1Introduction The well exposed Hengshan terrain of the North China Craton(NCC)is situated in northern Shanxi Province,about250km WSW of Beijing(Fig.1),and is one of the classical areas of Archaean to Palaeoproterozoic geology of China.It is separated from the Wutai Mts.by the broad valley of the Hutuo River and is made up of the Heng Mts.,extending in a broad NE-SW trending belt and bounded by the valleys of the Sanggan and Hutou Rivers(Fig.1).The Heng Mts.constitute a typical hig…