吉林省东部新生代火山岩系中的杏仁体与热水成矿作用

吉林省东部山区大面积出露新生代火山岩,但多年以来地质科技人员很少在新生代火山岩中找矿。作者收集了近几年的有关资料,分析了杏仁体的主要特征、杏仁体形态特点、杏仁体的内部构造、杏仁体的矿物组成及其与热水成矿作用关系。供同仁们在火山岩找矿方面参考。     

青海南部治多县扎河一带上三叠统巴塘群火山岩特征及其构造环境

巴塘群火山岩主要由基性玄武岩-中性安山岩-流纹岩组成,构成一套从基性到中性到酸性的岩石组合,具较完全的演化序列。岩石化学表现为表现为低Ti O2(1%),高Al;稀土元素特征表现为轻稀土元素富集;在微量元素地球化学方面,表现为富集大离子亲石元素,亏损高场强元素,εNd(t)变化在-0.3~2.9之间,εSr(t)变化在14.4~39.2之间,表现为弧火山岩特征,为拉竹龙-金沙江洋盆(或甘孜—理塘洋)向南消减的产物。     

Geochemical Characteristics of Apatite in Heavy REE‐rich Deep‐Sea Mud from Minami‐Torishima Area,Southeastern Japan

We have conducted geochemical and mineralogical investigations of the rare earth and yttrium (REY)‐rich mud from the Minami‐Torishima area in the Pacific in order to clarify the concentration of REY and their host‐phase in the mud. X‐ray diffraction analysis shows that the mud is mainly composed of phillipsite, fluorapatite, quartz, albite, illite and montmorillonite. Whole‐rock CaO, P₂O₅ and total REY contents of the mud are positively correlated. Relative abundance of apatite is also positively correlated to P₂O₅ and total REY contents. These correlations suggest that apatite is the main host of the P₂O₅ and REY in the mud. We make in situ compositional analyses of constituent minerals in the REY mud. The results show that the apatite is abundant in REY (9300–32,000 ppm) and is characterized by a negative Ce anomaly and enrichment in heavy rare‐earth elements. This abundance and composition of REY of the mud is similar those of fish debris apatites. In contrast, phillipsite is less abundant in REY (60–170 ppm). Therefore we conclude that the main REY host phase of the mud is apatite.     

长白山天池火山灾害预警基础数据库的初步建立

本文主要介绍了建立长白山天池火山灾害预警基础数据库的必要性及运用Mapinfo软件为平台建立的基础数据库的结构及功能。     

金平防浪堤爆破挤淤工程对附近水域及岸上建筑物的影响分析

根据工程的地域特点和工程的施工要求，分析了爆破挤淤技术的原理、参数的选择和可能造成的影响，提出了减小影响的措施，论证了合理地选择爆破参数、采用爆破挤淤技术的可行性。施工实践证明用爆破挤淤技术建设防浪堤是成功的。     

UPWELLING AND SEDIMENTATION DYNAMICS Ⅲ：COINCIDENCE OF UPWELLING AREAS WITH MUD PATCHES IN NORTH HEMISPHERE SHELF SEAS

The determinant role of upwelling in fine sediment patches is examined from the view-points of physical process and biological process respectively. It is pointed out that physical and biologicalprocesses are usually coexistent and interact with each other during the sedimentation of suspended mat-ters. This study used available figures showing the circulation pattern and surface sediment distribution inthe whole China Seas, the Gulf of Maine, the Irish Sea and the North Sea, and additional data to verifythat wherever upwelling exists on the continental shelf, mud must occur; and that wherever dowrtwellingoccurs, coarse sediment substitutes for mud.     

Controls on effective settling velocities of mud flocs in the Changjiang Estuary,China

Theoretical and experimental studies were undertaken to gain insight into physical parameters controlling the flocculation and settling properties of mud flocs in the Changjiang Estuary, China. The Rouse equation is applied to vertical profiles of suspended sediment concentration to determine the bulk mean settling velocity (w_s) of sediment suspended in the Changjiang Estuary. Both in situ point‐sampled and acoustically measured profiles of suspended mud concentrations were fit selectively. The calculated settling velocities w_s mainly ranged from 0·4 to 4·1 mm s^?1 for the point‐sampled data set, and from 1·0 to 3·0 mm s^?1 for the acoustically measured data set. Furthermore, the settling velocities of mud flocs increased with mean concentration (C?) of mud flocs in suspension and were proportional to increasing bottom shear stress (τ_b) of tidal flow. The best equation for the field settling velocity of mud flocs in the Changjiang Estuary can be expressed by the power law: w_s = mC?ⁿ (m, 1·14–2·37; n, 0·84–1·03). It is suggested that C? and τ_b were the dominant physical parameters controlling the flocculation and w_s of mud flocs in suspension. Copyright © 2004 John Wiley & Sons, Ltd.     

特殊性岩土膏溶角砾岩的工程特性研究

膏溶角砾岩,是含膏盐岩系中的易溶硫酸盐岩溶蚀后的角砾岩,也是工程勘察中新发现的特殊性岩土的一种新类型。对膏溶角砾岩的地质背景、成因、工程地质特征进行了系统论证。     

鉴江下游及其支流小东江和袂花江放射性研究

为了解鉴江放射性含量，分别在鉴江流域布设了5个水质和底泥监测点，取样进行总α和总β分析，并与省内本底调查资料比较，结果表明：鉴江水质中放射性含量上下游都比较低，而底泥的放射性含量则下游略高于上游；鉴江底泥放射性含量也低于省内各地土壤放射性含量的平均值；鉴江水质放射性总α和总β符合生活饮用水卫生标准。