苏北盆地高邮凹陷始新统戴南组一段稀土元素特征及其物源指示意义   总被引：1，自引：0，他引：1  

张妮  林春明  周健  陈顺勇  刘玉瑞  董桂玉 《地质论评》2012,58(2):369-378

稀土元素(REE)的物源对比表明,苏北盆地高邮凹陷戴南组一段沉积岩的物源以其西侧张八岭隆起的元古宙浅变质岩基底为主,并与大别和苏鲁造山带的浅变质岩基底存在亲缘关系,推断研究区的母岩类型为高钾I型花岗片麻岩。而张八岭隆起的新元古代细碧—石英角斑岩和绿片岩、中生代火成岩、大别山南部大范围的榴辉岩以及宁镇山脉的中生代中酸性侵入岩对研究区的物源影响很小。在高邮凹陷内部的物源方向分析中,轻重稀土元素分馏值[(La/Yb)N]与矿物成熟度指数(MMI)形成很好的吻合,(La/Yb)N值结合稀土元素总量(∑REE)及铕异常值(δEu)可对研究区内物源方向的精确判别具有指示意义。戴南组一段沉积时期,高邮凹陷的物源主要来自4个方向:西北部柘垛低凸起方向、东部吴堡低凸起方向、南部通扬隆起方向和西南部菱塘桥低凸起方向。高邮凹陷戴南组一段的沉积相类型与REE特征的相关性分析显示,重稀土元素分馏值[(Gd/Yb)N]与沉积相间存在较为规律的变化,表现在近岸水下扇相、扇三角洲相和三角洲相随其碎屑岩的成熟度升高,(Gd/Yb)N平均值呈逐渐升高的趋势,该趋势同样表现在相同沉积相的不同沉积亚相之间,说明(Gd/Yb)N平均值可较好地反映沉积相特征。  相似文献   

Hydrochemical characteristics of irrigation return flow in semi-arid regions of Iran     

H. Jafari  E. Raeisi  M. Zare 《水文科学杂志》2013,58(1):173-185

Abstract

The study area is located on the Harat plain, in the central region of Iran. Four local-soil filled, free-drainage lysimeters were installed in wheat and barley farms operating under traditional farm management practices. The volume, electrical conductivity (EC), nitrate and major ions of the applied irrigation water and irrigation return flow (IRF) were measured during the growing season. The total dissolved solids (TDS) of IRF increased three to five times compared to that of the applied water. This enhancement was the same as for the chloride ion ratio, indicating the major impact of evapotranspiration in IRF salinity enhancement. Geochemical modelling using PHREEQCI confirmed the significant role of evapotranspiration and the minor effects of processes such as calcite precipitation, gypsum dissolution, fertilizer nitrification and ion exchange on the values of the IRF TDS. Time variations of EC were functions of the type of flow (preferential or matrix), lithology and soil type. The controlling parameters of the nitrate time series were the frequent applications of N fertilizer and the nitrification process. The annual N loads (NO₃-N) of IRF varied from 22 to 195 kg ha^-1. These variations were due to the different N loads in the applied water, the amount of fertilizer, soil texture, N uptake and volume of IRF. The annual salt loads of IRF were mainly controlled by the volume of IRF.

Editor Z.W. Kundzewicz

Citation Jafari, H., Raeisi, E., Hoehn, E. and Zare, M., 2012. Hydrochemical characteristics of irrigation return flow in semi-arid regions of Iran. Hydrological Sciences Journal, 57 (1), 173–185.  相似文献   

北极新奥尔松地区夏季近地面CO₂、CH₄和N₂O浓度的观测研究          下载免费PDF全文

陈清清  朱仁斌  徐华 《极地研究》2013,25(2):150-160

2008和2009年夏在北极新奥尔松地区（Ny-Ålesund）不同苔原区域（鸟类保护区、海滩苔原、矿区、人类活动区等）监测CO₂、CH₄和N₂O近地面浓度的时空变化并分析其可能的影响因素。2008年7月25日-8月13日和2009年7月13-26日,在不同观测区域设置常规和非常规采样点采集气体样品共239瓶并妥善保存。实验室内使用气相色谱（GC）测定准确真空瓶中温室气体（CO₂、CH₄和N₂O）的浓度。鸟类保护区的日变化中,2008年鸟类保护区CO₂和N₂O日变化浓度均大于2009年约30 ppm和25 ppb。2008年海滩苔原CO₂浓度均高于2009年约30 ppm;N₂O浓度低于2009年11 ppb;2008年鸟类保护区CH₄浓度低于2009年,而海滩苔原2008年浓度高于2009年,差值均约为0.7 ppm。这些年际变化可能由环境条件（天气变化等）和地表覆盖情况的变化引起。高海鸟活动区（HB）CO₂浓度低于海鸟活动较少的区域（MB 和 LB）;鸟类保护区CO₂浓度低于海滩苔原,N₂O浓度高于海滩苔原,主要原因是海鸟活动和鸟粪增加了土壤营养元素,影响苔藓植被发育的情况并改变上垫面状况。综合不同苔原区域：新奥尔松地区CO₂和CH₄浓度高于ZEP (Zeppelin Station)监测平均浓度,地表向大气输送CO₂和CH₄;而N₂O低于ZEP监测的平均浓度,地表从大气吸收N₂O。不同区域影响因素不同：鸟类保护区、海滩苔原和鸟岛主要是受到海鸟活动影响;矿区主要是受水分和土壤基质影响;站区和机场受到人类活动影响但并不明显,总的来说直接原因是由于地表覆盖情况以及地形不同引起。  相似文献   

模拟^15N在半干旱草原中的迁移     

曾晶  杨玉盛  程栋梁  张滨泓 《福建地理》2013,(3):52-58

本研究探讨地上、地下植物氮循环周期的改变如何影响地上植物的氮含量．用2个模拟实验分别探讨模拟地上植物氮库与地上、地下植物氮库循环周期的关系以及地上植物氮库与地上、地下植物氮交换的关系,是对Dijkstra模型的延伸和补充．模拟实验说明在植物与微生物存在氮竞争的情况下,会促使地上植物氮库短期迅速增长,但从长期来看仍保持不变．实验还说明地上、地下植物氮之间的再吸收、再转移的极端情形对地上植物中氮含量的长期影响非常小,但这些效果在短期是可观的．  相似文献   

Using landscape characteristics to define an adjusted distance metric for improving kriging interpolations     

Steve W. Lyon  Rasmus S⊘rensen  Johan Stendahl  Jan Seibert 《International journal of geographical information science》2013,27(5):723-740

Interpolation of point measurements using geostatistical techniques such as kriging can be used to estimate values at non-sampled locations in space. Traditional geostatistics are based on the spatial autocorrelation concept that nearby things are more related than distant things. In this study, additional information was used to modify the traditional Euclidean concept of distance into an adjusted distance metric that incorporates similarity in terms of quantifiable landscape characteristics such as topography or land use. This new approach was tested by interpolating soil moisture content, pH and carbon-to-nitrogen (C:N) ratio measured in both the mineral and the organic soil layers at a field site in central Sweden. Semivariograms were created using both the traditional distance metrics and the proposed adjusted distance metrics to carry out ordinary kriging (OK) interpolations between sampling points. In addition, kriging with external drift (KED) was used to interpolate soil properties to evaluate the ability of the adjusted distance metric to incorporate secondary data into interpolations. The new adjusted distance metric typically lowered the nugget associated with the semivariogram, thereby better representing small-scale variability in the measured data compared to semivariograms based on the traditional distance metric. The pattern of the resulting kriging interpolations using KED and OK based on the adjusted distance metric were similar because they represented secondary data and, thus, enhanced small-scale variability compared to traditional distance OK. This created interpolations that agreed better with what is expected for the real-world spatial variation of the measured properties. Based on cross-validation error, OK interpolations using the adjusted distance metric better fit observed data than either OK interpolations using traditional distance or KED.  相似文献   

A detailed study of G35.2–0.7N: collimated outflows in a cluster of high-mass young stellar objects     

A. G. Gibb  M. G. Hoare  L. T. Little  M. C. H. Wright 《Monthly notices of the Royal Astronomical Society》2003,339(4):1011-1024

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Elemental and isotopic signatures of particulate organic carbon in the Zengjiang River,southern China     

Quanzhou Gao  Zhen Tao  Guanrong Yao  Jian Ding  Zufa Liu  Kexin Liu 《水文研究》2007,21(10):1318-1327

Riverine total suspended sediment (TSS) at the lower reach section of the Zengjiang River, a low‐turbidity river in the southern China, was sampled on a 4‐week basis from March 2002 to February 2003. The gross TSS was divided into sedimentary and suspended fractions (SED and SUS) by the sedimentation method. Organic carbon and nitrogen, ¹⁴C and ¹³C were analysed using an elemental analyser and accelerator mass spectrometer respectively. The results show that particulate organic carbon (POC) yield is 0·8 × 10⁶ g km^?2 year^?1 in the Zengjiang River drainage basin, which is about one‐tenth of that in the Zhujiang (Pearl) River drainage basin. The C/N ratio demonstrates that aquatic biomass is the major contributor to POC in the Zengjiang River. The average share of aquatic biomass in the SUS‐fraction POC and SED‐fraction POC is about 88·89% and 62·76% respectively, with a substantial seasonal variation. δ¹³C values of SUS‐fraction POC (?26·56 to ? 22·89‰) is slightly lighter than that of SED‐fraction POC (?25·05 to ? 22·20‰), indicating that the contribution of aquatic biomass to δ¹³C values is more pronounced in the SUS‐fraction POC than in the SED‐fraction POC. The ‘bomb’–¹⁴C signature is not detected in the POC of Zengjiang River, and the contribution from geological organic carbon is very little. Δ¹⁴C values of the SED‐fraction POC vary from ? 44 to ? 223‰, and the Δ¹⁴C values of the SUS‐fraction POC vary from ? 33 to ? 165‰. For most paired samples, the SED‐fraction POC is generally more depleted in ¹⁴C than that of its counterpart SUS‐fraction POC. Compared with other small mountainous rivers, the ¹⁴C enrichment of POC in the Zengjiang River indicates slight drainage basin erosion. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

General solution of the Kozai mechanism     

Hiroshi Kinoshita  Hiroshi Nakai 《Celestial Mechanics and Dynamical Astronomy》2007,98(1):67-74

Kinoshita and Nakai (Celest. Mech. Dyn. Astr. 75, 125–147, 1999) gave the analytical solution of the Kozai mechanism. In this solution the eccentricity and the inclination of a disturbed body take any value, but the argument of the pericenter is restricted to take 0° or 90°. In this paper, we derive the general solution that can be applied for any value of the argument of the pericenter.  相似文献   

Optimization of medium and cultivation conditions for enhanced exopolysaccharide yield by marine Cyanothece sp. 113     

苏传东  池振明  卢伟东 《中国海洋湖沼学报》2007,25(4):411-417

Cyanothece sp. 113 is a unicellular, aerobic, diazotrophic and photosynthetic marine cyanobacterium. The optimal medium for exopolysaccharide yield by the strain was 70.0 g/L of NaCl, and 0.9 g/L of MgSO4 based on the modified F/2 medium for cultivation of marine algae. The optimal cultivation condition for exopolysaccharide yield by this cyanobacterial strain was 29°C, aeration, and continuous illumination at 86.0 μE/M2/S. Under the optimal conditions, over 18.4 g/L of exopolysaccharide was produced within 12 days. This was so far the highest exopolysaccharide yield produced with strains of Cyanothece sp. obtained.  相似文献   

A search for interstellar pyrimidine   总被引：1，自引：0，他引：1  

Yi-Jehng Kuan  Chi-Hung Yan  Steven B. Charnley  Zbigniew Kisiel  Pascale Ehrenfreund  Hui-Chun Huang 《Monthly notices of the Royal Astronomical Society》2003,345(2):650-656

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