壳幔化学不均一性与块体地球化学边界研究

壳幔派生岩石的多元同位素体系研究表明,地球存在块体的化学不均一性,可划分出地球化学省,并以地球化学急变带作为边界。全球总体上分成东冈瓦纳（如华夏与青藏—印支）、西冈瓦纳、太平洋（如佳木斯、中蒙古、辽胶渤、北疆—南戈壁）与劳亚（如华北、中朝、兴安、塔里木等）四种类型的地球化学省。地球化学急变带与地球物理场变化存在密切关系。在构造上,地球化学急变带可分成构造显性与构造隐性两种类型。应用深、浅构造立交模型及其相互转化可对两种类型地球化学急变带的出现作出较合理的解释。地球化学急变带,特别是急变带的转折端对超大型矿床和成矿密集区的分布有密切控制作用;显性急变带主要表现为与动力变质和岩浆活动有关的改造成矿作用,隐性急变带主要表现为火山与热水沉积成矿作用。具有工业意义的油气田均位于构造隐性急变带与中新生代盆地的立交地段。     

研究地壳中流体的工作方法

地壳中广泛存在流体,它在地壳的演化过程中起着重要作用。目前对于地壳中流体的研究主要重于其来源、时代、成分、热和质量的传递以及流体和矿物、岩石的相互作用。文中叙述了研究地壳中流体有关内容所采用的各种工作方法,包括了流体的同位素及年代学研究方法,重点介绍了近年运用人造卫星和遥感技术研究地壳中流体的新方法。最后用实例阐明了当前研究地壳中流体的成就。     

镁质粘土在碱性耐火材料工业应用的初步探索

本研究项目的主要步骤是把镁质粘土和橄榄岩或焦油镁砂砖废料在箱式电炉里进行烧结试验（温度１２００～１２５０℃）。同时测定了原料、烧结样品和５种产品的物理性质和矿物组分。结果表明,产品里的矿物多是富镁的高熔点矿物,包括继承性的或新生的镁橄榄石和方镁石,少量钙镁橄榄石、镁黄长石以及痕量硅酸二钙。２号产品含较多的斜顽辉石,由滑石或海泡石转化而成,它的熔点较低。试验表明,妥善选择原料和配方是走向成功的第一步,而瘠性和塑性材料相配合,则是传统经验的重现。在这种场合,镁质粘土作为结合粘土,起了很大作用。利用氧气煤气火焰快速测定熔点也是有意义的尝试。     

A Preliminary Study on the Preparation of Four Pacific Ocean Polymetallic Nodule and Sediment Reference Materials: GSPN-2, GSPN-3, GSMS-2 and GSMS-3

The research project for the preparation of two polymetallic nodule (GSPN-2, GSPN-3) and two marine sediment (GSMS-2, GSMS-3) reference materials was completed in 1996. The samples were collected from the Eastern and Central Pacific Ocean and prepared to less than 74 μm fine powder. The homogeneity of the materials was tested by X-ray fluorescence spectrometry. The relative standard deviations (RSD %) of measurements of selected elements in samples taken from thirty bottles selected at random were less than 0.5%. Thirty four laboratories worldwide participated in the collaborative analysis programme. The number of elements or constituents analysed was seventy nine for nodules and eighty one for sediments. Among those, sixty three elements were certified in each sample. The sum of major elements or components is 99.7% for GSPN-2, 99.5% for GSPN-3, 99.8% for GSMS-2 and 99.8% for GSMS-3.     

垂直形变测量与地应变

讨论地壳垂直形变与地应变的关系。根据水准测量或地倾斜观测,定义了平均地倾斜与地倾斜率;根据应变与位移的关系,推导任一坐标方位角方向的地倾斜或地倾斜率与应变或应变率分量的关系。根据分析,初步得出结论：在１个水准点上,如果有与不同方向的８个水准点之间的高差以及距离的观测值,且这８个水准点不在同一平面内,则理论上可唯一地确定６个应变分量;在某一区域,如果有若干个不在同一平面内的水准点,由它们可求得８个以上不同方向的地倾斜,并可按最小二乘法求得该区域的６个平均地应变分量。     

高喜马拉雅中段近期的地壳运动——大地测量最新结果及其解释

基于１９９２、１９９６年两期ＧＰＳ重复观测资料,对喜马拉雅中段的地壳运动及其机制作了初步分析和探讨。结果表明：江孜（喜马拉雅）块体在喜马拉雅南侧和雅鲁藏布江北侧的水平挤压下,以１２ｍｍ／ａ缩短,这与Ｍｏｌｎｅｒ等所给出的５０～６０ｍｍ／ａ相比要小得多;喜马拉雅的垂直运动（隆起）速率各点平均值仅为５．３ｍｍ／ａ。最后,对喜马拉雅和青藏高原隆起的机理作了初步探讨。     

A wide-angle seismic traverse through the Variscan of southwest Ireland

A wide-angle seismic profile across the western peninsulas of SW Ireland was performed. This region corresponds to the northernmost Variscan thrust and fold deformation. The dense set of 13 shots and 109 stations along the 120  km long profile provides a detailed velocity model of the crust.
  The seismic velocity model, obtained by forward and inverse modelling, defines a five-layer crust. A sedimentary layer, 5–8  km thick, is underlain by an upper-crustal layer of variable thickness, with a base generally at a depth of 10–12  km. Two mid-crustal layers are defined, and a lower-crustal layer below 22  km. The Moho lies at a depth of 30–32  km. A low-velocity zone, which coincides with a well-defined gravity low, is observed in the central part of the region and is modelled as a Caledonian granite which intruded upper-crustal basement. The granite may have acted as a buffer to northward-directed Variscan thrusting. The Dingle–Dungarvan Line (DDL) marks a major change in sedimentary and crustal velocity and structure. It lies immediately to the north of the velocity and gravity low, and shows thickness and velocity differences in many of the underlying crustal layers and even in the Moho. This suggests a deep, pre-Variscan control of the structural development of this area. The model is compatible with thin-skinned tectonics, which terminated at the DDL and which incorporated thrusts involving the sedimentary and upper-crustal layers.