大比例尺全野外数字化测图

全野外数字化测图的基本思想是将野外采集的各种有关地物和地貌信息转化为数字形式,通过数据接口传输给计算机进行处理,得到内容丰富的电子地图,需要时由电子计算机的图形输出设备(如显示器、绘图仪)绘出地形图或各种专题地图。     

湘鄂赣二叠纪岩相古地理研究

湘鄂赣二叠纪沉积盆地是在华南陆块基础上发育而成,具有扬子克拉通北缘被动大陆边缘盆地、扬子克拉通盆地、湘赣板内拉张盆地和华夏克拉通边缘盆地等四类。根据古暴露等标志,建立了各类盆地的沉积层序,并进行了区域对比。在此基础上,本文着重运用层序地层编图法编制了湘鄂赣二叠纪岩相古地理图,深化了该区岩相古地理研究,详细建立了沉积体系域模式和岩相古地理演化特点和控制因素。     

Groundwater quality and its suitability for drinking and agricultural use in Chithar River Basin, Tamil Nadu, India

Hydrochemistry of groundwater in Chithar Basin, Tamil Nadu, India was used to assess the quality of groundwater for determining its suitability for drinking and agricultural purposes. Physical and chemical parameters of groundwater such as electrical conductivity, pH, total dissolved solids (TDS), Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^–, HCO₃^–, CO₃^2–, SO₄^2–, NO^–₃, F^–, B^– and SiO₂ were determined. Concentrations of the chemical constituents in groundwater vary spatially and temporarily. Interpretation of analytical data shows that mixed Ca–Mg–Cl, Ca–Cl and Na–Cl are the dominant hydrochemical facies in the study area. Alkali earths (Ca²⁺, Mg²⁺) and strong acids (Cl^–, SO₄^2–) are slightly dominating over alkalis (Na⁺, K⁺) and weak acids (HCO₃^–, CO₃^2–). The abundance of the major ions is as follows: Na⁺ Ca²⁺ Mg²⁺ > K⁺ = Cl^– > HCO₃^–> SO₄^2– > NO₃^– > CO₃^2– . Groundwater in the area is generally hard, fresh to brackish, high to very high saline and low alkaline in nature. High total hardness and TDS in a few places identify the unsuitability of groundwater for drinking and irrigation. Such areas require special care to provide adequate drainage and introduce alternative salt tolerance cropping. Fluoride and boron are within the permissible limits for human consumption and crops as per the international standards.     

深港西部通道填海区地下水铜、钒、铊、镉、钨迁移的实验研究

填海工程使滨海地区的地下水物理化学条件改变,导致该区域地下水中重金属浓度升高。本文以深港西部通道填海区为例,采用实验室模拟填海条件的办法,初步探讨了影响填海区地下水重金属迁移的关键因素。模拟实验结果表明,填海区地下水中钨元素含量升高与地下水淡化、淤泥氧化过程以及填料风化有关;铜元素含量升高则与淤泥氧化过程以及填料风化有关;钒元素含量升高与地下水淡化和淤泥氧化过程有关,而其他元素含量升高则主要与填料风化释放有关。     

Geodynamic setting,structure, and composition of continuous trachybasalt-trachyandesite-rhyolite series in the north of Altai-Sayan area: the role of crust-mantle interaction in continental magma formation

The geologic positions and geochemical and isotope parameters of the Ordovician-early Silurian and Early-Middle Devonian continuous volcanic series of the Minusa basin and its mountainous framing are compared. Both series are composed mostly of moderately alkaline rocks with variations in SiO₂ contents from 45 to 77 wt.%. The Ordovician-early Silurian series differs from the Early-Middle Devonian one in lower contents of TiO₂ (< 1.7 wt.%) and Fe₂O_3tot and higher contents of Al₂O₃ in all rock varieties and in the more fractionated REE patterns of trachybasalts. The compositions of both series reflect two simultaneous mechanisms of magma evolution. The main process was fractional crystallization leading to the formation of rocks from trachybasalts to trachyrhyodacites. The accessory mechanism was the contamination of fractionated melts by crustal material, anatectic melting of crust, and mixing of deep-seated magmas with crustal melts. These processes had specifics at each stage and were controlled by the composition of the sources of parental melts. Their geochemical and isotopic parameters (high alkalinity, high contents of lithophile elements, negative anomalies of Nb, Ta, and Ti, and enrichment in radiogenic Sr) point to the interaction of mantle plumes with the lithospheric mantle that was metasomatically transformed during the preceding Vendian-early Cambrian subduction processes.     

气候变暖背景下1961—2010年宁夏旱涝灾害空间分布特征和变化规律

利用宁夏20个气象站1961—2010年实测气象资料,采用线性趋势分析、Mann-Kendall非参数检验、标准化降水指数等数理分析方法,对宁夏近50年旱涝灾害时空变化特征进行分析。结果表明:①1961—2010年宁夏气候暖干化趋势明显,增温速率为0.38 ℃/10a,远高于全国和西北地区;②1961—2010年宁夏降水量波动减少且具有整体性,雨量带明显南移,干旱、半干旱区域逐年扩大。③1961—2010年宁夏旱涝灾害交替发生,干旱化趋势明显。④在旱灾方面,宁夏南部山区旱灾频率相对较低,从南向北旱灾频率逐渐上升。北部灌溉区以轻微干旱为主,严重干旱和极端干旱主要发生在中部干旱区。⑤在涝灾方面,宁夏南部山区涝灾相对较少,依然呈现由南向北涝灾频率逐渐上升的空间格局。中等以上涝灾南部山区相对较多,严重湿润和极端湿润主要发生在北部引黄灌溉区。     

四渡河特大桥GPS控制网的布设及成果分析

介绍四渡河特大桥GPS控制网,采用一种新颖的平差计算方式,解决了与周边控制网的接边精度问题,解决了大山区大高差对GPS施工控制网的精度影响。实际验证了国产单频静态GPS接受机,也能进行高精度的施工控制测量。     

Hydrothermal Mineralization on the Mesoproterozoic Passive Continental Margins of China： A Case Study of the Langshan-Zha＇ertaishan Belt, Inner Mongolia, China

Most ore-forming characteristics of the Langshan-Zha‘ertaishan hydrothermal exhalation belt, which consists of the Dongshengmiao, Huogeqi, Tanyaokou and Jiashengpan large-superlarge Zn-Pb-Cu-Fe sulfide deposits, are most similar to those of Mesoproterozoic SEDEX-type provinces of the world. The characteristics include: (1) All deposits of this type in the belt occur in third-order fault-basins in the Langshan-Zha‘ertaishan aulacogen along the northern margin of the North China Platform; (2) these deposits with all their orebodies hosted in the Mesoproterozoic impure dolomite-marble and carbonaceous phyllite (or schists) have an apparent stratabound nature; ores display laminated and banded structures, showing clear depositional features; (3) there is some evidence of syn-sedimentary faulting, which to a certain extent accounts for the temporal and spatial distribution and the size of the orebodies in all deposits and the formation of intrabed conglomerates and breccias; (4) they show lateral and vertical zonation of sulfides; (5) The Cu/(Pb Zn Cu) ratio of the large and thick Pb Zn Cu orebodies gradually decreases from bottom to top; and (6) barite is interbedded with pyrites and sometimes with sphalerite. However, some characteristics such as the Co/Ni radio of the pyrites, the volcanism, for example, of the Langshan-Zha‘ertalshan metallogenic belt, are different from those of the typical SEDEX deposits of the world. The meta-basic volcanic rock in Huogeqi, the sodic bimodal volcanic rocks in the Dongshengmiao and potassic bimodal-volcanic rocks with blastoporphyfitic and blasto-glomeroporphyritic texture as well as blasto-amygdaloidal structure in the Tanyaokou deposits have been discovered in the only ore-bearing second formation of the Langshan Group in the past 10 years. The metallogeny of some deposits hosted in the Langshan Group is closely related to syn-sedimentary volcanism based on the following facts: most of the lead isotopes in sphalerite, galena, pyrite, pyrrhotite and chalcopyrite plot on both sides of the line for the mantle or between the lines for the mantle and lower crust in the lead isotope composition diagram; cobalt content of some pyrites samples is much higher than the nickel content (Co/Ni= 11.91-12.19). Some volcanic blocks and debris have been picked out from some pyritic and pyrrhotitic ores. All Zn-Pb-Cu-Fe sulfide orebodies in these deposits occur in the strata overlying metamorphic volcanic rocks in the only ore-bearing second formation. In the Jiashengpan deposit that lacks syn-sedimentary volcanic rocks in the host succession only Pb and Zn ores occur without Cu ore, but in the Dongshengmiao, Tanyaokou and Huogeqi deposits with syn-sedimentary volcanic rocks in the host succession Cu ores occur. This indicates a relatively higher ore-forming temperature. The process of synsedimentary volcanic eruption directly supplied some ore-forming elements, and resulted in secular geothermal anomaly favorable for the circulation of a submarine convective hydrothermal system, which accounts for the precipitation of deep mineralizing fluids exhaling into anoxidic basins along the syn-sedimentary fault system in the Langshan-Zha‘ertai rift. The Dongshengmiao, Tanyaokou, and Huogeqi deposits hosted in the Langshan Group appear to be a transitional type of mineral deposit between SEDEX and VMS-types but with a bias towards SEDEX, while the Jiashengpan deposit hosted in the Zha‘ertai Group is of a characteristic SEDEX type. This evidence, together with other new discoveries of Mesoproterozoic volcanic rocks and the features of lithogeny and metallogeny of the Bayun Obo deposit in the neighborhood emphasize the diversity, complexity and uniqueness of the Mesoproterozoic Langshan-Zha‘ertal-Bayun Obo ore belt.