• Corpus ID: 131718470

Temporal-spatial variations,origin and their tectonic significance of the Late Mesozoic granites in the Qinling,Central China

@article{Xiao2011TemporalspatialVA,
  title={Temporal-spatial variations,origin and their tectonic significance of the Late Mesozoic granites in the Qinling,Central China},
  author={Wang Xiao and Mlr Key},
  journal={Acta Petrologica Sinica},
  year={2011}
}

• W. Xiao, Mlr Key
• Published 2011
• Geology
• Acta Petrologica Sinica

Zircon U-Pb dating for three large granitoid batholiths,geochemical and Hf isotope analyses for two of them have been carried out in the different blocks of the Qinling.Zircon dating by LA-ICPMS for the Lantian granitoid in the southern margin of the North China Block gives an age of 133±1Ma.The granitoids show whole-rock eNd(t)=-11.8~-18.3,zircon eHf(t)=-37.7~-5.7.The Muhuguan and the Mangling granitoids in the North Qinling orogen yield zircon LA-ICPMS and SHRIMP age of 150±1Ma and 149±2Ma,respectively.The Muhuguan granitoids show whole-rock eNd(t)=-7.6~-11.4 and zircon eHf(t)=-7.3~-17.4.Combined with statistical analyses of 26 zircon ages and 3 Ar-Ar ages of granitoid plutons collected from the literature,the Late Mesozoic magmatism in the Qinling can be divided into two stages.The first-stage magmatism (160~130Ma) widely occurred in the southern margin of the North China Block,the North Qinling and occasionally in the South Qinling,and has features of I-type granitoids.The second-stage magmatism (120~100Ma) characterized by transition of I-to A-type and A-type granitoids took place in the North Qinling and the eastern part of the southern margin of the North China Block.The first-stage magmatism occurred in a transition from contractional to extensional settings,while the second-stage in the extension setting.The formation of the grantoids are interpreted as partial melting of old crust,mixed with juvenile mantle component.The second-stage granitoids contain more juvenile component than the first-stage.The isotope data of the granitoids show that juvenile compositions of the basement increas from the southern margin of the North China Block to the Shangdan suture.