安徽月山地区闪长岩类岩浆动力学及其与成矿作用的联系

基于火成岩石学、流体动力学、流变学及传热学和热力学的研究，计算和分析了安徽月山地区闪长岩类岩浆的分凝、上升、对流、定位和结晶等岩过程的速度与，并探讨了岩浆的某些物理性质和动力学行为如熔体的含水量、水的运动特征，岩浆上升速度和对流状态等与成矿作用的联系。     

河南维摩寺—草庙A型花岗岩岩浆物理性质及定位机理

岩石动力学是一门刚刚兴起的边缘学科。本文是岩浆动力学理论的应用。文中基于岩石化学成分,计算了河南维摩寺—草庙A型花岗岩熔体在不同温度下的粘度和密度,阐述了岩浆上升通道和上侵时的温度,继之依据粘性流体力学理论,通过各种计算探讨了岩浆上升速度,岩浆冷凝速度和钾长石斑晶的沉浮行为及其分布机理,对有关地质问题做出定量化解释。     

岩浆作用的物理过程研究进展

概略地介绍了８０年代以来硅酸盐熔体及硅酸盐晶－液悬浮体的密度、粘度、熔体结构、流全动力学等方面的研究动向,及其对岩浆作用、岩浆运移、岩浆侵位机制的动力学约束条件,硅酸盐熔体的结构是制约熔粘度的主导因素,化学成分对熔体匠控制是通过改变熔体结构而实现的,粘度在一定程度上决定着岩浆的迁移、侵痊和喷发方式。密度和浮力是岩浆上升侵位的重要约束,地壳是岩交涉升的一个密度过滤器岩浆最终由于浮和的消失而停止上升。     

硅酸盐熔体结构与某些地质特征的关系

熔体结构是各种岩浆作用过程的重要表征。本文定性地探讨了熔体结构与某些岩浆物理性质、岩浆动力学特征和地球物理场间的关系，具体涉及的关系方面包括氧逸度、水逸度、ｐＨ、Ｅｈ、过冷度、晶核临界半径、成核速率、晶体生长速率、岩浆运移速度、扩散系数、重力场、地壳厚度、大地构造等。     

新疆诺尔特地区阿提什花岗岩体岩浆演化动力学

新疆诺尔特地区花岗岩分布广泛,其中阿提什花岗岩体与燕山期阿克提什坎金矿床在时间、空间上密切相关,该岩体为二长花岗岩,具铝过饱和特征,属于高钾钙碱性系列.为探讨阿提什花岗岩体与阿克提什坎金矿床成矿的关系,从动力学角度探讨了燕山期阿提什花岗岩体的岩浆演化机理.瑞利数计算结果远远大于104,显示阿提什花岗岩体岩浆中对流作用是存在的.模拟计算显示,分凝作用是存在的,分凝作用对于大颗粒的残余体的分离作用明显,而对于小颗粒的残余体的分离作用很小.晶体分布参数S介于10-7～10-3间,显示岩浆中晶体基本上是自由浮动的,晶体的运动受流体的运动控制.斜长石粒度分布的体视学特征显示,在对流条件下,岩浆成分通过晶体与熔体的差异运动而发生变异.     

火成岩中的超临界流体晶及其研究意义

流行火成岩理论中,岩浆被默认为自然熔体,因而火成岩中的矿物晶体都形成于熔体的结晶作用,可称为熔体晶。许多证据表明,火成岩中也可以含有从超临界流体析出的晶体,被称为超临界流体晶(文中简称为流体晶)。根据三个典型实例分析,流体晶既可以从超临界流体直接析出,类似于从热液析出晶体的过程;也可以由超临界流体浓缩产生的熔体结晶形成。不管是哪一种晶出方式,流体晶产生的前提都是岩浆达到流体过饱和态;而满足这一前提的基本条件则是透岩浆流体过程和岩浆快速上升。结合前人关于熔体流体平衡条件的研究进展,以及熔体黏度对挥发分含量和岩浆上升速度对熔体黏度的依赖,发现透岩浆流体过程与岩浆上升过程之间具有耦合关系,这种关系可以用来阐明岩浆系统行为非线性变化的原因。流体晶的研究具有重要意义,可用于：(1)提供一种研究岩浆系统流体条件的新途径;(2)揭示岩浆系统偏离理想态的程度;(3)为反演岩浆系统动力学过程提供新的约束;(4)为识别致矿侵入体和评估侵入体的找矿潜力提供新的矿物学标志;(5)理解火成岩理论中一些长期得不到解决的问题,如岩浆中挥发分溶解度问题、冻结岩浆的活化问题、岩浆成矿专属性问题。     

广西栗木花岗岩岩浆气—液分异作用与成矿作用

广西栗木花岗岩是华南地区具有代表性的含锡、钨、钽、铌矿的稀有金属花岗岩,发育一些紧密共生但结构有明显差异的岩石。在岩相学研究的基础上,运用热动力学原理对这些特殊地质现象进行成因分析以了解相应的岩浆演化过程,得出的结论构成了岩浆演化的动态证据链并相互印证,且与热动力学方程检验结论相吻合。研究结果表明,气—液分异是稀有金属花岗岩最重要的成岩与成矿作用机制。当富水岩浆上升侵位时,岩浆发生大规模的气—液分异作用,形成新的熔体相和大量夹带气相的气泡。新的熔体相因饱和水压尸(H_2O)的突然降低而过冷却结晶形成斑状结构岩石,气泡则上升迁移至不同部位,随后破裂再次发生气—液分异形成残余气流体和残余熔体相。残余气流体进一步交代先结晶的斑状结构岩石形成蚀变带花岗岩,或者结晶形成伟晶岩。残余气流体还是金属成矿元素迁移的主要载体,岩体内带的蚀变花岗岩型锡铌钽矿的成矿作用主要与残余气流体对花岗岩的自交代作用有关,而岩体顶上带的岩脉型钨锡矿的成矿作用主要与残余气流体在围岩裂隙中的结晶作用有关。     

粤北石人嶂莲花山隐伏花岗岩侵入体岩浆动力学特征分析

基于矿床地质特征的研究,以构造地质学、流体力学等为主要研究手段,对粤北石人嶂矿区含钨矿花岗岩侵入体进行分析。通过对岩体形成时的温压条件、岩浆密度、岩浆粘度、岩浆冷凝速度等岩浆动力学参数进行计算,并分析岩浆动力学特征,发现了密度值随温度的变化规律,对于侵位过程中的能量聚集有利,冷却速度缓慢,因而有足够的时间满足任何晶体生长。通过花岗岩体侵位机制的深入探讨,查明了岩体侵位与钨矿化的关系,为总结矿床的成因提供了流体动力学依据,为矿床成因探讨和矿山可持续开发利用提供了科学依据。     

安徽沙溪含和不含铜（金）矿斑岩斜长石斑晶粒度统计及其岩浆结晶动力…

通过对沙溪矿区含矿与不含矿斑岩中斜长石斑晶的粒度统计，计算出平均矿物粒度（Ｓ）、矿物分布密度（Ｄ）及矿物分布均匀度（Ｈ）；再根据晶体大小分布理论（ＣＳＤ），计算出斜长石的晶体生长速率、成核密度及成核速率等岩浆结晶动力学参数；发现含矿斑岩较无矿斑岩有高的成核密度和成核速率，而晶体生长速率则较低；指出成分相近的斑岩在岩浆结晶动力学特征上的极细差别可能造成岩体含矿性明显不同。     

岩浆补给作用对硅质火山岩浆系统演化的制约

硅质火山喷发作为大陆地壳岩浆活动的重要表现，在研究大陆地壳形成与演化、探讨岩浆过程与动力学机制等方面具有重要的价值，其通常所表现的强烈爆炸式喷发，甚至可以导致全球性的环境和气候变迁。硅质岩浆系统在开放体系中不同来源岩浆的贡献和相互作用是目前研究的热点问题。持续的岩浆补给可以延长岩浆存储的时间，促进岩浆房的对流、岩浆的分异演化以及晶体 熔体的分离和晶粥的再活化，同时也是触发火山喷发的重要机制之一。此外，岩浆补给以及硅质岩浆的晶体 熔体演化过程也是火山喷发产物多样性的原因，导致同一火山在其活动过程中喷发产物规律性的变化，如富晶体火山岩、贫晶体火山岩、火山岩成分分层、以及复活岩穹和中央侵入体等。因此，岩浆补给作用是制约硅质火山岩浆系统演化和火山岩成分多样性的重要因素，也是活动火山监测和灾害评估的重要依据。岩石学、岩石地球化学、矿物(长石、石英、石榴子石、锆石等)同位素及成分变化，以及模拟实验、地震层析成像等研究为揭示硅质岩浆系统中的岩浆补给作用和复杂岩浆过程提供了多种视角。     

花岗岩浆形成定位机制的思考与研究进展

花岗岩(广义)是陆壳的标志,也是地球岩石圈区别于其它行星岩石圈的标志。文章介绍了行星探测和大洋调查等方面的成果对花岗岩形成的地质约束:行星从岩浆表壳向岩石表壳转换过程以及现代地幔过程,均没有产生有规模意义的花岗岩;花岗岩及其所标志的陆壳,应是星球出现水圈和沉积岩之后的产物;花岗岩在地球岩石圈二维空间上的平均生长速率,大约为485×10~3km~2/Myr;岩浆主要来自地壳岩石的部分熔融(深熔)。在此基础上,文章介绍了深熔作用方面的研究进展,讨论了部分熔融岩石的流变行为与其内熔体比的关系,并比较了岩浆侵入模型与岩浆对流模型在解释花岗岩形成定位机制方面的异同。侵入模型的困难之一来自岩体与源区分离。由于源区位于岩体下方且远离岩体,因而是不可观察的,除非岩体及其与源区之间的岩石因风化或构造被剥蚀殆尽。文章最后介绍了"深熔-对流"模型的研究进展。该模型认为"源区"与"定位区间"是统一的,当"源区"岩石的熔体比例超过流变学的临界熔体比,岩石转变为"脏"岩浆;"脏"岩浆层内的重力分异诱发热对流,后者引起"顶蚀作用",导致重熔界面(MI)或固-液转换界面(SLT)不断向上移动和岩浆层的逐渐增厚。基本认识是:熔区内的热对流是深熔作用能够形成大规模花岗岩浆的必要条件;没有对流,陆壳岩石的部分熔融只能产生混合岩,不能产生岩基规模的花岗岩。     

Genesis of mineralized cavities (Miaroles) in granitic pegmatites and granites

Analysis the development of large fluid segregations in a flux of small fluid bubbles during the degassing of granitic (pegmatitic) melts indicates that the velocity of the buoyant ascent of fluid bubbles depends on their sizes, the viscosity and density of the melts, and the duration of melt flow. Possible variants of the primary and secondary boiling of magma are discussed depending on the P-T conditions and concentrations of H₂O, F, B, and other components dissolved in the magma. The possible density ranges of the fluid phases are considered, along with the viscosity and density of granitic (pegmatitic) melts, velocities of the buoyant ascent of fluid bubbles in them, and the processes of their coalescence and accumulation in the temperature range of 650–850°C. Provisional evaluates are obtained for the duration of melt crystallization and the development of intrusive massifs and dikes of granites and syngenetic intragranite and epigenetic (intruded into the host rocks) granite pegmatites. Simulation data and geological observations suggest that large fluid segregations were formed already in the magma chambers in which the heterogeneous granite (pegmatitic) magma was derived, before its emplacement into the host rocks. These generation regions could be magma chamber areas within granite intrusions, in which melts enriched in volatiles were accumulated and then degassed with the release of fluid phases of various composition and density. The crystallization of fluid-rich melts under favorable conditions gives rise to granites with miarolitic structures. The emplacement of heterogeneous pegmatitic magma (which consists of immiscible silicate melts and large fluid segregations) into the host rocks results in that these segregations (would-be miaroles) occur in any part of the pegmatite-hosting chamber. This explains why miaroles of significantly different composition and with broadly varying proportions of their filling minerals may occur in various parts of pegmatite veins or their swells, as well as near contacts with the host rocks.     

富F熔体-溶液体系流体地球化学及其成矿效应--研究现状及存在问题

高度演化花岗岩类多为富F的熔体溶液体系 ,具有鲜明的、不同于其他体系的地球化学行为。富F岩浆固相线和液相线的降低和岩浆寿命的延长 ,使残余熔体与热水热液的性状差异减小 ,模糊了岩浆与热液之间的界线。最近对于富F、B和P伟晶岩中熔融包裹体的研究获得了新的进展。在约 70 0～ 5 0 0℃的温度和 1 0 0 0× 1 0 5Pa的压力下 ,在伟晶岩石英中发现两种不同类型的熔体包裹体 ,一种是富硅酸盐、贫水的熔体包裹体 ,另一种是贫硅酸盐、富水的熔体包裹体。两种熔体在硅酸盐 (+F +B +P) 水体系的溶离线边界上同时被圈闭。这表明 ,在地壳浅部侵位的侵入体 ,当温度≥ 70 0℃时 ,水在富F、B和P的熔体中可以无限混溶 ;而一旦温度降低 ,就会分离为两种共存的熔体并伴随强烈的元素分异作用。在溶离线的富水一侧形成与正常硅酸盐熔体有很大不同的高度富挥发份的熔体 ,这种致密、高粘度、高扩散性以及高活动性的超富水 (hyper aqueousmelt)熔体 ,可以与水溶液流体相类比。这为岩浆热液过渡性流体的假说提供了新的有利的证据。此外 ,在这种具有超富水和熔体特征的过渡性流体中 ,微迹元素可能具有特殊的地球化学行为 ,如在许多晚期花岗岩包括淡色花岗岩和伟晶岩中稀土元素配分模式所显示的四分组效应等。富F熔体溶液体?     

The role of discontinuous magma inputs in felsic magma and ore generation

For a long time, granites have been considered as passive bodies ascending under intrinsic negative density and viscosity contrasts with their host rocks. Chemical variations within a granitic body resulted from in situ differentiation and crystal fractionation. Since the mid 1980s, this global view has been significantly modified by (i) shifting melting from water-saturated conditions to fluid-absent reactions, (ii) increasing the role played by the mantle during granite generation, (iii) reassessing the rheology of partially molten rocks, (iv) demonstrating stepwise segregation and ascent of magmas by analogue and numerical models, (v) combining structural, geophysical and geochemical studies to reveal the internal structures in granitic plutons. It results that a granitic body is built up by a discontinuous accumulation of successive magma intrusions. The discontinuous nature of magma emplacement has also significant consequences for its ability to generate ore. The processes that lead to ore deposits are examined, with a brief review of the magmatic and fluid phases that concentrate ore forming elements. Examples are taken from crustal-derived granites and porphyry-type deposits. Those are considered as the two end-members of magmatic and hydrothermal ore deposits. The source characteristics of the magma, the emplacement mechanisms and magma mixing processes are the frame that controls the potential to carry base metals with the magma. The distribution of elements is controlled by diffusion, partition between minerals and melt, solubility and redox conditions. Variations of those parameters are examined by considering their activation energy which controls the exponential dependence with temperature. A characteristic length depending on the activation energy, temperature variation and time is estimated for a characteristic time lag of 30 ka. The intrusion of a magma into a magma chamber of similar composition, hence temperature, has few effects on diffusion, partition coefficient and redox conditions, because of a too low temperature contrast. The intrusion of a mafic magma into a felsic one induces a variation of 300 °C in both magmas. The characteristic length of diffusion may vary by up to two orders of magnitude, whereas the variation of partition coefficients is only one order of magnitude. The redox conditions are about 2.5 log unit in the mafic magma, but they can vary by 7 log units in the felsic magma. Hence, a strong decrease in δD values is observed in porphyry-type deposits. The effect is a removal of the elements with higher activation energy (W, Sn, Zr) from the mafic to the felsic magma. Deformation during the late stages of emplacement also controls ore formation.     

Geochemical evolution of halogen-enriched granite magmas and mineralizing fluids of the Zinnwald tin-tungsten mining district,Erzgebirge, Germany

We remelted and analyzed crystallized silicate melt inclusions in quartz from a porphyritic albite-zinnwaldite microgranite dike to determine the composition of highly evolved, shallowly intruded, Li- and F-rich granitic magma and to investigate the role of crystal fractionation and aqueous fluid exsolution in causing the extreme extent of magma differentiation. This dike is intimately associated with tin- and tungsten-mineralized granites of Zinnwald, Erzgebirge, Germany. Prior research on Zinnwald granite geochemistry was limited by the effects of strong and pervasive greisenization and alkali-feldspar metasomatism of the rocks. These melt inclusions, however, provide important new constraints on magmatic and mineralizing processes in Zinnwald magmas.The mildly peraluminous granitic melt inclusions are strongly depleted in CAFEMIC constituents (e.g., CaO, FeO, MgO, TiO₂), highly enriched in lithophile trace elements, and highly but variably enriched in F and Cl. The melt inclusions contain up to several thousand ppm Cl and nearly 3 wt% F, on average; several inclusions contain more than 5 wt% F. The melt inclusions are geochemically similar to the corresponding whole-rock sample, except that the former contain much more F and less CaO, FeO, Zr, Nb, Sr, and Ba. The Sr and Ba abundances are very low implying the melt inclusions represent magma that was more evolved than that represented by the bulk rock. Relationships involving melt constituents reflect increasing lithophile-element and halogen abundances in residual melt with progressive magma differentiation. Modeling demonstrates that differentiation was dominated by crystal fractionation involving quartz and feldspar and significant quantities of topaz and F-rich zinnwaldite. The computed abundances of the latter phases greatly exceed their abundances in the rocks, suggesting that the residual melt was separated physically from phenocrysts during magma movement and evolution.Interactions of aqueous fluids with silicate melt were also critical to magma evolution. To better understand the role of halogen-charged, aqueous fluids in magmatic differentiation and in subsequent mineralization and metasomatism of the Zinnwald granites, Cl-partitioning experiments were conducted with a F-enriched silicate melt and aqueous fluids at 2,000 bar (200 MPa). The results of the experimentally determined partition coefficients for Cl and F, the compositions of fluid inclusions in quartz and other phenocrysts, and associated geochemical modeling point to an important role of magmatic-hydrothermal fluids in influencing magma geochemistry and evolution. The exsolution of halogen-charged fluids from the Li- and F-enriched Zinnwald granitic magma modified the Cl, alkali, and F contents of the residual melt, and may have also sequestered Li, Sn, and W from the melt. Many of these fluids contained strongly elevated F concentrations that were equivalent to or greater than their Cl abundances. The exsolution of F-, Cl-, Li-, ± W- and Sn-bearing hydrothermal fluids from Zinnwald granite magmas was important in effecting the greisenizing and alkali-feldspathizing metasomatism of the granites and the concomitant mineralization.Editorial Handling: B. Lehmann     

磷灰石地球化学特征对花岗岩锡成矿能力的指示——以滇西腾冲 梁河锡矿带小龙河锡矿床为例

锡矿床全球空间分布高度不均,成矿与花岗岩密切相关,对花岗岩Sn成矿作用的研究受到学界高度重视。准确示踪岩浆源区和精细刻画岩浆演化过程对理解花岗岩与对Sn成矿之间的关系十分关键。磷灰石作为花岗岩类岩石中常见的副矿物,其化学组成在示踪花岗岩岩浆源区和成岩过程方面有独特优势。本文对滇西腾冲-梁河锡矿带具有代表性的小龙河锡矿床,对矿区内的花岗岩展开磷灰石原位化学成分分析。研究结果表明,小龙河锡矿区的花岗岩为一套高分异花岗岩,显示A型花岗岩特征,主要源于地壳物质熔融,花岗岩形成于相对还原的环境,富F且含有一定量的Cl元素。上述岩石地球化学特征有利于花岗岩浆演化过程中Sn的富集和迁移,说明磷灰石的成分特征可以很好地指示花岗岩浆的成因、演化及其物理化学条件,能有效评价花岗岩的Sn成矿能力。     

熔体包裹体在估算花岗岩类矿床形成压力(深度)方面的应用

在花岗岩类矿床中,花岗岩浆分异出富挥发分熔体/流体的过程,是导致岩浆就位和成矿元素迁移、富集的关键因素之一.在该过程中,同时捕获的不同类别的熔体包裹体和流体包裹体可以互相限定捕获条件,由此可以建立一系列与熔体包裹体有关的地质压力计,进而得到相关分异作用发生的深度.这些深度数值,对于指导花岗岩地区的找矿工作具有重要价值....