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1.
对张广才岭南部一面坡花岗岩的地质学、岩石学、地球化学及锆石U-Pb年龄研究表明,岩石富硅富铝,属于过铝质岩石(A/CNK=1.04~1.07),全碱(K2O+Na2O)含量为8.24%~8.85%,K2O/Na2O值为1.58~1.68,属于高钾钙碱性系列I型花岗岩。岩石富集LREE、Rb、Th、U、K,相对亏损Nb、Ta、P、Ti,具有明显的Eu负异常,LA-ICP-MS锆石206Pb/238U年龄加权平均值为211Ma±4Ma(MSWD=1.4,2σ),代表了花岗岩的结晶年龄。岩石具有相对亏损的锆石Hf同位素组成(εHf(t)=+1.75~+13.81),TDM2为367~1136Ma。结合区域构造环境分析,认为一面坡晚三叠世花岗岩属于I型花岗岩,可能形成于后碰撞伸展构造环境,是岩石圈伸展阶段新增生下地壳物质发生部分熔融的产物。 相似文献
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义敦岛弧带夏塞早白垩世A型花岗岩成因:锆石U-Pb年代学、地球化学及Hf同位素制约 总被引：3，自引：0，他引：3
义敦岛弧带晚中生代侵入岩体目前仍缺乏高精度的年代学数据制约,其成因也存在争论。作者首次在岛弧带中段夏塞银铅锌多金属矿区发现与成矿关系密切的黑云母二长花岗岩。本文对其开展了年代学、地球化学和Hf同位素分析,探讨成因及构造背景。LA-ICP-MS锆石U-Pb定年结果为103±1 Ma(MSWD=0.5),为早白垩世晚期岩浆活动产物。花岗岩属高钾钙碱性岩系,具有高硅、富碱和铁、贫钙和镁特征,Si O2含量为72.94%~74.98%,K2O+Na2O=7.56%~8.08%,铝饱和指数A/CNK=1.06~1.10,属弱过铝质岩石。岩石富集Zr、Hf等高场强元素和U、Th等大离子亲石元素,明显亏损Ba和Sr。REE具有明显的Eu负异常(δEu=0.13~0.25),总体呈较陡右倾的LREE富集和HREE相对亏损特征。岩相学和地球化学显示其为铝质A型花岗岩。Hf同位素组成εHf(t)=–2.7~0.6,二阶段模式年龄TDM2=925~1095 Ma。地球化学及Hf同位素揭示夏塞岩体为软流圈地幔与壳源长英质岩浆混合成因,并经历了斜长石、正长石和褐帘石等矿物的分离结晶。夏塞花岗岩体具有后碰撞花岗岩特征,形成于早白垩世晚期弧-陆碰撞造山后伸展构造背景。 相似文献
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滇西腾冲—梁河古近纪花岗岩锆石U-Pb定年、Hf同位素及地球化学 总被引：1，自引：0，他引：1
内容提要：滇西腾冲–梁河地区发育古近纪二长花岗岩和钾长花岗岩,记录了印度–欧亚大陆碰撞的岩浆活动信息。二长花岗岩的锆石U-Pb年龄为51.4±0.4Ma,其176Hf/177Hf比值为0.282554~0.282592,εHf(t)= -6.65~-5.30,其二阶段模式年龄为1.46~1.55Ga。腾冲–梁河古近纪花岗岩以高SiO2 (68.96%~78.68%)、高K2O (4.56%~6.29%)和高Al2O3(12.40%~16.42%)为特征,K2O/Na2O比值为0.93~7.24,Al2O3>(K2O+Na2O),A/CNK值为0.99~2.31,属于富钾钙碱性偏铝–强过铝质花岗岩;绝大多数样品具有强烈的负Eu异常(Eu/Eu*为0.19~0.51),富集Cs、Rb,亏损Sr、P、Ti、Ba、Nb、Ta,具有Pb的正异常。元素地球化学特征指示,其主要源于区域上地壳变质杂砂岩的部分熔融;结合区域地质,认为腾梁地区62~51Ma的花岗岩是对印度–欧亚大陆碰撞高峰期的岩浆响应。 相似文献
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塔里木盆地东北部新元古代花岗质岩浆活动及地质意义 总被引：1，自引：0，他引：1
库车坳陷东部侵入于元古宇基底变质岩中的黑云母二长花岗岩属于高钾钙碱性岩系,岩石具有富硅(SiO2=75.77%～77.79%)、高碱(Na2O+K2O=6.90%～7.95%)、富钾(K2O/Na2O=1.21～1.98)、低TiO2(0.06%～0.13%,平均0.08%)和准铝质(铝饱和指数A/CNK=0.92～1.15,平均1.07)的特点.岩石明显富集Rb、Th、K、Nd、Hf、Zr、Tb、Y和Yb,亏损Ba、U、Nb、Ta、Sr、P、Sm、Ti等元素,具有明显的负Eu异常(δEu=0.06～0.11,平均0.10).地球化学特征表明该花岗岩起源于中-下地壳的部分熔融.对花岗岩进行的LA-ICP-MS锆石U-Pb同位素地质年代学研究,获得了646.5±3.9 Ma的206Pb/238U加权平均年龄,说明花岗岩形成于早震旦世,而不是以前认为的石炭纪.结合区域地质资料分析认为,这次岩浆事件是塔里木地块基底在Rodinia超大陆裂解过程中的产物. 相似文献
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滇西腾冲—梁河地区发育古近纪二长花岗岩和钾长花岗岩,记录了印度-欧亚大陆碰撞的岩浆活动信息。二长花岗岩的锆石U-Pb年龄为51.4±0.4 Ma,其176 Hf/177 Hf值为0.282554~0.282592,εHf(t)=-6.65~-5.30,其二阶段模式年龄为1.46~1.55Ga。腾冲—梁河古近纪花岗岩以高SiO2(68.96%~78.68%)、高K2O(4.56%~6.29%)和高Al2O3(12.40%~16.42%)为特征,K2O/Na2O值为0.93~7.24,Al2O3(K2O+Na2O),A/CNK值为0.99~2.31,属于富钾钙碱性偏铝—强过铝质花岗岩;绝大多数样品具有强烈的负Eu异常(Eu/Eu*为0.19~0.51),富集Cs、Rb,亏损Sr、P、Ti、Ba、Nb、Ta,具有Pb的正异常。元素地球化学特征指示,其主要源于区域上地壳变质杂砂岩的部分熔融;结合区域地质,认为腾梁地区62~51Ma的花岗岩是对印度-欧亚大陆碰撞高峰期的岩浆响应。 相似文献
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本文对新疆阿尔泰南缘乌吐布拉克铁矿区斜长花岗岩和黑云母斜长花岗岩进行了锆石LA-ICP-MS U-Pb年龄测定,分别获得了385.6±2.3 Ma（MSDW=0.13）和387.7±2.1 Ma（MSDW=0.23）的谐和年龄,两者为中泥盆世早期同源岩浆侵入体。乌吐布拉克铁矿的形成与岩浆侵入活动密切相关,据此限定铁矿成矿时代略晚于388～386 Ma,为中泥盆世早期成矿。乌吐布拉克斜长花岗岩与黑云斜长母花岗岩均具有高硅（SiO2=66.01%～79.14%）、富钠贫钾（Na2O＞K2O）的特点。A/CNK〖HT4”〗{A/CNK=n(Al2O3)/\n(CaO)+n(Na2O)+n(K2O)]}值均小于1.1,表明两者为准铝质低钾花岗岩。微量元素表现为富集Th、Ta、Hf等高场强元素,亏损Rb 、Ba、K、Sr、P大离子亲石元素。稀土元素表现为轻稀土相对富集,轻重稀土元素分馏明显[(La/Yb)N=2.46～7.24],具有中等或强的Eu负异常。结合区域地质资料,认为乌吐布拉克矿区花岗岩形成于与板块俯冲有关的活动大陆边缘的陆缘弧环境中。 相似文献
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龙王(石童)A型花岗岩地球化学特征及其地球动力学意义 总被引：11，自引：0，他引：11
龙王花岗岩岩体产于华北克拉通南缘,岩石类型主要为黑云母钾长花岗岩,局部见有霓辉石花岗岩。岩体高硅(SiO2=72.17%～76.82%)、富碱(K2O+Na2O=8.28%～10.22%,K2O/Na2O>1),碱性指数AI(agpaitic index)=0.84～0.95,分异指数DI=95～97,铝指数ASI(aluminium saturation index)=0.96～1.13。含铁指数高(FeO/(FeO+Mg)=0.90～0.99),岩石为准铝质至弱过铝质、碱性—碱钙性、铁质A型花岗岩。岩石富集大离子亲石元素,稀土元素含量很高(854～1572μg/g);高场强元素(Nb、Ta、Zr、Hf)的富集程度明显低于大离子亲石元素,因此在微量元素蛛网图上呈相对亏损特征;岩石显著亏损Ba、Sr、Ti、Pb;εNd(t)=-4.5～-7.2,Nd模式年龄为2.3～2.5Ga。εHf(t)=-1.11～-5.26,模式年龄tHf1=2.1～2.3Ga,tHf2=2.4～2.6Ga。黑云母钾长花岗岩中的锆石主要为无色透明柱状晶体,CL图像多数显示清晰的岩浆成因的韵律环带结构,锆石LA-ICPMSU-Pb年龄为... 相似文献
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虎头崖铅锌多金属矿床位于东昆仑祁漫塔格地区,矿区内中酸性侵入岩体广泛发育,且与成矿关系密切。LA-ICP-MS锆石U-Pb同位素年龄测试表明,虎头崖Ⅴ矿带外围花岗闪长岩形成时代为(224.3±0.6)Ma,Ⅷ号矿带矿体下部正长花岗岩形成时代为(239.7±0.8)Ma,岩体形成时代为中—晚三叠世。岩石地球化学表明,花岗闪长岩富钾贫钠(K2O/Na2O为2.02~2.88),无明显负Eu异常(δEu为0.68~1.06),富集Rb、Th、U、K等大离子亲石元素,明显亏损Nb、P、Ti等元素,属I型花岗岩;正长花岗岩具高硅、富碱、低铁镁、贫钙磷钛的特征,负Eu强烈(δEu为0.08~0.26),富集Rb、Th、U、K,亏损P、Ti、Ba、Sr,属高分异I型花岗岩;二者均形成于后碰撞构造背景;Hf同位素组成不均一,指示其经历了壳幔岩浆混合作用,幔源物质的加入可能带来了丰富的成矿物质。 相似文献
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国庆钾长花岗岩岩体出露于蒙古自治区额济纳旗西南部的盘陀山一带,北邻牛圈子-洗肠井缝合带,LA-ICP-MS测得该岩体的U-Pb年龄为439.1±8Ma。岩体SiO2含量73.31%～74.36%,A/CNK>1.1,K2O/Na2O=1.25～1.40,里特曼指数介于2.06～2.22之间,属于高钾钙碱性、过铝质花岗岩系列,岩体富集大离子亲石元素,亏损高场强元素。稀土和微量元素分析显示钾长花岗岩总体轻稀土元素富集,轻、重稀土元素分馏较低,具有较明显Eu负异常(δEu=0.65～0.77),具K、Rb、Ba、Th等元素富集,Nb、Ce、Zr、Hf、Sm、Y、Yb等元素亏损的特征。综合分析表明,国庆钾长花岗岩为壳源S型同碰撞花岗岩;结合区域构造演化历史,认为国庆钾长花岗岩为古老地壳物质重熔形成,是早志留世月牙山-洗肠井古洋盆闭合同碰撞阶段的产物。同时对该区志留—泥盆纪碰撞伸展环境下成矿前景初步分析,为矿床研究和区域矿产预测工作提供参考。 相似文献
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额尔宾山花岗岩岩体位于南天山晚古生代侵入岩带,对该花岗岩进行锆石U-Pb定年获得296.1±1.8Ma的年龄,为早二叠世。岩石主量元素分析结果表明,该花岗岩的Si O2含量为66.96%~67.3%,富碱(Na2O+K2O=7.53%~7.97%),K2O/Na2O1(1.15~1.27),属高钾钙碱性系列岩石;Al2O3为15.56%~15.62%,Al2O3K2O+Na2O+Ca O,属于过铝型。岩石稀土元素配分模式呈现轻稀土元素(LREE)富集((La/Yb)N=27.03~30.62)、重稀土元素(HREE)亏损((LREE/HREE)=18.2~20.1)、具有中等程度的负Eu异常(δEu=0.64~0.68)。微量元素判别结果显示,其具有I-A型花岗岩过渡的特征。结合区域地质背景综合分析,初步认定该岩体可能形成于南天山同碰撞向后碰撞构造体制转换时期,据此可以推测南天山洋盆闭合时限至少应该在早二叠世以前。 相似文献
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S. Viswanathan K. Surya Prakash Rao B. Mahabaleswar 《Journal of the Geological Society of India》2013,82(6):621-627
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. 相似文献
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奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
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 相似文献
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E. M. Prasolov S. A. Sergeev B. V. Belyatsky E. S. Bogomolov K. A. Gruzdov I. N. Kapitonov R. Sh. Krymsky V. O. Khalenev 《Geochemistry International》2018,56(1):46-64
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. 相似文献
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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. 相似文献
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17.
岩石密度和超高压岩石折返速率 总被引：1，自引：3，他引：1
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。 相似文献
18.
Alexander E. C. Broberg J. S. Kehren A. R. Graziani M. M. Turri W. L. 《Environmental Geology》1993,22(4):353-361
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. 相似文献
19.
Mercury,arsenic, antimony,and selenium contents of sediment from the Kuskokwim River,Bethel, Alaska,USA 总被引：1，自引：0，他引：1
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. 相似文献
20.
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. 相似文献