泌阳凹陷毕店地区核三段湖底扇与重力流沉积

毕店地区处于泌阳凹陷中部,属于深水沉积区,含砂率多数在20%.该区核桃园组三段Ⅲ～Ⅵ砂组可识别出湖泊相和湖底扇相,具有较为典型的重力流沉积特征.在取心井段中可寻找到液化流、滑塌、拉裂与掉落岩块的滑动证据;此外,发育砂纹层理、泄水沟构造及渫状构造,后二者见于鲍玛序列C段,它们和砂纹层理伴生,这些岩块的上下层均为鲍玛BE段组合的浊积岩所构成的平整岩层.层拉平的地震剖面也表明核三段Ⅳ砂组中的平行、亚平行地震相之间夹有透镜状或波状、眼球状反射结构,平行、亚平行反射解释为深水背景泥沉积,而波状与眼球状反射为典型的湖底扇.     

Numerical Solution of Lock-Release Gravity Current with Viscous Self-Similar Regime

Lock-release gravity currents with a viscous self-similar regime are simulated by use of the renormalization group(RNG) k - ε model for Reynolds-stress closure. Besides the turbulent regime with initially a slumping phase of a conslant current front speed and later an inviseid self-similar phase of front speed decreasing as t^-1/3(where t is the time measured from release), the viseous self-similar regime is satisfactorily reproduced with front speed decreasing as t^-4/5,consistent with well known experimental observations.     

Geophysical Evidence of a Relict Oceanic Crust in the Southwestern Scotia Sea

The southwestern part of the Scotia Sea, at the corner of the Shackleton Fracture Zone with the South Scotia Ridge has been investigated, combining marine magnetic profiles, multichannel seismic reflection data, and satellite-derived gravity anomaly data. From the integrated analysis of data, we identified the presence of the oldest part of the crust in this sector, which tentative age is older than anomaly C10 (28.7 Ma). The area is surrounded by structural features clearly imaged by seismic data, which correspond to gravity lows in the satellite-derived map, and presents a rhomboid-shaped geometry. Along its southern boundary, structural features related to convergence and possible incipient subduction beneath the continental South Scotia Ridge have been evidenced from the seismic profile. We interpret this area, now located at the edge of the south-western Scotia Sea, as a relict of ocean-like crust formed during an earlier, possibly diffuse and disorganized episode of spreading at the first onset of the Drake Passage opening. The successive episode of organized seafloor spreading responsible for the opening of the Drake Passage that definitively separated southern South America from the Antarctic Peninsula, instigated ridge-push forces that can account for the subduction-related structures found along the western part of the South Scotia Ridge. This seafloor accretion phase occurred from 27 to about 10 Ma, when spreading stopped in the western Scotia Sea Ridge, as resulted from the identification of the marine magnetic anomalies.     

Dynamic Response Analysis of Interaction System of R.C. Gravity Single-Leg Platform

In this paper, the responses of the interaction system of R.C. gravity single-leg platform to seismic excitation are mainly analysed. A set of nonlinear equations for the interaction system are established by using the wave, one is the soil-structure interaction and the other is the fluid-structure interaction. The seismic response of the interaction system is analysed for the influence of the asymmetric structure, fluid action, etc. with the input of seismic SH waves in any direction. The numerical results are given for a simple example.     

台湾及其邻海的重力特征与构造、地震的关系

分析认为，在台湾及其邻海的重力场中，具有短波长特征的空间重力异常受地形与海深所制约．玉山的200×10     

Gravity torques for surface waves

The effects of the gravity torques acting on the angular momentum of surface gravity waves are calculated theoretically. For short crested waves the gravity torque is caused by the force of gravity on the orbiting fluid particles acting down the slopes of the crests and troughs and in the direction parallel to the crests and troughs. The gravity torque tries to rotate the angular momentum vectors, and thus the waves themselves, counterclockwise in the horizontal plane, as viewed from above, in both hemispheres. The amount of rotation per unit time is computed to be significant assuming reasonable values for the along-crest and trough slopes for waves in a storm area. The gravity torque has a frequency which is double the frequency of the waves. For long crested waves the gravity torque acts in the vertical plane of the orbit and tries to decelerate the particles when they rise and accelerate them when they fall. By disrupting the horizontal cyclostrophic balance of forces on the fluid particles (centrifugal force versus pressure force) the gravity torque accounts qualitatively for the three characteristics of breaking waves: that they break at the surface, that they break at the crest, and that the crest breaks in the direction of wave propagation.     

Research on Characteristics of Density Current Under the Action of Waves

In this paper,the characteristics of density current under the action of waves are describedwith the help of flume experiment and theoretical analysis.The study shows that turbid water under the ac-tion of the waves can present three types of motion,i.e.significant stratification,fragile stratification andstrong mixing.The motion of turbid water presents significant stratification when(H/D)/△ρ/ρ~(1/2)≤4.5,generally this state is known as density current.The formulas of motionvelocity,thickness,and discharge of density current moving on horizontal bottom are derived by use of ba-sic equations such as momemtum equation,equation of energy conservation and continuity equation offluid.The time-average velocity and the thickness of density current under the action of waves have a rela-tionship with such parameters as relative density(△ρ/ρ),wave height(H),and water depth(D).Whenthese parameters are determined,the time-average thickness and motion velocity of density current are al-so determined.The relat     

波浪作用下异重流运动特性研究

本文通过水槽试验和理论分析手段对波浪作用下异重流运动特性进行了研究，应用流体运动基本方程推导了异重流在水平底面运动时的运动速度、厚度和流量表达式。结果表明，计算结果与水槽试验较一致     

渤、黄海假潮的气象学成因

对渤、黄海14个主要海湾的原始验潮记录进行了分析，从中筛选出水位变化幅度大于或等于50cm的54个假潮个例，着重分析了伴随假潮过程的天气形势，把可能引发假潮的天气形势归纳为4种基本类型。分析结果显示：绝大多数（92％）引发假潮的天气个例都与锋面活动有关；所有个例中低层大气基本上都是弱静力稳定，且都具有较强的垂直风速切变。根据观测事实和稳定度理论分析认为，低层大气的弱静力稳定层结构以及由垂直风速切变引起的剪切不稳定性，是假潮气象学成因的一种必要条件和物理机制。     

南海罗斯贝变形半径的地理及季节变化

根据南海 1°× 1°网格的标准层季节平均温、盐度资料 ,在未引入Boussinesq近似条件下 ,采用改进的Thompson Haskell算法求解线性化斜压海洋水平大尺度波的垂直结构方程 (重力内波方程 ) ,从而得到了南海各网格点的第一斜压重力波相速度和相应的罗斯贝变形半径 ,并探讨其地理分布和季节变化特征 ,以期有助于南海环流和中尺度涡旋以及有关海洋侧边界效应的研究。