QIN Ya1，LIANG Yi-hong2，ZHANG Qing-wei1，BAI Ling-an1，ZOU Cun-ming2
(1. College of Earth Sciences, Guilin University of Technology, Guilin 541004, China;
2. College of Earth Sciences, Jilin University, Changchun 130061, China)
Abstract：This paper studies the chronology of plagioclase amphibolite from Shensixian mafic dyke swarms in Liaodong area, China by using LA-ICP-MS zircon U-Pb dating．Zircons show irregular, elliptical and harbor-like morphology, indicating that they suffered effect of late tectonothermal event. CL images indicate that the zircon is characterized by sector and cedar-leaf zoning or no zoning. The zircons have Th/U ratios varying from 0.03 to 0.14. The characteristics described above indicate that the zircons are of a typical metamorphic origin. Twenty analysis on the zircons gave a weighted mean 207Pb/206Pb age of 1874±31 Ma, which is interpreted to be the metamorphic age of the dated amphibolite. This metamorphic age of 1874±31 Ma represents the time of regional metamorphism resulting from the closure of Liaoji Paleoproterozoic rift located in the eastern part of the North China Craton．
Keywords：zircon U-Pb dating; mafic dyke swarm; Liaoning Province
ACTA MINERALOGICA SINICA Vol. 35, No. 4, 2015, Page 540-544
