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Geochronological Sequence of Mesozoic Intrusive Magmatism in Jiaodong Peninsula and Its Tectonic Constraints

ZHANG Tian and ZHANG Yue-qiao   

  1. Department of Earth Sciences, Nanjing University, Nanjing 210093, China
  • Received:2007-06-20 Revised:2007-06-20 Online:2007-06-20 Published:2007-06-20

Abstract: Jiaodong Peninsula,located in the North China Craton east of the Tanlu fault zone,is one of the most important areas of Mesozoic intrusive rocks population.A geochronological sequence of Mesozoic intrusive rocks has been established through a detailed study of high-resolution isotopic ages of intrusive plutons in this area. Three periods with different magmatisms are distinctive:the Late Triassic mantle-derived granites aged 225~205 Ma, the Late Jurassic crustal-derived S-type granites aged 160~150 Ma, and the Early Cretaceous crust-mantle mixed sourced granites aged 130~105 Ma.A comparison of geochronological framework of the Mesozoic intrusive rocks with those outcropped in Liaodong and Luxi-Xuhuai areas provides key information to constrain tectonic evolution of North China.It points out that the Late Jurassic crustal-derived S-type granites in Jiao-Liao area record an important crustal thickening event, which is considered to be geodynamically related to flat subduction of the Pacific plate beneath the Asia continent. This was followed by lithospheric delamination and attenuation during the Early Cretaceous, which resulted in widespread crust-mantle mixed sourced granitoid magmatism in East China. Crustal thickening and thinning are considered to be main cause for changes in Mesozoic tectonic regime and sequential evolution of magmatism in East China.