Shangzhe Zhou

The Qingzang movement: The major uplift of the Qinghai-Tibetan Plateau

Thirty-five years ago, the idea of a young Qinghai-Tibetan Plateau was proposed based on a comprehensive investigation on the Qinghai-Tibetan Plateau. This hypothesis suggested that the plateau began to rise from a planation surface (relict surface) that was less than 1000 m high formed during the Miocene to Pliocene. The fast uplift, i.e., the Qingzang Movement, began since ~3.6 Ma, evidenced by massive molasse deposits around the plateau margin and the synchronous occurrence of faulted basins within the plateau. However, later studies challenged this idea and suggested earlier (8, 14 or 35 Ma) formation of the huge plateau topography. Here we reevaluate the Qingzang Movement on the basis of our previous results and in light of new studies in the recent decades. The plateau margin has been subjected to intensive incision by very large drainages and shows the landscape characteristics of an “infant” stage of the geomorphological cycle. However, these drainages were not formed until 1.7–1.9 Ma; headwater erosion has not yet reached the hinterland of the plateau, so the interior of Tibet is free of significant erosion despite its lofty elevation, and remains an “old stage” landform. If the mean erosion rate is equivalent to the sum of clastic and soluble discharges of the modern rivers draining the Tibetan Plateau, it should have been worn down to a lowland within 8.6 Ma, ignoring tectonic uplift and isostasy. The massive conglomerate around the plateau margin began to deposit at about 3.6 Ma, indicating an increased relief after that time. Furthermore, the Hipparion fauna sites were widely distributed, and elephants, giraffes, and rhinos were abundant in the Qaidam Basin until the early Pliocene. Cenozoic climate change alone is not able to account for the dense occurrence of Hipparion fauna, unless the paleo-elevation of Tibet was lowered. The rise of Tibet since the Qingzang Movement has had a great influence on the Asian interior aridification.

Chapter 70 – Quaternary Glaciations: Extent and Chronology in China

Quaternary Glaciations in Tibetan Plateau were restricted to mountain glaciers. Four Pleistocene glaciations were identified to occurred during MIS 18~16, MIS 12, MIS 6 and MIS 4~2. The total area for the most extensive glaciation was smaller than 5×105 km2. The Kunlun-Huanghe and Gonghe tectonic uplifts of the Plateau have played the very important role in triggering glaciations in the high Asia region.

Glacial geomorphology of the Parlung Zangbo Valley, southeastern Tibetan Plateau

ABSTRACT We present a glacial geomorphological map (1:825,000) of the Parlung Zangbo Valley in the southeastern Tibetan Plateau based on Google Earth imagery and the 30u2005m ASTER Global Digital Elevation Model (ASTER GDEM). The mapped region covers 2.9u2009×u2009104u2005km2, including abundant glacial landforms such as glacial valleys, marginal moraines (including terminal moraines and lateral moraines), and hummocky moraines. Glacial valleys are distributed mainly above 2100u2005m a.s.l. with lengths from 1 to 130u2005km. Multiple marginal moraines occur along the glacial valleys, indicating the presence of multiple glacial events. The lowest moraines are distributed mainly at the mouth of each valley between 2400 and 4000u2005m a.s.l. Hummocky moraines are mainly distributed in the two main tributary valleys: the Bodui Zangbo Valley and the Yigong Zangbo Valley. One ice-dammed paleolake was mapped with a surface area of 12.5u2005km2. The mapped glacial features (including contemporary glaciers) cover 1.2u2009×u2009104u2005km2, about 40% of the mapped area, representing the minimum extent of maximum glaciation. This map provides a useful data set for reconstructing the timing and extent of paleoglaciations in this area.