东濮凹陷“高阻红”的地质时代与划分对比     

赵蔚  蒋飞虎  唐淑艳 《地层学杂志》2007,31(1):50-55

渤海沿岸盆地东濮凹陷内发育的“高阻红”地层的地质时代归属和划分对比问题长期以来一直存在争议。通过区域地层对比、黏土矿物同位素年龄测试、古生物分析和“高阻红”地层赋存状况等的分析,确认该区“高阻红”地质年代属早三叠世,它与华北地区中—西部广泛分布的下三叠统刘家沟组以及和尚沟组可以对比。  相似文献   

振动沉管灌注桩施工及事故处理     

李荣再 《云南地质》2007,26(2):264-269

简要介绍振动沉管灌注桩施工方法,以及质量事故控制和处理措施。  相似文献   

ROCESSES OF EPHEMERAL GULLY EROSION   总被引：2，自引：0，他引：2  

Javier Casali 《国际泥沙研究》2000,(1)

IINTRoDUCTIONEphemeralgulliesaresmallerosionalchannelsonagriculturalIandscapescausedbytheconcentrationofoverlandflowtypicallybetweentwoopposingslopes(ahollow),oftenformedduringasingIerainfaIlevent.Sincethescouredsoilvolumeisnotverylargewithinthesegullies,farmerscaneasilyrefillthem.Ingeneral,ephemeralgulliescanreappearatornearthesamelocationonayearlybasisbecausethesurfacetopograPhyofthefielddoesnotchangeappreciably.Mostephemeralgulliesoccuroncultivatedfieldswithhighlyerodiblesoils,withlit…  相似文献   

Relationship between bed shear stress and suspended sediment concentration:annular flume experiments     

Yunwei WANG  Qian YU  and Shu GAO  Dr.  Prof.  Ministry of Education 《国际泥沙研究》2011,(4):513-523

In this study,annular flume experiments were carried out,using the sediment samples collected from the lower part of the inter-tidal zone at Xiaoyangkou,Jiangsu coast,China.The Ariathurai-Partheniades equation was used to determine the bed shear stress,by evaluating variations in the suspended sediment concentration within the water column.The derived relation between the bed shear stress and suspended sediment concentration shows that,at various stages of seabed erosion, suspended sediment concentration increases rapidly when the flow velocity is increased,but the pattern of change in the bed shear stress does not follow suit.At low concentrations,bed shear stress initially increases markedly with increasing flow velocity.However,when the concentration reaches an apparently critical level around 0.55 kg m"3,the rate of change in the bed shear stress abruptly slows down,or becomes almost constant,in response to further increases in the flow velocity.Results of experiments indicate that,from a critical level onward,suspended sediment concentration has a strong influence on the bed shear stress.  相似文献   

老挝琅勃拉邦爬奔金矿矿床地质及成因探讨     

李会恺  张翔君  王军 《云南地质》2011,30(3):280-284

琅勃拉邦省位于“三江”成矿带南延部分,爬奔金矿为受剪切带控制的低温热液矿床,矿体产出空间符合里德尔剪切裂隙规律,进一步工作后该矿区应有中型以上规模。  相似文献   

云南麻栗坡芭蕉箐铅锌矿成因探讨     

刘晓佳 《云南地质》2011,30(3):305-307,288

矿体似层状、透镜状赋存于中寒武系田蓬组碳酸盐岩岩系中,北东向褶皱的滑脱空间、断裂破碎带为容矿的重要场所。  相似文献   

滇南南坡铜矿成矿条件及矿床成因     

吕晓宏  张搜  周仕雄  坚润堂 《云南地质》2011,30(4):411-414

南坡铜矿床是在原来沉积铜矿的基础上,经地下水作用次生富集而成的富矿体。  相似文献   

Sediment transport mechanisms and selective removal of soil particles under unsteady-state conditions in a sheet erosion system     

Elham Sirjani  Majid Mahmoodabadi  Artemi Cerda 《国际泥沙研究》2022,37(2):151-161

Selective removal of particles and nutrients by water erosion is a key factor in soil erosion studies.Most agricultural soils are located on gentle slopes where fertility is high;however,until now,the main attention on sediment transport mechanisms was paid to high-slope gradients,where soil erosion is intense,but soils are less productive.Despite the importance of sediment size distribution(SSD) and transport mechanisms under unsteady-state conditions,few studies have been done on this issue.Hi...  相似文献   

Effects of bed perturbation and velocity asymmetry on ripple initiation: wave-flume experiments     

Tomohiro Sekiguchi  Tsuguo Sunamura 《Coastal Engineering》2004,50(4):231

Laboratory experiments using a wave flume were designed to examine the threshold condition for ripple formation under asymmetrical oscillatory flows on an artificially roughened bed. Three types of sand beds were prepared in the experiments: they were flat, notched, and notch-mounded beds with bed roughness increasing in this order. The beds were constructed with three kinds of well-sorted sand with similar density, but different diameters. Data analyses were made using the two dimensionless parameters: the mobility number, M, a simplified form of the Shields number, and the Ursell number, U, a surrogate for asymmetry of flow field. The result confirmed that the threshold for ripple initiation is decreased with increasing bed perturbation and that as the bed perturbation increases, the dependency of this threshold on the flow asymmetry becomes less and finally null for the notch-mounded bed. This relationship is quantified by the following equations: M=17−14.5e^−0.03U on the flat bed, M=5.0−2.5e^−0.1U for the notched bed, and M=2.5 for the notch-mounded bed. A comparison between the previous field data and the present laboratory findings indicates that the threshold in the notch-mounded bed experiment, M=2.5, seems to provide a critical condition for rippling in the natural environment.  相似文献   

老寨湾金矿控矿层位时代及控矿因素新认识   总被引：2，自引：0，他引：2  

杨昌毕  舒培华 《云南地质》2012,(1):12-17

矿区主要金矿化层为下奥陶统老寨组(O1l),而非下泥盆统坡松冲组。金矿化主要受断裂构造+岩浆活动+不整合面+岩性等多因素的综合控制,矿体富集的空间部位与断裂构造及深部岩浆活动有密切的关系。丰富和扩展了滇东南地区加里东不整合面控矿理论的内涵,明确矿区深部及外围找矿空间。  相似文献