证了个旧锡矿区经历了广泛且具有重要成矿意义的中三叠世热水沉积成矿作用和燕山晚期的花岗岩岩浆热液的叠加改造成矿作用。最后重新建立了矿床的成矿模式。论文取得的主要认识如下：1．中三叠世，个旧矿区处于特殊的沉积环境一大陆裂谷系中的局I浪边缘海盆。2．中三叠世安尼期海底喷发的玄武岩，在时间、空间上与区内锡多金属矿床有着密切联系。该玄武岩源于富集成矿元素上地慢区，其地慢源区熔融前经历了交代富集作用。该富集作用对本区超大型锡多金属矿床的形成具有着重要意义。 3．“层间氧化矿”矿体的产状以及矿石类型隐含着同生沉积的信息。 4．矿石显微鉴定结果表明矿区曾发生热水沉积成矿作用，部分接触带矿体是燕山期花岗岩岩浆热液叠加、改造热水沉积矿体形成，在某些层间矿中，尤其是离花岗岩体较近的层间矿，存在后期岩浆热液叠加成矿作用。5．锡在鲡状黄铁矿、胶状结构黄铁矿中的大量存在，表明海底喷流时携带了大量成矿元素，具有成矿的潜力，同时锡石包裹体的存在暗示着海底喷流时可形成锡（SnO，）矿体。6．电气石细脉型锡矿与层间赤褐铁矿型锡矿的矿石及锡石单矿物稀土元素组成与花岗岩稀土对比研究，表明电气石细脉型矿体为花岗岩岩浆期后热液成因，而层间赤褐铁型应为热水沉积成因。层间矿块状硫化物中单矿物的稀土组成分析结果，表明部分层间矿存在热水沉积成矿作用，同时也存在花岗岩岩浆热液成矿作用，这与岩矿鉴定结果一致。层间矿围岩稀土和微量元素结果也表明部分围岩为热水沉积形成。7．矿石铅、硫同位素地球化学特征表明部分铅和硫源于印支期的热水沉积作用，另有部分铅、硫源于燕山期花岗岩岩浆热液作用；氦、氨同位素地球化学资料反映出该矿床早期成矿流体中氦主源于地慢，为热水沉积成因，同时大量放射性成因氦的加入，也表明了有大量后期花岗岩岩浆热液成矿流体的叠加和改造。8．“层间氧化矿”中成分极为单一（赤铁矿、褐铁矿、针铁矿、锡石）的致密土状赤铁矿矿石和部分褐铁矿矿石为热水沉积的直接产物，并非由硫化矿物氧化形成。9．在探讨矿区西区花岗岩的主量元素演化规律的基础上，对东区花岗岩演化规律进行了反演，得出东区花岗岩获得大量的铁，特别是三价铁，表明围岩在花岗岩侵入时就已经存在大量的三价铁，正是在花岗岩的侵入过程中对大量热水沉积的层间氧化矿的改造，导致了花岗岩中三价铁的演化异常。同时根据花岗岩稀土演化规律进行的模拟表明，老厂花岗岩可能“消化”了大量的热水沉积矿化体，其中层间氧化矿占有主要的份额，从而在局部空间形成了强氧化性质的地球化学障。强氧化环境的形成一方面形成老厂花岗岩特别的稀土模式，另一方面加快了含锡热液的分解，促使锡石沉淀并富集成矿。10．重新建立了个旧锡矿的成矿模式：个旧锡矿是长期以来多种地质作用的综合产物，具有多来源，多期次成矿特点，经历了广泛且具有重要的成矿意义的中三叠世热水沉积成矿作用和燕山晚期岩浆热液的叠加改造成矿作用，热水沉积成矿作用形成了以非晶质铁氧化物相为主的层间矿。燕山期大规模的岩浆活动对早期形成的部分层间矿或矿源层进行了叠加改造，个旧锡矿床应属热水沉积一岩浆热液叠加矿床。

Effect of variations in acid properties of HZSM-5 on the coking behavior and reaction stability in butene aromatization

In order to investigate the effect of acid properties on the coke behavior and stability of butene aromatization, we prepared the AHZSM-5 samples with various acid properties by the methods of hydrothernial treatment and K addition. The reaction of butene aromatization was carried out at 350 degrees C and 0.5 MPa in a continuous flow fixed bed. The characterization of the fresh/coked catalysts with NH3-TPD, N-2 adsorption-desorption measurement, and TG techniques has shown that a large amount of acid sites (high acid density) of the AHZMS-5 catalyst can cause a large quantity of coke deposit and serious channel blockage, and so result in a rapid loss of aromatization activity. On the contrary, after a great reduction in strong acid sites of AHZSM-5 catalyst resulting from some K-modification, the presence of only many weak acid sites also could not lessen the formation of coke nor improve the reaction stability of butene aromatization. Interestingly, the simultaneous reduction in the strong and weak acid sites to a desirable level by hydrothermal treating the AHZSM-5 catalyst at a proper temperature can effectively suppress the coke formation and channel blockage, and thus improve its olefin aromatization stability. (c) 2005 Elsevier B.V. All rights reserved.

Dynamic response of a geotechnical rigid model container with absorbing boundaries.

One of the major challenges encountered in earthquake geotechnical physical modelling is to determine the effects induced by the artificial boundaries of the soil container on the dynamic response of the soil deposit. Over the past years, the use of absorbing material for minimising boundaries effects has become an increasing alternative solution, yet little systematic research has been carried out to quantify the dynamic performance of the absorbing material and the amount of energy dissipated by it. This paper aims to examine the effects induced by the absorbing material on the dynamic response of the soil, and estimate the amount of energy reduced by the absorbing boundaries. The absorbent material consisted of panels made of commercially available foams, which were placed on both inner sides of end-walls of the soil container. These walls are perpendicular to the shaking direction. Three types of foam with different mechanical properties were used in this study. The results were obtained from tests carried out using a shaking table and Redhill 110 sand for the soil deposit. It was found that a considerably amount of energy was dissipated, in particular within the frequency range close to the resonance of the soil deposit. This feature suggests that the presence of foams provides a significant influence to the dynamic response of the soil. The energy absorbed by the boundaries was also quantified from integrals of the Power Spectral Density of the accelerations. It was found that the absorbed energy ranged between a minimum of 41% to a maximum of 92% of the input levels, depending mainly on the foam used in the test. The effects provided by the acceleration levels and depth at which the energy was evaluated were practically negligible. Finally, practical guidelines for the selection of the absorbing material are provided.

Tectonics Inversions & Emerald Deposits

In spite of the great amount of emerald deposits throughout the world, the priorities in quality and volume of extracted rough material are the sites of Colombia (Muzo and Chivor emerald belts). This sites are know even before the Spanish conquistadores. Emeralds were extracted from Somondoco mine (today Chivor) since 1537 and from Muzo in 1567. Contrariwise to the majority of the emerald deposits of the world, which are associated with granitic rocks, the Colombian emerald deposits are associated with hydrofracturing (the main factor controlling emerald mineralization) and hydrothermal fluids, rich in beryl, chrome and vanadium, induced by a tectonic inversion of the deep Mesozoic backarc basin, which is also responsible of the majority of the petroleum systems of the foredeep and foldbelt areas (maturation of the source-rocks andcreation of structural traps). The host rocks of the emeralds are carbonaceous calsiltites (calcareous schists) rich in organic matter of Lower Cretaceous age, which are cut by calcite veins, which, often, contain emeralds, particularly when they are folded. Indeed, since long time (Cheilletz, A. and Giulliani, G., 1996) suggested a two-stage model for the formation of the Colombian emeralds : (i) Stage I is characterized by décollement planes (early compressional tectonic regime) within the carbonaceous calsiltites, hydrothermal fluid infiltration and wall-rock metasomatic alteration ; (ii) Stage II (late tectonic regime) deforms the previous veins by thrust-related folds (development of stratiform and hydraulic breccia), which are synchronous of the emerald mineralization. The resulting tectonic structures are complex fold patterns characterized by propagation anticlines with emerald veins and emerald hydraulic breccia in the apexes, as in Quipama, Tendenquema and Chivor mines. Otherwise stated, since all emerald exploitations are, presently underground, exhaustive geological and particularly structural studies are required to reduce the probability of disappointments. The color of emeralds is from light green to thick green with obvious pleochroism. They appears with different colors when observed at different angles, especially with polarized light. The emeralds from Coscuez deposits have a homogeneous intensive color and bluish tone. At Muzo deposit, the emeralds have middle or dark green color with yellowish tone. At the Chivor deposits, the emeralds have less intensive green color with slight bluish tone. The typical inclusions are albite and pyrite, as well as long bubbles with three phase-inclusions according the zones of growth and along the crystal shapes.

OPEN DOORS AND OPEN MINDS: WHAT FACULTY AUTHORS CAN DO TO ENSURE OPEN ACCESS TO THEIR WORK THROUGH THEIR INSTITUTION

The Internet has brought unparalleled opportunities for expanding availability of research by bringing down economic and physical barriers to sharing. The digitally networked environment promises to democratize access, carry knowledge beyond traditional research niches, accelerate discovery, encourage new and interdisciplinary approaches to ever more complex research challenges, and enable new computational research strategies. However, despite these opportunities for increasing access to knowledge, the prices of scholarly journals have risen sharply over the past two decades, often forcing libraries to cancel subscriptions. Today even the wealthiest institutions cannot afford to sustain all of the journals needed by their faculties and students. To take advantage of the opportunities created by the Internet and to further their mission of creating, preserving, and disseminating knowledge, many academic institutions are taking steps to capture the benefits of more open research sharing. Colleges and universities have built digital repositories to preserve and distribute faculty scholarly articles and other research outputs. Many individual authors have taken steps to retain the rights they need, under copyright law, to allow their work to be made freely available on the Internet and in their institutionâ s repository. And, faculties at some institutions have adopted resolutions endorsing more open access to scholarly articles. Most recently, on February 12, 2008, the Faculty of Arts and Sciences (FAS) at Harvard University took a landmark step. The faculty voted to adopt a policy requiring that faculty authors send an electronic copy of their scholarly articles to the universityâ s digital repository and that faculty authors automatically grant copyright permission to the university to archive and to distribute these articles unless a faculty member has waived the policy for a particular article. Essentially, the faculty voted to make open access to the results of their published journal articles the default policy for the Faculty of Arts and Sciences of Harvard University. As of March 2008, a proposal is also under consideration in the University of California system by which faculty authors would commit routinely to grant copyright permission to the university to make copies of the facultyâ s scholarly work openly accessible over the Internet. Inspired by the example set by the Harvard faculty, this White Paper is addressed to the faculty and administrators of academic institutions who support equitable access to scholarly research and knowledge, and who believe that the institution can play an important role as steward of the scholarly literature produced by its faculty. This paper discusses both the motivation and the process for establishing a binding institutional policy that automatically grants a copyright license from each faculty member to permit deposit of his or her peer-reviewed scholarly articles in institutional repositories, from which the works become available for others to read and cite.

Complying with the NIH Public Access Policy - Copyright Considerations and Options

On January 11, 2008, the National Institutes of Health ('NIH') adopted a revised Public Access Policy for peer-reviewed journal articles reporting research supported in whole or in part by NIH funds. Under the revised policy, the grantee shall ensure that a copy of the author's final manuscript, including any revisions made during the peer review process, be electronically submitted to the National Library of Medicine's PubMed Central ('PMC') archive and that the person submitting the manuscript will designate a time not later than 12 months after publication at which NIH may make the full text of the manuscript publicly accessible in PMC. NIH adopted this policy to implement a new statutory requirement under which: The Director of the National Institutes of Health shall require that all investigators funded by the NIH submit or have submitted for them to the National Library of Medicine's PubMed Central an electronic version of their final, peer-reviewed manuscripts upon acceptance for publication to be made publicly available no later than 12 months after the official date of publication: Provided, That the NIH shall implement the public access policy in a manner consistent with copyright law. This White Paper is written primarily for policymaking staff in universities and other institutional recipients of NIH support responsible for ensuring compliance with the Public Access Policy. The January 11, 2008, Public Access Policy imposes two new compliance mandates. First, the grantee must ensure proper manuscript submission. The version of the article to be submitted is the final version over which the author has control, which must include all revisions made after peer review. The statutory command directs that the manuscript be submitted to PMC 'upon acceptance for publication.' That is, the author's final manuscript should be submitted to PMC at the same time that it is sent to the publisher for final formatting and copy editing. Proper submission is a two-stage process. The electronic manuscript must first be submitted through a process that requires input of additional information concerning the article, the author(s), and the nature of NIH support for the research reported. NIH then formats the manuscript into a uniform, XML-based format used for PMC versions of articles. In the second stage of the submission process, NIH sends a notice to the Principal Investigator requesting that the PMC-formatted version be reviewed and approved. Only after such approval has grantee's manuscript submission obligation been satisfied. Second, the grantee also has a distinct obligation to grant NIH copyright permission to make the manuscript publicly accessible through PMC not later than 12 months after the date of publication. This obligation is connected to manuscript submission because the author, or the person submitting the manuscript on the author's behalf, must have the necessary rights under copyright at the time of submission to give NIH the copyright permission it requires. This White Paper explains and analyzes only the scope of the grantee's copyright-related obligations under the revised Public Access Policy and suggests six options for compliance with that aspect of the grantee's obligation. Time is of the essence for NIH grantees. As a practical matter, the grantee should have a compliance process in place no later than April 7, 2008. More specifically, the new Public Access Policy applies to any article accepted for publication on or after April 7, 2008 if the article arose under (1) an NIH Grant or Cooperative Agreement active in Fiscal Year 2008, (2) direct funding from an NIH Contract signed after April 7, 2008, (3) direct funding from the NIH Intramural Program, or (4) from an NIH employee. In addition, effective May 25, 2008, anyone submitting an application, proposal or progress report to the NIH must include the PMC reference number when citing articles arising from their NIH funded research. (This includes applications submitted to the NIH for the May 25, 2008 and subsequent due dates.) Conceptually, the compliance challenge that the Public Access Policy poses for grantees is easily described. The grantee must depend to some extent upon the author(s) to take the necessary actions to ensure that the grantee is in compliance with the Public Access Policy because the electronic manuscripts and the copyrights in those manuscripts are initially under the control of the author(s). As a result, any compliance option will require an explicit understanding between the author(s) and the grantee about how the manuscript and the copyright in the manuscript are managed. It is useful to conceptually keep separate the grantee's manuscript submission obligation from its copyright permission obligation because the compliance personnel concerned with manuscript management may differ from those responsible for overseeing the author's copyright management. With respect to copyright management, the grantee has the following six options: (1) rely on authors to manage copyright but also to request or to require that these authors take responsibility for amending publication agreements that call for transfer of too many rights to enable the author to grant NIH permission to make the manuscript publicly accessible ('the Public Access License'); (2) take a more active role in assisting authors in negotiating the scope of any copyright transfer to a publisher by (a) providing advice to authors concerning their negotiations or (b) by acting as the author's agent in such negotiations; (3) enter into a side agreement with NIH-funded authors that grants a non-exclusive copyright license to the grantee sufficient to grant NIH the Public Access License; (4) enter into a side agreement with NIH-funded authors that grants a non-exclusive copyright license to the grantee sufficient to grant NIH the Public Access License and also grants a license to the grantee to make certain uses of the article, including posting a copy in the grantee's publicly accessible digital archive or repository and authorizing the article to be used in connection with teaching by university faculty; (5) negotiate a more systematic and comprehensive agreement with the biomedical publishers to ensure either that the publisher has a binding obligation to submit the manuscript and to grant NIH permission to make the manuscript publicly accessible or that the author retains sufficient rights to do so; or (6) instruct NIH-funded authors to submit manuscripts only to journals with binding deposit agreements with NIH or to journals whose copyright agreements permit authors to retain sufficient rights to authorize NIH to make manuscripts publicly accessible.

Novel coatings for hard tissue implants

A novel deposition process named CoBlastTM, based on grit blasting technology, has been used to deposit hydroxyapatite (HA) onto titanium (Ti) metal using a dopant/abrasive regime. The various powders (HA powder, apatitic abrasives) and the treated substrates were characterised for chemical composition, coating coverage, crystallinity and topography including surface roughness. The surface roughness of the HA surfaces could be altered using apatitic abrasives of different particle sizes. Compared to the standard plasma spraying process, the CoBlast surface produced excellent coating adhesion, lower dissolution, higher levels of mechanical and chemical stability in stimulated body fluid (SBF). Enhanced viability of osteoblastic cells was also observed on the CoBlast HA surfaces compared to the microblast and untreated Ti as well as the plasma HA coating. CoBlast offers an alternative to the traditional methods of coating HA implants with added versatility. Apatites substituted with antimicrobial metals can also be deposited to add functionality to HA coatings without cytotoxicty. The potential use of these coatings as an infection preventing strategy for application on hard tissue implants was assessed in vitro and also in vivo. Surface physicochemical properties and morphology were determined in addition to surface cytocompatibility assessments using a MG-63 osteoblast cell line. The antibacterial potential of the immobilised metal ion on the surface and the eluted ion to a lesser extent, contributed to the anticolonising behaviour of the surfaces against a standard bacteria strain (S. aureus) as well as a number of clinically relevant strains (MRSA, MSSA and S. epidermis). The results revealed that the surfaces coated with silver substituted apatites (AgA) outperformed the other apatites examined (apatites loaded with Zn, Sr and both Ag and Sr ions). Assessment of bacterial adherence on coated K-wires following subcutaneous implantation in a nude mouse infection model (S. aureus) for two days demonstrated that the 12% wt surface outperformed the 5% wt AgA coating. Lower inflammatory responses were activated with the insertion of the Ag loaded K-wires with a localised infection at the implantation site noted over the two day study period. These results indicated that the AgA coating on the surface of orthopaedic implants demonstrate good biocompatibility whilst inhibiting bacterial adhesion and colonising of the implant surface.

First principles modelling of nucleation and growth during atomic layer deposition onto III-V substrates

Atomic layer deposition (ALD) is now used in semiconductor fabrication lines to deposit nanometre-thin oxide films, and has thus enabled the introduction of high-permittivity dielectrics into the CMOS gate stack. With interest increasing in transistors based on high mobility substrates, such as GaAs, we are investigating the surface treatments that may improve the interface characteristics. We focus on incubation periods of ALD processes on III-V substrates. We have applied first principles Density Functional Theory (DFT) to investigate detailed chemistry of these early stages of growth, specifically substrate and ALD precursor interaction. We have modelled the ‘clean-up’ effect by which organometallic precursors: trimethylaluminium (TMA) or hafnium and titanium amides clean arsenic oxides off the GaAs surface before ALD growth of dielectric commences and similar effect on Si3N4 substrate. Our simulations show that ‘clean-up’ of an oxide film strongly depends on precursor ligand, its affinity to the oxide and the redox character of the oxide. The predominant pathway for a metalloid oxide such as arsenic oxide is reduction, producing volatile molecules or gettering oxygen from less reducible oxides. An alternative pathway is non-redox ligand exchange, which allows non-reducible oxides (e.g. SiO2) to be cleaned-up. First principles study shows also that alkylamides are more susceptible to decomposition rather than migration on the oxide surface. This improved understanding of the chemical principles underlying ‘clean-up’ allows us to rationalize and predict which precursors will perform the reaction. The comparison is made between selection of metal chlorides, methyls and alkylamides precursors.