Sm-Nd同位素年代学实验条件的研究及标准岩样BCR-1的测定

本文报道了Sm,Nd的化学分离、质谱测定方面的工作结果。样品添加~150Nd-~147Sm混合稀释剂。首先以以HCl为洗脱剂,从硅酸岩样品中分离出稀土组分,再以α-HIBA为络合洗脱剂,从稀土组分中分离纯Sm,Nd。在MAT261质谱计上测定其同位素组成,~143Nd/~144Nd比值测定精度优于5×10~(-5)。稀释法测量美国标准样BCR-1检验,得到其~147Sm/~144Nd比值为0.13843±5(2σ_m),~143Nd/~144Nd比值为0.511837±8(2σ_m)。Nd全流程本底为250×10~(-12)g,Sm为50×10(-12)g。因此不必进行本底校正。     

新型高灵敏度Sm-Nd同位素分析方法

低本底高灵敏度Sm—Nd同位素分析方法对石榴子石Sm—Nd定年、陨石Sm—Nd年代学及地球化学、高度亏损超镁铁岩Sm—Nd同位素研究以及环境样品Sm—Nd同位素地球化学研究等领域具有重要的意义。     

用同位素稀释质谱法测定微量稀土元素

用同位素稀释质谱法测定高纯物中或植物样品中8种微量稀土元素Ce,Nd,Sm,Eu,Gd,Dy,Er和Yb,讨论干扰和分馏偏差校正.该法精密度好于1％,检出限小于2.3×10~(-9)g,准确度优于±5%.     

利用DCTA和HIBA快速有效分离Rb-Sr、Sm-Nd的方法

介绍了一种新的Rb_Sr、Sm_Nd化学分离方法,以用于地质样品的同位素测试.方法选用AG50W×8阳离子交换树脂,并先后采用不同的淋洗剂进行分离提纯.首先用常规方法使用盐酸作为淋洗剂将Rb_Sr和REE分开并与其它大部分元素分离,然后使用DCTA和嘧啶的混合溶液(D.P.E.)作为淋洗剂分离Rb和Sr,使用HIBA作为淋洗剂在很小体积(0.6mL)的阳离子交换树脂中分离Sm和Nd.使用这样的分离方法可以有效的将一些干扰离子(如Mg、Ca、Ba)和Sr分离,同时使用该分离方法可以提高分离效率,缩短分离时间,减少试剂用量,降低实验过程空白.用该方法分离国际玄武岩标样BCR_2后的Sr同位素测试结果(87Sr/86Sr=0.705018±3)和Nd同位素测试结果(143Nd/144Nd=0.512616±9)与已经报道的测试结果基本一致,说明本次研究采用的新分离方法效果良好.     

蛾眉山玄武岩地球化学和大陆地幔演化

峨眉清音、会东唐坊和攀枝花二滩三个地区峨眉山玄武岩系岩石测得的多元素丰度数据,表明峨眉和唐坊剖面岩系低MgO,二滩剖面岩系高MgO,但三个剖面玄武岩TiO_2,K_2O和不相容微量元素的丰度高,具有碱性玄武岩系典型的稀土元素特征曲线。峨眉剖面玄武岩~(87)Sr/~(88)Sr=0.7066—0.7082;Rb/Sr=0.02—0.12;~(143)Nd/~(144)Nd=0.51171—0.51174。根据微量元素模式计算,结合岩石学研究,三个地区原始母岩浆可能都来自一个均匀交代了的富集地幔源区部分熔融产物。进而对源区成分,熔融程度和分异过程进行了模拟,并提出了一种地幔富集作用的机理。     

西藏多不杂铜矿床锶、钕、铪同位素特征及其地质意义

探讨西藏自治区改则县多不杂铜矿床的成矿物质来源及成矿动力学原理。选择矿区内花岗闪长斑岩全岩、黄铁矿以及锆石样品,测试锶、钕、铪同位素组成。结果显示,多不杂铜矿床样品中的Sr初始值介于幔源镁铁质岩石Sr同位素的平均值和壳源硅铝质岩石Sr同位素的平均值之间,靠近幔源镁铁质岩石,暗示花岗闪长斑岩的原始岩浆起源于地幔,在上升侵位时与硅铝质地壳物质发生交换,使其具有壳幔混染特征;花岗闪长斑岩具有相对高(~(87)Sr/~(86)Sr)i、低~(143) Nd/~(144) Nd的特征是交代富集地幔的反映,锶同位素的迁移行为与成矿元素相似,携带含矿物质的流体由斑岩体向围岩进行了迁移,并与围岩之间发生充填交代,导致变质砂岩含矿;锆石ε_(Hf)(t)值基本为正值,且变化范围较大,是有较多幔源组分参与成岩的标志,指示幔源岩浆作用过程中伴有地壳流体的混染。矿床成因综合研究初步揭示多不杂铜矿床是由地幔流体作用引发壳幔物质混染叠加成矿。     

黔中白云岩风化剖面的钕、锶同位素组成及演化

为了限定云贵高原岩溶台地白云岩上覆的平坝红色风化壳剖面的物质来源,探讨可溶性岩化学风化过程中同位素的地球化学演化特征,对该剖面进行了Nd-Sr同位素的综合分析．结果显示,剖面全岩样品的^87Sr／^86Sr比率从0．708到0．747涵盖了非常大的范围．“。Nd／“。Nd比率在残积物中较为均一,为0．512-0．5124（∈Nd为-9．6--11．5）,而^147Sm／^144。Nd比率变化较大,为0．08400．2257．在风化前缘中,发现随着风化程度增强,Sm／Nd比率降低和Sr浓度增加的特征．这种同位素组成的变化,主要是风化早期阶段水岩相互作用,伴随着差异性风化Rb／Sr和Sm／Nd比值的不同矿物造成．剖面下部样品中赋存含磷矿物的风化是剖面Nd—Sr同位素演化的一个重要原因．发现剖面由下至上,出现亏损地慢钕同位素模式年龄逐渐减小的趋势,可能是因为样品风化程度不同造成的．     

黑龙江科洛晚新生代火山岩K—Ar定年和地球化学

对采自8个火山锥和其它产状的15个火山岩样品和一个幔源包体样品进行了系统的岩石薄片观察,常量元素、微量元素和稀土元素的化学分析,K-Ar定年及氧、锶和钕同位素测定。显微镜下首次发现了贵橄榄石的贯穿双晶,包括四角星状和六角星状双晶。化学分析表明这是一套SiO_2不饱和、高K、Mg而贫Ca,同时特别富集LREE、不相容元素和地幔元素的岩浆。全岩的δ~(18)O值略高于初始地幔,Sr和Nd同位素组成在~(87)Sr/~(86)Sr-~(143)Nd/~(144)Nd图解上,落在第Ⅳ象限地幔排布的延长线上,并且靠近坐标原点,显示初始地幔的特征,K-Ar表现年龄值域在0.03Ma和2.98Ma之间,大多数落在晚更新世。地幔包体表现年龄约为70Ma,中生代的玄武岩年龄在93.3Ma和95.5Ma之间。趋势分析表明年青火山仍有喷发的可能性、显微镜下挑除橄榄石捕虏晶后的对比定年实验给出了有益的提示:我国东北和东部大面积分布的晚新生代橄榄玄武岩过去的定年可能都偏老了。     

南兴安岭晚中生代火山岩的岩石成因(II):Pb同位素制约

 对南兴安岭地区晚中生代火山岩的Pb同位素进行了分析，结合其主微量元素和Sr-Nd同位素地球化学特征，探讨了火山岩的岩石成因。满克头鄂博组低钾拉斑-钙碱性玄武安山岩表现出富集LILE、LREE和HFSE亏损元素地球化学特征以及稍高放射性成因Sr、Pb (⁸⁷Sr/⁸⁶Sr=0.704 88～0.704 99; ²⁰⁶Pb/²⁰⁴Pb=18.18～18.23)和弱相对亏损至弱富集的Nd同位素组成(ε_Nd((t)=-0.12～+0.68)，其来源于俯冲沉积物参与改造富集地幔熔融源区。该组的英安岩-流纹岩较基性岩浆具有稍高放射性成因Sr、Pb (⁸⁷Sr/⁸⁶Sr=0.705 22～0.707 09; ²⁰⁶Pb/²⁰⁴Pb=18.16～18.33)和低Nd同位素组成 (ε_Nd(t))=-1.5～-0.4), 且在空间上与玄武岩共生，为玄武质岩浆结晶分异，并同化混染作用 (AFC)的产物。玛尼吐组英安岩具有与现代俯冲带adakite岩石相似的特征；在Sr-Nd-Pb同位素组成上，它们较同期或近期玄武安山岩更低Sr、Pb (⁸⁷Sr/⁸⁶Sr=0.704 09~0.704 25;²⁰⁶Pb/²⁰⁴Pb=18.15~18.17)和高Nd同位素比值(ε_Nd((t))=+0.9~+2.1)，为造山带下地壳镁铁质岩石的部分熔融产物。     

安徽铜陵白芒山辉石闪长岩体的成因:Sr-Nd-Pb-O同位素制约

白芒山辉石闪长岩体位于安徽铜陵狮子山矿田内,属于高钾钙碱性岩系,形成时代为燕山晚期.运用Sr、Nd、Pb和O同位素综合示踪技术,探讨了该岩体的成因.研究结果表明,白芒山辉石闪长岩锶同位素初始值(ISr)变化于0.707291~0.707315之间;εNd(t)值变化于-13.04~-14.01之间;全岩δ18O值为10.2‰~11.7‰;初始铅同位素组成(t=142.9Ma)为:(206Pb/204Pb)i=17.9790~18.3267,(207Pb/204Pb)i=15.5125~15.6578,(208Pb/204Pb)i=38.1000~38.2117.结合安徽沿江地区岩浆岩研究资料可以看出,白芒山辉石闪长岩体为壳、幔岩浆混合成因,成岩物质起源于扬子下地壳和富集岩石圈地幔的部分熔融,是富集岩石圈地幔和扬子下地壳物质混合的产物,成岩过程后期经历了上地壳物质的混染作用影响.其中富集岩石圈地幔的形成主要与俯冲洋壳与陆壳析出流体的混染与交代作用有关.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.