稳定同位素在准噶尔盆地西北缘层间氧化带砂岩型铀矿预测中的应用

本文运用稳定同位素研究方法[1],探讨解决常规放射性水化学调查分析中难于解决或难于解释的若干问题。从而为准确地确定准噶尔盆地西北缘地区是否存在层间氧化带提供新的依据,达到预测铀成矿远景的目的。     

多点入流汇流计算法在北京城市洪水计算中的应用与研究

根据北京城市化水平,城市汇流特点,通过用多点入流汇流计算法模拟实测洪水过程线,分析了北京城市河道的汇流特点与规律,初步提出了一种适合于北京城市洪水计算的方法,为城市防洪排水工程规划,设计提供依据。     

湘赣边地区走滑断裂带致矿异常的结构样式及分形特征

湘赣边地区构造岩浆带是环太平洋成矿带内最重要的高值地质矿产异常区,其中ＮＮＥ向走滑断裂明显地控制了岩浆－断陷盆地和铀及钨、锡、铅、锌、锑等的成矿作用．在区域地质环境研究的基础上,根据典型矿田（床）控矿构造分析成果,将走滑断裂带内局部性致矿地质异常归纳为：帚尾式致矿异常,棋盘格式致矿异常、辫状结环式致矿异常和拉分盆缘式致矿异常．重点讨论了各类异常的结构样式和分维特点．     

寿昌—临浦火山岩带赋矿流纹岩特征及归属雏议

本文介绍的火山岩带,有层状流纹岩及穹丘状、岩颈状等非层状流纹岩,分别属溢流相、侵出相及火山管道相,三种流纹岩均受火山岩带核中断裂及晚期火山构造控制,复盖或穿发寿昌组一段地层,又被寿昌组一段之后的次火山岩及隐爆岩所穿切,局部被横山组不整合复盖。该类流纺岩同位素年龄值较小,多数在１３０Ｍａ左右,处于晚侏罗世与早白垩世过渡期。根据其层序、穿切关系及同位素年龄等,认为三种流纹岩均属火山岩带晚期不同岩相的产     

火山活动与沉积盆地的形成和演化

我国大陆地壳进入中生代以来,发生了较其他陆壳更为强烈的构造运动,印支,燕山,喜马拉雅运动都是发生在我国大陆地壳以裂陷作用为主的典型运动,在中生代板块构造的特定时代和以裂陷作用主主的构造运动作用下,岩浆活动沿断穿骨石圈和地壳的深断裂发生,上涌至地壳地面形成火山岩带和地层格架中的火山岩层,上涌至地壳内部形成壳内流体相央浆房而成为高导层,火山活动是由中生代生成的太平洋板块和我国大陆地壳俯冲,使大陆地壳深     

韧性剪切过程中金沉淀富集的新机制

一般认为,金的沉淀是因为成矿热液在宏观上已达到金络合物失稳、分解的条件。笔者认为金在黄铁矿、毒砂等硫化物矿物中富集的原因,是这些矿物生长时造成了在其生长面附近的微区内会出现Ｅｈ值及（或）Ｓ＾２－、［ＡｓＳ］＾３－等浓度的局部降低,以致引起了金络合物在此微区内的失稳、分解,分解出来的金将就近附着在矿物的生长面上及随后被包围。成矿热液此时在宏观上不一定已达到金络合物的分解条件。韧性剪切过程中石英普遍会     

一个韧性转换挤压带的变形分解作用：以阿尔金断裂带东段为例

变形构造研究显示阿尔金划分成具有近水平拉伸线理的韧性左行走滑变形域和具有陡角度倾伏拉伸线理的收缩变形域。在ＳＳ与ＰＳ之间的过渡区域还发现中等角度倾伏的拉伸线理。     

Geochemical engineering; taking stock

Geochemical engineering makes use of optimized geochemical processes for the solution of environmental problems. It has developed in a few years from a collection of unrelated scientific and technological incidents into a coherent concept about how and where we can improve our geo-environment. All solutions to problems of pollution are based on neutralization/breakdown, concentration, dilution, isolation or immobilization, which serve to eliminate the pollutant, make it more manageable, or prevent its entry into the mobile phase, usually water, from which it can affect the biosphere. All of these solutions have their counterpart in nature, where many examples are found of high concentrations of potentially harmful substances. A major prerequisite of geochemical engineering solutions is that they should be compatible with the natural evolution of the system in its geo-environment. The advantages of this approach are that we can devise low-cost technologies (nature does most of the hard work itself), interfere least with nature, and quite often end up with useful by-products. Disadvantages are that technologies based on natural geochemical processes tend to be slow. The application of geochemical engineering concepts requires a better understanding of our environment and its ongoing processes than is necessary for a ‘classical' technology. In most environmental technologies the conditions are externally imposed on the system to be treated, and the natural evolution of the system is eliminated, or at best neglected. The concept of seeking a closer conformity with nature is paralleled in other disciplines like agriculture or the medical sector, where we see a similar evolution in the direction of techniques that are more in harmony with nature. Geochemical engineering brings many advantages, particularly in developing countries, or in countries where the state of the economy does not permit the introduction of expensive high-tech environmental technologies. So far, most of the applications of geochemical engineering concepts have focussed on solutions to environmental problems, but there are a number of cases where the environmental issue is more indirect, as e.g. in civil engineering. Geochemical engineering may be practised on a large, almost global scale, down to that of individual minerals, in accordance with the fact that geochemical processes also act on vastly different scales. An overview will be given of some of the problems that are being studied.     

贵州天柱磨山—油麻坳金矿化带岩石矿物地球化学研究

研究了贵州天柱磨山—油麻坳金矿化带的成矿条件、控矿规律及地球化学特征。认为：金元素来源于地层;成矿流体具变质水和大气降水混合特征;褶皱翼部与断裂交汇带及层间破碎带等控制着矿体产出。成矿作用过程具沉积变质改造作用特点,多期次的构造变质作用对金元素的迁移聚集有着重要控制作用。     

Thickness estimates of the upper-mantle transition zone from bootstrapped velocity spectrum stacks of receiver functions

We modify the receiver-functions stacking technique known as velocity spectrum stacking (VSS) so as to estimate combinations of velocity model ( V_P and V_S ) and depth that stack the Ps conversion from upper-mantle discontinuities most coherently. We find that by estimating the differences in the depths to the 660 and 410 km discontinuities using velocities that maximize the stacked amplitudes of P410s and P660s phases we can estimate the thickness of the transition zone more accurately than the depths to either of these discontinuities. We present two examples indicating that the transition zone beneath Obninsk, Russia, is 252±6 km thick and that beneath Pasadena, California, is only 220±6 km thick.