渭河断裂窖店浅层地震与钻孔联合剖面研究

为确定渭河断裂中部隐伏段的位置,在咸阳窑店布设了浅层地震勘探测线,在浅层地震勘探资料对断层解译的基础上,进一步开展了窑店和陈家沟钻孔联合剖面勘探工作,详细查明了渭河断裂的精确位置和组合特征,结合钻孔土样光释光(OSL)年龄测试和区域地层资料,深入研究了渭河断裂带最新活动年代和滑动速率等特征。     

东南印度洋各锋位置和走向的季节变化及其与风场变化的关系

利用剖面浮标的温盐观测资料和上层温度观测资料以及ECCO风应力数据研究了东南印度洋各主要海洋锋的位置、走向和风场的季节变化,并初步分析了亚热带锋(STF)和亚南极锋(SAF)的成锋机制.季节平均的夏季和冬季厄加勒斯锋(AF)分别可以延伸到80°E和82°E,AF在多数情况下可能与SAF和南亚热带锋(SSTF)汇合共同通过Kerguelen-Amsterdam Passage.在克尔盖伦海台以东海盆区,冬季SAF和PF的路径均比夏季偏南,在其他海域二者路径的季节差别不大.克尔盖伦海台以东的深海盆由北向南正负风应力旋度高值中心交替出现,且位置季节变化很小.85°~105°E之间零风应力旋度线位置冬季比夏季偏北.STF位于辐聚区,埃克曼抽吸导致的表层水辐聚可能是STF产生和维持的原因.SAF位置的季节南北摆动幅度小于风应力零旋度线的季节摆动幅度,夏季SAF位置略偏于风应力正旋度区,而冬季大多位于负旋度区,因此风应力旋度不是SAF形成的直接原因.     

Detailed measurements of thickness and grain size of a widespread onshore tsunami deposit in Phang‐nga Province,southwestern Thailand

Measurements of thickness and grain size along flow‐parallel transects across onshore deposits of the 2004 Indian Ocean tsunami revealed macroscopic horizontal variations and provided new insights into tsunami sedimentation. The tsunami caused severe erosion of beaches, river mouths, and the shallow seafloor along the coast of southwestern Thailand and supplied sufficient sediment to deposit a kilometer‐wide blanket of sand on the land surface. The tsunami deposits generally fine landward with some fluctuations caused by local entrainment and settlement of sediments. Sediments of medium and fine sand are restricted to a few hundreds of meters inland from their source, whereas finer grained sediments were suspended longer and deposited 1 km or more inland. Although the thickness of the tsunami deposits is strongly influenced by local topography, they generally thin landward. In areas of low‐relief topography, the rate of landward thinning is exponential and reflects the dominance of sediment supply to nearshore areas over that to areas farther inland.     

Magnetotelluric study of the Xuefeng mountain area,Hu’nan Province,China

A magnetotelluric study was carried out in the Xuefeng mountain uplift belt and its western margins. A detailed investigation was made of the resistivity of the formations, and reliable data were obtained. The sedimentary cover and basement structure of the Xuefeng mountain area and the deep geological structure were analyzed in detail using magnetotelluric data from the two-dimensional inversion of the resistivity profile data in combination with regional gravity and magnetic data. It was concluded that the tectonic movements were characterized by basement detachment, and north-south ramp. The study area can be divided into a southern uplift zone, a southern thrust-faulted zone, a central uplift zone, and a northern depression zone. This work has provided geophysical evidence that can be used in future studies of the tectonics and petroleum geology of this region.     

丹麦海峡海洋锋时空变化特征研究

丹麦海峡海洋锋可为局地气候变化、海峡鱼类分布以及海峡中尺度涡等方面研究提供参考,在军事领域也具有较高应用价值。然而目前国内外缺乏对于丹麦海峡锋的系统研究。本文利用WOA13数据,对丹麦海峡锋位置、强度空间分布以及相应的季节变化进行了分析。结果显示,锋轴线位置在34°W以西150 m以浅相对稳定,34°W以东锋轴线随深度和季节均有摆动。锋强度在水平和垂直方向分布不均匀,水平方向上锋轴线最大值与最小值差值一般在3倍以上。垂直方向盐度锋主要集中在100 m以浅,且强度随深度不断减小;温度锋强度最大值在表层以下且在300 m以深随深度增加锋强度减小,但有一些区域如27°W和28°W附近,受到海底地形的影响温度锋强度随着深度的变化有大幅度增加的特点。     

基于观测系统模拟试验的海表气象观测站点布局方案研究

为了科学设计黄渤海海洋气象边界层观测站网并研究观测网布局对数值天气预报模式的影响,本文采用模式误差、海洋气象要素特征区域资料统计分析和观测系统模拟试验（OSSE）方法,根据边界层雾、层云降水、小风与中等风速天气条件设计布局方案,并分析站点观测要素对数值预报模式的要素预报的影响。模拟试验数据使用了每6 h NCEP再分析资料FNL（NCEP Final Operational Global Analysis data）、NCEP每天平均的高分辨率海温资料RTG_SST（Real-Time Global Sea Surface Temperature）和石油平台、浮标站等每小时实况观测资料,评估了黄渤海海洋气象站网布局各个方案的优缺点。评估结果表明,湿度和风的要素预报受实况风向风速条件影响,偏东和偏北风个例湿度要素预报较好。然而,在偏南中等风速个例中,风场预报要素更接近实况。温度场的分析综合结果显示,在海气相互作用影响较大的天气过程中,特征区域布站能明显提高温度要素的预报准确率。最后,综合分析多项模拟试验的结果,给出了改进数值预报准确率的海洋布站建议。     

爆破法处理武定工地埋钻事故

绳索取心钻探时,斜孔钻进发生的埋钻事故较难处理,在松软易碎地层中埋钻事故又极难预防。经多年实践,提出事故发生后采取优化钻孔井身结构,结合爆破法处理有效省时,节约成本又减少损失。     

云南锑（金）成矿带划分及有关成矿问题讨论

云南可划分11个锑（金）成矿带（区）。Sb—Au属同一成矿系列（Sb略晚）,二者常相伴产出。滇东坡脚组（D1p）与滇西三合洞组（T3s）,同为锑矿矿源层。滇东南与黔西区玄武岩喷溢早期的大厂层（P3d）、主期玄武岩组（P3β）、晚期龙潭组（P3l）,三者含Sb、Au背景值远高于全球玄武岩,构成统一的Sb—Au矿源层（岩）,在有利构造条件下,产出Sb矿（伴生Au）、Au矿（伴生Sb）或二者共存（广南堂上）,其成因都与幔源玄武岩喷溢作用有关。     

Pacific superplume-related oceanic basalts hosted by accretionary complexes of Central Asia, Russian Far East and Japan

Plume-related oceanic magmatism form oceanic islands, seamounts and plateaus (hereafter “seamounts” or “paleoseamounts”), which are important features in geological history. The accretion of oceanic seamounts to active continental margins significantly contributed to the formation of the continental crust. This paper reviews occurrences of Late Neoproterozoic–Mesozoic seamounts of the Paleo-Asian and Paleo-Pacific oceans, which are hosted by accretionary complexes (ACs) of Russian Altai, East Kazakhstan, Mongolia, Russian Far East and Japan. The paleoseamounts commonly consist of Ti–LREE–Nb-enriched plume-related basalts (OIB-type or intraplate basalts) capped with massive limestone and associated with other units of oceanic plate stratigraphy (OPS): oceanic floor basalts (MORB), pelagic chert, epiclastic slope facies, etc. The paper presents available geochemical data on the plume-related basalts including the first geochemical data on the Middle Paleozoic OIB-type basalts of the Paleo-Asian Ocean hosted by the Ulaanbaatar AC of Mongolia. An emphasis is made for the structural setting of OPS units, specific geochemical features of intraplate basalts, problems of their identification, and distinguishing from magmatic units of a different origin such as MORB, island-arc and back-arc basalts. Finally, we propose a continuous, though periodical, evolution of the Pacific superplume-related magmatism, which can be more reliably proved by studying Middle Paleozoic OPS units hosted by ACs of Mongolia and Tien Shan, and discuss prospects of future studies.     

Marine GIS: Identification of mesoscale oceanic thermal fronts

A new method (the ‘sink’ method) is proposed for the mapping of productive mesoscale oceanic thermal fronts based on the combined analysis of satellite imagery for sea surface temperature (SST) distribution and chlorophyll (CHL) concentration under a Geographic Information System (GIS). In an SST lattice data array, data value sinks describe heterogeneous drops in SST distribution as this is compared to more homogeneously distributed SST in the surrounding area. Using Arc/Info GIS, these thermal discontinuities are flagged and applied on SST and CHL imagery for the calculation of differences in SST and CHL patterns (DSST and DCHL) inside and outside of these flagged areas. Spatially connected sinks that are characterized by simultaneous negative DSST and positive DCHL pattern are mapped as thermal fronts. Results include a time series of monthly front occurrence GIS maps in Eastern Mediterranean waters along with three calculated front characteristics (DSST, DCHL and bathymetry). Comparisons between the mapped fronts and isobath distributions present clearly visible front‐to‐isobath spatial and shape associations while spatial analysis between front and wind data explains 66% of the number of mapped fronts.