DATING VERTEBRATE MICROFAUNAS IN THE LATE NEOGENE RECORD OF NORTHERN CHINA

Chinese paleontologists have ordered Neogene strata in lime on the bas is of their contained fossils, small mammals in particular, but biochr onology alone attains limited accuracy in a biogeographically restrict ed system. The chronology of terrestrial sediments can be refined when sound systematics of the contained fossils is combined with paleomagn etic data. The geomagnetic polarity time scale has proven to be a usef ul independent reference system for dating the biochronology of contin ental deposits in North China. Long composites of successive microfaun as, with faunal correlation at times of low endemism, and age estimati on through paleomagnetic correlation, yield robust biochronologies tha t are well constrained in time. The Yushe Basin (Shanxi Province) sequ ence, which has magnetostratigraphic control, provides a key reference for the late Neogene of North China. Data from Yushe Basin identify t he microfauna characteristic at the time of the Miocene/Pliocene bound ary in northern China. The assemblage from near the village of Jiayucu n strongly resembles the rich microfauna of Ertemte, Inner Mongolia, a nd occurs at the base of a reversed magnetozone correlated with Chron C3r (early Gilbert Chron), latest Miocene. Successive Pliocene age ass emblages from Yushe Basin resemble the Jingle and Youhe local faunas, which were formerly used as reference faunas for North China. Nihewan- like assemblages are correlated with the Matuyama Chron, some being pr e-Olduvai Subchron, and therefore Pliocene in age by current definitio n. Later Pleistocene time is represented in Yushe Basin by fossil site s in loam deposits, The well-known loess sequence of central China, an d other Plio/Pleistocene reference faunas yield a date of ca. 1 Ma for a reddish loam microfauna from Yushe Basin. (C) 1997 Elsevier Science B.V.