手掘式顶管在市政排水工程中的应用

从混凝土管材的选定、工作坑的设计及施工、顶管顶进中若干关键问题入手,介绍了手掘式顶管施工技术在成都市中心城水环境综合整治工程G标段管道排水工程中的应用。     

Characteristic analysis on oxygen isotopic tracer in the East China Sea and waters to east of the Ryūkyū-guntō

Samples of O isotopic tracer were mlleMed at Sections P₃,P₂₅,P_cM-t/2-E and P_CM-1/2.w in both the Fast China Sea and the area to the east of the Ryūkyū-gunto during October-November,1991.Analytical results of the δ¹⁸O are as follows: (1) In the Kuroshio area,the δ¹⁸O isolines are almost parallel to the 200 m isobath.The value of δ¹⁸O is negative and reaches minimum mt the main axis of the Kuroshio,and increases on both sides.(2) In the Taiwan Warm Current (TWC) area there is a high δ¹⁸O tongue extending to the northeast.(3) In the area near the coast,the distribution of δ¹⁸O isoline shows that the Changjiang River runoff diffuses seaward and the land-ocean isotopic effect from the nearshore to the offshore.(4) The values of δ¹⁸O are from -1.0×10^-3 to -0.5×10^-3 in the shelf.(5) There is a low mre of δ¹⁸O value(<-1.6×10^-3) at the 600 m layer in the Kuroshio area,which is quite in accord with the existence of a low salinity mre (S G 34.30) between the 600 and 800 m layers in the same area.Finally,the mrrelations of the δ¹⁸O with the salinity and temperature,the upwelling and so on are discussed.     

Actinic flux and photolysis frequency comparison computations using the model PHOTOGT

The accurate radiative transfer model GOMETRAN, initially designed to yield radiances at TOA in the wavelength range 240–790 nm, has been extended to allow for the computation of actinic fluxes down to 175 nm and for the calculation of photolysis frequencies in the atmosphere. The capability of the extended model PHOTOGT (PHOTOGOMETRAN) is demonstrated in a number of successful comparison studies both with recent experiments (ground-based, balloonborne, airborne) and model calculations of radiances, actinic fluxes and photolysis frequencies in the stratosphere and troposphere. In an atmospheric case study, the impact of new quantum yield data for the O₃ » O₂+O(¹ d) photodissociation channel on the photolytic production of O(¹ d) atoms in the lower atmosphere has been quantified.     

Petrogenesis and tectonic setting of Cadomian felsic igneous rocks, Sandıklı area of the western Taurides, Turkey

In the Sandıklı (Afyon) region, western Taurides, the Late Proterozoic rocks of the Sandıklı basement complex are composed of low-grade meta-sedimentary rocks (Güvercinoluk Formation) intruded by felsic rocks (Kestel Cayı Porphyroid Suite, KCPS). The KCPS is a deformed and highly sheared, dome-shaped rhyolitic body with a granitic core. Quartz porphyry dikes intrude both the slightly metamorphic igneous and the sedimentary rocks of the basement complex. Both the quartz porphyries and rhyolites were converted into mylonites with relict igneous textures. Geochemical data show that these felsic igneous rocks are subalkaline and mainly granitic in composition with SiO₂ >72 wt% and Al₂O₃ >11.5 wt%. The chondrite-normalized incompatible trace element patterns are characterized by distinct negative Rb, Nb, Sr, P, Ti, and Eu with enrichment in Th, U, La, Ce, Nd, Sm, and Zr. The REE patterns of the felsic rocks indicate a strong enrichment in LREE but display slightly flat HREE patterns. According to geochemical characteristics and petrogenetic modeling, extrusive and intrusive rocks of the KCPS were probably derived from an upper continental crustal source (partial melting of granites/felsic rocks) by 18–20% fractional melting plus 18–20% Rayleigh fractional crystallization, which seems to be the most effective igneous process during the crystallization of the KCPS. Single zircon age data from the granitoids and fossils from the disconformably overlying sedimentary successions indicate that the metamorphism and the igneous event in the Taurides are related to the Cadomian orogeny. Based on the geological, geochemical and petrogenetic correlation of the post-collisional granitoids it is further suggested that the Tauride belt in western central Turkey was in a similar tectonic setting to the Gondwanan terranes in North Africa (Younger Granitoids) and southern Europe (Spain, France, Bohemia, Brno Massifs) during the Late Cadomian period.     

DMC＋4小卫星在国际灾害监测中的应用与评价

针对国际灾害监测星座应用技术和中国各种自然灾害的现状,着重研究了DMC(DisasterMonitoringConstellation)星座应用技术和DMC 4小卫星的数据特点,研究了利用小卫星星座对防灾、抗灾救灾的突出作用,研究了小卫星地面系统集成技术和星地一体化运营、管理和控制体系,以便进一步推动国内小卫星技术、遥感应用技术、卫星星座技术、天地一体化运管控技术和机制创新的发展。促进中国灾害监测星座的研制,最终实现对各种自然灾害的实时、动态监测。     

烃类垂向微渗漏及其地表异常显示

烃类以微泡、水动力、扩散和渗透方式向地表迁移过程中,其效能、方式与油气藏的盖层、断裂与裂隙系统、储层的流体性质、地层压力等地质因素密切相关.通过对塔里木盆地雅克拉凝析气田上的地表、井中化探资料与地质资料的综合分析,认为该气田的井中垂向地球化学特征、控制烃类垂向微渗漏地质因素、地表化探异常显示之间呈现出很好的内在联系.     

赣北修水观音阁砾岩特征及其构造意义

有关赣北地区双桥山群内角度不整合和地壳运动存在与否问题,一直争论不休。论文以较丰富的详细野外调查资料为基础,并结合前人研究成果和室内各类样品测试结果,围绕这个赣北地区重要的基础地质问题进行了讨论。作者认为“修水运动”不能成立,并提出了砾岩的沉积模式。     

Properties of wave velocity for two types of granitoids at high pressure and temperature and their geological meaning

The wave velocity for two types of granitoids was measured using the analytic method of full-wave vibration at high pressure and high temperature. The laws of velocity changes for them differ with the pressure boost and temperature rise, and the velocity change of S-type is more violent than that of I-type. The “softening point” of compressional wave velocity (V μ) is also revealed during the measurement for two types of granitoids imitating the pressure and temperature at a certain depth. But the depth of “softening”, V_p after “softening” and the percentage of V_p’s drop around the “sofrening point” for two types of granitoids are obviously different. The depth of “softening” is 15 km approximately and V_p after “softening” is 5.62 km/s for S-type granitoid. But for I-type granitoid the depth of “softening” is 26 km approximately and V_p after “softening” is 6. 08 km/s. Through careful analysis of rock slices after the experiment, it was found that the “softening” of elastic-wave velocity is caused by the partial melting of granite. Combined with the results of geophysical prospecting, these results suggest that the low-velocity layers developing in the interior of Earth crust are related to thc partial melting of different types of granitoids. The formation of the low-velocity layer in the upper-middle Earth crust is closely related to the development of S-type granitoid, but that in the lower Earth crust is closely related to the development of I-type granitoid.     

Petrology of the Jurassic Shah-Kuh granite (eastern Iran), with reference to tin mineralization

The Shah-Kuh granitic pluton of eastern Central Iran was emplaced 165 Ma ago, in an active continental margin setting. It is made of two main units: a granodioritic unit (SiO₂=63–71 wt%) to the north–west and a syenogranitic unit (SiO₂=73–77 wt%) to the south–east. The former unit displays seriate medium-grained textures and contains locally abundant mafic enclaves. The latter unit is medium- to coarse-grained and porphyritic, with 0.5–3 cm long K-feldspar megacrysts. Fine-grained granitic bodies are present in both units. The rocks are metaluminous to slightly peraluminous (I-type) and peraluminous (S-type) and belong to the ilmenite-series granites. Fractional crystallization appears to have been a very effective differentiation process in both units, and the fractionated mineral assemblages are determined by mass balance calculations. Isotopic data (Sr_i=0.7065 and εNdt=−2.5) are consistent with a young upper crustal protolith. Tin mineralization in sheeted quartz-tourmaline (-cassiterite) veins is spatially associated with the granodioritic unit. The veins formed by hydraulic fracturing when the granodioritic to monzogranitic magma became water-saturated and exsolved a fluid phase during crystallization. The reduced nature of this magma is responsible for the incompatible behaviour of Sn, likely to favour Sn concentration in the residual melt and then in the exsolved fluid. Another fluid phase was exsolved by the syenogranitic magma and was responsible for local greisenized granites, characterized by high Y and HREE-contents and non-fractionated REE distribution patterns. Field and mineralogical data show that the (B, Sn) vein-forming fluid was different from the (F, Li) greisen-forming fluid.     

伊犁盆地南缘中新生代构造样式与铀成矿关系

伊犁盆地是我国最早发现砂岩型铀矿的地区,近十几年来一直保持砂岩型铀矿找矿的不断突破,盆地南缘自西向东查明了一系列砂岩型铀矿床,这些铀矿床的分布与盆地南缘构造关系密切。本文总结了伊犁盆地南缘构造样式类型,分析了不同构造样式下氧化流体补给、运移规律,并结合铀矿体的空间分布,指出构造样式差异是造成砂岩型铀矿体空间分布的关键因素;从氧化流体补给窗的开启、流体的汇聚和还原性气体聚集的控制等方面讨论了构造样式对铀矿体空间定位的机制,指出单斜稳定地层中纵弯背斜是控制铀空间分布的主要构造,要注意不同构造样式约束下成矿区域的稳定型和地下水补给的多样性,在此基础上讨论了伊犁盆地南缘铀矿的找矿方向及主要矿物类型。