Late Cenozoic tectonic movement in the front of the West Kunlun Mountains and uplift of the northwestern margin of the Qinghai-Tibetan Plateau

Abstract：The Late Cenozoic geomorphologic and sedimentary features in the West Kunlun Mountain front record the uplift process of the West Kunlun Mountains and the western margin of the Qinghai-Tibet Plateau. Based on geomorphologic and paleomagnetic studies, the Late Cenozoic tectonic movement in the West Kunlun are discussed. At about 25 Ma, significant change took place in sedimentary features in the West Kunlun Mountain front, reflecting that the West Kunlun began to be uplifted, and at about 5 Ma, molasse developed in the West Kunlun Mountain front, indicating that the West Kunlun began to be uplifted rapidly. Paleomagnetic results show that marked clockwise rotational movements occurred in the Eocene-Miocene, while vertical movements resulting from horizontal compression have predominated in the Quaternary and no marked rotational movement during this period. The downward incision of the rivers in the West Kunlun at about 1.2 Ma gave rise to terraces. Since the Mid-late Quaternary, the magnitude and frequency of the tectonic uplift have increased, and a rapid tectonic uplift event took place in the middle Holocene (at about 5 ka).