Timing of the Nihewan formation and faunas

Abstract

Magnetostratigraphic dating of the fluvio-lacustrine sequence in the Nihewan Basin, North China, has permitted the precise timing of the basin infilling and associated Nihewan mammalian faunas. The combined evidence of new paleomagnetic findings from the Hongya and Huabaogou sections of the eastern Nihewan Basin and previously published magnetochronological data suggests that the Nihewan Formation records the tectono-sedimentary processes of the Plio–Pleistocene Nihewan Basin and that the Nihewan faunas can be placed between the Matuyama–Brunhes geomagnetic reversal and the onset of the Olduvai subchron (0.78–1.95 Ma). The onset and termination of the basin deposition occurred just prior to the Gauss–Matuyama geomagnetic reversal and during the period from the last interglaciation to the late last glaciation, respectively, suggesting that the Nihewan Formation is of Late Pliocene to late Pleistocene age. The Nihewan faunas, comprising a series of mammalian faunas (such as Maliang, Donggutuo, Xiaochangliang, Banshan, Majuangou, Huabaogou, Xiashagou, Danangou and Dongyaozitou), are suggested to span a time range of about 0.8–2.0 Ma. The combination of our new and previously published magnetostratigraphy has significantly refined the chronology of the terrestrial Nihewan Formation and faunas.