坚持专业特色 创一流品牌期刊     

赵霞  苏泽云  安珍 《山西地震》2014,(4):20-21

将《地震学刊》更名为《防灾减灾工程学报》10余年的历程进行了分析,阐述了《学报》采取诸多举措,从一个濒危的省级地方刊物成长为国内外认可的优秀核心期刊。其影响力不断扩大,学术水平不断提高,成为业内科研人员学术交流的前沿阵地。  相似文献   

Eutectic temperatures and melting relations in the Fe–O–S system at high pressures and temperatures     

Kyusei Tsuno  Eiji Ohtani 《Physics and Chemistry of Minerals》2009,36(1):9-17

We have investigated melting relations in the Fe–O–S ternary system in the pressure range of 15–27 GPa and 1873 K. Subsolidus phase relations are Fe, Fe₃S₂, and FeO up to 17 GPa and Fe, Fe₃S, and FeO above this pressure. The eutectic temperature slightly decreases from ambient pressure to 17 GPa, whereas increases above this pressure. The eutectic temperature in this study is 100 K lower than that in the Fe–S binary system. The oxygen content in the Fe–O–S eutectic liquid drops when the coexisting solid phases changes from FeS to Fe₃S₂. The cotectic lines in the ternary phase diagram lie close to the Fe–FeS binary axis. The isothermal sections indicate that oxygen solubility in the Fe–O–S liquid increases with increasing temperature, and with increasing sulfur content. The solubility of sulfur in the solid Fe has a maximum value at the eutectic temperature, and decreases with increasing temperature. Our results could have important implications for formation and composition of the Martian core.  相似文献   

江汉平原沉积环境演化及对三峡贯通的指示   总被引：4，自引：2，他引：2       下载免费PDF全文

王秋良  李长安 《第四纪研究》2009,29(2):352-360

选取江汉平原孔深400.59m的新沟钻孔,通过对其40Ma以来的沉积物进行岩性描述及粒度特征的研究,探讨了此岩芯剖面沉积环境的演变过程。结果表明,该岩芯垂直剖面沉积物颗粒基本构成是以砂、粉砂、粘土为主,沉积环境变化频繁。根据粒度参数特征所反映的沉积环境意义,划分出4个沉积阶段: 3.93～3.66MaB.P.(深度400.59～375.03m)为深湖相沉积环境,   3.66～2.17MaB.P.(深度 375.03～.195.90m)为河湖相沉积环境,   2.17～1.77MaB.P.(深度195.90～147.08m)为浅湖相沉积环境,   1.77MaB.P.～0.11kaB.P.(深度147.08～0m)为河湖相交替频繁的沉积环境;  从而揭示了江汉平原新沟钻孔4.0Ma以来的沉积环境的演变过程。对比江汉平原新沟孔和周老孔的磁学参数及磁性矿物特征的研究结果,发现在新沟孔深度109.15～98.82m间江汉平原水系曾发生过重要调整,江汉平原的沉积环境和物质成分均发生了重大改变。该层位可能就是长江三峡贯通的层位,其贯通时间新沟孔古地磁年龄约为1.0MaB.P.左右。  相似文献   

宾川小龙潭斑岩铜矿找矿方向思考     

张金学  王文超  雷阳艾  梅朴莲 《云南地质》2009,28(4):409-414

小龙潭近东西向核桃箐断层对岩体的控制起主导作用。核桃箐沟以北的斑岩露头总体为“模式”的外带。结合核桃箐沟断层的性质及其对地貌的影响,提出进一步找矿重点应转移至核桃箐沟南侧探寻斑岩体核部,打破在F2以北找矿的瓶颈,有望取得找中大型斑岩铜矿的突破。  相似文献   

Sound velocity of Fe3C at high pressure and high temperature determined by inelastic X-ray scattering     

《Comptes Rendus Geoscience》2019,351(2-3):190-196

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Classification of lacustrine sediments based on sedimentary components   总被引：2，自引：12，他引：2  

Douglas Schnurrenberger  James Russell  Kerry Kelts 《Journal of Paleolimnology》2003,29(2):141-154

This paper introduces a flexible sediment classification scheme for modern and ancient lake sediments employed at the Limnological Research Center, University of Minnesota. Our classification scheme emphasizes the macroscopic structure and microscopic components of the sedimentary matrix (clastic, chemical and biological) and can be applied to a wide range of lacustrine settings. Such a classification scheme is necessary to i) facilitate communication and collaboration between the highly interdisciplinary community of scientists that study lacustrine archives, ii) create a structure for comparative lacustrine sedimentological studies, and iii) take greater advantage of the great potential information recorded by changing depositional environments. Such a development is needed in light of current and planned Global Lake Drilling efforts and to expedite the creation of on-line, searchable databases of global lacustrine archives. A more comprehensive treatment of the topics discussed in this paper is available at: http://lrc.geo.umn.edu/services/handbook/sedclass.html.  相似文献   

Evidence and cause of climate cycles in polar motion     

H. Jochmann  E. Felsmann 《Journal of Geodesy》2001,74(10):711-719

 The long-term variation of polar motion contains a number of periods similar to climate cycles. Two possible causes for these long-term variations are mass redistributions produced by variations of atmospheric and oceanic circulation, and mass exchanges between the cryosphere and hydrosphere. Inner-core wobble, which can be inferred from the observed motion of the geomagnetic pole, is another phenomenon with periods similar to climate cycles. Only observations relating to mass redistributions caused by atmosphere dynamics and inner-core wobble are available for sufficiently long periods of time to investigate their influence on climate cycles in polar motion. Both processes contribute to climate cycles in polar motion, but they cannot completely explain these cycles. Possible sources of climate cycles are discussed. Received: 20 December 1999 / Accepted: 28 August 2000  相似文献   

Closure of the Fe-S-Si liquid miscibility gap at high pressure     

C. Sanloup 《Physics of the Earth and Planetary Interiors》2004,147(1):57-65

A high pressure investigation of melting relationships in the Fe-S-Si system has been conducted in a multi-anvil apparatus from 10 to 27 GPa and up to 2343 K. At 1 atm, the Fe-S-Si ternary system exhibits a vast miscibility gap [Raghavan, V., 1988. Phase diagrams of ternary iron alloys. Part 2: Ternary systems containing iron and sulphur. Indian Institute of Metals, Calcutta]. Quenched samples from experiments conducted at 10 and 12 GPa show an emulsion of immiscible liquids (an Fe-S melt and an Fe-Si melt). The liquid miscibility gap persists to at least 2343 K at 10 GPa. At 15 GPa, only one liquid is quenched, with a fine homogeneous dendritic texture. The results provide a mechanism to incorporate both S and Si as the light elements into the Earth’s core during a moderately high-pressure differentiation, consistent with geochemical models predicting up to 15 wt.% of light elements in the Earth’s core with 2-5 wt.% S and 7-10 wt.% Si. In contrast, for small planets such as Mars and Ganymede, differentiation took place within the pressure range of the miscibility gap. The composition of these cores is likely to be S-rich but Si-poor.  相似文献   

中国沉积学的今后发展:若干思考与建议   总被引：4，自引：0，他引：4  

颜丹平  周美夫  宋鸿林  刘敦一  王彦斌  汪昌亮  董铁柱 《地学前缘》2005,12(2):0-0

出露于北京西山房山岩体南北两侧的官地杂岩,主要由正片麻岩、斜长角闪岩组成,局部具混合岩化特征。对官地杂岩的形成时代及出露原因一直存在很大的争议。一种观点认为官地杂岩形成时代为太古宙,出露于中生代早期的区域伸展体制下,另一种观点则认为官地杂岩是中新元古界或古生界泥质变质岩,在房山岩体侵位过程中发生接触变质作用的产物。研究表明,官地杂岩是一套正片麻岩,其中的锆石核部为岩浆成因,而外部普遍发育较窄的浅色边。SHRIMP II锆石铀铅年龄测定获得锆石的一致曲线与不一致曲线上交点年龄值为(2 521 ±20) Ma,代表了新太古代的岩浆结晶年龄,从而证明官地杂岩原岩形成于新太古代。构造分析表明,官地杂岩与上覆中元古代蓟县系至早古生代地层间为剥离断层接触关系,并为房山岩体侵位和改造,证明是一个形成于房山岩体侵位前的变质核杂岩构造。但房山岩体的侵位并未对锆石的岩浆年龄和变质年龄产生明显影响。  相似文献   

Orientation,composition, and entrapment conditions of fluid inclusions in the footwall of the northern Snake Range detachment,Nevada     

《Journal of Structural Geology》2015

Footwall rocks of the northern Snake Range detachment fault (Hampton and Hendry's Creeks) offer exposures of quartzite mylonites (sub-horizontal foliation) that were permeated by surface fluids. An S–C–C′ mylonitic fabric is defined by dynamically recrystallized quartz and mica. Electron backscatter diffraction analyses indicate a strong preferred orientation of quartz that is overprinted by two sets of sub-vertical, ESE and NNE striking fractures. Analyses of sets of three perpendicular thin sections indicate that fluid inclusions (FIs) are arranged according to macroscopic fracture patterns. FIs associated with NNE and ESE-striking fractures coevally trapped unmixed CO₂ and H₂O-rich fluids at conditions near the critical CO₂–H₂O solvus, giving minimum trapping conditions of T = 175–200 °C and ∼100 MPa H₂O-rich FIs trapped along ESE-trending microcracks in single crystals of quartz may have been trapped at conditions as low as 150 °C and 50 MPa indicating the latest microfracturing and annealing of quartz in an overall extensional system. Results suggest that the upper crust was thin (4–8 km) during FI trapping and had an elevated geotherm (>50 °C/km). Footwall rocks that have been exhumed through the brittle-ductile transition in such extensional systems experience both brittle and crystal-plastic deformation that may allow for circulation of meteoric fluids and grain-scale fluid–rock interactions.  相似文献