Hydrodynamic and isotopic investigations for evaluating the mechanisms and amount of groundwater seepage through a rockslide dam     

Marco Petitta  Gabriele Scarascia Mugnozza  Maurizio Barbieri  Gianluca Bianchi Fasani  Carlo Esposito 《水文研究》2010,24(24):3510-3520

This study addresses the influence of landslide dams on surface water drainage and groundwater flow. In the study area of Scanno Lake and Sagittario River (Central Italy), a limestone rockslide‐avalanche formed a lake, which has an outlet that is occasionally active, showing infiltration into the rockslide dam. Several springs are present at the lake's base and are partly fed by seepage through the rockslide debris. Piezometric surveys, discharge measurements, pumping tests and chemical analyses are tools used to build a conceptual model of the groundwater flow and to evaluate the flow through the rockslide debris. Seasonal water isotopic signatures validate the assumed model, showing a mixing of infiltration recharge and groundwater seepage throughout the rockslide debris. Various recharge areas have been found for springs, pointing out those directly fed by the rockslide debris aquifer. Hypotheses about seasonal groundwater mixing between the regional carbonate aquifer and the rockslide debris aquifer are supported by isotope results. Seasonal changes in groundwater table level due to recharge and surface losses from seasonal outlet have been correlated with isotopic groundwater composition from the rockslide debris aquifer and the downstream springs; this relationship highlights the role of the rockslide dam body on the hydrodynamics of the studied area. Relationships between surface waters and groundwater in the area have been completely understood on the basis of water isotopic fingerprinting, finally obtaining a complete evaluation of groundwater renewable resources and its regimen. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Late Quaternary fluvial aggradation and incision in the monsoon‐dominated Alaknanda valley,Central Himalaya,Uttrakhand, India     

Navin juyal  Yaspal Sundriyal  Naresh rana  Shipra chaudhary  Ashok k. Singhvi 《第四纪科学杂志》2010,25(8):1293-1304

The present study aims to explain the spatial and temporal variability in phases of aggradation/incision in response to changes in climate and seismicity during the late Quaternary in the Alaknanda River valley (a major tributary of the river Ganges or Ganga). Geomorphology, stratigraphy and optical dating of the fluvial sediment reveal that the oldest fluvial landforms preserved in the south of the Main Central Thrust are debris flow terraces developed during the early part of pluvial Marine Isotopic Stage 3. Following this, a period of accelerated incision/erosion owing to an increase in uplift rate and more intense rainfall occurred. In the Lesser Himalaya, three phases of valley fill aggradation around 26 ± 3 ka, 18 ± 2 ka and 15 ± 1 ka and 8 ± 1 ka occurred in response to changes in monsoon intensity and sediment flux. The last phase was regionally extensive and corresponds to a strengthening of the early Holocene Indian Summer Monsoon. A gradual decline in the monsoon strength after 8 ± 1 ka resulted in reduced fluvial discharge and lower sediment transport capacity of the Alaknanda River, leading to valley fill incision and the development of terraces. The study suggests that fluvial dynamics in the Alaknanda valley were modulated by monsoon variability and the role of tectonics was subordinate, limited to providing accommodation space and post‐deposition modification of the fluvial landforms. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

反循环中心取样雾化钻探应用于砾岩型金矿取样地质效果及其编录方法     

刘宝成  袁力 《吉林地质》1994,13(2):75-81

中心取样钻探是一种全新的钻探方法，具有效率快、取样准确、岩样采取率高的特点。可用于砾岩型金矿勘探评价，获取的矿层深度、品位、厚度、岩心采取率等均能满足地质要求，利用回返物质能够进行正常地质编录。  相似文献   

古代锡矿今何在：关于我国古代文明史上一大疑案的探讨     

唐桂秋 《湖南地质》1991,10(3):263-266

中原地区是我国古代青铜冶炼中心,却未见一处锡矿产地,当时炼锡原料从何而来,迄今仍为一大疑案。多数学者偏向源于华南,现知这里锡资源丰富,自然易圆其说,但也有认为就地取材于中原的,只是现今没有见到它的产地。笔者从锡矿的找矿前提分析,亦认为不能排除中原地区古时开采过,今后还找得到锡矿的可能性。  相似文献   

重庆市冬季雾的物理化学特性   总被引：32，自引：8，他引：32  

李子华  彭中贵 《气象学报》1994,52(4):477-483

在１９８９年１２月１５日至１９９０年１月１５日和１９９０年１２月７日至１９９１年１月７日，对重庆市区冬季雾进行了综合观测试验。从多项观测资料综合分析了雾的物理化学结构，揭示了重庆市区冬季雾许多重要的有别于外地的特征。  相似文献   

西藏中部的发震构造   总被引：3，自引：0，他引：3  

吴章明  曹忠权 《中国地震》1994,10(1):19-27

西藏中部的发震构造是晚第四纪以来强烈活动的北东、北西和近南北向的活动断层及受其控制的地堑半地堑型盆地和拉分盆地，东西向缝合线和断层晚第四纪以来的运动性不明显，对地震活动没有明显的控制作用，活动断层的规模和晚第四纪以来的运动性质对地震的震级和数量有明显的的控制作用。８级地震的发生与拉分盆地内部张剪切断层与盆地一侧新活动幅度大的次级走滑断层的相互作用密切相关。  相似文献   

鄂西—渝东地区热史恢复及烃源岩成烃史   总被引：16，自引：4，他引：16  

卢庆治  马永生  郭彤楼  胡圣标 《地质科学》2007,42(1):189-198

根据鄂西—渝东地区镜质体反射率数据进行的热史恢复结果表明:该区在晚二叠世初期达到最高古热流(可达68~78mW/m²,地表热流),从晚二叠世初到现今古热流持续降低,在侏罗纪末期古热流平均为~54mW/m²(地表热流);鄂西—渝东地区中生界与新生界之间不整合面的剥蚀量可达1700~4000m。成烃史研究表明:鄂西—渝东地区志留系烃源岩在晚志留世—早二叠世进入生油高峰,在早-中三叠世进入生气期,中侏罗世晚期进入过成熟干气阶段,快速生烃时期是在晚志留世、二叠纪—中三叠世及早-中侏罗世;而二叠系烃源岩在早三叠世进入生油门限,于中-晚三叠世达到生油高峰,在中-晚侏罗世进入生气期,晚侏罗世晚期进入过成熟,快速生烃时期是在早-中三叠世及侏罗纪。  相似文献   

重庆城口地区早前寒武系黑色岩系研究:(1)铂族元素成矿潜力评估   总被引：2，自引：0，他引：2  

罗泰义  宁兴贤  罗远良  陶琰  朱丹  姚林波  马德云 《矿物学报》2007,27(3):287-301

重庆城口地区从震旦统到下寒武统发育有丰富的黑色岩系,20世纪末期在该地区黑色岩系中开展了大量的铂族元素(PGE)的找矿工作,但是由于种种原因,关于该地区是否存在PGE矿化异常,还没有得到最终的结论.本次研究在PGE分析方法论证的基础上,进行了大量样品的PGE分析和微量元素分析.主要结论如下①区域上上震旦统槽区和断块区两套黑色岩系在原始的沉积环境和物源供给上有较大的差异,虽然槽区上震旦统的黑色岩系具有和下寒武统黑色岩系相似但强度较低的V-Cu-Y-Mo-U异常,但基本上不具有明显的PGE-Au-Ag异常.②断块区水井沱组黑色岩系和平剖面西段新发现的U-V-Mo-PGE异常可能是今后工作的重点,Pt＋Pd最高达248.9×10-9,局部U-V都达到了工业品位.③槽区巴山组硅质岩四个剖面都揭示了在硅质岩中广泛存在连续的PGE异常,87个碳质硅质岩平均含Pt＋Pd 57.2×10-9,有10个样品Pt Pd》100×10-9,最高达196.5×10-9;大部分碳质硅质岩都具有不同程度的V-Cu-Y-Mo-Tl-U组合异常,V都达到了独立矿床的品位要求,其中猪草河、燕子河等剖面还存在厚度较大的富矿地段,特别是燕子河剖面,局部还存在REE＋Y的高异常,值得深入研究.④城巴地区下寒武统黑色岩系存在广泛的PGE异常,但没有达到PGE的矿化要求,建议加强该地区的钒矿和铀矿勘探研究,PGE可以综合评价.  相似文献   

滇中红层工程地质特性研究     

刘成 《云南地质》2007,26(4):428-438

介绍滇中红层形成的地质历史背景,红层分布范围,主要地层岩性及区内地质构造。重点讨论滇中红层特别是红层软岩的岩体原生结构,及后期受构造改造的岩体结构特性,岩体风化特性,岩体水理作用特性,岩体物理力学性质等四方面的工程地质特性。  相似文献   

Slip rates variability and sediment mobilization on a shallow landslide in the northern Swiss Alps     

Marco Schwab  Christine Läderach  Dirk Rieke-Zapp  Fritz Schlunegger 《Swiss Journal of Geoscience》2007,100(2):281-292

  相似文献