基于潜标观测的牛郎海山的深海海流的低频变化特征

本文利用在西太平洋牛郎海山布放的两套锚系潜标获取的长时间海流观测数据,分析了深海的海洋动力环境特征,着重阐释了该海域海流的全水深垂向结构及其低频变化特征。结果表明:（1）年平均海流及其变化幅度均在上层最大、中层和深层次之、中深层最小;（2）年平均上,150 m以浅的海流为东向的副热带逆流,150 m以深和中层为西向流;山顶处的近底层海流为较稳定的弱南向流,山底处的近底层海流为西南向流;（3）在山顶和山底,各深度层次的海流在全年均表现出100 d左右的振荡周期;在2 000 m以浅,各深度层次的海流振荡的位相基本一致,振荡幅度在表层最强、随深度的增加而减小;在2 000 m以深,海流变化的位相与2 000 m以浅相反,振荡幅度在4 000 m最强。     

基于图论法对城市水系连通性表征及优化

基于景观生态学中“点–边”数量关系建立水系环度（α）、节点连接率（β）和网络连通度（γ）3种水系连通性评价指标,绘制出南昌市水系“节点–廊道”有向图,并以城市湖水体引流化污为切入点来优化城市水系连通性。研究表明：① 南昌市城区水系存在廊道空间分布不均匀,湖节点与其他水系节点连接的廊道较少等问题;② 优化后的城区水系相较于现在水系,其中水系环度（α）提高75%,节点连接率（β）提高14.88%,网络连接度（γ）提高14.63%。在城市水系连通性优化中,不应过分追求连通性而盲目增加湖泊廊道,应在连通性与湖泊连接的廊道数量之间保持一个平衡关系,以免水体污染物在湖泊中淤积。     

庐山地区星子群碎屑锆石SIMS U-Pb年龄及其地质意义

江西庐山地区出露的星子群为一套遭受角闪岩相变质的中深变质岩系,前人将其划分为古元古代地层,并将其与华南早期地壳的形成与演化和中生代变质核杂岩构造相联系。本文通过对星子群浅粒岩中碎屑锆石U-Pb SIMS年代学研究,获得了(834±4)Ma碎屑锆石年龄,代表了该套地层沉积时代的下限;再结合其上覆筲箕洼组(830±5)Ma的火山岩年龄,将星子群的地层时代限定于新元古代。这一研究结果表明庐山地区并未出露古元古代的变质基底;而且野外也并未找到典型大规模拆离断层的存在,因此前人厘定的中生代变质核杂岩构造也值得商榷。根据碎屑锆石U-Pb不一致线下交点年龄为(133±20)Ma,推断星子群的变质作用发生在中生代。另外,由星子群单一的碎屑锆石年龄、锆石形态特征及矿物组成特征推断,星子群是源区花岗质岩石快速抬升、风化剥蚀和搬运沉积的产物,暗示着强烈的地壳运动过程,可能与Rodinia超大陆的裂解有关。     

Strengthened influence of the East Asian trough on spring extreme precipitation variability over eastern Southwest China after the late 1980s

The relationship between variations in the East Asian trough (EAT) intensity and spring extreme precipitation over Southwest China (SWC) during 1961–2020 is investigated. The results indicate that there is an interdecadal increase in the relationship between the EAT and spring extreme precipitation over eastern SWC around the late 1980s. During the latter period, the weak (strong) EAT corresponds to a strong and large-scale anomalous anticyclone (cyclone) over the East Asia–Northwest Pacific region. The EAT-related anomalous southerlies (northerlies) dominate eastern SWC, leading to significant upward (downward) motion and moisture convergence (divergence) over the region, providing favorable (unfavorable) dynamic and moisture conditions for extreme precipitation over eastern SWC. In contrast, during the former period, the EAT-related circulation anomalies are weak and cover a relatively smaller region, which cannot significantly affect the moisture and dynamic conditions over eastern SWC; therefore, the response in extreme precipitation over eastern SWC to EAT is weak over the period. The interdecadal change in the relationship between eastern SWC spring extreme precipitation and the EAT could be related to the interdecadal change in the EAT variability. The large (small) variability of the EAT is associated with significant (insignificant) changes in spring extreme precipitation over eastern SWC during the latter (former) period.摘要本文研究表明东亚大槽强度与中国西南地区东部春季极端降水的关系在20世纪80年代末后显著增强, 这可能与东亚大槽自身变率的年代际变化有关. 在80年代末之后, 东亚大槽的变率显著增强, 其对应的大气环流异常也偏强, 范围偏大, 可以显著影响西南地区东部的水汽和动力条件, 从而引起该地区春季极端降水的显著变化. 而在80年代末之前, 东亚大槽的变率偏弱, 其对应的大气环流异常也偏弱, 范围偏小, 因此不能对西南地区东部春季极端降水的变化产生显著影响.     

Genesis and Evolution of Structural Fracture in Tight Sandstone Reservoir of Keshen-2 Gas Field, Tarim Basin, NW China

<正>1 Introduction Keshen-2 gas field is located in the middle of KelasuIchicklick Structural Belt,Kuqa Depression,Tarim Basin,NW China.*The primary reservoir of Keshen-2 gas field is Bashijiqike Formation,Lower Cretaceous(K1bs),buried-6500~-7600 m.Exploration in this area has shown that structural fracture is the primary factor that improving     

The Zunhua-Zanhuang Ophiolitic Mélange: Traces of an Archean Suture in the North China Craton

<正>Sutures mark places where oceans have closed and two once widely separated terranes have collided.Sutures are defined on the basis of geological relationships,and differences in the geologic,structural,magmatic,sedimentary,and metamorphic histories of the terranes on either side of the suture.Sutures are characterized by     

沙尘观测仪器研发进展

沙尘的输移对于生态系统有重要的影响,沙尘观测是环境及气象因子观测、荒漠生态系统研究和荒漠化防治的重要环节。目前已有多种类型的风沙仪器用以观测风沙运动,但至今尚未解决精确测定难题。本文从水平通量和垂直通量两方面总结了国内外沙尘观测仪器的研发现状,比较了不同仪器的优缺点,指出了目前观测仪器研发存在的问题和未来发展趋势,提出了自动化和标准化是未来沙尘观测仪器研发目标的观点。     

云南会泽铅锌矿床外围高家阱勘查区构造样式与构造地球化学找矿

高家阱勘查区位于云南会泽铅锌矿床北东侧,是矿山厂断裂NE向延伸的有利成矿地段。在1∶5000构造地质填图基础上,结合典型构造面力学性质分析,认为高家阱勘查区受NE向矿山厂背斜、矿山厂断裂控制,NE向左行压扭性层间断裂是矿体赋存的有利部位。印支晚期,在NW—SE向应力持续作用下,形成NE向牵引褶皱,构成高家阱控岩控矿构造格架——逆冲推覆构造,为成矿流体的运移提供通道。通过蚀变指数计算,提取肉红色粗晶白云岩、米黄色粗晶白云岩、灰白色粗晶白云岩蚀变信息,划定3个强蚀变地段。通过构造地球化学因子分析,绘制Pb-Zn-Cd-Ag、As-Sb-Hg元素组合异常图,提取异常信息并圈定4个主要异常区。除石炭系外,异常还分布在震旦系、泥盆系,具多层位找矿潜力。综合控矿构造-矿化蚀变-构造地球化学勘查技术组合,提出找矿方向。     

Early Evolution of Marine Planktonic and Nektonic Ecosystems:Questions and Chinese Approaches

正The originations of marine planktons and nektons are significantly delayed than that of benthos,as evidenced by the fossil record.The Cambrian Explosion produced a variety of high-level marine organisms,and many remarkablebody-plans.However,a majority of these organisms are benthic or level-bottomed,and are rather dependent on the substrates of sea floors.This conclusion holds even with the giant predator     

环境温度对地震数据采集器时间精度的影响测试

为适应地震数据采集器时间精度测试的需要,采用特定电路将普通参考时钟源输出的分脉冲信号扩展至占空比为50％,再利用扩展后的分脉冲信号在室温、低温恒温及高温恒温环境中对地震数据采集器时间精度进行测试,研究环境温度对地震数据采集器时间精度的影响.结果表明,地震数据采集器时间精度及漂移趋势受环境温度变化影响,0.5 h内发生约...