Fig. 1.

Map of North China, highlighting the Yanliao rift where the Xiamaling Formation is found. Reported locations of the Xiamaling Formation are indicated. Unit 5 IF has been reported both at Xiahuayuan, where we have done our sampling, and at Jixian (see text for details). Also shown are locations of diabase activity and where tuff layers have been reported. Finally, photos show the Xiamaling IF in outcrop with lines indicating locations. In the outcrop photo in Upper Right, the transition between units 5 and 4 (alternating red/green sediment) is seen in the lower left of the photo.