河控浅水三角洲沉积构型          下载免费PDF全文

吴胜和  徐振华  刘钊 《古地理学报》2019,21(2):202-215

自浅水三角洲的概念提出以来,已经历了60多年的研究历史。虽然在诸多方面取得了较大的研究进展,但在浅水三角洲的概念内涵、砂体成因类型及沉积构型样式等方面仍存在一定的分歧。本文探讨了浅水三角洲概念的内涵,并总结和分析了其沉积构型特征和样式。根据浪基面和河-盆水深比(初始河道深度与河口盆地水体深度比值),可将三角洲分为极浅水三角洲、较浅水三角洲和较深水三角洲。典型的浅水三角洲为极浅水三角洲,发育于河-盆水深比值大于或等于1的浅水水体,分流河道可下切至下伏的前三角洲沉积。根据三角洲前缘分流河道与河口坝的组合样式,将河控浅水三角洲的端元类型分为分流砂坝型和指状砂坝型。分流砂坝型三角洲为河道入海(湖)后形成的多级分叉的河口坝与分流河道系统,平面上呈扇状,河—坝组合呈现“河在坝间”的样式,而指状砂坝型三角洲为指状砂坝与分流间湾相间分布的系统,平面上呈枝状,河—坝组合呈现“河在坝内”的样式。  相似文献   

鄂尔多斯盆地子洲地区上三叠统延长组长1段沉积相和浅水三角洲河口坝发育规律          下载免费PDF全文

李媛  张元福  王桐  张庆  王敏  李睿智  袁晓冬 《古地理学报》2019,21(5):757-766

鄂尔多斯盆地上三叠统延长组沉积时期为大型坳陷湖盆,具有坡缓、水浅和构造相对稳定的特点,有利于浅水三角洲的形成。通过野外露头观察发现,鄂尔多斯盆地子洲地区大理河剖面三叠系延长组长1段发育浅水三角洲沉积。其中,三角洲前缘沉积中发育河口坝,河口坝内部具明显3期下细上粗反韵律,而且每期河口坝内部具泥质夹层厚度具有向上增加的趋势,指示可容纳空间向上增大。总结了浅水三角洲河口坝发育规律,认为河口坝的形成由可容纳空间与沉积物供给共同决定:(1)在可容纳空间变大的情况下,河口坝的形成由沉积物供应量决定,若有一定量的沉积物供给,则形成具湖侵退积序列的河口坝沉积;(2)在可容纳空间变小的情况下,河口坝的形成由剩余可容空间决定,若有剩余可容纳空间,则形成具湖退进积序列的河口坝沉积;(3)当没有可容纳空间时,河口坝不发育。鄂尔多斯盆地子洲地区延长组长1段河口坝的形成属于可容纳空间变大且有沉积物供给的情况。  相似文献   

珠江口盆地番禺低隆珠江组—韩江组高精度层序地层   总被引：2，自引：1，他引：1       下载免费PDF全文

谢利华  林畅松董 伟秦成岗  张忠涛熊 亮 《中国地质》2009,36(2):366-377

以岩心、测井和三维地震等资料分析为基础,结合古生物分析,将珠江口盆地番禺低隆起新近系珠江组到韩江组划分为7个三级层序,归为明显削蚀不整合明显上超不整合、底超不整合弱削蚀或上超不整合和整合界面等.每个三级层序内以主要水进面为界划分出3～4个四级层序.结合地震属性分析,揭示了四级层序框架内沉积体系的分布和发育.受古地貌和相对海平面变化的控制,高位域三角洲砂体主要分布于隆起及以西地区,低位域三角洲前缘砂体主要分布于隆起-缓坡坡折带.概括出高精度层序地层格架内4种潜在的非构造圈闭发育模式并进行了分布预测,认为东部的低位域三角洲前缘砂体和东南部的断裂坡折带下的低位域三角洲前缘砂体,具有良好的成藏条件,易形成构造-岩性或岩性地层油气藏.  相似文献   

广利河口拦门沙运动特性及水力插板断面模型试验研究     

贾友海  拾兵  陈兆林 《海岸工程》2004,23(2):9-14

通过对广利河口拦门沙运动参数的测试及3种下水力插板上波浪力的试验研究,定量给出了泥沙初动、中动、普动、扬动变化曲线,准确绘制了水力插板波压力分布图,为广利河口拦门沙治理和航道管理提供了科学依据。  相似文献   

Rapid formation of hyperpycnal sediment gravity currents offshore of a semi-arid California river     

Jonathan A. Warrick  Jingping XuMarlene A. Noble  Homa J. Lee 《Continental Shelf Research》2008

Observations of sediment dispersal from the Santa Clara River of southern California during two moderately sized river discharge events suggest that river sediment rapidly formed a negatively buoyant (hyperpycnal) bottom plume along the seabed within hours of peak discharge. An array of acoustic and optical sensors were placed at three stations 1 km from the Santa Clara River mouth in 10-m water depth during January–February 2004. These combined observations suggest that fluid mud concentrations of suspended sediment (>10 g/l) and across-shore gravity currents (∼5 cm/s) were observed in the lower 20–40 cm of the water column 4–6 h after discharge events. Gravity currents were wave dominated, rather than auto-suspending, and appeared to consist of silt-to-clay sized sediment from the river. Sediment mass balances suggest that 25–50% of the discharged river sediment was transported by these hyperpycnal currents. Sediment settling purely by flocs (∼1 mm/s) cannot explain the formation of the observed hyperpycnal plumes, therefore we suggest that some enhanced sediment settling from mixing, convective instabilities, or diverging plumes occurred that would explain the formation of the gravity currents. These combined results provide field evidence that high suspended-sediment concentrations from rivers (>1 g/l) may rapidly form hyperpycnal sediment gravity currents immediately offshore of river mouths, and these pathways can explain a significant portion of the river-margin sediment budget. The fate of this sediment will be strongly influenced by bathymetry, whereas the fate of the remaining sediment will be much more influenced by ocean currents.  相似文献   

环珠江口与环东京湾地区产业发展及环境比较   总被引：1，自引：0，他引：1  

江璐明  张虹鸥  梁国昭 《热带地理》2005,25(4):331-335,345

对中国环珠江口地区和日本环东京湾地区在地理、产业发展及环境问题等各方面作比较研究,重点阐述了两个区域经济及产业发展过程中对其环境的影响,借鉴东京湾发展的经验教训,根据环珠江口地区产业发展的实际情况,在分析珠三角和泛珠三角产业发展在空间上的同心圆结构的基础上,指出了环珠江口区产业发展的趋势,提出该地区产业布局及生态环境保护的建议.  相似文献   

Numerical Simulation of Wave Field at the Kemena River Mouth in Kalimantan Island     

CHEN Yang SUN Jingshi Associate Professor  Tianjin Research Institute of Water Transport Engineering  Tianjin  P. R. China. Professor  Tianjin Research Institute of Water Transport Engineering  Tianjin  P. R. China. 《中国海洋工程》1999,(2)

-By use of the parabolic equation of numerical simulation of wave which is suitable forlarge-angle propagation and Crank-Nicolson differential method,the wave field at the Kemema Rivermouth has been studied for analysis of sediment movement in the area.In order to reflect wave energy lossaccurately,the Bretchneider-Reid formula is quoted and the friction coefficient in the formula is discussedin this paper.The calculation results indicate that the wave becomes a little damped at the mouth ofKemena River influenced by the topography and bottom friction,and the wave at the east beach is higherthan that at the west beach,because the east beach extends out.  相似文献   

密云水库东西库区的水质与浮游藻类分析   总被引：3，自引：1，他引：2  

李慧敏  孟凡艳  杜桂森  刘晓端  刘静  宋福 《湖泊科学》2007,19(2):146-150

湖泊生态工程因其净化效果好、投资小、运行简单等优点,近十多年来在我国受到了广泛关注,并得到了越来越多的应用.本文介绍了云南洱海污染治理的工程技术之一--桃溪河口净化工程的设计思路.该工程基于暴雨径流输送污染物的特征,将水力工程、土石工程与生物工程有效结合,通过在桃溪河口建立溢流堰,将桃溪正常来水导截入由桃溪河口9个废弃鱼塘改造而成的净化池进行净化.工程运行的水质监测表明,该工程已发挥一定的净化效果,对TN的去除率达55.2%-86.9%,其中对NO3-N和NH4 -N的去除率都较高,对P的去除率达76.4%-88.2%,对悬浮物的去除率达29.4%-49.5%.  相似文献   

水下井口探测技术研究          下载免费PDF全文

杨肖迪  姚志广  淳明浩  罗小桥 《海岸工程》2019,38(3):232-239

在海上油田开发过程中,往往存在一些当时不具备开发条件的水下井口。这些井口一方面现阶段具有重新开发价值,另一方面也是海洋工程建设的障碍物。而水下井口尺度小,常用的调查手段较难探测到。文中介绍了浅地层剖面仪和磁力仪的原理,并开展了浅地层剖面仪和磁力仪综合探测水下井口的应用与分析。结果表明浅地层剖面仪和磁力仪均可探测到井口,在浅地层剖面图像上表现为垂向的声学空白带,为桩坑和井口的反射;磁异常平面等值线为等轴状,存在极大值和极小值,井口位于极大值和极小值之间。浅地层剖面仪和磁力仪探测的井口位置相差1m,与给定井口坐标偏差2m,满足工程需求。因此使用浅地层剖面仪和磁力仪综合探测水下井口在现阶段不失为一种可行的方法。  相似文献   

Numerical study of three-dimensional wave-induced longshore current's effects on sediment spreading of the Huanghe River mouth     

LIANG Bingchen  ZHAO Hongping  LI Huajun  WU Guoxiang 《海洋学报(英文版)》2018,37(2):129-138

A three-dimensional wave radiation stress is introduced into the hydrodynamic sediment coupled model COHERENS-SED, which has been developed through introducing wave-enhanced bottom shear stress, wave dependent surface drag coefficient, wave-induced surface mixing, SWAN, damping function of sediment on turbulence, sediment model and depth-dependent wave radiation stress to COHERENS. The COHERENS-SED is adopted to study the effects induced by wave-induced three-dimensional longshore current on suspended sediment spreading of the Huanghe River (Yellow River) mouth. Several different cases divided by setting different wave parameters of inputting boundary waves are carried out. The modeling results agree with measurement data. In terms of simulation results, it is easy to know that three-dimensional wave radiation stress plays an obvious role when inputting boundary wave height is stronger than 3 m. Moreover, wave direction also affects the sediment spreading rules of the mouth strongly too.  相似文献