Provenance and tectonic significance of late Mesoproterozoic detrital zircons from the Tonian system, northern margin of the North China Craton

摘要

The involvement of the North China Craton (NCC) in the assembly or breakup of Rodinia has long been debated. Studies of palaeomagnetism, mafic sills (dikes), igneous events, and sedimentary records have led to contrasting opinions on this topic. No igneous events related to the late Mesoproterozoic assembly of Rodinia have been reported in the NCC. However, the authors found numerous late Mesoproterozoic zircons in the Tonian system on the northern margin of the NCC. The Tonian Zhulazhagamaodao formation is composed of meta-sandstone, siltstone, slate, carbonate, and dolomine of the littoral to neritic facies and occurs mainly in the western part of the Bayan Obo-Zhaertai-Langshan rift. U-Pb dating of detrital zircons from the Tonian system reveals age peaks at 1079 +/- 23 Ma, 1092 +/- 22 Ma, 1175 +/- 50 Ma, 1175 +/- 18 Ma, 1260 +/- 45 Ma, 1266 +/- 16 Ma, and 1270 +/- 26 Ma, which correspond to the timing of Rodinia assembly. Considering that coeval igneous rocks and orogenic belts developed mostly in the Laurentia-Baltica cratons, we propose that these cratons supplied clastic material to the northern margin of the NCC and that they had a close spatial relationship between each other during the Tonian.