NEW CONTRIBUTIONS TO CHINESE PLIOPLEISTOCENE MAGNETOSTRATIGRAPHY

A new collection of over 500 orientated hand-samples (of which 180 are red clays) from a 195 m loess/red clay section near Xian (109-degrees 12' E, 34-degrees 12' N), China, has been dated by magnetic stratigraphy. Biostratigraphic and previous magnetostratigraphic investigations gave a maximum age for the Chinese loess of 2.4 Ma, implying that the underlying Red Clay Formation is Pliocene in age. The present study yields a clearly defined magnetic polarity stratigraphy in good agreement with a polarity time scale developed by earlier workers. An interpretation of this magnetostratigraphy suggests a basal age for the loess series in this region of 2.5 Ma. and a minimum age for the base of the Red Clay Formation, which is also the base of the section, of 5.0 Ma