Mr. HU Guiming Department of Earth Sciences, HKU
A series of large rive systems flow down from Northern Tianshan mountains and across three fold-and-thrust belts. These rivers incised anticlines and synclines along the northern Chinese Tianshan mountains foreland basins, forming deep valleys. The successive fluvial terraces within anticlines and synclines were served as geological and geomorphological markers to reveal tectonic movements and the response to cyclic climate change in this region. Well preserved fluvial terraces along the middle and upper Manas river and the upper Anjihaihe river were identified during fieldwork last year. OSL dating technique was applied to place bounds on the formation and abandonment age of these river terraces. Fluvial sands on river terrace bed provide the older age limit of terrace formation, and loess sample overlain fluvial gravel layers provide the minimum constrains of abandonment age. The incision rate and the response to tectonic activities and climate change for these river terraces during late Quaternary will be investigated.