新疆第四纪盐类矿产的形成和控制因素——兼论“高山深盆”成盐模式   总被引：1，自引：0，他引：1  

王得林 《新疆地质》1993,(1)

根据袁见齐教授“高山深盆”成盐模式,探讨新疆天山对第四纪盐类矿床的形成和控制作用,阐述了天山地貌、气候、水文特征与盐类矿产的分布规律和特征。认为“高山深盆”并非一定是四周环山的深盆,可以是某一高山与其间深盆或两侧盆地的有机组合。高山的屏障作用造成了垂直的气候分带,在潮湿多雨的山区利于成盐组份的析出并迁移到干旱少雨的闭流深盆中,形成盐类矿床。  相似文献   

Fluctuation in the zooplankton community in two solar salt ponds,Aveiro, Portugal     

N. Vieira  F. Amat 《International Journal of Salt Lake Research》1995,4(4):327-333

The zooplankton of two salt ponds at Aveiro was studied to evaluate its density and diversity. Samples were collected biweekly from the salt ponds Esmolas and Tanoeiras. Samples were first separated into Holoplankton (Copepoda, nauplii,Acartia, Ostracoda and Anostraca) and Meroplankton (Mollusca, Insecta, annelidan larvae and Ichthyoplankton). The Holoplankton was mainly composed of:Acartia tonsa, Acartia sp.,Eurytemora velox, Artemia sp., and harpacticoids and calanoids. In both salt ponds, species diversity was identical, but total zooplankton density was higher in the Tanoeiras salt pond, probably because its physical and chemical characteristics allowed the development of stable communities.  相似文献   

Variability of sulfur along the coastal salt marshes, Quanzhou Bay, China     

《中国地球化学学报》2006,25(B08):11-11

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Nature minéralogique et rôle nutritionnel des argiles de sols céréaliers en région subhumide à semi-aride (Tunisie)     

Habib Ben Hassine 《Comptes Rendus Geoscience》2006,338(5):329-340

The cereal soils of the Northwest of Tunisia derive most of the time, from alluvial deposits or altered remains of carbonated and clayey rocks. Extraction of the clayey fraction permitted to reveal the presence of the following clayey minerals: kaolinite, illite, smectite, chlorite, as well as an illite–smectite interstratified layer, which is present in the deep horizons of the vertisol and in the isohumic soil. The presence of such types of clays shows that the evolution mechanism of soils is weathering of primary minerals inherited from the sedimentary rocks of the Northwest of Tunisia. These clays ensure to soils most of their cationic exchange capacity. Thanks to these clays, which have Ca⁺⁺, Mg⁺⁺ and K⁺ as exchangeable cations, the chemical fertility of these soils is ensured. It may be improved by increasing contents of organic matter, which is naturally few abundant in these soils. To cite this article: H. Ben Hassine, C. R. Geoscience 338 (2006).  相似文献   

Experimental and numerical studies of rock salt strain hardening     

M. Hamami 《Geotechnical and Geological Engineering》2006,24(5):1271-1292

The work presented in this paper comes as part of a research program dealing with the thermomechanical behaviour of rock salt. It aims to study laboratory and in-situ long-term behaviour by means of creep tests with deviator and temperature changes. The laboratory results, using a triaxial multi-stages creep tests, highlighted the strain hardening character of rock salt. Furthermore, the in-situ results, using a borehole dilatometer multi-step creep test, have shown that the drilling is carried out in a weakly stressed pillar. The interpretation of the laboratory results, using the J.LEMAITRE law, did not indicate full agreement with all the test results. As a result a ‘double’ J.LEMAITRE model, which takes into account a double strain hardening variable, has been put forward. The validation of this model on the laboratory creep tests is very satisfactory. Furthermore, the activation energy seems satisfactory to represent the influence of the temperature. The in-situ behaviour modelling is clearly more complex than the modelization based on laboratory tests. In fact, it seems that if the rock salt behaviour is maintained by J.LEMAITRE law, it is necessary to vary with the stress, at least, one of the parameters assumed constant in the basic law.  相似文献   

图像平滑算法比较研究及改进策略   总被引：9，自引：0，他引：9  

秦志远 吴冰王艳  山海涛 《测绘学院学报》2005,22(2):103-106

图像平滑作为去除图像中含有噪声的图像增强处理技术，是各种与图像有关软件中必不可少的功能模块。文中在分析噪声模型的基础上，对均值平滑、中值平滑、边缘保持平滑等技术从图像处理空间域中的算法原理、实现方法及效率等方面进行了详细比较。针对图像中含有的不同噪声模型，通过多次试验，得出了值得从事图像处理研究者参考的结论。这将有助于提高图像处理软件开发的效率。  相似文献   

内陆盆地的盐分布与平衡分析研究   总被引：9，自引：0，他引：9       下载免费PDF全文

董新光  姜卉芳  邓铭江  周金龙 《水科学进展》2005,16(5):638-642

在总结已有研究成果和系统分析水文、土壤、灌溉、水盐监测资料的基础上,应用系统分析方法、水盐运移理论和水盐平衡原理,通过对盆地、流域、灌区、农田和土壤剖面等不同层次盐分分布与盐平衡分析计算,分析了内陆盆地不同层次的“干排盐”形成与特征,认为干排盐是必不可少的,必须系统地考虑不同层次干排盐出路与动力条件,才能有效地治理灌区盐渍化问题。  相似文献   

冻融作用对地气系统能量交换的影响分析   总被引：7，自引：12，他引：7  

李述训  南卓铜  赵林 《冰川冻土》2002,24(5):506-511

通过对温度波在地层内传播过程问题的分析研究, 讨论土在冻结和融化过程对地气系统能量交换的影响, 并以亚粘土为例应用近似方法计算了在冻结和融化过程地气系统能量交换和地温变化特征, 同时将相同条件下发生冻融作用与不发生冻融作用情况地气系统热交换量进行了比较. 结果表明, 冻融作用使地气系统热交换加强, 同时吸热和放热的过程也发生了改变.  相似文献   

质量传输和同位素交换:流动几何学和交换机制     

刘伟 《地学前缘》2002,9(4):423-428

耦合的质量传输和动力学限制的同位素交换模型综合考虑了平流、扩散、热液弥散 ,以及岩石与水之间的不平衡同位素交换等项因素。把耦合模型应用于 2个构造环境下的古热液系统 ,进而解释稳定同位素数据。对于造成环绕浅成侵入岩体分布的18O亏损环带的流体的流动几何学 ,以及浅部正断层流体流动的几何学 ,耦合模型提供了不同于单一同位素交换模型的解释。耦合模型也提供了关于同位素相对交换速率和同位素交换机制的信息。结果表明 ,断层带的动态重结晶促进了表面反应 ,进而便利了同位素交换 ;在化学不反应性和未变形的矿物中 ,同位素交换可能受制于固态条件下的扩散。  相似文献   

Evapotranspiration from citrus trees growing in sandy soilunder drip irrigation with saline water     

杨胜利  Tomohisa Yano 《中国科学D辑(英文版)》2002,45(Z1)

An experiment on evapotranspiration from citrus trees under irrigation with saline waterwas carried out for 4 months. Two lysimeters planted with a citrus tree in the green house wereused. One lysimeter was irrigated with saline water (NaCl and CaCl2 of 2000 mg/L equivalence,EC = 3.8 dS/m, SAR = 5.9) and the other was irrigated with freshwater using drip irrigation. Theapplied irrigation water was 1.2 times that of the evapotranspiration on the previous day.Evapotranspiration was calculated as the change in lysimeter weight recorded every 30 minutes.The lysimeters were filled with soil with 95.8% sand. The results of the experiment were as follows.(i) The evapotranspiration from citrus tree was reduced after irrigation with saline water. Theevapotranspiration returns to normal after leaching. However it takes months to exhaust the saltfrom the tree. ( ii ) To estimate the impact of irrigation with saline water on the evapotranspirationfrom citrus trees, the reduction coefficient due to salt stress (Ks) was used in this experiment.Evapotranspiration under irrigation with saline water (ETs) can be calculated from evapotranspira-tion under irrigation with freshwater (ET) by the equation ETs = Ks× ET. Ks can be expressed as afunction of ECsw. (iii) The critical soil-water electrical conductivity (ECsw) is 9.5 dS/m, beyondwhich adverse effects on evapotranspiration begin to appear. If ECsw can be controlled at below9.5 dS/m, saline water can be safely used for irrigation.  相似文献