西藏羌塘西北部干枯沟地区早三叠世晚期碱性岩类的发现

碱性花岗岩分布于西藏羌塘北部的花岗岩带内,岩石K2O Na2O含量达11.27%～12.02%,具高铝、高碱、低铁镁组分的特征,属碱性花岗岩类.地球化学特征表明,该碱性岩形成于后碰撞期.形成该岩体的物质主要来源于加厚陆壳的中下部,反映了研究区古特提斯闭合后经历了陆内造山阶段.霞石正长岩同位素锆石U-Pb年龄为248.7Ma±2.6Ma,相当于早三叠世晚期.碱性花岗岩的出现是西藏西北部古特提斯造山带崩塌开始的岩石学标志.     

Modeling the sediment yield from landslides in the Shihmen Reservoir watershed,Taiwan

Landslides generate enormous volumes of sediment in mountainous watersheds; however, quantifying the downstream transport of landslide‐derived sediment remains a challenge. Landslide erosion and sediment delivery to the Shihmen Reservoir watershed in Taiwan was estimated using empirical landslide frequency–area and volume–area relationships, empirical landslide runout models, and the Hydrological Simulation Program‐ FORTRAN (HSPF). Landslide erosion rates ranged from 0.4 mm yr^‐1 to 2.2 mm yr^‐1 during the period 1986–2003, but increased to 7.9 mm yr^‐1 following Typhoon Aere in 2004. The percentage of landslide sediment delivered to streams decreased from 78% during the period 1986–1997 to 55% in 2004. Although the delivery ratio was lower, the volume of landslide sediment delivered to streams was 2.81 × 10⁶ Mg yr^‐1 in 1986–1997 and 8.60 × 10⁶ Mg yr^‐1 in 2004. Model simulations indicate that only a small proportion of the landslide material was delivered downstream. An average of 13% of the landslide material delivered to rivers was moved downstream during the period 1986–1997. In 2004, the period including Typhoon Aere, the annual fluvial sediment yield accounted for approximately 23% of the landslide material delivered to streams. In general, the transfer of sediment in the fluvial system in the Shihmen Reservoir watershed is dominantly transport limited. The imbalance between sediment supply and transport capacity has resulted in a considerable quantity of landslide material remaining in the upper‐stream regions of the watershed. Copyright © 2012 John Wiley & Sons, Ltd.     

A three-dimensional ocean general circulation model for mesoscale eddies——Ⅱ Diagnostic analysis

A three-dimensional density field associated with mesoscaie unstable waves generated by the 3-D, primitive-equation model (Wang and Ikeda, 1996) is provided to the quasi-geostrophic pressure tendency and ω-equations, and to the (ageostrophic) Q-vector equation. Diagnostic analyses, analogous to the approaches in meteorology: ω-equation and Q-vector method, are for the first time developed to examine the mesoscaie dynamical processes and mechanisms of the unstable waves propagating in the mid-latitude ocean. The weaknesses and strengths of these two diagnostic approaches are evaluated and compared to the model results. The Q-vector method is then recommended to diagnose the vertical motion associated with the mesoscaie dynamics from a hydrographic CTD (conductivity-temperature-depth) array, while the quasi-geostrophic equations produce some small-scale features (errors) in the diagnosed fields.     

A type of new conserved quantity deduced from Mei symmetry for Appell equations in a holonomic system with unilateral constraints

A type of new conserved quantity deduced from Mei symmetry of Appell equations for a holonomic system with unilateral constraints is investigated. The expressions of new structural equation and new conserved quantity deduced from Mei symmetry of Appell equations for a holonomic system with unilateral constraints expressed by Appell functions are obtained. An example is given to illustrate the application of the results.     

华北地区石炭－二叠系煤系地层和轻质油关系研究

对华北地区石炭－二叠系、下第三系、中上元古界沉积物和油样的低环萜烷参数用因子分析方法进行油源对比，表明石炭－二叠系部分样品与该区轻质油的关系密切。进一步分析这套地层的有机地球化学特征后，提出壳质组含量和成熟度是决定石炭－二叠系能否生成轻质油的主要因素，并提出该区煤系地层生成轻质油的成熟度下限是镜质组反射率Ｒ０为１．１％。     

采用基础摩擦隔震房屋高宽比限值的研究

大量的试验结果和地震经验表明，采用基础隔震方法能有效地提高建筑物的抗震能力，但建筑物的高度在什么范围，即建筑物的高宽比在什么范围内才适合采用这种方法，仍然是一个有待解决的课题。本文对采用基础滑移隔震多层砌体房屋在实际地震作用下的抗倾覆高宽比限值进行了研究，利用Ｗｉｌｓｏｎ－θ数值积分方法计算，得到了多层砌体房屋的高宽比限值的统计值。其数值结果可供编制建筑隔震设计规程参考。     

南海西沙海槽盆地重磁资料综合研究

本文综合利用广州海洋地质调查局历年来在中国南海西沙海域采集的重、磁、震资料,结合前人研究成果.采用了场源边缘识别、磁性体顶面埋深欧拉反演以及重、磁、震剖面联合反演等技术.针对西沙海槽盆地岩浆岩分布、重大断裂、深部构造等进行了综合研究.研究结果表明,盆地内岩浆岩主要形成于印支期和燕山期,大部分分布于盆地断阶带上;识剐出了NE向和EW向两组断裂.二者分别从北部和中部横贯盆地;盆地磁性基底埋深在6.0~12.6km之间。整体上呈"中部深、南北浅"的特征;西沙海槽盆地的莫霍面埋深在19~26 km之间,呈现出"南北深中部浅"的拉张裂谷特征.本文研究获取了西沙海槽盆地的基础地质构造特征.可深化盆地地质构造背景的认识,为该盆地下一步的油气工作提供基础研究资料.     

台湾浅滩西部水域海洋动物的石油烃含量和荧光光谱特征

本文报道了台湾浅滩西部水域鱼类、虾类和软体头足类动物的总石油烃含量,分析了主3类动物样品的荧光光谱特征,并将本文数据与南海其他水域海洋动物的石油烃含量作了比较。     

基于数字高程模型（DEM）的溧阳天目湖地区地貌区划

江苏溧阳天目湖地区地貌单元的划分可以提升分区、分类型、分层次的地表基质调查效率。基于天目湖地区5 m分辨率的数字高程模型（DEM）,应用GIS软件提取高程、坡度、地形起伏度信息;在提取地形起伏度的过程中运用邻域分析法与均值变点法,确定提取地形起伏度的最佳分析窗口大小为37×37像元。将地形起伏度、海拔高程及坡度3种地形要素进行空间叠加分析,并对地貌分布格局与差异变化进行初步探讨,提出将天目湖地区地貌指标划分为平原、河流阶地、山间谷地、台地、丘陵5种类型,其中以山间谷地与台地地貌为主,二者分别占32.97%、21.96%。划分结果符合天目湖地区地貌格局差异及空间分布,有效体现出天目湖地区平原向丘陵过渡的地貌特征,为后续开展地表基质的调查工作提供较为可靠的地理依据,对探究地貌分布格局与地表基质属性差异具有一定的意义。     

中国中央造山带内两个超高压变质带关系

中国中央造山带内至少发育两个超高压变质带,一个是南阿尔金-柴北缘-北秦岭超高压变质带,超高压峰期变质年龄为早古生代(500～400 Ma),代表扬子与中朝克拉通间的深俯冲和碰撞带;另一个是研究程度较高的大别-苏鲁超高压和高压变质带,峰期变质年龄主体是三叠纪(250～220 Ma),代表扬子克拉通内部的陆内大陆深俯冲和碰撞带。对东秦岭看丰沟及香坊沟的变质岩片详细岩石学和构造学研究以及先期造山带尺度的构造、岩石和年代学研究资料分析证明,南阿尔金-柴北缘-北秦岭超高压变质带,向东不能与大别-苏鲁超高压和高压变质带的任一部分相连,包括南大别和西北大别超高压及高压变质岩石。相反,大别-苏鲁超高压及高压变质带,向西经桐柏山,横过南襄盆地延伸到南秦岭的西峡及商南一带。仅在东秦岭-大别山范围内,两个超高压变质带分别位于南丹断裂系南北两侧,沿造山带近平行延展,之间被一系列以断裂或剪切带为边界的岩石构造岩片相隔,不能构成横贯中国中部统一的巨型超高压变质带。任何有关中国中央造山带构造格架及构造演化模型的建立,均应考虑其内部发育两个时代和功能不同的超高压变质带。