Cohesive Sediment Transport in the Jiaojiang River Estuary, China   总被引：1，自引：0，他引：1  

W.B. Guan  E. Wolanski  L.X. Dong 《Estuarine, Coastal and Shelf Science》1998,46(6):861-871

Extensive data were obtained of the water and fine sediment dynamics during spring tides in the extremely turbid Jiaojiang River estuary at spring tides. These data enabled the calibration of a two-dimensional (2-D) width-integrated model. Four processes dominated the mud dynamics. These were, firstly, the formation at slack tide of soft mud deposits with an erosion constant much smaller than that of the underlying compacted sediment, secondly the sediment-induced buoyancy effects, thirdly the collapse of the turbulence by the sediment suspension in the fluid mud range and fourthly the inflow of sediment at the mouth of the estuary. These findings demonstrate the necessity to have detailed field data to enable quantitative, as opposed to qualitative, modelling of mud dynamics in turbid estuaries. The estuary is infilling with sediment from the East China Sea and not from riverine inflow, this sediment presumably originates from the Yangtze River located 200 km further north.  相似文献   

锯缘青蟹秋苗土池越冬的试验研究   总被引：4，自引：0，他引：4  

王桂忠  林琼武 《台湾海峡》1998,17(4):468-472

本文报道１９９３和１９９４年秋季作者培育的部分锯缘青蟹仔蟹苗土池越冬试验。结果表明人工培育的青蟹苗在闽南地区的自然条件下,可以在室外土池完全越科,成活率可达６０－８０％,水温是影响青蟹生命活动的主要因素;由于越冬期间青蟹营养积累不足,导致难以顺利地完成越冬后的第一次生长蜕壳,造成大量死亡,这是影响青蟹越冬存活率的主要因素之一;越科后期病死青蟹肝胰组织进行涂片处理,发现６只受检蟹中２只肝胰组织中有日  相似文献   

PGS饱和盐水泥浆在钻井生产中的应用   总被引：1，自引：0，他引：1  

孙国强 《煤田地质与勘探》1992,20(1):68-72

预胶化淀粉(PGS)具有强降失水性能。用PGS配制的饱和盐水泥浆性能稳定,在钻井过程中形成的泥皮薄而致密。这种泥浆能抑制粘土水化膨胀,防止井壁坍塌,而且抗Ca2+、Mg2+污染的效果好。在生产试验中发现,PGS饱和盐水泥浆尤其适用于钻进高盐高钙地层,如岩盐层、石膏层、芒硝层。维护这种泥浆的关键是维持盐饱和、控制无用固相含量、净化泥浆、保持pH值在9~11。PGS饱和盐水泥浆配方简单,成本低廉,使用方便,在生产中具有广泛的推广应用价值。   相似文献   

LBM生产工艺和造浆性能的关系     

崔迎春 《煤田地质与勘探》1997,25(6):58-60

在总结以往研究成果基础上,进一步研究了LBM湿挤压钠化改性和增效机理。通过试验揭示了LBM系列产品生产工艺和产品造浆性能之间的关系。   相似文献   

基于多波束测深的海底沉管基槽回淤监测与分析     

高耿明  潘润秋 《测绘信息与工程》2010,35(4):32-33

应用了多波束技术,分析了海洋环境和气候条件下的回淤情况,实现了港珠澳大桥海底隧道基槽开挖回淤分析原位测试、施工后数据的收集和处理。  相似文献   

High-resolution X-ray fluorescence profiling of hybrid event beds: Implications for sediment gravity flow behaviour and deposit structure     

Arif Hussain  Peter D. W. Haughton  Patrick M. Shannon  Jonathan N. Turner  Colm S. Pierce  Arnau Obradors-Latre  Simon P. Barker  Ole J. Martinsen 《Sedimentology》2020,67(6):2850-2882

Hybrid event beds form when turbidity currents that transport or locally acquire significant quantities of mud decelerate. The mud dampens turbulence driving flow transformations, allowing both mud and sand to settle into dense, near-bed fluid layers and debris flows. Quantifying details of the mud distribution vertically in what are often complex tiered deposits is critical to reconstructing flow processes and explaining the diverse bed types left by mud-bearing gravity flows. High-resolution X-ray fluorescence core scanning provides continuous vertical compositional profiles that can help to constrain mud distribution at sub-millimetre scale, offering a significant improvement over discrete sampling. The approach is applied here to cores acquired from the Pennsylvanian Ross Sandstone Formation, western Ireland, where a range of hybrid event beds have been identified. Raw X-ray fluorescence counts are calibrated against element concentrations and mineral abundances determined on coincident core plugs, with element and element log-ratios used as proxies to track vertical changes in abundances of quartz, illite (including mica), chlorite and calcite cement. New insights include ‘stepped’ (to higher values) as opposed to ‘saw-tooth’ vertical changes in mud content and the presence of compositional banding that would otherwise be overlooked. Hybrid event beds in basin floor sheets that arrived ahead of the prograding fan system have significantly cleaner sandy components than those in mid-fan lobes. The latter may imply that the heads of the currents emerging from mid-fan channels entrained significant mud immediately before they collapsed. Many of the H3 debrites are bipartite with a sandier H3a division attributed to re-entrainment and mixing of a trailing debris or fluid mud flow (H3b) with sand left by the forward part of the flow. Hybrid event bed structure may thus partly reflect substrate interaction and mixing during deposition, and the texture of the bed divisions may not simply mirror those in the suspensions from which they formed.  相似文献   

The micromorphology of paraglacial and periglacial slope deposits: a case study from Morfa Bychan,West Wales,UK     

Charles Harris 《第四纪科学杂志》1998,13(1):73-84

Micromorphological analysis of the crudely stratified diamictons exposed in coastal sections at Morfa Bychan, west Wales, is presented and discussed. Three major units, Yellow Head, Blue Head and Brown Head, have been recognised, and their crudely stratified nature, plus clast orientations, indicate that they were all subject to mass movement down the flanks of the adjacent coastal hills. Earlier workers have suggested a periglacial environment for this mass movement, but recently it has been proposed that the Blue Head, at least, may have accumulated in a paraglacial environment through gravitational redistribution of recently deposited unstable till. It is shown here that the Yellow Head contains occasional dense silt-rich coatings on the upper surfaces of sand and gravel grains, although other cryogenic micromorphological phenomena were not observed. The Blue Head, however, contains no clear cryogenic micromorphological features, although there is abundant evidence for sediment shearing and grain rotation within the matrix. The Brown Head contains diffuse grain coatings and lenticular aggregates very similar to those observed elsewhere in periglacial solifluction deposits. Thus it is concluded that accumulation of the Blue Head was rapid, and took place in a paraglacial environment as a result of mudflow. The Yellow Head may represent periglacial solifluction immediately prior to glaciation, whereas the Brown Head accumulated above the Blue Head as a result of periglacial weathering of the adjacent exposed hill tops, and subsequent downslope solifluction of the weathering product. © 1998 John Wiley & Sons, Ltd.  相似文献   

西北太平洋采薇海山表层沉积的岩石磁学特征及其对深海环境过程的指示          下载免费PDF全文

林震  易亮  王海峰  邓希光  杨继超  付腾飞  于洪军  谢强  邓成龙 《地球物理学报》2019,62(8):3067-3077

采薇海山位于西北太平洋麦哲伦海山区,是由中国发现、命名并负责资源勘探的重点调查区之一.本文利用大洋27航次在采薇海山北坡MABC-05站获得的箱式沉积物样品,开展了详细的岩石磁学研究.结果显示表层沉积物中的磁性矿物以颗粒较细的、矫顽力较低的磁铁矿为主;利用对数正态分布函数可以区分三个具有不同矫顽力值的磁性颗粒组分,并发现磁性颗粒的矫顽力值变化可以有效指示沉积物埋藏后的早期成岩特征.在参考现代物理海洋过程的基础上,我们推测南极底层水团的演化和太阳辐射的变化可能共同影响了采薇海山区海洋底层环境过程.这一结果为探讨南极气候状况对北太平洋的可能影响,评估海洋上层与底层的相互作用等重要科学问题提供了新途径.  相似文献   

南海东北部陆坡与恒春海脊天然气水合物分布的地震反射特征对比   总被引：3，自引：0，他引：3  

尚继宏  李家彪 《海洋学研究》2006,24(4):12-20

对“探宝号”调查船2001年8月在南海东北部陆坡及台湾南部恒春海脊海域采集的多道地震剖面资料进行了地震反射波数据分析、解释和研究,并对南海北部陆坡、陆隆及其东侧俯冲带等区域天然气水合物矿藏的成藏规律及分布特征作了初步的分析与探讨,结果表明:(1)南海东北部陆坡和台湾南部恒春海脊海域地震剖面上均显示有BSR,但两区域构造成因、形式和相关地质环境的不同造成了天然气水合物的成因及过程不同。(2)南海东北部陆坡区域的天然气水合物形成与该区广泛发育的断裂带、滑塌构造体及其所形成的压力场屏蔽环境有关,而台湾南部恒春海脊海域天然气水合物的形成则与马尼拉海沟俯冲带相关的逆冲推覆构造、增生楔及其所对应的海底流体疏导体系有关。(3)南海陆缘区域广泛发育有各种断裂带、滑塌构造体、泥底辟、俯冲带、增生楔等,且温压环境合适,是天然气水合物矿藏极有可能广泛分布的区域。  相似文献   

泥火山与天然气水合物   总被引：1，自引：0，他引：1  

梁杰  龚建明  陈建文 《海洋地质前沿》2006,22(12):20-23

系统地介绍了泥火山在全球的分布特征;阐述了水下泥火山形成的原因和机制;总结出4类泥火山的形成原因和两个泥火山形成机制;在此基础上深入地分析了天然气水合物与泥火山的关系及泥火山中天然气水合物的资源量。  相似文献