岩浆岩综合碱度指数（CAI）的计算方法和意义

根据酸碱电子理论、软硬酸碱理论,可以得到岩浆岩综合碱度指数(CAI)的计算公式,即CAI=0.98×X_(TiO_2)+3.62×X_(Al_2O_3+2.95×X_(Fe_2O_3)+6.54×X_FeO+4.96×X_MnO+7.11×X_MgO+8.32×X_CaO+12.07×X_(Na_2O)+13.05×X_(K_2O),其中X是摩尔分数.CAI值可以更准确地反映岩浆岩的碱性程度,据CAI划分岩浆岩的类型具有许多优点.     

陕西省山阳县小河口地区酸性-中酸性岩体地质特征及其成矿地质条件分析

通过对山阳地区地层、构造、岩浆岩特征的论述 ,归纳总结了区内酸性—中酸性小岩体的空间分布、岩石类型、岩石主要矿物、岩石化学成分、岩石碱度、稀土元素、微量元素等特征 ,从五个方面提出了酸性—中酸性小岩体具有壳幔同熔成因的证据 ,分析总结了山阳小河口地区以酸性—中酸性小岩体成矿作用为主的多金属成矿规律 ,提出了成矿模式。     

基于自然伽马测井的淮南煤田朱集井田煤系岩浆岩生热率研究

为研究淮南煤田煤系岩浆岩生热率特点及其对地温场的影响,以淮南朱集井田为研究对象,基于36个钻孔内6 208个煤系岩石自然伽马（GR）测井值的基础上,利用自然伽马与生热率GR-A的关系式,计算不同岩石生热率及其标准差,结果得出,煤系沉积岩的GR值由大到小依次为泥岩83.83 API、砂岩62.23 API和煤34.32 API,岩浆岩的GR值为103.89 API,远大于沉积岩;岩浆岩的生热率也最大,平均1.63 μW/m3,约为煤的3倍,但因受岩浆岩侵入分期性的影响,其标准差较大。总的来说,朱集井田内煤系岩石放射性生热对区内大地热流的贡献量不大,但岩浆岩的高生热率对岩层生热结构的改变较大。      

统计分析在松辽盆地西部地层母岩类型研究中的应用

综合运用因子分析和聚类分析方法，划分出松辽盆地西部白垩系地层的重矿物组合，结合每种重矿物数据特征求出其概率分布图、P-P正态概率图和P-P自然对数正态概率图，定性辨别每种矿物来源是否单一，用研究区实际地质数据资料，对每段根据重矿物组合判断的母岩类型进行约束和校正。判别英台地区下白垩统的母岩主要是中酸性岩浆岩，其次为中基性岩浆岩以及少量的变质岩。齐齐哈尔地区下白垩统的母岩也是以中酸性岩浆岩为主要母岩类型，但英台沉积体系的中基性岩浆岩含量要比齐齐哈尔相对高一些，齐齐哈尔沉积体系酸性岩浆岩则比英台沉积体系更为发育，且其岩石变质程度深。     

CIPW标准矿物计算方法与程序设计

CIPW标准矿物计算方法是一百多年前由Cross、Iddings、Pirrson和Washington四位学者设计的岩浆岩岩石化学数据的处理方法,至今在岩浆岩研究中仍发挥着重要的作用.国外学者先后开发了多款软件及Excel工作表,但国内在相关的软件开发方面却显得薄弱.本文在全面评估CIPW标准矿物计算方法的基础上,介绍了作者应用Excel VBA设计的一套计算机程序,该程序除了可计算出标准矿物组成以外,还可计算常用的岩石化学参数.经与前人的计算结果对比表明,该程序的计算结果正确的、可靠的.     

甘肃省沃尔给花岗岩体中黑云母的成分对其岩体碱度的响应及成岩成矿意义

矿床的形成与其成矿地质体的成因和岩石化学性质密切相关,因此有必要对岩体碱度与成矿关系进行深入研究。通过甘肃省沃尔给花岗岩体的采样测试,并对国内52个各类矿床中与成矿有关岩体中黑云母的主量元素化学成分进行统计和分析,进行寄主岩石碱度判别。研究结果显示：研究区与Cu、Au成矿有关的岩体位于高碱度区域内,而与Sn矿形成有关的岩体均属于低碱度岩石系列。岩浆熔体早期至岩浆后期热液阶段,氧逸度的变化由高到低,介质的碱度逐渐增强,Cu、Au矿床的形成大致经历上述的成岩成矿过程。岩浆结晶过程早期低氧逸度、高碱度有利于Sn的活化迁移,岩浆期后热液阶段的高氧逸度、低碱度有利于锡石的沉淀,但是由于锡石沉淀过程中不断消耗O2,致使其较高的氧逸度显著降低。认为碱度与氧逸度之间相互作用、相互影响进而引起矿化的发生。     

准噶尔盆地南缘侏罗系碎屑成分特征及其对构造属性、盆山格局的指示意义

砂岩碎屑成分分析是进行沉积物源岩石类型、构造属性和盆山演化分析的重要途径。准噶尔盆地南缘侏罗系物源构造属性以“再旋回造山带”、“弧造山带”和部分“岩浆弧”物源为特征,物源岩石类型主要为中酸性岩浆岩、变质岩和沉积岩,岩石成分、重矿物含量及其组合显示东、西剖面在物源上存在一定差异。天山内部侏罗系物源构造属性以“再旋回造山带”、“混合造山带”为主,物源岩石类型主要为中酸性岩浆岩和变质岩,但各剖面的岩石成分、重矿物组合特征及相对含量差异较大。综合天山内部与准噶尔盆地南缘野外剖面沉积特征、岩屑成分及钻井岩心分析表明,天山地区早、中侏罗世盆山格局以盆地沉积范围大、天山正地形较小为特征,不存在地理分割明显的天山山脉,侏罗纪盆地南缘至少存在三个物源体系(西准噶尔山、克拉麦里山和(古)天山);晚侏罗世一早白垩世早期,岩石成分成熟度偏低,砾岩等粗碎屑沉积明显增多,同时不稳定重矿物及其组合稍有增加可能与晚侏罗世天山构造格局分异、构造活动相对活跃有关,天山山脉明显隆升并造就天山南北沉积环境的巨大差异。     

安徽省岩浆岩放射性生热率特征研究

安徽省位于中国东南部,岩浆活动频繁,燕山期岩浆活动最为发育,岩浆岩出露面积超过13 000 km~2,不同类型、不同成因的岩石均有发育,并以大别山、长江中下游和皖南地区较为集中。本研究在安徽省不同岩浆岩带共采集159块样品开展岩石密度和放射性生热元素含量测试,结合前人对安徽省岩浆岩放射性生热元素的测试结果,首次对安徽省岩浆岩开展了系统的放射性生热元素统计研究。结果表明：安徽省岩浆岩总体上U、Th、K平均含量相差较大,花岗质岩石及中酸性火山岩的U、Th、K含量较高,基性岩浆岩的U、Th、K含量较低;不同类型的岩浆岩放射性生热率相差较大,花岗质岩石和中酸性火山岩生热率相对较高且变化范围较宽,基性岩浆岩生热率较低且变化范围较窄;金寨和长江中下游地区部分花岗岩生热率超过5μW/m~3,为高产热花岗岩;岩浆岩的热贡献主要来自于U和Th的放射性衰变热,K的衰变热贡献相对较低,一般不超过10%。通过本文研究,结合前人对安徽省地质地热等方面的研究成果,发现岩浆岩放射性生热对安徽省温泉分布、干热岩勘探和U矿床勘探等具有重要的意义,可为安徽省后续地热资源勘查开发研究提供支撑。     

与金属矿床有关的中-酸性侵入岩氧-钠、硫-钾成矿专属性法则的探讨

问题的提出关于岩浆岩的成矿专属性问题,前人从岩浆的酸度、碱度、岩浆岩时代、矿物学及地球化学等不同角度进行过许多研究,尤其是岩浆碱度对成矿的控制作用,更受到中外学者的注意.许多人对一些具体矿床或矿化类型研究后,总结了岩浆碱度与某些矿化类型间的关系,得出一些有益的结论.无疑,这些工作为岩浆岩成矿专属性的研究打下了     

多宝山地区岩石反射波谱研究

黑龙江多宝山地区岩石反射波谱研究表明，海西期岩浆岩反射率（ρ）最高，古生代地层次之，火山熔岩最小，岩浆岩中ρ值大则蚀变作用强，ρ值变化大则蚀变类型多，０．７０μｍ谱是岩浆岩蚀变作用显著与否的标志，岩石经热流体后期改造作用后产生强的１．４０、１．９０和２．２０μｍ特征谱。火山熔岩ρ值与ＳｉＯ＿２含量呈正相关，其铜含量高、蚀变作用强则ρ值变化大，ρ值在ＮＩＲ区差异最大并形成三个优选窗口。古生代地层ρ值与碳含量、特征谱数呈负相关，Ｃａ含量、基团与特征谱数、强度呈正相关。据岩石波谱数据及其计算值，文章演绎出地面波谱叠合法并综合其他方法确定了区内ＴＭ图像处理的最佳波段组合。     

Influence of oxygen fugacity on mineral compositions in peralkaline melts: The Katzenbuckel volcano, Southwest Germany

The igneous rocks of the Katzenbuckel, Southwest Germany, represent a unique and unusual alkaline to peralkaline association within the European Volcanic Province. The magmatic activity can be subdivided into two main phases. Phase I comprises the main rock bodies of phonolite and nepheline syenite, which were later intruded by different peralkaline dyke rocks (tinguaites and alkali feldspar syenite dykes) of phase II. The dyke assemblage was accompanied by magnetite and apatite veins and was followed by a late-stage pneumatolytic activity causing autometasomatic alterations.

As is typical for alkaline to peralkaline igneous rocks, early mafic minerals of phase I rocks comprise olivine, augite and Fe–Ti oxides, which are substituted in the course of fractionation by Na-amphibole and Na-pyroxene. For the early magmatic stage, calculated temperatures range between 880 and 780 °C with low silica activities (0.4 to 0.6) but high relative oxygen fugacities between 0.5 and 1.9 log units above the FMQ buffer. Even higher oxygen fugacities (above the HM buffer) are indicated for the autometasomatic alteration, which occurred at temperatures between 585 and 780 °C and resulted in the formation of pseudobrookite and hematite.

The unusually high oxygen fugacities (even during the early magmatic stage) are recorded by the major element compositions of the mafic minerals (forsterite content in olivine between 68 and 78 mol%, up to 6.2 wt.% ZrO₂ and 8.5 wt.% TiO₂ in clinopyroxene), the unusual mineral assemblages (pseudobrookite, freudenbergite) and by the enrichment of Fe³⁺ in the felsic minerals (up to 2.8 wt.% Fe₂O₃ in alkali feldspar and up to 2.6 wt.% Fe₂O₃ in nepheline). These observations point to a metasomatically enriched and highly oxidized lithospheric mantle as a major source for the Katzenbuckel melts.     

火成岩定量矿物分类刍议(续)(附岩石化学分类及岩浆类型的标准矿物图解)

主要由副长石、长石組成的(碱性) 火成岩的四面体空間投影分类图解含副长石及长石和仅含副长石的火成岩称为碱性岩。碱性岩的产出虽少,其分布面积不超过全部火成岩的1％;但由于矿物组分复杂,岩性变化较大,特定的岩石名称竟占全部岩石名词的35％左右。因此,碱性岩的分类及命名问题,从来就是一个麻烦的事情。     

香港花岗岩风化分级化学指标体系与风化壳分带

火成岩的化学风化过程实质上就是碱、碱土金属组分水解淋失与脱硅富铁铝化的地球化学过程。不同风化程度的岩石处于整个化学风化过程的不同阶段,因而具有不同的化学成分和风化度指标。笔者在对香港九龙两个地方5个钻孔共计150件不同深度、不同风化程度的样品化学全分析结果与岩土风化程度宏观判别结果的相互对比、选择和确认的基础上,建立了香港地区花岗岩风化岩土风化程度工程分级的化学指标体系。这一研究成果的提出不仅有利于提高花岗岩风化岩土工程分类的科。学性、可靠性和实用性,而且可以为风化岩土工程特性与风化作用关系研究提供理论依据。     

Alkaline basic intrusives of Elchuru,Prakasam District,Andhra Pradesh,India

The igneous alkaline rocks at Elchuru start from a parent ijolite-melteigite association to basic malignite, melalusitanite and shonkinite followed by nepheline syenites and then biotite lamprophyres (as dykes) at the waning phase of the evolutionary course of the complex. The distinct alkalinity of the rocks is manifested by the development of modal nepheline and calcic amphibole (kaersutite). For both the basic rocks,i.e. alkali gabbro and biotite lamprophyre, the percentages of normative nepheline are always higher than modal nepheline, indicating silica deficiency and alkali enrichment of the mafics. It is evident from detailed petrological and geochemical studies that the two basic members are very much akin to each other and there is no major deviation in their bulk chemistry.     

Rare-earth elements in the rock-forming minerals of melilitic rocks in alkaline-ultrabasic complexes

The rare-earth distributions in melilites and other coexisting minerals of melilite-containing rocks from five alkaline-ultrabasic complexes were analysed by partition paper chromatography and neutron activation. Relatively late differentiates are characterized by elevated relative alkalinity and reduced absolute basicity. The characteristics of melilitic sövites markedly differ from established trends. The minerals studied are richer in LREE than chondrites and REE concentrations in these minerals increase in the late differentiates of the melilitic series. A proportionality between logarithms of La and Sm concentrations in pyroxene and melilite imply that melilite-containing rocks (except melilitic sövite) belong to a similar comagmatic series. The degree of LREE-enrichment in rock-forming minerals directly depends on the alkalinity of the rock. The distribution of REE between coexisting melilite and pyroxene may be used as an additional genetic criterion: p.e. magmatic $\text{La}{}_{\mathrm{Pyx}}\text{La}{}_{\mathrm{Mel}}$ ratio is 0.91, while in metasomatic rocks this ratio is between 1.80 and 1.97.     

赣中周潭群变质沉积岩的微量元素地球化学研究

对赣中周潭群变质沉积岩及其石榴子石等造岩矿物的稀土元素地球化学进行了详细研究.结果表明:造岩矿物只携载了岩石中少部分稀土元素,而大部分稀土元素赋存在副矿物的晶格中;变质过程中稀土元素在石榴子石变斑晶与岩石间达到了分配平衡,石榴子石/岩石间的稀土元素分配明显受体系化学组成所制约;变质岩脉及其矿物的稀土元素组成显示清楚的四重效应,其Zr-Hf,U-Th和Y-Ho等元素对也与变质岩发生了一定程度的分异,它们可作为周潭群在变质过程中流体作用存在的判别标志.     

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。     

论地壳中砷丰度的不均一性与高砷地下水分布的关系

在过去的二十多年以来,世界各地越来越多的地区不断地发现高砷＞50ug/L地下水.饮用高砷水危害到几千万人口的健康,尤其在亚洲.学术界普遍认为区域性高砷水的分布不一定与沉积物源区的岩石的砷含量有关.文章对此观点提出疑问和修正.这主要是基于砷在地壳中的分布与地壳的构造历史有着较明显的空间系统关系.在岩浆岩、沉积岩和变质岩体中,砷的浓度范围为＜1mg/kg到＞100mg/kg.并且砷浓度的分布不为正态,平均值与中值有差异.砷丰度在晶岩中分布的不均一性主要是由于富砷矿物的含量高.目前岩石中砷浓度的数据较少,不足以用于研究砷异常分布,如异常分布图的制定.但是,高砷的硫化物矿物普遍存在于中国的金矿中,而且其分布与板块碰撞的造山带有密切关系.在日本新近的上地壳中,砷(与锡)的丰度均超出地球上地壳的平均值.这里的砷异常已被解释为源于海相沉积物.因此文章提出地壳中的砷高异常与不均一性成因的假说:即海洋-大陆型碰撞之后再加上大陆-大陆型碰撞的不断富集过程.富砷矿物包括硫化物、氧化物及硅酸盐(较少见).这些富砷矿物在风化之后,被下游的快速沉降的盆地积累,使这些地区较易产生高砷地下水.文章指出两个未来研究方向:源区岩石砷的浓度及矿物学研究,和风化作用及沉积过程的研究,以便确证地表中砷的丰度异常与高砷地下水分布的关系.     

Behavior of major and rare-earth elements during the postmagmatic alteration of kimberlites

During serpentinization and subsequent alteration in the absence of brucite, kimberlites accumulate uncompensated silica. Its amount can be calculated from the average compositions of the rock-forming minerals (olivine, calcite, phlogopite) and the chemical compositions of the rocks. The contents of rock-forming oxides and REE were determined in 12 kimberlite pipes of the Yakutian kimberlite province, in 413 samples from secondary-alteration zones and of unaltered kimberlites. Columns of successive kimberlite alterations were constructed for each pipe on the basis of secondary-quartz data; here, the behavior of rock-forming oxides and REE was assessed. All the studied rocks had experienced different degrees of postmagmatic hydrothermal metasomatism at different depths in all the pipes. The changes were reflected in the supply/loss of rock-forming oxides and REE. The supply of REE during the hydrothermal metasomatism enriched the kimberlites with TiO₂, P₂O₅, and CaO. During the removal of REE, most of the rock-forming oxides were partially lost. The maximum REE supply was 67% in the Udachnaya-Vostochnaya pipe and 59% in the Nyurbinskaya pipe as compared with the unaltered kimberlites. The maximum REE loss was 87% in the Aikhal pipe and 81% in the Internatsional’naya pipe as compared with the unaltered kimberlites. The initial REE contents of the postmagmatically altered kimberlites changed considerably in all the studied cases. This conclusion was drawn owing to the use of normative-quartz content as a criterion for secondary alteration.