Rb Sr ISOCHRON AGE GROUPS OF ROCKS FROM THE EASTERN SECTOR OF NORTHERN HUAIYANG AND THEIR REGIONAL GEOLOGICAL SIGNIFICANCE

Four whole rock Rb Sr isochron age groups of the rocks from the eastern sector of northern Huaiyang indicate that metamorphic rocks exposed at Liqiao,Jinzhai county,and Fanghushan,Feixi county,are middle Proterozoic in age （1595-1726Ma）,while metamorphosed supracrustal rocks on the northeastern margin of the Dabie Mountains are marked by the component rocks of the Foziling Group of late Proterozoic age （759-822Ma）.