若干交代成岩成矿作用组份质量转移的计算与分析

本以几种常见的交代成岩成矿作用为例，介绍了一种新的综合性的组份质量转移计算法－真恒量定值非固定同体积质量计算法（TCFM法），并根据计算结果对这些成岩，成岩作用的形成条件进行了分析。     

交代蚀变岩组分迁移量的合理计算--以内蒙古470铀矿床钠长石化粗面岩为例

文章在全面论证已有组分迁移量计算法合理性的基础上,进一步完善了笔者2000年提出的真恒量组分恒定计算法,即:利用岩石的两种实测密度计算交代蚀变岩的实有真迁移质量及其原子数。     

双组份岩石压缩系数推导与试验验证

岩石压缩系数一直是油藏工作者研究的热点问题,近年来黏土矿物的特殊性质对岩石压缩系数的影响已成为人们关注的重点。将岩石视为“骨架+黏土”的双组份模型,从岩石压缩系数定义出发,运用弹性力学理论,推导出双组份岩石压缩系数公式,得到岩石压缩系数与黏土含量及黏土力学性质的理论关系。以大牛地气田含黏土砂岩为对象,通过岩石变内压三轴压缩试验实测岩石压缩系数,并同时进行岩石的微观试验研究。计算出双组份压缩系数公式及其他几种不考虑黏土的传统压缩系数求解方法对应的岩石压缩系理论值,将理论值与岩石压缩系数实测值进行对比分析,结果发现,双组份岩石压缩系数理论值与实测结果更接近,说明了考虑黏土影响的双组份岩石压缩系数理论的合理性,该理论为油气储层岩石压缩系数的预测开拓了新的思路。     

中酸性火山岩中造岩矿物含量的定量计算方法

主要造岩矿物的含量是火山岩分类定名的主要依据。对于基质为微晶质、隐晶质的火山岩，采用常规的薄片显微镜统计矿物含量几乎是不可行的。目前已有的利用岩石化学成分计算矿物含量的方法均不适用于中酸性火山岩。因此，本文基于岩石与矿物之间的化学成分质量平衡原理，提出了计算火山岩实际矿物含量的方法。该方法是利用实际矿物成分，采用最优化方法计算岩石中实际矿物的含量，在很大程度上避免了计算中的人为性。对中酸性火山岩实际样品计算表明，该方法使用简单方便，精度较高。     

岩石矿物细胞元随机性参数赋值方法研究

数值计算中利用随机分布对各单元赋予不同的物理力学参数来考虑岩石的非均质性,赋值过程是纯随机的,并没有考虑岩石矿物组成的结构特征。故提出一种新的岩石非均质参数赋值方法--岩石矿物细胞元随机性参数赋值方法,基于岩石矿物种类及其含量定义细胞元类别判定区间,利用Monte Carlo方法对各个细胞元进行矿物类别判定,并进行相应的参数赋值,通过各矿物细胞元的随机混合体来描述岩石的非均质性。该方法既考虑了组成岩石的矿物种类及其含量（结构特征）,又考虑了组成矿物在岩石中的随机分布特征。针对矿物分布的随机特征,利用两矿物细胞元混合模型和三矿物细胞元混合模型进行数值试验,研究了矿物细胞元随机分布特征对岩石宏观力学参数的影响。研究结果表明,岩石矿物细胞元随机性参数赋值方法具有结构性和随机性的双重特性,其随机性不依赖于随机参数,岩石宏观力学参数受细胞元随机性特征的影响很小。     

X射线粉晶衍射基体清洗法在矿物定量分析中的应用

为了消除层状硅酸盐矿物择优取向对检测结果的影响,本次X射线粉晶衍射定量分析采用基体清洗法,引入刚玉作为清洗剂,用滑石和绿泥石纯样品分别与刚玉以1：1的比例配制成参比样,测试参比样中刚玉、滑石、绿泥石的主衍射峰强度值,根据参比强度公式计算出滑石、绿泥石的参比强度.再把刚玉与定值样（滑石和绿泥石混合样）按1：1的比例配制成待测样,测试待测样中刚玉、滑石、绿泥石的主衍射峰强度值,把所得数据代入基体清洗法计算公式,剔除离散数据,计算出定值样中滑石的含量为81.5%,绿泥石的含量为14.6%;用EVA全谱拟合矿物半定量分析方法测试定值样中滑石的含量为92.9%,绿泥石的含量为5.8%.通过定值样中全岩化学分析铝元素含量换算,定值样中绿泥石的含量应在13%左右,接近基体清洗法的绿泥石矿物定值,与EVA全谱拟合矿物半定量分析方法绿泥石矿物定值相差较大.实验结果表明：利用基体冲洗分析混合物相中层状硅酸盐矿物含量是比较准确的.     

一种计算岩石中矿物组成的新方法

介绍根据显微下观察,应用岩石化学全分析结果和分子量计算法计算岩石中矿物组成的新方法。所得各种矿物的组成是整块岩石在三维立体体积中各种矿物的质量分数,比目前沿用的目测一个岩石切面上各种矿物的面积百分比法更准确,比CIPW标准矿物分子法更符合岩石样品组合的实际情况,而且可用于含云母族、绿泥石族和铀矿物等蚀变矿化的花岗岩及沉积岩、变质岩的矿物组成计算。     

利用岩石化学成分计算花岗岩类实际矿物的新方法

介绍一种在三氏算法(戎嘉树等人于20世纪70年代初提出的一种用岩石化学成分计算花岗岩类实际矿物含量的方法)的基础上经长期实践并不断创新而发展起来的一种新的实际矿物含量的计算方法。该方法针对准铝质花岗岩类、铝过饱和、铝强过饱和花岗岩类分别设计了相应的计算方法,同时也兼顾了碱交代花岗岩及碱长花岗岩,不仅适用于新鲜岩石,也适用于部分蚀变的岩石。该方法在处理岩石化学分析数据的归纳和组合上尽量与实际存在的矿物相结合,力求计算结果与岩石中实际存在的矿物相符。计算过程中提出了长石的修正系数χ,用其修正岩石中钾长石和斜长石的含量,从而确保计算结果与实际相符。计算得到主要造岩矿物(Q、Or、Pl、Bi、Ms、Hb)的含量和反映岩石化学特征的两类参数(Ot、AnPl、K-Na、a、b、Mg)及相关图解。该方法不仅可以计算出岩石中主要造岩矿物的含量,同时还可以反映岩石化学特征、演化过程及其成矿专属性等。     

对A.H.查瓦里茨基岩石化学补充数值特征n值计算方法的讨论

如所周知,在A.H.查瓦里茨基岩石化学计算方法中,n值是主要数值特征A的一个补充数值特征,用来表示岩石中钠原子在组成铝硅酸盐的钾钠原子总数中的百分数。n值不仅能反映出岩石的碱性特点,而且尚可反映岩石中可能出现的含碱矿物,     

岩石宏观流变性质的数值模拟

本文用有限元方法研究多矿物岩石的流变性质,即在一定温度压力范围内单矿物流变性质已知的情况下,采用随机网格划分和材料性质指定的方法,建立三维多矿物岩石的有限元模型,在计算机上计算该岩石模型在不同温度压力下的变形,根据这种数值模拟实验的结果,确定岩石整体的流变性质,而不必再进行真实多矿物岩石的高温高压实验.用有限元方法进行多矿物岩石流变性质的研究可以更为高效和节省,但其前提是多矿物间没有发生化学反应,变形机制仍与单矿物实验时的主导机制一样.本研究中进行了由锗橄榄石和锗尖晶石组成的双矿物岩石的流变实验,鉴于单个的随机生成的模型不一定居有代表性,因此对每一种矿物比例均随机生成了多个岩石模型,进行大量Monte Carlo实验和统计分析.计算结果表明,由两种矿物组成的双矿物岩石整体流变性质介于两者之间且按一定规律分布,与矿物比例有关;但即使同等矿物比例混合后的岩石会由于内部矿物分布结构的不同仍会出现一定差异,特别在试件尺度小时这种效应更为明显,因此多矿物岩石实验试件应该有足够大的尺度.     

广东曲仁两套红层的重矿物组合特征与地层对比

本研究以广东曲仁煤田两套红色地层为对象。工作中各选择了中侏罗统和上白垩统一个完整的地层剖面,进行碎屑重矿物组合、标志特征,重矿物成因和演变,韵律特征和矿物或熟度等研究,初步查明了它们的蚀源母岩类型;揭示了重矿物组合和区域岩石类型变化的原因;指出以重矿物为标志的韵律性和标志层的存在;探讨了矿物成熟度在重矿物研究中的意义;进而提出了划分、对比两套红层的重矿物标志。     

Mass transfer and replacement of minerals in the course of infiltration metasomatism

The direction of Na, K, Ca, Mg, and Fe transfer was determined in the granite-chloride solution system during the metasomatic replacement of granite in response to a temperature and pressure change. The analysis of modeled metasomatic zoning (metasomatic columns) indicates that metasomatic processes of alkaline/acidic and basification/debasification types are controlled by differences in the chemical potentials of components in the solution and rock and by the addition/removal of material due to its excess/deficit in the solution. The former are manifested in the mineralogy of the rear zones of metasomatic columns, while the latter control the total variations in the contents of components in all zones. One of the consequences of this difference is the occurrence of extrema in the distribution of components in zones. Information on the chemical composition of rocks in any given zone does not provide a clue to either the character of the metasomatic processes or the proportions of component concentrations in the solution. In contrast to isobaric-isothermal columns, their thermogradient analogues are characterized by the continuous replacement of minerals and mass transfer in all zones. This predetermines the possibility of the identification of the gradient character of certain columns.     

浙江大桥坞铀矿床深部流体作用的地质-地球化学证据

笔者通过流体包裹体的岩相学、显微测温学以及激光拉曼成分的对比研究,探明了大桥坞铀矿床成矿流体的基本性质（温度、盐度及成分）,结合该矿床的构造和地质-地球化学特征,对成矿流体的来源进行了探讨。研究结果表明,该矿床主成矿期成矿温度为200-250℃,属于中温热液矿床,其成矿流体为富含CO2、H2、CH4等气体组分的中高盐度流体,反映该矿床成矿过程以深部流体作用为主,成矿流体主要为来自地幔的流体。     

The Oslo Rift: P-T relations and lithospheric structure

Extrusion temperatures for basaltic lavas in the Permo-Carboniferous Oslo Rift, estimated from whole rock major element compositions, are estimated to be 1270 to 1340°C. This means that magmatism during the Oslo rifting event was not associated with a large temperature anomaly in the underlying upper mantle. Partial melting is believed to be caused by a combination of crustal extension, a weak temperature anomaly in the underlying asthenosphere, and/or high fluid-contents in the mantle source region (“wet-spot”). Petrological and gcochemical data imply that large masses of cumulate rocks were deposited in the deep crust during the Oslo rifting event. The densities and seismic velocities (V_p) of these cumulate rocks are estimated to be 2.8–3.5 g/cm³ and 7.5–8.0 km/s. A rough estimate suggests that cumulus minerals alone account for a net transfer of at least 2 × 10¹⁷ kg of magmatic material from the mantle into the deep crust. In addition comes material representing

1. (a) cumulate minerals corresponding to eroded magmatic surface and subsurface rocks

2. (b) intercumulus material, and

3. (c) magmas crystallized to completion in the deep crust.

Estimates based exclusively on geophysical data tend to underestimate the true transfer of mass into the lower crust as gabbroic cumulate rocks, and melts crystallizing to completion in the lower crust have densities and seismic velocities similar to those of lower crustal wallrocks.     

Metamorphic veining and mass transfer in a chemically closed system: a case study in Alpine metabauxites (western Vanoise)

In western Vanoise (French Alps), karstic pockets of Triassic‐to‐Jurassic metabauxites embedded in carbonate rocks and containing several generations of metamorphic veins were studied. During blueschist facies metamorphism, a cumulative amount of ～13 vol% of water is inferred to have been produced locally by successive dehydration reactions, and part of this fluid remained in the bauxitic lenses during most of the metamorphic cycle. Field and geochemical evidence show that these rocks have been isolated from large‐scale fluid flow (closed‐system behaviour). It is proposed that the internally derived fluid has promoted the opening of fluid‐filled open spaces (as attested by the euhedral habits of vein minerals) and served as medium for mass transfer from rock to vein. Indeed, the vein infill is obviously the result of chemical interactions, at the millimetre‐to‐centimetre scale, between the rock minerals and the locally produced aqueous fluid. Two vein types can be distinguished based on mineralogical and textural features: (i) some veins are filled with newly formed products of either prograde (chloritoid) or retrograde (chlorite) metamorphic reactions; in this case, fluid‐filled open spaces seem to offer energetically favourable nucleation/growth sites; (ii) the second vein type is infilled with cookeite or pyrophyllite, that were present in the host rock prior to the vein formation. In this closed chemical system, the components for the vein infill minerals have been transferred from rock to vein through the fluid, in a dissolution–transport–precipitation process, possibly stress‐assisted. These different vein generations all contain Al‐rich mineral infills, suggesting that Al was a mobile element (cm scale) during metamorphism. In these HP rocks, fluid flow may have been restricted, and if so mass transfer occurred by diffusion in an almost stagnant fluid. Metamorphic veins can be seen as witnesses of fluid and mass redistribution that partly accommodate the rock deformation (lateral segregation).     

The Crystallization of Intermediate and Acid Magmas at Ben Nevis, Scotland

The Ben Nevis igneous complex consists of a central mass ofrhyodacites surrounded by four plutonic intrusions. In orderof intrusion, these are: the Outer and Inner Quartz Diorites,which are complex rock types with varying chemical and mineralogicalcompositions; the Porphyritic Outer Granite; and the Inner Granite.The plutonic rocks crystallized under comparatively low pressureand thus contain no primary aluminou shornblende, its placebeing taken in all but the most acid rocks by primary pyroxene,which was commonly replaced by an alumina-poor hornblende atlower temperatures. The ferromagnesian minerals in the acidrocks are more magnesian than those in the more basic rocks.This is considered to be due to the partial pressure of oxygenremaining constant at an unusually high level as the magmasconsolidated, causing the minerals to be increasingly enrichedin magnesium as crystallization proceeded.     

苏鲁地体南部南岗-高公岛韧性剪切带的变形记录、组分迁移和体积亏损

南岗-高公岛韧性剪切带是一条自南东向北西斜向逆冲的岩片边界性构造带,糜棱岩化作用强烈。韧性变形过程中,岩石中的主要矿物长石、黑云母等发生了不同程度的分解或蚀变并导致组分迁移。其中,活动组分的迁移是流体渗滤作用引起的,不活动组分的变异是体积亏损造成的。通过对韧性剪切带内不同变形程度岩石主要地球化学组分的对比分析,确立等比线斜率,计算出初糜棱岩的体积亏损率约为17%,糜棱岩的体积亏损率约为27%;质量平衡计算结果及等比线图表明韧性剪切作用导致SiO2流失量最大,其次为Al2O3,FeO、CaO、Na2O等都有不同程度的丢失,表明它们具有较强的活动性,MgO位于等比线上方,属于带入组分。糜棱岩中的石英或长英质条带和团块是长石的钠黝帘石化、绢云母化和黑云母的绿泥石化等导致SiO2、Al2O3、Na2O、CaO、FeO等活动组分从岩石中析出迁移形成的。这种岩石体积亏损和组分迁移是部分难溶组分富集的重要机制,对研究韧性剪切带中长英质条带和部分贵金属矿床的形成机制具有重要的指导作用。     

对内蒙古贺根山蛇绿岩的新认识

本文将华北板块和中亚-蒙古陆块缝合带中前人划分的"贺根山蛇绿岩套"划分为三个不同组分、不同成因的岩系:以含金刚石和其它幔源矿物的变质橄榄岩系为主,包括堆晶杂岩在内的镁铁-超镁铁岩系;含放射虫硅质岩夹层的玄武岩系;上覆的火山-沉积岩系。根据地质学与年代学证据,可以认为蛇绿岩形成于晚泥盆-早石炭世。在此基础上,本文重点讨论了三个问题:(1)结合不同尺度的构造研究,将含金刚石等幔源矿物的超镁铁岩看作源自地幔转换带的幔源熔-流体,在软流圈底辟体上涌的背景下持续上升,在板块对接的过程中构造侵位的岩石。据此,对现有的蛇绿岩概念提出了补充;同时提出贺根山在板块汇聚过程未发生明显的俯冲和碰撞,而是通过拼贴的方式连为一体的;(2)贺根山具有OIB特征的玄武岩与朝克山MORB的对比,表明不同来源的多地块的存在及板块闭合时间的差异均反映了陆间小洋盆的特征;(3)将上覆在玄武岩系之上的火山沉积岩系看作洋盆最后充填的产物,反映了古亚洲洋闭合过程中小洋盆直接从洋壳转化为陆壳的过程,最后从时空角度进一步讨论了小洋盆闭合的特征。