Types,geological features and geodynamic significances of gold-copper deposits in the Kanggurtag metallogenic belt,eastern Tianshan,NW China

Occupying the middle of the central Asia Paleozoic accretionary and collisional orogenic belt, the eastern Tianshan area has a great economic potential due to Au-Cu mineralization during syn- and post- orogenic events. In the Kanggurtag Au-Cu metallogenic belt, three major types of gold deposits have been recognized: ductile-shear-zone-hosted gold deposits, magmatic hydrothermal gold deposits, and epithermal gold deposits. Four kinds of copper deposits have also been identified recently: the porphyry-type, the skarn-type, the magmatic type, and volcanic/sedimentary-type. Tectonically, the development of these late Paleozoic gold and copper deposits was closely associated with the subduction and collision of the ancient Tianshan ocean that intervened between the Tarim craton and the Siberian block. In the early to mid-Carboniferous, N-dipping subduction beneath the Dananhu arc generated magmatic intrusions, leading to formation of the porphyry Cu deposits. The magmatic front migrated southward to form the Yamansu arc upon the Kanggurtag accretionary wedge. In the latest Carboniferous to early Permian, during the closure of the ancient Tianshan ocean, large mafic-ultramafic complexes were emplaced, resulting in several magmatic copper-nickel deposits. Gold deposits of the shear-zone-type are controlled by the Kanggurtag ductile shear zone, which is related to collisional orogenesis. The epithermal gold deposits are associated with extensional tectonics and post-tectonic volcanic activity. The tectonic settings, geological features, and temporal and spatial distributions of these different types of gold and copper deposits reflect, to a great extent, the accretionary and collisional tectonics that occurred between the northern margin of the Tarim block and the southern margin of the Siberian block.     

中小城市基础地理信息建设中的问题与建议

空间基础地理信息是城市信息基础设施建设的重要组成部分,中小城市地理信息系统建设的核心是空间基础数据。本文对我国中小城市空间基础地理信息建设现状和存在的问题进行了分析,认为目前中小城市的规划和勘测部门在空间基础地理建设中主要存在数据形式多样、标准不统一和更新不力等问题,对此提出了一些关于数据库建设和数据更新的建议。     

Human-induced change in sedimentary trace metals and phosphorus in Chaohu Lake,China, over the past half-millennium

We present a sedimentary geochemical record of human perturbation in the watershed and related changes in trace metals (Cr, Ni, Zn and Pb), phosphorus and abundant rock-forming elements (Al, Fe, K, Mg, etc.) in Chaohu Lake over the past 500 years, a period spanning historical agricultural expansion and modern economic development. The record exhibited a stable terrestrial detrital input to Chaohu Lake before ca. 1540 AD, a period with less human perturbation of the watershed, which resulted in low and constant values of trace metals and phosphorus (TP) concentrations as well as Al, Fe, K, Mg, fine silt (<16 μm), the chemical index of alteration (CIA) and K/Na ratio. Two periods of successive marked increases in Al, Fe, K, Mg, fine silt, chemical index of alteration (CIA) and K/Na ratio occurred after ca. 1540 AD and 1950 AD. The former period apparently resulted from enhanced well-weathered topsoil erosion in the watershed related to the expansion of arable land, and the latter resulted from further enhancement of human perturbation in the watershed during the modern period. Concentrations of trace metals and TP were positively correlated with that of the rock-forming elements and fine silt. Trace metal pollution was limited during 1540–1950 AD, according to the low enrichment factors (EFs = 0.8–1.1), when an increase in trace metal concentrations was also linked to changes in detrital input. In addition to detrital regulation, pollution also contributed to an increase in TP concentrations (average EF 1.4) during 1540–1950 AD and the average accumulation rate of anthropogenic phosphorus was 87.3 mg m⁻² a⁻¹. Anthropogenic phosphorus increased further and Pb and Zn pollution also occurred after 1950 AD, reaching maximum values after 1980 AD, when the average accumulation rates of anthropogenic Zn, Pb and phosphorus (mainly in the form of NaOH-P) were 242.2, 43.3 and 811.8 mg m⁻² a⁻¹, respectively. The increase in phosphorus pollution in recent decades is probably from the domestic sewage sources of Hefei City and non-point sources related to agricultural utilization of commercial fertilizer, whereas Zn and Pb pollution is probably derived mainly from industrial sources of Hefei City, as deduced from their spatial variations in the sediments of the river mouths.     

基于分区和多元数据的青藏高原温泉区域多年冻土分布研究

以野外勘探、室内理论分析与建模为主要研究方法,以数字高程模型(GDEM)和实测数据为基础进行统计分析,发现坡向对多年冻土分布具有重要影响。针对青藏高原温泉区域地形的复杂性,基于分区的方法将研究区分为平原区和山区两个地形区。对于平原区来说,考虑到苦海湖泊对多年冻土的影响,将苦海滩地单独划出并采用专家知识完成冻土制图,其余平原区采用建立的地温模型进行冻土制图;对于山区来说,通过定量化研究坡向对冻土地温的影响建立了基于坡向调整作用下的地温模型,应用此模型完成了山区的冻土分布图。以地温作为冻土类型划分的依据,分析了研究区域冻土的空间分布与特征,结果表明:多年冻土的分布面积为1 681.4km2,占整个区域的66.7%,其中,过渡型和亚稳定型多年冻土为主要多年冻土类型,两者占整个研究区域的50.8%,其次为不稳定型多年冻土(11.4%),稳定型和极稳定型多年冻土的面积比例相对较小(4.4%和0.2%)。从空间分布格局来看,冻土分布具有明显的垂直分带特征,随着海拔高度的升高,冻土地温逐渐降低,冻土类型依次经历季节冻土-不稳定型多年冻土-过渡型多年冻土-亚稳定型多年冻土-稳定型多年冻土-极稳定型多年冻土的变化。     

基于场理论的甘肃省产业关联度分析

基于物理学中的场理论,以2007年甘肃省投入产出表为主要研究对象建立产业关联梯度场模型,计算甘肃省42个行业的产出梯度、影响力梯度、感应度梯度及其排名,从经济空间梯度的角度对各产业进行剖析,并以产业关联梯度场模型对甘肃省各产业在经济空间中的地位、作用及其动态变化情况进行量化分析,对今后不同产业在产业经济空间中的地位、作用、影响及其变化情况做出预测,并对甘肃省三次产业在经济空间中的结构进行分析,为今后甘肃省产业结构的战略调整提供决策依据。     

Performance of ENSEMBLES regional climate models over Central Europe using various metrics

We show the evaluation of ENSEMBLES regional climate models (RCMs) driven by reanalysis ERA40 over a region centered at the Czech Republic. Attention is paid especially to the model ALADIN-CLIMATE/CZ, being used as the basis of the new climate change scenarios simulation for the Czech Republic. The validation criteria used here are based on monthly or seasonal mean air temperature and precipitation. We concentrate not only on spatiotemporal mean values but also on temporal standard deviation, inter-annual variability, the mean annual cycle, and the skill of the models to represent the observed spatial patterns of these quantities. Model ALADIN-CLIMATE/CZ performs quite well in comparison to the other RCMs; we find its performance satisfactory for further use for impact studies. However, it is also shown that the results of evaluation of the RCMs’ skill in simulating observed climate strongly depend on the criteria incorporated for the evaluation.     

北京市强降雨分区及重现期研究

利用北京观象台1841—2008年年降水量资料及近50年北京市20个气象站和82个雨量站资料分析了北京地区降水量的时间和空间变化规律,对北京地区的降雨进行分区研究,并结合观象台站逐分钟降雨资料应用广义偏态分布（GPD）方法分析了北京地区不同历时降雨量重现期。结果表明：近168年来,北京地区有两个多雨时段和两个少雨时段,目前北京处于20世纪90年代至今的少雨时段内。70至80年代,北京地区强降雨主要为全市区域性降雨,90年代之后北京的短历时强降雨呈现出局地性的特征,降水分布不均,强降水中心大致成东北一西南向带状分布。根据北京市降雨EOF分析,将北京市划分为4个降雨分区,分别是山后区、城市中心区、东北部山区和东南部平原区。其中城区代表站观象台站多个历时不同重现期降雨量分析结果经过与现行排水规范对比表明,重现期模拟结果可靠。     

实时精密单点定位中的数据预处理研究

提出了适用于实时环境的一套数据预处理方案,包括钟跳修复、联合使用Geometry-Free和Melbourne-Wübbena组合进行周跳探测。通过丰富的实验算例,说明了对观测值进行钟跳修复的必要性;证明了联合使用GF与MW组合能够准确有效地探测出实际数据中存在的以及手工模拟加入的周跳。     

DZZ2型自动站监控软件数据故障分析与处理

2010年4月8日16时至9日10时,霍州市气象局自动站出现故障,监控软件无法正常显示各气象要素实时数据,通过认真分析查找原因,逐步排查故障,最终使问题得以圆满解决。本文对该次故障现象与分析处理过程进行了总结。