Zircon U–Pb age, trace element and Hf isotope composition of Kongling terrane in the Yangtze Craton: refining the timing of Palaeoproterozoic high‐grade metamorphism

Abstract

U-Pb age, trace element and Hf isotope compositions of zircon were analysed for a metasedimentary rock and two amphibolites from the Kongling terrane in the northern part of the Yangtze Craton. The zircon shows distinct morphological and chemical characteristics. Most zircon in an amphibolite shows oscillatory zoning, high Th ⁄ U and 176 Lu ⁄ 177 Hf ratios, high formation temperature, high trace element contents, clear negative Eu anomaly, as well as HREE-enriched patterns, suggesting that it is igneous. The zircon yields a weighted mean 207 Pb ⁄ 206 Pb age of 2857 ± 8 Ma, representing the age of the magmatic protolith. The zircon in the other two samples is metamorphic. It has low Th ⁄ U ratios, low trace element concentrations, variable HREE contents (33.8 ‡ Lu N ‡2213; 14.7 £ Lu N ⁄ Sm N £ 354) and 176 Lu ⁄ 177 Hf ratios (0.000030-0.001168). The data indicate that the zircon formed in the presence of garnet and under upper amphibolite facies conditions. The metamorphic zircon yields a weighted mean 207 Pb ⁄ 206 Pb age of 2010 ± 13 Ma. These results combined with previously obtained Palaeoproterozoic metamorphic ages suggest a c. 2.0 Ga Palaeoproterozoic collisional event in the Yangtze Craton, which may result from the assembly of the supercontinent Columbia. The zircon in two samples yields weighted mean two-stage Hf model (T DM2 ) ages of 3217 ± 110 and 2943 ± 50 Ma, respectively, indicating that their protoliths were mainly derived from Archean crust.

Formation and evolution of Precambrian continental lithosphere in South China

“…Zircon U-Pb dating reveals that major TTG magmatism occurred at 2.85-2.95 Ga and minor at 3.2-3.3 Ga (Qiu et al, 2000;Zhang et al, 2006a;J.P. Zheng et al, 2006b;Jiao et al, 2009;Wu et al, 2009;S. Gao et al, 2011d).…”

“…Qiu et al (2000) reported a few zircon grains with concordant SHRIMP U-Pb ages of 1.99 Ga and 1.93 Ga from gneiss in the Kongling complex. Some migmatites, metasedimentary gneisses and amphibolites in the Kongling complex also exhibit zircon U-Pb ages of 1.9-2.0 Ga and variably negative ε Hf (t) values Wu et al, 2009), suggesting the reworking of Archean crust. Xiong et al (2009) and M. Peng (2012a) identified an A-type granite with zircon U-Pb ages of 1.85 Ga and ε Hf (t) values of −26.3 to −16.7 in the Kongling complex.…”

U–Pb ages and trace elements of detrital zircons from Early Cretaceous sedimentary rocks in the Jiaolai Basin, north margin of the Sulu UHP terrane: Provenances and tectonic implications

“…A large number of U-Pb ages were obtained for sedimentary, igneous and metamorphic rocks from the Yangtze Block, showing that the late Paleoproterozoic is also an important period of Precambrian tectonic evolution (X.M. Peng et al, 2009;Wu et al, 2008bWu et al, , 2009aXie et al, 2009;S.B. Zhang et al, 2006a,b).…”

Discovery of Paleoproterozoic rapakivi granite on the northern margin of the Yangtze block and its geological significance

“…[34] and mixed rocks (1980-2013 Ma, SHRIMP) [83]. These chronological records are distributed across the northern margin of the Yangtze block, and may represent a collisional orogenic events [34] related to the amalgamation of the Columbia supercontinent [29,34,35].…”

“…Kongling Complex) are rare in the Yangtze block [25][26][27][28]. Even so, recent studies have shown that there are chronological records of 1.8-2.1Ga tectonothermal events in the Yangtze block [29][30][31][32][33][34][35][36][37][38]. Some of these studies indicates that these events may be related to the amalgamation and breakup of the Columbia supercontinent [34][35][36][37][38].…”