岩石压电性

本文介绍了岩石压电性的基本原理。在室内对几个典型的石英脉型矿床的岩石压电性进行了定性及定量的研究。通过实验证实了含石英岩石的压电性及压电效应的基本特征,计算了几个矿区岩石的压电模数。工作实践表明,研究岩石压电性,对寻找石英脉型矿床,以及建立新的地球物理方法均有重要意义,同时也有助于研究石英脉生成世代和定性评价石英脉含矿性等问题。     

南水北调西线工程岩石中石英含量变化及其对TBM施工的影响

石英是各类岩石中广泛存在的一种矿物成分,石英颗粒的大小和含量不仅决定了岩石的强度、硬度和耐磨性,而且直接影响TBM施工的掘进效率。在南水北调西线工程区采集124块岩石样品进行了岩石薄片鉴定,在岩石碎屑粒度分析的基础上,得到了不同采样区域岩石中的石英含量分布特征。基于TBM施工特点,根据不同岩石中的石英含量统计结果,分析了石英含量分布规律对南水北调西线工程TBM施工围岩分类和掘进效率的影响。研究结果表明:(1)砂岩(含杂砂岩)、粉砂岩和板岩中的石英含量具有较明显的差异,砂岩(含杂砂岩)、粉砂岩的石英含量较高,其平均值分别为74.21%和80.41%; 板岩中的石英含量较低,平均值为9.36%。(2)砂岩(含杂砂岩)及粉砂岩中的石英含量一般大于60%,对TBM施工围岩分类的影响属于严重等级; 板岩中的石英含量一般小于30%,对TBM施工围岩分类的影响属于轻微-明显等级。(3)岩石中的石英含量越高,岩石硬度和耐磨性越高,刀具损耗越大,TBM施工掘进速度PR和施工速度AR越低。研究成果可为南水北调西线工程TBM优化选型、施工围岩分类以及施工进度预测提供参考依据。     

用人造压电石英制作高频谐振器

以优质人造压电石英取代天然优质压电石英用于制作高精度、高频、超高频谐振器的研究,在国内外均极重视,是一项很有意义的工作。我所近年来生产的人造压电石英已大量提供生产部门制作中、低额谐振器,稳定地取代了天然压电石英。1969年和1911年我们     

安徽某地蓝晶石单矿物分离及人工重砂定量分析方法

一、岩石的物质组份及主要矿物特征蓝晶石产于蓝晶石岩、蓝儡石白云母石英片岩及含蓝晶石白云母石英片岩三个类型的岩石中。其中蓝晶石岩含蓝晶石50—90%,次要矿物为绢云母、褐铁矿、刚玉、金红石、榍石等。蓝晶石白云母石英片岩含蓝晶石10—30%,主要矿物为石英、白云母,少量矿物有赤铁矿、金红石、黄铁矿等,蓝晶石与白云母呈反消长关系。含蓝晶石白云母石英片岩中,蓝晶     

纵波波速在石英和含石英岩石中的高温、高压效应

纵波波速能在温度高达800℃的石英和含石英的岩石(石英岩,花岗岩),水以及 300MPa的“干”的压力下测得。达到α-β石英转变的温度,石英和含有石英的岩石显示了Vp的特殊性能,测量还显示出Vp极小值点的温度对于单晶体和岩石是不同的。从而表明,在流体静应力下的多晶     

谈谈金矿物探方法及发展前景

在寻找金矿中,物探方法的主要任务是:查明探矿的断裂带、破碎带和蚀变带;圈定含矿岩体和岩层;确定弱矿化带;寻找石英脉和其它含矿岩脉。重力、磁法、激电法、甚低频电磁法等常规方法均有良好效果。试验工作表明,压电法、射电法及较电激电法是很有前途的方法;研究岩石矿物的热电性和热致光特征是值得重视的,对于矿产预测及评价含金矿性都有积极作用。     

陕西宁陕县太山庙金矿地质特征及成因

太山庙金矿位于栗扎坪—七里峡区域性大断裂(F1)的南盘,该断裂旁侧次级平行的构造提供了很好的成矿空间,矿区的岩浆侵入为成矿提供良好的成矿热液,近矿围岩为下志留统大贵坪组第二段,含矿岩石为石英脉,成因类型为岩浆热液型矿床,工业类型为石英脉型金矿。     

金矿物探新方法与新技术简介

1)压电法:该方法是地震法与电法相结合的一种找矿方法。自然界中,某些岩石和矿物具有不同的压电效应,压电法正是以其压电效应的差异为基础进行找矿的。该方法主要用于寻找和查明具有明显压电性差异的伟晶岩型、含金石英脉型矿床。前苏联对该方法研究和     

石英研究进展

石英是自然界三大类岩石(岩浆岩、沉积岩和变质岩)和地壳中广泛分布的一种矿物,由于其具广泛分布性和化学稳定性,可以用于示踪地质历史并解释地质过程,因此近些年来引起了地质学家和矿物学家们的关注。本文结合实际科研就沉积岩、变质岩、岩浆岩以及一些热液矿床中石英的微量元素分布情况、石英在CL探测器耦合扫描电子显微镜(SEM-CL)和光学显微镜(OM-CL)下的颜色、发光强度及构造形貌特征等进行了探讨,并对石英中微量元素与CL颜色、发光强度及构造之间的关系进行了阐述,以此来提供研究石英的一个基础,最后简单论述了如何应用石英的CL特征来示踪或鉴定不同成因的含石英的岩石。     

西藏冲江铜矿含矿岩体与非含矿岩体区分探讨

冲江铜矿位于世界三大斑岩成矿域的特提斯-喜马拉雅成矿域,其大地构造位置属冈底斯-念青唐古拉构造带的冈底斯陆缘火山-岩浆弧中部。矿区含矿岩体与非含矿岩体的岩性相同,很难通过肉眼或常规分析方法把它们区分开来。热释光测试结果表明,矿区岩石的热释光曲线有单峰和双峰两种,矿化主要发生在具单峰的似斑状二长花岗岩中。岩石矿化程度越强,热释光总积分强度值越小。另外,高岭土化对岩石天然热释光有叠加作用,具高岭土化的岩石明显具有更高的热释光值,且高岭土化与矿化成负相关。因此,热释光值可作为判断矿化的一个岩石标型。石英粒度统计也表明,含矿岩体的石英粒度曲线呈韵律式变化,而不含矿的岩石粒度曲线呈渐进式变化。故岩石中的石英粒度也可作为矿化的一个矿物标型。     

Stratabound lead-zinc pyrite ore deposits in upper precambrian carbonate rocks,Rodna Mountains,Romania

The Blazna-Guset mining area is located in the Rodna Mountains, Eastern Carpathians, North Romania. It is mostly covered by the metamorphic rocks of the Rebra Series (Upper Precambrian; K/Ar dating gave 800 m.y.). The middle part of this series — called the Carbonate Formation — contains lead-zinc pyrite ores hosted by prevailingly carbonate rocks. The ores form flat and thin lenses occurring together with fine intercalations of silicate-, graphite- and quartz-bearing rocks within the calcite-dominated limestones. Pyrite, ironpoor sphalerite and galena are the main ore minerals. Chalcopyrite, pyrrhotite and magnetite also occur in small amounts. Within the highly deformed and partly recrystallized parts of the ore bodies bournonite, arsenopyrite and pearceitepolybasite were locally encountered. Ba, Ti and Mn are the most significant ore-accompanying elements.     

Estimating quartz fabrics from piezoelectric measurements

An aggregate of piezoelectric minerals may itself be piezoelectric if the minerals are suitably aligned. Thus quartz-bearing rocks may be piezoelectric, since quartz is one such mineral. It has been shown that some rocks do possess this effect, termed a piezoelectric fabric (Bishop, 1981). The type of piezoelectric fabric may be determined by matching experimental data to theoretical models of piezoelectric fabrics. These theoretical models of pure quartz aggregates are derived by considering the symmetry of the preferred crystallographic directions of the aggregate grains. From the symmetry, the piezoelectric matrix of the model may be determined. The best-fitting model and the orientation of its fabric is obtained by equating the experimental data to each model in turn. For each model, the best fitting fabric orientation is determined by using an inversion routine. If the experimental data are due to a piezoelectric fabric and not to some random or nonpolar distribution of grains, the fabric type (c-axis point maximum or large-circle girdle) and its orientation with respect to the specimen may be determined. The positions and polarities of the quartz a-axes are also specified. A statistical examination of results from a quartz-mylonite shows that the problem of piezoelectric model fitting is well posed, in that the Eulerian angles that specify the fabric orientation are fairly independent important parameters and a sufficiently close fit of the model to the data can be obtained to determine the fabric.     

Mode of occurrence and significance of jadeite in the Kamuikotan metamorphic rocks, Hokkaido, Japan

Abstract In the Kamuikotan zone, jadeite occurs in pelitic rocks, in metaplagiogranites, in veins in amphibolites and mafic sedimentary rocks, and in jadeite-albite rocks. In the first and second types, jadeite is associated with quartz, and is often in direct contact with it. However, such rock-types never occur as part of the coherent metamorphic sequence, but are found only as exotic blocks enclosed in serpentinite. Thus, jadeite + quartz-bearing assemblages are not regarded as representative of the Kamuikotan metamorphism. Lawsonite and aragonite, however, commonly do occur in the Kamuikotan metamorphic rocks, and this metamorphism belongs to a subfacies of the lawsonite-albite facies, in which aragonite is stable. The serpentinite matrix which carried jadeite + quartz-bearing pelites and metaplagiogranites into the metamorphic sequence is interpreted as a tectonic rather than a sedimentary melange.     

关于石英的阴极发光特征及其在砂岩研究中的应用

阴极发光现象,远在一百年前即由Crooks(1879)描述过。1968年,Sippel曾首次用阴极发光法成功地研究了砂岩.区分了碎屑石英与自生石英。1970年,他与Spencel将此种方法用于研究阿波罗11号太空船从月球采回的结晶岩和角砾岩。十年后,德国的Ul Zinkernagel因研究古生代石英砂岩遇到困难,遂援用Sippel的方法,得以详细地区分砂岩中不同来源的碎属石英颗粒,获得了较好的成果。有关阴极发光的原理与所用设备。在一些专著中均有介绍,Zinkernagel的报告中对于所用设备也有较详说明,可供参考。     

Formation mechanism of Gongchangling high-grade magnetite deposit hosted in Archean BIF,Anshan-Benxi area,Northeastern China

Banded iron-formations are main resources of global iron ore in which high-grade ore is mainly composed of martite–goethite and hematite. They are also the major resource of iron ore in China, mainly distributing in Liaoning and Hebei Province. In China, the iron ore with Fe greater than 50% is classified as high-grade iron ore. The high-grade iron ore mainly consists of magnetite and displays its unique characteristics. Gongchangling iron deposit is one typical BIF-iron deposit which contains 150 Mt of high-grade iron ore in China. The high-grade magnetite ore bodies mainly occur around magnetite quartzite, faults and the cores of folds and show positive relation to the development of the “altered rocks” in this deposit. This research shows that high-grade magnetite comes from magnetite quartzite and they are both formed, with little or no addition of aluminum-containing detrital material, by marine chemical deposition in reduced environment and they are closely related to seafloor hydrothermal activity.Muddy–silty rocks are original rocks of “altered rocks”, of which the primitive mantle normalized REE pattern, except Eu, is consistent with that of iron ore, reflecting that their formation is related to the formation of high-grade magnetite ore. Therefore, the formation mechanism of high-grade iron ore is proposed as following: the regional metamorphism provides storage space for the formation of high-grade magnetite ore and required temperature and pressure conditions for the mineral transformation; the regional metamorphic hydrothermal fluid leaches FeO out of magnetite quartzite when it passes by; and the FeO that leached out moves near faults or cores of folds together with the metamorphic hydrothermal fluid and aluminum-containing rocks, of which the original rocks are muddy–silty; in the formation of high-grade iron ore, aluminum-containing rock appears in the intervals of sedimentation of iron-containing rock series and consumes the silicon leached out of magnetite quartzite and forms garnet, chlorite, and biotite.     

Piezoelectric effects in quartz-rich rocks

Piezoelectricity, a polarization of charge produced by an applied stress, occurs in many minerals. It is particularly strong in quartz. Aggregates of piezoelectric grains are themselves piezoelectric if the grains are suitably aligned. Such aggregates may be said to have a piezoelectric fabric. Thus quartz-rich rocks may possess a piezoelectric fabric and this paper discusses the various possible fabrics.To test whether a piezoelectric fabric might be detected in a quartz-rich rock, apparatus was built that hydraulically applied a sinusoidal stress to cubic specimens. The three resulting orthogonal polarizations of charge were measured via a charge amplifier. A specimen of pure quartz was used to verify the experimental method and to ensure that absolute piezoelectric moduli were being measured. Rocks with and without preferred orientation were tested. Of the latter types, those containing little or no free quartz (marble, basalt) did not exhibit measurable piezoelectric effects. However, all quartz-rich rocks (quartzites, granites, gneisses, mylonites) did show piezoelectric effects when stressed. These effects were in two categories

1. (1) effects due to piezoelectric fabrics, called true piezoelectric effects

2. (2) effects due to random distributions of the piezoelectric vectors, called statistical effects.

To distinguish between these two effects, three criteria were used. Firstly, the measured effects were compared with the expected statistical effect for a rock of that grain size and composition. Secondly, where possible, multiple specimens were cut from the one rock sample, all specimens with the same orientation. Specimens from a rock with a piezoelectric fabric should show similar results. Thirdly, the optically observed c-axis distribution and orientation was compared with the piezoelectrically predicted fabric and orientation.This paper shows that while most rocks gave results consistent with statistical effects from a non-polar or random distribution, some rocks exhibited a true piezoelectric effect due to fabric. This effect may be used, with some imprecision, to locate the a-axes and c-axes of quartz in the aggregate. The polarities of the a-axes are also obtained.     

Rhenium in porphyry copper deposits of the urals

The overwhelming majority of porphyry Mo-Au-Cu deposits in the Urals are related to the low-K quartz diorite minor intrusions of the island-arc type, which were formed from Silurian Middle-Late Carboniferous. In the South Urals, the Cu/Mo ratio of ore decreases eastward along with enrichment in Re. At the same time, molybdenite is depleted in this metal in compliance with more sialic crust and potassium content in ore-bearing dioritic rocks. Quartz diorites at the highest-Re deposits contain 1–2 wt % K₂O. At most Early-Middle Devonian deposits and occurrences of the western Tagil-Magnitogorsk-West Mugodzhary femic megazone, molybdenite is sporadic. The Re content in rocks was mainly determined using the kinetic method and to a lesser extent with ICP-MS. A Cameca SX-100 microprobe was also used for study of molybdenite. The Cu/Mo ratio of ore exceeds 600; the Mo content is commonly 1–15 ppm (occasionally up to 30 ppm and higher); the Re content is up to 0.01–0.04 ppm, sporadically increasing to 0.08–0.17 ppm. At the same time, the Re content in molybdenite often reaches 0.2–0.4 wt %. The highest Re concentration was established in the ore of the largest Mikheevsky deposit formed in the Late Devonian-Early Carboniferous and localized in the easternmost part of the East Ural sialic-femic megazone. The Re content in the orebodies of this deposit often reaches 0.2–0.5 ppm (up to 1.4–2.7 ppm) and 0.21 wt % in molybdenite. The average Mo grade of ore is 80 ppm and Cu/Mo ratio is 66. These data and Sr isotopic composition of ore-bearing granitoid and metasomatic rocks [(⁸⁷Sr/⁸⁶Sr)_t = 0.7038–0.7051; (?_Nd)_t = 3–7] testify to the mantle source of matter with insignificant admixture of crustal material. The same is apparently valid for Re and Cu in contrast to Mo. This statement is corroborated by the inverse correlation between Cu/Mo and Mo/Re ratios in the ore. Fluid-crystal fractionation of ore-bearing dioritic rocks is accompanied by enrichment of ore in Mo and by decrease in Re content in molybdenite. In the Tarutino ore field, the pyrite-chalcopyrite mineralization gives way to the molybdenite mineralization in line with in-sequence intrusion of diorite with quartz-bearing groundmass and granodiorite porphyry. Because of increasing silica content in granitoids, the Re concentration in molybdenite commonly remains below 0.07 wt % as is noted at the rare deposits localized in the sialic megazones.     

Re-interpretation of a mixed petrographic province — The Sintra intrusive complex (Portugal) and related rocks

Sub-alkaline to calc-alkaline granite dominates the high-level plutonic massif of the Serra de Sintra, while two overlapping ring complexes recognised within it consist of four distinct alkaline to sub-alkaline quartz-bearing syenitic units, together with intrusions of a remarkable kaersutite- and (titan?)biotite-bearing theralite heteromorph (Mafraite), contaminated to varying degrees by sialic admixture. Large volumes of sub-volcanic breccia testify to considerable late explosive activity in and near the ring centres. Minor intrusives are approximate compositional counterparts of the plutonic rocks, but more closely resemble lavas forming the extensive “basaltic mantle” of the Lisbon region, where compositions range from olivine basalt, basanite and theralite (luscladite) to subordinate quartz-bearing trachyandesite and trachyte. Undersaturated salic rocks are absent throughout the province. Magmatic differentiation probably played a minimal part in petrogenesis of the Sintra intrusives. The granite is interpreted as a direct product of basement syntexis, the other rocks as products of selective palingenetic reactions between mafraitic magma and crystalline basement (or granite). Evolution of the volcanic and hypabyssal rocks may have been controlled by similar reactions, but evidence favouring differentiation of this suite from sialcontaminated basic parents is almost as strong. There are some points of resemblance between this province and that of the Auvergne region in southern France.     

埃达克岩及其成矿作用和相关问题的讨论

本文初步探讨了埃达克岩与相关大型矿床的关系，指出与埃达克岩浆有关的分异同化作用在一定条件下可以形成大型矿床；同时也强调了成矿后矿床保存的重要性。由于造山带的剥蚀速率快，导致和埃达克岩浆演化密切相关的形成于地壳浅部的大型斑岩矿床的保存有时限。因此在中国东部及“三北”地区中生代以前的造山带中，埃达克岩能否作为寻找相关大型矿床的标志值得商榷；但在新生代的西藏地区则是有可能的。近十年的研究认为中国东部侏罗纪—白垩纪的类似岩石并不属于埃达克岩系列，而是橄榄安粗岩及高钾钙碱性岩石系列。它们主要来源于富集地幔的部分熔融(不排除有下地壳物质混染的可能)及其后的结晶分异；一些中生代的斑岩型铜—金矿床和浅成低温热液矿床与此有关。