New paleomagnetic results from the ca. 1.0 Ga Jiayuan Formation of the Huaibei Group in the North China craton, and their paleogeographic implications

Abstract

The Rodinia supercontinent formed in the transition between Mesoproterozoic and Neoproterozoic. The high-quality paleomagnetic poles around 1000 Ma, however, are rather scarce in the global paleomagnetic database, hindering a well-calibrated paleogeographic reconstruction for when and how Rodinia assembled. The late Mesoproterozoic to early Neoproterozoic Huaibei Group strata (ca. 1120–890 Ma) exposed at the southeastern margin of the North China craton (NCC) provide great promise for paleomagnetism. In this study, we mainly report a new paleopole (54.2 °S, 111.4 °E, A95 = 5.1°) obtained from the upper Jiayuan Formation in the middle Huaibei Group by incorporating our new data with the previously published virtual geomagnetic poles. That average pole passed a positive fold test and a positive reversal test, along with the pole’s distinctiveness from younger poles of the NCC, support the interpretation that the remanence is primary. New detrital zircon U–Pb age analyses of a sandstone sample of the Jiayuan Formation and the mafic sills intruding the overlying strata dated previously together constrain the depositional age of the Jiayuan Formation to be between ca. 1089 and ca. 945 Ma. Our new data, incorporated with other poles previously reported from the Huaibei Group and the mafic sills intruding the strata, reveal that the NCC underwent large-scale paleolatitudinal shifts from the polar region to low latitudes across the transition between Mesoproterozoic and Neoproterozoic. Matching the apparent polar wander paths of the NCC and Laurentia suggests that they together drifted from the polar region in the northern hemisphere at ca. 1110 Ma to moderate latitudes in the southern hemisphere around 1000 Ma during the assembly of Rodinia.