大别山榴辉岩氢氧同位素组成及其地球动力学意义

碧溪岭榴辉岩石至少经历了５个阶段的变质作用，矿物对氧同位素地质测温结果与通过岩石学方法计算的温度吻合得非常好，表明碧溪岭榴辉岩体中大部分同位素体系接近或达到平衡，且退变质作用未明显破坏这种平衡，榴辉岩全岩δ＾１８Ｏ为３‰～５‰指示其母岩玄武岩曾与地表水在变质作用之前发生过一定程度的交换作用。     

辽西区巫闾山的隆升历史

本文利用裂变径迹年代学方法 ,结合其他同位素年代学资料 ,通过构造热演化的定量分析 ,认为医巫闾山山脉的隆升历史经历了 118～ 81Ma期间的第 1个快速隆升阶段、81～ 14Ma期间的缓慢隆升阶段和 14Ma以来的第 2个快速隆升阶段。医巫闾山的隆升历史与两侧盆地的沉降历史有着很好的对应关系。山脉隆升相对盆地沉降有一个滞后期 ,山脉的快速隆升阶段对应盆地快速沉降的后期和消亡阶段。现今的医巫闾山山脉是 14Ma以来第 2个快速隆升阶段的产物 ,其隆起时间距今大约有 4～ 5Ma。     

阿尔泰大型剪切弧形推覆构造系及其应变恢复

海西中晚期阿尔泰造山带中发育了一系列剪切弧形推覆构造系,平面上呈弧形,剖面上呈叠瓦状背驮式由北东向南西斜—逆冲,其成因是斜向的壳内叠积及受早期类拗拉谷楔形构造和斜—逆冲下盘边界的联合影响,喜马拉雅期推覆系重新复活。应变恢复表明现长为50Km的剖面其原长最小为266.7Km,最小缩短量为216.7Km,海西早期类拗拉谷的最小宽度为170Km,应变恢复结果与斜—逆冲模式一致。     

Gravel‐bed river evolution in earthquake‐prone regions subject to cycled hydrographs and repeated sediment pulses

Sediment often enters rivers in the form of sediment pulses associated with landslides and debris flows. This is particularly so in gravel‐bed rivers in earthquake‐prone mountain regions, such as Southwest China. Under such circumstances, sediment pulses can rapidly change river topography and leave the river in repeated states of gradual recovery. In this paper, we implement a one‐dimensional morphodynamic model of river response to pulsed sediment supply. The model is validated using data from flume experiments, so demonstrating that it can successfully reproduce the overall morphodynamics of experimental pulses. The model is then used to explore the evolution of a gravel‐bed river subject to cycled hydrographs and repeated sediment pulses. These pulses are fed into the channel in a fixed region centered at a point halfway down the calculational domain. The pulsed sediment supply is in addition to a constant sediment supply at the upstream end. Results indicate that the river can reach a mobile‐bed equilibrium in which two regions exist within which bed elevation and surface grain size distribution vary periodically in time. One of these is at the upstream end, where a periodic discharge hydrograph and constant sediment supply are imposed, and the other is in a region about halfway down the channel where periodic sediment pulses are introduced. Outside these two regions, bed elevation and surface grain size distribution reach a mobile‐bed equilibrium that is invariant in time. The zone of fluctuation‐free mobile‐bed equilibrium upstream of the pulse region is not affected by repeated sediment pulses under the scenarios tested, but downstream of the pulse region, the channel reaches different fluctuation‐free mobile‐bed equilibriums under different sediment pulse scenarios. The vertical bed structure predicted by the simulations indicates that the cyclic variation associated with the hydrograph and sediment pulses can affect the substrate stratigraphy to some depth. Copyright © 2017 John Wiley & Sons, Ltd.     

Modelling climate change impacts on hydropower lake inflows and braided rivers in a mountain basin

This study models climate change impacts on the natural flow regime of braided rivers and inflows to hydropower lakes in a New Zealand mountain basin. Flow metrics include the magnitude, frequency, timing and duration of unaltered flows. The TopNet hydrological model was used to simulate impacts in the Upper Waitaki Basin of the South Island for the 1990s, 2040s and 2090s. An average emissions scenario and results from 12 global circulation models were used as input. Indicators of hydrological alteration and Kruskal-Wallis tests were used to evaluate flow differences. Modelled total inflows increase over time for all lakes, with most increases in winter/early spring and small decreases in summer/autumn. High flows generally increase, while low flows decrease. Although these changes may benefit hydropower and floodplain ecology, they may increase flood risk in winter and spring and drought risk in summer and autumn, causing additional challenges managing hydropower operations.

EDITOR M.C. Acreman

ASSOCIATE EDITOR S. Kanae     

桂西南喀斯特-北部湾海岸带生态环境脆弱性时空分异与驱动机制研究

为揭示生态环境脆弱性的时空分异和驱动因子,本研究在山江海视角下,以桂西南喀斯特-北部湾海岸带为典型研究区,运用空间主成分分析法,地理探测器模型,结合生态环境脆弱性综合指数,系统分析桂西南喀斯特-北部湾海岸带生态环境脆弱性的时空分异特征及驱动机制.结果 表明:①研究区2008、2013、2018年脆弱性指数分别为0.54...     

天人合一:山水诗歌的最佳心灵境界--魏晋诗歌山水意象论

在魏晋诗人笔下,山川河流已不纯粹是大自然的产物,而是成为了包含着诗人复杂情感的有生命、有性格的载体,其表现了诗人对茫茫宇宙的无穷探索及对个人短暂生命价值的无限追求,山的崇高伟大与水的深邃绵邈融汇成了作者的主体人格意识,这种物对人的异化具有异常丰富的内涵,是天人合一传统思想在诗歌领域的革新,无论自觉与否,作者都在力图达到这种物我两融的境界.     

太行山南段甘陶河群铜矿化特征及控矿因素分析

对太行山南段铜矿化带成矿地质背景、甘陶河群火山岩铜矿化特征及控矿因素进行了翔实的研究。结果认为,宏观上,太行山南段铜矿化带受裂陷槽和变质核杂岩构造体系的控制。铜矿化的产出受层位、岩性、韧脆性断裂、围岩蚀变等因素的联合控制,矿体呈脉状、似层状产出,矿石类型以细脉浸染状为主。进一步找矿方向重点应是深部找矿,工作方法采用综合找矿,主要手段为物探电法和钻探工程。     

祁连山夏季地形云结构和云微物理过程的模拟研究(II):云微物理过程和地形影响

本文是祁连山夏季地形云结构和微物理过程模拟的第II部分。文中利用第I部分中祁连山夏季两个地形云降水个例的模拟结果,详细分析了地形云及其降水发展期间云微物理过程的特征及变化,并通过与平坦地面条件下模拟结果的对比,研究了云发展过程中的地形影响。研究表明,地形云中微物理过程的发展受地形影响很大,冰相微物理过程明显增强;地形影响下云的主要降水机制也受到影响甚至被改变。     

兖州煤田采煤沉陷土地利用分区研究

从采煤沉陷土地持续利用角度,依据沉陷土地利用的自然和社会特性,提出采煤沉陷土地的分区方案;以兖州煤田为例,进行实用分区,并依据各分区的特点提出持续利用方向和方案;最后,根据分区实例,就采煤沉陷土地的持续利用提出几点建议。