吉林深源地震群地质构造背景与动力分析

吉林深震群位于中国东北大陆板缘古生代地槽褶皱系内,上叠有中新生代断陷裂谷盆地。区内广泛喷溢了βN_2—βQ_4玄武岩浆,深震震中大多位于火山口、火山锥玄武岩内附近。从岩浆幔漂包体、岩浆岩化、岩浆携带的上地幔岩石组合出现顺序的综合判断,上地幔可分出Ⅷ层序以及推断的深震源Ⅸ层序列,据平剖面分析深震与玄武岩浆共生活动。日本海沟—我国深震区中深源地震震源机制解表明P轴呈连续地插入我国东北上地幔深度590km层内并持续活动,深震发生的动力来自西太平洋岩石圈板块俯冲消减运动本身的挤压应力活动。     

海南岛第四纪玄武岩风化壳中次生矿物转变与时间的关系

本文采用X射线分析法,从分析风化壳中的次生矿物入手,研究了海南岛北部不同地质年龄的第四纪玄武岩风化壳中次生矿物增长数量与风化时间的关系。两者关系的回归方程为Y=4.1898 207.30t,其中Y为次生矿物的含量(g/cm~2),t为风化时间(Ma)。相关系数γ=0.9977。每0.01Ma次生矿物平均增长2.2164g/cm~2。     

An Experimental Melting—crystallization Study on Basalt at High Pressures

A series of melting-crystallization experiments on alkali basalt samples from Minqing, Fujian Province was carried out in dry and waterbearing systems at high pressures. A high-pressure melting curve was obtained. The results indicate that clinopyroxene crystallized from basalt melt at 13.5–23.7 kbar. spinel at 23.7–28.6 kbar and garnet at > 28.6 kbar. With increasing pressure, the CaSiO₃ contents of clinopyroxenes increase; and the FeSiO₃ decreases, but the chemical composition of garnet does not show any significant difference. The minerals are larger and euhedral in the water-bearing system. Therefore, we consider that natural megacrysts of the basalt can crystallize from the water-bearing basalt magma at high pressure. So the megacrysts may be derived from the upper mantle as a result of magmatic crystallization-fractionation under high pressure. This project was financially supported by the National Natural Science Foundation of China.     

468-A型连杆绞链式基桩扩底钻头

扩大钻孔灌注桩桩底底面积是提高基桩单桩承载能力,降低工程造价的有效方法.468-A型连杆绞链式基桩扩底钻头(以下简称扩底钻头)是湖南省地矿局468队自行设计研制的用于基桩孔扩底施工的特型     

黔西南表层脱底褶皱及对金矿床的控制作用

在研究黔西南表层脱底褶皱地表地质特征和其形成机制的基础上,认为黔西南微细粒浸染型金矿床是成岩期后构造作用下的产物,受控于表层脱底褶皱,并提出了金矿远景区和找矿方向。