Hydrochemical variation in the springs water between Jerusalem–Ramallah Mountains and Jericho Fault,Palestine

The spatial and temporal changes of the composition of the groundwater from the springs along the Wadi Qilt stream running from the Jerusalem–Ramallah Mountains towards the Jericho Plain is studied during the hydrological year 2006/2007. The residence time and the intensity of recharge play an important role in controlling the chemical composition of spring water which mainly depends on distance from the main recharge area. A very important factor is the oxidation of organics derived from sewage and garbage resulting in variable dissolved CO₂ and associated HCO₃ ⁻ concentration. High CO₂ yields lower pH values and thus under-saturation with respect to calcite and dolomite. Low CO₂ concentrations result in over-saturation. Only at the beginning and at the end of the rainy season calcite saturation is achieved. The degradation of dissolved organic matter is a major source for increasing water hardness. Besides dissolution of carbonates dissolved species such as nitrate, chloride, and sulfate are leached from soil and aquifer rocks together with only small amounts of Mg. Mg not only originates from carbonates but also from Mg–Cl waters are leached from aquifer rocks. Leaching of Mg–Cl brines is particularly high at the beginning of the winter season and lowest at its end. Two zones of recharge are distinguishable. Zone 1 represented by Ein Fara and Ein Qilt is fed directly through the infiltration of meteoric water and surface runoff from the mountains along the eastern mountain slopes with little groundwater residence time and high flow rate. The second zone is near the western border of Jericho at the foothills, which is mainly fed by the under-groundwater flow from the eastern slopes with low surface infiltration rate. This zone shows higher groundwater residence time and slower flow rate than zone 1. Groundwater residence time and the flow rate within the aquifer systems are controlled by the geological structure of the aquifer, the amount of active recharge to the aquifer, and the recharge mechanism. The results of this study may be useful in increasing the efficiency of freshwater exploitation in the region. Some precautions, however, should be taken in future plans of artificial recharge of the aquifers or surface-water harvesting in the Wadi. Because of evaporation and associated groundwater deterioration, the runoff water should be artificially infiltrated in zones of Wadis with high storage capacity of aquifers. Natural infiltration along the Wadis lead to evaporation losses and less quality of groundwater.     

循化-化隆盆地晚白垩世以来盆山耦合过程: 来自物源与磷灰石裂变径迹年代学分析的证据

循化-化隆盆地新生代沉积及盆地基底和周缘山系磷灰石裂变径迹年代学分析揭示了青藏高原东北缘晚白垩世以来经历过3期隆升剥露事件: (1)盆地基底及拉脊山和西秦岭北缘构造带磷灰石裂变径迹年龄分析普遍记录了晚白垩世-始新世中期相对快速的区域性的隆升剥露事件, 西秦岭北缘快速抬升的起始时间为84Ma, 受控于向北的逆冲抬升; 向北到循化-化隆盆地中部的拉目峡抬升的起始时间为69Ma; 更北的拉脊山一带快速抬升期主要为40~50Ma, 从而反映晚白垩世-始新世中期的快速抬升由南向北逐渐扩展.这一期构造隆升事件导致循化-化隆盆地和临夏盆地缺失了北部西宁-民和盆地古近纪所具有的西宁群沉积.隆升剥露结束于31Ma左右, 此时化隆-循化盆地向东与同时期的临夏盆地相连为一个统一的大型西秦岭山前盆地, 两者具有相同的构造、沉积演化史, 因此循化-化隆盆地他拉组底部地层年龄最老不会超过临夏盆地最老地层的古地磁年龄, 即29Ma.(2)渐新世晚期约26Ma拉脊山开始双向逆冲隆升, 并可能延续到中新世早期约21Ma, 隆升作用使循化-化隆盆地成为挟持于拉脊山逆冲带和西秦岭构造带之间的山前挤压型前陆盆地, 循化-化隆盆地开始大规模沉积巨厚的他拉组冲积扇相粗碎屑岩.(3)通过循化-化隆盆地咸水河组和临夏组的沉积相分析、古流方向和砾石成分分析, 揭示出拉脊山构造带在中新世8Ma左右发生的最大规模的双向逆冲隆升事件, 这次事件直接导致循化-化隆盆地由前陆挤压盆地转变为山间盆地, 形成现今青藏高原东北缘的盆山地貌基本格局.      

济南市燕翅山铁矿采空区稳定性分析评价

济南燕翅山铁矿已闭坑多年,遗留大量的采空区潜在地面塌陷、山体崩塌及裂缝隐患,对当地人民群众生命财产安全构成威胁。该文对采空区稳定性进行了分析计算,并根据研究区实际,提出了主要地质灾害治理方法和措施建议。     

Environmental change,hydromorphological reference conditions and the restoration of Polish Carpathian rivers

In the twentieth century Polish Carpathian rivers were considerably modified by channelization and gravel mining, with significant detrimental effects to their ecological integrity, vertical stability of the streambeds and flood hazard to downstream river reaches. Restoration of the rivers is thus necessary to improve their ecological status and re‐establish geomorphic dynamic equilibrium conditions. Various approaches to defining hydromorphological reference conditions, proposed to date in river restoration literature, have serious deficiencies. In particular, environmental changes that took place in the catchments of Carpathian rivers during the twentieth century invalidate the historical state of the rivers as reference for their restoration. This is illustrated by a change from bar‐braided to island‐braided channel pattern that occurred in the past century in unmanaged sections of the Czarny Dunajec in response to a reduction in flow and sediment dynamics of the river. We indicate that reference conditions should be defined as those which exist or would exist under present environmental conditions in the catchment but without human influence on the channel, riparian zone and floodplain of the river which is to be restored. This assumption was tested through the evaluation of hydromorphological river quality of the Czarny Dunajec according to the European Standard EN‐14614. The evaluation confirmed a high‐status hydromorphological quality in an unmanaged channel section, which can thus be used as a reference for restoration of impacted river sections. Copyright © 2012 John Wiley & Sons, Ltd.     

新疆天山北坡经济带土地利用时空变化特征研究

基于GIS平台,以新疆各县市统计资料及Landsat TM 影像解译得到的三期土地利用数据为基础,对天山北坡经济带1996-2004年土地利用数量、类型及其变化进行了分析.结果得出,前后2个4年间,天山北坡经济带林地和未利用土地是先增加后减少.在8年尺度上土地利用总的动态特征是,耕地、园地、林地、水域、建设用地及未利用土地面积增加,草地面积减少.8年尺度天山北坡经济带综合土地利用动态度为12.95%.前4年综合土地利用动态度为12.83%,园地、水域及未利用土地的年变化率较大,林地的年变化率较小.后4年天山北坡经济带综合土地利用动态度为1.58%,建设用地与园地的年变化率较大,草地及耕地的变化率较小,前4年变化程度比后4年明显.最后,引入单一土地利用类型相对变化率反映出天山北坡经济带土地利用变化存在明显的区域差异.政策变动、经济发展、城市化水平、市场需求和人口增长是天山北坡经济带土地利用变化的主要原因.     

A call for Australian loess: discussion and commentary

A study of loess in Australia brings the idea of 'desert' loess back into view. Production of particles in deserts still presents problems, but deserts do make adequate storage regions for loess particles – usually produced in adjacent mountains. Straightforward for Central Asia or China (a particle source in High Asia and convenient deserts en route to eventual deposition), but the Sahara and Australian deserts traditionally present problems. If loess material is allowed to be silt-sized clay agglomerate particles as well as the usual clastic primary minerals, then loess in Australia seems reasonable. Loess acquires its remarkable loessic qualities via aeolian deposition – the nature of the particles is perhaps of lesser importance. A more generalised approach to airborne sediments might be attempted, with two major types of suspension material recognised: large dust (maybe coarse and very coarse silt, say 20–60 µm, or perhaps 4–6 phi) and small dust (fine and very fine silt, 2–8 µm, 7–9 phi). Loess is made from large dust.     

浅谈低山丘陵地区1/5万地质灾害调查工作——以江西省定南县为例

近年来,全国各省市陆续在开展1/5万地质灾害调查工作,不同地貌区地质灾害发育情况不同,调查方法与要求亦有区别。平原岗丘地区往往存在地质灾害点达不到观测点数量要求,需要增加地质环境点来满足精度;而西南高山区灾害点少但规模大,许多灾害点往往要通过大比例尺的测绘才能调查清楚。相比之下,低山丘陵地区地质灾害点具有点多面广的特点,规模多为小型,调查任务艰巨。本文以江西省定南县为例,阐述低山丘陵地区1/5万县(市)地质灾害调查的技术方法与认识,以期对类似地区的调查有所帮助。     

让江源之说回归真实

介绍了20世纪70年代江源地区的测图情况,指出沱沱河正源纳钦曲是兰州军区测绘部队1974年发现并测图。论述了认定河源诸项标准的由来,指出确定河源不可随意择取认定标准和确定主次。对"三源说"提出了质疑:沱沱河源于尕恰迪如岗雪山群东南侧两初始冰川,而非姜古迪如南侧冰川;认为把楚玛尔河定为长江的北源,既不符合实际,又搞乱了水系的干支名系关系,并出现多个源头,有违发源地的地域慨念。依江源数十条源流形成的密集扇形分布水系,提出长江发源地应表述为:源于唐古拉山脉北麓。按照认定河源的诸项标准,对长江诸源进行了分析与比量,当曲各项均为最优,认为当曲才是长江正源,源于霞舍日啊巴山峰东侧的多朝能谷地。指出量算长江的精确长度,应顾及诸多因素并建议重新量算。     

山地环境系统研究新框架

20世纪80年代,地球系统科学概念开始出现,同时期全球变化研究迅速展开,可持续发展理念提出并获得广泛认同,这些都为山地环境系统研究提供了新的发展契机.当前,全球山地环境系统研究面临两大问题:山地环境变化和山区发展挑战.国际上围绕山地环境系统研究,逐渐形成若干清晰的主题,包括山地构造地貌和山地气候地貌,山地灾害在山地环境演化过程中的作用,山地(及流域)环境系统生物地球化学循环,山地全球变化和人类活动的影响与适应等.对于我国山地研究来说,核心科学问题是:我国山地环境系统是如何响应不同时间尺度全球变化和日益加剧的人类活动的影响?在此背景下如何构筑我国山区可持续发展的根本战略和支撑战略?对此核心问题的全面深入研究,将有望使我国山地环境研究水平提高到一个新的更高层次,并占据国际山地研究领域中不可替代的重要位置.为此,我们提出,以我国山地环境大断面研究为抓手,以梯度格局、系统关联和区域差异等为研究切入点,在山地环境系统的格局、干扰、过程、响应和适应研究等方面有所突破,促成我国山地环境系统研究新框架的形成,为世界山地研究做出我们应有的贡献.     

Exploring large wood retention and deposition in contrasting river morphologies linking numerical modelling and field observations

Large wood tends to be deposited in specific geomorphic units within rivers. Nevertheless, predicting the spatial distribution of wood deposits once wood enters a river is still difficult because of the inherent complexity of its dynamics. In addition, the lack of long‐term observations or monitored sites has usually resulted in a rather incomplete understanding of the main factors controlling wood deposition under natural conditions. In this study, the deposition of large wood was investigated in the Czarny Dunajec River, Polish Carpathians, by linking numerical modelling and field observations so as to identify the main factors influencing wood retention in rivers. Results show that wood retention capacity is higher in unmanaged multi‐thread channels than in channelized, single‐thread reaches. We also identify preferential sites for wood deposition based on the probability of deposition under different flood scenarios, and observe different deposition patterns depending on the geomorphic configuration of the study reach. In addition, results indicate that wood is not always deposited in the geomorphic units with the highest roughness, except for low‐magnitude floods. We conclude that wood deposition is controlled by flood magnitude and the elevation of flooded surfaces in relation to the low‐flow water surface. In that sense, the elevation at which wood is deposited in rivers will differ between floods of different magnitude. Therefore, together with the morphology, flood magnitude represents the most significant control on wood deposition in mountain rivers wider than the height of riparian trees. Copyright © 2015 John Wiley & Sons, Ltd.