广西茶山锑矿区萤石成因的稀土元素地球化学研究

对茶山锑矿区大量出现的萤石进行稀土元素地球化学研究,萤石稀土元素具有略向左倾的平坦型和Ce强烈富集,Sm、Eu相对亏损型两种分布形式,萤石是整个热液作用过程的产物。     

国际金价走势及对策

在世界金矿资源勘查、黄金生产、黄金储备和黄金消费资料分析的基础上,作者就金价下跌、我国金价与国际全面接轨对我国特别是对地勘行业的黄金勘查和生产状况的影响进行了分析。作者认为,世界巨量黄金储备是制约目前国际黄金价格的主要因素。但在黄金价格已接近或低于生产成本线的情况下,金价的下跌幅度有限,亦不会长久。我国的黄金企业只有采取规模经营和苦练内功等,方能降低生产成本,提高经营效益,才有资格参与国际竞争。     

冲淤河道水位预报模型及其应用

根据河流动力学基本方程,采用水文学与水-沙关系相结合的方法,建立了适用于不受回水顶托影响,以悬移质为主且水-沙关系良好的冲淤河道的水位预报模型,应用于渭河咸阳-华县河段,精度提高。     

堵江滑坡作坝的主要工程地质问题及利用情况分析

国内外大量的文献资料和作者野外现场调查表明:滑坡堵江成坝形成堰塞湖在山区一带广泛发育,研究发现堵江滑坡作坝存在的工程地质问题主要包括渗透变形、稳定性、沉降及不均匀沉降和砂土液化问题。文中对上述工程地质问题进行了探讨,并对滑坡坝的利用情况进行了实例分析,为开发堵江滑坡坝、堰塞湖蕴含的丰富水利水电资源起指导性作用。     

四川宝兴县大板桥滑坡坝的基本特征及成因机制分析

在野外现场调查的基础上,对四川省宝兴县硗碛水电站下游５００ｍ处的大板桥滑坡坝的基本特征及成因机制进行了分析。     

利用测震台网记录获得加速度波形的方法研究

研究了从测震台网速度记录获得高质量加速度波形的方法，并以天津蓟县台安装的CTSI-EDAS24速度型甚宽带地震仪和EST-Q4128型强。震仪对同一地震记录的处理分析为例，对计算步骤和处理方法进行了详细论述。处理结果的对比分析表明，该方法简单有效，拓宽了数字测震台网波形记录的服务应用范围。     

Statistical analysis of background noise in seismic prospecting

From a conventional viewpoint, seismic‐prospecting background noise is usually regarded as the product of a stationary and Gaussian stochastic process. In this paper, we use statistical methods to investigate the properties of the land‐seismic‐prospecting background noise on stationarity, Gaussianity, power spectral density, and spatial correlation. We use and analyse the passive noise records collected by receiver arrays at different typical geological environments (desert, steppe, and mountainous regions). Differences exist in the statistical properties of the background noise from different geological environments, but we still find some common characteristics. It is shown that the background noise is not strictly stationary and has different stationary properties over different timescales. Most of the noise records appear to be a Gaussian process when examined over a period of about 20 s but are found to be non‐Gaussian when examined over shorter periods of about 1 s. The background noise is a kind of colored noise, and its energy mainly concentrates in the low‐frequency bands. We also find that the spatial correlation of the background noise is weak. The results of this paper provide a scientific understanding about the properties of seismic‐prospecting background noise.     

Climate effects of the GlobeLand30 land cover dataset on the Beijing Climate Center climate model simulations

Land cover is one of the most basic input elements of land surface and climate models. Currently, the direct and indirect effects of land cover data on climate and climate change are receiving increasing attentions. In this study, a high resolution (30 m) global land cover dataset (GlobeLand30) produced by Chinese scientists was, for the first time, used in the Beijing Climate Center Climate System Model (BCC_CSM) to assess the influences of land cover dataset on land surface and climate simulations. A two-step strategy was designed to use the GlobeLand30 data in the model. First, the GlobeLand30 data were merged with other satellite remote sensing and climate datasets to regenerate plant functional type (PFT) data fitted for the BCC_CSM. Second, the up-scaling based on an area-weighted approach was used to aggregate the fine-resolution GlobeLand30 land cover type and area percentage with the coarser model grid resolutions globally. The GlobeLand30-based and the BCC_CSM-based land cover data had generally consistent spatial distribution features, but there were some differences between them. The simulation results of the different land cover type dataset change experiments showed that effects of the new PFT data were larger than those of the new glaciers and water bodies (lakes and wetlands). The maximum value was attained when dataset of all land cover types were changed. The positive bias of precipitation in the mid-high latitude of the northern hemisphere and the negative bias in the Amazon, as well as the negative bias of air temperature in part of the southern hemisphere, were reduced when the GlobeLand30-based data were used in the BCC_CSM atmosphere model. The results suggest that the GlobeLand30 data are suitable for use in the BCC_CSM component models and can improve the performance of the land and atmosphere simulations.     

河南鲁山寒武系第二统辛集组风暴沉积及其相关的遗迹化石*

河南鲁山寒武系第二统辛集组为一套风暴作用影响下的含磷和海绿石的碎屑岩沉积,主要由中厚层石英砂岩及极薄层泥岩与砂岩互层组成。遗迹化石发育在交错层理砂岩以及极薄层泥岩与薄层砂岩互层的层面上。Skolithos sp. 属于风暴衰减期的Skolithos遗迹相机会种(r-选择)遗迹化石,它们以短小的垂直居住潜穴及低遗迹分异度和丰度为特征。Palaeophycus tubularis,P. striatus,Taenidum sp.,Gordia marina,Planolites montanus,P. beverleyensis等属于风暴间歇期的Cruziana遗迹相均衡种(K-选择)遗迹化石,以水平进食、觅食潜穴为主,遗迹分异度和丰度中等。早寒武世风暴衰减期,频繁的风暴事件不利于研究区机会种遗迹化石的保存,同时风暴间歇期持续时间短、风暴停息期不发育,造成均衡类生物殖居窗口期短暂,亦不利于对沉积底质的连续殖居。这种特殊的风暴沉积以及早寒武世造迹生物较差的掘穴能力,导致研究区遗迹化石种类及数量远不及寒武纪以后的风暴沉积。     

High slope stability of diversion power system intake of Jinchuan hydropower station

The excavated height of the left bank slope of the diversion power system intake in Jinchuan hydropower station is about 16o m. The stability and safety of the slope during construction and its operation/utilization become one of the most important geological engineering problems. At the same time, it is also crucial to select a safe and economic excavation gradient for the construction. We studied the problem of how to select a safe and economic slope ratio by analyzing the geological condition of the high slope, including the lithology, slope structure, structural surface and their combinations, rock weathering and unloading, hydrology, and the natural gradient. The study results showed that the use of an excavation gradient larger than the gradient observed during site investigation and the gradient recommended in standards and field practice manuals is feasible. Then, we used the finite element method and rigid limit equilibrium method to evaluate the stability of the excavation slope under natural, rainstorm and earthquake conditions. The calculated results showed that the excavated slope only has limited failure, but its stability is greatly satisfactory. The research findings can be useful in excavation and slope stabilization projects.