玲珑花岗岩中锆石的离子质谱U-Pb年龄及其岩石学意义

The Implication of the SHRIMP UPb Age in Zirconto the Petrogenesis of the Linglong Granite,East Shangdong Province

胶东招掖玲珑花岗岩锆石ＳＨＲＩＭＰＵ－Ｐｂ年龄结果表明，玲珑花岗岩形成于中生代燕山期（岩浆锆石年龄为１５０～１６０Ｍａ之间），岩体中产有大量的中生代印支期继承锆石（２００～２５０Ｍａ）及少数前寒武纪继承锆石。大量印支期锆石的存在说明玲珑花岗岩是壳源成因的，其源岩主要是中酸性岩石，推测可能是印支期华北华南两地块碰撞形成的造山花岗岩，这否定了长期以来人们普遍接受的玲珑花岗岩主是胶东群变质岩重熔或交代－重熔的认识。

The SHRIMP UPb ages in zircons of the Linglong Granite, East Shangdong Province, indicate that the Linglong Granite was emplaced at the early Yanshanian epoch, Mesozoic Era (the ages of the magmatic zircon population in the Linglong Granite range from 160 Ma to 150 Ma), and that a great number of inherited zircons with age of IndoChinese Epoch (250～200 Ma) and minor inherited zircons with age of Precambrian Era exist in the granite. This suggests that the Linglong granite is crustal origin, and that the immediate source rock for the granite is felsic to intermediate in composition. It is inferred that this source rock is likely the granitoid formed in the collisional event between the North China and the South China cratons. This does not support that the Longlong granite was formed by direct melting of the Archaean Jiaodong Group, as inferred by nearly all previous Chinese geologists.