东准噶尔和尔赛斑岩铜矿成岩成矿时代与形成的构造背景

东准噶尔和尔赛铜矿是近年来新发现的斑岩型铜矿,位于野马泉-琼河坝古生代岛弧带东段。成矿岩体为侵位于花岗闪长岩中的花岗闪长斑岩,花岗闪岩中包含有钾长花岗岩体。锆石CAMECA U-Pb测年结果显示,钾长花岗岩年龄为429Ma,并含有405Ma的锆石;花岗闪长岩年龄为411Ma,并含432Ma的碎屑锆石;花岗闪长斑岩主体年龄为410.5Ma。研究区经历了3期岩浆与热液活动,且至少在早志留世就已开始,琼河坝岛弧是开始于早古生代的岛弧。辉钼矿Re-Os等时线年龄为409Ma,与花岗闪长斑岩年龄一致。和尔赛斑岩铜矿的主成岩成矿时代为早泥盆世,年龄约为410Ma。和尔赛铜矿的花岗闪长岩和花岗闪长斑岩具有埃达克岩与岛弧岩浆岩的地球化学特征,包括63.79%～68.86%SiO2、14.91%～17.48%Al2O3、0.68%～2.35%MgO、高Sr(383×10-6～971×10-6)与Sr/Y比值(48.3～111)、低Y(7.92×10-6～9.69×10-6)与Yb(0.76×10-6～0.98×10-6),Ba、U、K、Sr等大离子元素富集,Th、Nb、Ta、Ti等高场强元素亏损,较低的(87Sr/86Sr)i值(0.703852～0.704565)、正的εNd(t)值(6.1～7.4)、与亏损地幔接近的较低的初始铅同位素比值((206Pb/204Pb)i=17.58～17.91,(207Pb/204Pb)i=15.40～15.48,(208Pb/204Pb)i=37.25～37.47)。这些地球化学特征说明其形成于岛弧环境,可能为古俯冲洋壳部分熔融的产物。琼河坝地区以花岗闪长岩和花岗闪长斑岩为代表的岩浆岩带是形成和寻找斑岩铜矿的有利地区。     

内蒙古大苏计斑岩钼矿床花岗质杂岩年代学、地球化学、Hf同位素组成及其地质意义

内蒙古卓资县大苏计斑岩钼矿化与区内花岗质杂岩(石英斑岩、正长花岗斑岩和花岗斑岩)有密切的成因联系。LA-ICP-MS锆石U-Pb定年获得石英斑岩、正长花岗斑岩和花岗斑岩的结晶年龄分别为(234±3)Ma、(225±4)Ma和(220±4)Ma。杂岩体富硅(w(SiO_2)=70.37%~78.84%)、富碱(w(Na_2O+K_2O)=4.52%~8.77%),均属高钾钙碱性系列,普遍具有低的w(Na_2O)(0.15%~2.69%)和高的铝指数(ASI介于1.13~3.35)。稀土元素总量介于48.2×10~(-6)~527.0×10~(-6),石英斑岩稀土元素含量(48.2×10~(-6)~83.1×10~(-6))最低,正长花岗斑岩稀土元素含量(272.1×10~(-6)~527.0×10~(-6))最高,花岗斑岩稀土元素含量为162.5×10~(-6)~236.8×10~(-6);杂岩体δEu介于0.15~0.93之间,(La/Yb)N介于3.0~65.5,自正长花岗斑岩、花岗斑岩到石英斑岩,其Eu负异常逐渐増大,而(La/Yb)N逐渐减小。岩体普遍富集Rb、Th、U、K、Nd、Zr、Hf等,强烈亏损Sr、P、Ti等。正长花岗斑岩具有中等Ba、Ta、Nb亏损。石英斑岩和花岗斑岩均属于高分异花岗岩,而正长花岗斑岩属于I型花岗岩。主量、稀土和微量元素特征表明,杂岩体具有后碰撞或后造山花岗岩特征,形成于后碰撞或后造山环境。杂岩体锆石的Hf同位素显示,3种岩石的εHf(t)值介于-21.1~-8.1,二阶段模式年龄tDM2介于1775~2587 Ma。石英斑岩来自于古元古代地壳物质的部分熔融;正长花岗斑岩来自于古元古代晚期地壳物质的部分熔融;花岗斑岩也主要来自于古元古代地壳物质的部分熔融,但有少量新太古代地壳物质参与。     

豫西银家沟硫铁多金属矿床Re-Os和40Ar-39Ar年龄及其地质意义

河南省银家沟硫铁多金属矿床位于华北克拉通南缘的华熊地块内,是东秦岭地区最大的硫铁多金属矿床,以其硫铁矿储量大及共、伴生元素复杂区别于东秦岭其他以钼为主的矿床.矿化在空间上呈规律性的带状分布,从岩体内向外,依次出现斑岩型钼矿体→斑岩型硫铁矿体→矽卡岩型铁矿体、钼矿体→矽卡岩型硫铁、铜、锌、金矿体→脉型铅、锌、银矿体.选取5件接触带矽卡岩型钼矿体中的辉钼矿样品进行Re-Os同位素定年,获得(142.9±2.1) Ma～(143.7±2.3) Ma的模式年龄,加权平均值为(143.4±0.9) Ma(MSWD=0.071),等时线年龄为(140.0±18.0) Ma(2σ,MSWD=0.095),将(143.4±0.9) Ma认作辉钼矿的结晶年龄,表明银家沟矿床矽卡岩型矿体形成于约143 Ma前;选取1件硅化、绢云母化、黄铁矿化、辉钼矿化钾长花岗斑岩中的绢云母样品定年,获得40Ar-39Ar坪年龄为(143.6±1.4) Ma,相应的39 Ar/36 Ar-40 Ar/39Ar等时线年龄为(143.0±2.0) Ma(MSWD=0.13),将(143.0±2.0)Ma认作绢云母的Ar封闭年龄,表明银家沟矿床斑岩型矿化亦发生在约143Ma前.本次辉钼矿Re-Os和绢云母40Ar-39A定年结果表明,银家沟矽卡岩型和斑岩型矿体均形成于早白垩世初期.银家沟矿床辉钼矿的ω(Re)在38.5×10-6～43.2×10-6之间,成矿物质主要来自由火成物质组成的宽坪群和二郎坪群,成矿与矿区内的钾长花岗斑岩有关.结合前人对东秦岭造山带中生代期间地球动力学背景的研究成果,笔者认为银家沟矿床形成于EW向构造体制向NNE向构造体制大转换阶段,即形成于挤压体制向伸展体制转换的背景.     

广西大瑶山大黎花岗岩体年代学研究及地质意义

大瑶山成矿带大黎花岗岩体主要岩性为花岗闪长斑岩、花岗闪长岩、二长花岗岩和二长花岗斑岩。岩体侵入于寒武系黄洞口组,两个花岗闪长斑岩的LA-ICP-MS锆石U-Pb定年结果为(99.5±1.4)Ma和(102.3±1.5)Ma,为早白垩世的岩浆活动产物。常量元素具有高硅、富碱、富钙的特点,为钙碱性准铝质系列岩石,显示I型花岗岩的特征。稀土元素具有右倾型的配分模式,∑REE为150.63×10-6~192.13×10-6,轻微的负铕异常,δEu值为0.73~0.85。微量元素富集Rb、U、Th、La、Ce等大离子亲石元素(LILE),亏损Nb、Ta、Ti、P等高场强元素(HFS)。大黎花岗岩的初始Sr比值为0.7076~0.7078,~(147)Sm/~(144)Nd值是0.0960~0.1055,(~(143)Nd/~(144)Nd)i值为0.5122~0.5123,εNd(t)值为-5.29~-3.55,模式年龄T1DM为0.98~1.12Ga;矫正后的~(206)Pb/~(204)Pb、~(207)Pb/~(204)Pb、~(208)Pb/~(204)Pb值分别为18.0745~18.2316、15.6241~15.664、38.4129~38.5852;上述Sr-Nd-Pb同位素特征表明大黎岩体的成岩物质来自于上地壳物质的部分熔融。构造环境判别图解中,大黎花岗岩体形成于一种碰撞的构造环境,可能与燕山晚期古太平洋板块的碰撞作用有关系。     

西天山喇嘛苏岩体年代学、地球化学及成矿意义

文中主要对西天山喇嘛苏岩体进行SHRIMP锆石U-Pb年龄、主微量及Sr-Nd-Pb同位素测定,阐明岩体成因及形成构造背景。喇嘛苏岩体主要由石英二长闪长岩、花岗闪长斑岩和英云闪长斑岩组成。其中,石英二长闪长岩形成于(394.8±4.9)Ma,花岗闪长斑岩和英云闪长斑岩形成于(380.9±3.9)Ma,略晚于石英二长闪长岩。岩体具有埃达克质岩的特征,且显示从钙碱性向高钾钙碱性演化的趋势,稀土元素配分曲线显示相对富集轻稀土((La/Yb)N:3.55～15.52)及中等的负或正Eu异常(δEu:0.53～1.12)。岩体具有较高的Sr含量((322～808)×10-6)和较低的Y含量((12.90～18.86)×10-6)。微量元素特征显示岩体富集LILE亏损HFSE,并具有Nb、Ta和Ti负异常。岩体初始Sr-Nd同位素组成为εNd(t)=-4.29～+0.75和ISr=0.706 052～0.708 263,Nd模式年龄为1.03～1.46Ga。花岗闪长斑岩和英云闪长斑岩的铅同位素特征为206Pb/204Pb=18.500～19.044,207Pb/204Pb=15.575～15.626,208Pb/204Pb=38.443～38.864;石英二长闪长岩为206Pb/204Pb=18.694～18.711,207Pb/204Pb=15.622～15.630,208Pb/204Pb=38.648～38.660。所有地球化学特征显示喇嘛苏岩体是俯冲洋壳部分熔融形成的熔体,上升过程中与受俯冲带沉积物交代的地幔楔相互作用,且有少量古老地壳的混染而形成。岩体形成于晚泥盆世准噶尔残余洋盆向伊犁—中天山地块俯冲的大陆弧背景,与该区Cu(Au)矿化有较密切的联系。     

蒙古国查干苏布尔加大型铜-钼矿床地质特征及成因

查干苏布尔加斑岩铜钼矿床位于西伯利亚板块南缘近东西向和北东向深大断裂所夹持的南蒙古构造岩浆带内, 容矿围岩二长花岗斑岩与花岗闪长斑岩主量元素高SiO2(64.69?10?2~73.42?10?2), 高Al2O3 (15.33?10?2~18.35?10?2), 贫MgO(0.13?10?2~0.56?10?2), 微量元素Sr二长花岗斑岩略低(144?10?6~175?10?6), 花岗闪长斑岩表现为高Sr(样品>300?10?6, 476?10?6~720?10?6), 二者均低Y(Y<18?10?6, 2.21?10?6~ 10.20?10?6), 低Yb(Yb<1.9?10?6, 0.30?10?6~1.48?10?6), 高Sr/Y(Sr/Y>20, 21.8~63.52), 稀土元素特征为亏损重稀土, 无明显负铕异常, (87Sr/86Sr)i=0.70154~0.70397, (143Nd/144Nd)i=0.512290~0.512600,εNd(t)为+2.4~+8.5, 二长花岗斑岩和花岗闪长斑岩均具有埃达克质岩特征, 但二长花岗斑岩与花岗闪长斑岩主、微量和稀土元素又存在一定差别, 它们可能是岩浆不同演化阶段的产物。通过年龄测定, 获得辉钼矿Re-Os等时线年龄为(370.0±5.9)Ma, 二长花岗斑岩锆石SHRIMP U-Pb加权平均年龄为(365.7±3.6)Ma, 铜钼矿形成时代与二长花岗斑岩形成时代相近, 均形成于晚泥盆世。铜钼矿床与二长花岗斑岩、花岗闪长斑岩紧密共生, 矿区范围内二长花岗斑岩与花岗闪长斑岩多被蚀变并矿化, 表明二长花岗斑岩、花岗闪长斑岩与铜钼矿化存在密切的时空关系, 为铜钼成矿提供了主要成矿物质和流体来源。     

内蒙古乌奴格吐山斑岩铜钼矿床低Sr-Yb型成矿斑岩地球化学特征及地质意义

内蒙古满洲里乌奴格吐山大型斑岩铜-钼矿床位于大兴安岭北段西侧的满洲里新右旗。成矿岩体类型为二长花岗斑岩,年代学研究表明该斑岩形成于早侏罗世。元素地球化学表明,斑岩呈钙碱性、具高Si、富Al和Na、高A/CNK值,低Ca、Mg和Fe_2O_3~T特征;稀土元素Eu无异常,微量元素表现出富集大离子亲石元素,亏损高场强元素,Sr(16.51×10~(-6)～95.58×10~(-6))和Yb(0.39×10~(-6)～0.82×10~(-6))含量低的特点,总体上成矿斑岩为低Sr低Yb特征的Ⅰ型花岗岩。斑岩初始锶比值为0.70522～0.70690,ε_(Nd)(t)值为0.3～1.0,Pb同位素组成较均匀,其中~(206)Pb/~(204)Pb比值为18.563～18.926,~(207)Pb/~(204)Pb为15.568～15.598,~(208)Pb/~(204)Pb为38.255～38.529。上述地球化学特征反映成矿斑岩岩浆起源于加厚的下地壳底部,来自岩石圈地幔热源诱发下地壳底部发生减压熔融。同时乌奴格吐山这套低Sr低Yb的Ⅰ型花岗斑岩的出现,指示了早侏罗世蒙古-鄂霍次克海闭合、华北板块与西伯利亚板块碰撞后引张的构造环境。通过对乌山斑岩铜矿与全国其它斑岩型铜-钼矿床对比发现,其成矿斑岩地球化学具有许多相似性。结合区域地质和地球化学,我们认为本地区Cu和Mo具有很大的成矿潜力。     

东秦岭钼矿带内碳酸岩脉型钼（铅）矿床地质 地球化学特征、成矿机制及成矿构造背景

东秦岭钼矿带位于华北板块南缘,NW-NWW向的固始―栾川深断裂带控制着钼矿床的空间分布.黄水庵碳酸岩脉型钼(铅)矿床的确定,为本矿带内已有碳酸岩脉型钼(铅)矿床(黄龙铺地区的大石沟、石家湾和桃园等)增添了又一新成员.本矿带不仅钼金属储量居世界已知单个钼矿带之首,而且碳酸岩脉和花岗斑岩两个成矿体系并存,亦是本区钼矿带的一大特色.业已查明,黄水庵和黄龙铺(大石沟)等碳酸岩脉型钼(铅)矿床的δ~(13)C=-5.3‰～-7.0‰,~(87)Sr/~(86)Sr=0.7049～0.7065.同时,方解石富含轻稀土(LREE/HREE=1.8～2.9).辉钼矿以富含Re(平均为110×10~(-6)～244×10~(-6))为特征.基于含矿碳酸岩脉方解石的Sr、Nd、Pb同位素比值(~(87)Sr/~(86)Sr对~(206)Pb/~(204)Pb、~(207)Pb/~(204)Pb对~(206)Pb/~(204)Pb和~(143)Nd/~(144)Nd对~(87)Sr/~(86)Sr)的关系图,我们初步判断本矿带区域陆壳之下可能存在有EMI(富集地幔Ⅰ),这些含矿碳酸岩脉是源于EMI的碱性硅酸盐-碳酸盐熔体-溶液结晶分异的产物,成矿金属Mo、Pb主要来自EMI.根据黄水庵和黄龙铺(大石沟)钼(铅)矿床的成矿年龄(Re-Os年龄分别为209.5 Ma和221 Ma),我们推断,碳酸岩脉型钼(铅)矿床形成于华北和扬子两大板块三叠纪碰撞造山后伸展阶段的晚三叠世时期,而在侏罗纪陆内造山晚期的伸展阶段,形成了晚侏罗-早白垩世的斑岩型和斑岩-矽卡岩型钼矿床(Re-Os年龄介于147～116 Ma).     

西秦岭阳山金矿带花岗斑岩元素及Sr-Nd-Pb同位素地球化学

甘肃阳山金矿带的花岗斑岩脉中含有石榴子石,A/CNK=1.65～3.65,属于强过铝质花岗岩类.花岗斑岩相对富集LILE和LREE,亏损Ba、Sr、Nb、Ta、P、Ti等,配分模式类似于典型同碰撞型花岗岩类;花岗斑岩ΣREE=54.35～124.01×10-6,(La/Yb)N=9.72-27.80,δEu=0.70～0.89,表明其岩浆形成时部分斜长石进入熔体,而非完全残留.花岗斑岩Isr值为0.70806～0.71756,平均0.71107;εNd(t)值变化于-2.9～-5.0,平均-3.4;Nd模式年龄(T2DM)为1.24～1.41Ga,平均1.34(Ga).以上同位素特征表明花岗斑岩岩浆应源自成熟度较低的中元古代基底地壳物质.花岗斑岩的(206pb/204Pb)220Ma、(207pb/204Pb)220Ma和(206pb/204Pb)220Ma的平均值分别为17.875、15.604和38.296,与秦岭微陆块的中元古代基底和碧口地体碧口群的Pb同位素组成一致.考虑到前人获得碧口群的年龄为1.235～1.367Ga,而秦岭微陆块沿勉略缝合带向南仰冲到碧口地体之上.我们认为由碧口群等组成的俯冲板片的变质脱水熔融作用导致了阳山金矿带花岗斑岩的形成.因此,阳山金矿带的花岗斑岩是扬子与华北大陆中生代碰撞造山过程中形成的同碰撞花岗岩类.     

滇西北衙金矿区大沙地岩体地质特征、Sr-Nd-Pb同位素及地质意义

大沙地二长花岗斑岩体位于北衙金多金属矿区南部,是矿区内勘查控制的7个主要富碱斑岩体中唯一的隐伏岩体。本文对大沙地岩体成矿的地质特征进行了总结和探讨,发现大沙地岩体成矿表现出由岩体向外围地层依次发育斑岩型Cu-Au→矽卡岩型Cu(Mo)-Fe→热液脉型Au的矿化分带特征,显示出斑岩热液成矿系列特征。大沙地地区较万硐山主矿区相对发育Cu-(Mo)矿化类型而缺乏Au矿化,这可能与大沙地岩体的隐伏性及向深部富集Cu(44.7×10~(-6)~2254×10~(-6))、Mo(3.86×10~(-6)~24×10~(-6))等成矿相关微量元素的特征有关。大沙地二长花岗斑岩铅同位素相对变化较小,~(206)Pb/~(204)Pb、~(207)Pb/~(204)Pb、~(208)Pb/~(204)Pb分别在18.691~18.931、15.664~15.703和38.898~39.124之间。(~(87)Sr/~(86)Sr)i含量在0.70753~0.70852之间,ε_(Nd)(t)变化于-6.87~-8.60,Nd同位素二阶段亏损地幔模式年龄(t_(DM2))为1.4~1.5Ga,综合指示成矿物质来源于下地壳。包括大沙地岩体在内的北衙富碱斑岩还具有与滇西地区始新世钾质酸性岩中的角闪岩捕掳体相似的Sr-Nd-Pb同位素组成,推测富碱斑岩岩浆可能源自角闪岩相下地壳物质的部分熔融,而扬子西缘青藏高原主碰撞向晚碰撞过渡阶段(40~26Ma)挤压转换应力背景下,由地体斜向碰撞形成的金沙江-红河大型走滑深断裂带及其次级构造则控制了富碱斑岩岩浆的上升和侵位。     

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.     

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.     

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.