望天鹅火山岩石地球化学特征及其成因

东北吉林望天鹅新生代火山岩（7．04—1．86Ma）主要由玄武粗安岩和碱性流纹岩组成。玄武粗安岩的SiO2介于49．38％-53．31％之间;K2O＋Na2O为4．27％-7．72％;∑REE为163．69×10^-6-258．55×10^-6,Eu异常不明显,δEu为0．72～1．17;碱性流纹岩具高SiO2（70．39％～71．49％）含量,高碱（K2O＋Na2O为9．28％～9．49％）,高稀土总量（∑REE介于309．30×10^-6～465．03×10^-6之间）,明显的Eu负异常,3Eu为0．52～0．71。碱性流纹岩的微量元素含量较玄武粗安岩高,且具有明显的Sr、P、Ti负异常。望天鹅火山岩的^87Sr／^86Sr比值在0．705156-0．709029之间,而^144Nd／^143Nd比值变化较小,介于0．512295～0．512602之间;放射性成因Pb同位素变化范围也较小,^206Ph／^204Pb为17．254～18．090,^207Ph／^204Pb为15．460～15．507,^208Pb／^204Ph为37．278—38．048。综合分析火山岩的主量元素、微量元素和Sr-Nd—Pb同位素特点,初步认为望天鹅火山的玄武粗安岩和碱性流纹岩具有相同的地幔源区。玄武粗安岩起源于微弱富集上地幔,在上升过程中结晶分异形成了碱性流纹岩。     

辽西凌源地区义县组火山岩锆石U—Pb年代学和地球化学特征

对辽西凌源地区义县组的1件流纹岩样品进行锆石U—Pb年代学研究,获得的年龄为（124．4±1．4）Ma,与前人对辽西北票、义县、凌源等地区通过K—Ar、Ar—Ar、U—Pb等定年方法获得的义县组年龄基本一致,时代为早白垩世。7件典型火山岩样品的地球化学研究结果表明,该火山岩的SiO2=65．6％-73．4％,MgO=0．35％～1．23％,Mg^#=16～41,Al2O3=13．40％～16．79％,Na2O=3．54％-4．26％。Sr=（445～774）×10^-6,Yb=（0．51-0．97）×10^-6,V=（7～14）×10^-6,Sr／Y=49-66,LaN／YbN=33-48,高Sr和Sr／Y比值,低Y和Yb,轻重稀土元素分异明显,显示出埃达克岩的地球化学特征,但其Mg^#较低。它们可能是加厚的基性下地壳部分熔融的产物。     

青藏高原北羌塘盆地上三叠统那底岗日组火山岩 的地球化学特征及其意义

北羌塘盆地南缘的晚三叠世那底岗日组火山岩主要由英安岩、流纹岩、凝灰岩等组成。其主量元素具有高SiO2（66．58%-80．90％）、低TiO2（0．12％-0．42％）的特征,属钙碱性系列（σ平均为1．245）;微量元素表现为大离子亲石元素K、Rb、Ba及不相容元素Th的高度富集和高场强元素Nb、Ta、Ti的亏损;稀土元素（La／Yb）N〉10,Eu亏损较明显（δEu=0．53-43．88）,配分曲线右倾、较陡;Pb、Nd、Sr同位素组成为（^206Nd／^204Nb）T=18．531-18．838、（^207Pb／^204Pb）T=15．749-15．859、（^308Pb／。^204）T=37．138-37．917、（^87Sr／^86Sr）i=0．70852-0．71086、（^143Nd／^144Nd）。=0．511779-43．511896、εNa（t=208Ma）=-9．3--11．6。上述岩石地球化学特征表明,那底岗日和石水河的那底岗日组火山岩的岩浆源区为上地壳;同时利用同位素地球化学数据证明了北羌塘地块归属扬子陆块群的论断,即北羌塘盆地存在元古宙结晶基底的信息。     

青藏高原北羌塘盆地上三叠统那底岗日组火山岩的地球化学特征及其意义

北羌塘盆地南缘的晚三叠世那底岗日组火山岩主要由英安岩、流纹岩、凝灰岩等组成。其主量元素具有高SiO2（66．58%-80．90％）、低TiO2（0．12％-0．42％）的特征,属钙碱性系列（σ平均为1．245）;微量元素表现为大离子亲石元素K、Rb、Ba及不相容元素Th的高度富集和高场强元素Nb、Ta、Ti的亏损;稀土元素（La／Yb）N〉10,Eu亏损较明显（δEu=0．53-43．88）,配分曲线右倾、较陡;Pb、Nd、Sr同位素组成为（^206Nd／^204Nb）T=18．531-18．838、（^207Pb／^204Pb）T=15．749-15．859、（^308Pb／。^204）T=37．138-37．917、（^87Sr／^86Sr）i=0．70852-0．71086、（^143Nd／^144Nd）。=0．511779-43．511896、εNa（t=208Ma）=-9．3--11．6。上述岩石地球化学特征表明,那底岗日和石水河的那底岗日组火山岩的岩浆源区为上地壳;同时利用同位素地球化学数据证明了北羌塘地块归属扬子陆块群的论断,即北羌塘盆地存在元古宙结晶基底的信息。     

赣中南新元古代潭头群变质沉积岩物源及构造背景

赣中南一带广泛出露前震旦纪新元古代潭头群变质沉积岩,地层中火山岩较发育,属火山-沉积碎屑岩组合。其砂质岩石具有中等含量的SiO2（64．81％～71．77％,平均为68．30％）,较低的FeOt＋MgO（4．08％～6．99％,平均为5．74％）和较高的K2O／Na2O（0．75～3．33,平均为1．64）及Al2O3／TiO2（26．02～43．47,平均为31．73）。稀土总量较高（∑REE为158．44×10^-6～293．36×10^-6。平均为237．98×10^-6）,轻稀土明显富集。所有样品的稀土分布模式相似,明显向右倾斜,具有中等程度的Eu异常（δEu为0．42～0．61,平均为0．48）。微量元素平均含量与上地壳平均组分相当。地球化学特征表明,赣中南新元古代潭头群变质沉积岩可能来源于古-中元古代地层。结合变质岩的沉积环境及其火山岩特征,研究认为潭头群的构造背景属岛弧环境,可能与新元古代华夏陆块和扬子陆块的俯冲碰撞有关。     

辽西北票早侏罗世兴隆沟组英安岩的地球化学特征

辽西北票早侏罗世兴隆沟组英安岩具有埃达克岩的地球化学特征。它们具有较高的SiO2（≥63．93％）、Al2O3（≥15．40％）、Na2O（≥3．65％）和MgO（≥2．32％，Mg^#=0．48～0．61）含量，较高的Sr（〉463μg／g）、Cr（〉119μg／g）、Ni（〉75μg／g）含量，较低的Yb（〈1．70μg／g）、Y（〈17μg/g）含量，高的La／Yb（〉18）、Sr／Y（〉34）值和低Rb／Sr（≤0．31）比值，稀土元素强烈分馏，弱的负铕异常（Eu／Eu^＋=0．80～0．87）．它们的Nd同位素（^143Nd/^144Nd=0．512414～0．512502．εND（t）=-2．10～-0．38，TDM：0．89～1．02Ga），Sr同位素（^87Sr／^86Sr=0．7073～0．7075，8Sr（t）=11．16～13．78）和Pb同位素（^206Pb／^204Pb=18．28～18．40，^207Pb／^204Pb=15．42～15．53，^208Ph／^204Pb=38．08～38．27）组成与华北陆块古老的岩石圈地幔及其中的中晚侏罗世和早白垩世火山岩不同。这表明兴隆沟组英安岩可能是古亚洲洋壳残片部分熔融形成的，熔体在上升过程中与地幔楔发生过强烈的混染作用。据此，推测古亚洲洋曾向华北陆块发生过俯冲作用。     

南天山南缘早二叠世酸性火山岩的地球化学、同位素年代学及其构造意义

南天山南缘小提坎里克组酸性火山岩高碱（Na2O＋K2O=6．03％～7．70％）且富钾（K2O／Na2O=2．35,5．03）,铝饱和指数A／CNK=0．89～1．59（平均1．24）,里特曼指数（σ）为1．48,属于过铝质高钾钙碱性火山岩系。轻稀土强烈富集,亏损Ba、Cs、Nb、Ta、Sr等大离子亲石元素,Hf、Zr等高场强元素基本无亏损,具有明显的负铕异常（δEu=0．44～0．66）,总体具有碰撞晚期花岗岩类的地球化学特点。岩石的Nd／Th（1．78—3．50）、Th／U（4．10～9．79）、La/Ta（17．69～35．77）和Nb／Ta（10．48～11．84）比值显示了壳源特征。对火山岩中锆石进行的激光探针等离子体质谱（LA-ICP—MS）U—Pb微区测定获得了289．4±5．5Ma的形成年龄。结合区域构造分析认为,早二叠世初南天山地区处于碰撞晚期冲断造山作用阶段,小提坎里克组火山岩是对南天山造山带南缘碰撞晚期冲断变形和前陆盆地发育的响应。     

新疆阿尔金山地区元古宙超钾质碱性岩的发现

阿尔金山巴什考供附近的超钾质碱性岩,以互层 状产出于斜长角 闪岩中。该超钾质碱性岩的SiO2含量为40.77%～40.98%,K2O + Na2O = 3.68%～6.94 %,K 2O/ Na2O为3.28～7.76,属于超钾质强碱性岩。岩石的稀土元素总量较高,介于70 5.68 ×10 -6～972.34×10-6之间,(La/Yb)n为37.27和43.53,Eu呈轻度负异常(Eu=0. 67～0.75),球粒陨 石标准化配分曲线显示轻稀土高度富集,重稀土低度富集特征,与典型的超钾质碱性岩配分 型式相似。该超钾质碱性岩的发现对研究该区壳幔相互作用及岩石圈演化具有深 远意义。     

胶北晚中生代煌斑岩的岩石地球化学特征及其成因研究

胶北煌斑岩分别采自龙口、烟台和威海地区，包括拉辉煌斑岩、斜闪正煌岩和角闪煌斑岩，煌斑岩K—Ar全岩年龄变化于89．3～169．5Ma，为晚中生代岩浆活动的产物。在岩石化学组成上，SiO2=42．02％～54．95％，以钙碱性系列为主．岩石以富集大离子亲石元素（LILE）（Ba，U，K，Th）和LREE，亏损高场强元素（HFSE）（Nb，Ta和Ti）为特征，Mg^#=33．9～53．9，Eu／Eu^＊=0．71～0．89，^87Sr／^86Sr初始比值0．707642～0．709791，εNd（t）为-17．6～-10．4，^206Pb／^204Pb=37．588～38．431，^207Pb／^204Pb=15．423～15．531，^206Pb／^204Pb=17．204～18．179。表明煌斑岩源自俯冲陆壳（扬子下地壳）在地幔源区发生交代作用时形成的富集型地幔的部分熔融体．考虑到煌斑岩具有大陆边缘弧玄武岩的特征，我们认为煌斑岩在成因上同样与古大洋板块的俯冲作用有关，为碰撞后弧岩浆作用形成的脉岩。     

大兴安岭北段牙克石地区玄武质火山岩的元素、同位素地球化学特征及其地质意义

牙克石地区出露一套早白垩世玄武质火山岩,其SiO2含量为52．81%-53．39％,K2O含量为1．86％-2．87％,岩性为玄武质粗面安山岩。富集大离子亲石元素Rb和Ba,高场强元素Nb和Ta亏损明显,Zr和H阮明显异常,8Eu为0．77-0．82。从同住素的特点看,（^87Sr／^86Sr）,变化于0．704762-0．704941之间,εNd（t）为2．00～2．54;在εNd（t）-（^87Sr／^86Sr）闺解上,样品投影点落入洋岛玄武岩（OIB）和美国盆岭省范围内。^206Pb／^204pb为18．3288-18．4225,^207b／^204Pb为15、4566-15．4893,^208Pb／^204Pb为37．9401-38．0523：在。^207Pb/^24Pb-^206Pb.^204pb和,^208b／^304pb-^306Pb／^204pb图解上．样品投影点都落在亏损洋中脊玄武岩地幔附近。综合考虑本区火山岩的地质、地球化学特点,认为其来源于被俯冲洋壳交代的岩石圈地幔。     

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.     

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     

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.     

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.     

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。     

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。     

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.     

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.     

滇东南花岗岩与锡、银、铜、铅、锌多金属矿床的成因关系

滇东南锡、银、铅、锌多金属矿床主要分布在个旧、白牛厂、都龙3个矿区,而滇东南较大的3个花岗岩体又分别出露在3个矿区或附近.花岗岩体均形成于燕山晚期,岩石化学、矿物成分相似,富含锡、银、铅、锌、钨、铜等成矿元素.矿床主金属元素组合与岩体之间的距离由远而近出现由锡、钨、(铍、铌、钽)→锡、钨、(铁)、铜、铟→锡、铅、锌、银、铟、(锑)有规律的变化.花岗岩浆是成矿物质来源和成矿热源.岩浆侵入初期使上覆地层隆起产生背斜(凹陷部位成向斜);同时使地层产生一系列裂隙、压性断层或层间断裂;岩浆侵入晚期,这些断层再次活动,表现为张性,岩浆产生的含矿热液沿由其活动所造成的断裂迁移、充填、交代、沉淀而形成矿床.