STRATIGRAPHIC EVIDENCES FOR DATING OF THE FORELAND THRUST, NORTH TIANSHAN

The Kalazha anticline is a structure of the first foreland fold-thrust belt in north Tianshan, near Urumuqi. Growth strata recorded accurately initial emplacement ages of structure and detailed forming processes. Stratigraphy analysis of Kalazha anticline and its adjacent area indicates that the Changjihe group(N1-2ch) is a set of growth strata. The Chanagjihe group (N1-2ch), which is belongs to Pliocene, is equivalent to Dushanzi formation (N1-2d) in sedimentation time. This conclusion proved that the first fold-thrust belt of north Tianshan, including the Kalazha anticline, initiated in late Miocene to the earliest Pliocene, and formed after that time.