Zircon U-Pb chronology of the Jianping Complex: Implications for the Precambrian crustal evolution history of the northern margin of North China Craton

The Neoarchean to Paleoproterozoic Jianping complex in the western Liaoning province is an important component of the Precambrian basement of the North China Craton. This region connects the Neoarchean Fengning-Chengde complex in the west, the Neoarchean to Paleoproterozoic North Chaoyang complex in the northeast and the Yixian-Fuxin Archean greenstone belt in the east. The Precambrian Jianping complex is dominantly composed of metamorphosed supracrustal sequence and dioritic to granitoid gneisses (tonalite-trondhjemite-granodiorite, TTG). Here we present results from LA-ICPMS zircon U-Pb isotope dating from the various lithological units in this complex, which reveal that the magmatic precursors of the metavolcanic rocks associated with the supracrustal sequence were generated during 2555-2550 Ma, and up to 2615 Ma. A major magmatic pulse of dioritic to granitic suite occurred during 2538 to 2495 Ma. This was followed by ca. 2485 Ma granulite facies metamorphism and a retrograde event at ca. 2450-2401 Ma. Our data also reveal a major charnockite emplacement event in this region at ca. 1694 Ma. Integrating our new results with the available geologic and previous geochronological data, we identify three major growth stages in the crustal evolution history of the northern margin of the Eastern Continental Block of the North China Craton at ca. 2550-2495 Ma, ca. 2403-2394 Ma, and ca.1700 Ma. The LA-ICP-MS zircon data provide new insights on the Neoarchean to Paleoproterozoic tectonothermal evolution history in the northern margin of the Eastern Continental Block of the North China Craton. (C) 2011 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.