摘要
This paper carries out studies about LA-ICPMS U–Pb dating and Hf isotopic compositional analysis for detrital zircons in two metasedimentary samples that were taken from the Zhaochigou Formation-complex in the Helan Mountain.The results show that the Zhaochigou Formation-complex formed*1.96 Ga,and it is a part of the Khondalite Series that is widespread in the North China Craton(NCC).The age spectrum of the detrital zircons indicates that the Zhaochigou Formation-complex shared the same provenance with the eastern edge of the Khondalite Series.Products of ancient magmatic activities within the Khondalite Belt may be the major source for the sedimentary materials that formed the Khondalite Series.Our age-dating results suggest that the Khondalite Series in the NCC may have experienced two stages of metamorphism,as the early stage occurred during 1.96–1.95 Ga,and the later stage occurred at about 1.87 Ga.The Hfisotopic data indicate that the Western Block of the NCC endured a stage of crustal growth at 2.5–2.3 Ga.
This paper carries out studies about LA-ICP- MS U-Pb dating and Hf isotopic compositional analysis for detrital zircons in two metasedimentary samples that were taken from the Zhaochigou Formation-complex in the Helan Mountain. The results show that the Zhaochigou Formation-complex formed - 1.96 Ga, and it is a part of the Khondalite Series that is widespread in the North China Craton （NCC）. The age spectrum of the detrital zircons indicates that the Zhaochigou Formation-complex shared the same provenance with the eastern edge of the Khondalite Series. Products of ancient magmatic activities within the Khondalite Belt may be the major source for the sedimentary materials that formed the Khondalite Series. Our age-dating results suggest that the Khondalite Series in the NCC may have experienced two stages of metamorphism, as the early stage occurred during 1.96-1.95 Ga, and the later stage occurred at about 1.87 Ga. The Hf isotopic data indicate that the Western Block of the NCC endured a stage of crustal growth at 2.5-2.3 Ga.
基金
supported by the Key Project of National Natural Science Foundation of China(41230206)
the project of China Geological Survey(1212011120552)
