用于同位素测年的自生伊利石分离纯化流程探索   总被引：8，自引：1，他引：8       下载免费PDF全文

张彦  陈文  杨慧宁 《地球学报》2003,24(6):622-626

沉积岩中自生矿物与碎屑矿物的分离问题是制约沉积岩定年的主要问题之一。本文以浙江和川西地区的粘土矿物为例，介绍了沉积岩中自生伊利石与碎屑矿物的一般分离过程，具体包括悬浮液的制备过程、高速离心机的条件实验和8个样品的分级实验，确定了较佳的分级参数，并对分级后的各级别进行了X-射线衍射(XRD)分析。X-射线衍射结果表明，随着粒度的减小，各种杂质的含量都在逐渐减少，在小于0．2μm的粒级中，已检测不出石英、钾长石、钠长石、方解石、白云石等杂质的存在，其中有3个产品的成岩混层含量达到100％，说明本次实验的分离纯化流程是比较成功的。综合考虑粒度和自生伊利石的纯度，一般情况下，以0．1～0．2μg粒级的产品用于Ar-Ar和K-Ar测年较合适。但在实际进行年龄分析时，一定要先进行XRD和透射电镜分析，只有确定其成岩混层I／S的含量近100％(至少在95％以上)及混层中S的含量小于25％时，才可用于Ar—Ar和K—Ar年龄测定。  相似文献   

吉林省某锑矿分离砷的研究   总被引：1，自引：0，他引：1  

宋发兴  万飞  赵向前  刘晓菊 《吉林地质》2007,26(3):78-83

采用以水玻璃、硫酸为主的组合抑制剂,浮砷抑锑。较好地解决了砷锑分离的难题,使锑的精矿含砷降到符合国家质量标准。  相似文献   

氯化钡法在盐湖高锂卤水中高效分离硫酸根的研究          下载免费PDF全文

马丽  孟永涛  毕秋艳  房晓宇  关云山 《盐湖研究》2021,29(3):68-75

在生产碳酸锂的工艺中,尤其除硫过程中,锂会伴随其它盐类析出,造成锂的大量夹带损失.因此盐湖高锂卤水中硫酸根的脱除对锂的高效富集,提高锂的收率有重大意义.研究以盐湖高锂卤水为原料,通过加入氯化钡,采用化学沉淀法除去卤水中的SO2-4.详细考察了原料配比(SO2-4与Ba2+的摩尔比)、加料方式、加料时间、反应时间、搅拌速...  相似文献   

Impact of precipitation characteristics on soil hydrology in tile‐drained landscapes     

P. Vidon  P. E. Cuadra 《水文研究》2010,24(13):1821-1833

Understanding the variables regulating tile‐flow response to precipitation in the US Midwest is critical for water quality management. This study (1) investigates the relationship between precipitation characteristics, antecedent water table depth and tile‐flow response at a high temporal resolution during storms; and (2) determines the relative importance of macropore flow versus matrix flow in tile flow in a tile‐drained soya bean field in Indiana. In spring, although variations in antecedent water table depth imparted some variation in tile‐flow response to precipitation, bulk precipitation was the best predictor of mean tile flow, maximum tile flow, time to peak, and run‐off ratio. The contribution of macropore flow to total flow significantly increased with precipitation amount, and macropore flow represented between 11 and 50% of total drain flow, with peak contributions between 15 and 74% of flow. For large storms (>6 cm bulk precipitation), cations data indicated a dilution of groundwater with new water as discharge peaked. Although no clear dilution or concentration patterns for Mg²⁺ or K⁺ were observed for smaller tile flow generating events (<3 cm bulk precipitation), macropore flow still contributed between 11 and 17% of the total flow for these moderate size storms. Inter‐drain comparison stressed the need to use triplicate or duplicate tile drain experiments when investigating tile drainage impact on water and N losses at the plot scale. These results significantly increase our understanding of the hydrological functioning of tile‐drained fields in spring, when most N losses to streams occur in the US Midwest. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Reservoir rainfall‐runoff geomorphological model. II: analysis,calibration and validation     

M. Goñi  J. J. López  F. N. Gimena 《水文研究》2013,27(4):489-504

The model presented in the complementary document entitled, Reservoir rainfall‐runoff geomorphological model I: parameter application and analysis is analysed, calibrated and validated in this paper. The accuracy of simulated hydrographs is analysed by means of the efficiency defined by Nash and Sutcliffe. The sensitivity of the influence of five parameters on the behaviour of the model developed is analysed. Two different calibration and validation processes of Reservoir rainfall‐runoff geomorphological model are performed in Aixola watershed. Twelve events have been selected for calibrations and 25 for validations. With the first calibration and validation process, the model parameters are set by assigning the medians' values of the distributions obtained by means of the optimum results. The second process is performed by calibrating the most determinant parameter in the adjustment, which is the one that indicates the proportion of infiltrated water that is retained and does not flow; this is done with an empirical formulation depending on the event characteristics. Subsequently, the obtained results are validated. This last process has achieved very good adjustments in both calibrated and validated events. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Accounting for sparsely observed rainfall space—time variability in a rainfall—runoff model of a semiarid Tunisian basin/Prise en compte d'observations peu denses de la variabilité spatiotemporelle de la pluie dans une modélisation pluie—débit d'un bassin semi-aride Tunisien     

《水文科学杂志》2013,58(4)

Abstract

The management of water excesses and deficits is a major task in semiarid Mediterranean regions, where the variability of rainfall inputs is high at different time and space scales. Thus intense hydrometeorological events, which generate both potential resource and hazards, are of major interest. A simple method is proposed, with the example of the Skhira basin (192 km²) in central Tunisia, to account for the event space–time variability of rainfall in a rainfall–runoff model, in order to check its influence on the shape, magnitude and timing of resulting hydrographs. The transfer function used is a geomorphology-based unit hydrograph with an explicit territorial significance. Simulations made for highly variable events show the relevance of this method, seen as the first step of a downward approach, and its robustness with respect to the quality and the density of rainfall data.  相似文献   

Groundwater–surface water interactions in a lowland watershed: source contribution to stream flow     

Vijay M. Vulava  Timothy J. Callahan  Martin L. Jones 《水文研究》2012,26(21):3195-3206

The lower coastal plain of the Southeast USA is undergoing rapid urbanisation as a result of population growth. Land use change has been shown to affect watershed hydrology by altering stream flow and, ultimately, impairing water quality and ecologic health. However, because few long‐term studies have focused on groundwater–surface water interactions in lowland watersheds, it is difficult to establish what the effect of development might be in the coastal plain region. The objective of this study was to use an innovative improvement to end‐member mixing analysis (EMMA) to identify time sequences of hydrologic processes affecting storm flow. Hydrologic and major ion chemical data from groundwater, soil water, precipitation and stream sites were collected over a 2‐year period at a watershed located in USDA Forest Service's Santee Experimental Forest near Charleston, South Carolina, USA. Stream flow was ephemeral and highly dependent on evapotranspiration rates and rainfall amount and intensity. Hydrograph separation for a series of storm events using EMMA allowed us to identify precipitation, riparian groundwater and streambed groundwater as main sources to stream flow, although source contribution varied as a function of antecedent soil moisture condition. Precipitation, as runoff, dominated stream flow during all storm events while riparian and streambed groundwater contributions varied and were mainly dependent on antecedent soil moisture condition. Sensitivity analyses examined the influence of 10% and 50% increases in analyte concentration on EMMA calculations and found that contribution estimates were very sensitive to changes in chemistry. This study has implications on the type of methodology used in traditional forms of EMMA research, particularly in the recognition and use of median end‐member water chemistry in hydrograph separation techniques. Potential effects of urban development on important hydrologic processes (groundwater recharge, interflow, runoff, etc.) that influence stream flow in these lowland watersheds were qualitatively examined. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Versuch der Geschlechtsbestimmung beim Wels,Silurus glanis L., mit Hilfe der Diskriminanzanalyse von Brustflossendaten     

Wiesław Wiśniewolski  Janusz Górczyński  Wiesław Madry 《Aquatic Sciences - Research Across Boundaries》1989,51(3):249-259

Width of the first ray of the pectoral fin has been measured in two places for 154 young and 89 adult wels. Statistical relationships between the above characters and fish length as well as its maturity and sex have been proved. Three models of discriminant function for identification of adult fish sex have been derived and verified. The accuracy of sex separation has been 89,5% in a standard sample of wels, and 90,6% in a routine sample, after an adjustment in the procedure.  相似文献   

自然金的化学分离方法     

蔡长金  宋湘荣 《铀矿地质》1989,5(1):45-50

作者用物理方法和化学方法相结合分离了九个矿区的自然金,效果良好,其纯度一般达99％以上。X光、化学分析和物性测试表明,化学处理对自然金的物性、化学成分和结构无明显影响。文中分别对几种矿物组合的化学分离方法作了具体介绍。  相似文献   

Asymptotic Rayleigh instantaneous unit hydrograph     

B. M. Troutman  M. R. Karlinger 《Stochastic Environmental Research and Risk Assessment (SERRA)》1988,2(1):73-78

The instantaneous unit hydrograph for a channel network under general linear routing and conditioned on the network magnitude,N, tends asymptotically, asN grows large, to a Rayleigh probability density function. This behavior is identical to that of the width function of the network, and is proven under the assumption that the network link configuration is topologically random and the link hydraulic and geometric properties are independent and identically distributed random variables. The asymptotic distribution depends only on a scale factor, , where is a mean link wave travel time.  相似文献