POSSIBLE EXISTENCE OF THE PRE-ARCHEAN CONTINENTAL CRUST IN SHANGZHUANGZI,QIAN’AN COUNTY,HEBEI

The Bi content in certain rocks may probably have age significance,i.e. the lower the Bicontent,the older the rocks will be.For example,in Shanghuangzi,Qian’an,there is an areawith the lowest Bi content.This area shows a peculiar geochemical features,that is,there areregional geochemical positive anomalies of not only ultrabasic elements but also basic, acid andeven alkaline elements in a not big areal extent.They are mostly large- ion lithophile refracto-ry elements. To there might exist a pre- Archean terrane in the area, This inference is also ev-idenced by field geological data.