Fig. 1

Schematic map showing typical loess sections in the CLP and the sampling loess section. The green rectangle in c indicates the sampling segment from the upper Yushan section. a, b, and c are modified from Wang et al. (2005), An and Ho (1989), and Wu et al. (2010), respectively. The mountains along and within the CLP are indicated by black patches (a). CJW (Chenjiawo) and GWL (Gongwangling) are two important Paleolithic sites (b), where remains of Homo erectus were found since 1960s. The Yushan section is marked with a star in b. The Brunhes/Matuyama (B/M) boundary and the lower and upper boundaries of the Jaramillo (J) subchron determined by a preliminary paleomagnetic investigation are illustrated in c