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Eastern Tibetan Plateau (eastern + tibetan_plateau)
Selected AbstractsParameters of Coseismic Reverse- and Oblique-Slip Surface Ruptures of the 2008 Wenchuan Earthquake, Eastern Tibetan PlateauACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2009Xiwei XU Abstract: On May 12th, 2008, the Mw7.9 Wenchuan earthquake ruptured the Beichuan, Pengguan and Xiaoyudong faults simultaneously along the middle segment of the Longmenshan thrust belt at the eastern margin of the Tibetan plateau. Field investigations constrain the surface rupture pattern, length and offsets related to the Wenchuan earthquake. The Beichuan fault has a NE-trending right-lateral reverse rupture with a total length of 240 km. Reassessment yields a maximum vertical offset of 6.5 ± 0.5 m and a maximum right-lateral offset of 4.9 ± 0.5 m for its northern segment, which are the largest offsets found; the maximum vertical offset is 6.2 ± 0.5 m for its southern segment. The Pengguan fault has a NE-trending pure reverse rupture about 72 km long with a maximum vertical offset of about 3.5 m. The Xiaoyudong fault has a NW-striking left-lateral reverse rupture about 7 km long between the Beichuan and Pengguan faults, with a maximum vertical offset of 3.4 m and left-lateral offset of 3.5 m. This pattern of multiple co-seismic surface ruptures is among the most complicated of recent great earthquakes and presents a much larger danger than if they ruptured individually. The rupture length is the longest for reverse faulting events ever reported. [source] Geomorphic characteristics of the Minjiang drainage basin (eastern Tibetan Plateau) and its tectonic implications: New insights from a digital elevation model studyISLAND ARC, Issue 2 2006Hui-Ping Zhang Abstract The Minshan Mountain and adjacent region are the major continental escarpments along the eastern Tibetan Plateau. The Minjiang drainage basin is located within the plateau margin adjacent to the Sichuan Basin. Based on the analysis of the digital elevation model (DEM) acquired by the Shuttle Radar Topography Mission (SRTM), we know that the Minjiang drainage basin has distinct geomorphic characteristics. The regular increasing of local topographic relief from north to south is a result of the Quaternary sediment deposition within the plateau and the holistic uplift of the eastern margin of the Tibetan Plateau versus the Sichuan Basin. Results from DEM-determined Minjiang drainage sub-basins and channel profiles show that the tributaries on the opposite sides are asymmetric. Lower perimeter and area of drainage sub-basins, total channel length and bifurcation ratio within eastern flank along the Minjiang mainstream are the result of the Quaternary differential uplift of the Minshan Mountain region. Shorter stream lengths and lower bifurcation ratio might be the indications of the undergrowth and newborn features of these eastern streams, which are also representative for the eastern uplift of the Minshan Mountain. [source] Timing and style of Late Pleistocene glaciation in the Queer Shan, northern Hengduan Mountains in the eastern Tibetan Plateau,JOURNAL OF QUATERNARY SCIENCE, Issue 6 2010Liubing Xu Abstract Glacial landforms and sediments provide evidence for the existence of two Late Pleistocene major glacial advances in the Queer Shan, northern Hengduan Mountains in the eastern Tibetan Plateau. In the current study, optically stimulated luminescence and electron spin resonance dating results reveal that the two glacial advances occurred during Marine Isotope Stage (MIS) 3 and the Last Glacial Maximum (LGM) in MIS 2, respectively. Geomorphic evidence shows that the glacial advance during MIS 3 was more extensive than that in MIS 2. This glacial advance is synchronous with other glaciated areas in the Himalaya and Tibet, but contrasts with global ice volumes that reached their maximum extent during the LGM. Glaciers in the Queer Shan are of the summer accumulation type and are mainly fed by precipitation from the south Asian monsoon. Palaeoclimate proxies show that during MIS 3 the south Asian monsoon strengthened and extended further north into the Tibetan Plateau to supply more precipitation as snow at high altitudes. This in turn led to positive glacier mass balances and caused glaciers to advance. However, during the LGM, despite cooler temperature than in MIS 3, the weakened south Asian monsoon and the associated reduced precipitation were not as favourable for glacier expansion as in MIS 3. Copyright © 2010 John Wiley & Sons, Ltd. [source] A stable isotope record from freshwater lake shells of the eastern Tibetan Plateau, China, during the past two centuriesBOREAS, Issue 1 2007JINGLU WU Wu, J. L., Schleser, G. H., Lücke, A. & Li, S. 2007 (January): A stable isotope record from freshwater lake shells of the eastern Tibetan Plateau, China, during the past two centuries. Boreas, Vol. 36, pp. 38,46. Oslo. ISSN 0300,9483. Lake Xingcuo is a small, closed, hardwater lake situated in the eastern Tibetan Plateau. Stable isotope data (,18O and ,13C) from the freshwater snail Gyraulus sibirica (Dunker) in a 34-cm-long, radioactive isotope-dated sediment core represent the past 200 years of Lake Xingcuo environmental history. Carbon and oxygen isotope ratios in the shells of the snail yield information on the isotopic composition of the water in which the shell was formed, which in turn relates to climatic conditions prevailing during the snail's life-span. Living and fossil shells from Lake Xingcuo were collected. ,18O values in the living shells from Lake Xingcuo are in equilibrium with ambient waters, while ,13C values may trace snail dietary carbon. On comparing ,18O and ,13C in the shell of Gyraulus sibirica with monitored data for the period 1954,1995, we found that the ,18O composition in the shell is an efficient proxy revealing air temperature during the warmer months from April to September. There is a positive correlation between the ,18O in the shells of Gyraulus sibirica and the running average temperature of the warmer months. Climatic variability in the eastern Tibetan Plateau for the past two centuries has been inferred from the ,18O record from the freshwater snails in the sediments of Lake Xingcuo. As such, the last 200 years' palaeoclimatic record for this region can be separated into three periods representing oscillations between warm and cool conditions consistent with the Guliya ice record in the Tibetan Plateau. [source] Deep Background of Wenchuan Earthquake and the Upper Crust Structure beneath the Longmen Shan and Adjacent AreasACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2009Qiusheng LI Abstract: By analyzing the deep seismic sounding profiles across the Longmen Shan, this paper focuses on the study of the relationship between the upper crust structure of the Longmen Shan area and the Wenchuan earthquake. The Longmen Shan thrust belt marks not only the topographical change, but also the lateral velocity variation between the eastern Tibetan Plateau and the Sichuan Basin. A low-velocity layer has consistently been found in the crust beneath the eastern edge of the Tibetan Plateau, and ends beneath the western Sichuan Basin. The low-velocity layer at a depth of ,20 km beneath the eastern edge of the Tibetan Plateau has been considered as the deep condition for favoring energy accumulation that formed the great Wenchuan earthquake. [source] | ||||||||||