中下扬子地区的壳幔结构及其与地震相关性的研究

针对中下扬子地区人口稠密、经济建设蓬勃发展、而其地壳构造十分复杂、天然地震比较活跃的现实情况，以实测的地球物理资料与卫星重力异常等相结合，分析了该地区地壳构造和上地幔深部构造的基本特征，指出该地区中强震的形成和发生既有可能与地壳层中存在的低速带和高导层有关，还可能与更深部上地幔内部构造的背景因素有关。文中还提出了一些值得进一步探讨的问题。     

秭归盆地东缘断裂构造觅踪——再论仙女山断裂带北延过长江问题

文章在概略介绍仙女山断裂带所处的大地构造位置、展布特征、组合关系基础上,用详实的材料,逐一分析了荒口—腰店子、腰店子—将军垭、将军垭—卜庄河及尹家湾—黄垭畔、黄垭畔—贾家店长江南北两岸各段的断裂构造形迹特征、力学性质和交切关系。认为仙女山断裂带已北延过长江,并建议对断裂的应力传递方式和可能出现的史前地震进行深入研究。     

P-waveform analysis for local subduction geometry south of Puget Sound,Washington

The local subduction geometry at a site south of Puget Sound in western Washington is investigated using teleseismicP-waveforms recorded on a three-component event triggered seismograph. The data are processed using source equalization deconvolution in order to isolate locally convertedP-to-S arrivals and stacked to improve the signal-to-noise ratio. Stable arrivals in the radial component indicate an oceanic Moho within the subducted slab at a depth of about 53 km beneath the station. Observed amplitude variations with azimuth in the radial data, as well as qualitative aspects of the tangential data, are used to establish a slab dip of 16° to the southeast. Our results are compatible with previous results from a site 60 km to the west, and further confirm a substantial warp in the regional geometry of the subducted Juan de Fuca plate.     

细粒含量对冰碛土抗剪强度影响的实验研究

为研究细粒组颗粒在浸水/降雨条件下产生迁移对冰碛土抗剪强度的影响,从西藏林芝市帕隆藏布嘎隆寺沟流域内采取冰碛土样品,进行7种不同细粒（粒径小于2 mm）含量情况下的冰碛土比重和相对密度的测试,开展了不同围压下的大型饱和固结不排水三轴（CU）实验。结果表明：（1）细粒含量对干密度的影响较小,不同细粒含量的冰碛土孔隙比大致相同,细颗粒对孔隙具有改造作用,不同细粒含量会引起孔隙结构的差异,从而导致冰碛土的结构差异,最终导致抗剪强度的不同;（2）细颗粒迁移导致冰碛堤坡脚和内部一定深度细粒含量较高,达到一定的量值时,抗剪强度明显降低,冰碛堤容易发生剪切破坏;（3）细粒含量对抗剪强度参数的变化具有重要影响,从中还可以反映出冰碛土结构控制的变化：粗颗粒控制→粗细颗粒共同控制→细颗粒控制。研究结果对于评价冰碛堤的稳定性具有重要意义。     

四川盆地水热型地热资源构造成因模式

地处青藏高原东缘的四川盆地是一个群山环绕的叠合型沉积盆地,蕴含着丰富的地热资源。四川盆地具有突变型和渐变型两类盆山结构,二者的构造样式存在明显差异,对盆地及周缘的水热型地热资源分布具有明显的控制作用。通过解析盆地及周缘地质构造,明确了盆地不同构造单元的构造样式;详细对比分析已有的地热勘查案例的异同性,提出了褶皱型、单斜型和褶皱—断裂复合型等3大类水热型地热资源的构造成因模式;认为四川盆地形成与演化过程中,构造运动与水热型地热资源的形成密切相关,主要表现在：1）频繁不均匀升降运动导致构造—沉积格局分异,控制着地热储盖层岩性、组合及区域展布;2）构造抬升形成的不整合面和古岩溶作用极大改善了地热储层的孔渗物性和流体输导能力,形成了优质的碳酸盐岩孔洞型热储;3）断裂可能是地下热水的补给通道和输导系统,亦或是阻隔屏障,取决于断裂类型和断层两盘岩性配置关系;4）地下热水易于沿具走滑分量断层和张性断层进行补给和输导。

     

煤炭产业经济走势及煤炭企业对策研究

煤基固体废弃物的清洁利用是矿区生态建设亟待解决的问题,重金属的结构形态是煤基固废清洁利用的关键。以安徽淮南矿区潘一矿煤矸石、粉煤灰为研究对象,利用XRF、XRD、SEM和FTIR等微区方法对煤基固废进行表征分析,探讨其精细化学结构及重金属嵌布方式,并结合RAC(Risk Assessment Code)生态风险评价对重金属潜在风险进行评估。结果表明,煤矸石主要粒径以黏粒(0~5 μm)和粗粉砂(10~50 μm)为主,粒度不规则,空间分布间距较大,主要矿物为石英(SiO₂),IR谱线辅助验证了AlO₄和SiO₄的弯曲振动。粉煤灰粒径以粗粉砂(10~50 μm)和砂砾石(50~250 μm)为主,表面以球状包裹体和多孔颗粒组成,粒径大小不一,主要矿物相是莫来石(Al₆Si₂O₁₃),IR谱线发现其存在有机硅Si-O-Si对称伸缩和反对称伸缩。煤矸石中Ni、Pb以有机结合态和铁锰氧化物结合态为主,Cr、Cd、As的赋存形态主要是残渣态;粉煤灰中As主要以残渣态和有机结合态存在,其余重金属元素均以残渣态存在。RAC生态风险评价结果表明,煤矸石和粉煤灰中Cr、As属于低风险水平,其余重金属均无风险。研究结果对煤基固废资源化利用及矿区生态环境保护具有重要的现实意义。

     

视超光速源中3C454.3的特殊性

本文从简要总结迄今所发现的视超光速源开始。介绍近年来探测到的视超光速源之一——类星体3C 454.3的VLBI多频段,多历元观测及其主要结果。采用列表对比方式表明此源相对其他视超光速源的一般特征呈现的特殊性。最后对此特殊的视超光速源的可能解释作初步讨论。 本文可以看作是对3C453.3观测已有报导[12]和[13]的进一步补充。     

Distant field blue horizontal branch stars – III. Identification of a probable outer halo stream at Galactocentric distance r= 70 kpc

We present FOcal Reducer/low dispersion Spectrograph-1 spectra (from the European Southern Observatory's Very Large Telescope) of a sample of 34 faint  20.0 < g * < 21.1  A-type stars selected from the Sloan Digital Sky Survey Early Data Release, with the goal of measuring the velocity dispersion of blue horizontal branch (BHB) stars in the remote Galactic halo,   R ∼ 80 kpc  . We show that colour selection with  1.08 < u *− g * < 1.40  and  −0.2 < g *− r * < −0.04  minimizes contamination of the sample by less luminous blue stragglers. In classifying the stars we confine our attention to the 20 stars with spectra of signal-to-noise ratio >15 Å⁻¹. Classification produces a sample of eight BHB stars at distances  65–102 kpc  from the Sun (mean 80 kpc), which represents the most distant sample of Galactic stars with measured radial velocities. The dispersion of the measured radial component of the velocity with respect to the centre of the Galaxy is  58 ± 15 km s⁻¹  . This value is anomalously low in comparison with measured values for stars at smaller distances, as well as for satellites at similar distances. Seeking an explanation for the low measured velocity dispersion, further analysis reveals that six of the eight remote BHB stars are plausibly associated with a single orbit. Three previously known outer halo carbon stars also appear to belong to this stream. The velocity dispersion of all nine stars relative to the orbit is only  15 ± 4 km s⁻¹  . Further observations along the orbit are required to trace the full extent of this structure on the sky.     

Recognition of Paleo-Tethys Suture Zone in eastern Myanmar

The site of final closure of Paleo-Tethys Ocean during the Triassic-Jurassic was marked by the colli-sional event between the Shan Massif and Indochina plate, in eastern Myanmar. Previous site of consumption of Paleo-Tethys is now occupied by a complex zone of suturing and deformation along Than Lwin River and in the east of it, formed by drastic tectonic evolution. It is geographically located approximately between longitudes 98E and 100E, and it extends northwards to Yunnan and southwards into West Thailand. The sigmoidal wrench struc-tures of suture zone is situated in the east of step-like structures of Shan Massif, and the western boundary of the suture zone must be immediately on the west side of Than Lwin River and the eastern boundary is near the east border of Myanmar. The area is largely covered by younger rocks of Paleozoic and Mesozoic age. The Upper Pa-leozoic units of Carboniferous to Permian comprise limestone and dolomite of the Plateau Limestone overlying unconformably the Lower Paleozoic rocks. Metasedimentary rocks of the Carboniferous and their metamorphic equivalents and the flysch-like Triassic-Jurassic units are found as folded and thrusted beds in the area. Large complex of granitic rocks of Late Triassic are also found. Metavolcanics, gabbro and a large number of chromite occur along with these units. A preliminary delineation of a suture zone as the site of closure of Paleo-Tethys Ocean in Myanmar territory is made for the first time and this zone is believed to be a tectonic linkage between Changning-Menglian belt of West China and Inthanon Zone of West Thailand.     

北京平原地区地质系统

经过几代人的工作,北京平原地质工作取得了丰硕的成果,在基础地质、水文地质、工程地质和环境地质等领域都有重要进展。本文通过北京平原三维地质结构分析,认为北京平原的地下水资源、工程地质、地面沉降、地裂缝灾害等地质问题均受三维地质结构控制,各种地质现象都处在一个统一的地质系统之内。第四系三维结构控制着第四系孔隙水资源的赋存、平原的工程地质特征和地面沉降的分布和演化;基岩的三维结构控制基岩裂隙水、岩溶水资源和地热资源的赋存状态;平原隐伏断裂对平原的地貌、基底形态起控制作用,对地裂缝,地面沉降等地质灾害的形成和发展有重要影响。这些由三维地质结构控制的地下水子系统,隐伏断裂子系统以及工程地质、地面沉降等地质问题,共同组成了北京平原区地质系统。