锡铁山喷流沉积矿床卤水与海水的相互作用

锡铁山大型铅锌矿床发育有完好的喷流沉积系统,赋矿地层产状倒转。与成矿关系密切的大理岩延长约2km,延深约1km,往深部厚度增大,至代表管道相的网脉状蚀变岩,厚度迅速减薄、尖灭。角砾状非层状铅锌矿体赋存于紧邻网脉状蚀变岩的厚层状大理岩中,条带状层状矿体赋存于外侧条带状大理岩的下盘。对锡铁山矿床两条典型剖面系统的地质地球化学研究表明,近喷口相大理岩与远离喷口相大理岩相比,具有相似的变化规律。以反映远端沉积的剖面为例,自下往上,条带状矿体条带状大理岩块状大理岩,Al2O3、Fe2O3、Sr、B、Tl以及MgO/(CaO MgO)、Na2O/(Na2O K2O)比值等逐渐降低,Sr/Rb、Sr/Ba比值等迅速降低,REE总量降低,分异增强,Eu异常减弱,Ce负异常更加明显;δ18OSMOW=10.1‰～12.5‰,向上增高,δ13CV-PDB=-0.9‰～0.2‰;大理岩87Sr/86Sr=0.7113～0.7148,低于矿石方解石的0.7146～0.7147,高于同时期的正常海相灰岩。综合这些地质地球化学特征,锡铁山矿床的容矿大理岩明显不同于正常海相沉积碳酸盐岩,而是介于喷流卤水与海水特征之间,上部的大理岩中有更多的海水参与。以Sr同位素数据计算出本区大理岩来自海水的组分约占1/3,来自卤水的组分约占2/3,大理岩总体上仍主要分布于喷口附近,更多地受到卤水的影响。通过大理岩的地质地球化学研究揭示出,矿床中发育有两条同生断层,一条沿以网脉状蚀变带代表的管道相分布,另一条分布于25线附近,共同制约着大理岩与成矿物质的堆积。锡铁山矿床可能存在着规模巨大的层状矿体,其分布范围可能超越一直作为重要找矿评价标志的大理岩。     

Combination Features, Paleobiogeographic Affinity and Mass Extinction of the Latest Ordovician （Hirnantian） Rugosan Fauna from Northern Guizhou, China

The rugosan fauna from the Guanyinqiao Bed （latest Ordovician, Hirnantian） of northern Guizhou, China is known to belong to the cold or cool-water type corals. The components of the fauna are solitary corals only, and corallite septa are generally strongly dilated, especially the streptelasmatid corals are dominant comprising 98% of the whole fauna. The Guanyinqiao Bed is rich in rugosans of 18 genera, which are streptelasnmtid Streptelasma （=Helicelasma）, Brachyelasma, Amplexobrachyelasma, Salvadorea, Grewingkia, Borelasma, CrassUasma, Leolasma, KenophyUum, UUernelasma, Paramplexoides, Siphonolasma, Pycnactoides, Dalmanophyllum, Bodophyllum, Axiphoria, Lambeophyllum and cystiphyllid Sinkiangolasma. Although this fauna was fairly abundant in a confined area （northern-northeastern Guizhou, southern Sichuan） during the Hirnantian age, the rugosan mass extinction （generic extinction rate 81%） happened at the end of the Hirnantian Stage. It is conduded that the mass extinction is related to the ending of maximum glaciation and ice cap melting in Gondwana in the southern hemisphere in the latest Hirnantian, resulting in rapid global sea-level rise in the earliest Silurian. In the Upper Yangtze Basin, the sea bottom environments were replaced by anoxic and warmer water during that time, so that the cool-water type rugosan became extinct. The present paper attempts to revise some already described rugose coral genera and species （He, 1978, 1985） and to supplement a few new forms from the Guanyinqiao Bed. Fourteen species of 12 genera are re-described and illustrated, of which one species- Grewingkia latifossulata is new. As a whole, the rugosan fauna of the Guanyinqiao Bed may be correlated with those contemporaneous of North Europe, Estonia and North America, indicating a dose biogeographic affinity to North Europe.     

月亮和太阳的潮汐位产生的地球形变位

采用径向成层的地球模型计算由月亮和太阳的潮汐位所产生的地球形变位。分析的基本出发点是牛顿万有引力位是由随时间变化的质量密度增量产生的;由质量守恒定律,质量密度增量来自未挠动的质量密度的散度和位移矢量场。对质量密度的径向成层模型,采用Dziewonski和Anderson的PREN地球模型(1981);对勒夫(Love)和志田(Shida)数,采用Varga和Denis的模型(1988);对月亮和太阳的潮汐位分别取至3和2阶。计算了地球的形变位。所得结果比用勒夫假定(即δW=K_L(γ)V_(?))计算的结果,相差20％。本文给出了详细的数字结果和讨论。     

试论西宁地区湿陷性黄土的天然孔隙比及含水量对湿陷性的影响

本文依据西宁地区黄土的大量实际资料,对影响黄土湿陷性的两个主要因素(黄土的天然孔隙比、含水量)与黄土湿陷系数的关系进行了综合分析与归纳,论述了这两个因素对湿陷性的影响;并在数理统计基础上,提出了黄土湿陷性的判别式。对西宁黄土区的工程地质评价,具有参考与实用价值。     

高相干点地基InSAR的大气延迟纠正

针对目前地基合成孔径雷达干涉测量技术中大气影响造成的相位延迟校正方法存在的校正精度低、方法复杂、技术要求高等不足,提出了一种基于高相干点的地基InSAR大气延迟相位函数模型校正方案。该方案不需多幅SAR影像,不需人工布点,节省了大量人力物力。以高相干点的相干值作为权阵参与计算,该方法可得到更精确的校正结果。运用该方法将地基雷达对山西省吕梁市林家坪工程滑坡获取的数据进行大气延迟改正的实验。结果表明:所提方案不仅处理方法简单,改正效果明显,而且能满足绝大多数类似工程的精度要求,更为经济实用。     

现代信息技术环境下中学地理在线教学设计探究

无论是出于应对疫情期间“停课不停学、学习不延期”的在线教学急迫需求,还是适应时代发展的教育信息化的变革大趋势,加快中学地理网络在线教学设计研究变得尤为重要和迫切。本文探究了现代信息技术环境下中学地理在线教学设计理论基础与实施的必要性,在此基础上对中学地理在线教学设计基本思路与要点进行了系统分析与研究,以期为中学地理在线教学提供参考与借鉴。     

Spatiotemporal analysis of climate variability (1971–2010) in spring and summer on the Loess Plateau,China

By using the Variable Infiltration Capacity model with Palmer Drought Severity Index (VIC‐PDSI) model and Standardized Precipitation Index (SPI), spatiotemporal trends of climate variation during the main growing seasons for plants of Loess Plateau between 1971 and 2010 were detected and characterized. The VIC‐PDSI model is established by combining the VIC model with PDSI. The simulation results and the grids system of VIC were applied to substitute for the two‐layer bucket‐type model to do the hydrological accounting, which could improve the physical mechanism of PDSI and expand its application range. Our results suggest that the climate of the study area has experienced a drying and warming trend during the past four decades. Apart from some individual years and regions, there was a perpetuation of water deficit over the Plateau both in spring and summer. The drought frequency increased from southeast to northwest in spring, while the drought frequency decreased from southeast to northwest in summer. The climate in the southern part of the Loess Plateau, accounting for 23.3% of the study region, showed a significant drying and warming trend in spring over the past four decades. The climate variability detected by VIC‐PDSI model shows good agreement with that monitored by SPI. Since a large part of the study region frequently suffered from water shortage during the main growing seasons for plants, people living in such drought‐prone areas should take measures to prevent the negative effects on agricultural production, reforestation, and regional food security caused by drought. Copyright © 2013 John Wiley & Sons, Ltd.     

基于指数滤波法估算沟道根区土壤水分

为更加有效获取黄土高原沟道地形根区土壤水分信息,基于表层（0~20cm）土壤水分观测值,采用指数滤波法在样带和沟道尺度对根区（20~80cm）土壤水分进行估算。结果表明,指数滤波法能够较准确估算沟道根区土壤水分,但随着土层深度增加估算误差逐渐增大。当有根区土壤水分初始值时,估算精度明显提高,但主要集中在时间序列前期。指数滤波法关键参数特征时长T的最优值（T_opt）随土层深度增加而增大,呈现每增加20cm,T_opt值较20~40cm增加1倍的变化规律。对于根区某一土层,不同空间位置（样带）和尺度T_opt交换使用没有明显降低土壤水分估算精度,表明指数滤波法对T_opt的空间敏感性较弱。需注意黄土高原区域尺度土壤性质具有极强空间异质性,指数滤波法在更大尺度上对T_opt的敏感性需进一步深入研究。     

Statistical analyses and controls of root-zone soil moisture in a large gully of the Loess Plateau

Soil moisture variability and controls are little known in large gullies of the Loess Plateau which represent complex topography with steep slopes. This study analyzed spatial–temporal variability of soil moisture at the 0–20, 20–40, 40–60, and 60–80 cm depths in a large gully of the Loess Plateau based on root-zone soil moisture measurements for 3 years (2009–2011). The result showed that mean soil moisture, standard deviation (SD), and coefficient of variation, were highly dependent on depth; the highest mean value was observed at the 20–40 cm depth, while the lowest one was at the 0–20 cm depth. The SD increased with mean soil moisture for various depths as soil moisture was relatively wet; however, a transition that SD decreased with mean soil moisture occurred when soil moisture was relatively dry. Positive correlations exist between moisture contents over different depths, and that the relationships of the neighboring layers are relatively high with R ² from 0.70 to 0.76. Correlation analysis, principle component analysis, and stepwise multiple regression analysis showed that soil particle size distribution and topography (slope and elevation) were the main environmental factors controlling soil moisture variability in the large gully.