The lower basement consisted mainly of metamorphic intrusiverock, in ascending order: basic eruptive surficial crust rock,Yangzhaiyu grey gneiss,Sifangougneissic granite from early to late,the ages belong to Late Archaeozoic Era;

• 下基底以变质侵入岩为主体，按时序从早到晚为基性喷发表壳岩、杨砦峪灰色片麻岩、四范沟片麻状花岗岩，时代属晚太古代；