郑州市矿井水资源利用模式研究     

阎官法  郭雷 《地域研究与开发》2015,(3):148-150,161

为了进一步促进矿井水的开发利用,提高矿井水利用率,以郑州市为例,通过问卷调查、现场调研、专家座谈等方法调查研究了郑州市矿井水的分布及利用总体情况,从区域、矿区、矿井涌水量及利用量、用水特点等角度总结分析了郑州市矿井水开发利用的矿区高效自用、作为城市集中供水水源以及与工业用水大户连供3种模式,并结合实际提出了相关的对策和建议。  相似文献   

Sediment‐rich meltwater plumes and ice‐proximal fans at the margins of modern and ancient tidewater glaciers: Observations and modelling          下载免费PDF全文

Julian A. Dowdeswell  Kelly A. Hogan  Neil S. Arnold  Ruth I. Mugford  Martin Wells  J. Philip P. Hirst  Carole Decalf 《Sedimentology》2015,62(6):1665-1692

Turbid meltwater plumes and ice‐proximal fans occur where subglacial streams reach the grounded marine margins of modern and ancient tidewater glaciers. However, the spacing and temporal stability of these subglacial channels is poorly understood. This has significant implications for understanding the geometry and distribution of Quaternary and ancient ice‐proximal fans that can form important aquifers and hydrocarbon reservoirs. Remote‐sensing and numerical‐modelling techniques are applied to the 200 km long marine margin of a Svalbard ice cap, Austfonna, to quantify turbid meltwater‐plume distribution and predict its temporal stability. Results are combined with observations from geophysical data close to the modern ice front to refine existing depositional models for ice‐proximal fans. Plumes are spaced ca 3 km apart and their distribution along the ice front is stable over decades. Numerical modelling also predicts the drainage pattern and meltwater discharge beneath the ice cap; modelled water‐routing patterns are in reasonable agreement with satellite‐mapped plume locations. However, glacial retreat of several kilometres over the past 40 years has limited build‐up of significant ice‐proximal fans. A single fan and moraine ridge is noted from marine‐geophysical surveys. Closer to the ice front there are smaller recessional moraines and polygonal sediment lobes but no identifiable fans. Schematic models of ice‐proximal deposits represent varying glacier‐terminus stability: (i) stable terminus where meltwater sedimentation produces an ice‐proximal fan; (ii) quasi‐stable terminus, where glacier readvance pushes or thrusts up ice‐proximal deposits into a morainal bank; and (iii) retreating terminus, with short still‐stands, allowing only small sediment lobes to build up at melt‐stream portals. These modern investigations are complemented with outcrop and subsurface observations and numerical modelling of an ancient, Ordovician glacial system. Thick turbidite successions and large fans in the Late Ordovician suggest either high‐magnitude events or sustained high discharge, consistent with a relatively mild palaeo‐glacial setting for the former North African ice sheet.  相似文献   

西乌珠穆沁旗巴彦呼舒花岗闪长岩锆石U-Pb LA-ICP-MS年龄、地球化学、Hf同位素特征及其地质意义   总被引：1，自引：0，他引：1  

熊光强  刘敏  赵洪涛  张达  王浩然  王忠  胡兆初 《地质论评》2015,61(3):651-663

本文报道的花岗闪长岩位于内蒙古巴彦呼舒以东10 km处。大地构造位于中亚造山带中段的锡林浩特晚古生代褶皱带。LA-ICP-MS锆石U-Pb测年获得该岩体的侵位年龄为236.1±3.4Ma。花岗闪长岩Si O2为66.93%~67.22%,Al2O3为15.13%~15.53%,K2O为2.47%~2.56%,Na2O为4.35%~4.46%,A/CNK值为0.94~0.95,显示该地区花岗闪长岩属于偏铝质钙碱性岩;亏损高场强元素,Sr达416.6×10-6~425.7×10-6,Sr/Y值为42~49,显示出高Sr低Y的典型特征,具有Adakite(高锶低钇中酸性岩)或者高Sr花岗岩的特点。花岗闪长岩的锆石εHf(t)值介于13.3~15.7之间;两阶段模式年龄分别为249~356Ma和258~422Ma。综合分析表明,花岗闪长岩为西伯利亚板块和华北板块碰撞闭合后,加厚的下地壳部分熔融作用的产物。  相似文献   

塔里木盆地及邻区寒武纪——三叠纪构造古地理格局的初步重建     

李江海  周肖贝  李维波  王洪浩  刘仲兰  张华添  塔斯肯 《地质论评》2015,61(6):1225-1234

塔里木陆块寒武纪——三叠纪主要经历了从东冈瓦纳大陆西北缘裂解、到向劳亚大陆聚合的演化过程,北部长期为被动大陆边缘环境,南部主要为裂谷、持续裂解以及漂移过程中陆块地体增生拼合,主要为弧后前陆盆地或隆起。塔里木盆地一级层序地层、区域不整合事件、次级构造单元的构造演化等,与板块边界上构造活动及其板块运动轨迹的变化具有明显的一致性,板块边界上的挤压造山活动,造成盆地隆升以及盆地岩相古地理格局的剧烈变化。引发塔里木盆地早二叠世大火成岩省的地幔柱活动,垂向上也造成石炭系穹隆状剥蚀抬升。塔里木叠合盆地的形成是小陆块上不同时期不同盆地类型复合的产物,而在世界其他大板块上,它们在横向上可能处于不同位置,不会发生垂向叠合,而以不同时代的不同盆地出现。塔里木陆块较全球典型克拉通盆地规模小,在与周边陆块碰撞汇聚时受改造强烈,构造变形程度大并由陆块边缘向陆块内扩展,南、北两侧陆块边界上的强烈构造作用易于对整个盆地产生强烈影响,发育挤压期盆地隆起和前陆盆地等。  相似文献   

板块构造单元划分方法探讨——以青藏高原为例     

高延林 《青海国土经略》1993,(1)

作者认为板块构造单元划分应遵循4个基本原则,即系统原则、时空原则、层次原则,综合原则。在此基础上,提出岩石圈板块、地壳板段、构造沉积环境、板片构造(薄皮构造)四级划分方案。青藏高原岩石圈厚度120—170km,地壳厚度大密度低,上地幔厚度小密度大,莫霍面呈一“盆地”状。上地壳厚15—30km;壳内低速层厚5—10km,呈南浅北深产出;下地壳平均厚25km,藏北、青南有明显分层,藏南与固体上地幔成突变,缺少壳幔层。壳幔混合层,埋深50—65km,厚度13—21km。固体上地幔,平均厚度50—70km。本文将青藏高原划分为5个板块(一级单元),7个板段(二级单元),30个构造沉积环境(三级单元),着重对主要板块构造单元包容的主要板段特征进行了分析与研究,对秦祁昆板块构造域的范围与演化特征给予了分析。  相似文献   

Late Quaternary drainage reorganization assisted by surface faulting: The example of the Katrol Hill Fault zone,Kachchh, western India     

Deepak M. Maurya  Prabhuti Tiwari  Mohamedharoon Shaikh  Atul K. Patidar  Naimisha Vanik  Akash Padmalal  Laxman S. Chamyal 《地球表面变化过程与地形》2021,46(7):1268-1293

Drainage reorganization on restricted temporal and spatial scales is poorly-documented. We attempt to decode the relatively complicated mechanism of drainage realignment involving two small rivers that show structurally controlled, highly anomalous channel networks. We provide geomorphic and shallow subsurface evidence using ground-penetrating radar (GPR) for the presence of a buried paleo-valley flowing northward through the wind gap and surface faulting along the range bounding Katrol Hill Fault (KHF) which correlates with the previously known three surface faulting events in last ~30 ka bp . Most of the present river channels and the KHF zone are occupied by aeolian miliolite (local name) which is stratigraphic and lithologic equivalent of the Late Quaternary carbonate rich aeolianite deposits occurring in several parts of the globe. The history of drainage evolution in the study area comprises pre-miliolite, syn-miliolite and post-miliolite phases. Geomorphic evidences show that the paleo-Gangeshwar River flowed north through the wind gap and paleo-valley, while the short paleo-Gunawari occupied the saddle zone to the east of Ler dome prior to and during the phase of miliolite deposition which ended by ~40 ka bp . Southward tilting of the Katrol Hill Range (KHR) due to surface faulting cut off the catchment of the paleo-Gangeshwar River. The abandoned catchment stream extended its channel eastward along the strike through top-down process while the paleo-Gunawari River extended its course westward by headward erosion (bottom-up process). As the channels advanced towards each other they joined to produce the “S”-shaped bend which formed the capture point. We conclude that multiple surface faulting events along the KHF in the last ~30 ka bp , resulted in uplift and tilting of the KHR which caused drainage realignment by river diversion, beheading and river capture. Our study shows that the complexity of drainage reorganization processes is more explicit on shorter rather than longer timescales.  相似文献   

Tile drainage causes flashy streamflow response in Ohio watersheds     

Samuel A. Miller  Steve W. Lyon 《水文研究》2021,35(8):e14326

Artificial subsurface (tile) drainage is used to increase trafficability and crop yield in much of the Midwest due to soils with naturally poor drainage. Tile drainage has been researched extensively at the field scale, but knowledge gaps remain on how tile drainage influences the streamflow response at the watershed scale. The purpose of this study is to analyse the effect of tile drainage on the streamflow response for 59 Ohio watersheds with varying percentages of tile drainage and explore patterns between the Western Lake Erie Bloom Severity Index to streamflow response in heavily tile-drained watersheds. Daily streamflow was downloaded from 2010 to 2019 and used to calculated mean annual peak daily runoff, mean annual runoff ratio, the percent of observations in which daily runoff exceeded mean annual runoff (T_Qmean), baseflow versus stormflow percentages, and the streamflow recession constant. Heavily-drained watersheds (>40% of watershed area) consistently reported flashier streamflow behaviour compared to watersheds with low percentages of tile drainage (<15% of watershed area) as indicated by significantly lower baseflow percentages, T_Qmean, and streamflow recession constants. The mean baseflow percent for watersheds with high percentages of tile drainage was 20.9% compared to 40.3% for watersheds with low percentages of tile drainage. These results are in contrast to similar research regionally indicating greater baseflow proportions and less flashy hydrographs (higher T_Qmean) for heavily-drained watersheds. Stormflow runoff metrics in heavily-drained watersheds were significantly positively correlated to western Lake Erie algal bloom severity. Given the recent trend in more frequent large rain events and warmer temperatures in the Midwest, increased harmful algal bloom severity will continue to be an ecological and economic problem for the region if management efforts are not addressed at the source. Management practices that reduce the streamflow response time to storm events, such as buffer strips, wetland restoration, or drainage water management, are likely to improve the aquatic health conditions of downstream communities by limiting the transport of nutrients following storm events.  相似文献   

The effects of ditch dams on water-level dynamics in tropical peatlands     

Santosa Sandy Putra  Joseph Holden  Andy J. Baird 《水文研究》2021,35(5):e14174

A significant proportion of tropical peatlands has been drained for agricultural purposes, resulting in severe degradation. Hydrological restoration, which usually involves blocking ditches, is therefore a priority. Nevertheless, the influence of ditch blocking on tropical peatland hydrological functioning is still poorly understood. We studied water-level dynamics using a combination of automated and manual dipwells, and also meteorological data during dry and wet seasons over 6 months at three locations in Sebangau National Park, Kalimantan, Indonesia. The locations were a forested peatland (Forested), a drained peatland with ditch dams (Blocked), and a drained peatland without ditch dams (Drained). In the dry season, water tables at all sites were deeper than the Indonesian regulatory requirement of 40 cm from the peat surface. In the dry season, the ditches were dry and water did not flow to them. The dry season water-table drawdown rates — solely due to evapotranspiration — were 9.3 mm day⁻¹ at Forested, 9.6 mm day⁻¹ at Blocked, but 12.7 mm day⁻¹ at Drained. In the wet season, the proportion of time during which water tables in the wells were deeper than the 40 cm limit ranged between 16% and 87% at Forested, 0% at Blocked, and between 0% and 38% at Drained. In the wet season, water flowed from the peatland to ditches at Blocked and Drained. The interquartile range of hydraulic gradients between the lowest ditch outlet and the farthest well from ditches at Blocked was 3.7 × 10⁻⁴ to 7.8 × 10⁻⁴ m m⁻¹, but 1.9 × 10⁻³ to 2.6 × 10⁻³ m m⁻¹ at Drained. Given the results from Forested, a water-table depth limit policy based on field data may be required, to reflect natural seasonal dynamics in tropical peatlands. Revised spatial designs of dams or bunds are also required, to ensure effective water-table management as part of tropical peatland restoration.  相似文献   

平均热点参考基准的建立和岩石圈西向漂移的研究          下载免费PDF全文

朱新慧  孙付平  王刃 《地球物理学报》2013,56(8):2603-2612

对于大地测量应用来说,目前IERS机构在定义地球参考系时推荐采用岩石圈无整体旋转(No-Net-Rotation-NNR)约束条件,然而对于地球物理应用来说,相对于NNR参考基准的绝对板块运动数据可能会对地幔对流等研究结果产生误导.考虑到热点的运动,提出建立平均热点(MHS-Medial HotSpot)参考基准的方法,给出建立该基准的约束准则,分别以地学模型NNR-NUVEL1A和实测模型ITRF2005VEL为基础,建立了平均热点参考基准MHS-NUVEL1A和MHS-ITRF2005,并与其它基于热点的绝对板块运动模型进行了比较和分析;讨论了岩石圈的西向漂移,给出了岩石圈相对于下地幔整体旋转的更精确的定量估计,即基于实测的热点参考架MHS-ITRF2005和地学模型NNR-NUVEL1A之间的整体旋转为0.26°/Ma,旋转极在(50°S, 62°E),这与由板块的受力模型给出的岩石圈的整体旋转的旋转极很接近,旋转速率大致快了10%.  相似文献   

Flow network derivation from a high resolution DEM in a low relief,agrarian landscape   总被引：1，自引：0，他引：1  

Wolfgang Schwanghart  Geoff Groom  Nikolaus J. Kuhn  Goswin Heckrath 《地球表面变化过程与地形》2013,38(13):1576-1586

Digital flow networks derived from digital elevation models (DEMs) sensitively react to errors due to measurement, data processing and data representation. Since high‐resolution DEMs are increasingly used in geomorphological and hydrological research, automated and semi‐automated procedures to reduce the impact of such errors on flow networks are required. One such technique is stream‐carving, a hydrological conditioning technique to ensure drainage connectivity in DEMs towards the DEM edges. Here we test and modify a state‐of‐the‐art carving algorithm for flow network derivation in a low‐relief, agricultural landscape characterized by a large number of spurious, topographic depressions. Our results show that the investigated algorithm reconstructs a benchmark network insufficiently in terms of carving energy, distance and a topological network measure. The modification to the algorithm that performed best, combines the least‐cost auxiliary topography (LCAT) carving with a constrained breaching algorithm that explicitly takes automatically identified channel locations into account. We applied our methods to a low relief landscape, but the results can be transferred to flow network derivation of DEMs in moderate to mountainous relief in situations where the valley bottom is broad and flat and precise derivations of the flow networks are needed. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献