青海鄂拉山地区水系沉积物地球化学特征及找矿方向

为了研究青海省鄂拉山地区找矿远景,基于该区最新一轮1∶5万水系沉积物测量数据,提炼分析其地球化学特征之元素分布特征、元素组合特征、元素异常特征,认为该区主要成矿元素为W,Sn,Mo,Bi,Ag,Cu,Pb,Zn,Au,Sb;并指出该类成矿元素多在元古宙和古生代的地层中明显富集;主要成矿类型为矽卡岩型和热液充填型。结合已知成矿地质条件,最终优选出4个找矿远景区,为该区域提供了较明确的找矿方向。     

东海陆坡海底块体运动地形分析方法

随着油气资源开发向深水区发展,迫切需要采用一定的方法去了解块体运动的特征以及分析块体运动对深水油气资源开发的可能性.本文阐述了东海陆坡块体运动地形分析方法以及多种数据处理技术的使用.多波束测深系统为人们提供了直观的海底地貌形态特征,地层剖面仪系统能探测海底以下沉积物性质和结构的变化.GIS、Fledermaus、Delph等软件系统可以定量分析海底微地貌形态特征.     

中国夏季降水异常分布的非线性特征

运用基于前馈型人工神经网络的非线性主成分分析方法(NLPCA),对中国近50 a夏季降水异常分布的非线性特征进行了分析。结果表明,中国夏季降水的异常分布具有一定的非线性特征,当夏季降水距平的一维NLPCA近似在非线性主成分取极端相反位相时,对应的空间分布型表现出明显的不对称性;一维NLPCA对夏季原始降水距平场的近似,比传统一维PCA的近似更为逼真。     

一次新型液态CO2播撒效果的数值模拟

利用三维积层混合云人工增雨数值模式对2002年7月11日的一次天气过程进行了由播撒液态CO2引起的微物理量变化及云动力影响的数值模拟。结果表明:播撒后,云中最大上升气流速度增大,由未播撒时的0.37 m/s增大到播撒后的0.54 m/s,播撒使云中出现最大上升速度W的时间比未播撒提前了4 min,表明播撒液态CO2影响了云的动力过程。同时与未播撒相比:云中雨水含量最大值由1.04 g/kg增加到1.40 g/kg;冰粒子含水量的出现提前了88 min,最大值的出现提前了76min;冰粒子浓度的出现提前了72 min,最大值的出现提前了72 min;雪粒子含水量的出现提前了72 min,最大值的出现提前了128 min;云水含量最大值由1.21 g/kg减小到0.87 g/kg。证明了播撒液态CO2后可影响云的微物理过程,从而导致地面降水的增加。     

Quasi-waveform seismic tomography of crustal structures in the capital circle region of China

Seismic tomography is one of the main tools to explore the interior of the earth.In this study,the quasi-waveform seismic tomographic method is used for the first time to reveal the crustal structures in the capital region of China.3-D highresolution V_P,V_S and the Poisson’s ratio models are generated by inverting 29839 direct P-and 29972 direct S-wave traveltimes selected from 3231 local earthquakes.The results reveal strong crustal heterogeneities.The velocity anomalies at shallow depths are well consistent with surface geologic structures.The relatively low-velocity anomaly layer in the middle crust may be the result of multiple phases of tectonic activity.Earthquakes generally occurred on the boundaries of high-and low-velocity and Poisson’s ratio anomalies.There are obvious low-velocity anomalies below the hypocenters of the Tangshan earthquake and the historical Sanhe-Pinggu earthquake,implying the existence of fluids.The similar velocity structures around the hypocenters of the two earthquakes indicate that the occurrences of the two earthquakes may be related to the same mechanism.The highresolution velocity models provide important observational constraints on the small-scale heterogeneities and dynamic mechanism of the crust in the capital region of China.     

Precipitation‐runoff processes in Shimen hillslope micro‐catchment of Taihang Mountain,north China

Precipitation runoff is a critical hillslope hydrological process for downslope streamflow and piedmont/floodplain recharge. Shimen hillslope micro‐catchment is strategically located in the central foothill region of Taihang Mountains, where runoff is crucial for water availability in the piedmont corridors and floodplains of north China. This study analyzes precipitation‐runoff processes in the Shimen hillslope micro‐catchment for 2006–2008 using locally designed runoff collection systems. The study shows that slope length is a critical factor, next only to precipitation, in terms of runoff yield. Regression analysis also shows that runoff is related positively to precipitation, and negatively to slope length. Soil mantle in the study area is generally thin and is therefore not as critical a runoff factor as slope length. The study shows a significant difference between overland and subsurface runoff. However, that between the 0–10 and 10–20 cm subsurfaces is insignificant. Runoff hardly occurs under light rains (<10 mm), but is clearly noticeable under moderate‐to‐rainstorm events. In the hillslope catchment, vertical infiltration (accounting for 42–84% of the precipitation) dominates runoff processes in subsurface soils and weathered granite gneiss bedrock. A weak lateral flow (at even the soil/bedrock interface) and the generally small runoff suggest strong infiltration loss via deep percolation. This is critical for groundwater recharge in the downslope piedmont corridors and floodplains. This may enhance water availability, ease water shortage, avert further environmental degradation, and reduce the risk of drought/flood in the event of extreme weather conditions in the catchment and the wider north China Plain. Copyright © 2011 John Wiley & Sons, Ltd.     

JCXA——733型电子探针快速半定量分析程序

在近代科学技术发展前缘之一的微束分析中,电子探针X射线显微分析仪是目前相当活跃的微区微量物质成份分析的设备.六十年代初期,电子探针开始被应用于地质领域进行矿物成份分析,至今它已成为矿物岩石学,地球化学、矿床综合评价及综合利用等众多科研课题研究的重要手段.我们使用的JCXA-733型电子探针装配的是美国DEC公司PDF-11型电子计算机,RX02双软盘驱动装置、LA-36型宽行打字机,RT-1l操作系统     

华南铀矿省铀矿构造成矿作用及其时空演化

华南铀矿省内已发现的工业铀矿床类型有花岗岩型、火山岩型、碳硅泥岩型、碳酸盐岩型和砂岩型。在空间上。铀矿床受环形及线性构造控制,并受上地幔构造制约。幔凸、幔凹阳地幔变异带互相交错,造成本区地幔的极不均一性,这是本矿省成矿的深部地质构造背景。通常铀矿床呈面型成环状分布,大型环形构造控制铀矿省,中型和小型环形构造控制铀矿田和矿床的产出。