山西铝土矿Rb-Sr同位素定年

采用Rb Sr全岩与粘土矿物等时线年龄方法测得山西五台剖面 (RS0 1) ,临县剖面 (RS0 2 )和孝义剖面 (RS0 3)的 3个含矿粘土岩的Rb Sr同位素年龄分别为 :316 .9± 1.2Ma ,87Sr/86Sr为 0 .710 5 4± 14 ;315 .5± 1.3Ma ,87Sr/86Sr为 0 .710 86±18;317.3± 1.1Ma ,87Sr/86Sr为 0 .710 5 0± 14。它们代表了铝土矿和含矿系列成矿的同位素年龄 ,相当于晚石炭世早期     

皖东侵入岩矿物Rb-Sr和Ar-Ar年代学及其与氧同位素平衡之间的关系

为探讨花岗质岩石中矿物O同位素平衡与Rb Sr矿物等时线年龄有效性之间的关系 ,测定了皖东屯仓与横山两个石英二长岩体中单矿物的Rb Sr和O同位素组成以及角闪石和黑云母的Ar Ar年龄。屯仓岩体的石英 -角闪石对温度为 5 4 5± 2 5℃ ,石英 -黑云母对温度为 4 6 0± 2 0℃ ,石英 -斜长石对温度 385± 4 0℃。横山岩体的石英 -角闪石对温度为 5 30± 2 5℃ ,石英 -黑云母对温度为 390± 15℃和石英 -斜长石对温度 2 85± 35℃。反映封闭体系中矿物在冷却过程中的退化交换再平衡。矿物间的氧同位素平衡对应于有地质意义的Rb Sr矿物等时线年龄。屯仓岩体的全岩 -角闪石 -斜长石Rb Sr等时线年龄 (12 8.4± 4 .7Ma)与角闪石的Ar Ar年龄 (12 5 .5 1± 0 .5 5Ma)在误差范围内一致 ,全岩 -角闪石 -斜长石 -黑云母Rb Sr等时线年龄 (12 0 .3± 2 .6Ma)与黑云母的Ar Ar年龄 (118.0± 0 .1Ma)一致。横山岩体的全岩 -角闪石 -斜长石Rb Sr矿物等时线年龄 (10 8± 15Ma)比角闪石的Ar Ar年龄 (12 5 .7± 1.8Ma)低 ,全岩 -角闪石 -斜长石 -黑云母Rb Sr等时线年龄 (118.6± 1.2Ma)小于黑云母的Ar Ar年龄 (12 0 .0± 0 .2Ma)。Rb Sr等时线年龄小于Ar Ar年龄是由于长石的蚀变引起的。大的等时线误差是由于Rb/Sr比值变化范围太小     

金川铜镍矿床年龄和源区同位素地球化学特征

本文报道了金川铜镍硫化物矿床 Sm- Nd、Rb- Sr、Re- Os同位素年龄测定结果 ,讨论了矿床物质源区。金川铜镍矿床 Re- Os年龄为 10 4 3± 2 8(2 σ) Ma,IOs=0 .15 0 3± 5 0 (2 σ) ;Sm- Nd等时年龄约 0 .97± 0 .31(2 σ)Ga,INd=0 .5 110 6± 2 8(2 σ) ;Rb- Sr等时年龄约 819Ma,ISr=0 .7118。矿床物质来自富集地幔源区。矿床形成可能与Rodinia超大陆的形成和裂解过程有关     

苏北踢球山榴辉岩演化的同位素年代学证据

采用Sm Nd同位素定年方法 ,测得江苏北部新沂地区踢球山三个榴辉岩岩体时代为 :2 2 1.6± 8.4Ma ,2 13.6± 9.2Ma和 2 16 .6± 8.1Ma;εNd(t)分别为 - 2 .9,- 2 .9和 - 3.0。采用Rb Sr定年方法得到其中一个榴辉岩的年龄为 2 0 1± 2 1Ma ;87Sr/ 86Sr =0 .70 5 35± 37。Sm Md年龄被看作为踢球山超高压变质之后板块折返过程中的高压榴辉岩相重结晶阶段年龄。Rb Sr年龄反映了踢球山榴辉岩体的板块折返过程中的角闪岩相退变质阶段开始年龄。为中朝板块与扬子板块碰撞时代主要发生在晚三叠世的观点提供了依据     

内蒙古锡林格勒杂岩的地球化学研究:从Rodinia聚合到古亚洲洋闭合后碰撞造山的历史记录

内蒙古东部出露的锡林格勒杂岩主要由中元古代原岩为火成岩的黑云母片麻岩和斜长角闪岩透镜体组成。片麻岩显示轻稀土元素富集的中等分异特征 ,具明显的Eu负异常 ,其不相容元素特征与平均地壳类似但相对亏损Ba和Sr。斜长角闪岩构成一条Sm -Nd等时线 ,其年龄值为12 0 2± 6 5Ma ,εNd(1.2 0Ga)值为 6 .8。角闪岩的亏损地幔模式年龄 (tDM,1.2 6～ 1.32Ga)与其Sm -Nd同位素等时线年龄接近。角闪岩的Rb -Sr同位素等时线年龄为 393± 14Ma ,其87Sr/ 86 Sr初始比值为 0 .70 379± 0 .0 0 0 0 7,此Rb -Sr等时线年龄与本区出露的篮片岩Ar-Ar年龄 (～ 383Ma)一致 ,记录了中亚造山带东南部洋壳俯冲结束后由大陆碰撞造山引起的变质作用事件。黑云母片麻岩的Rb -Sr同位素等时线年龄为 2 79.5± 6 .4Ma ,87Sr/ 86 Sr初始比值为 0 .70 85 1± 0 .0 0 0 10 ,此Rb -Sr等时线年龄与本区广泛分布的早二叠世火山岩的Rb -Sr等时线年龄 (～ 2 77± 15Ma)一致 ,因此可能是由大规模岩浆活动诱发的变质作用的记录。锡林格勒杂岩因此不仅记录了Rodinia超大陆聚合的地质事件 ,并且通过对比研究本地区蛇绿岩和晚古生代岩浆岩的演化历史 ,可以恢复从Ro dinia超大陆聚合 (～ 1.2 0Ga)到古亚洲洋关闭 (～ 4 30Ma)、大陆碰撞造山 (～ 39     

胶西北丛家岩体岩石成因探讨——岩石地球化学、年代学和Sr—Nd同位素的证据

胶东地区大规模金成矿作用与中生代郭家岭期岩浆活动关系紧密,但针对胶东郭家岭期岩浆岩体的成因仍存在不同认识。本文选择焦家金矿带北段与金矿具有时空关系的郭家岭期丛家岩体作为研究对象,开展系统岩相学、地球化学、LA- MC- ICP- MS 锆石U- Pb年代学及Sr—Nd同位素研究。丛家岩体花岗岩的 Na2O/K2O分别为0. 69～1. 23,Na2O+K2O值为7. 29%～9. 58%,A/CNK值为1. 39～1. 51,为高钾钙碱性系列过铝质花岗岩;丛家岩体具有轻稀土富集、重稀土亏损、负铕异常（0. 41～0. 68）、大离子亲石元素Ba、Sr等富集、 Nb、Ta、Ti等高场强元素亏损、以及高Sr/Y值（81. 59～235. 5）等岩石地球化学特征;丛家岩体锆石LA- MC- ICP- MS的U- Pb年龄为126. 1±0. 3 Ma,可以代表丛家岩体结晶年龄;岩体n(87Sr)/n(86Sr) 值为0. 711463,其低于地壳的平均值（0. 7170）,高于地幔的平均值（0. 7090）,表明其有幔源物质的参与;\[n(87Sr)/n(86Sr)\]i 为0. 711117, Nd (t)的值为-17. 14,亏损地幔模式年龄( TDM2 ) 为3396 Ma。综合分析成因为幔源基性岩浆与下地壳重熔中酸性岩浆发生混合而成,并在上侵过程中受到玲珑期花岗岩的同化混染,是典型幔源物质直接参与混合的壳幔混合成因的花岗岩。     

胶东地区破碎带蚀变岩型金矿时代的测定及其地质意义

通过对胶东半岛西北部超大型破碎带蚀变岩型金矿 -新城金矿的强烈热液交代成因黄铁绢英岩 Rb- Sr等时线法测年 ,获得 116 .6± 5 .3Ma成矿年龄。结合本区焦家、仓上等大型 -超大型金矿蚀变矿物、石英流体包裹体的 Rb- Sr等时线年龄、K- Ar年龄 (10 5± 7Ma;10 6± 2 Ma;113.5± 0 .6 Ma)等前人成果 ,确定胶东半岛西北部破碎带蚀变岩型金矿成矿时代主要集中在 10 0～ 117Ma。与围岩花岗岩、花岗闪长岩的成岩年龄 (16 0～ 15 0 Ma;130～ 12 6 Ma)存在着近 10 Ma的时差 ,并根据(87Sr/ 86 Sr) i比值以及已有的 C、H、O稳定同位素资料表明 ,即使成矿物质部分来源于围岩花岗岩类 ,但成矿作用与岩浆活动无明显的成因关系 ,而是深部循环的大气降水或幔源 C- H - O流体参与成矿作用的结果     

青藏高原唐古拉山中新生代花岗岩锆石U-Pb年龄、地球化学特征及其大陆动力学意义

应用单颗粒锆石 U - Pb法 ,对出露于羌塘地体中央隆起带唐古拉山北坡的花岗岩体进行侵位年代测定 ,结果表明它们是中生代末至新生代早期多次岩浆脉动、涌动上侵定位的产物。其中龙亚拉花岗岩体 (6 9.8± 2 .0Ma)、木乃花岗岩体 (6 7.1± 2 .0 Ma)是印 -亚板块早期碰撞的产物 ;赛多铺岗日花岗岩体 (40 .6± 3.1Ma)为印 -亚板块主碰撞期花岗岩。岩石类型主要包括辉石石英二长岩、二长花岗岩和钾长花岗岩 ,初始锶同位素比值 (87Sr/86 Sr)为 0 .70 6 0 39～ 0 .714 0 6 9。研究表明 ,中生代末至新生代花岗岩浆均起源于壳幔混熔 ,属同碰撞—晚造山期的壳幔型花岗岩。详细的单颗粒锆石 U - Pb同位素定年为研究青藏高原的形成演化与地球动力学过程提供了重要的依据。     

白云鄂博矿床白云岩的Sm—Nd、Rb—Sr同位素体系

白云鄂博矿床的年龄和成因长期争论.本文报道了白云鄂博矿床白云岩及其组成矿物的Sm-Nd、Rb-Sr同位素分析结果.采自该矿床主、东矿等地的15个白云岩样品的Sm-Nd同位素分析结果呈现一条等时线,等时年龄1273±100(2σ)Ma,INd=0.510919士36(2d),MSWD1.01.全岩Rb-Sr同位素分析结果分散,不构成等时线.87Rb/86Sr0～2.092×100-2,87Sr/86Sr0.70341～0.70541.白云岩矿物的Sm-Nd同位素分析结果给予了与全岩类似的Sm-Nd等时年龄,t=1250士210(2σ)Ma,1Nd=0.510914±77(2σ),MSWD 0.56.白云鄂博矿床可能是中元古代末期大离子亲石微量元素略为富集地幔源区部分熔融岩浆活动产物.     

西秦岭南亚带层控金-硒矿床的赋矿地层年代与成矿时代

西秦岭南亚带层控金硒矿床的赋矿地层为太阳顶群 ,为一套主要由炭质硅岩和炭质板岩组成的硅岩建造。对于太阳顶群的时代 ,至今仍众说纷纭 ,莫衷一是 ,大多数人认为属晚寒武世—奥陶纪 ,也有认为属晚震旦—早寒武世。作者通过对古杯类化石的鉴定以及Rb Sr、Sm Nd同位素等时线年龄测定后认为 ,赋矿的太阳顶群时代应属早寒武世 ,而非晚寒武世—奥陶纪 ,更不可能为晚震旦世。对金硒矿床中 2个成矿阶段石英样品进行40 Ar/ 3 9Ar快中子活化测定后获得马鞍型谱线特征。其中坪年龄 (71 .4 5± 0 .5 5 )～ (80 .0 5± 0 .6 5 )Ma、最小视年龄 (70 .2 4± 1 .93)～ (78.5 9± 2 .85 )Ma和等时线年龄 (6 9.4 5± 0 .38)～ (81 .6 1± 0 .5 5 )Ma均十分接近 ,说明所测 2件石英样品的40 Ar/ 3 9Ar年龄真实可靠 ,表明太阳顶群中层控金硒矿床的成矿时间主要发生于燕山运动晚期     

Wavelength-dispersive X-ray fluorescence spectrometric determination of Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites

Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours.     

Isotopic systematics of He,Ar, S,Cu, Ni,Re, Os,Pb, U,Sm, Nd,Rb, Sr,Lu, and Hf in the rocks and ores of the Norilsk deposits

This paper reports the first results of a study of 11 isotope systems (³He/⁴He, ⁴⁰Ar/³⁶Ar, ³⁴S/³²S, ⁶⁵Cu/⁶³Cu, ⁶²Ni/⁶⁰Ni, ⁸⁷Sr/⁸⁶Sr, ¹⁴³Nd/¹⁴⁴Nd, ^206–208Pb/²⁰⁴Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others.     

硅酸盐类样品中硅、铁、铝、钛、锰、钙、镁、钾、钠和磷的x射线荧光光谱测定

本文拟定了一种以熔融法制备样片,用X射线荧光光谱测定硅酸盐类样品中Si、Fe、Al、Tj、Mn、Ca、Mg、K、Na、P等元素的分析方法。在对不同靶材X光管和分光晶体实验对比的基础上,选择了最佳的测量条件。该法具有快速、准确,测量范围广,检测限低,价格便宜等优点。经过近百个各种类型标样或管理样品的分析对比表明,本法不仅适用于硅酸盐类岩石样品的分析,还适用于铁矿、铝土矿、碳酸盐类岩矿样品以及水泥、耐火材料等样品的分析。     

高压微波消解法测定醋酸纤维过滤器采集的微尘粒子中的砷镉钴铬铜铁锰镍铅钒锌

最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提     

硅酸盐中铁、锰、钛、钙、钾、磷、硅、铝、镁、钠、锶、铷、钡的X-射线荧光光谱定量测定

本文介绍样品经四硼酸锂熔融制成玻璃小饼。采用Lachance模式和理论a系数来校正元素间的效应,由3080E型X-射线荧光谱仪和DF-350B数据处理系统完成硅酸盐中十三个项目的测定。     

Viscous, cohesive, non-Newtonian, depositing, radial slurry flow

Mining induced subsidence can significantly affect mining costs where major surface facilities and natural environment need to be protected. Overburden grout injection is a technology used to control coal mine subsidence by injecting the mine waste material extracted from the coal back into the inter-burden rock during longwall mining. The flowing slurry is here categorised as a nonlinear viscous cohesive (Bingham plastic) fluid. During longwall mining the grout slurry is pumped into the separated beds of the rock mass through a central vertical borehole, which is drilled deep into the inter-burden rock strata above the coal seam. However, a blockage can occur in the injection system when the slurry velocity falls below a certain critical threshold velocity, indicating a material phase change from cohesive-viscous to cohesive-frictional. In situ field injection tests through boreholes have been simulated at a smaller scale at the CSIRO laboratory in Brisbane by pumping the slurry through a radial disk (gap = 4 mm) from its centre. Laboratory experiments indicate a general, nonlinear, cohesive, viscous, frictional model for shear behaviour of the slurry, in which the material shear parameters are functions of the disk radial distance. Complete dimensional and dimensionless analytical solutions have been developed based on an approach related to Bingham–Herschel–Bulkley fluid mechanics. The derived formulae include relations for minimum pump pressure, local pressure and pressure gradient, wall shear stress, volume rate, velocity and velocity gradient. The theoretical results match the experimental measurements. The experiments covered slurries with maximum particle sizes of 0.5 to 2 mm with about 50% being larger than 100 µm. The viscosities at the various solids concentrations were measured with a standard torsion viscometer. This study differs from the previous research in several distinct aspects, namely, consideration of the variable shear parameters rather than fixed values, inclusion of total nonlinear behaviour, and implementation of a friction function to mimic behaviour of the deposited and consolidating stiff slurry, which can cause a significant pressure rise as a result of the increased shear resistance.     

Bellechester,Minnesota, USA,lagoon collapses

Bellechester, Minnesota, is a small community of approximately 155 residents located on the county line between Goodhue and Wabasha counties in southeast Minnesota's karst region. Bellechester is served by a 21-year-old wastewater treatment facility (WWTF) consisting of three waste-stabilization ponds. On 28 April 1992 six sinkholes were discovered to have drained cell 2 of the WWTF resulting in the loss of approximately 8.7×10⁶ 1 of partially treated effluent and about 600 m³ of soil into previously undetected subsurface voids of unknown dimensions. In the week following the collapse, approximately 200 water wells located within a 5-km radius of the WWTF were sampled in an after-the-fact, emergency sampling program. Twelve samples with elevated fecal coliform levels, 18 samples with nitrate-nitrogen greater than the 10 mg/1 standard, and no samples with elevated chlorides were found. However, the elevated levels could not be unambiguously attributed to the WWTF collapse. This is the third WWTF to fail by sinkhole collapse in southeast Minnesota since 1974. All three collapsed lagoons have been located in similar geomorphic and stratigraphic settings. However, at least two lagoons have collapsed in the adjacent area in northeast Iowa, and these lagoons are located at different stratigraphic positions. Twenty-two WWTFs constructed in southeast Minnesota's karst region in the last 25 years have been identified as subject to potential sinkhole collapse. An unknown but significant number of manure storage lagoons, flood control structures, etc., have also been constructed in the karst region and are at risk. Public agencies are beginning to develop plans to deal with the risk associated with existing and future waste lagoons in this environment. The critical hydrogeologic parameters that can be used to prioritize the risk of collapse at existing facilities include: (1) the lithology of the first bedrock beneath each lagoon, (2) the thickness of surficial materials between the lagoon and the bedrock surface, (3) the presence and construction of liners (seepage rate), and (4) the proximity to existing sinkholes.     

岩石密度和超高压岩石折返速率

在常温常压条件下对中国大陆科学钻CCSD主孔100-3000米岩心样品进行了密度测量,建立了密度连续剖面,并界定了不同超高压岩石的密度值。通过对比高温高压物性实验资料,岩石密度随着退变程度增强而降低,榴辉岩密度变化序列为3.52g/cm3→3.49g/cm3→3.07g/cm3→2.93g/cm3。超高压长英质岩石密度变化序列为3.00g/cm→2.80g/cm3→2.65g/cm3。上述实验资料是讨论不同折返阶段岩石所受浮力的基础,为研究折返速率大小提供了基本参数。本文通过折返板块运动平衡时,上浮力与粘滞力平衡这一关系式,定量研究了大陆俯冲板块的折返速率,认为密度差产生上浮力从而引起折返,温度对板块折返速率的影响最为显著;密度差大小、折返角度、折返板块大小对折返速率也有直接的影响。定量模拟分析表明,在温度高于850℃时,板块的折返速率可以超过100mm/a;当温度降至700℃时,折返速率则低于1.5mm/a。作者认为在折返早期,温度较高,板块快速折返至60-70km榴辉岩相深度;随着传导散热,温度降低,板块以较慢的速率折返至中下地壳。折返速率的估算表明,浮力是板块折返第一阶段(从>100km深部折返至<40km的中下地壳)的主要驱动力。     

Mercury,arsenic, antimony,and selenium contents of sediment from the Kuskokwim River,Bethel, Alaska,USA

The Kuskokwim River at Bethel, Alaska, drains a major mercury-antimony metallogenic province in its upper reaches and tributaries. Bethel (population 4000) is situated on the Kuskokwim floodplain and also draws its water supply from wells located in river-deposited sediment. A boring through overbank and floodplain sediment has provided material to establish a baseline datum for sediment-hosted heavy metals. Mercury (total), arsenic, antimony, and selenium contents were determined; aluminum was also determined and used as normalizing factor. The contents of the heavy metals were relatively constant with depth and do not reflect any potential enrichment from upstream contaminant sources.