Extrinsic and intrinsic mode of hydrogen occurrence in natural olivines: FTIR and TEM investigation

Olivine crystals from two mantle nodules in kimberlites (pipe Udachnaya and pipe Obnazennaya, Yakutiya, Siberia) were investigated using EMP, TEM, AEM and FTIR techniques to determine the mode of hydrogen occurrence in olivine. Olivine contains three types of nanometer-sized inclusions: “large” inclusions of hexagonal-like shape up to several hundred nm in size (1), lamellar defects (2) and small inclusions of hexagon-like shape up to several 10?nm in size (3). Lamellar defects and small inclusions are considered to be a “hydrous” olivine. All three types of inclusions contain OH^? or water, but they are different with respect to their phase composition. In “large” inclusions (1) hydrous magnesium silicates, such as serpentine?+?talc (“kerolite”?) and 10-Å phase?+?talc were identified. Lamellar defects (2) and small inclusions (3) are depleted in Mg and Fe compared to the olivine matrix, while the silica content is the same as that of olivine. Modulations in the periodicity of the olivine structure are observed in SAED patterns and HREM images of (2) and (3). The superperiodicity can be referred to OH^?-bearing point defect ordering in the olivine structure. If this is the case, the material of both lamellar defects and small inclusions can be assumed to be a “hydrous olivine” Mg_{2– x} v _x SiO₄H_{2 x} with a cation-deficient olivine crystal structure. Thus, both an extrinsic mode of hydrogen occurrence in olivine, such as nanometer-sized inclusions of OH^?-bearing magnesium silicates, and an intrinsic mode of hydrogen incorporation into the olivine structure, such as “hydrous olivine” in itself, were found. The data obtained here show that the OH absorption bands observed in olivine spectra at 3704(3717) and 3683(3688) cm^?1 can be unambiguously identified with serpentine; the band at 3677(3676) cm^?1 can be associated with talc. The absorption bands observed at 3591 and 3660?cm^?1 in olivine match those of the 10-Å phase at 3594, 3662 and 3666?cm^?1.     

北祁连造山带西段前造山期伸展构造特征——以肃北县鱼儿红地区为例

北祁连山是著名的加里东期造山带 ,以往地质研究主要集中在建造和主造山期板块俯冲 -碰撞及陆内造山构造方面。作者通过在北祁连山西段区调填图 ,发现了一套基本顺层发育的拆离滑脱正断层、顺层韧性剪切带、流劈理及掩卧褶皱等 ,笔者对其构造样式、组合关系、运动学、动力学特征和相关建造的发育等进行了阐述、分析与讨论 ,认为它们是与前造山期裂谷盆地建造发育密切相关的同构造正断层型伸展构造群落。     

南极乔治王岛菲尔德斯半岛湖泊堆积物的物相组成特征及其环境意义

本文根据南极乔治王岛菲尔德斯半岛燕鸥湖、西湖和基太克湖三个堆积剖面物相组成与丰度的资料，讨论其物相组成特征、物质来源及其环境意义。研究结果表明，湖泊堆积物主要来自该岛广泛分布的火山岩。在南极地区干冷环境条件下，源区母岩所经受的风化作用以物理风化为主，化学风化微弱。高岭石、方解石丰度与年龄关系曲线在湖积层与冰碛层之间的陡削变化表明，相应的环境变化是突变式的，可能与这两种堆积物搬运方式的不同和冰碛物的保护作用有关。     

西北地区城市规模分形结构的研究

本文利用分形理论和相空间概念，从理论的角度演绎推导出城市规模分形结构的一般模式，并以此为基础，结合西北地区自然，经济，社会状况，对五省萄城市规模分形结构进行初步分析，为深入研究其城市体系，制定城市，区域发展战略提供一定的参考。     

用S_p震相测定甘肃局部地区地壳厚度

根据安西、高台、兰州、天水地震台记录到的 S_p 震相资料测定了4个台附近局部地区的地壳厚度值。得出了在安西周围25—72km 环形区域内的平均地壳厚度值为58.8±2.1km;高台台周围25—68km 环形区域内的平均地壳厚度值为56.0±1.7km;兰州台周围25—50km 环形区域内的平均地壳厚度值为53.9±1.6km;天水台周围23—45km 环形区域内的平均厚度值为51±2.7km。甘肃地区地壳厚度的结果是西厚东薄,东西平均地壳厚度差达7.8km 左右。     

太阳耀斑期间电离层效应的观测分析

一、一般情况 1989年7月31日到9月9目,在新乡、临潼和乌鲁木齐三点对VLF Omega信号相位变化进行了同时接收。与此同时,乌鲁木齐天文站的太阳色球观测和乌鲁木齐电离层垂测站的电离层探测也同时进行。在这期间,三个VLF信号观测点上同时有记录的太阳活动事件有36次。其中最大的发生在8月15日、16日和17日。特别是8月16日的太阳耀斑造成电离层垂测站的频高图近四个小时内没有回波。     

四川省地震重点监视防御区未来地震潜势的研究

本文通过历史地震及现今地震活动性的分析、活断层分段理论及地震空区理论的应用、地震平均复发间隔及复发条件概率的估算以及多学科专家综合评估方法的引入，对川西鲜水河－安宁河－则木河断裂和滇东小江断裂带（中－北段）上15个不同段落的地震潜势进行了深入的研究。进一步修正并重新圈绘出位于鲜水河－安宁河－则木河断裂带上的四川省地震重点监视防御区，其范围：北起道孚县的葛卡或者松林口一带，南至西昌市，沿鲜水河－安宁河－则木河主干断裂带展布，全长约350千米。按对未来地震震级估计的不同，该区可分成3段。第1段位于葛卡或松林口至康定之间，震级估计为7±1／4级；第2段位于康定与石棉之间，估计的震级是61／2±1／4；第3段位于石棉至西昌之间，震级估计为7－71／2。此外，研究结果还显示了小江断裂带上的新塘湾和寻甸一嵩明两个段落未来15年内强震发生的概率相对较高。     

Temporal and spacial analysis of regional composite nodal plane solutions for small earthquakes

A method is proposed in this paper for the analysis of temporal and spatial characteristics of composite nodal plane solutions for small earthquakes. With this method, the interested region is devided into small areas according to the geological features of the region. As an example, 107 composite nodal plane solutions are calculated for the adjoining region of Shaxi, Hebei and Neimenggu. The temporal and spatial characteristics of the variations of the solution parameters before and after the great Tangshan main earthquake in 1976 have been analysed and some interesting results are obtained. The Chinese version of this paper appeared in the Chinese edition ofActa Seismlogica Sinica,13, 9–20, 1991.     

各向异性介质相速度、群速度与克利斯托费尔方程

本文详细回顾了克利斯托费尔方程(Christoffel)的推导.在此基础上,提炼出时空域和频率域克利斯托费尔方程,前者可作正演计算介质的相速度,后者可计算介质的群速度.并计算了横观各向同性介质的相速度和群速度.最后对无损耗各向异性介质的相速度和群速度的关系进行了简单讨论.