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161.
Deep Quaternary groundwater is the main source for industrial, domestic, and agricultural water supply in the North China Plain (NCP). There is currently a regional decline of groundwater levels, deterioration of water quality and environmental geological problems induced by increasing exploitation of the NCP Quaternary aquifer system. To trace sources and transport processes of dissolved Cl− in a regional aquifer system and to reveal hydrogeological characteristics of Quaternary complexes, δ37Cl, δ18O and δD, and chemical compositions (including F−, Cl−, Br−) of the deep groundwater sampled from the northern flow system of the NCP were measured along the west–east groundwater flow paths. The measured δ37Cl values decreased from 0.39‰ to −2.22‰ (SMOC) along the groundwater flow direction, with increasing Cl− concentrations. Marine aerosol input via rainfall is the main source of Cl− in the deep groundwater near the recharge areas, and subsequent evaporation/evapotranspiration appears to be responsible for Cl− accumulation. Mixing of recharge water with water of high-Cl− and low-δ37Cl accounts for the pattern of δ37Cl and Cl− concentration observed in Aquifer-3 along the west–east transect. The water with high-Cl and low-δ37Cl is likely from pore water released from compacted clays induced by over-exploitation of deep groundwater, suggesting that clay is a dominant subsurface source of Cl− for groundwater where a regional depression cone is present in the Quaternary aquifers. The groundwater of Aquifer-4 in the Huang-Hua depression is potentially mixed with an upward flux of Cl− from the Neogene aquifer through subvertical faults. Diffusion and ion filtration are two mechanisms invoked to explain the highly negative δ37Cl data for groundwater of Aquifer-4 in the Yanshan–Haixing areas, which provides new insight into solute migration and the hydraulic relationship in the strongly exploited groundwater system. This study using the conservative solute Cl− provides additional important information for further investigations of the geochemistry of a wide range of reactive solutes in the Quaternary aquifer system, so guiding water resource management. 相似文献
162.
以含钙聚合铝(PACCa)作为导向剂与铝源,在常温常压下合成了微/纳结构(微米/纳米尺度)的弗雷德盐。当水溶液中的ρ(Cu2+)为4.406 mg/L时,每升含铜溶液投入0.45 g弗雷德盐对Cu2+的去除率为99.02%。背散射(BEI)与二次电子(SEI)的SEM研究表明:微/纳结构的弗雷德盐在水处理中经历了溶解-结晶过程,XRD鉴定证实弗雷德盐分解后形成方解石晶体与无定形氧化铝。微/纳结构的弗雷德盐去除Cu2+的絮凝沉淀机理与吸附反应模式有所不同,弗雷德盐在絮凝过程中与水中CO2作用转变成方解石与无定形氧化铝,同时Cu2+在碱性环境下生成氢氧化物,新生成的无定型氢氧化铝迅速吸附铜的氢氧化物并裹挟方解石沉淀。 相似文献
163.
根据地震动态触发理论,计算了2000年苏门答腊MS8.0,地震在缅甸MS6.5地震破裂面上产生的动态库仑应力:正峰值为1.357 5 MPa,负峰值为-1.113 5 MPa。峰值大于地震触发阈值0.01 MPa,苏门答腊地震的发生对缅甸地震具有一定的触发作用。在计算过程中发现,主震基本参数、传播过程中介质参数和被触发地震断层参数的准确性对计算结果有较大影响。 相似文献
164.
广东从化石岭碱性杂岩的岩石学特征及其地质意义 总被引:5,自引:2,他引:5
对广东从化石岭碱性杂岩体进行了1:1万地质调查和填图,并进行了详细的岩石力学研究。其结果表明:杂岩体由霞石角闪石正长岩、角闪石正长岩、墨云母正长岩等岩性组成,为A-型花岗岩的分异结晶作用所形成,产于板内引张构造环境,与深大断裂有关。岩体本身已构成霞石正长岩矿床,具有较高的工业利用和经济价值。 相似文献
165.
166.
167.
全国第二次土地调查数据库利用以后,城市建设用地审批、大型的线状用地、土地复垦、矿山治理等工程的前期可研及预审工作等基本都以二调数据为基础数据。将正确的用地红线用ArcGis软件处理成面文件(.Shp),然后把处理后的.shp文件复制到二调数据库里的KCDJ层里。再使用农村土地调查专用软件导出各级用地面积汇总表。通过文中介绍的方法,可以实现快速、准确的制作指定范围的各种地类面积表。 相似文献
168.
169.
Ultrahigh-pressure metamorphism in the forbidden zone: the Xugou garnet peridotite, Sulu terrane, eastern China 总被引:21,自引:3,他引:21
The Xugou garnet peridotite body of the southern Sulu ultrahigh‐pressure (UHP) terrane is enclosed in felsic gneiss, bounded by faults, and consists of harzburgite and lenses of garnet clinopyroxenite and eclogite. The peridotite is composed of variable amounts of olivine (Fo91), enstatite (En92?93), garnet (Alm20?23Prp53?58Knr6?9Grs12?18), diopside and rare chromite. The ultramafic protolith has a depleted residual mantle composition, indicated by a high‐Mg number, very low CaO, Al2O3 and total REE contents compared to primary mantle and other Sulu peridotites. Most garnet (Prp44?58) clinopyroxenites are foliated. Except for rare kyanite‐bearing eclogitic bands, most eclogites contain a simple assemblage of garnet (Alm29?34Prp32?50Grs15?39) + omphacite (Jd24?36) + minor rutile. Clinopyroxenite and eclogite exhibit LREE‐depleted and LREE‐enriched patterns, respectively, but both have flat HREE patterns. Normalized La, Sm and Yb contents indicate that both eclogite and garnet clinopyroxenite formed by high‐pressure crystal accumulation (+ variable trapped melt) from melts resulting from two‐stage partial melting of a mantle source. Recrystallized textures and P–T estimates of 780–870 °C, 5–7 GPa and a metamorphic age of 231 ± 11 Ma indicate that both mafic and ultramafic protoliths experienced Triassic UHP metamorphism in the P–T forbidden zone with an extremely low thermal gradient (< 5 °C km?1), and multistage retrograde recrystallization during exhumation. Develop of prehnite veins in clinopyroxenite, eclogite, felsic blocks and country rock gneiss, and replacements of eclogitic minerals by prehnite, albite, white mica, and K‐feldspar indicate low‐temperature metasomatism. 相似文献
170.
Summary Formulation and case studies of a three dimensional kinematic model are presented. Thein situ overburden geometry can be simulated accurately and various initiation patterns of blasts can be modelled. The overburden geometry, hole patterns and explosive distribution are all explicit model inputs. Because the effect of explosive properties, rock mass condition and inter-row delay are very difficult to measure in terms of blast performance, these are represented in the model by control parameters which are left for calibration using field data. The output of the model is a three dimensional muckpile shape of any cross section and a contour map of grade distribution within the muckpile. Two case studies are presented which have shown that the model is a valuable tool for optimizing production blasting as well as for controlling grade dilution during blasting. 相似文献