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根据水文观测和引水与水电开发资料,分析了大通河流域水能水资源开发利用现状及其对河流水文过程与生态环境的影响.结果表明:由于区域用水和跨流域引水,使大通河中下游河道的水量减少,水环境容量减小,其中,青石嘴、天堂、连城(二)站3-11月平均流量分别减少0.6%~9.6%、0.5%~3.8%、1.7%~52.9%. 自1994年引大入秦工程建成跨流域引水后,连城(二)站年径流量开始减少,1994-2010年平均径流量比1977-1993年减少了5.7%;引大济湟工程建成通水后,加上引大入秦和引硫济金工程,引水总量将达到12.33×108 m3,占大通河多年平均径流量28.16×108 m3的43.8%,对河川径流的影响十分显著. 至2011年,大通河上已建成梯级电站34座,洪水期电站同时泄水会瞬间加大河道流量,枯水期蓄引水又使减水河段水量减少. 梯级水电站群无序蓄放水使洪水过程由天然的平稳状态转变为人工干预的剧烈变化状态,上下游洪峰不对应,对下游地区的防洪安全产生极大威胁. 过度的水能水资源开发,使大通河中下游部分自然河段出现淹没、断流,水生物和两岸的植物萎缩,水环境污染加重,对生态环境产生负面影响. 建议实行流域水资源统一管理,对梯级电站下泄水量统一调度,在减水河段预留必须的生态基流,确保河道内外生态用水;加强河道水位、流量、泥沙、水环境、水生物监测,为流域防汛、水资源管理、生态环境保护等提供决策依据. 相似文献
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Iron and manganese redox cycling in the sediment — water interface region in the Kalix River estuary was investigated by using sediment trap data, pore-water and solid-phase sediment data. Nondetrital phases (presumably reactive Fe and Mn oxides) form substantial fractions of the total settling flux of Fe and Mn (51% of Fetotal and 84% of Mntotal). A steady-state box model reveals that nondetrital Fe and Mn differ considerably in reactivity during post-depositional redox cycling in the sediment. The production rate of dissolved Mn (1.6 mmol m–2 d–1) exceeded the depositional flux of nondetrital Mn (0.27 mmol m–2 d–1) by a factor of about 6. In contrast, the production rate of upwardly diffusing pore-water Fe (0.77 mmol m–2 d–1) amounted to only 22% of the depositional flux of nondetrital Fe (3.5 mmol m–2 d–1). Upwardly diffusing pore-water Fe and Mn are effectively oxidized and trapped in the oxic surface layer of the sediment, resulting in negligible benthic effluxes of Fe and Mn. Consequently, the concentrations of nondetrital Fe and Mn in permanently deposited, anoxic sediment are similar to those in the settling material. Reactive Fe oxides appear to form a substantial fraction of this buried, non-detrital Fe. The in-situ oxidation rates of Fe and Mn are tentatively estimated to be 0.51 and 0.16–1.7 mol cm–3 d–1, respectively. 相似文献
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Doklady Earth Sciences - Experimental data are presented to show that the spatial and temporal variability of the composition of river waters cannot be explained solely by the influence of sources... 相似文献
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塔北天然气组分特征及同位素组成 总被引:1,自引:0,他引:1
通过对塔北天然气32个样品的化学组分特征,甲烷的碳、氢同位素组成及关系,以及单烃碳同位素系列特征,甲烷的碳同位素组成与烃类组分关系等方面的综合研究揭示了塔北不同油气区不同井位天然气的成因类型以及某些井位天然气的来源,为塔北油气勘探提供了有价值的信息。 相似文献
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R. L. Romer 《Mineralogy and Petrology》1994,50(4):271-285
Summary Proterozoic sulfide deposits within the basement of northern Sweden have lead isotopic compositions that fall on a mixing line in the206Pb/204Pb-207Pb/204Pb diagram. These deposits contain a highly radiogenic Phanerozoic lead component that was leached from the Proterozoic basement at around 0.4 Ga during the Caledonian orogeny. Within the Proterozoic deposits, the less radiogenic lead isotopic compositions occur in undeformed and little deformed sections, while the more radiogenic lead isotopic compositions are observed along fault, fracture, and shear zones. These zones with radiogenic Phanerozoic lead also have higher contents of lead, zinc, and gold, respectively, than the other parts of the deposits, which suggests that these metals were introduced together with the radiogenic lead at a much later event than the metals in the unaltered Proterozoic deposit. The Proterozoic deposits acted as traps for metal additions along Caledonian reactivated fault and shear zones in the Proterozoic basement.
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Kaledonische Metallanreicherung in niedrighaltigen proterozoischen Buntmetallerzen in Nordschweden
Zusammenfassung Proterozoische Sulfidvererzungen im proterozoischen Grundgebirge weisen Bleiisotopenzusammensetzungen auf, die auf eine Mischungslinie im206Pb/204Pb-207Pb/204Pb Diagramm fallen. Die proterozoischen Vererzungen enthalten eine Komponente radiogenen Bleis, welches im Verlaufe der kaledonischen Orogenese aus dem proterozoischen Grundgebirge ausgelaugt wurde. Wenig oder nicht deformierte Abschnitte in den proterozoischen Sulfidvererzungen weisen weniger radiogene Bleiisotopenzusammensetzungen auf, als Bruch- und Scherzonen in denselben Vererzungen. Diese Zonen mit radiogenem, kaledonischem Blei weisen auch höhere Blei-, Zink- und Gold-Gehalte auf als die übrigen Teile der Vererzung, was andeutet, daß diese Metalle zusammen mit dem radiogenen Blei zu einem viel späteren Zeitpunkt in die Vererzung eingebracht worden sind. Die proterozoischen Vererzungen bewirkten die Metallausfällung aus Fluiden, die entlang von kaledonisch mobilisierten Verwerfungen und Scherzonen flossen.
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B. Öhlander 《Mineralium Deposita》1985,20(4):241-248
The largest known Precambrian molybdenite occurrences in Sweden are of the aplitic type. In order to improve the understanding of their genesis, 67 samples of aplites, aplitic granites and associated granites were analyzed for major elements, Mo, Sn, Be, Ba, Rb, Sr, Cu, Zn, Zr, V, Cr, Ni, Y, Nb, F, Cl and S. Five samples were analyzed for rare earth elements. The following genetic model can be proposed:In the upper parts of granitic intrusions the magma is enriched in lithophile elements and elements such as F and Mo. The aplites represent direct differentiation products of the granites and have solidified without the development of a second mobile aqueous phase, except locally, where small pegmatite segregations have formed. As crystallization proceeds, the concentration of Mo in the magma increases, and when the aplites solidify, the Mo that cannot be incorporated in the rock-forming minerals is precipitated as molybdenite. Biotite seems to be the major Mo-carrier among the rock-forming minerals in the aplites. 相似文献
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滏阳河上游岩溶水的开发利用及其对环境的影响 总被引:2,自引:0,他引:2
分析了滏阳河上游黑龙洞泉域地下水水资源补给成因,以及大量开采岩溶水对水量、水质及周边环境的影响。黑龙洞泉域地下水补给成因主要包括近3年降水和部分河渠渗漏。泉域上游开采量的不断增大造成泉群溢出量逐年减少,并对周边生态环境和人民生活产生了一定影响。 相似文献
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水资源承载能力制约和决定了经济社会可持续发展,拓展提高水资源承载能力,能为经济社会可持续发展提供更大的水资源支撑空间。黄河两岸的浅层地下水含水层,具备相当大的蓄储调蓄功能,形成了巨大的地下水库。计算结果显示,在原有水资源总量不增加的情况下,运用地下水库调蓄黄河水和大气降水,使得中原沿黄经济带2020年75%、90%年型的缺水率从11.4%、21.7%下降为0.5%和2.1%。采用地下水库调蓄很大程度上减少了中原沿黄经济带水资源开发利用的缺水率,使该地区的水资源承载能力大大提高。 相似文献
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唐河流域水利水电资源开发利用存在的问题及对策 总被引:3,自引:0,他引:3
唐河流域位于山西省北部,通过浑源、灵丘两县,汇入河北省大清河。境内流域面积2071km^2,水资源总量2.134亿m^3。根据该流域水土资源的时空分布特点,本文就境内流域水利水电资源开发利用中存在的问题,提出了解决的对策和充分利用水电资源的途径。 相似文献
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黑河流域水资源系统演变和人类活动影响 总被引:4,自引:0,他引:4
黑河流域降水集中于山区,平原稀少。50多年来,除了20世纪70—80年代上游的中东部地区降水偏多外,其它区域为正常变化;蒸发量从山区向平原逐渐增大,除了中游蒸发量显示稳定变化外,山区和下游区表现为减少趋势;黑河多年出山径流量呈现稳定变化,但在中下游盆地间的正义峡水文站,径流量自20世纪80年代中期以来,出现了非常明显的减少过程:这是受到中游地区地下水开采量增加、补给量减少和水位下降的影响,主要是中游地区人口数量增多、大规模扩耕灌溉和水工建设作用的结果。计算表明,人类活动影响强度:20世纪50年代占18%,60—70年代占28%,80—90年代占54%;上游占1%,中游占87%,下游占12%。这说明黑河中游80—90年代是人类活动影响强度达到最大的地区。因此,提出了充分认识流域水资源系统演变规律性,约束人类活动的影响,均衡保护利用流域水资源的有关建议。 相似文献
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以洮河干流站实测水温、冰情资料为依据,采用相关分析、线性回归的方法分析水电站建设前上下游站水温年序列关系和冰情发生和消失之间的对应规律,进而研究水电站建设后河流水温及冰情的变化情况.分析结果表明:水电站建设对河流热状况的影响明显,引蓄水大坝下游各站的年平均水温升高了0.5℃,上半年冰情提前结束,下半年冰情推后出现,封冻现象完全消失. 相似文献
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众多研究表明黄河源区受气候变化影响,土壤活动层逐渐下降。土壤温、湿度是陆面过程及地球系统中的重要物理量,它们通过影响地表能量和物质交换而影响大气环流和降水等。利用WRF(Weather Research and Forecasting)模式,选取2个典型年分别设计了2个控制试验和2个敏感性试验来探讨土壤初始状况变化对区域水循环的影响,通过再循环降水率定量描述不同气候背景下陆面对黄河源区水循环的影响,并尝试从环流角度进一步分析土壤初始状况改变对源区水循环影响的物理机制。结果表明:陆面对水循环的影响受大尺度环流背景场影响较大,较弱的环流背景下再循环降水率较强环流背景大5%左右。土壤初始状况对水循环要素有一定程度的影响。土壤初始温度升高/降低,水汽通量增多/减少,后期降水增大/减小。不同环流背景下,土壤记忆时间不同,在弱的环流背景下,土壤记忆时间要长,初始状况扰动可持续1~2个月。 相似文献
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Stable Isotope Composition of Rainfall,Surface Water and Groundwater along the Yellow River 下载免费PDF全文
The intention of this work is to consider the stable isotopic compositions of oxygen and deuterium in rainfall, surface water and groundwater along the Yellow River in the North China Plain (NCP). This demonstrated that the δ18O values in groundwater varied from –10.17 to –6.85‰, with mean value of –8.76‰, and that the δD ranged from –68.7 to –58.0‰, with mean value of –63.4‰, respectively. The δ18O values in surface water varied from –8.36 to 1.32‰, with mean value of –6.8‰, and δD ranged from –64.4 to –35.1‰, with mean value of –57.6‰, respectively. Further, The range of Cl- values of groundwater varied from 5.9 to 340.5 mg/L and that values ranged from 30.1 to 81.9 mg/L in surface water samples and Na+ value changed from 27.4 to 321 mg/L in groundwater, while that in surface water varied from 24.8 to 50.5 mg/L. Most of the points fall below the GMWL?, but are close to the LMWL.? Therefore the results indicated that the groundwaters along the Yellow River were influenced by rainfall in heavy events and surface water. 相似文献
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《Precambrian Research》1986,32(1):35-44
Three types of zircons from an albite diabase sill within the Kiruna Greenstone Group have been investigated to determine their age and order of crystallization. The youngest, pink and transparent zircons probably crystallized in late fissures and in association with a thermal event. The intermediate, white zircon populations could not be readily dated because of significant lead loss. The lead 207/206 ages of both the pink and white zircons agree roughly with that of the Sm-Nd isochron (about 1.93 Ga) on secondary minerals from a Kiruna greenstone (Skiöld and Cliff). The oldest, brown zircons indicate an age of about 2.2 Ga, and probably reflect the initial crystallization of the rock. The formation of the early Proterozoic greenstones in the Kiruna area thus commenced about 2.2 Ga ago or earlier. These results are consistent with the proposed chronostratigraphy of the Jatulian formations in Finland (e.g., Simonen; Meriläinen). A time interval of at least 0.3 Ga is assumed for the volcano-sedimentary period which pre-dates the Svecokarelian orogeny of the Kiruna area. 相似文献