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91.
浅层地下水补给对人类活动影响的响应特征研究 总被引:3,自引:1,他引:2
本文通过数据整理分析, 查明滹沱河流域平原区1976-2005年以开采量、灌区引水量和河道过水量为代表的人类活动逐渐增强, 分析了浅层地下水补给在大气降水减少和人类活动逐渐增强背景下大幅减少的响应特征: 综合补给量所占比率由1976-1980年的21.6%下降到2000-2005年的11.3%。随后, 从开采量、河道过水量和灌区引水量三个方面分析了浅层地下水补给响应人类活动的变化特征: 地下水补给量与开采量呈y=65.412x-0.2576模式随降水量增减而负相关变化; 河道渗漏补给量和渠水入渗量在地下水位不同埋深条件下表现出随来水量、引水量增加而增大的态势, 但在不同埋深条件下, 河道渗漏补给量与来水量之间、渠水入渗量和引水量之间关系不同。 相似文献
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93.
利用1951—2010年我国江淮流域11个测站夏季(6—8月)降水资料和NCAR提供的北半球月平均海平面气压场资料以及相关的西太平洋副高指数资料,采用Morlet小波变换、交叉小波变换及相关分析等方法讨论了降水准两年振荡现象的年际变化规律及其与东亚夏季风、副高的关系。结果表明,准两年振荡分量在江淮地区夏季降水场的年际振荡中十分重要,且经历了由强到弱再到强的变化过程;同时降水与夏季风强度及副高脊线位置的准两年变化均存在较好的同期相关,彼此间的相互影响还体现在年际尺度上,并分别在4 a和1 a时间尺度上有明显的滞后、超前关系。 相似文献
94.
The Bohai Bay Basin is a classic non-marine rift basin in eastern China. The Paleogene Dongying sequences are the main hydrocarbon-bearing stratigraphic unit in the basin. Using three-dimensional (3-D) seismic data and one well control in the BZ3-1 Block in the western slope of the Bozhong Sag, we analyzed 3-D facies architectures of the Dongying sequences. The Dongying Formation, a second-order sequence, can be subdivided into four third-order sequences (from base to top: SQ1, SQ2, SQ3, and SQ4). The facies architecture was analyzed by using the seismic sedimentology approach based on 3-D seismic data. Sediment of the Dongying sequences was derived from the northern Shijiutuo Uplift via four major configurations of incised valleys, namely “V”, “U”, “W”, and composite shaped incised valleys. Seismic stratal slices reveal branching and converging characteristics of the channels from upstream to downstream. On the basis of an integrated analysis of well log, core data, seismic facies based on multi-seismic attributes, three sedimentary facies (e.g., “delta”, “fan-delta”, and “shore” or “shallow lacustrine” facies) have been recognized. The four types of incised valleys and their evolution control the sedimentary systems in the sedimentation area. The numbers and sizes of the fans are controlled by the sedimentary systems at various scales. Incised valley-fill and deltaic sand bodies are excellent hydrocarbon reservoirs and potentially good exploration targets for the study area. The reservoir quality of sequences SQ1, SQ2, and SQ3 become better gradually from base to top. The proposed sediment dispersal patterns may aid in the prediction of potential reservoir distribution. This study also demonstrates that facies architecture analysis using sequence stratigraphy and seismic sedimentology may serve as an effective approach for constructing 3D facies models for petroleum exploration in areas lacking of well or outcrop data. 相似文献
95.
相干能量梯度体现了相干数据的振幅变化,它比较有利于突出一些细小的地质特征变化,其属性比例融合是将两个数据体按照一定比例融合在一起生成新的数据体,而新数据体能更好的反映地质特征。实例表明,与相干属性相比,相干能量梯度属性对一些细小构造更敏感,而且可以根据不同方向、时间的切片对不同走向的断层进行追踪;与常规地震时间剖面相比,属性比例融合后的属性剖面,可以在剖面中显示两种属性体的断裂构造特性,减少单一属性体的不确定性。 相似文献
96.
Noel P. James Margaret J. Seibel Robert W. Dalrymple David Besson Olivier Parize 《Sedimentology》2014,61(2):497-534
The Saumane‐Venasque compound palaeovalley succession accumulated in a strongly tide‐influenced embayment or estuary. Warm‐temperate normal marine to brackish conditions led to deposition of extensive cross‐bedded biofragmental calcarenites. Echinoids, bryozoans, coralline algae, barnacles and benthic foraminifera were produced in seagrass meadows, on rocky substrates colonized by macroalgae and within subaqueous dune fields. There are two sequences, S1 and S2, the first of which contains three high‐frequency sequences (S1a, S1b and S1c). Sequence 1 is largely confined to the palaeovalley with its upper part covering interfluves. Each of these has a similar upward succession of deposits that includes: (i) a basal erosional surface that is bored and glauconitized; (ii) a discontinuous lagoonal lime mudstone or wackestone; (iii) a thin conglomerate generated by tidal ravinement; (iv) a transgressive systems tract series of cross‐bedded calcarenites; (v) a maximum flooding interval of argillaceous, muddy quartzose, open‐marine limestones; and (vi) a thin highstand systems tract of fine‐grained calcarenite. Tidal currents during stages S1a, S1b and S1c were accentuated by the constricted valley topography, whereas basin‐scale factors enhanced tidal currents during the deposition of S2. The upper part of the succession in all but S1c has been removed by later erosion. There is an overall upward temporal change with quartz, barnacles, encrusting corallines and epifaunal echinoids decreasing but bryozoans, articulated corallines and infaunal echinoids increasing. This trend is interpreted to be the result of changing oceanographic conditions as the valley was filled, bathymetric relief was reduced, rocky substrates were replaced as carbonate factories by seagrass meadows and subaqueous dunes, and the setting became progressively less confined and more open marine. These limestones are characteristic of a suite of similar cool‐water calcareous sand bodies in environments with little siliciclastic or fresh water input during times of high‐amplitude sea‐level change wherein complex inboard antecedent topography was flooded by a rising ocean. 相似文献
97.
A‐Juan Pang Sheng‐Rong Li M. Santosh Qing‐Yu Yang Bao‐Jian Jia Cheng‐Dong Yang 《Geological Journal》2014,49(1):52-68
The Jilongshan skarn Cu–Au deposit is located at the Jiurui ore cluster region in the southwestern part of the Middle–Lower Yangtze River valley metallogenic belt. The region is characterized by NW‐, NNW‐ and EW‐trending faults and the mineralization occurs at the contact of lower Triassic carbonate rocks and Jurassic granodiorite porphyry intrusions. The intrusives are characterized by SiO2, K2O, and Na2O concentrations ranging from 61.66 to 67.8 wt.%, 3.29 to 5.65 wt.%, and 2.83 to 3.9 wt.%, respectively. Their A/CNK (A/CNK = n(Al2O3)/[n(CaO) + n(Na2O) + n(K2O)]) ratio, δEu, and δCe vary from 0.77 to 1.17, 0.86 to 1, and 0.88 to 0.96, respectively. The rocks show enrichment in light rare earth elements ((La/Yb)N = 7.61–12.94) and large ion lithophile elements (LILE), and depletion in high field strength elements (HFSE), such as Zr, Ti. They also display a peraluminous, high‐K calc‐alkaline signature typical of intrusives associated with skarn and porphyry Cu–Au–Mo polymetallic deposits. Laser ablation inductively coupled plasma spectrometry (LA‐ICP‐MS) zircon U–Pb age indicates that the granodiorite porphyry formed at 151.75 ± 0.70 Ma. A few inherited zircons with older ages (677 ± 10 Ma, 848 ± 11 Ma, 2645 ± 38 Ma, and 3411 ± 36 Ma) suggest the existence of an Archaean basement beneath the Middle–Lower Yangtze River region. The temperature of crystallization of the porphyry estimated from zircon thermometer ranges from 744.3 °C to 751.5 °C, and 634.04 °C to 823.8 °C. Molybdenite Re–Os dating shows that the Jilongshan deposit formed at 150.79 ± 0.82 Ma. The metallogeny and magmatism are correlated to mantle–crust interaction, associated with the subduction of the Pacific Plate from the east. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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99.
根据对马超营断裂带系统进行的地质—地球化学剖面研究,探讨了该带断裂构造活动及其元素地球化学迁移富集规律与构造地球化学分异之间的关系;分析了蚀变、矿化与成矿的关系,认为早期面型蚀变伴有成矿元素的活化和迁移,但无矿化富集,后期带状蚀变伴有金的富集成矿且以硅化、绢云母化为主要标志。从而,为马超营断裂带这一重要的以金为主成矿带的进一步工作、研究,提供了地球化学方面的依据。 相似文献
100.
咸阳渭河高漫滩沉积洪水变化研究 总被引:6,自引:0,他引:6
根据咸阳高漫滩XY剖面中116个样品的粒度分析,结合历史文献记载的年代资料得出,渭河约120年来形成的高漫滩洪水沉积分层明显,对洪水的变化反映清楚,分辨率高,能够作为很好地指示洪水变化的指标。XY剖面最上层为2003年大洪水沉积,最上层之下的其它15层为古代洪水发生时期形成的沉积层,整个剖面记录了16次规模较大的洪水。XY剖面随深度变化具有明显的粗细变化节律,其中第1、3、5、7、9、11、13、15层粒度组成较第2、4、6、8、10、12、14、16层细。在充分考虑了因洪水沉积逐步叠加引起的地形增高对粒度成分的影响之后,可以确定这16个阶段洪水深度和规模由大到小的变化顺序为:第12阶段>第15阶段>第6阶段>第9阶段>第16阶段>第1阶段>第5阶段>第14阶段>第7阶段>第11阶段>第3阶段>第13阶段>第8阶段>第10阶段>第4阶段>第2阶段。其中第12、15、6、9、16、1阶段的洪水规模较第5、14、7、11、3、13、8、10、4、2阶段洪水规模更大。根据2003年河漫滩上的洪水沉积层粒度成分和洪水深度为2.2 m左右确定,所研究的剖面中第6、9、12、15、16、1层形成时的河漫滩上的洪水深度大于2.2 m,第5、14、7、11、3、13、8、10、4、2层形成时的洪水深度小于2.2 m。通过与现代大洪水发生时期年降水量的对比可知,这些大洪水发生的主要是渭河流域一些地区当年降水量显著增加造成的。在这16个洪水阶段之间没有洪水发生的阶段是降水量正常或偏少的阶段。 相似文献