克里雅河下游沉积物的光释光年龄与晚更新世末以来沙漠的形成  

OSL chronology reveals Late Pleistocene floods and the impact on landform evolution at the lower reaches of the Keriya River in the Taklamakan Desert

作　　者：张峰[1] 王姣 马丽 迪丽拜尔·吐尔孙 ZHANG Feng;WANG Jiao;MA Li;TURSUN·Dilibaier(Key Laboratory of Oasis Ecology(Xinjiang University)Ministry of Education,Urumqi 830046,China)

机构地区：[1]新疆大学教育部绿洲生态重点实验室,乌鲁木齐830046

出　　处：《地理学报》2021年第9期2240-2252,共13页Acta Geographica Sinica

基　　金：国家自然科学基金项目(U1503381,40701188,41161034);国家科技基础资源调查专项课题(2017FY101004);新疆维吾尔自治区天山雪松人才项目(2017XS21)。

摘　　要：有关塔克拉玛干沙漠演化的年代学数据尚少,本文在地貌认知较少的克里雅河下游沙漠深处的圆沙和喀拉墩一带16处剖面获取了18件河流沉积光释光(OSL)年龄。新测得的年龄数据分布于3.4—44.1 ka。全新世样品多分布于圆沙与喀拉墩干三角洲及其之间的地区,年龄集中在11 ka、8—9 ka、5—6.5 ka、4.6 ka与3.4—3.7 ka。深海氧同位素3阶段(MIS3)样品位置在克里雅河与和田河之间,分布在约38—47 ka前后。末次冰期冰盛期(LGM)末样品分布在通往圆沙古河道的西侧,年龄在14.5 ka前后。根据沉积物样品及年代学数据认为:克里雅河下游曾在MIS3阶段末、LGM末与全新世多次发生洪泛;数次的洪泛事件对克里雅河下游地貌发育产生重要影响;克里雅河下游干三角洲及现代河流西侧的流动沙丘主要形成于全新世,与前人"发育于汉唐以来"的观点不完全一致。克里雅河下游河流沉积发生时间与塔里木盆地周缘山脉冰进冰消有一定对应,暗示气候变化可能间接影响着塔克拉玛干沙漠沙丘的发育。Climate change impacts on the relationship between fluvial processes and dunes landform evolution have been a research topic. However, the chronology data used to examine such relationship are deficient. The Keriya River has a glacial origin in the Kunlun Mountains at the south margin of the Tarim Basin. The river flows into the Taklamakan Desert, the second largest shifting dunes desert in the world. The dry channels and shifting dunes in the area provide an ideal opportunity to understand fluvial and eolian landform evolution processes and their relationship with climate change. We investigated this area from 2008-2011, and obtained18 fluvial sediment samples from 16 sections for optically stimulated luminescence(OSL)dating. Results show that the ages are ranged from 3.4-44.1 ka. Most(13) samples were from the Holocene, around 11 ka, 8-9 ka, 5-6.5 ka, 4.6 ka and 3.4-3.7 ka respectively. which were distributed along ancient river channels around Yuansha and Karadun. Two samples close to the Hotan River(38-47 ka) fall in the Marine Isotope Stages 3(MIS3). Three samples(of one section) were located near ancient channels flowing towards the Yuansha Site aged around 14.5 ka, the Last Glacial Maximum(LGM). The sediment samples and OSL ages of this work suggest that the Keriya River was flooded in the Holocene, the LGM and the MIS3 stage.Fluvial sediment provided source material for dunes and fluvial processes impacted landform evolution at the lower reaches of the Keriya River. Our results suggest that most dunes covered on fluvial sediments at the lower reaches and west of the Keriya River developed since the Holocene. This differs from previous works suggesting that they developed "since the Han and Tang dynasties". The OSL ages of fluvial sediments were consistent with the reported deglaciation(after glacial advance) ages in alpine mountains surrounding the Tarim Basin. This suggests that climate fluctuation might have impacted the occurrence of floods and the formation of dunes in the Taklamakan Desert.

关 键 词：塔克拉玛干沙漠 洪泛 沙丘 MIS3 LGM 全新世 冰消 

分 类 号：P512.2[天文地球—地质学] P931.3