Abstract:Monzonitic-orthoclase granites in Sihaishan area have the structure evolution from fine grain to coarse grain, and component evolution from acid to meta-acid and rich-alkaline, as well as include typical accesory mineral ilmenite which specially occurred in S-type granites. As showed by the chemical components, the granites are rich in silicium and aluminium, and their rare earth pattern model belongs to crust-remelting type, while the compond diagnostic diagram shows them as intrusives formed in the late o...