SHRIMP Zircon U-Pb Dating of the Tongshi Magmatic Complex in Western Shandong and Its Geological Implications  

作　　者：HU Huabin MAO Jingwen LIU Dunyi NIU Shuyin WANG Yanbin LI Yongfeng SHI Ruruo 

机构地区：[1]Shijiazhuang University of Economics, Shijiazhuang, Hebei 050031 [2]China University of Geosciences, Beijing 100083 [3]Institute of Geology, Chinese Academy of Geological Science, Beijing 100037

出　　处：《Acta Geologica Sinica(English Edition)》2005年第4期491-496,共6页地质学报（英文版）

基　　金：This study was supported by the Major State Basic Rsearch Program of China(grant G1999043211);National Natural Science Foundation of China(grant 40272088).

摘　　要：The SHRIMP U-Pb zircon dating result of the Tongshi magmatic complex in western Shandong is presented in this paper. The Tongshi magmatic complex comprises fine-grained porphyritic diorite and syenitic porphyry. Eighteen analyses for fine-grained porphyritic diorite gave two concordia ages, in which ten analyses constitute the young age group, giving ^206Pb/^238U ages ranging from 167.9 Ma to 183 Ma with a weighted mean age of 175.7±3.8 Ma, and the other eight yielded ^207Pb/^206Pb ages of 2502 Ma to 2554 Ma with a weighted mean 2518±11 Ma. Two analyses for syenitic porphyry gave ages of 2485 Ma and 2512 Ma, respectively. The age of 175.7±3.8 Ma indicates that the crystallization of the Tongshi magmatic complex occurred in the Middle Jurassic, whereas that of 2518±11 Ma is interpreted as the age of inherited magmatic zircons in the Neoarchean Wutai period.The SHRIMP U-Pb zircon dating result of the Tongshi magmatic complex in western Shandong is presented in this paper. The Tongshi magmatic complex comprises fine-grained porphyritic diorite and syenitic porphyry. Eighteen analyses for fine-grained porphyritic diorite gave two concordia ages, in which ten analyses constitute the young age group, giving ^206Pb/^238U ages ranging from 167.9 Ma to 183 Ma with a weighted mean age of 175.7±3.8 Ma, and the other eight yielded ^207Pb/^206Pb ages of 2502 Ma to 2554 Ma with a weighted mean 2518±11 Ma. Two analyses for syenitic porphyry gave ages of 2485 Ma and 2512 Ma, respectively. The age of 175.7±3.8 Ma indicates that the crystallization of the Tongshi magmatic complex occurred in the Middle Jurassic, whereas that of 2518±11 Ma is interpreted as the age of inherited magmatic zircons in the Neoarchean Wutai period.

关 键 词：ZIRCON SHRIMP U-Pb dating age Middle Jurassic Tongshi magmatic complex western Shandong 

分 类 号：P588.1[天文地球—岩石学] P597.3[天文地球—地质学]