A highly sensitive LITES sensor based on a multi-pass cell with dense spot pattern and a novel quartz tuning fork with low frequency

A highly sensitive light-induced thermoelectric spectroscopy(LITES)sensor based on a multi-pass cell(MPC)with dense spot pattern and a novel quartz tuning fork(QTF)with low resonance frequency is reported in this manuscript.An erbi-um-doped fiber amplifier(EDFA)was employed to amplify the output optical power so that the signal level was further enhanced.The optical path length(OPL)and the ratio of optical path length to volume(RLV)of the MPC is 37.7 m and 13.8 cm^(-2),respectively.A commercial QTF and a self-designed trapezoidal-tip QTF with low frequency of 9461.83 Hz were used as the detectors of the sensor,respectively.The target gas selected to test the performance of the system was acetylene(C2H2).When the optical power was constant at 1000 mW,the minimum detection limit(MDL)of the C2H2-LITES sensor can be achieved 48.3 ppb when using the commercial QTF and 24.6 ppb when using the trapezoid-al-tip QTF.An improvement of the detection performance by a factor of 1.96 was achieved after replacing the commer-cial QTF with the trapezoidal-tip QTF.

Diffusion and reaction mechanism of limestone and quartz in fluxed iron ore pellet roasting process

The increase to the proportion of fluxed pellets in the blast furnace burden is a useful way to reduce the carbon emissions in the ironmaking process.In this study,the interaction between calcium carbonate and iron ore powder and the mineralization mechanism of fluxed iron ore pellet in the roasting process were investigated through diffusion couple experiments.Scanning electron microscopy with energy dispersive spectroscopy was used to study the elements’diffusion and phase transformation during the roasting process.The results indicated that limestone decomposed into calcium oxide,and magnetite was oxidized to hematite at the early stage of preheating.With the increase in roasting temperature,the diffusion rate of Fe and Ca was obviously accelerated,while the diffusion rate of Si was relatively slow.The order of magnitude of interdiffusion coefficient of Fe_(2)O_(3)-CaO diffusion couple was 10^(−10) m^(2)·s^(−1) at a roasting temperature of 1200℃for 9 h.Ca_(2)Fe_(2)O_(5) was the initial product in the Fe_(2)O_(3)-CaO-SiO_(2) diffusion interface,and then Ca_(2)Fe_(2)O_(5) continued to react with Fe_(2)O_(3) to form CaFe_(2)O_(4).With the expansion of the diffusion region,the sillico-ferrite of calcium liquid phase was produced due to the melting of SiO_(2) into CaFe_(2)O_(4),which can strengthen the consolidation of fluxed pellets.Furthermore,andradite would be formed around a small part of quartz particles,which is also conducive to the consolidation of fluxed pellets.In addition,the principle diagram of limestone and quartz diffusion reaction in the process of fluxed pellet roasting was discussed.

Etching of quartz crystals in liquid phase environment:A review

Quartz crystals are the most widely used material in resonant sensors,owing to their excellent piezoelectric and mechanical properties.With the development of portable and wearable devices,higher processing efficiency and geometrical precision are required.Wet etching has been proven to be the most efficient etching method for large-scale production of quartz devices,and many wet etching approaches have been developed over the years.However,until now,there has been no systematic review of quartz crystal etching in liquid phase environments.Therefore,this article provides a comprehensive review of the development of wet etching processes and the achievements of the latest research in thisfield,covering conventional wet etching,additive etching,laser-induced backside wet etching,electrochemical etching,and electrochemical discharge machining.For each technique,a brief overview of its characteristics is provided,associated problems are described,and possible solutions are discussed.This review should provide an essential reference and guidance for the future development of processing strategies for the manufacture of quartz crystal devices.

Unveiling Nb-Ta mineralization processes:Insight from quartz textural and chemical characteristics in the Songshugang deposit,Jiangxi Province,South China

The Songshugang deposit is a large Ta-Nb deposit in South China,with Ta-Nb mineralization associated genetically with the granite and pegmatite.A diversity of quartz from topaz-albite granite,quartz-mica pegmatite,quartz-feldspar pegmatite,and quartz-fluorite pegmatite at Songshugang was studied by CL and LA-ICP-MS in order to constrain enrichment mechanisms of Nb and Ta and to find geochemical indicators of quartz for rare metal deposits.Cathodoluminescence image illuminates a canvas of complexity,the quartz from topaz-albite granite,quartz-mica pegmatite,quartz-feldspar pegmatite,and quartz-fluorite pegmatite,exhibits numerous dark CL streaks,patches,and a series of healed fractures.These textures suggest that the rocks were fractured because of deep crustal pressure,and underwent later hydrothermal metasomatism and quartz filling.The quartz from quartz-fluorite pegmatite present limited patches or fractures but distinct growth bands,indicating that the melt fluid composition during the formation of quartz at this stage varies greatly and is less aff ected by mechanical fragmentation.The LA-ICP-MS analysis of quartz shows that there is a positive correlation between Al and Li in the quartz from topaz-albite granite,quartz-mica pegmatite,quartz-feldspar pegmatite,to quartz-fluorite pegmatite,indicating that Al mainly enters the quartz lattice through charge compensation substitution mechanism with Li.However,our data deviate from the theoretical Li:Al mass ratio of~1:3.89 in quartz,indicating that there may be competition between H^(+)and Li in a water-rich magmatic environment.The quartz from topaz-albite granite is enriched in K and Na elements,and the quartz from quartz-fluorite pegmatite is enriched in fluorite with a low Ca content in quartz,further elucidating that these rocks were subjected to hydrothermal metasomatism.From topaz-albitite granite to quartz-fluorite pegmatite,Al,Li and Ge content and Al/Ti,Ge/Ti,Sb/Ti ratios in quartz gradually increased,but Ti content gradually decreased,reflecting the high evolution of magma,which can enrich rare metal elements.Based on the characteristics of quartz CL textures and trace elements in topaz-albite granite,quartz-mica pegmatite,quartz-feldspar pegmatite,and quartz-fluorite pegmatite,combined with the albitization and K-feldspathization of rocks,it is suggested that the Nb-Ta mineralization in Songshugang may be influenced by the combined action of magmatic crystallization differentiation and fluid metasomatism.By comparing the quartz in the Songshugang pluton with the quartz in the granite type and pegmatite type rare metal deposits recognized in the world,the Songshugang pegmatite share similarities with the LCT-type pegmatite.Combined with previous studies,the Ge/Ti>0.1 and Ti<10 ppm,as well as Al,Li,Ge,Sb,K,Na contents and Al/Ti,Sb/Ti ratios in quartz have the potential to be a powerful exploration marker for identifying granite-like pegmatitic Nb-Ta deposits in other places.

Trace elements in magmatic and hydrothermal quartz:Implications on the genesis of the Xingluokeng Tungsten Deposit,South China

The Xingluokeng deposit is the largest gran-ite-related tungsten deposit within the Wuyi metallogenic belt in South China.The Xingluokeng intrusion primarily consists of porphyritic biotite granite,biotite granite,andfine-grained granite.The deposit is represented by veinlet-disseminated mineralization with K-feldspathization and biotitization,alongside quartz-vein mineralization with gre-isenization and sericitization.This study investigates in-situ analyses of quartz compositions from both the intrusion and hydrothermal veinlets and veins.Trace element correlations indicate that trivalent Al^(3+)and Fe^(3+)replace Si^(4+)within the quartz lattice,with monovalent cations(such as Li^(+),Na^(+),and K^(+))primarily serving as charge compensators.Low Ge/Al ratios(<0.013)of quartz from granites suggest a mag-matic origin.The low Al/Ti and Ge/Ti ratios,accompanied by high Ti contents in quartz,suggest that the porphyritic biotite granite and biotite granite are characterized by rela-tively low levels of differentiation and high crystallization temperatures.In contrast,thefine-grained granite exhibits a higher degree of fractionation,lower crystallization tem-peratures,and a closer association with tungsten miner-alization.Ti contents in quartz from quartz veins indicate Qz-Ⅰformed at temperatures above 400°C,while Qz-Ⅱto Qz-Ⅴformed at temperatures below 350°C.Variations in different generations of quartz,as indicated by Al content and(Al+Fe)/(Li+Na+K)ratio,suggest that Qz-Ⅰprecipi-tated from a less acidicfluid with a stable pH,whereas Qz-Ⅱto Qz-Ⅴoriginated from a more acidicfluid with notable pH variations.Consequently,alkaline alteration and acidic alteration supplied the essential Ca and Fe for the precipita-tion of scheelite and wolframite,respectively,highlighting a critical mechanism in tungsten mineralization at the Xin-gluokeng deposit.

Synergistic strengthening mechanism of Ca^(2+)-sodium silicate to selective separation of feldspar and quartz

Inhibitors are important for flotation separation of quartz and feldspar.In this study,a novel combined inhibitor was used to separate quartz and feldspar in near-neutral pulp.Selective inhibition of the combined inhibitor was assessed by micro-flotation experiments.And a series of detection methods were used to detect differences in the surface properties of feldspars and quartz after flotation reagents and put forward the synergistic strengthening mechanism.The outcomes were pointed out that pre-mixing combined inhibitors were more effective than the addition of Ca^(2+)and SS in sequence under the optimal proportion of 1:5.A concentrate from artificial mixed minerals that was characterized by a high quartz grade and a high recovery was acquired,and was found to be 90.70wt% and 83.70%,respectively.It was demonstrated that the combined inhibitor selectively prevented the action of the collector and feldspar from Fourier-transform infrared(FT-IR)and adsorption capacity tests.The results of X-ray photoelectron spectroscopy(XPS)indicated that Ca^(2+)directly interacts with the surface of quartz to increase the adsorption of collectors.In contrast,the chemistry property of Al on the feldspar surface was altered by combined inhibitor due to Na^(+)and Ca^(2+)taking the place of K^(+),resulting in the composite inhibitor forms a hydrophilic structure,which prevents the adsorption of the collector on the surface of feldspar by interacting with the Al active site.The combination of Ca^(2+)and SS synergically strengthens the difference of collecting property between quartz and feldspar by collector,thus achieving the effect of efficient separation.A new strategy for flotation to separate quartz from feldspar in near-neutral pulp was provided.

Rb-Sr Isotopic Chronology of the Au-Bearing Quartz Veins in Gold Deposits in the Eastern Part of North China Platform

In the eastern part of China there had occurred large\|scale gold mineralization during the Mesozoic, resulting in a large number of important gold ore\|concentrated areas. In this paper we have selected some isotope data (including four gold deposits previously studied and two gold deposits in this work) of Au\|bearing quartz veins of the representative gold deposits in six important gold ore\|concentrated areas in the periphery of the North China Platform and calculated their metallogenic ages using the method of Ludwig (2.90 version). The results show that the representative gold deposits in the six gold ore\|concentrated areas were formed during the Mesozoic.

A Study of High-Temperature and High-Pressure Experiment of Correlativity between Deformational System of Au-Bearing Rocks and Element Adjustment

Modelling of migration and accumulation of elements Au and Ag in rocks under temperatures of 350–450°C and a confining pressure of 300 MPa and axial pressure of 100–150 MPa is conducted. It is found that the contents of gold and silver get higher in metallic sulphides such as pyrite, chalcopyrite and sphalerite as well as in quartz and muscovite, and get lower in chlorite, biotite, seriate, albite and calcite, showing that tectono-dynamics is one of the important factors for petrogenesis and metallogenesis.

Novel polyhydroxy cationic collector N-(2,3-propanediol)-Ndodecylamine: Synthesis and flotation performance to hematite and quartz

To enhance the performance of traditional cationic collector,a novel polyhydroxy amine collector N-(2,3-Propanediol)-N-dodecylamine(PDDA)was designed by introducing one propylene glycol group into dodecylamine(DDA).It was prepared by a nucleophilic substitution reaction,which showed better solubility and hydrophobicity than DDA and was firstly employed as the collector for the separation of hematite and quartz.Flotation tests showed that PDDA had an excellent flotation performance and significantly better selectivity than DDA.In addition,the flotation performance and adsorption mechanism of PDDA on hematite and quartz surfaces were studied using Fourier transform infrared spectroscopy(FTIR),zeta potential and X-ray photoelectron spectroscopy(XPS)tests.These results demonstrated that the interaction between PDDA and the minerals’surfaces was mainly electrostatic adsorption and hydrogen bond,while PDDA tended to adsorb on the surfaces of quartz more than that of hematite.Performance optimization of amine collectors by introducing hydroxyl was also verified,which was of great meaning to the design,development,and application of the polyhydroxy cationic collector.In conclusion,PDDA could be used as a potential collector in the flotation separation of quartz and hematite.

Geochronology,Geochemistry and Petrogenesis of the Bangbule Quartz Porphyry:Implications for Metallogenesis

The Bangbule skarn lead-zinc(Pb-Zn)deposit(>1 Mt Zn+Pb)is located in the western Nyainqentanglha polymetallic metallogenetic belt,central Tibet.Lenticular orebodies are all hosted in skarn and developed in the contact zone between the quartz porphyry and carbonate strata of the mid Paleozoic Middle to Upper Chaguoluoma Formation as well as in carbonate and sandstone beds of the Upper Paleozoic Laga Formation.As a newly discovered skarn deposit,the geological background and metallogenesis of this deposit remain poorly understood.Detailed petrological,geochemical and geochronological data of the ore-related quartz porphyry,helps constrain the mineralization age and contributes to discussion on the ore genesis of the Bangbule deposit.Both endoskarn and exoskarn are identified in the Bangbule deposit.From quartz porphyry to carbonate formation,the exoskarn is zoned from proximal garnet skarn to distal pyroxene skarn.Zircon U-Pb dating results show that the quartz porphyry formed at 73.9±0.8 Ma.Geochemical analysis results show that the quartz porphyry has high contents of SiO_(2)(71.40–74.94 wt%)and K_(2)O+Na_(2)O(3.76–8.46 wt%)with A/CNK values of 0.69 to 1.06.Besides,the quartz porphyry is enriched in large ion lithophile elements(LILEs)and light rare earth elements(LREEs)and have lowεNd(t)(from-8.25 to-8.19)and high initial(^(87)Sr/^(86)Sr)i values(0.713611–0.714478).Major,trace elements and whole-rock F concentration analysis results from the endoskarn samples show higher TFe_(2)O_(3),MgO,CaO,Pb+Zn,W,Sn,Mo and F etc.,and lower alkalis(K_(2)O,Na_(2)O,Sr and Ba)than those of fresh quartz porphyry,indicating that the early ore-forming fluids were an Ca-Fe-F-enriched fluid.Massive ore in the proximal skarn might be related to the high F content in the magma,which lowered the solidus temperature of the quartz porphyry magma and caused a lower temperature of the ore-forming fluids,as well as facilitating the precipitation of sphalerite and galena.Based on the geochemical characteristics presented in this study,we propose that the ore-related quartz porphyry was formed by partial melting of crust materials with some juvenile crustal component input.The partial melting of the middle-upper crust after the initial enrichment of lead and zinc elements are important for the formation of Pb-Zn deposits.The case study of the Bangbule deposit has proven that there is still a crust-derived magmatic source region in the western segment of the central Lhasa terrane.Therefore,there is still great potential for Pb-Zn mineralization and Pb-Zn exploration.

基于Quartz.NET的任务调度系统在医院信息化中的应用研究

文章探讨了Quartz.NET任务调度系统在医院信息化中的应用。通过对任务调度系统的介绍和Quartz.NET的特点分析,文章提出了基于Quartz.NET的任务调度系统在医院信息化中的应用方案,主要包括任务调度系统的设计和实现、任务执行监控和报警机制的建立等方面。该方案在实际应用中,有效提高了医院信息化系统的运行效率和管理水平,减轻人工负担,提高医院服务水平,具有较高的实用价值和推广意义。

Hematization of Quartz Grains: Study of the Surface of Quartz Grains (M.E.B) and Semi-Quantitative Mineralization

Interest in the Côte d’Ivoire sedimentary basin has led to numerous investigations. All these investigations are aimed at understanding the functioning of the basin and a paleogeographic approach including sediment transport dynamics. However, the use of exoscopy and semi-quantitative mineralogy has been little developed. This study was carried out to compensate for this lack of interest in these methods. Its aim is to understand the transformation of quartz into hematite using exoscopy and semi-quantitative mineralogy in the Adiaké locality, in the eastern onshore basin of Côte d’Ivoire. Two methods were applied to 250 μm-diameter quartz grains from the 40 m coasts. Exoscopy provides information on microscopic texture, surface and corrosion, as well as determining the transport mechanism and deposition phases of quartz grains. Semi-quantitative mineralogy provides an estimate of the weight percentages of major element oxides and the ultrastructure of quartz grains. Exoscopy showed that these grains had been subjected to torrential fluvial transport. They were marked by mechanical and chemical traces during this transport and evolved in different environments. Semi-quantitative mineralogy shows the existence of negative and positive correlations between oxides. Negative correlations indicate a substitution, in order of importance, of silicon by iron, phosphorus and aluminum in these quartz. Positive correlations show that there is no substitution between the oxides concerned in these quartz grains. Divo’s quartz grains have recorded several mechanical and chemical microstructures of their sedimentary episodes, with the appearance of iron nodules in the ports left by silica.

Compensation of Parasitic Capacitance of Quartz Tuning Fork in AFM

We have built an atomic force microscope using a quartz tuning fork as sensor. The excitation method we adopted, the electrical excitation, introduces stray capacitance into the signal-processing circuit. In this report, we demonstrated a simple but effective method to compensate for this parasitic capacitance by adding a compensator circuit consisting of an inverting amplifier and a capacitor. The capacitor is connected in series with the inverting amplifier and the compensator is connected in parallel with the quartz tuning fork. The resonance curve of the system measured after adding the homemade compensator resembles that of a pure RLC circuit, meaning that the stray capacitance is successfully eliminated. Furthermore, we tried to use our equipment to measure PDMS sample and got clean data. This system can be further combined with confocal microscope and diamond with NV defect to build scanning NV magnetometry.

关于高纯石英原料矿石地质学评价方法的探讨

高纯石英资源是一种重要的战略性资源。本文结合高纯石英成矿地质特征及其对后期选矿提纯、材料加工等的影响,系统总结了高纯石英原料中杂质的赋存状态、形成机理以及评价方法等,得出:(1)可以作为高纯石英原料的潜在岩石类型有花岗伟晶岩(包括不含暗色矿物的伟晶状花岗岩)、脉石英以及水晶,岩浆演化晚期的伟晶状花岗岩-伟晶岩早期阶段的NYF型花岗伟晶岩结晶形成的石英纯度更高,后期适当的变形变质作用更有利于高纯石英矿床的形成。高纯石英原料矿石中石英矿物呈现无色透明至半透明,矿物构造裂隙少,伟晶岩型矿石矿物组成通常为石英、钠长石、条纹长石、白云母等,黑云母等暗色矿物含量极少,基本不见锂辉石、独居石等稀有金属矿物和电气石、萤石等含挥发分矿物。(2)影响高纯石英的主要地质因素包括脉石矿物及晶界杂质、包裹体、晶格杂质等。其中包裹体类型、数量和尺寸是包裹体评价的关键指标,天然石英矿物中的气液两相包裹体、矿物包裹体和<10μm包裹体应尽量少;Al和Ti是晶格杂质元素评价标志性元素,通常要求天然石英矿物中Al<50×10-6和Ti<10×10-6。(3)建议按照手标本特征-石英矿物特征-石英中包裹体特征-晶格元素赋存状态及含量的顺序,从宏观到微观,综合借助光学显微镜、扫描电子显微镜(SEM)、阴极荧光光谱分析系统(SEM-CL)、激光剥蚀电感耦合等离子质谱仪(LA-ICP-MS)等开展地质学评价和研究工作。

Influence of vacuoles with gas–liquid inclusions on the thermobaric destruction conditions of natural quartz under dynamic heating in an RF-TICP torch system

In the present work,the turbulent mixing process of a polydisperse quartz particle flow with a plasma stream generated by a radio-frequency(RF)inductively coupled plasma torch was numerically studied.The thermobaric stress in the quartz particles under dynamic heating in a heterogeneous plasma flow was determined by a two-stage approximation approach.The effect of the presence of vacuoles in natural quartz on the particle thermobaric destruction conditions was studied.It was found that the equivalent thermal and baric stresses in quartz particles may significantly increase in the presence of vacuoles within a small gas volume fraction.The influence of the regime and energetic working conditions of an RF inductively coupled plasma torch system on the particle thermobaric destruction conditions was examined,and a recommendation was given to promote the degree of thermobaric destruction of quartz particles,which is of substantial importance for improving the overall enrichment efficiency of quartz concentrates.

β-FeOOH/SiO_(2)复合非均相Fenton催化剂制备及对甲基橙溶液的降解

采用简单、环保的方法合成β-FeOOH/SiO_(2)复合非均相Fenton催化剂,采用红外光谱仪(FT-IR)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、透射电子显微镜(TEM)对催化剂进行表征分析,考察质量比、合成温度和合成时间对催化剂催化活性的影响,通过分析催化剂类型、用量及双氧水用量,探究β-FeOOH/SiO_(2)复合催化剂处理染料废水的最佳工艺条件。结果表明:β-FeOOH/SiO_(2)复合催化剂制备工艺简单,操作条件温和,易于工业化生产;β-FeOOH/SiO_(2)复合催化剂在满足m(β-FeOOH)/m(SiO_(2))=1∶1,反应温度为90℃,反应时间为8 h时,具有最佳的催化活性;在30℃条件下,β-FeOOH/SiO_(2)的加入量为5 g/L,过氧化氢的加入量为0.1 L/L时,200 mg/L甲基橙染料废水的去除率最大,达到98.85%,对亚甲基蓝和罗丹明B的去除率分别达到90.44%和99.25%;β-FeOOH/SiO_(2)复合催化剂对染料废水具有良好的降解效果。

我国石英资源的开发利用特点及应用进展

石英资源是重要的基础性非金属矿产资源,广泛用于玻璃、机械铸造、电子电工、冶金、耐火材料、化工、陶瓷等领域,不同行业对石英砂的技术要求和用量各不相同,宏观了解石英资源的开发利用特点和市场应用对石英资源的高效合理利用意义重大。介绍了我国各类石英资源的资源现状、不同类型矿石的开发利用特点及主要应用方向,详细总结了玻璃、高纯石英、机械、电子电工、冶金、耐火材料、化工、陶瓷、石油、板材等不同领域对石英原料的标准技术要求和产品特点;从石英资源开发利用全领域角度出发,系统梳理了不同领域石英资源的用量及产值,详细分析了高纯石英市场现状及供需发展趋势。结合石英资源开发利用现状,提出了在石英资源的开发利用过程中应分类评价、分级利用等对策建议,以期进一步提高我国石英资源开发利用水平和保障能力。

石英玻璃气孔成因与原料晶体特征的相关性

气孔是影响石英玻璃品质的主要结构缺陷,为了探究其成因与原料石英晶体特征的关系,选择5种产自于国内外不同地区的优质脉石英为研究对象,采用偏光显微镜、ICP及XRD等仪器及方法分析不同脉石英晶体性质、包裹体特征及石英砂纯度,比较各高温熔体表观特征、原料表面与玻璃体气孔内外硅氧元素分布状态。结果显示,原生包裹体少、晶格缺陷少、结晶度高,则熔体气孔少,石英玻璃透明度高;反之,熔体气孔多,石英玻璃透明度低。石英晶体内大量微细原生包裹体是石英玻璃气孔形成的主要因素;晶格缺陷与结晶度紧密相关并可遗传,石英砂纯度与熔体气孔形成无直接关系,但晶格杂质的存在会导致晶格缺陷。

花岗伟晶岩分异演化与含矿性评价——从造岩矿物组构视角

高演化稀有金属伟晶岩的成矿过程是复杂和苛刻的,涉及到岩浆-热液过程热历史、岩浆迁移路径与成矿空间、侵位环境的过冷程度以及岩浆组分中稀有金属元素的初始富集等条件。而伟晶岩的分带特征是其形成过程的一种综合体现,不论是伟晶岩区域分带还是伟晶岩内部结构分带,都反映了伟晶岩岩浆结晶分异过程中岩浆的性质与形成环境,而这同时也赋予了造岩矿物在组构上的特殊性,形成遗传代码,对其进行解密,从而能够用于示踪与评估花岗伟晶岩的演化程度与成矿潜力。对于区域伟晶岩群的成矿潜力评估,由于含矿熔体在组分上的跨度较大,随着远离母体花岗岩体距离的增大,伟晶岩群演化程度增加,熔体中铁镁质组分以及Ca、Ba、Sr等碱土金属含量迅速降低,而挥发分、助熔剂组分、碱金属含量在残余熔体中逐渐增加,长石、云母与石英在类别和组构上产生显著变化;其中长石向钾-钠端元演化,且钠长石相对钾长石占据主导地位,云母由黑云母向白云母以及锂白云母转变,石英阴极发光特征与晶体结构及微量元素成分也表现出规律性的变化。受矿物晶格的限制,长石的K/Rb、K/Cs以及云母的K/Rb、K/Cs、Nb/Ta等比值特征能有效区分不同矿化潜力的伟晶岩群。石英的阴极发光特征能够揭示其生长环境与历史,石英的Li、Al、Ti、Ge等微量元素组成可以用来区分不同类型的伟晶岩矿床,并提供关于岩浆演化和成矿过程的重要线索。伟晶岩内部分带的形成主要受成矿熔体规模、过冷度以及成矿空间的封闭性等因素的控制,但在初始熔体成分上可以具有较大的变化。其中强分带型稀有金属伟晶岩记录了完整的岩浆-热液演化过程,不同阶段石英、长石和云母在晶体形态、微观结构以及微量元素组成上都具有显著变化。弱分带型稀有金属伟晶岩(钠长石-锂辉石伟晶岩)的造岩矿物组分在伟晶岩内部变化不大,其受构造控制明显,在空间上与贫矿伟晶岩之间可具有较大的矿物组成差异,表明二者之间存在流动分异过程。而长距离(以更厚的地壳或大型拆离断层为标志)的熔体迁移正是形成超大型伟晶岩稀有金属矿床的有利要素。

鄂尔多斯盆地太原组砂岩缝合线特征及成因

鄂尔多斯盆地北缘太原组砂岩中广泛发育缝合线构造,缝合线成因机理复杂,且会对砂岩储层的物性产生重要影响。基于岩芯观察,并通过能谱、扫描电镜、X衍射及铸体薄片等综合分析,揭示了太原组砂岩缝合线的几何形态、矿物组成及其成因机理。研究表明,太原组砂岩缝合线振幅大小差异明显,可划分出波浪型、尖峰型、长方柱型、复合型及网状交织型5种类型。缝合线物质组成主要包括有机碳、石英、伊利石、高岭石、黄铁矿、金红石和锆石,黏土矿物中伊利石的含量远高于围岩,而高岭石含量远低于围岩。缝合线内有机质与黏土矿物具有典型的沉积成因标志,它们可以作为硅质迁移与沉淀的催化剂,导致缝合线内及两侧砂岩孔隙中的硅质沉淀和碎屑石英颗粒的增生。这些缝合线构造是埋藏过程中沉积有机质压溶的产物,是沉积黏土矿物与有机质成岩作用的综合响应。缝合线相关的硅质沉淀与石英加大是研究区太原组石英砂岩致密的主要因素,但沿缝合线易发育裂缝,起到改善岩石渗透性的作用。