干旱荒漠区隐伏金矿覆盖层中金的分布与迁移：以新疆金窝子金矿田210金矿带为例

以新疆金窝子金矿田210金矿带为例,实验研究了该区地气和土壤活动态测量等深穿透地球化学方法的效果。实验表明地气测量和土壤活动态测量可以有效地反映覆盖层下隐伏矿体。揭露矿体覆盖层的钻孔研究表明,金活动态形式具有“C”型分布特征。采集矿体上方地表异常位置土壤孔隙中地气、土壤样品,使用透射电子显微镜(TEM)实测样品中微粒物质的粒径、形貌和成分,在地气和土壤中观测到了Au-Cu、Au-Bi成矿元素纳米微粒,此微粒是形成地表深穿透地球化学异常的物质,来源于覆盖层下隐伏矿体。微粒到达地表,可以形成地气和土壤活动态异常。纳米微粒具有可从土壤颗粒表面分离的性质,在其向上迁移过程中,可以从吸附固定状态解吸,此性质可以用于解释活动态异常在钻孔垂直剖面上的“C”型分布。     

贵州关岭丙坝铜矿床地气微粒特征

为了查明地气微粒特征与隐伏矿体的关系,对贵州关岭丙坝铜矿床进行地气微粒采样,并用透射电子显微镜进行分析。研究结果表明:地气微粒存在形式有微粒聚合体和单个微粒,以微粒聚合体为主。单个微粒形态各异,有球状、板状、立方状、椭球状、条状、不规则状等,粒度一般在几纳米到300nm之间;微粒聚合体多呈链状、浑圆状、不规则状。微粒的元素组成与地下隐伏矿体具有较好的相关性,且发现较多微粒中含有高浓度的Fe、Mn、Pb、Zn等元素,这无疑对该矿区今后的地质找矿具有指导意义。此外,通过对比不同矿床的地气微粒特征,发现矿床类型不同,微粒的种类、成分、形态等特征有差异,但相同类型的矿床却具有较大相似性。矿床地气微粒特征与地下隐伏矿床具有较好相关性,在相似地质环境下形成的矿床微粒元素组成、大小大体上具有相似性,但其间的微粒组合、形态等仍会存在一定的差异性。因此,可以通过对隐伏金属矿床地气微粒特征的研究,建立不同矿床类型地气微粒特征模型。     

冲积平原区隐伏金属矿地气法试验研究

文章通过冲积平原区(山东王家庄铜矿区)的地气试验研究及其与常规土壤测量结果的对比,总结了冲积平原区隐伏金属矿矿床上方地气元素的分布特征.研究结果认为:①在不同覆盖条件、常规土壤测量无效的情况下,地气测量均可发现清晰的金属元素异常,异常强度高,且与矿体空间位置相吻合;显示出地气法在厚覆盖条件下对隐伏金属矿的独特作用;②液...     

地气测量在内蒙老羊壕金矿区的某些试验成果

以内蒙老羊壕金矿区为试验基地,引进抽气法地气测量,探讨了地气测量在内蒙干旱荒漠区寻找浅覆盖区隐伏金矿床的有效性。并以试验资料为依据,初步探讨了抽气法地气测量中的若干问题,指出了抽气法地气测量中存在微尘颗粒干扰。对寻找隐伏金矿床的多元素地气测量,采用经0.22μm微孔滤膜过滤泡沫塑料吸附为好。已有资料显示可能有超微粒(接近纳米级)物质自深部矿体迁移上来。     

申家窑金矿床地气测量异常特征

河南申家窑金矿床属典型的蚀变破碎带型金矿,矿区大部分被第四系沉积物所覆盖。文章通过偏光显微镜与扫描电子显微镜观察、电子探针微区分析、矿石成分化学分析等方法,认为申家窑金矿床的主要金矿物为自然金和银金矿,主要载体矿物为石英、黄铁矿和方铅矿。作者在总结矿床矿物学特征的基础上,实验研究了地气测量在该隐伏矿床上方黄土覆盖层的勘查效果。地气测量使用泡塑为捕集介质,利用surfer软件绘制元素空间分布图。元素空间分布图表明Au具有明显的地球化学异常,同时Cu、Pb、Zn等成矿伴生元素也存在异常。综合矿床矿物学的研究结果和元素空间分布特征,认为地气测量异常为矿致异常,地气异常结果能够指示深部隐伏矿体的产状。地气测量方法作为深穿透地球化学找矿方法之一,在研究区能够反映深部矿化,可以应用于黄土覆盖区寻找隐伏矿床。     

广西丹池成矿带芒场矿田岩浆岩源区特征及锆石U-Pb年龄分析

丹池成矿带是我国重要锡多金属成矿带,过去对丹池成矿带成岩成矿研究主要集中在大厂矿田及五圩矿田,而对丹池成矿带北部的芒场矿田岩浆作用时代、源区特征及其成矿性缺少分析。芒场矿田岩浆活动强烈,发育隐伏斑状花岗岩及有关的花岗斑岩脉和隐伏细粒花岗斑岩及有关的白云母花岗斑岩脉。本文分析花岗斑岩脉U-Pb年龄及花岗斑岩脉和白云母花岗斑岩脉主、微量元素组成,以探讨岩浆活动时代、岩浆源区特征及其成矿潜力。芒场矿田花岗斑岩脉锆石U-Pb年龄为89.1±0.9Ma (MSWD=0.9),和丹池成矿带内大厂矿田岩浆活动时代相近,表明丹池成矿带岩浆活动时代都发生于90Ma左右。白云母花岗斑岩脉具高A/CNK比值(2.69～2.88),含高铝硅酸盐矿物白云母及在Th-Rb图上沿S型花岗岩趋势线分布,和大厂矿田S型黑云母花岗岩的特征基本一致,表明其主要为S型花岗岩。花岗斑岩脉形成时代晚于白云母花岗斑岩脉,但其具有更低的SiO_2含量和更高的MgO、Fe_2O_3~T、CaO和TiO_2含量,且在SiO_2与TiO_2、Fe_2O_3~T、Al_2O_3和P_2O_5关系图中分布于不同区域,没有线性变化关系,显示两者不是同一岩浆结晶分异演化形成的,而为不同沉积变质岩部分熔融形成的。白云母花岗斑岩脉富Al_2O_3、K_2O、Rb、Cs、Sn、W、Nb和Ta,在Rb/Ba-Rb/Sr图上位于富粘土源区,为强风化作用形成的富粘土质富稀有金属源区部分熔融形成的产物。华南西部基底发育经强风化作用形成的富粘土质富稀有金属元素沉积变质源区,为华南西南缘大规模锡矿床的形成提供了物质基础。     

Application and Current Status of Geogas Prospecting in Concealed Uranium Deposits Exploration

The research achievements of geogas prospecting through the mechanisms of geogas prospecting and its applied research in the area of concealed uranium deposits prospecting were analyzed. Geogas prospecting is a new means of deeply concealed deposits exploration that started to develop gradually from the 1980s and is at an initial stage of research in concealed uranium deposits exploration. Furthermore, comments and suggestions were provided for following research work by summarizing the shortcomings and problems of current studies in this paper. A general upward micro-flow of geogas could carry the metal nanoparticles associated with ore body underground to the surface of earth to come into being anomaly halos of elements contents above the ore body, and with these anomaly halos, the relevant information of deeply concealed uranium deposits (or other classes of metal ore bodies) would be reflected. The depth that geogas measurement could achieve for prospecting concealed deposits under the covering layers is up to a thousand meter. Geogas prospecting can be used for investigating in small scales, surveying generally and in detail in big scales and locating the ore bodies. At the present stage, there are three primary under-mentioned problems in the studies of geogas prospecting: ①On the one hand, the researches of how mediums (covering layer) would affect the migration process of geogas are far from enough. On the other hand, appropriate mathematical theory models have not been set up yet. ②In China, there are currently few accurate and practical physical models for geogas prospecting to carry out controllable and repetitive series experiments as well as theoretical studies. It is essential that an appropriate physical model should be established timely in order to provide an experimental platform and a kind of technical assistance for the mechanism study of geogas prospecting. ③To achieve the aim of popularizing the geogas prospecting in the uranium exploration area, the research of trapping solution and sampling and measuring methods should be further developed and the methods of rapid geogas in-site measuring which are suitable for various geologic structures of uranium deposits should be made reasonably to cater to the need of rapid and accurate field measurement.     

大深度隐伏多金属矿地气探测试验

以广西大厂矿区内埋深超过800 m的95号锌铜矿体为研究对象,采用快速地气采样装置和ICP-MS分析技术对大深度隐伏多金属矿进行地气测量试验.结果表明,矿体上方Zn、Cu地气异常超过背景值3倍以上,Pb、As、Cd、Bi、Co、Cs、Mo、Rb等也呈现显著异常,证实采用地气测量探测埋深超过800 m的大深度隐伏矿体是完全可行的.     

Study of Carbon‐Bearing Particles in Ascending Geogas Flows in the Dongshengmiao Polymetallic Pyrite Deposit,Inner Mongolia,China

Samples of ascending geogas flow particles were collected on to SiN grids directly in the Quaternary sediments overlying the Dongshengmiao polymetallic pyrite deposit, China. Corresponding soil samples were collected in the surface of Dongshengmiao district at the same time. After pretreatment, these SiN grid samples were analyzed by transmission electron microscopy. The tests focused on the characteristics of particles including size, shape, chemical composition, structure and association. The results show that there are numerous carbon‐bearing particles in particulate samples of the ascending geogas flow. The particles contain organic matter, carbonate or carbonate mixed with other minerals. These carbon‐bearing particles generally contain metallic elements like Fe/Zn/Au/Cu/Pb. However, all of the soil particles do not contain elemental C and only consist of common elements (O, Na, Mg, Al, Si, Ca, Ti) just like the composition of earth crust. Through a comparison between the particles from different sources, the carbon‐bearing particles were found to come only from the deep earth and carried useful information about concealed deposits as they pass through the deep‐seated orebodies. Given the influences of organic matter on mineralization, the carbon‐bearing particle may provide information on the deposit genesis. Combining the use of geogas particle for prospecting with characteristics of large depth, and the carbon‐bearing materials' close spatial and genetic relationship with orebodies, we propose a new prospecting method based on the characteristics of carbon‐bearing particles, including morphology, size, chemical component and ultra‐microstructure. This approach could be applied to the exploration of deposits deep in the earth and abundant in carbon‐bearing matter. This approach can provide efficient and effective deposit exploration.     

油气田上地气物质迁移机制研究

将地气测量技术应用于油气田勘查及评价工作中,地气测量反映出４０００多ｍ的深部构造形成的弱异常,地气异常间接批示了该地区的含气性。地气物质迁移机理研究结果表明,采样器上沉积的物质是以纳米级微粒及其集合体形式存在的。这些纳米级微粒由于具有一系列物理和化学特性,使得它可以与地壳中上升气流的气体相吸咐,随着垂向迁移的气体而上升。不断产生的纳米级微粒被上升气流带到地表,从而在地表形成地气异常。     

Geogas transport in fractured hard rock – Correlations with mining seismicity at 3.54 km depth, TauTona gold mine, South Africa

An on-site gas monitoring study has been conducted in the framework of an earthquake laboratory (The International NELSAM–DAFGAS projects) at the TauTona gold mine, South Africa. Five boreholes up to 60 m long were drilled at 3.54 km depth into the highly fractured Pretorius Fault Zone and instruments for chemical and seismic monitoring installed therein. Over the span of 4 years sensitive gas monitoring devices were continuously improved to enable the direct observation of geogas concentration variations in the DAFGAS borehole. The major gas concentrations are constant and air-like with about 78% N₂, 21% O₂, 1% Ar. The geogas components CO₂, CH₄, He and H₂ show the most interesting trends and variations on the minute-by-minute basis and significantly correlate with seismic data, while the ²²²Rn activity remains constant. Time series and cross correlation analysis allow the identification of different gas components (geogas and tunnel air) and the identification of two processes influencing the borehole gas composition: (1) pumping-induced tunnel air breakthrough through networks of initially water-saturated fault fractures; and (2) seismicity induced permeability enhancement of fault fractures to above ∼5 × 10^-10 m². The current set-up of the gas monitoring system is sensitive enough to quantify the resulting geogas transport during periods of intense blasting activities (including recorded blasts with seismic moment ?1 × 10⁹ Nm, located within 1000 m of the cubby) and, it is suggested, also during induced earthquakes, a final goal of the project.     

滇东北永胜得铜矿床地气微粒特征

为了研究地气微粒特征在探测隐伏矿体中的指示意义,采用地气静态测量法采集滇东北永胜得铜矿区隐伏矿体上方地气纳米微粒,通过高分辨的透射电子显微镜和能谱,对所采集的样品微粒进行形貌分析和元素种类、含量测定后,发现微粒中元素组合特征随着矿体或矿化蚀变带的存在与否出现相应的变化。用地气测量法原理可以较好地解释这一现象,即由脱气作用形成的地气流在从地球深部垂直向上迁移过程中,穿过地质体,吸附具有特征性的微粒并携带至地表,引起相应的元素种类差异和含量异常。这意味着结合这些微粒元素组合特征和地质背景,可以较直接地判断隐伏矿体的有关特点,为找矿工作提供帮助。     

地气场信息的地质学意义

以我国南岭矿集区的两个具有典型意义的区域:湖南黄沙坪和广西大厂,开展了地气场研究,目的是寻找地气场与矿体的关联规律.通过系统分析,研究了矿致地气异常的特征,结果表明,通过地气异常中成分比例的统计,可以判定隐伏矿体是什么成分的矿体;地气异常的元素组合中,可以提取围岩和岩浆活动的一些信息.     

Lithogeochemistry of Carlin-type gold mineralization in the Gold Bar district, Battle Mountain-Eureka trend, Nevada

The Gold Bar district contains five Carlin-type gold deposits and four resources for a combined gold endowment of 1.6 M oz [50 t]. The gold deposits are hosted in Devonian carbonate rocks below parautochthonous and allochthonous Paleozoic siliciclastic rocks emplaced during the Early Mississippian Antler orogeny. The district is in the Battle Mountain-Eureka trend, a long-lived structural feature that localized intrusions and ore deposits of different types and ages.The whole-rock geochemistry of four different mineralized and unmineralized Devonian carbonate rock units (two favorable and two unfavorable) were determined and interpreted in the context of the regional geology. A combination of basic statistics, R-mode factor analysis, isocon plots, and alteration diagrams were utilized to (1) identify favorable geochemical attributes of the host rocks, (2) characterize alteration and associated element enrichments and depletions, and (3) identify the mechanism of gold precipitation. This approach also led to the recognition of other types of alteration and mineralization in host rocks previously thought to be solely affected by Carlin-type mineralization.Unit 2 of the Upper Member of the Denay Formation, with the highest Al₂O₃, Fe₂O₃ and SiO₂ contents and the lowest CaO content, is the most favorable host rock. Based on the high regression coefficients of data arrays on X–Y plots that project toward the origin, Al₂O₃ and TiO₂ were immobile and K₂O and Fe₂O₃ were relatively immobile during alteration and mineralization. Specific element associations identified by factor analysis are also prominent on isocon diagrams that compare the composition of fresh and altered equivalents of the same rock units. The most prominent associations are: Au, As, Sb, SiO₂, Tl, –CaO and –LOI, the main gold mineralizing event and related silicification and decalcification; Cd, Zn, Ag, P, Ni and Tl, an early base metal event; and MgO, early dolomitization. Alteration diagrams, consisting of X–Y plots of SiO₂/Al₂O₃, K₂O/Al₂O₃, CO₂/Al₂O₃, [S/Al₂O₃]/[Fe₂O₃/Al₂O₃], provide evidence for progressive silicification, decarbonation (decalcification and dedolomitization), argillization (illite), and sulfidation as a function of gold mineralization. The latter process is identified as the principal mechanism of gold precipitation.The lithogeochemistry of the ores in the Gold Bar district is typical of that documented in classic Carlin-type gold deposits in the region, but the size of the deposits and the intensity of alteration and mineralization are less. The presence of other types of mineralization in the Gold Bar district is also common to most of the other Carlin-type districts located in major mineral belts. The approach used in this study is well suited to the interpretation of multi-element geochemical data from other study areas with superimposed alteration and mineralization.     

安徽沙坪沟斑岩型钼矿床地质特征及综合找矿信息

沙坪沟钼矿位于安徽省金寨县,是在大别山发现的一个特大型隐伏斑岩型钼矿床。文章根据最新的矿床勘查成果,详细分析了矿床成矿地质条件及矿床地质特征,得出以下几点认识:断裂构造不仅是控岩构造,而且也是导矿构造;隐伏花岗斑岩体不仅提供了矿质来源,同时还控制了矿体空间分布、产状及规模。含矿岩体以富硅、富碱、过铝型以及w(K)>w(Na)为特征。岩体与围岩接触带交代蚀变作用强烈,常见的围岩蚀变有硅化、钾长石化、黄铁矿化、绢云母化、绿泥石化、方解石化等。同时提出了该地区综合找矿信息及找矿思路。     

东天山玉峰金矿热液蚀变作用与元素迁移规律

玉峰金矿位于中亚造山带东天山东缘,是近年来新发现的含银高品位金矿床。该矿床目前已探明6个金矿体,均赋存在石英斑岩中。矿区热液蚀变作用发育,与成矿关系最密切的为黄铁绢英岩化和硅化,显示明显的蚀变分带:以石英硫化物脉为中心,黄铁绢英岩化带在其两侧大致对称分布。本文选取矿体上盘和下盘的石英斑岩、黄铁绢英岩进行了全岩的主、微量元素及成矿元素测试,并对其中的长石和绢云母进行电子探针成分分析。测试结果表明,黄铁绢英岩中的Au含量较蚀变前呈指数级增长,Ag、Cu、As等成矿元素大量增加,CaO、Na_2O、P_2O_5、P_2O_5、Sr、Pb、Th、U、Sb等元素显著迁出,而SiO_2、Al_2O_3、TiO_2含量和稀土元素含量变化较小,表现稳定。热液蚀变过程中,石英斑岩中71%～76%的正长石发生绢云母化,导致K_2O大量迁出;而钠长石几乎全部蚀变为绢云母,造成Na_2O大量迁出。热液流体的贡献使得蚀变岩中MgO、Fe_2O_3~T含量成倍增加,并主要富集在绢云母和/或黄铁矿晶格中。综合分析认为,绢英岩化蚀变带,Au、Cu、As和Bi等元素的综合化探异常,低电阻率、高激化率的地球物理特征可以作为玉峰矿区深部和外围找矿的标志。研究区内的石炭纪石英斑岩带,尤其是在构造叠加部位,热液活动使其更有利于矿化富集,是找矿勘探的有利部位。     

地气测量在戈壁覆盖区210金矿的试验

在新疆哈密和甘肃安西县交界地带的金窝子210隐伏金矿上方,运用泡塑捕集器和液态捕集液进行大比例尺地气测量,深入研究地气测量方法在野外的应用。试验结果显示,隐伏金矿体上方出现了较为明显的Au地球化学异常,并伴随Cu、Pb、Fe等成矿伴生元素的地球化学异常,异常与覆盖层厚度、矿体产状、构造等因素相关。地气法捕集的微量物质的稀土配分模式与210金矿矿石样品的稀土配分模式相似,证明了捕集的微量物质来源于深层隐伏矿体,体现了地球化学深穿透方法在戈壁地区隐伏矿产勘查中具有良好的应用前景。     

Nanogeochemistry of hydrothermal magnetite

Magnetite from hydrothermal ore deposits can contain up to tens of thousands of parts per million (ppm) of elements such as Ti, Si, V, Al, Ca, Mg, Na, which tend to either structurally incorporate into growth and sector zones or form mineral micro- to nano-sized particles. Here, we report micro- to nano-structural and chemical data of hydrothermal magnetite from the Los Colorados iron oxide–apatite deposit in Chile, where magnetite displays both types of trace element incorporation. Three generations of magnetites (X–Z) were identified with concentrations of minor and trace elements that vary significantly: SiO₂, from below detection limit (bdl) to 3.1 wt%; Al₂O₃, 0.3–2.3 wt%; CaO, bdl–0.9 wt%; MgO, 0.02–2.5 wt%; TiO₂, 0.1–0.4 wt%; MnO, 0.04–0.2 wt%; Na₂O, bdl–0.4 wt%; and K₂O, bdl–0.4 wt%. An exception is V₂O₃, which is remarkably constant, ranging from 0.3 to 0.4 wt%. Six types of crystalline nanoparticles (NPs) were identified by means of transmission electron microscopy in the trace element-rich zones, which are each a few micrometres wide: (1) diopside, (2) clinoenstatite; (3) amphibole, (4) mica, (5) ulvöspinel, and (6) Ti-rich magnetite. In addition, Al-rich nanodomains, which contain 2–3 wt% of Al, occur within a single crystal of magnetite. The accumulation of NPs in the trace element-rich zones suggest that they form owing to supersaturation from a hydrothermal fluid, followed by entrapment during continuous growth of the magnetite surface. It is also concluded that mineral NPs promote exsolution of new phases from the mineral host, otherwise preserved as structurally bound trace elements. The presence of abundant mineral NPs in magnetite points to a complex incorporation of trace elements during growth, and provides a cautionary note on the interpretation of micron-scale chemical data of magnetite.     

地气测量研究及在东季金矿的试验

用中子活化分析技术及新研制的地气采集装置,在山东省东季金矿上进行了地气探测及异常研究。文中讨论了对于找隐伏金矿,INAA优于PIXE技术。在构造含矿带上方有明显的La、K、Na、Fe、Sc、Au、As、Cr、Sb及Zn等元素的地气异常。在隐伏矿上方有Au、As、Cr、Sb及Zn等元素异常存在。认为地气中这些金属元素的异常是一种良好的地下金矿化的地表直接指示。     

七里山金矿山的岩石地球化学异常评价与找矿

在七里山金矿区开展了面积性岩石地球化学测量,圈定了4个金异常,其中2个是已知矿的反映,另2个是新发现的金异常。同时研究了已知金矿体的岩石、矿石和异常的元素特征,确定了矿床的指示元素以及元素分带序列,由此建立了异常评价指标。并对4个金异常进行了评价,认为2个新发现的金异常均有良好的找矿前景,提交了验证孔位。经4号金异常进行钻孔验证,在深部见到了富的金矿体。此次化探工作证明该金矿还有隐伏矿体存在,也证明利用岩石裂隙地球化学方法在危机矿山寻找隐伏矿是非常有意义的。