韧性剪切带与金矿化的关系——以冀东金厂峪金矿床为例

以金厂峪金矿床为例,研究了韧性剪切带的特征、形成环境、演化发育过程及其与金矿化的关系。韧性剪切带发育过程中的应力周期是含金流体定向迁移的驱动力,与其伴生的退变质作用则为金的活化、迁移及富集沉淀提供了必须的化学条件。韧性剪切带的发育不仅为含金流体的运移提供了通道,而且为金的富集沉淀提供了场所。     

方解石脉在断层新活动研究中的应用

本文以发育在断层带内的方解石脉为主要研究对象,运用野外调查、显微镜下观测、同位素测年法相结合,对许多重大工程区的断层活动进行了研究,确定了南盘江天生桥一级水电站场址区F_8断层最后一次强烈活动时间为200ka B。P。左右,150ka以来断层无活动:河北省阳原县石匣里水库坝区五条主要断层最后一次强烈活动时间为200—300ka B。P。,200ka为断层活动的时间上限。     

Application of Calcite Veins to Study of Newly-activated Faulting

The study of period and chronology of fault activity in major worksites in an area with exposed basement rocks is quite difficult. The authors have applied the combinative techniques of field investigation, microscopic observation and isotopic dating to studying the calcite veins filled in the fault zones in several major engineering regions and got successful results. The following conclusions are reached: (i) The last period of strong activity of fault F8 in the Tianshengqiao Hydropower Station, Nanpan River is 200 ka B. P. , and there has been, no obvious activity since 150 ka. (ii) The last period of strong activity for 5 faults in Shixiali Reservoir, Yangyuan County, Hebei Province is 200-300 ka B. P. , and there has been no obvious activity since 200 ka. The research results provide a sound basis of engineering geology for project designers.     

我国东部若干二辉橄榄岩团块的流动构造及流动应力估计

对我国东部若干新生代玄武岩中二辉橄榄岩团块的流动构造研究表明,这类团块所经受的高温变形条件下的塑性流动,主要是通过位错攀移和滑动机制来完成的. 根据具有残碎斑晶结构的团块中橄榄石新变晶的粒度、亚晶粒的粒度、自由位错密度以及位错段的曲率估算了流动应力的大小.不同地点的样品流动应力值的差异表明,新生代时期我国华北、东北地区上地幔流动应力值高于华东地区;靠近郯庐断裂带的上地幔流动应力值高于远离断裂带的,这反映了新生代时期我国东部地区构造活动的强度和特征的差异性.