Researches on Plants from the Lower Devonian Xujiachong Formation in the Qujing District, Eastern Yunnan

Fossil plants Hedeia sinica Hao et Gensel 1998, Huia gracilis Wang et Hao 2001 and Guangnania cuneata Wang et Hao are described from the Lower Devonian Xujiachong Formation, the Qujing district, eastern Yunnan, China. They contribute to our knowledge of the flora in this district. Based on the occurrence of common plants (Hedeia, Huia, Guangnania and Zosterophyllum australianum) and their horizons, it is proved for the first time that the mid-lower assemblage of the Xujiachong flora is comparable with the Early Devonian ((late) Pragian) Posongchong flora of southeastern Yunnan and the upper Baragwanathia flora of Australia. In view of this fact and the stratigraphic sequence, the mid-lower part of the Xujiachong Formation is considered to be of (late) Pragian age. Through comprehensive analyses of plant, bivalve and fish assemblages and the lithology, the upper part of the Xujiachong Formation is dated to be of early Emsian age. The Xujiachong flora belonged to the northeastern Gondwana palaeophytogeogr     

Characteristics and Genetic Analysis of the Deep-buried Weathered-crust Karst Hydrocarbon Reservoirs of the Lower Paleozoic Group in the Tarim Basin

The genetic analysis of the deep-buried reservoirs of the Lower Paleozoic carbonate rocks in the Tarim basin is a difficult task involving many factors. Firstly, the object of study is carbonate rocks, which have undergone a long term of modification. Secondly, the rocks are deeply buried with depths of 3800-7000 m in the Tarim basin. The primary reservoir properties formed in the deposition have been strongly modified during the deep burial process. Concurrently, the different burial depths in different areas result in diversities of burial temperature, pressure, underground water, hydrochemistry and various physicochemical changes, which further lead to differences in the diagenetic type, diagenetic property, diagenetic degree and their impacts on the reservoir properties. The Lower Paleozoic Cambrian and Ordovician carbonate reservoirs in the Tarim basin can be grouped into four types, i.e., paleo-weathered-crust reservoirs, reef reservoirs, buried karst reservoirs and dolomite reservoirs. This paper     

塔里木盆地晚泥盆世及石炭纪岩相古地理

塔里木盆地上泥盆统及石炭系包括5个组，自下而上分别为上泥盆统东河塘组和甘木里克组，石炭系巴楚组、卡拉沙依组和小海子组。其中东河塘组和甘木里克组地质时代为晚泥盆世，巴楚组地质时代为早石炭世杜内早中期，卡拉沙依组地质时代为晚杜内中期至巴什基尔期，小海子组地层时代为巴什基尔末期至莫斯科早期。岩石类型有碎屑岩和碳酸盐岩，还有膏盐岩，并夹薄层火山碎屑岩。沉积相主要为海陆过渡相组合，包括河流、三角洲、滨岸、浅海、碳酸盐岩台地、台地边缘6种相和12种亚相及33种微相。晚泥盆世东河塘期至石炭纪发生过4次较大的海侵，海侵范围由下而上逐渐增大，至晚石炭世小海子期海侵规模最大。东河塘期开始海侵，海水由西而东侵入，此时周缘碎屑物质供应充分，主要为无障壁海岸和障壁海岸沉积，西南缘为浅海相沉积。巴楚期晚期，海侵范围进一步扩大，物源向北或北东方向退却，陆源碎屑物质注入急剧减少，形成了一套富含生屑的碳酸盐岩地层，发育了开阔台地和局限台地亚相沉积。卡拉沙依期中期海侵规模比巴楚期更大，海水深度加大，西部为开阔台地亚相沉积，其余地区为局限台地亚相沉积。卡拉沙依期晚期和小海子期海侵达最大，向东扩展，大部分地区为开阔台地亚相沉积，东部地区为局限台地亚相沉积，塔北大部分地区缺失。     

714SD多普勒雷达在强降水中的应用

本文针对近几年汕头地区出现的强降水天气，重点开展了多普勒天气雷达速度回波及其产品的应用研究，结合相应的天气背景、物理量变化对强度回波和速度场回波作一些分析，归纳总结出台风、冷锋锋面、暖切变、西南急流、脊后槽前辐合区、东风波等不同天气形势下强降水的类型及其回波特征，并尝试性地解释了一些特殊回波的风场结构和天气现象。     

顾及起始数据误差的双点测边交会的精度计算

推导了起始数据误差对双点测边交会定点精度影响的估算式，并依此给出顾及起始数据误差的点位精度计算公式。     

THE RELATIONSHIP BETWEEN THE MOVEMENT OF THE MEIYU/BAIU RAIN BELT AND THE PERIODIC NORTHWESTWARD PROPAGATION OF THE CONVECTIVE ACTIVITY FROM TROPICAL WEST PACIFIC

In order to investigate the effect of the factors in tower latitudes on Meiyu/Baiu front,adiagnostic analysis for the two cases during June to July of 1985 and 1986 was examined.We foundthat (1)when the tropical convective activity moves westward to 10.5-15.5′N/140°E from eastside of 10.5-15.5°N/160°E,the northward shifts of the Meiyu/Baiu rain belt occurs;(2)themain factor which results in the northward and southward shifts of Meiyu/Baiu rain belt is thoughtas the 8,18 and 30 day oscillations of the tropical convective activity around West Pacific.Meanwhile,the wave train propagating from Lake Baikal via Okhotsk Sea to the tropics couldsometimes shift Baiu rain belt southward;(3)the onsets of Meiyu in China of both cases tend totake place just when the convective activity around lower latitudes moves westward through about140°E with the 8,18 and 30 day oscillation periods firstly coming to June.     

INVESTIGATION ON GEOSTROPHIC ADJUSTMENT,FRONTOGENESIS AND OSCILLATIONS

Geostrophic adjustment and frontogenesis are examined by means of the 2-D ARPS model.The simulation shows that.without the large-scale forcing,both the frontogenesis and frontolysisare observed during the geostrophic adjustment process and the intensity of the front oscillates inthe case of no discontinuity.The convergence (divergence) induced by the secondary circulation isthe most important factor for frontogenesis (frontolysis) at the top and bottom boundaries.Theamplitude and period of oscillation are dependent on the initial atmospheric stratification and theCoriolis frequency,and they are related to the inertio-gravity wave.     

平极长期漂移与地球平均下地幔黏性估计

利用9个国际纬度观测站的平纬长期变化序列,重新讨论并估计了平极的长期漂移,得到漂移的平均速率为(3.356“±0.142”)×l0-3/a,方向为西经78.7°±2.5°.进一步基于最新的ICE-4G冰期后地壳反弹模型,采用地球上8个冰盖的冰融参数,估计了理论的平极长期漂移方向为西经74.8°.由观测的平极长期漂移速率为约束,基于1066B地球模型,估计得到地球平均下地幔的黏性为vLM=(0.5-1.7)×1022Pa^.s,表明vLM应具有近1022Pa^.s量级,并认为地球平极的长期漂移很可能是由最近的21000年以来冰期后的地壳反弹所致.     

无线电掩星反演大气参数误差分析及应用进展

本文详细分析了影响空间GPS无线电掩星反演大气参数方法的主要误差源，其中包括信噪比误差，精密定轨误差，电离层模制误差，多路径效应和时钟改正等误差，并且介绍了国内外在无线电掩星领域的一些应用研究进展。