铁镍触媒合成金刚石内部包裹体的研究

分析铁镍触媒合成金刚石内部的包裹体成分及形成原因. 结果表明: 金刚石晶体中的包裹体主要以FeNi合金和Fe₃C形式存在; 随着生长速度加快, 金刚石内部包裹体的点状分布逐渐增多; 在不同温度下, 进入金刚石晶体内部包裹体的方式不同; 随着包裹体的增多, 合成的金刚石晶体硬度降低. 通过调整合成工艺, 合成了包裹体含量极少、 粒度约为0.6~0.7 mm的金刚石单晶.     

四川大水沟碲矿床成矿物质来源研究

四川大水沟碲矿床是世界首例独立碲矿床。通过对其进行矿床地质、常量与微量元素、矿物包裹体地质及稳定同位素测试分析研究 ,认为该矿床成矿物质具有多源性 ,且不同矿化期的成矿元素、成矿流体来源亦不相同 :主成矿期 Te主要源于地幔岩浆脱气 ,少量来源于基性岩或大理岩 ,S可能主要源于早期形成的磁黄铁矿 ,Bi可能与中酸性、基性岩浆有关 ;成矿流体主要为岩浆气液。     

利用包裹体评价石英脉的含金性

以湘西金矿外围(东部)脉石英为例,研究了包裹体的气、液相成分特点,提出包裹体中的CO_2,HCO_3~-,CO_2/H_2O,HCO_3/Cl~-离子总浓度(ΣI)可作为评价石英脉含金性的标志,并总结出石英脉含金性评价的矿物学特性,预测了外围四个工作小区的成矿远景。     

Fe-Ni-C粉末触媒体系金刚石的合成与表征

利用FeNi粉末触媒在六面顶压机上进行工业金刚石单晶的合成与表征. 结果表明: 在Fe-Ni-C体系合成了优质的六面体、 六-八面体及八面体金刚石单晶; 金刚石{111}晶面的生长属于二维层状生长机制; 金刚石中的包裹体主要由FeNi合金组成.     

木梓园钨钼矿床流体包裹体研究及在成矿阶段划分中的应用

通过对江西木梓园钨钼矿床中流体包裹体的研究。认为该矿床是在高一中温、中低盐度、碱性成矿溶液、弱还原条件下形成的。矿质主要来源于岩浆热液。成矿具脉动特征,可分为4个成矿阶段。     

德兴斑岩铜矿成矿流体演化与来源的流体包裹体研究

主要研究了德兴斑岩铜矿床不同期次脉石英及花岗闪长斑岩石英斑晶中流体包覆体的特征，测定了流体包裹体的均一温度和冰点，估算了成矿流体的盐度、密度等参数．结合花岗闪长斑岩与石英脉中石英氢氧同位素数据的讨论分析，对流体的演化过程和来源进行了探讨．研究表明花岗闪长斑岩石英斑晶中的包裹体代表了岩浆流体的特征，石英脉中的包裹体记录了岩浆流体演化成成矿流体的特征。研究证实成矿流体主要由岩浆流体而来，成矿流体演化晚期有大气降水的加入。     

粤北内洞钨钼多金属矿床流体包裹体地球化学特征

含矿石英脉中的石英发育气液两相原生流体包裹体,成矿流体属低盐度盐水溶液,成矿期石英流体包裹体的均一温度指示:该区钨钼多金属成矿作用主要发生在高中温阶段。并估算得出流体包裹体所代表的主要成矿压力范围为36.35~102.58 MPa,成矿的相应深度范围为2.69~8.37Km,属于典型的中浅成成矿环境。成矿流体为Na2SO4-NaCl-H2O体系。     

甘肃干沙鄂博稀土矿床成矿介质演化过程:来自包裹体的信息

在矿床地质研究基础上,通过对石英、萤石、方解石中流体包裹体岩相学、显微测温分析,对甘肃省干沙鄂博稀土矿床成矿流体的特征、演化及成矿机理进行了讨论.结果表明:矿床中发育大量包裹体,按室温下的成分相态特征,将其分为熔体包裹体、流体-熔体包裹体、气液H2O包裹体、气液CO2包裹体、CO2-H2O包裹体和含子矿物的气液H2O包裹体、含子矿物的CO2-H2O包裹体等7种类型.在成矿过程中,包裹体组合从熔体包裹体→流体-熔体包裹体+流体包裹体→流体包裹体的变化,反映了成矿介质经历了从岩浆→岩浆+热液→热液的演化过程.在岩浆-热液成矿期,流体-熔体包裹体大量存在,以及富H2O相CO2-H2O包裹体与富cO2相CO2-H2O包裹体密切共生,表明成矿时曾经发生两次不混溶作用,早期岩浆-热液不混溶作用导致萤石和REE-氟碳酸盐的晶出,而CO2-H2O不混溶作用引起了硫化物的沉淀.     

江西省德兴市渔塘金矿的流体包裹体研究

渔塘金矿位于扬子地块和华夏地块之间的新元古代江南造山带,属于德兴大型铜金矿集区.渔塘金矿成矿阶段石英脉中的流体包裹体可分为三类:H_2O-CO_2包裹体(Ⅰ型)、富CO_2包裹体(Ⅱ型)和水溶液包裹体(Ⅲ型).成矿前石英-黄铁矿脉主要含有Ⅰ型包裹体,CO_2含量较为一致,均一温度为345℃~383℃,盐度为2.0wt.%~6.5wt.%NaCl eq..在金成矿期脉体中,有三种类型的包裹体,并且气相比和CO_2含量变化较大,Ⅱ型包裹体的均一温度为275℃~314℃,盐度为1.8wt.%~4.8wt.%NaCl eq.;Ⅲ型包裹体的均一温度为278℃~354℃,盐度为4.2wt.%~9.6wt.%NaCl eq.;Ⅰ型包裹体的均一温度为290℃~363℃,盐度为1.0wt.%~5.5wt.%NaCl eq..成矿后石英-黄铁矿脉只包含Ⅲ型包裹体,以较低的温度和盐度为特征.因此成矿前为高温、富CO_2的富矿流体;在成矿期发生了不混溶作用,形成不同盐度的两种流体,导致流体具有较为一致的温度和不同的盐度,金主要在此阶段富集;成矿后流体具低温和贫CO_2的特征.渔塘金矿的成矿流体具有典型的不混溶特征,是典型的造山型金矿.     

马来西亚吉兰丹州安曼金矿床流体包裹体研究

基于安曼金矿床地处马来西亚半岛吉兰丹州西南部,矿体呈脉状赋存于二叠—三叠系浅变质火山—沉积岩系内,并受断裂控制。对安曼金矿床流体包裹和群体成分进行研究。研究研究表明:安曼金矿床各成矿阶段金矿石中主要发育CO2-H2O包裹体及气液两相H2O包裹体,早期阶段主要以CO2-H2O包裹体为主,主成矿阶段CO2-H2O包裹体及气液两相H2O包裹体均有发育,后期多为气液两相H2O包裹体。成矿流体的均一温度、盐度在早阶段分别为248~352℃和1.6%~8.8%,主成矿阶段分别为185~336℃和0.43%~11.6%,晚阶段分别为118~226℃和2.9%~5.1%;包裹体气相成分以H2O和CO2为主,并含有少量CH4和H2;包裹体液相成分中阳离子以Na+,K+和Ca2+为主,阴离子以Cl-,SO42-和F-为主。据沸腾包裹体群的均一温度推测主成矿阶段成矿温度为230~326℃。安曼金矿床成矿流体总体表现为低盐度、富CO2的中低温流体,主成矿阶段流体不混溶作用引起成矿流体中的CO2相分离是促使金沉淀的直接因素。安曼金矿床形成与二叠—三叠纪时期马来半岛中缅马苏陆块和印支陆块间的碰撞造山机制有关,属于造山型金矿床。     

Mineralogical evidence for continental deep subduction

Diamond is an index mineral to prove ultrahigh pressure (UHP) metamorphic conditions because it is only stable at the pressures above 3.3 GPa. Its occurrence in eclogite-facies metamorphic rocks suggests plate subduction to depths over 120 km assuming the normal gradient of lithostatic pressure. Because UHP eclogites are the metamorphic products of basaltic rocks, the occurrence of diamond in the eclogites demonstrates a complete geodynamic cycle in that mafic crustal rocks were subducted t…     

山东省微山稀土矿正长岩类锆石U-Pb年代学 及地球化学特征研究

为了加深对微山稀土矿碱性杂岩体岩浆活动期次及与成矿关系的理解,对微山稀土矿床碱性杂岩体进行岩相学、地球化学分析和锆石U-Pb年代学测定。结果表明,微山稀土矿碱性杂岩体正长岩类地球化学特征相似,具有同源性,为偏铝质碱性岩。稀土总量高,轻重稀土元素分馏明显,呈轻稀土高度富集模式。微量元素组成具有幔源岩浆岩的特征,富集Rb,Ba,Sr等大离子亲石元素,亏损Nb,Ta,Zr等高场强元素,Eu异常不显著。利用LA-ICP-MS U-Pb年代学方法,测得含矿石英正长岩、霓辉石英正长岩锆石U-Pb年龄分别为122.4±2.0 Ma(MSWD=5.2)和130.1±1.4 Ma(MSWD=9),存在2536±6.1 Ma(MSWD=1.6)的继承锆石,表明地壳物质参与成岩过程。结合鲁西燕山期构造演化过程,认为微山正长岩类形成于华北克拉通中生代构造体制转折后的伸展背景下,成矿作用与碱性杂岩体的演化有关。     

华北板块北缘中——-西段早白垩世钾玄岩地球化学特征及对比研究

对内蒙古阿拉善盟苏宏图地区一套早白垩世富钾碱性玄武岩中主量元素和微量元素进行测试, 结果表明: 岩石以富碱(K₂O+Na₂O含量为5.20%~8.92%)、高K₂O/Na₂O比值(0.59~1.03)和高TiO₂ (1.59%~2.05%, 平均1.82%)为主要特征, 为钾玄岩系列。该火山岩富集大离子亲石元素、轻稀土元素及高场强元素, 有微弱的Eu异常(δEu=0.88~1.11)。岩石地球化学特征表明, 华北板块北缘西段的苏宏图组火山岩与中段四子王旗地区及白云鄂博南部的早白垩世火山岩有较大的相似性。苏宏图组火山岩、四子王旗钾玄岩以及白云鄂博南部玄武岩均为钾玄岩系列, 三地火山岩在喷出过程中都较少经历地壳混染作用, Nb和Ta的负异常更可能是古亚洲洋俯冲物质影响的结果。同位素和微量元素分析结果表明, 苏宏图组火山岩与四子王旗钾玄岩源区为被古亚洲洋俯冲板块交代的EMⅠ型富集软流圈地幔, 白云鄂博南部玄武岩富集程度稍弱于其他两地, 但三地源区有相似的演化历史, 都经历了亏损的软流圈地幔交代富集过程。三地火山岩相似的源区演化历史表明, 华北板块北缘中?西段在早白垩世可能有相似的构造运动, 在古亚洲洋闭合后, 晚三叠世南北向挤压缩短, 地壳强烈加厚, 而后下部岩石圈拆沉, 已俯冲的古亚洲洋板块的物质重熔, 对亏损的软流圈地幔进行交代富集, 最终富集的软流圈地幔上涌, 形成沿华北板块北缘中?西段东西向呈线状分布的早白垩世钾玄岩。     

诺敏火山群钾质火山岩特征与成因

为了进一步研究诺敏火山群钾质火山岩的特征及其形成的古构造环境,对该区钾质火山岩样品,做了硅酸盐、同位素与微量元素分析。数据分析结果表明,诺敏火山群钾质火山岩主要岩性为橄榄玄武岩、白榴玄武岩、玄武质浮岩。钾质火山岩是由于地幔物质上涌,底侵于陆壳的底部,造成下地壳少量物质与地幔物质发生混溶作用,以及钾质交代作用而形成的,是大陆板块内部裂谷期岩石圈伸展作用的产物。该套火山岩成因与许多重要的浅成低温热液金矿床及斑岩型铜（金）矿床具有密切联系。该研究对恢复古构造环境,了解地幔组成具有重要意义。     

大兴安岭北段漠河地区塔木兰沟组火山岩地球化学特征

 大兴安岭北段漠河地区分布有大面积的晚中生代火山岩,塔木兰沟组是其中喷发较早的一期。塔木兰沟组是一套中基性火山岩,包括熔岩和火山碎屑岩,研究其成因对于理解大兴安岭北段的构造演化具有重要意义。对塔木兰沟组火山岩样品进行了系统的主量元素和微量元素地球化学分析。结果表明：样品大部分呈碱性,SiO₂的质量分数为52.7%～57.8%,为中基性岩石,岩石类型为玄武质粗面安山岩和粗面安山岩;相容的过渡族金属元素如Cr、Co、Ni等含量低,微量元素比值如Nb/La、Ba/Nb、Nb/U、Ce/Pb等及稀土元素总量的变化范围大,具有右倾的轻稀土元素富集的稀土元素分布模式。岩石成因分析表明,富集的大陆岩石圈地幔先经历了部分熔融,然后熔浆受到了轻度的地壳物质的混染以及一定程度的分离结晶作用,最终形成了塔木兰沟组火山岩。     

25 years of continental deep subduction

This year marks the 25th anniversary of the discovery of coesite in metamorphic rocks of supracrustal origin. This initiated a revolution of the plate tectonics theory due to intensive studies of ultrahigh pressure metamorphism and continental deep subduction. The occurrence of coesite was first reported in 1984 by two French scientists, C. Chopin and D.C. Smith,     

山西临县紫金山碱性杂岩体的地球化学特征

通过对山西临县紫金山碱性杂岩体各类岩浆岩的岩石化学和稀土元素地球化学研究，认为在碱性岩形成过程中，源区岩浆经历了相对偏酸性向相对偏基性再向相对偏酸性的演化过程，K2O，Al2O3含量（质量分数）与SiO2含量（质量分数）呈正相关，TFe2O3，MgO,CaO与SiO2呈负相关关系。不同时期所形成的岩浆岩具有来自上地幔的同源性。     

The possible contribution of a mantle-derived fluid to the Ningwu porphyry iron deposits-Evidence from carbon and strontium isotopes of apatites

Apatite is a characteristic mineral for the iron deposits in the Ningwu region. Apatite shows a range of δ^13CPDB values from -9.6‰ to -0.6‰, and most of them with the δ^13CPDB values distributed in a range of mantle carbon （i.e., -2‰to -9‰）, except for samples T-06-1 and J-06-3. Apatites in the Ningwu porphyry iron deposits yield a narrow variation range of ^87Sr/^86Sr values from 0.706326 to 0.707577, similar to those of the volcanic and subvolcanic rocks and higher than that of a typical mantle-derived magmatic apatite （i.e., about 0.7040）, indicating that formation of the apatites was involved with crust material contamination.δ^13CPDBand ^87Sr/^86Sr values of the apatite indicate a possible contribution of mantle-derived fluid and material to formation of the Ningwu porphyry iron deposits, supported by regional geology, regional gravities and geochemistry of the volcanic and subvolcanic rocks in the Ningwu region.     

A diffusion mechanism for core-mantle interaction

Understanding the geochemical behaviour of the siderophile elements--those tending to form alloys with iron in natural environments--is important in the search for a deep-mantle chemical 'fingerprint' in upper mantle rocks, and also in the evaluation of models of large-scale differentiation of the Earth and terrestrial planets. These elements are highly concentrated in the core relative to the silicate mantle, but their concentrations in upper mantle rocks are higher than predicted by most core-formation models. It has been suggested that mixing of outer-core material back into the mantle following core formation may be responsible for the siderophile element ratios observed in upper mantle rocks. Such re-mixing has been attributed to an unspecified metal-silicate interaction in the reactive D' layer just above the core-mantle boundary. The siderophile elements are excellent candidates as indicators of an outer-core contribution to the mantle, but the nature and existence of possible core-mantle interactions is controversial. In light of the recent findings that grain-boundary diffusion of oxygen through a dry intergranular medium may be effective over geologically significant length scales and that grain boundaries can be primary storage sites for incompatible lithophile elements, the question arises as to whether siderophile elements might exhibit similar (or greater) grain-boundary mobility. Here we report experimental results from a study of grain-boundary diffusion of siderophile elements through polycrystalline MgO that were obtained by quantifying the extent of alloy formation between initially pure metals separated by approximately 1 mm of polycrystalline MgO. Grain-boundary diffusion resulted in significant alloying of sink and source particles, enabling calculation of grain-boundary fluxes. Our computed diffusivities were high enough to allow transport of a number of siderophile elements over geologically significant length scales (tens of kilometres) over the age of the Earth. This finding establishes grain-boundary diffusion as a potential fast pathway for chemical communication between the core and mantle.     

Characteristics and geological significance of olivine xenocrysts in Cenozoic volcanic rocks from western Qinling

Cenozoic volcanic rocks from the Haoti, Dangchang County of the western Qinling Mountains, contain a few clearly-zoned olivines. These olivines are relatively big in grain sizes and usually have cracks or broken features. Their cores have similar compositions (Mg#=90.4-91.0) to those for the peridotitic xenoliths entrained in host volcanic rocks and their rims are close to the compositions of olivine phenocrysts (Mg#=85.5-81.9). The CaO contents in these zoned olivines are lower than 0.1%. These features demonstrate that the clearly-zoned olivines are xenocrysts and disaggregated from mantle peridotites. The zoned texture was the result of the interaction between the olivine and host magma. Available data show that the volcanic rocks would have been derived from the mantle source metasomatized by subducted hydrathermally-altered oceanic crust. The formation of these Cenozoic volcanic rocks was perhaps related to the rapid uplift of the Tibetan Plateau.