黄海中部海岸末次冰盛期第1硬质黏土层的粒度分维特征及其环境意义     

赵梅 《海洋地质前沿》2008,24(10):8-13

沉积物粒度分布特征是衡量沉积介质能量,判别沉积环境和水动力条件的最基本的方法之一,粒度分维是粒度的另外一个重要参数。在前人对硬黏土成因研究的基础上,选取目前具有影响力说法的典型的沉积物：湖泊相、潮滩相、风成沙、粉尘、洪泛平原、黄土等进行了分维值的计算,通过与小庙洪区钻孔的末次冰盛期第1硬质黏土的粒度分维的对比,初步探索其粒度特征。从粒度分布与分维的角度进一步印证了该区第1硬质黏土层的沉积环境为河湖相。  相似文献   

Analysis of stochastic characteristics of the Benue River flow process     

李致家 《中国海洋湖沼学报》2008,26(2):142-151

Stochastic characteristics of the Benue River streamflow process are examined under conditions of data austerity. The streamflow process is investigated for trend, non-stationarity and seasonality for a time period of 26 years. Results of trend analyses with Mann-Kendall test show that there is no trend in the annual mean discharges. Monthly flow series examined with seasonal Kendall test indicate the presence of positive change in the trend for some months, especially the months of August, January, and February. For the stationarity test, daily and monthly flow series appear to be stationary whereas at 1%, 5%, and 10% significant levels, the stationarity alternative hypothesis is rejected for the annual flow series. Though monthly flow appears to be stationary going by this test, because of high seasonality, it could be said to exhibit periodic stationarity based on the seasonality analysis. The following conclusions are drawn： （1） There is seasonality in both the mean and variance with unimodal distribution. （2） Days with high mean also have high variance. （3） Skewness coefficients for the months within the dry season period are greater than those of the wet season period, and seasonal autocorrelations for streamflow during dry season are generally larger than those of the wet season. Precisely, they are significantly different for most of the months. （4） The autocorrelation functions estimated ＂over time＂ are greater in the absolute value for data that have not been deseasonalised but were initially normalised by logarithmic transformation only, while autocorrelation functions for i = 1, 2 365 estimated ＂over realisations＂ have their coefficients significantly different from other coefficients.  相似文献   

确山县石滚河国土资源所“执法现场”变“普法课堂”     

陈永国 《河南国土资源》2008,(5):26

“乡亲们,今天县乡联合执法大队将依法拆除村民雷军义的违法建房,原因是雷军义违犯了（《土地管理法》第77条：农村村民未经批准或者采取欺骗手段非法占用土地建住房的……责令退还非法占用的土地,限期拆除在非法占用土地上新建的住房。由此给雷军义造成了1万多元经济损失,对此,我们表示遗憾。希望大家吸取教训,引以为戒,今后一定要依法使用宅基地,以免给自己造成不必要的损失。”  相似文献   

Spatial Variability of Mass Movements in the Satluj Valley,Himachal Pradesh during 1990～2006     

Vikram Gupta  M. P. Sah 《山地科学学报》2008,5(1):38-51

Satluj Valley is known to have a history of landslides and related mass movement activities since the geological times. Geological and geomorphological settings combined with anthropogenic activities constitute a propensity towards slope failure. During the last two decades,the area witnessed substantial increase in athropogenic pressure,mainly due to the exploitation of hydropower potential,changing landuse pattern and population growth. In addition,a shift of the climatic patterns in the form of larger area falling under the influence of rains was observed. These natural as well as anthropogenic changes in the area have resulted in increased spatial coverage of landslide in the area. This paper documents these changes during 1990～2006.  相似文献   

碎屑岩沉积构型研究若干进展          下载免费PDF全文

吴胜和  岳大力  冯文杰  张佳佳  徐振华 《古地理学报》2021,23(2):245-262

近10年来,国内外的沉积构型研究从之前的以精细表征为主扩展到成因机制分析.文中以同生逆断层控制的冲积扇、可容空间影响下的曲流河点坝、浅水缓坡背景下的三角洲指状砂坝以及大陆斜坡微盆地背景下的重力流沉积等为例介绍相关研究进展.(1)挤压盆地边缘复杂的同生逆断裂构造活动控制了冲积扇的构型要素类型、叠置样式、分布演化及定量规模...  相似文献   

渤海南部早-中更新统湖相沉积的粒度特征及其对沉积环境的指示          下载免费PDF全文

吕文哲  易亮  付腾飞  陈广泉  徐兴永  于洪军 《海岸工程》2017,36(1)

通过对莱州湾南岸Lz908孔下部47m沉积物的粒度分析,揭示了该地区沉积物的粒度特征:平均粒径介于3.2Φ~7.4Φ,大部分为黏土质粉砂,少部分为砂质粉砂,亦含有少量粉砂质砂;分选系数介于1.1~2.5,分选较差;偏度绝大多数介于0.7~2.4,表现为正偏和极正偏;峰度介于1.9~3.4,表现为平坦和正态。通过粒级组成、粒度象特征、粒度结构散点图等的综合分析,表明:钻孔下部沉积物与上部沉积物相比,指示了相对低能稳定的水动力环境;莱州湾南岸地区在早-中更新统处于浅湖相与深湖相交替存在的沉积环境。因此,本文认为对渤海莱州湾南岸地区沉积物粒度特征的研究可以有效的判断沉积环境,提取古环境信息,是沉积环境的重要替代指标。  相似文献   

青藏高原古里雅冰帽冰碛和冰水沉积物粒度特征及其意义   总被引：1，自引：1，他引：0  

张延广  方小敏  毛子强  申茂华  张涛  昝金波  杨胜利 《冰川冻土》2021,43(3):701-713

冰冻圈演化不仅与青藏高原水塔变化、地表侵蚀风化及荒漠化密切相关,还深刻影响着亚洲季风系统和全球气候,冰碛物的粒度组成可以为冰冻圈演化提供重要信息,但高原冰碛物的特征粒度组成及其形成机理仍不清楚,高原冰碛物与高原冷黄土及河湖沉积物的关系也不明确.为此,选择青藏高原最大的冰帽——古里雅冰帽的冰碛物及系列冰水沉积物,开展系统...  相似文献   

河流相沉积的河型转换特征与控制因素及其油气地质意义 ——以南苏丹Melut盆地Ruman地区坳陷期Jimidi组为例   总被引：1，自引：1，他引：0  

陈彬滔  于兴河  王磊  史忠生  马轮  薛罗  史江龙  白洁  赵艳军 《沉积学报》2021,39(2):424-433

河流相砂体是陆相含油气盆地的重要储层类型,其河型的时空转换不仅是研究盆地演化的直接证据,更是精准评价与预测油气储层的核心内容,已成为近年来国内外沉积研究的热点之一.以Melut盆地Ruman地区坳陷期Jimidi组为例,通过开展层序划分、岩相类型与岩相组合分析、高分辨率储层反演、以及砂体平面展布分析,结果表明:1)坳陷...  相似文献   

结构-功能耦合下的城市水系连通方案两阶段优化          下载免费PDF全文

窦明  宋孙娟  石亚欣  靳梦 《水科学进展》2022,33(1):79-90

传统水系连通方案编制主要以水系结构为主导,忽略了连通后对水系功能的影响,本文在进行城市水系布局时,将水系连通形状和连通功能两部分纳为一体来制定水系连通方案。基于中心性评价方法,提出河段重要性计算方法来定量刻画河段重要性;借助隶属度函数建立连通功能及其表征参数的函数关系,据此量化水系连通功能效果;以河网连通功能达标率和水系连通性满足度为优选目标,建立结构-功能耦合下的水系连通方案两阶段优化模型,优选最佳闸门联合调度方案。以清潩河许昌段为实例,优化原河网及不同水系连通情景的连通性。研究表明：经过优化后,原河网清潩河水系连通性总体较好,但护城河附近和饮马河的连通性较差;连通护城河和清泥河、连通饮马河和小洪河能极大地提升护城河附近和饮马河的水系连通性。  相似文献   

Hydrodynamic characteristics and sediment transport of a tidal river under influence of wading engineering groups     

陈珺  唐洪武  肖洋  嵇敏 《中国海洋工程》2013,27(6):829-842

By taking the Yong River for example in this paper, based on the multiple measured data during 1957 to 2009, the change process of runoff, tide feature, tidal wave, tidal influx and sediment transport are analyzed. Then a mathematical model is used to reveal the influence mechanism on hydrodynamic characteristics and sediment transport of the wading engineering groups such as a tide gate, a breakwater, reservoirs, bridges and wharves, which were built in different periods. The results showed the hydrodynamic characteristics and sediment transport of the Yong River changed obviously due to the wading engineering groups. The tide gate induced deformation of the tidal wave, obvious reduction of the tidal influx and weakness of the tidal dynamic, decrease of the sediment yield of flood and ebb tide and channel deposition. The breakwater blocked estuarine entrances, resulting in the change of the tidal current and the reduction of the tidal influx in the estuarine area. The large-scale reservoirs gradually made the decrease of the Yong River runoff. The bridge and wharf groups took up cross-section areas, the cumulative affection of which caused the increase of tidal level in the tidal river.  相似文献