山西地质趣谈(十四)(连载)

正三、从地理名称查地质变迁1.万泉无泉运城地区的万荣县,是万泉与荣河两个县合并命名的。而"万泉无泉"的民谚,则是指万泉县没有泉水。既然如此,为何有万泉的地名?难道这仅仅是人们的一种祈盼吗(例如中阳县有一个穷山村叫"万年饱",就是人们饿怕了,希望以后能永世不挨饿而命名)?查县志发现,万泉原来是因"城临山涧,地多涌泉"而得名的。古万泉城建于峨嵋台地主峰——孤峰(海拔1411米)的北麓,几乎是千里旱原之顶端。其北东、北西有两条黄土冲沟切过,如今都是滴水俱无的干沟。那么当时"地多涌泉"     

Experiments on Channel Evolution due to Dam Removal in Taiwan

Due to safety concerns and habitat restoration for landlocked salmon,a 13-m high check dam on Chijiawan Creek was removed in late May 2011 in Taiwan.We conducted experiments to understand channel evolution of different scenarios.We further compared our experimental results of riverbed elevation changes with the analytical solutions derived from the diffusion equation and field dynamics as well after the creek experienced the first flood event.The results indicated that magnitude of discharges and notch size are dominant factors in resulting channel evolution.While the largest differences between grain size distribution are associated with discharge,the largest differences in net change in upstream volume are associated with notch size.While the theoretical equation could help understand the channel change after dam removal,it only explained the evolution closer to the dam.The physical experiments,on the other hand,provided insights especially with regard to comparing alternative proposed management actions.The discrepancies between predicted and actual outcome highlight more needed inputs for future dam-removal assessments.     

中国水荒“危言耸听”?

正自进入7月份以来,高温天气致使我国西南、西北多省市出现持续干旱天气。甘肃、云南、重庆等干旱严重的省市河流断流,严重影响了农业生产和人们生活,再度引起了人们对我国水危机的关注。水资源供需矛盾日益加剧我国是一个干旱缺水严重的国家。我国淡水资源总量为28000亿立方米,占全球水资源的6%,仅次于巴西、俄罗斯和加拿大,居世界第四位,但人均只有2300立方米,仅为世界平均     

Multiple temporal scale relationships of bankfull discharge with streamflow and sediment transport in the Yellow River in China

This paper presents a study on the characteristics of multiple time scales of bankfull discharge and its delayed response to changes of flow conditions using continuous wavelet analysis for data from selected hydrological stations in the Yellow River basin. Results showed that bankfull discharge series had one or two dominant time scales. For example, the Huayuankou station in the lower reach of the Yellow River had two dominant time scales of 19-20 years and 545 years. The dominant time scales of the bankfull discharge series were generally consistent with the dominant time scales of water discharge and sediment concentration series, indicating that the channel morphology inherits the characteristics of the hydrological system in terms of multiple time scales. In addition, the wavelet coefficients of the bankfull discharge series had a phase difference in relation to those of the sediment concentration series, with a delay time that varied from 3 to 16 years at different sites. This delay time or relaxation time is a result of the delayed response of bankfull discharge to flow conditions, which was significant for channel adjustments in response to changes of flow conditions. The findings of the multiple time scales and the delayed response are of importance for further study of channel morphology of fluvial systems.     

黄河内蒙段河道冲淤量与水沙输移过程的关系分析

根据1952～2003年黄河内蒙古河段实测断面资料分析,天然状态下该河段均处在淤积状态,青铜峡、三盛公水库建成运行初期水库蓄混排清,不同的水沙组合使河道有冲有淤,青铜峡水库蓄满失去蓄混排清功能后,河道又长期处在淤积状态。河道冲淤量与来水量、来沙量的线性组合高度相关,表明该河段冲淤量与河道的水沙组合有直接的因果关系,由此建立了计算河道冲淤量的数学模型。来沙系数是判断河道冲淤变化的关键指标,实测资料分析表明:来沙系数小于或等于0.005时河道发生冲刷,来沙系数在0.005～0.009之间时河道有冲有淤,来沙系数大于0.009时河道发生淤积,来沙系数大于0.015时淤积量趋于稳定,且以1.0为渐近线。     

分布式水文模型中河流水深及其与地下水相互作用的耦合模拟

大尺度流域水文模型一般只模拟河道径流,对河流水深和流速并不关注。在进行河流-地下水相互作用模拟时,河流水深（水位）是一个重要因素,其时空变化及其对河流-地下水水量交换的影响应加以考虑。本文就流域分布式水文模型中河流水深的时空变化计算及其与地下水的实时耦合模拟进行了研究,提出了相应的计算方法,改进了大尺度水文模型WATLAC,并通过V-型流域考题进行了检验。模拟结果显示,模型有效地模拟了V-型流域的河流水深、地下水水位沿河道的时空变化以及河流与地下水的水交换量,揭示了河流-地下水相互作用关系在降雨过程中的变化规律及主控因子。此外就河床糙率对河流水深及河流与地下水间水交换量的影响做了模拟分析,发现河床糙率的改变将影响河流水深,从而进一步影响河流与地下水的水交换量。本文提出的算法较为真实地模拟了河流洪水演进过程及其对河流-地下水相互作用的影响,模型适用于河流-地下水相互作用明显的区域,可作为评估地表-地下水相互影响的有效计算工具。     

基于尖点突变的河型稳定性判定方法

冲积河道的自我调整过程是多因素相互作用的复杂响应过程,对冲积河道河型的稳定性和调整方向进行判定是河流动力学的基本问题之一。根据突变理论中的尖点突变模式,采用影响河道稳定性的控制变量与状态参量,建立河道平衡状态方程,并推导得到河流状态判别式。通过对100多条天然河流及实验河段进行验证,结果显示这一方法能判定冲积河流的河型稳定状态,并对其调整方向作出预测,为实际工程中的河流整治提供一定的参考。     

地震分频解释技术在河道砂预测中的应用

地震资料分频处理技术是一种比常规地震属性识别储层更有效的方法。该方法将一定时窗内地震反射波通过离散傅里叶变从时间域换转换到频率域,用转换后的振幅谱和相位谱识别薄储层的厚度变化和边界。通过该技术可以对地震资料中所有单频信号进行有针对性的分析,已经证明是一种具有较高可信度的技术。针对胜利油田老河口油田老168井区馆陶组河道砂油藏厚度薄、横向变化大的地质特征,本文运用分频处理技术对该井区馆陶组地层砂体分布进行预测,并对储层非均质性进行了分析,经钻井证实,预测结果与实际情况十分吻合。     

松辽盆地钱家店砂岩型铀矿成矿地质特征

通过对钱家店铀矿床产出的地质背景、地质构造环境、矿床铀矿物特征、蚀变地球化学特征、微量元素地球化学特征、成矿物质来源及成矿年代学等综合研究,认为钱家店铀矿床受"晚白垩世姚家期辫状河道洼地、晚白垩世嫩江期末反转隆升剥蚀构造天窗、NNE向贯通性基底断裂"三位一体控制,矿床成因类型为同生沉积后生叠加复成因型。这为进一步的找矿工作提供了依据。     

Metaliogenic characteristics of Qianjiadian sandstone uranium deposit in Songliao basin

通过对钱家店铀矿床产出的地质背景、地质构造环境、矿床铀矿物特征、蚀变地球化学特征、微量元素地球化学特征、成矿物质来源及成矿年代学等综合研究,认为钱家店铀矿床受“晚白垩世姚家期辫状河道洼地、晚白垩世嫩江期末反转隆升剥蚀构造天窗、NNE向贯通性基底断裂”三位一体控制,矿床成因类型为同生沉积后生叠加复成因型.这为进一步的找矿工作提供了依据.