晚第四纪以来青藏羌塘高原令戈错水位变化与光释光年代学研究

令戈错 水位变化 青藏高原 晚第四纪 光释光测年
潘宝林 2014-01 项目
Lakes are the important components of the Tibet plateau Geomorphic system. Lake level changes and the lake areas are sensitive to climate change.With the development of the dating methods , the plateau lakes are gripping many scientist. Linggo Co lies to west of the Tanggula Mountains (88.52-88.64 E, 33. 79-33.91 N), 95 km away from the Shuanghu town in south and 40 km away from the west of the puruogangri ice field (PIF), the largest glacier group in the Tibetan Plateau (TP) with an area of over 400 km2. It is elonged in S-N with a surface area of 100 km2 and an elevation of 5059 m a.s.l. with palaeoshorelines around the lake. Linggo Co is mainly drained by a glacier-melt water river from the west slope of the ice field as well as lots of small inland seasonal rivers. In this area, the survey on the geology and geomorphology had been done some time ago, but it was lack of the absolute ages on the changes of palaeolevel of the lake, especially the ages of the high levels. Based on the geomorphologic investigation and measurement to Linggo Co in the field, this study propose to find the frequency and scale of the lake level changes. Then, this study will built the absolute ages of the lake level from the Late Pleistocene by the dating the ages of the samples from the lake shorelines, terraces of the river emptied into the lake and desert in the edge of the puruogangri ice field via (OSL) optically stimulated luminescence, cosmogenic radionuclides (CRN) and restore the spatio-temporal variability of the lake, and discuss the palaeoclimate in the area. Not only has this study very important scientific meanings to know the evolution of the Quaternary climate in the area,but also let me understand the palaeoclimate of the lake highlevels in Tibet Plateau.
湖泊是青藏高原地貌系统的重要组成部分,湖泊水位和面积对气候变化响应敏感,是气候变化的水位计。随着测年手段的发展,高原湖泊环境变化研究又掀起了一轮高潮。令戈错位于羌塘高原中东部,湖水主要依赖普若岗日冰川融水补给,湖泊古湖岸线发育。令戈错地区的地质地貌调查很早就已开展,但仍缺乏约束湖泊演化、古水位变化的绝对年龄,特别是缺乏高水位的年代控制。本项目拟对青藏高原腹地的令戈错进行野外地貌调查和测量,查清该湖泊晚第四纪以来古水位的时空变化;在此基础上,利用先进的测年手段(OSL、CRN),对湖岸阶地、河流阶地、冰缘沙漠年代样品测定,建立令戈错晚第四纪以来湖泊水位变化的绝对年代,恢复湖泊古水位时空变化,探讨古气候对该地区湖泊水位变化的影响,这将为第四纪湖泊地貌学研究增添新的内容,加深对青藏高原高湖面古气候的理解。