夏季红枫湖地区农田土壤-大气界面汞交换通量的初步研究   总被引：11，自引：2，他引：11  

王少锋  冯新斌  仇广乐  付学吾 《矿物岩石地球化学通报》2004,23(1):19-23

采用动力学通量箱法(Dynamic Flux Chamber)与高时间分辨率大气测汞仪联用技术对贵州红枫湖地区土壤-大气界面间汞交换通量进行了初步研究.结果显示,红枫湖地区土壤-大气界面间汞交换通量变化范围为-8.6 ng～215.3 ng@m-2@h-1,平均27.4士40.1 ng/m2@h(n=255);且土壤与大气界面间的汞交换是双向的既有土壤汞的释放,又有大气汞的沉降,主要以土壤汞的释放为主(n释放=253,n沉降=2n).土壤汞的释放通量与土壤温度、气温、光照强度有强相关关系,相关系数分别为0.80、0.83、0.74.  相似文献   

塔里木盆地西部古岩盐地质地球化学特征与成钾条件分析   总被引：11，自引：1，他引：11  

谭红兵  马海州  马万栋  董亚萍  张西营  许建新 《矿物岩石地球化学通报》2004,23(3):194-199

塔里木盆地是我国重要的成盐盆地,为我国最有远景的找古钾矿地区之一。本文通过多年野外实地调查和大量岩盐样品的化学分析,特别是岩盐中可以指示沉积阶段的Br×103/Cl系数等区域分布特征,联系前人研究资料,分别从构造环境、地层和岩相古地理、地球化学特征等方面进行了成钾条件分析。结果表明,莎车盆地西部喀什坳陷和库车盆地中部拜城坳陷宏观地质特征均有利于钾盐沉积;岩盐地球化学组成相对于正常海相沉积表现出明显的贫Br特征,属海陆交互相或海源陆相沉积。相比之下,莎车盆地的喀什次级坳陷是目前最有前景的找钾远景区。  相似文献   

无机盐超细粉体制备技术的回顾与展望   总被引：3，自引：0，他引：3       下载免费PDF全文

吴健松  李海民 《盐湖研究》2004,12(3):50-54

评述了制备无机盐超细粉体的传统方法以及一些传统方法的改进 ,对当前几种新技术做了介绍与展望  相似文献   

An automated salt‐tracing gauge for flow‐velocity measurement     

Olivier Planchon  Norbert Silvera  Raphael Gimenez  David Favis‐Mortlock  John Wainwright  Yves Le Bissonnais  Gerard Govers 《地球表面变化过程与地形》2005,30(7):833-844

This article introduces the SVG (salt‐velocity gauge), a novel automated technique for measuring flow velocity by means of salt tracing. SVG allows a high measuring rate (up to one every 2 seconds), short control section length (down to 10 cm), high accuracy (+[sol ]?1·5 cm s^?1), and unbiased calculation of the mean velocity in experimental conditions with turbulent, supercritical flow. A few cubic centimetres of saturated salt solution (NaCl) are injected into the flow at regular time intervals using a programmable solenoid valve. The tracer successively passes two conductivity probes placed a short distance downstream. The transformation of the signal between the two probes is modelled as a one‐dimensional diffusion wave equation. Model calibration gives an estimation of the mean velocity and the diffusion for each salt plume. Two implementations of the SVG technique are described. The first was an outdoors simulated rainfall experiment in Senegal (conductivity probes at 40 cm apart, 8 Hz measurement rate, salt injections at 10 second intervals). Mean velocity was estimated to range between 0·1 and 0·3 m s^?1. The second was a laboratory‐based flume experiment (conductivity probes at 10 cm apart, 32 Hz, salt injections at 2 second intervals). Another SVG with probes at 34 cm apart was used for comparison. An acoustic Doppler velocimeter (ADV) was also used to give an independent assessment of velocity. Using the 10 cm salt gauge, estimated mean velocity ranged from 0·6 to 0·9 m s^?1 with a standard deviation of 1·5 cm s^?1. Comparisons between ADV, 10 cm SVG and 34 cm SVG were consistent and demonstrated that the salt‐tracing results were unbiased and independent of distance between probes. Most peaks were modelled with r² > 90 per cent. The SVG technology offers an alternative to the dye‐tracing technique, which has been severely criticized in the literature because of the wide interval of recommended values for the correction factor α to be applied to the timings. This article demonstrates that a fixed value of α is inappropriate, since the correction factor varies with velocity, diffusion and the length of the control section. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

“Evidence for Triassic salt domes in the Tunisian Atlas from gravity and geological data” by C. Jallouli et al., Tectonophysics 396 (2005) 209–225     

Christopher J. Talbot 《Tectonophysics》2005,406(3-4):249-254

  相似文献   

塔里木盆地西部古盐岩同位素地球化学与成钾预测研究   总被引：5，自引：0，他引：5  

谭红兵  马海州  许建新  肖应凯  王建国  李廷伟 《地球学报》2005,26(Z1):174-179

我国钾盐资源紧缺，寻找优质大型钾盐矿床一直是国家资源普查的重要目标这一。塔里木盆地在其地史发展过程中，曾与广海相通，多期海水的侵入和间断，以及适宜的构造、古地里环境具备成钾的基本地质条件，因此一直被列为我国寻找古钾矿的重点地区。为了更准备地判断其成盐的海陆相特征，即成盐物质的主要来源，以及岩盐沉积之前的古卤水蒸发浓缩阶段，预测更有前景的成钾远景区，论文选择了蒸发岩沉积序列中的石膏及石盐矿物，分别分析了其硫同位素及氯同位素分布特征。结果表明，非还原环境下沉积的石膏硫同位素可以准确判断盐岩沉积的海相、陆相和海陆交互沉积特征，氯同位素可以判断岩盐的沉积阶段。应用这两个同位素新指标分析，塔里木盆地西部喀什次级构造凹陷晚白垩世盐岩沉积接近海相沉积类型，而且岩盐沉积阶段较晚，是一最有利成钾远景区。  相似文献   

江苏王港盐沼的现代沉积速率   总被引：35，自引：0，他引：35  

王爱军  高抒  贾建军  潘少明 《地理学报》2005,15(1):61-70

江苏海岸湿地总面积超过5000km^2，但围垦活动的加剧使盐沼湿地面积迅速减少；为了达到海岸防护、保滩促淤的目的，先后引种了大米草和互花米草。通过采集江苏王港潮滩盐沼湿地9处柱状样和挖取探槽剖面，以及对沉积剖面样品进行^210Pb和^137Cs测年分析，探讨了^210Pb的本底及影响^210Pb富集的因素，估算了王港盐沼湿地的现代沉积速率。王港潮滩盐沼沉积物对^210Pb的吸附作用较弱；受风暴潮、生物扰动、物源变化及实验误差等因素的影响，在^210Pbex剖面上出现了数据异常点，将这些数据点剔除后计算得到的沉积速率为33cm yr^-1，^137Cs测年显示，该地区1963年以来的平均沉积速率3．1cm yr^-1，与^210Pb法及前人研究结果相一致。根据一个典型剖面的^137Cs测年数据分析，王港潮滩盐沼的沉积过程根据地貌特征的不同可分3个阶段，大米草覆盖阶段滩面高程迅速增加，互花米草的生长提高了滩面淤积速率。  相似文献   

Variation of stream temperature among mesoscale habitats within stream reaches: southern Appalachians          下载免费PDF全文

S. Lynsey Long  C. Rhett Jackson 《水文研究》2014,28(7):3041-3052

Stream mesoscale habitats have systematic topographic relationships to hyporheic flow patterns, which may create predictable temperature variation between mesoscale habitat types. We investigated whether systematic differences in temperature metrics occurred between mesoscale habitats within reaches of small streams tributary to the upper Little Tennessee River, southern Appalachians. Surface water temperature was recorded over three or four mid‐summer days in four mesoscale habitat types: riffle, main riffle, pool and alcove in 44 stream segments (sites). Temperature metrics were calculated for each mesoscale habitat relative to the mean value of the metric over the stream: Δ maximum temperature, Δ average maximum temperature and Δ maximum daily variation and also for each site: standard deviation of the maximum temperature and average diurnal variation (ADV). Sites were categorized as fully or partially forested. Pool tailouts had statistically significantly lower Δ maximum temperature and Δ average maximum temperature than riffle tailouts in partially forested sites, although differences were small. This was the opposite of what was expected in the presence of hyporheic exchange, indicating hyporheic exchange is not a dominant driver of mesoscale habitat temperatures at these sites. Temperature differences between mesoscale habitat units were small and unlikely to have ecological significance. We also evaluated relationships between stream temperature and riparian condition, watershed % impervious surfaces, watershed % non‐forested and elevation. ADV and standard deviation of the maximum temperature were significantly higher in partially forested sites, indicating that partially forested sites have greater temperature ranges and spatial variation of maximum temperatures. ADV decreased with elevation and increased with % impervious surfaces. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Deducing the spatial variability of exchange within a longitudinal channel water balance          下载免费PDF全文

Noah M. Schmadel  Bethany T. Neilson  Tamao Kasahara 《水文研究》2014,28(7):3088-3103

Developing an appropriate data collection scheme to infer stream–subsurface interactions is not trivial due to the spatial and temporal variability of exchange flowpaths. Within the context of a case study, this paper presents the results from a number of common data collection techniques ranging from point to reach scales used in combination to better understand the spatial complexity of subsurface exchanges, infer the hydrologic conditions where individual influences of hyporheic and groundwater exchange components on stream water can be characterized, and determine where gaps in information arise. We start with a tracer‐based, longitudinal channel water balance to quantify hydrologic gains and losses at a sub‐reach scale nested within two consecutive reaches. Next, we look at groundwater and stream water surface levels, shallow streambed vertical head gradients, streambed and aquifer hydraulic conductivities, water chemistry, and vertical flux rates estimated from streambed temperatures to provide more spatially explicit information. As a result, a clearer spatial understanding of gains and losses was provided, but some limitations in interpreting results were identified even when combining information collected over various scales. Due to spatial variability of exchanges and areas of mixing, each technique frequently captured a combination of groundwater and hyporheic exchange components. Ultimately, this study provides information regarding technique selection, emphasizes that care must be taken when interpreting results, and identifies the need to apply or develop more advanced methods for understanding subsurface exchanges. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

基于分光光度法的多量程海水营养盐原位传感器检测系统设计     

綦声波  任军博  马然  张述伟 《海洋科学》2019,43(11):76-83

针对传统海水营养盐检测方法不能满足海水营养盐长期原位监测需求的问题,研制了一种基于分光光度法的多量程海水营养盐原位传感器检测系统,通过对系统的高度集成及对多量程检测、低功耗技术、漏液保护技术的应用,实现了对海水5项营养盐参数快速、宽范围、高精度的原位测量。经过实验室和青岛中苑码头现场测试,表明本营养盐传感器检测系统具有低功耗、高可靠性能,可满足对5项营养盐参数的快速精确测量要求,实现了对海水营养盐参数的原位监测,为相关部门及时了解海洋生态环境和水体富营养化程度提供了数据支持,具有重大现实意义。  相似文献