皖南地区离子吸附型稀土矿床成矿条件及成矿特征

安徽省皖南地区岩浆岩分布广泛,地貌、气候条件适宜,有利于花岗岩风化壳的形成、保存,且基岩的稀土丰度较高,有利于离子吸附型稀土矿床的形成。通过在皖南地区的工作,分析了离子吸附型稀土矿床的内生成矿条件(基岩中稀土丰度、稀土元素赋存状态、矿物组合及岩石结构、构造),表生成矿条件(气候条件、风化壳发育程度、地貌特征),总结了离子吸附型稀土矿床的成矿特征、找矿标志。     

新集一矿水文工程地质特征及开采条件分析

新集一矿煤炭资源储量丰富,内部构造复杂,矿井突水、涌水灾害时有发生。通过收集新集一矿的钻探地质资料,重点分析13煤层及其顶板水文工程地质条件,并对煤层开采条件进行分析。结果发现:新集一矿13煤附近岩石以及13煤顶板岩石性质总体表现为岩质较软,强度低,割线模量小,地质条件复杂程度为中等型,会偶然受到地热和天窗等地质危害和煤层自燃、煤尘爆炸影响。研究结果为13煤的开采打下了坚实的基础。     

尧都区地下水水化学特征成因分析与探讨

根据尧都区地下水水质监测资料,概括了全区的水化学特征,进而对其成因进行分析与探讨.对地下水的超采及防止污染提出了建议.     

地下含水层水资源赋存条件及其水化学特征—以贵州省安龙县幅为例

以贵州省安龙县1∶50 000水文地质图幅为例,采用含水层探采井的水质、水量监测数据,分析不同含水层水资源赋存特征及其与水化学的相关性。研究结果表明:（1）研究区含水层可分为纯碳酸盐岩管道含水层、非纯碳酸盐岩裂隙含水层、碎屑岩裂隙含水层、松散岩类孔隙含水层4种类型,各含水层中地下水水化学类型均以HCO-Ca?Mg型为主;（2）除非纯碳酸盐岩含水层探采井的降深与水体中Mg2+、HCO-3浓度呈现出显著的负相关性（R2=-0.77/-0.74）外,其余离子浓度与钻井单位涌水量、降深的相关性均不显著,相关系数(R2)均小于0.3;（3）非纯碳酸盐岩含水层和松散岩类含水层的总矿化度（TDS）、总硬度（TH）含量均比纯碳酸盐岩含水层低5 mg?L-1以上,TDS、TH的高值区均集中于纯碳酸盐岩含水层中,而低值区则分布于松散岩类含水层。      

盈江县旧城地区离子吸附型稀土矿特征及控矿条件

云南盈江旧城地区地处滇西亚热带温热环境,出露了大面积的稀土元素背景值较高的古近纪二长花岗岩体,岩体经过长期的表生成矿作用,形成了多处风化壳离子吸附型稀土矿.通过实施的取样钻、槽探等工程控制,可以看出盈江地区的稀土矿体,主要赋存于古近纪花岗岩体风化壳底部之半风化层上部,矿化分布较广泛,其潜在资源远景规模达大型或超大型.     

长江中下游安徽段离子吸附型稀土矿成矿条件分析

本文通过对长江中下游地区安徽段广泛出露的花岗岩类风化壳离子吸附型稀土矿含矿性进行系统的取样分析,发现毛坦岩体、花园巩岩体、花山岩体、黄梅尖岩体风化壳存在稀土矿化,矿化体主要集中在岩体全风化层.结合前人在同位素年代学、矿物学、岩石地球化学等方面取得的研究成果以及离子吸附型稀土矿成矿理论,认为区内燕山晚期A型花岗岩风化壳发...     

罗甸南部多金属矿特征与成矿条件初步分析

罗甸南部位于右江造山带北缘,褶皱断层较为复杂,穹状构造发育,有利于多金属矿床形成。本文简要叙述该区多金属矿产特征,并对其成矿条件进行初步分析。     

陕西省佳县地质灾害发育特征与形成条件分析

佳县位于陕西省东北部黄河中游西岸,受特殊的地形地貌、岩土体结构、降雨和人类活动等影响,区内地质灾害发育数量多,危害大,各类地质灾害的形成条件、分布规律和发育特征具有诸多共性和一定规律,同时又呈现出各自差异性特征和独特规律。     

宁夏盐池县地质灾害特征及形成条件分析

宁夏盐池县是全区地质灾害地质灾害较为发育的地区之一。通过宁夏盐池县地质灾害详细调查工作,查明地质灾害点共计426处,其中滑坡295处、崩塌92处、泥石流19处、不稳定斜坡17处、地面塌陷3处,主要分布在南部地貌类型为黄土丘陵的麻黄山乡、大水坑镇东南部以及惠安堡镇南部,具有黄土地区地质灾害典型特征。地质灾害形成条件包括地形地貌、地层结构、降雨和人类工程活动。     

北京市密云县前火石岭泥石流沟形成条件及特征分析

北京地区现有泥石流沟856条,分布在北京北部燕山山脉和西部太行山脉一带,受地形地貌、地质条件、降雨条件以及人类活动影响较明显,总体以暴雨沟谷型泥石流为主。密云县前火石岭泥石流沟是燕山山脉一带典型的一条泥石流沟,文章在地质调查和勘查的基础上,从地质条件、地形地貌、降雨条件、人类活动等方面,综合分析前火石岭泥石流沟的形成条件及特征,同时对泥石流沟的发育情况进行深入剖析,按10年一遇暴雨强度的设计标准,在泥石流沟上游、中游、沟口3个断面计算泥石流运动特征参数,得出该泥石流沟为低易发-中等易发稀性水石流,目前处于发展阶段的停歇期,区域高强度集中降水为泥石流灾害的激发因素,泥石流的峰值流量等运动参数沿沟逐渐增大。分析结果对该泥石流沟的治理方案制定具有重要意义,对燕山山脉一带泥石流沟的防治具有借鉴作用。     

Investigation of hydrochemical characteristics of groundwater from the Cretaceous-Eocene limestone aquifer in southern Ghana and southern Togo using hierarchical cluster analysis

The most relevant controls on the water quality within the Cretaceous-Eocene limestone aquifer of the Keta Basin, Ghana, and the coastal sedimentary basin of Togo were assessed using Q-mode hierarchical cluster analysis (HCA) and mass-balance modelling. The pattern recognition technique of HCA was employed for partitioning hydrochemical data from a total of 65 surface and borehole samples from the study area into water groups. A spatial plot of the water groups consisting of samples from the limestone aquifer shows that the vast majority of samples belonging to the same group are located in close proximity to one another, suggesting the same processes and/or flow paths in the limestone aquifer system. Geochemical reaction models of selected water groups were constructed using PHREEQC-2. The hydrochemical compositions of the water groups and the mass-balance calculations indicate that the dominant processes and reactions responsible for the hydrochemical evolution in the system are: (1) carbonate equilibria, (2) silicate weathering reactions, (3) limited mixing with saline water, and (4) ion exchange. The combined use of HCA and mass-balance modelling has shown to be a useful approach in interpreting groundwater hydrochemistry in an area where large uncertainties exist in the understanding of the groundwater flow system.     

Major ion chemistry of groundwater in the extreme arid region northwest China

The Ejina Basin, located in arid northwest China, is one of the most arid areas in the world. In recent years, rapid development has created a greater demand for water which is increasingly fulfilled by groundwater abstraction. Detailed knowledge of geochemical evolution of groundwater and water quality can improve the understanding of a hydrochemical system, and promote sustainable development and effective management of groundwater resources. To this end, a hydrochemical survey was conducted in the Ejina Basin in order to identify the major hydrochemical characteristics. The results of chemical analysis indicate that groundwater in the area is brackish. The major ions, TDS, and hydrochemical types of different areas are highly variable and show an obvious zonation from the recharge area to the discharge area. Saturation index (SI), calculated according to the ionic ration plot, indicates that the gypsum-halite dissolution reactions take place under the condition of the rock weathering to some extent, and evaporation is the dominant factor to determine the major ionic composition in the study area.     

市政管道状况评价技术研究

本文首先对管道缺陷状况进行了总结分类,并对管道缺陷状况评价方法进行了探讨,以此为基础,用VB6．0开发了相应的管道状况评价软件,然后,采用层次分析法对管道各类缺陷严重性进行了分析,得出管道修复优先次序,为市政管道的评价与维护提供了一定的参考意见。     

离子交换反应合成铅长石的实验研究

对长石与Pb(NO_3)_2粉末在380℃条件下反应48h的产物进行XRD分析,显示出现了d值分别为6.54、3.42、3.32、3.27,2.57的铅长石的5个特征峰。XPS分析表明Pb4f7/2在长石矿物中的结合能为138.39~138.44eV。实验证明Pb2 与长石结构中的碱性或碱土性离子发生了离子交换反应,生成了铅长石。     

离子色谱法测定冰川末端大气PM2.5可溶性离子及其来源解析

为了研究祁连山西段冰川末端地区大气PM_2.5细粒子中可溶性无机离子组分的变化特征,于2011年采集了一批大气PM_2.5的Telfon滤膜样品,并应用离子色谱对可溶性离子进行了分析。样品采用超纯水超声萃取各种水溶性离子,优化的萃取溶液体积为25 mL,萃取时间为30 min,萃取液用0.45μm纤维滤膜过滤,各种离子在一定浓度范围内线性关系良好,相关系数r>0.999。所测样品的阴阳离子中,SO₄^2-、NO₃^-、Ca²⁺、和NH₄⁺的质量浓度约占到水溶性离子总量的88%。可溶性离子浓度呈现出春夏高、秋冬低的季节变化特征,夏季可溶性离子浓度最高。     

离子色谱梯度淋洗技术检测水中阴离子

通过实验确定了使用梯度淋洗技术检测矿泉水中阴离子的方法。检出限能够达到5.4～25.5ng/mL,精密度能够达到0.33%～1.10%。     

Identifying the characteristic signatures of fold-accommodation faults

Hand-specimen and outcrop scale examples of folds are analyzed here to identify the characteristic signatures of fold-accommodation faults. We describe and analyze the geometric and kinematic relationships between folds and their associated faults in detail including the structural position and spatial distribution of faults within a fold, the displacement distribution along the faults by applying separation–distance plots for the outcrop scale examples, and the change of cut-off angle when the fault cut across folded layers. A comparison between fold-accommodation faults and fault related folds based on their separation–distribution plots and the problem of time sequence between faulting and folding are discussed in order to distinguish fold-accommodation faults from the reverse faults geometrically and kinematically similar to them. The analysis results show that fold-accommodation faults originate and terminate within a fold and usually do not modify the geometry of the fold because of their limited displacement. The out-of-syncline thrust has a diagnostically negative slope (separation value decreasing away from the upper fault tip) in the separation–distance graph. The change of cut-off angle and the spatial distribution of faults display a close relationship with the axial surface of the fold. Our analyses show that fold-accommodation faults are kinematically consistent with the flexural slip of the fold. The interbedded strata with competence contrast facilitate formation of fold-accommodation faults. These characteristic signatures are concluded as a set of primary identification criteria for fold-accommodation faults.     

全球生态系统服务的状况与趋势

简要介绍了千年生态系统评估（MA）状况与趋势工作组的报告《生态系统与人类福祉：现状与趋势》中的第2部分，即“对生态系统服务的评估”。该部分主要对全球生态系统服务在20世纪末的总体状况，以及它们在20世纪后半叶的主要变化趋势进行了评估。评估结果表明，在MA明确评估的24项服务中，15项处于下降趋势，约占60%；4项处于上升趋势，约占18%；其余5项（约占22%）存在显著的空间或时间差异，即在有些地区（时段）处于上升趋势，而在另外一些地区（时段）处于下降趋势。这些变化主要表现在：①全球谷类作物和牲畜等方面的生态系统服务已经取得了显著的提高，但同时却对淡水资源和调控害虫等方面的服务造成了巨大的损害；② 按照当前的捕捞速度，野生鱼类资源已经无法承受人类的持续捕捞；③ 许多地区的淡水资源已经不能满足人类和生态系统的需求，如果延续当前的水资源利用模式，供需之间的差距将会继续扩大；④ 在对污染物质进行无害化处理、保持养分平衡、调控自然灾害，以及控制害虫、疾病与入侵生物的爆发等方面，许多生态系统的调节服务已经呈现出明显的下降趋势；⑤作为生态系统提供供给服务、调节服务和文化服务的基础条件，全球生态系统的支持服务出现了复杂的变化趋势。