断层滑动对邻近场的影响

对含一组裂纹的平板模型的有限元计算表明,在断层滑动后,其附近应力场发生了较大变化,有的应力场方向几乎偏转了90°。这可能是震前P轴偏转的一种力学机制。当把裂纹间的关系类比为一组断层时,计算结果表明,断层的滑动将影响附近断层,使有的断层滑动的可能性增大,而有的断层滑动的可能性减小,即对有的断层起了“加震”作用,而对有的起了“减震”作用。由此看出,成组发生的地震间表现出“自序性”。依此自序特点对华北第三、四活动期中地震幕作了划分,结果与其它研究所划分的一致。因此,本项研究也是对地震幕物理涵义的一种探讨。     

产于我国广东省的沃奇纳矿

本文的Wodginite产于广东某富钽花岗伟晶岩中,呈不规则粒状,棕红色。文中对该矿物作了探针分析、X射线粉晶衍射,并与国外的同种矿物作了对比,从空间群结构式和阳离子有序式探讨了该矿物译名的新意见。     

测井曲线的岭回归及岩性柱状图的自动拾取

本文介绍了地球物理勘探测井资料的计算机处理中,采用岭回归方法对测井曲线DLW、HG、HGG、DZW进行处理,直接生成岩性柱状图。简要介绍了岭回归的原理和方法并通过实例,经过样本训练,给出了岩性的预测公式,计算结果和计算机绘制的岩性柱状图。该方法的实现对测井资料的计算机解释和成图有较大现实意义。     

Stable Strontium Isotopic Fractionation During Chemical Weathering in Drainage Basins: Mechanisms and Applications

The new non-traditional stable strontium (Sr) isotope has aroused great attention from academic scholars in terms of the continental weathering and marine Sr cycle. The analytical precision of stable Sr isotope using mass spectrometry is better than 0.03‰. The compiled δ⁸⁸/ ⁸⁶Sr values vary from -3.65‰ to 1.68‰ in natural reservoirs. Recent findings indicate that multiple processes can cause stable Sr isotope fractionation in Earth surface, including the incongruent dissolution of primary minerals, the formation and adsorption of secondary minerals, the precipitation of calcium carbonate, and the biological cycling. These processes lead to higher δ⁸⁸/ ⁸⁶Sr in the liquid phase and lower δ⁸⁸/ ⁸⁶Sr in the solid phase, and thus result in different geochemical behavior of stable Sr isotopes in water and sediment during the weathering processes. The δ⁸⁸/ ⁸⁶Sr values of river sediment decrease with the increase of weathering intensity, which has the potential to indicate chemical weathering intensity. Meanwhile, further study on the fractionation mechanisms and constraints of stable Sr isotopes in river water plays an important role in tracing chemical weathering processes within the watershed, which will lead to a better understanding of the global ocean Sr cycle.     

Electrogeochemical extraction technique in the prospecting of buried gold deposits

A new electrogeochemical extraction technique has been used in cooperation with the field paper chromatographic method to determine gold which migrates in ionic form and is deposited on the electrode inserted in the soil. The technique has been tested with encouraging results in several Au areas. The results indicate that distinct Au anomalies can be discovered which have been buried by transported overburden.     

海南岛兰洋地区石炭系孢子的发现及其意义

笔者等在海南岛兰洋地区发现了丰富的石炭系孢子,计３８属６４种。其中,产于青天峡组上部的孢子组合,与Ｇ．Ｃｌａｙｔｏｎ等人所建立的“ＰＵ“带相当,属韦宪期早期。产于石岭组下部的孢子组合,则具有韦宪期中晚期的色彩。这些孢子的发现,为该区石炭系的划分与对比提供了重要依据,同时也有助于探讨海南岛大地构造的某些问题。作者依据孢子组合及其伴生的植物化石,对石炭纪广东大陆与海南岛分属两个地体的看法提出了质疑,而     

A garnet-cordierite granite porphyry containing rapakivi feldspars in the Cabeza de Araya batholith (extremadura,spanish Hercynian belt)

Summary The garnet-cordierite granite porphyry is a large dyke associated with the Cabeza Araya batholith. The batholith shows S typology but with intermediate characteristics between the aluminous granite series, spatially and genetically related to the Hercynian regional metamorphism, and the calc-alkaline series of the Iberian massif. The granite porphyry is rich in megacrystic alkali feldspar often with rapakivi texture. Its mineralogy consists mainly of quartz + plagioclase + alkali feldspar + biotite I + cordierite I + garnet + biotite 11 + cordierite II ± muscovite + chlorite.Cordierite-garnet thermobarometry and stability relationships of ternary feldspars are used to estimate the T-P conditions of crystallization and the evolution of these rocks. The equilibrium temperature obtained from the cordierite-garnet pair is about 800°C (4 ± 0.5 Kb). This shows the xenocrystic origin of cordierite and garnet, in accordance with other geological and textural evidence. Garnet transformation, the genesis of Cordierite II and the formation of mantled textures are interpreted as the result of an isothermal decompression accompanying the emplacement of the porphyry.

---

Eine Rapakivi-Feldspat führender Granat-Codierit-Granitporphyr aus dem Cabeza de Araya Batholith (Extremadura, Hereynischer Gürtel, Spanien)

Zusammenfassung Der Granat-Cordierit-Granit stellt einen mit dem Cabeza Araya Batholith assoziierten, mächtigen Gang dar. Der Batholith zeigt S-Typ Charakter, jedoch mit bergangsmerkmalen zu aluminösen Granitserien, und steht räumlich und genetisch im Zusammenhang mit der hercynischen Regionalmetamorphose und den Kalkalkaliserien des iberischen Massivs. Der Granitporphyr führt häufig Megakristalle von Alkalifeldspat, die oft Rapakivitextur zeigen. Die Mineralogie des Granitporphyr besteht aus Quarz + Plagioklas + Alkalifeldspat + Biotit 1 + Cordierit 1 + Granat + Biotit II + Cordierit II ± Muscovit ± Chlorit. Die P-T Bedingungen der Kristallisation und die magmatische Entwicklung dieserDie wurde, P-T Bedingungen der Kristallisation und die magmatische Entwicklung dieser Gesteine wurde, unter Anwendung der Cordierit-Granat Thermobarometrie und den Stabilitätsbeziehungen der Feldspäte, ermittelt. Die Gleichgewichtstemperatur aus Cordierit-Granat-Paaren beträgt um 800°C (4 ± 0.5 Kb). Dies zeigt die Bildung von Cordierit und Granat als Xenokristalle, in Übereinstimmung mit anderen geologischen und texturellen Merkmalen. Die Transformation des Granat. die Genese von Cordierit II und das Entstehen von mantled Texturen, kann als Resultat einer isothermalen Dekompression interpretiert werden, die die Platznahme des Porphyrs begleitet hat.

---

---

With 5 Figures     

A global experimental model for gravity tides of the Earth

The long-term, continuous and high-quality tidal gravity data, recorded with the superconducting gravimeters (SGs) at 19 stations in the Global Geodynamics Project (GGP), were simultaneously used to investigate the global pattern of the tidal gravity variations. The atmospheric effects were removed from the gravity observations by using the simultaneous pressure records at the stations. A total of six global co-tidal models were employed to remove the loading effects of oceanic tides. The resonance parameters of the Earth's free core nutation (FCN), as well as the spheroidal constant components in the gravimetric factors of waves O₁ and M₂, were accurately retrieved. As a result, a global experimental model for gravity tides (GEMGT) was developed, considering the nearly diurnal resonance and the latitude-dependence of the gravimetric amplitude factors. The final results indicate that the mean discrepancy of the four main tidal waves (i.e. O₁, K₁, M₂ and S₂) between the GEMGT and SG observations is less than 0.2% on average. The GEMGT is in good agreement with the theoretical models based on the inelastic non-hydrostatic equilibrium Earth models [Dehant, V., Defraigne, P., Wahr, J., 1999. Tides for a convective Earth. J. Geophys. Res. 104, 1035–1058; Mathews, P.M., 2001. Love numbers and gravimetric factor for diurnal tides. J. Geodetic Soc. Jpn. 46 (4), 231–236] with a mean discrepancy less than 0.15%. However, the GEMGT is in closer accordance with the theoretical model given by Mathews [Mathews, P.M., 2001. Love numbers and gravimetric factor for diurnal tides. J. Geodetic Soc. Jpn. 46 (4), 231–236] for the diurnal tides while it is in closer agreement with one obtained by Dehant et al. [Dehant, V., Defraigne, P., Wahr, J., 1999. Tides for a convective Earth. J. Geophys. Res. 104, 1035–1058] for the semi-diurnal tides.     

模式顶选取对南海季风爆发过程模拟的影响

本文利用MM5(V3)中尺度模式系统以1998年5月南海季风爆发过程为例，试验了模式顶层气压选取对南海季风爆发过程模拟结果的影响。共做了2个数值试验，分别将模式项选在100hPa和50hPa。试验表明，模式顶选取更高将使得和南海季风爆发过程相对应的东亚高空急流强度和位置模拟与观测更趋一致，并且南海北部地区季风爆发后强降水发生的时间及降水强度的模拟也得到明显改善。     

Fluid flow and mineralization of Youjiang Basin in the Yunnan-Guizhou-Guangxi area,China

Comprehensive studies, based on isotope geochemistry of C, H, O, S and Sr, chronology, common element and trace element geochemistry of fluid inclusions for the epithermal Au, As, Sb and Hg deposits in the Youjiang Basin and its peripheral areas, suggested that the ore fluid was the basin fluid with abundant metallic elements and the large-scale fluid flow of the same source in the late Yenshan stage was responsible for huge epithermal mineralization and silicification. The ore fluid flowed from the basin to the platform between the basin and the platform and migrated from the inter-platform basin to the isolated platform in the Youjiang Basin. The synsedimentary faults and paleokast surface acted respectively as main conduits for vertical and lateral fluid flow.