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1.
安徽茂林岩体为中国东部中生代皖南构造-岩浆带中的一个浅层侵入岩体,是檀树岭钼矿和湛岭钼矿的成矿母岩。该岩体的主要岩性为花岗闪长岩、花岗斑岩、斑状花岗闪长岩、二长花岗岩等。对茂林花岗闪长岩体进行LA-ICP-MS锆石UPb测年,结果显示锆石Th/U值为0.38~0.66,为典型的岩浆成因锆石。花岗闪长岩~(206)Pb/~(238)U年龄加权平均值为140.8±0.8Ma(n=19,MSWD=2.3),结合锆石自形、岩浆环带发育等特点,该年龄为茂林花岗闪长岩的成岩年龄,显示岩体形成于早白垩世。锆石Hf同位素分析结果显示,茂林花岗闪长岩锆石振荡岩浆环带具负εHf(t)值(-9.7~-6.2),揭示花岗闪长岩主要形成于下地壳的熔融。 相似文献
2.
浦桑果是近年来西藏冈底斯成矿带内发现的唯一一个富钴矽卡岩型铜多金属矿床,铜、铅、锌品位高,开发价值巨大。矿区主要出露黑云母花岗闪长岩和闪长玢岩中酸性侵入岩体,岩体形成时代均为中新世（13~14 Ma）,但其岩体含矿性目前尚未查明,是否具有斑岩型铜矿成矿潜力值得进一步探讨和研究。本文主要采用LA- ICP- MS原位成分分析方法分别对黑云母花岗闪长岩和闪长玢岩中锆石展开系统的原位微量元素分析。分析结果表明,黑云母花岗闪长岩和闪长玢岩中锆石均发育典型的振荡环带结构,两种岩体具有相似的REE配分模式、Ce正异常和Eu负异常特征,锆石成因类型属于典型的岩浆锆石类,锆石主要结晶形成于陆壳环境。锆石初始饱和温度和锆石Ti结晶温度计算结果表明,黑云母花岗闪长岩锆石初始饱和温度范围为633~645℃,锆石Ti结晶温度为658~817℃;闪长玢岩锆石初始饱和温度分布在549~626℃,锆石Ti结晶温度为640~772℃,锆石初始饱和温度均低于锆石Ti结晶温度,综合指示矿区中酸性岩体形成过程中存在多期次岩浆熔体的补给作用。锆石n(Ce4+)/n(Ce3+)、EuN/Eu*N、微量元素Dy/Yb、(Ce/Nd)/Y值与氧逸度（ΔFMQ）特征表明,黑云母花岗闪长岩较闪长玢岩具有更高的氧逸度范围（ΔFMQ+0. 44 ~ ΔFMQ+3. 86）和相对高的水含量,从而更有利于浦桑果矿区铜、硫等成矿元素在岩浆中进一步富集成矿,且矿区可能发育中—大型规模的金属矿床,然而进一步发育斑岩型铜矿床的可能性较低。 相似文献
3.
柯村花岗斑岩位于九华山国家地质公园西部,九华山岩体西侧。LA-ICP-MS 锆石U-Pb年代学研究表明:该花岗斑岩的侵入时间为125.8±0.9 Ma,与九华山岩体的侵入时间相近,属于早白垩世岩浆活动的产物; 九华山柯村花岗斑岩富硅、富碱、富集不相容元素,亏损Sr、Ba、Ti等元素,具有较高的10 000×Ga/Al值和锆石饱和温度,地球化学特征与A型花岗岩相似,形成于伸展构造环境,表明在125 Ma左右,皖南地区已经由早期相对挤压的构造环境转变为伸展构造环境。 相似文献
4.
皖南祁门地区东源钨钼矿区花岗闪长斑岩SHRIMP
锆石U-Pb年龄和Hf同位素特征 总被引：11，自引：1，他引：10
江家等系列花岗闪长斑岩是皖南祁门县东源钨钼矿区含矿岩体的组成部分,位于东源花岗闪长岩的西侧。对江家和方村花岗闪长斑岩进行的SHRIMP锆石U-Pb测年结果表明,江家、方村花岗闪长斑岩的结晶年龄为149~152Ma,与富钨的东源花岗闪长岩相近。岩石地球化学和锆石Hf同位素分析显示,江家等系列花岗闪长斑岩源区具有复杂的多成分端元,其中老锆石核的正εHf值反映了成岩岩浆对晋宁期岩浆岩的继承,震荡岩浆环带的负εHf值(-39.5~-2.86)指示源区的主要成分为古老的地壳物质,有少量地幔物质的混染。全岩锆石饱和温度(737~913°C)显示岩浆组成中有幔源物质的贡献。 相似文献
5.
江家等系列花岗闪长斑岩是皖南祁门县东源钨钼矿区含矿岩体的组成部分,位于东源花岗闪长岩的西侧。对江家和方村花岗闪长斑岩进行的SHRIMP锆石U-Pb测年结果表明,江家、方村花岗闪长斑岩的结晶年龄为149~152Ma,与富钨的东源花岗闪长岩相近。岩石地球化学和锆石Hf同位素分析显示,江家等系列花岗闪长斑岩源区具有复杂的多成分端元,其中老锆石核的正εHf值反映了成岩岩浆对晋宁期岩浆岩的继承,震荡岩浆环带的负εHf值（-39.5~-2.86）指示源区的主要成分为古老的地壳物质,有少量地幔物质的混染。全岩锆石饱和温度（737~913°C）显示岩浆组成中有幔源物质的贡献。 相似文献
6.
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。 相似文献
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太行山北段位于华北克拉通中部,以发育中生代中酸性岩浆岩及多个大中型斑岩-矽卡岩铜钼矿床和金矿床为主要特征,最近在南部赤瓦屋岩体内部发现新类型铜钨矿体。文章选择赤瓦屋岩体为对象,开展不同岩相详细的野外地质和锆石U-Pb测年工作,确定赤瓦屋岩体不同岩性的成岩时代,探讨其地质意义。研究表明,赤瓦屋岩体有边缘相石英闪长岩、边缘相花岗闪长岩和中心相斑状花岗闪长岩及晚期中酸性岩脉,其中铜钨矿化主要发育于中心相斑状花岗闪长岩。石英闪长岩、花岗闪长岩、斑状花岗闪长岩和花岗闪长斑岩脉的锆石U-Pb谐和年龄分别为(134±1)Ma、(133±1)Ma、(131±2)Ma和(128±1)Ma,表明赤瓦屋岩体不同岩相体形成于早白垩世(134~131Ma)。结合区域年代学资料,提出太行山北段晚中生代至少存在两期岩浆-成矿事件。 相似文献
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江西东乡花岗斑岩LA-ICP-MS锆石U-Pb年龄、地球化学特征及其地质意义 总被引：1，自引：0，他引：1
通过对东乡铜矿花岗斑岩进行岩石地球化学特征、锆石U-Pb定年研究,探讨其岩石成因、构造环境、形成时代与成矿的关系。东乡花岗斑岩的LA-ICP-MS锆石U-Pb年龄为156.4±1.5~161±1.0Ma。该岩体为高钾钙碱性系列,轻稀土元素富集,重稀土元素较亏损,具有明显的负Eu异常。微量元素富集大离子亲石元素,而亏损高场强元素。地球化学特征表明,东乡岩体形成于碰撞构造环境,岩浆来源于地幔,但形成演化期间经历了地壳物质的同化混染。该区矿石与花岗斑岩的稀土元素配分曲线存在一定的相似性,且成矿时间与岩浆侵入时间相近,表明岩浆侵入对东乡铜矿床的形成具有重要贡献。 相似文献
9.
相山铀矿田是中国迄今为止发现的最大的火山岩型铀矿床,其北部主要铀矿类型为花岗斑岩型铀矿床,铀成矿在时空和成因上与超淺成侵入相的花岗斑岩有关。前人多针对某一具体矿床含矿主岩开展工作,获得的花岗斑岩成岩年龄数据相差较大,影响了对相山花岗斑岩型铀矿的深入研究。选择相山北部横涧、游坊、沙洲、云际等铀矿床的含矿主岩——花岗斑岩系统开展野外地质调查、地球化学特征和LA-ICP-MS锆石U-Pb定年研究,以期厘定相山花岗斑岩型铀矿床含矿主岩的成岩时代和成因类型。花岗斑岩LA-ICP-MS锆石U-Pb定年结果显示,横涧、游坊、沙洲、云际的花岗斑岩206Pb/238U年龄加权平均值分别为135.6±1.3Ma(MSWD=0.45,n=26)、136.2±1.3Ma(MSWD=1.2,n=21)、133.4±11Ma(MSWD=0.67,n=24)及134.3±1.1Ma(MSWD=0.88,n=25),集中在132~137Ma之间,属于早白垩世。研究认为,相山北部花岗斑岩成因类型界于A型花岗岩与S型花岗岩之间的过渡型,为A-S型花岗岩。花岗斑岩岩浆起源于中元古代地壳,地壳物质作为主要成分参与了花岗斑岩的形成,同时有少量地幔物质的加入。花岗斑岩为板内构造界境下伸展体制的产物,可能是由于太平洋板块俯冲后,因板块后撤导致岩浆侵入作用的结果。 相似文献
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为探讨辽东半岛中生代闪长岩类岩石成因及其形成构造背景，选取辽东半岛岫岩西南部黄岭岩体为研究对象，开展岩相学、锆石LA-ICP-MS U-Pb年代学、Hf同位素地球化学和岩石地球化学研究.结果表明:黄岭岩体由黑云母二长闪长岩组成；锆石LA-ICP-MS U-Pb年龄为127.4±1.9 Ma，成岩为早白垩世；岩石地球化学元素特征表明，黄岭黑云母二长闪长岩具高钾钙碱性，轻稀土元素富集，重稀土亏损，富集Rb、Zr、K等大离子亲石元素，亏损Nb、P、Ti等高场强元素，正Eu异常；εHf（t）值为－20.1~－18.0，二阶段Hf模式年龄TDM2为2 316~2 450 Ma，揭示二长闪长岩可能是古元古代古老地壳部分熔融形成.结合区域构造演化推测黄岭岩体形成于古太平洋板块向欧亚板块俯冲挤压后折返伸展的构造背景. 相似文献
11.
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
12.
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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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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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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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
18.
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
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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