辽河小洼油田东营组沉积环境条件的研究

陆相盆地沉积作用主要受构造作用及古气候的控制,所以从区域构造背景出发,结合地层、古生物、沉积、地球化学等方面资料.对小洼油田东营组的沉积环境条件进行综合分析.确定了沉积物源来自北东方向的中央凸起,古气候属于半干旱一半潮湿的温带气候条件。水介质是弱还原性的淡水滨浅湖泊沉积环境.此时中央凸起上丰富的风化剥蚀产物经过河流的搬运和分异作用,进入湖盆中形成三角洲沉积体。     

Characteristics of aeolian grain transport over a fluvio-glacial lacustrine braid delta,Lake Tekapo,New Zealand

This paper presents results from one of the few scientific studies to examine the physical characteristics of aeolian sediment transport in an alpine area, where topographically reinforced foehn winds initiate dust storm events. The major objective of this study is to improve knowledge of aeolian processes in mid-latitude alpine regions experiencing extreme wind speeds. Of particular interest is the role of surface characteristics in contributing to the unusually deep saltation layer which is seen to form over fluvio-glacial deposits in the Southern Alps of New Zealand. Sediment was collected at several heights (0ċ5, 1, 2 and 4 m) and locations over a large alpine braided river delta, and standard laboratory techniques used to examine grain size characteristics. An image processing technique was also used to evaluate grain roundness. Grains filtered from the airstream at 0ċ5 m and 1 m above such surfaces were found to display a mean grain size of approximately 300 to 435 μm, resembling grain size characteristics of saltation clouds previously observed in high latitude, cold climate locations, in contrast to desert and prairie environments. Samples collected at 2 and 4 m above the surface were found to consist of 60 to 65 per cent sand-sized material, with some grains exceeding 1–1ċ5 mm in diameter. Grain shape analysis conducted on silt- and clay-sized grains filtered from the airstream above mixed sand and gravel surfaces showed such grains to display an increase in grain roundness with height. This characteristic is thought to reflect the airstream's shape-sorting ability and has important implications with respect to the often observed increase in grain roundness in aeolian deposits with increasing distance from source areas. Namely, if more rounded grains are preferentially carried higher into the airstream and therefore into regions of higher wind speed, they should theoretically be transported further from the entrainment zone before being deposited. The high wind speeds observed, often exceeding 30 m s⁻¹, are seen to transport significantly larger sediment than reported in the literature for desert and prairie environments. In addition, the mixture of grain sizes, and especially the pebble- and cobble-sized clasts that dominate the fluvio-glacial deposits associated with the braided rivers in this mountain region, also appear to increase significantly the trajectory height of saltating sand grains. As a result of these two factors, the depth of the saltation cloud often exceeds 1 m. Observations made in this study therefore highlight the need for field and laboratory aeolian process studies to be extended to examine grain transport over coarse-grained beds during much higher wind velocities than typically reported in the literature. Such studies would provide a valuable insight into aeolian processes in high latitude/altitude environments, such as loess genesis. © 1997 by John Wiley & Sons, Ltd.     

黄河口海岸线遥感动态监测

本文以1976年至2002年间18景多时相遥感影像为主要数据源,在遥感与GIS技术的支持下,对影像进行几何校正与配准,并运用近红外波段的水体反射辐射率明显单一并低于其他地物的特性提取了逐年河口海岸的平均高潮线,另外经GIS叠加分析计算等获取了海岸线时空变化的数据,进一步分析了海岸线的演变过程,并根据河口来水来沙等条件提出了防止海岸蚀退的对策。     

青海砂西油田古近系下干柴沟组下部沉积相定量研究

随着油田开发难度的加大，开发中仅仅把储集砂体的沉积相类型确定下来是远远不够的，还要求准确地预测砂体的宽度、长度等定量参数，这就是本文所指的沉积相定量研究。本文根据大量钻井资料，在地层精细划分对比的基础上，对青海砂西油田E31辫状河三角洲平原和曲流河三角洲平原进行了定量研究，确定了分流河道砂体的宽度、宽/厚比等参数。研究表明，本区辫状河三角洲平原的分流河道砂体宽多为 1200-3000m，厚多为5-10m，宽/厚比200-280。曲流河三角洲平原的分流河道砂体宽多为 400-700m，厚多为3-6m，宽/厚比80-110。辫状分流河道砂体比曲流分流河道砂体普遍宽、厚是由于辫状分流河道频繁摆动改道引起砂体的横向拼合和垂向叠置所致。这种河道可称复合河道。利用“厚度中心法”可区分复合河道与单河道。由于不同沉积相的砂体宽度不同，在油田开发中井网部署方案应该不同。     

鄂尔多斯坳陷湖盆缓坡型三角洲前缘沉积微相分带及成因分析——以定边-安边地区延长组长6油组为例

运用沉积相分析理论对鄂尔多斯盆地定边-安边地区晚三叠世延长组坳陷湖盆缓坡型三角洲前缘沉积微相组合进行系统研究,共识别出其组合形式有:水下分流河道叠加组合、河口坝叠加组合、水下分流河道与河口坝叠加组合以及河口坝与远砂坝、席状砂的叠加组合等4大类9种类型。并深入研究三角洲前缘沉积微相组合的时空分布规律,以三角洲前缘坡折带为界,将三角洲前缘分为"台型前缘"、"坡型前缘"和"盆型前缘"三部分,各部分有独特的沉积微相组合形式。高分辨率层序地层学的基准面旋回原理和沉积物体积分配原理表明:短期基准面的规律性变化影响着储层砂体的成因类型、叠加组合形式和空间分布规律,据此建立坳陷湖盆三角洲前缘不同沉积微相组合的成因分布模式。     

The submarine eruption of the Bombarda volcano,Milos Island,Cyclades, Greece

The Milos volcanic field includes a well-exposed volcaniclastic succession which records a long history of submarine explosive volcanism. The Bombarda volcano, a rhyolitic monogenetic center, erupted ∼1.7 Ma at a depth <200 m below sea level. The aphyric products are represented by a volcaniclastic apron (up to 50 m thick) and a lava dome. The apron is composed of pale gray juvenile fragments and accessory lithic clasts ranging from ash to blocks. The juvenile clasts are highly vesicular to non-vesicular; the vesicles are dominantly tube vesicles. The volcaniclastic apron is made up of three fades: massive to normally graded pumice-lithic breccia, stratified pumice-lithic breccia, and laminated ash with pumice blocks. We interpret the apron beds to be the result of water-supported, volcaniclastic mass-How emplacement, derived directly from the collapse of a small-volume, subaqueous eruption column and from syn-eruptive, down-slope resedimentation of volcaniclastic debris. During this eruptive phase, the activity could have involved a complex combination of phreatomagmatic explosions and minor submarine effusion. The lava dome, emplaced later in the source area, is made up of flow-banded lava and separated from the apron by an obsidian carapace a few meters thick. The near-vertical orientation of the carapace suggests that the dome was intruded within the apron. Remobilization of pyroclastic debris could have been triggered by seismic activity and the lava dome emplacement. Published online: 30 January 2003 Editorial responsibility: J. McPhie     

辽河三角洲地貌演化(英文)

This paper mainly analyzes the geomorphological changes of the tidal deposition in the Liaohe Estuary based on the multi-year bathymetric charts in 1990, 1996, 2002 and 2005 and Landsat TM images in 1987, 1994, 2002 and 2005. Evolution of the tidal depositional system during the past 20 years in the Liaohe River was studied on the basis of 50 boreholes drilling and 30 km shallow stratigraphic exploration from 2002 to 2005. The main tidal depositional body of the modern Liaohe River delta is located in the Shuangtaizihe Estuary. The stratum within the depth of 10 m includes tidal bank facies, tidal channel facies and neritic facies with paleo-delta facies underlying them. The sediments of tidal bank facies are mainly composed of sand and silt with siltation load and suspended load of about 50% respectively in proportion. The sediment of tidal channel facies and neritic facies is composed of clayey silt and silty clay which belongs to suspended load. The study area was a small bay between the old Daliaohe River, the old Dalinghe River and the Raoyanghe River complex delta since the Holocene to 1896. Many tidal banks formed and expanded rapidly after the Shuangtaizihe River was excavated by labor in 1896. The runoff and sediment discharge have decreased since the construction of brake at the Shuangtaizihe River in 1958.The Shuangtaizihe Estuary is in the state of deposition as a whole whose tidal bank is increasing and expanding southward, westward and northward. The maximum expansion speed is 87 to 683 m/a and the mean depositional rate is 0.189 m/a. Erosion occurred in some part of tidal bank with average erosional rate of 0.122 m/a. The tidal channel was filled up with sediment at a migration speed of 48–200 m/a. Geomorphologic changes have happened under the combined influences of runoff, ocean dynamics and human activities. The main source of sediment changes from river sediment to sediment driven by tidal current and longshore current.     

现代黄河三角洲滨浅海区的灾害地质

利用卫星遥感、测深、浅地层剖面及钻孔资料研究了黄河三角洲海岸及近海海洋灾害地质,编制了黄河三角洲海洋灾害地质图。黄河三角洲海岸灾害地质以海岸侵蚀为主,根据1976—2001年海岸的变化速率,可将海岸分为快速侵蚀海岸、中等程度侵蚀海岸、稳定海岸和淤积海岸四类,快速侵蚀海岸和中等程度侵蚀海岸长期以来遭受侵蚀。灾害地质因素有浅层气、灾害地貌、活动断层、海底滑坡、底辟、隆起脊、埋藏冲沟一古河道。浅层气主要分布在老黄河口附近渤海海底,近岸少见。浅层灾害地貌主要分布在三角洲前缘斜坡上的扰动区。扰动区位置在整个三角洲上变动明显,有向岸移动的趋势,斜坡坡度减小,扰动强度减弱。底辟除了发生在废弃三角洲侵蚀区外,还发生在三角洲外的渤海海底下部。隆起脊位于黄河口东部渤海海底,沿NE—SW方向发育,顺隆起脊发育活动断层。     

黄河三角洲潮滩潮沟体系的分维特征

利用分形分维方法对黄河三角洲潮滩和潮沟的地貌特征进行了定量研究。结果表明，潮滩和潮沟的分维值可以较好地反映潮滩潮沟的发育演化规律。随着时间的推移和潮沟潮滩的进一步发育，黄河三角洲潮沟的分维值呈逐渐增大的趋势，而潮滩的分维值则呈逐渐减小的趋势，两者在分维值的变化上存在着负相关关系。该研究为黄河三角洲潮滩发育时空谱系的建立和深入研究提出了一种新方法和新的定量指标。     

渤海南部表层沉积的相特征

通过海上调查及实验室分析,查明渤海南部表层沉积物在结构类型、矿物组合、生物组分及沉积构造等相特征方面具有明显的分区性。渤海南部存在五种沉积相:黄河水下三角洲相、陆架盆地相、海湾相、潮流浅滩相及古滨岸相。黄河水下三角洲相从河口延至水深15—20米处,沉积速率很高,沉积物富含碎屑云母及CaCo_3。陆架盆地相的沉积为粉砂质粘土,具有生物扰动构造。