新疆塔里木北部地区压,扭,张破裂面分维数D值测算

本文精测了新疆塔里木北部地区压、张、扭三类不同性质断层断面的起伏高度和长度,利用谢和平及Parisean(1994)的公式,测算了断面分维数D,又由D值测算了粗糙度JRC值,发现压、张、扭三类断层的D和JRC值有明显差别,所取得D值与美国的San Andrees断层的D值具有一定的相似性。     

人工冻土声波参数试验研究

用ＳＹＣ－２型声波探测仪，对取自淮南矿区井下冻粘土，冻砂土进行了测定。其声波纵横波速振幅衰减系数及动弹模与冻土温度、含水量、容重的关系均用于幂指数形式较好地描述。其中容波速，动弹模及振衰减的影响最大；其次为温度、含水量；冻土振幅度衰减系数对其物理参数变化的敏感性大于波速。另外还研究了冻粘土与冻砂土怕波特性差异、截载大小及加载时间对冻土怕特性影响。     

岩石样品U0和ΔU的计算

本文给岩石原始铀含量和铀变化系数以确切定义 ,并系统介绍了U0 和ΔU的计算方法。计算岩石原始铀含量 (U0 )有Th/U比值法和U Pb同位素法 ,后者又包括两阶段法和三阶段法 ;铀的变化系数 (ΔU)包括近代 (现代 )和成矿时铀的变化。这一手段或方法对研究地浸砂岩型铀矿成矿机理和成矿预测有重要意义。     

黄河郑州—济南段河型变化特征及其与隐伏断层活动的关系

厚层松散堆积区（盆地或平原等）发震断层多以隐伏活动为主要特征,基于上断点的传统活动断层探测技术通常难以约束断层最新活动性质和时代。利用冲积河流对地表形变的敏感性评估断层活动性,是极具潜力的隐伏活动断层研究方向。本文基于TM/ETM遥感影像,对小浪底水库建设前后（1990~2013年）郑州—济南段黄河水域多期次几何特征进行提取和分段,共获取6个时期河道中心线弯曲度和5个时段河道面积重叠率的沿程变化信息。与区域资料对比的结果表明,弯曲度异常高值段在空间分布上除个别临近运河穿越处外,主要与穿黄或临黄隐伏断层相对应;在综合分析各种潜在因素后,认为与相关隐伏断层活动引起的地表形变有关。多时段重叠率均值整体上顺流增大（趋于稳定）,局部异常低值（不稳定）指示加积段落,在空间上与弯曲度分析指示的构造变形信息一致。本研究表明相关指标多期均值能较好地反映局部因素引起的河型异常,为认识和评价相关穿黄、临黄断层（新乡—商丘断裂、黄河断裂、聊城—兰考断裂、曹县断裂、巨野断裂及郑州—开封断裂）的活动性和地震危险性提供了独立的解释和评价依据,可为利用河型异常特征分析同类地区隐伏断层活动性和河段稳定性提供技术支撑。     

黄河郑州—济南段河型变化特征及其与隐伏断层活动的关系

厚层松散堆积区（盆地或平原等）发震断层多以隐伏活动为主要特征,基于上断点的传统活动断层探测技术通常难以约束断层最新活动性质和时代。利用冲积河流对地表形变的敏感性评估断层活动性,是极具潜力的隐伏活动断层研究方向。本文基于TM/ETM遥感影像,对小浪底水库建设前后（1990~2013年）郑州—济南段黄河水域多期次几何特征进行提取和分段,共获取6个时期河道中心线弯曲度和5个时段河道面积重叠率的沿程变化信息。与区域资料对比的结果表明,弯曲度异常高值段在空间分布上除个别临近运河穿越处外,主要与穿黄或临黄隐伏断层相对应;在综合分析各种潜在因素后,认为与相关隐伏断层活动引起的地表形变有关。多时段重叠率均值整体上顺流增大（趋于稳定）,局部异常低值（不稳定）指示加积段落,在空间上与弯曲度分析指示的构造变形信息一致。本研究表明相关指标多期均值能较好地反映局部因素引起的河型异常,为认识和评价相关穿黄、临黄断层（新乡—商丘断裂、黄河断裂、聊城—兰考断裂、曹县断裂、巨野断裂及郑州—开封断裂）的活动性和地震危险性提供了独立的解释和评价依据,可为利用河型异常特征分析同类地区隐伏断层活动性和河段稳定性提供技术支撑。     

Biotic forcing militates against river meandering in the modern Bonneville Basin of Utah

Biotic forcing on river meandering is a highly debated topic in sedimentology. Vegetation is assumed to hold a vital role on channel stability and sinuosity, for example through bank stabilization and pedogenic production of cohesive clays. However, statistically solid and causal relationships between vegetation density and river sinuosity remain largely untested in natural systems. This study investigates physical and biotic forcings on channel sinuosity in the Bonneville Basin of Utah (USA), an endorheic depression flanked by active fluvial networks (‘washes’) that display diverse vegetation density and channel‐planform style. By means of remote sensing and ground‐data collection, 58 washes are considered, 0·1 to 90 km² in surface area and drained by trunk channels <45 m wide and <1·2 m deep. Each wash is composed of a catchment basin connected downstream to an aggradational and distributive channel network. Statistically solid regressions highlight the primary roles played by base level and catchment size on fluvial morphogenesis. In contrast, no correlation is found between vegetation density and other parameters such as trunk‐channel width or surface area of the largest meander in a wash. Similarly, no statistical correlation exists between vegetation density and meander size or sinuosity index. Rather, larger and more sinuous meanders are invariably associated with lower vegetation density. These results are corroborated by field evidence showing that sparse vegetation promotes flow disturbance, channel branching and bar braiding instead of stabilizing sediment surfaces. Thus, river meandering is attributed to cohesion offered by mud retention within the endorheic basin, as well as discharge and stream‐power modulation along bifurcating and low‐gradient channel reaches. Hence, this work demonstrates how meandering‐channel patterns may arise from entirely physical forcings in the absence of vegetation.     

杏北油田低弯度分流河道储层构型及其控制的剩余油分布模式

低弯度分流河道储层是杏北油田的重要储层类型,深入研究其储层构型特征对于油田调整挖潜意义重大。综合密井网岩心、测井和生产动态等资料,采用“层次分析和模式指导”的方法,分“复合河道和溢岸砂体、单期河道及其相互接触关系”两个主要层次开展储层构型精细解剖,构建了三维储层构型模型。基于密闭取心井、水淹层测井解释资料和生产动态数据分析了不同时期的水淹特征和剩余油分布,并通过基于三维构型模型的油藏数值模拟对剩余油分布模式进行验证,最终总结出不同储层构型控制下的剩余油富集模式。结果表明,在河道内,剩余油在顶部、边部、河道间夹层控制部位以下以及仅与低渗溢岸砂连通造成注采不完善的河道内部富集;在河道外,剩余油在河间物性较差的溢岸砂内、注采不完善的溢岸砂末端和孤立砂体内富集。     

工作面断层破坏指数的最优形式及其统计预测

根据平顶山矿务局大量历史开采资料,运用统计分析方法,取得影响开采的主要断层因素,提出了断层破坏指数的最优形式;研究了工作面断层破坏指数的统计预测方法和公式;建立了断层破坏指数与开采指标的关系模型。这些成果对采矿设计与计划、对目标定额确定与管理等具有积极作用。      

Assessing the oscillation of channel geometry and meander migration cardinality of Bhagirathi River,West Bengal,India

Journal of Geographical Sciences - Lateral migration of the Bhagirathi River temporally creates unavoidable geomorphic hazards in West Bengal, India. The Bhagirathi River flows SW for ~67.30 km...     

Environmental reconstructions of a late devensian terrace sequence. Some preliminary findings

Facies analysis of Severn Main terrace sediments at Eardington, Shropshire is instructive in determining aspects of the sedimentary environment at a ‘proximal’ location in the terrace. Evaluation of the structural and directional properties of the gravels indicates that the terrace is a composite feature comprising two units. The lower unit is notable for the widespread occurrence of large sandy facies, a near absence of massive gravel facies, and the presence of large, locally derived, lithoclasts in excess of 1 m in diameter. Facies associations observed indicate the existence of in-channel bars and large channels with bedforms at the dune-plane bed transition. The directional properties of the unit indicate flows parallel to the main valley axis and although the unit is unlike previously reported examples it is interpreted as being the product of a proximal low sinuosity environment. The upper unit is composed mainly of multistorey, coarse, massive gravel units with limited interbedded sand facies. Fabric analysis indicates progradation of the unit from the west. The facies sequence is similar to those encompassed by facies models proposed for proximal alluvial fan deposits and therefore, on structural and directional grounds, the upper unit is interpreted as an alluvial fan deposit which prograded into the main Severn valley from the adjacent Mor Brook tributary. The implications of the composite nature of the terrace at this point are considered both in terms of terrace correlation and palaeohyrological estimation.