三角剪切断层传播褶皱在祁连山北缘断裂中的应用:以黑河口断层为例

逆冲断层运动学过程研究可为造山作用和盆地演化提供重要的信息。位于青藏高原东北缘的祁连山北缘逆冲断裂（NFT）是一条主要的边界断裂,控制着祁连山晚新生代以来的隆升变形,但对于该断裂系统的运动学过程缺乏研究。甘肃张掖西南莺落峡附近,黑河口断层（祁连山北缘断裂的一部分）穿过红沙沟并导致其阶地面错断和褶皱变形。为了研究该区域褶皱变形特征和断层运动学过程,我们首先在红沙沟区域进行了详细的野外考察并对变形的地层和阶地面进行了测量,然后通过数值模拟方法来验证褶皱模型。红沙沟保存有9级河流阶地,利用差分GPS对阶地面的高程进行了测量,同时在野外测量了部分地层的产状。多处断层剖面表明该区域变形属于基底卷入的构造类型,另外变形的阶地面在近断层处表现出明显的褶皱形态。结合阶地面变形特征以及地层的变形,三角剪切断层传播褶皱模型被初步用于该区域构造变形的解释。模型模拟得到自T5、T6和T7形成以来断层滑动量分别是 44±7m、59±10m和 164±28m;结合T6年代得到自约9万年以来该断层的平均滑动速率为 0.68±0.19mm/a,垂直分量为 0.58±0.13mm/a。根据地层与阶地变形特征,并结合模型模拟结果,我们认为祁连山山前基底断层卷入的构造中,在断层出露地表之前,断层顶端存在一个分散式的三角形变形区,区域的应力状态控制着下伏地层和上覆地貌面的褶皱变形。     

南海上层经向翻转环流的低频变化

The low-frequency variability of the shallow meridional overturning circulation(MOC) in the South China Sea(SCS) is investigated using a Simple Ocean Data Assimilation(SODA) product for the period of 1900–2010. A dynamical decomposition method is used in which the MOC is decomposed into the Ekman, external mode, and vertical shear components. Results show that all the three dynamical components contribute to the formation of the seasonal and annual mean shallow MOC in the SCS. The shallow MOC in the SCS consists of two cells: a clockwise cell in the south and an anticlockwise cell in the north; the former is controlled by the Ekman flow and the latter is dominated by the external barotropic flow, with the contribution of the vertical shear being to reduce the magnitude of both cells. In addition, the strength of the MOC in the south is found to have a falling trend over the past century, due mainly to a weakening of the Luzon Strait transport(LST) that reduces the transport of the external component. Further analysis suggests that the weakening of the LST is closely related to a weakening of the westerly wind anomalies over the equatorial Pacific, which leads to a southward shift of the North Equatorial Current(NEC) bifurcation and thus a stronger transport of the Kuroshio east of Luzon.     

一种基于数据质量分析的改进TurboEdit方法

针对TurboEdit方法中Geometry-Free(GF)组合拟合窗口、Melbourne-Wübbena(MW)组合中误差求取窗口过大造成小周跳探测不敏感的问题,通过对观测数据进行质量分析自适应设置GF组合和MW组合窗口,重新构造周跳检测量进行周跳探测,并利用搜索法解决修复失败历元的周跳修复问题。利用GPS和BDS实测双频数据对改进方法进行验证,实验结果表明本方法能准确探测到1周的小周跳,经搜索后周跳修复成功率提高至100%。     

基于ROMS模型数值研究南海温跃层的季节变化

On the basis of the regional ocean modeling system （ROMS）, the seasonal variations of the thermocline in the South China Sea （SCS） were numerically investigated. The simulated hydrodynamics are in accordance with previous studies： the circulation pattern in the SCS is cyclonic in winter and anticyclonic in summer, and such a change is mostly driven by the monsoon winds. The errors between the modeled temperature profiles and the observations obtained by cruises are quite small in the upper layers of the ocean, indicating that the ocean status is reasonably simulated. On the basis of the shapes of the vertical temperature profiles, five thermocline types （shallow thermocline, deep thermocline, hybrid thermocline, double thermocline, and multiple thermocline） are defined herein. In winter, when the northeasterly monsoon prevails, most shallow shelf seas in the northwest of the SCS are well mixed, and there is no obvious thermocline. The deep region generally has a deep thermocline, and the hybrid or double thermocline often occurs in the areas near the cold eddy in the south of the SCS. In summer, when the southwesterly monsoon prevails, the shelf sea area with a shallow thermocline greatly expands. The distribution of different thermocline types shows a relationship with ocean bathymetry： from shallow to deep waters, the thermocline types generally change from shallow or hybrid to deep thermocline, and the double or multiple thermocline usually occurs in the steep regions. The seasonal variations of the three major thermocline characteristics （the upper bound depth, thickness, and intensity） are also discussed. Since the SCS is also an area where tropical cyclones frequently occur, the response of thermocline to a typhoon process in a short time scale is also analyzed.     

北黄海盆地东部坳陷火成岩地震相识别与分布预测

北黄海盆地东部坳陷火成岩分布复杂并具有多期性,直接影响了油气成藏作用,然而目前对其空间分布尚缺乏深入认识,制约着该区勘探开发的部署。利用全三维地震资料,根据地震反射特征识别出了不同类型的火成岩地震相模式,并对其不同特征进行了分析,通过地震相识别进行平面追踪,结合时间切片三维地震技术及属性分析对火成岩分布进行了预测。结果表明,北黄海盆地东部坳陷主要发育柱状、尖峰状、蘑菇状和丘状4种火成岩反射地震相;研究区火成岩分区性较明显,主要发育3处火成岩体,分别位于东部隆起剥蚀区、坳陷中部和坳陷的西北部。     

末次间冰期衰退时期的北大西洋海流和欧洲环境

北大西洋海流是大洋循环的重要组成部分，将热带的热量从墨西哥湾传输到北大西洋北部。这些热量被释放进向东移动的气团中，极大地改善了欧洲北部的冬季气候。我们通过模式模拟预测出：随着CO2浓度的持续增加(IPCC第3个评价报告：气候变化，2001)，下个世纪的大洋循环会极大地减弱。自从20世纪60年代早期以来，我们开始观察到由于来自Nordic海的流量减少，北大西洋北部的海水不断淡化(Hansen等，2001；Dickson等，2002)。     

北太平洋风海流季节变化的数值模拟

用绝热表层风海流模式,以1949～1979年COADS资料,研究北太平洋表层风海流及相应水位场随季节变化的特点、某些特定年表层风海流的异常。模式采用二次动量守恒的有限差分方法,保证了计算稳定性。在数值积分中考虑了陆界、水界条件和近岸地形对风海流及水位场的影响。计算表明:模式反映了北太平洋主要流系的季节变化规律,能较敏感地反映上层海洋对大气动力作用的响应。给出了北太平洋主要流系的强弱与黑潮大弯曲的对应关系。     

基于多数据集的菲律宾海深层环流研究

本文使用多套再分数据、气候态数据和模式模拟结果对菲律宾海深层环流进行了研究,同时结合断面观测数据评估了这些数据集对于菲律宾海深层水团与环流分析的适用性。结果显示,气候态数据的温盐结构与断面观测结果较为一致,较适于用来进行菲律宾海深层水团气候态特征的研究。多个非气候态资料的数据集中混合坐标模型(Hybrid coordinate ocean model GLBa0.08)数据中的温盐结构与观测相对较为接近,也可用于开展菲律宾海深层水团研究。海洋与气候环流模型(Estimating the circulation and climate of the ocean Version 2)数据与菲律宾海深层环流的观测研究吻合相对较好。通过对比分析多个数据集,结合前人研究成果,显示在菲律宾海的2 000～4 000 m层,深层水会从雅浦-马里亚纳深水通道(Yap-Mariana junction, YMJ)处入侵到菲律宾海深层,并跨过九州-帕拉海脊(Kyushu-Palau Ridge, KPR),在菲律宾海盆(Philippine Basin, PB)的南部和北部形成气旋式环流;深层水还会通过伊...     

昭君坟、石崖城与达拉特旗段黄河——关于《中国历史地图集》相关注记的考疏

鄂尔多斯达拉特旗的昭君坟,又称昭君岛,是著名的昭君疑冢之一。去年7月,应景区管理者的邀请,去那里参加昭君坟旅游开发论证,使我有了一次就近游览的机会。