Precambrian tectonic affinity of theNorthQinlingMicrocontinent: Constraints from the discovery ofMesoproterozoic magmatic zircons in theQinlingGroup

Abstract

This paper presents new results on zircon U–Pb dating of a two‐mica schist from the Qinling Group in the core of the North Qinling Orogenic Belt (NQB), Central China, with the aim of constraining the formation time of the Qinling Group, and the tectonic affinity of the North Qinling Microcontinent. Zircon U–Pb dating indicates that the protolith of the metasedimentary rock in the Qinling Group was deposited later than ~1502 Ma. The Qinling Group in the NQB represents a long‐lived unit, and its formation age can be constrained to the period between the Paleoproterozoic and early Neoproterozoic. The zircon age populations of the studied sample can be divided into two major populations of 1559–1642 and 1470–1548 Ma, and one subordinate population of 1717–1794 Ma, indicating their provenances were mainly attributed to the NQB and subordinately from the North China Craton (NCC) and the Yangtze Craton (YZC). And the distribution of the early Neoproterozoic magmatic events and the Nd–Pb whole‐rock isotopes, zircon Hf isotopes, and trace element compositions of the Precambrian basement rocks in the NQB is significantly different from those in the NCC and YZC, indicating that the NQB cannot be a southern sector of the NCC, or a northern sector of the YZC, and was an independent microcontinent from the Paleoproterozoic to the early Neoproterozoic.