Researches on the sediments, paleocurrents and depositional environments of the Early Cretaceous in northern Qilian-Jiuxi areas show that an extensive basin (Northern Qinlian-Jiuquan Lake), covering areas from the mid-Qinlian Mountains in the south to the Beishan in the north and from the western Altyn Fault to Jiudong in the east, existed in the Early Cretaceous. Current study indicates that the