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The Quanji Block, situated between the northern margin of the Qaidam Block and the South Qilian orogenic belt in the NE Qinghai-Tibet Plateau, China, is thought to represent a remnant continental crust. In this study, LA-ICPMS U-Pb analyses of detrital zircon grains from two mesosomes in the migmatitic Dakendaban Group yield ages of 2467+28/-26 Ma and 2474+66/-52 Ma, respectively. Zircon grains from a leucosome give two distinct ages of 2471+18/-16 Ma and 1924+14/-15 Ma. Zircon from a granitic pegmatite that intruded into the Dakendaban Group yields an age of 2427+44/-38 Ma. These data suggest that the Early Paleoproterozoic Dakendaban Group deposited between ~2.43 to ~2.47 Ga and has been subject to an intrusive event at 2.43 Ga, and regional metamorphism-anatexis at 1.92 Ga. The common lower intercept age of ~0.9 Ga probably records a significant Early Neoproterozoic event in the Quanji Block.
The Quanji Block, situated between the northern margin of the Qaidam Block and the South Qilian orogenic belt in the NE Qinghai-Tibet Plateau, China, is thought to represent a remnant continental crust. In this study, LA-ICPMS U-Pb analyzes of Detrital zircon grains from two mesosomes in the migmatitic Dakendaban Group yield ages of 2467 + 28 / -26 Ma and 2474 + 66 / -52 Ma, respectively. Zircon grains from a leucosome give two distinct ages of 2471 + 18 / -16 Ma and 1924 + 14 / -15 Ma. Zircon from a granitic pegmatite that intruded into the Dakendaban Group yield an age of 2427 + 44 / -38 Ma. These data suggest that the Early Paleoproterozoic Dakendaban Group deposited between ~ 2.43 to ~ 2.47 Ga and has been subject to an intrusive event at 2.43 Ga, and regional metamorphism-anatexis at 1.92 Ga. The common lower intercept age of ~ 0.9 Ga probably records a significant early Neoproterozoic event in the Quanji Block.