内蒙古亚干变质核杂岩与伸展拆离断层

本文阐明了内蒙古亚干变质核杂岩的构造组成与特征，特别是拆离断层本身及下盘中的各种伸展构造，对变质核杂岩的年龄也进行了较详细的讨论。亚干变质核杂岩）侏罗纪）与科迪勒拉的变质核杂岩（第三纪）的特征基本。相似。其基本构造要求：（１）下盘为糜棱状片麻岩；（２）绿泥石化礴岩；（３）假熔岩和燧石状碎裂岩或微角砾岩；（４）末变质或轻微变质的上船岩石和邻近拆离断层的一层断层泥或朱粘结的断层角砾。但与科迪勒拉区不同     

大别核部杂岩中斜长角闪岩的地球化学特征及其地质意义

大别核部杂岩单元中斜长角闪岩的地球化学特征对于认识大别核部杂岩单元的特征及归属有着十分重要的意义。本文对大别核部杂岩单元中斜长角闪岩的岩石地球化学特征及Sm-Nd 同位素特征进行了较系统研究。斜长角闪岩的 Nd亏损地幔模式年龄(t_(DM))有3个不连续年龄段,它们分别为2.50～2.92Ga(平均2.71Ga);1.79～2.47Ga(平均2.14Ga);1.07～1.57Ga(平均1.38Ga)。模式年龄为中元古代、古元古代的斜长角闪岩的等时线年龄分别为1444±180Ma、2220±210Ma,其模式年龄与等时线年龄在误差范围内一致。表明至少模式年龄为元古宙的斜长角门岩的t_(DM)可代表其原岩的近似形成年龄,从而证明大别核部杂岩单元中存在着古元古代、中元古代两期自亏损地幔分异的基性火山岩变质形成的斜长角闪岩。而模式年龄为新太古代的斜长角闪岩,其模式年龄能否代表其形成年龄还需要进一步研究。各期斜长角闪岩在地球化学特征上的差异表现得不明显。通过对其原岩性质研究表明:原岩主要为拉斑玄武岩,少数为钙碱性玄武岩。大别核部杂岩中斜长角闪岩原岩ε_(Nd)(t)反映出大别核部杂岩地区上地幔自古元古代到中元古代一直沿着亏损地幔 Nd 同位素的演化线演化发展,这种性质及演化趋势与扬子北缘及南秦岭早期上地幔 Nd 同位素性质及演化趋势十分     

康滇地轴冕宁杂岩的Sm-Nd同位素地质年代学初步研究

通过冕宁杂岩的稀土元素、微量元素及Sm—Nd同位素组成分析发现：杂岩核部二辉片麻岩微量元素以Th富集为特征，而典型的太古代灰色片麻岩则为Th亏损；分布于杂岩边部的英云闪长质片麻岩及花岗质片麻岩与灰色片麻岩宏观特征相似，且有Th，Nb亏损，但强不相容元素强烈富集，配分型式强烈右倾，也有别于太古代灰色片麻岩。两类岩石的Nd模式年龄均小于2000Ma，推测该杂岩的部分岩石原岩(二辉片麻岩及斜长角闪岩)形成时代可能为早元古代晚期，它们在晋宁期强烈的构造岩浆活动中发生角闪岩相变质。岩石的Nd模式年龄(2008Ma～766Ma)显示该区在元古代有较大规模的地壳增长，基底岩石的形成时代有别于扬子地台周边地区。     

内蒙古甘珠尔庙变质核杂岩

本文讨论了出露在大兴安岭主峰穹状复背斜核部的变质核杂岩。从岩石组合、变质温压条件、变形特征角度阐明了变质核杂岩的结构。从变质核杂岩各层之间的产状关系进一步探讨了变质核杂岩隆升时间以及与大兴安岭隆升的关系。最后通过核部侵位的超镁铁-镁铁质岩探讨了变质核杂岩隆升的深部背景。     

庐山变质核杂岩的变质变形及构造意义

庐山出露的变质核杂岩的构造层次具有典型的三层结构,即最上面的未变质沉积盖层、中间韧性流变层、核部的变质基底,其间分别以上剥离断层和拆离断层为分界线。上部沉积盖层以脆性变形为主,中间韧性流变层变形程度不一,但远离拆离带变质变形逐渐减弱,而核部的变质基底以强塑性变形为特征。对变质核杂岩南北两条地质剖面的分析,得到三个构造层次的岩石变质变形及岩性变化特征。区域动力学分析反映变质核杂岩东部原拆离带在五里正断层附近。拆离带中多硅白云母压力计得出的变质压力为0.6~1.1 GPa;锆石U-Pb年龄测试得到变质核杂岩的隆升时代为早白垩世。     

辽宁南部万福变质核杂岩的发现及其区域构造意义

根据宏观与微观构造测量,结合白垩纪沉积盆地组成与结构、区域岩浆活动性及其测年资料等的综合分析,揭示出在辽宁南部辽南变质核杂岩东侧存在另一个变质核杂岩构造,即万福变质核杂岩。该核杂岩具有典型的三层结构:拆离断层带由不同层次构造岩构成,上盘为元古宇岩石,下盘是太古宇岩石和就位于其中的同构造花岗质侵入体。万福变质核杂岩形成于早白垩世,与辽南变质核杂岩构成一个变质核杂岩对,两者在很多方面具有相似性。该变质核杂岩对的厘定可能为阐明华北晚中生代岩石圈的力学和流变学属性以及岩石圈减薄过程提供了依据。     

楼子店变质核杂岩韧性变形作用的40Ar/39Ar年代学约束

楼子店变质核杂岩以拆离系中韧性剪切与脆性拆离运动学不一致,有别于北美科迪勒拉变质核杂岩。构造分析表明,核杂岩两侧拆离系中韧性剪切具有统一的上盘向北东的剪切特征。采自核杂岩两侧韧性剪切带中的3个黑云母单矿物^40Ar／^39Ar年龄介于126～128Ma之间,西侧韧性剪切带中1个角闪石单矿物^40Ar／^39Ar年龄为134Ma,4个样品的坪年龄与对应的等时线年龄一致。角闪石和黑云母坪年龄记录的韧性剪切作用的时限为126～134Ma,并且显示出韧性伸展的特点。研究表明楼子店变质核杂岩两侧的韧性剪切带形成时间一致并具有相同的运动学,韧性剪切作用是核杂岩形成演化的一个重要阶段,这为核杂岩形成的韧性伸展阶段的约束提供了年代学证据。     

庐山变质核杂岩东侧的伸展拆离及构造意义

庐山变质核杂岩东侧的星子牛屎墩地区出露与西侧拆离带相似的伸展拆离滑脱、韧性流变的构造现象, 岩层整体呈现上盘向南东滑脱的正断层性质, 推测庐山变质核杂岩东侧的拆离带就在此处, 而并非五里正断层。东侧拆离带内岩石以糜棱岩、糜棱状岩石及混合岩为主, 并发育大量的长英质脉体, 形成温压较高, 埋深较大, 其糜棱岩带、构造片岩带保留完好。运动学涡度分析得到涡度W_k>0.75, 表明该拆离系为以单剪为主的一般剪切带。根据糜棱岩中长石的变形特征估算东侧拆离带的形成温度为650 ℃~700 ℃, 与西侧拆离带近于一致。锆石U-Pb年龄测定得到东侧拆离带的伸展年龄为140~135 Ma, 也代表了庐山变质核杂岩的形成时间。     

辽西医巫闾山变质核杂岩构造特征及其岩石组构的动力学分析

通过研究将辽西医巫闾山变质核杂岩构造要素划分为:变质核、拆离断层、中间过渡层、盖层和医巫闾山背形,并简述了其地质特征.采用X射线衍射法对医巫闾山花岗岩及周围不同时代岩石的不同层次变形构造开展了岩石组构特征研究,确定了韧-脆性构造变形时的力学性质和主应力方位,对变质核杂岩的形成演化进行了运动学和动力学分析.     

藏南萨迦拉轨岗日淡色花岗岩特征及与变质核杂岩的关系

藏南拉轨岗日带展布着串珠状变质核杂岩, 其内出露的淡色花岗岩体构成北喜马拉雅淡色花岗岩带.岩体既有在变质核杂岩内核中分布的, 亦有在滑脱系分布的, 岩体均表现出强力主动侵位的特征.淡色花岗岩可分为两期: 早期黑云母淡色花岗岩和晚期白云母淡色花岗岩.岩石高硅富铝, 含白云母±电气石±石榴石特征富铝矿物, 为S型花岗岩.北喜马拉雅淡色花岗岩结晶年龄为17~10Ma, 源岩为MCT上部基底副变质岩.当挤压体制与伸展体制转换时, 降压作用导致了岩浆的生成, 同时, 由于压力骤减, 年轻造山带更为塑性的下地壳物质与软层隆起导致上地壳伸展, 从而形成变质核杂岩, 岩浆对内核的上隆起到促进作用.      

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。     

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.     

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.