胶东崮庄闪长岩锆石U-Pb年代学和岩石地球化学研究

Study on Zircon U-Pb Chronology and Rock Geochemistry of Guzhuang Diorite in Jiaodong Area

对胶东崮庄岩体黑云母闪长岩进行了岩石学、岩石地球化学和年代学研究。研究表明:崮庄岩体黑云母闪长岩为钙碱性系列岩石,岩石富集大离子亲石元素(如K,Ba,Rb)、LREE和活泼的不相容元素(如Th,U),相对亏损高场强元素(如Nb,Ta,Ti,P),崮庄闪长岩属壳幔混合成因,即由交代地幔部分熔融形成的基性岩浆与地壳物质熔融形成的酸性岩浆混合形成的。构造环境判别显示崮庄闪长岩属火山弧花岗岩,暗示伟德山序列花岗岩与古太平洋板块向欧亚板块俯冲密切相关。崮庄闪长岩LA-ICP-MS锆石U-Pb年龄值为(111.7±0.6)Ma,属燕山期早白垩世。

The petrology,geochemistry and geochronology of Guzhuang diorite have been studied in this paper.It is showed that diorite is a series of calc alkaline rocks,which are enriched in LILE(such as K,Ba,Rb),LREE and more mobile incompatible elements(such as Th,U),relatively depleting in HFSE(such as Nb,Ta,Ti,P).Guzhuang diorite belongs to mixed formation of crust and mantle.It is formed by the mixture of basic magma formed by partial melting of metasomatic mantle and the mixture of acid magma formed by the melting of crustal materials.Tectonic discrimination shows that Guzhuang diorite belongs to volcanic arc granite.It is suggested Weideshan granite series and Paleo Pacific plate to the Eurasian plate is closely related.LA ICP MS zircon U[CD*2]Pb dating is(111.7±0.6)Ma,which belongs to early Cretaceous.in Yanshanian period.