Insights into groundwater salinization from hydrogeochemical and isotopic evidence in an arid inland basin

In the Manas River basin (MRB), groundwater salinization has become a major concern, impeding groundwater use considerably. Isotopic and hydrogeochemical characteristics of 73 groundwater and 11 surface water samples from the basin were analysed to determine the salinization process and potential sources of salinity. Groundwater salinity ranged from 0.2 to 11.91 g/L, and high salinities were generally located in the discharge area, arable land irrigated by groundwater, and depression cone area. The quantitative contributions of the evaporation effect were calculated, and the various groundwater contributions of transpiration, mineral dissolution, and agricultural irrigation were identified using hydrogeochemical diagrams and δD and δ¹⁸O compositions of the groundwater and surface water samples. The average evaporation contribution ratios to salinity were 5.87% and 32.7% in groundwater and surface water, respectively. From the piedmont plain to the desert plain, the average groundwater loss by evaporation increased from 7% to 29%. However, the increases in salinity by evaporation were small according to the deuterium excess signals. Mineral dissolution, transpiration, and agricultural irrigation activities were the major causes of groundwater salinization. Isotopic information revealed that river leakage quickly infiltrated into aquifers in the piedmont area with weak evaporation effects. The recharge water interacted with the sediments and dissolved minerals and subsequently increased the salinity along the flow path. In the irrigation land, shallow groundwater salinity and Cl^? concentrations increased but not δ¹⁸O, suggesting that both the leaching of soil salts due to irrigation and transpiration effect dominated in controlling the hydrogeochemistry. Depleted δ¹⁸O and high Cl^? concentrations in the middle and deep groundwater revealed the combined effects of mixing with paleo‐water and mineral dissolution with a long residence time. These results could contribute to the management of groundwater sources and future utilization programs in the MRB and similar areas.     

Characteristics of metals in the aerosols of Zhongshan Station, Antarctica

Instrumental neutron activation analysis (INAA) was applied to analyze the bulk, high-volume aerosol samples, collected at Zhongshan Station in the Eastern Antarctica, during 1998-2001, to study the chemical species. .A graphical technique was applied to the INAA data. Results showed that Na, Cl, Mg, Ca, Sr, Br, I, Sr and Rb were marine elements while Al, Sc, Fe and Mn were crustal elements. Compared to marine and crustal elements, five elements (Se、Co、Sb、Zn、Cr) were highly abundant in the aerosols collected at Zhongshan station, which indicated that they might come from the petroleum burning, heating and equipment operation. The presence of pollutant elements suggested that human activities have affected the local environments in Antarctica.     

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都江堰-汶川公路汶川地震次生地质灾害主要特征和形成机理

汶川特大地震发生后, 都江堰至汶川公路两旁次生地质灾害尤为严重, 先后多次完全中断震中交通生命线, 严重地影响了公路的安全运行和灾后重建。通过对汶川地震前后都江堰-汶川公路边坡现场调查资料对比分析, 研究了该地段边坡的主要次生地质灾害类型及其破坏模式、形成机制和时空分布特点。破坏类型主要为碎屑流式、碎裂滑移式崩塌和碎裂-俯冲式、振荡-高速滑移式泥石流等, 造成沿线边坡发生大面积浅表生改造破坏。此类灾害具有丛集性、相关性、分段性的明显特点。成因复杂的高陡岩土体是次生地质灾害的主要物质基础;强烈的场地地震效应和内外动力耦合作用是该地区地质灾害成生的主要因素。      

江苏省区域经济差异的多尺度研究

运用多阶段The il系数嵌套分解法,从空间尺度研究江苏省区域经济差异问题。基本结论是:从市级行政区域单元来看,北部市级之间差异的变化趋势和全省的变化趋势基本是一致的,中部和南部市级之间的差异一直相对较小,而且变化趋势较为缓慢,但是三大地带之间差异一直在增大。从县级行政区域单元来看,市内差异是全省整体差异的重要构成部分,市内差异对于全省整体差异的贡献比三大地带之间差异和市际差异的贡献显著得多。     

孔间电磁波CT法在左江电站火成岩坝基风化结构评价中的应用

孔间电磁波CT法不仅在岩溶探测以及岩浆岩地层岩石风化界面的探测,有广阔的应用前景。针对左江电站坝基岩浆岩地层的霏细岩,岩石中含石英、长石、蒙脱石等矿物,加上应力作用易隐存风化界面及软弱夹层,直接影响坝基安全。提出运用不断改进的孔间电磁波法及CT处理软件,对所获数据进行反演成像,结果显示,实际观测的吸收系数值与岩样测试结果基本吻合。在所探查的3对钻孔剖面,数字图像清晰给出了岩石结构和风化层界面深度,结果已得到钻探验证,为左江电站坝基帷幕灌浆深度提供了可靠依据。     

广州市乡村旅游供给空间结构特征研究

中国乡村旅游主要在大城市周边地区。广州市周边具有丰富的乡村旅游资源,在对广州市乡村旅游的供给主体（已开发的118个乡村旅游设施点）的资料统计前提下,以广州市地理空间信息系统为基础,运用回转半径、旅游地平均城市中心距离、旅游地空间离散指数等定量分析方法,研究得出广州市乡村旅游供给的空间分布总体上存在着乡村旅游地呈现中心递减趋势、沿交通干线集聚寄生的状态、平均城市中心距离各异但差别不显著、空间离散程度呈现产品指向性等多方面特征。     

灰色拓扑方法在广元稻瘟病预测中的应用

病虫害预测预报是粮食安全风险管理的重要内容之一,灰色理论用于病虫害预测是一项有益的探索。以水稻稻瘟病预报为例,本文详细阐述灰色系统理论的建模方法,利用广元市近20年水稻稻瘟病发生面积资料,建立了1个GM (1,1)拓扑预测模型,用于稻瘟病趋势预测,并取得了较为满意的结果。