五台山东部吕梁期逆冲推覆构造

Late Palaeoproterozoic Thrust Nappe Structure in Eastern Wutaishan Mountain

五台山东部石咀—口泉一带,发育着一系列北东—南西向的韧—脆性逆冲推覆构造,将五台山花岗绿岩带分隔成叠瓦状的构造片体。断裂破碎带岩石在先存的五台期角闪岩相变质岩之上,叠加了绿片岩相动力退变质作用,普遍出现绿泥石、直闪石、绢云母、堇青石等新生的变质矿物。许多运动学指向标志指示上盘由北西向南东方向逆冲推覆,从而使滹沱群形成一系列北东向次级倒转向斜,并在大甘河以西与滹沱复向斜贯通。该逆冲推覆构造出现于吕梁运动的晚期,记录着五台山东部早前寒武纪结晶基底的最后一次构造热事件。

Around Shizui and Kouquan villages in eastern Wutashan Mountain, a series of developed ductile-brittle thrust nappe structures can be observed, by which the Archean Wutaishan granite-greenstone belt has been divided into some tectonic slices imbricated each other. The pre-exist amphibolite facies rocks in the fracture belt have been superimposed by retrograde green-schist facies with neoformation of chlorite, anthophyllite, sericite and cordierite. A lot of senses of structural displacement indicate that the thrust direction of the upper nappe side was from NW to SE, which made the Palaeoproterozoic Hutuo Group fold into a series of second order over synclines with strike-line of NE, and then penetrate in the Hutuo composite syncline zone to west of Daganhe River. This thrust nappe structure took place during the Late Palaeoproterozoic (Lüliang Movement), representing the last thermo-tectonic event in the Early Precambrian basement of Wutaishan Mt. 