西藏一江两河地区高精度航磁勘查效果

中国国土资源航空物探遥感中心于2000-2001年在西藏一江(雅鲁藏布江)两河(拉萨河、年楚河)地区开展了1:20万～1:25万高精度航磁勘查,发现一批具有找矿意义的异常、一组北西向断裂及其他构造形迹,为基础地质研究、1:25万区域地质调查和矿产资源勘查评价提供了高精度的地球物理资料.     

西藏当惹雍错晚侏罗世-早白垩世扎列拿组、郎穷组和荣纳组的建立

通过1:25万邦多区幅地质调查,发现晚侏罗世-早白垩世则弄群中存在2个喷发-沉积不整合界面,将则弄群自然分成3个部分,对应3个火山喷发-沉积旋回.新创建扎列拿组、郎穷组和荣纳组.描述了3个组的定义及层型、次层型的岩性、岩相、古生物、同位素年代特征及其分布情况.     

Geological outline of the Alps

The Alps were developed from the Cretaceous onwards by subduction of a Mesozoic ocean and collision between the Adriatic (Austroalpine-Southalpine) and European (Penninic-Helvetic) continental margins.The Austroalpine-Penninic wedge is the core of the collisional belt, a fossil subduction complex which floats on the European lower plate. It consists of continental and minor oceanic nappes and is marked by a blueschist-to-eclogite-facies imprint of Cretaceous-Eocene age, followed by a Barrovian overprint. The collisional wedge was later accreted by the Helvetic basement and cover units and indented by the Southalpine lithosphere, which in turn was deformed as an antithetic fold-and-thrust belt.     

闪长岩强风化带做高层建筑天然地基的可行性研究

借助于中国工商银行山东省分行营业办公楼的工程实践,将常规勘察与原位测试相结合,运用野外钻探、室内试验、原位测试多种手段,对闪长岩强风化带的物理力学性质进行了测试分析和深入地研究,并通过对承载力、沉降变形的验算,得出其作为高层建筑的天然地基是可行的。实践证明,与桩基础处理方案相比,节省资金近200万元,大大加快了施工进度,减少了基础施工难度,取得了巨大的经济效益与社会效益;同时,也提出了研究岩石风化带所遇到的问题:由于采取原状试样及制样难,导致对其物理力学性质了解不够。     

中国大陆现今构造应力场的回归分析研究

叙述了应用有限元方法和回归分析理论,依据实际应力观测资料,结合中国大陆构造地质资料反演中国大陆现今构造应力场的研究成果。计算中考虑了地壳结构在纵向上和横向上的非均匀性和现今活动断层的影响,采用接触分析方法模拟了板块边界的作用。计算结果表明,通过回归分析得到中国大陆现今构造应力场特征与实际观测结果是一致的:(1) 在中国大陆现今水平最大主压应力轴走向以青藏高原为中心,呈辐射状分布;(2) 在中国大陆现今水平最大主压应力总体表现为由西向东逐渐降低的趋势;(3) 中国大陆东南的台湾海峡区域水平最大主压应力有局部升高的现象。     

Regional Fault Systems of Qaidam Basin and Adjacent Orogenic Belts

The purpose of this paper is to analyze the regional fault systems of Qaidam basin and ad-jacent orogenic belts. Field investigation and seismic interpretation indicate that five regional fault sys-tans occurred in the Qaidam and adjacent nment.qin belts, controlling the development and evolution of the Qaidam basin. These fault systems are: (1)north Qaidam-Qilian Mountain fault system; (2) south Qaidam-East Kunhm Mountain fault system;（3）Altun strike-slip fault system; (4) Elashan strike-slip fault system, and (5) Gansen-Xiaochaidan fault system. It is indicated that the fault systems controlled the orientation of the Qaidam basin, the formation and distribution of secondary faults within the basin,the migration of depocenters and the distribution of hydrocarbon accmnulation belt.     

Theoretical Study on Stochastic Modeling of Combined Gravity-Magnetic-Electric-Seismic Inversion and Its Application

As gravity field,magnetic field,electric field and seismic wave field are all physical fields,their object function,reverse function and compound function are certainly infinite contiuously differentiable func-tions which can be expanded into Taylor (Fourier) series within domain of definition and be further reduced in-to solving stochastic distribution function of series and statistic inference of optimal approximation,This is the basis of combined gravity-magnetic-electric-seismic inversion built on the basis of separation of field and source gravity-magnetic difference-value(D-value)trend surface,taking distribution-independent fault sys-tem as its unit,depths of seismic and electric interfaces of interests as its corresponding bivariate compound re-verse function of gravity-magnetic anomalies and using high order polynomial(high order trigonometric func-tion)approximating to its series distribution,The difference from current dominant inversion techniques is that,first,it does not respectively create gravity-seismic,magnetic-seismic deterministic inversion model from theoretical model,but combines gravity-magnetic-electric-seismic stochastic inversion model from stochastic model;second,after the concept of equivalent geological body being introduced,using feature of independent variable of gravity-magnetic field functions,taking density and susceptibility related to gravity-magnetic func-tion as default parameters of model,the deterministic model is established owing to better solution to the con-tradictioc of difficulty in identifying strata and less test analytical data for density and susceptibility in newly explored area;third,under assumption of independent parent distribution,a real modeling by strata,the prob-lem of difficult plane closure arising in profile modeling is avoided,This technology has richer and more detailed fault and strata information than sparse pattern seismic data in newly explored area,successfully inverses and plots structural map of Indosinian discontinuty in Hefei basin with combined gravity-magnetic-electric-seismic inversion,With development of high precision gravity-magnetic and overall geophysical technology,it is certain for introducing new methods of stochastic modeling and computational intelligence and promoting the develop-ment of combined gravity-magnetic-electric-seismic inversion to open a new substantial and promoting the develop-ment of combined gravity-magnetic-electric-seismic inversion to open a new substantial path.     

ENSO事件中纬向异常流反向与东西侧边界反射的联系

建立一个中等复杂程度的海-气耦合模式研究东、西边界反射,纬向平流项-u′(δ)(T+T′)/(δ)x在ENSO循环位相转换中的作用及东、西边界反射与纬向异常流(u′) 符号改变的关系.结果得到:u′超前Nio3区SSTA位相转变的原因是东、西边界反射造成的.Sverdrup 平衡时所产生的地转流(ur)与东、西边界反射所产生的地转流(ur)的方向在大部分时间里是相反的,同时ur与风应力强迫之间大约有9个月的滞后时间(Kelvin波从180°E出发经东边界反射产生的Rossby波到达180°E时间).在模式ENSO事件消亡过程中的某一时刻以后,边界反射产生的调整过程变为主要过程,u′主要由ur来决定,这样就造成了u′的反向先于Nio区SSTA的反向.它实际上是海洋的调整过程与风应力强迫之间滞后关系的一种反映.敏感性数值试验表明,取消东边界反射,耦合模式能够模拟ENSO循环,但其周期比控制试验的周期短一年(3年).取消-u′(δ)(T+T′)/(δ)x,耦合模式能够模拟ENSO循环,但其周期比控制试验的周期长2年(6年).     

气温前冷后暖降水分布不均

2003年5～6月,新疆主要天气气候特点是:冷暖交替,前冷后暖。5月份全疆大部地区气温略偏低,而6月份全疆大部地区气温偏高;降水量,时空分布不均匀,5月份北疆分布不均,而南疆大部偏多;6月份,全疆大部地区偏少,降水主要集中在北疆西部以及北疆沿天山一带的部分地区和南疆西部以及哈密地区等地;5月1～6日的低温连阴雨天气过程和局地的暴雨洪水和冰雹、大风等灾害性天气使农业生产遭受一定损失。1500hPa月平均环流形势特征从5月份500hPa月平均环流图看,极涡强中心偏向东半球,并维持稳定,中高纬呈2+4波型,大西洋沿岸到北欧为平均低槽活动区,西西伯…     

山东省龙卷风发生的气候特征

根据藤田-皮尔森强度分类法对1950年～2000年山东省出现的351次龙卷风进行分类，其中F0级61次，F1级256次，F2级34次。山东半岛、鲁中、鲁南出现次数较多，鲁西北较少。1950～1972年发生次数明显高于1973～2000年。龙卷风发生存在明显的季节变化，夏季发生较多。龙卷风主要发生于午后至傍晚，多数龙卷风仅能维持几分到十几分钟。