摘要
The Yinshan Block is a coherent Neoarchean basement of the Western Block in the North China Craton.The representative is at Guyang area,which composed of granite-greenstone rocks at western and high-grade metamorphic complexes at eastern.The result of statistics of zircon U-Pb age statistics show either the granite-greenstone or the protoliths of the high-grade metamorphic complexes formed at the late Neoarchean (2562 ~ 2510Ma),and experienced two stage metamorphic event at ~ 2500Ma,~ 2480Ma respectively.The P-T path of the ~ 2.50Ga metamorphism is an anti-clockwise type,which is related with the mid-oceanic ridge subduction.There are a variety of special rocks which indicating the certain tectonic background in this area,such as:komatiite,komatiitic basalt,Nb-rich basalt,high-Mg andesite,TTGs and Sanukitoid.In conclusion,the Yinshan block is controlled by the plate tectonics,and experienced the mid-oceanic ridge subducted and collision orogeny successively.The BIFs in this are related with the mid-oceanic ridge subduction.The Si and Fe of BIFs are derived from the basalt at the bottom of greenstone belt and the komatiite,respectively.