鲁北和鲁西南地区古近纪盆地沉积特征与控制因素探讨

鲁北地区和鲁西南地区古近纪盆地在地层、沉积和构造演化上都具有可对比性。鲁西南露头区古近纪地层及其沉积特征的研究对鲁北覆盖区古近纪古环境的恢复和沉积特征研究起到重要的参考作用。本文对两个地区的地层和沉积特征进行了对比。根据官庄群在鲁西南地区的沉积分布，发现了在晚白垩世至早始新世鲁西南盆地发生时间有从南向北、由东向西推迟的规律。通过对鲁西南和济阳塌陷沉积和断层发育特征的对比研究发现，郯庐断裂在晚侏罗世至早始新世以左旋剪切活动为主，派生了鲁西南和济阳塌陷NW向的断层；早始新世末期是一个构造转型期，鲁西南和济阳塌陷发育了近EW向的断层；中、晚始新世是郯庐砌裂右旋剪切活动员强烈的时期，鲁西南和济阳塌陷发育了NE向断层。     

东昆仑与西昆仑地质构造对比研究之刍议

初步总结了昆仑造山带地质构造的四大特点和东、西昆仑地质对比的三大线索，重新厘定了构造单元，并进行了对比。提出了昆仑造山带研究的重要意义及研究的基本思路。指出昆仑造山带是在老的加里东造山带基础上重新解体裂妥为洋又拼合的地带，是一个原、古特提斯洋陆转换的转换承接地带。昆仑造山带保存了从原特提斯洋消亡后，由碰撞造山到山脉老化再次裂解这一大陆构造演化阶段的许多信息，可能是我们认识中国大陆乃至欧亚大陆如何通过这种转换实现洋陆转换，把各个陆声拼接在一起的一个重要窗口。对昆仑造山带的解剖对现今仍处于碰撞后发展阶段的青藏高原的研究及今后的找矿都具有指导意义。     

Elasticity of pyrope and majorite-pyrope solid solutions to high temperatures

Majorite-garnet solid solutions are major mineral phases in the Earth’s upper mantle and transition zone. Here we present the first Brillouin scattering measurements of the elasticity of majorite (Mj, Mg₄Si₄O₁₂)-pyrope (Py, Mg₃Al₂Si₃O₁₂) solid solutions (Mj₅₀Py₅₀ and Mj₈₀Py₂₀) and single-crystal elasticity of pure synthetic pyrope at temperatures up to 800°C. The temperature derivatives of the adiabatic bulk (K_S) and shear (μ) moduli for all compositions along the Mj-Py join are the same within the experimental uncertainties (−∂K_S/∂T=14.0-14.5(20) MPa/K, −∂μ/∂T=8.3-9.2(10) MPa/K). The temperature dependence of the acoustic velocities for Mj-Py solid solutions is about half that of other major transition zone minerals. This implies that temperature variations in the transition zone, inferred from lateral velocity heterogeneity, can be significantly underestimated if the properties of majoritic garnet are not taken into account.     

Garnet-ilmenite-perovskite transitions in the system Mg4Si4O12-Mg3Al2Si3O12 at high pressures and high temperatures: phase equilibria, calorimetry and implications for mantle structure

Phase relations in the system Mg₄Si₄O₁₂-Mg₃Al₂Si₃O₁₂ were examined at pressures of 19-27 GPa and relatively low temperatures of 800-1000 °C using a multianvil apparatus to clarify phase transitions of pyroxene-garnet assemblages in the mantle. Both of glass and crystalline starting materials were used for the experiments. At 1000 °C, garnet solid solution (s.s.) transforms to aluminous ilmenite s.s. at 20-26 GPa which is stable in the whole compositional range in the system. In Mg₄Si₄O₁₂-rich composition, ilmenite s.s. transforms to a single-phase aluminous perovskite s.s., while Mg₃Al₂Si₃O₁₂-rich ilmenite s.s. dissociates into perovskite s.s. and corundum s.s. These newly determined phase relations at 1000 °C supersede preliminary phase relations determined at about 900 °C in the previous study. The phase relations at 1000 °C are quite different from those reported previously at 1600 °C where garnet s.s. transforms directly to perovskite s.s. and ilmenite is stable only very close to Mg₄Si₄O₁₂. The stability field of Mg₃Al₂Si₃O₁₂ ilmenite was determined at 800-1000 °C and 25-27 GPa by reversed phase boundaries. In ilmenite s.s., the a-axis slightly increases but the c-axis and molar volume decrease substantially with increasing Al₂O₃ content. Enthalpies of ilmenite s.s. were measured by differential drop-solution calorimetry method using a high-temperature calorimeter. The excess enthalpy of mixing of ilmenite s.s. was almost zero within the errors. The measured enthalpies of garnet-ilmenite and ilmenite-perovskite transitions at 298 K were 105.2±10.4 and 168.6±8.2 kJ/mol, respectively, for Mg₄Si₄O₁₂, and 150.2±15.9 and 98.7±27.3 kJ/mol, respectively, for Mg₃Al₂Si₃O₁₂. Thermodynamic calculations using these data give rise to phase relations in the system Mg₄Si₄O₁₂-Mg₃Al₂Si₃O₁₂ at 1000 and 1600 °C that are generally consistent with those determined experimentally, and confirm that the single-phase field of ilmenite expands from Mg₄Si₄O₁₂ to Mg₃Al₂Si₃O₁₂ with decreasing temperature. The earlier mentioned phase relations in the simplified system as well as those in the Mg₂SiO₄-Fe₂SiO₄ system are applied to estimate mineral proportions in pyrolite as a function of depth along two different geotherms: one is a horizontally-averaged temperature distribution in a normal mantle, and the other being 600 °C lower than the former as a possible representative geotherm in subducting slabs. Based on the previously described estimated mineral proportions versus depth along the two geotherms, density and compressional and shear wave velocities are calculated as functions of depth, using available mineral physics data. Along a normal mantle geotherm, jumps of density and velocities at about 660 km corresponding to the post-spinel transition are followed by steep gradients due to the garnet-perovskite transition between 660 and 710 km. In contrast, along a low-temperature geotherm, the first steep gradients of density and velocities are due to the garnet-ilmenite transition between 610 and 690 km. This is followed by abrupt jumps at about 690 km for the post-spinel transition, and steep gradients between 700 and 740 km that correspond to the ilmenite-perovskite transition. In the latter profile along the low-temperature geotherm, density and velocity increases for garnet-ilmenite and ilmenite-perovskite transitions are similar in magnitude to those for the post-spinel transition. The likely presence of ilmenite in cooler regions of subducting slabs is suggested by the fact that the calculated velocity profiles along the low-temperature geotherm are compatible with recent seismic observations indicating three discontinuities or steep velocity gradients at around 600-750 km depth in the regions of subducting slabs.     

季节转换期间副热带高压带形态变异及其机制的研究Ⅱ:亚洲季风区季节转换指数

在“季节转换期间副热带高压带形态变异及其机制的研究Ⅰ :副热带高压结构气候学特征研究”的基础上 ,进一步讨论亚洲夏季风爆发与当地对流层中上层东西向暖脊的经向位置变化关系。亚洲夏季风相继在孟加拉湾、南海和南亚爆发期间 ,除了对流层高、低空风场及深对流活动在季风爆发前后具有反相的变化以外 ,副热带高压脊面附近大气经向温度梯度亦具有明显的反相特征。对流层中上层 (2 0 0～ 5 0 0hPa)脊面附近建立的北暖南冷的温度结构 ,能够反映亚洲各季风区夏季风爆发共同的本质特征 ,根据季节转换的热力学基础 ,指出对流层中上层经向温度梯度作为度量季风爆发的指标是合理可行的。文中提出了以副热带高压脊面附近对流层中上层大气经向温度梯度作为表征季节转换的指数 ,给出了确定季节转换开始日期的具体定义以及历年季节转换日期序列 ,同时给出由85 0hPa纬向风和OLR表征的季风爆发日期序列。相关分析表明 ,85 0hPa纬向风只是个区域性指标 ,而南北温度梯度具有一定的普适性     

The accurate location of the injection-induced microearthquakes in German Continental Deep Drilling Program

Introduction The scientific drilling belongs to the International Lithosphere Program and is one of the four lithospheres explorations. So far there are more than ten countries, which have taken the scientific drilling. The German Continental Deep Drilling Program was later than the others and is the sec-ond deep drilling, but is the most significant scientific super deep drilling in the world. The Ger-man Continental Deep Drilling Program (Kontinentales Tiefbohrprogram der Bundesrepub…     

MODEL STUDY OF THE EFFECT OF SOIL NO EMISSIONS ON SURFACE OZONE*

The effect of soil NO emissions on surface ozone in autumn in East China has been studied by using TCTM(Troposphere Chemical Transport Model)with the input of meteorological variables from RAMS.The chemical mechanism for ozone variation caused by soil emissions has also been investigated.The model results reveal that soil NO emissions are important to regional ozone formation and distribution and the effect of soil NO emissions shows spatial inhomogeneity.Ozone over most areas in northern China decreases with maximum average decrement reaching 5 ppb while it increases over most areas of central and southern China with maximum average increment reaching 7 ppb caused by soil NO emissions.This situation of ozone variation is mainly determined by nonlinear photochemical mechanism.For the low NOx areas(≤3 ppb),ozone increases as NOx increases;for the high NOx areas(>3 ppb),ozone decreases as NOx increases.The effect of soil NO emissions on ozone depends on the transition value and NOx concentrations.     

粉喷桩复合地基的数值计算分析

结合粉喷桩复合地基的特点，提出采用过渡层模拟桩接触面的思路，进行了轴对称Biot固结有限元计算分析。与实测资料对比表明，可较好地揭示粉喷桩复合地基的荷载传递规律和沉降变形特性。通过对加固区和下卧层的应力计算分析，揭示了粉喷桩复合地基的附加应力场的分布特性，说明所采用的计算方法是合理可行的。