Zircon Hf Isotope of Yingfeng Rapakivi Granites from the Quanji Massif and -2.7 Ga Crustal Growth

• Published in: Journal of earth science (Wuhan, China) Vol. 24; no. 1; pp. 29 - 41
• Main Author: 陈能松 龚松林 夏小平 耿红燕 王璐 孙敏 Timothy M Kusky
• Format: Journal Article
• Language: English
• Published: China University of Geosciences China University of Geosciences 01.02.2013; Springer Nature B.V
• Subjects: Age; Biogeosciences; China; Cratons; Earth and Environmental Science; Earth science; Earth Sciences; Gallium; Geochemistry; Geology; Geotechnical Engineering & Applied Earth Sciences; Granite; Hafnium; ICP-MS技术; Isotopes; Massifs; Metamorphic rocks; Minerals; Plate tectonics; U-Pb年龄; 中国西北地区; 地块; 地壳生长; 环斑花岗岩; 锆石Hf同位素; China, People's Rep., North China Craton; China, People's Rep; Tarim-North China Craton; crustal growth; tectonic evolution; zircon Hf isotope; rapakivi granite; Quanji Massif
• ISSN: 1674-487X; 1867-111X
• DOI: 10.1007/s12583-013-0309-2

The Quanji （全吉） Massif is located in the Northwest China, which is interpreted as a micro-continent that is composed of metamorphic basement and stable cover strata. There are some controversies of genetic relationship between the Quanji Massif and the major cratons in China. In this study, we obtained in situ zircon U-Pb and Hf isotopic compositions of the Yingfeng （鹰峰） rapakivi granites from the northwest Quanji Massif by application of LA-MC-ICP-MS technique. Twenty U-Pb age measurements points are concordant or near concordant, and their weighted mean 207pb/206pb age is 1 793.9±6.4 Ma （MSWD= 1.09）, yields an upper intercept age of 1 800±17 Ma （MSWD=0.41）; 19 Hf isotope measurements yield a two-stage Hf model ages （TDM2） of 2.63 to 2.81 Ga, with a weighted average age of about 2.70±0.02 Ga and till（t）values variate between -8.91 to -5.35. This indicates that magma source of the Yingfeng rapakivi granites were produced from partial melting of late stage of Neoarchean juvenile crust, and suggests a significant crustal growth event occurred in the Quanji Massif at that time. The Quanji Massif might be an ancient continental segment detached from the Tarim Craton based on the crustal growth history and other geological records. The Tarim Craton （including the Quanji Massif） and the North China Craton had a similar or homological early crustal evolution around -2.7 Ga, which implies that Tarim Craton might be one of the component parts of North China Craton. of the Yingfeng rapakivi granites were produced from partial melting of late stage of Neoarchean juve- nile crust, and suggests a significant crustal growth event occurred in the Quanji Massif at that time. The Quanji Massif might be an ancient continental segment detached from the Tarim Craton based on the crustal growth history and other geological records. The Tarim Craton （including the Quanji Massif） and the North China Craton had a similar or homological early crustal evolution around -2.7 Ga, which implies that Tarim Craton might be one of the component parts of North China Craton.