img

官方微信

img

群号:冰川冻土交流群

QQ群:218834310

高级检索

冰川冻土 ›› 2017, Vol. 39 ›› Issue (3): 549-562.doi: 10.7522/j.issn.1000-0240.2017.0062

• 冰冻圈与全球变化 • 上一篇    下一篇

黄河源区玛曲段末次冰消期古洪水事件及其光释光测年研究

陈莹璐1,2, 黄春长1,2, 张玉柱3, 郭永强1,2, 周亚利1,2, 査小春1,2, 庞奖励1,2, 石彬楠1,2, 刘雯瑾1,2   

  1. 1. 陕西师范大学 地理科学与旅游学院, 陕西 西安 710062;
    2. 陕西师范大学 地理学国家级实验教学示范中心, 陕西 西安 710062;
    3. 西北大学 城市与环境学院, 陕西 西安 710127
  • 收稿日期:2017-03-28 修回日期:2017-06-28 出版日期:2017-06-25 发布日期:2017-09-09
  • 通讯作者: 黄春长,E-mail:cchuang@snnu.edu.cn;张玉柱,E-mail:xbdzyz05@nwu.edu.cn E-mail:cchuang@snnu.edu.cn;xbdzyz05@nwu.edu.cn
  • 作者简介:陈莹璐(1993-),女,广西柳州人,2015年毕业于广西师范大学,现为陕西师范大学在读硕士研究生,从事资源开发与环境演变研究.E-mail:m18089209061@163.com
  • 基金资助:
    国家自然科学基金项目(41771110);中国博士后科学基金项目(2016M592829)资助

Study of the sedimentology and OSL dating of the Last Deglaciation paleoflood events along Maqu section in the source regions of the Yellow River

CHEN Yinglu1,2, HUANG Chunchang1,2, ZHANG Yuzhu3, GUO Yongqiang1,2, ZHOU Yali1,2, ZHA Xiaochun1,2, PANG Jiangli1,2, SHI Binnan1,2, LIU Wenjin1,2   

  1. 1. School of Geography and Tourism, Shaanxi Normal University, Xi'an 710062, China;
    2. National Demonstration Center for Experimental Geography Education, Shaanxi Normal University, Xi'an 710062, China;
    3. College of Urban and Environmental Science, Northwestern University, Xi'an 710127, China
  • Received:2017-03-28 Revised:2017-06-28 Online:2017-06-25 Published:2017-09-09

摘要: 通过对黄河源区玛曲段河谷开展野外考察,在太吾若(TWR)发现典型的古洪水滞流沉积剖面。根据野外沉积学宏观特征判别,并结合粒度分布、磁化率、地球化学元素和石英颗粒微形态特征等室内实验分析测定结果,准确鉴别出TWR剖面所夹一组多层洪水滞流沉积物(SWD),属典型的河流洪水在高水位滞流环境下沉积的悬移质泥沙。结果表明,TWR剖面古洪水SWD和现代洪水SWD沉积学分类为沙质粉沙,现代土壤为黏土质粉沙,现代风成沙为中沙。古洪水SWD粒度自然分布频率曲线为正偏,呈单峰,主峰高且峰值集中,分选性良好。古洪水SWD和现代洪水SWD磁化率较低,介于现代土壤和现代风成沙之间,化学元素明显区别于现代土壤和现代风成沙,表明它们尚未受到风化成壤作用影响,为古洪水悬移质快速沉积形成的滞流沉积物。石英颗粒微形态特征的分析表明,古洪水SWD和现代洪水SWD石英颗粒表面分布明显的三角痕、V形坑、撞击坑和凹面等水成沉积物的典型特征,属于河流沙类型。采用单片再生剂量法(SAR)光释光技术测年,证明在13.6~13.0 ka BP,黄河源地区经历了一期多次的大洪水事件,发生时段对应末次冰消期向全新世转折的时期,与欧洲和格陵兰冰芯记录末次冰消期中的Bolling/Aellrod暖期相对应,此时青藏高原地区冰川大规模消融,这期古洪水事件正是流域内冰融水大量下泄汇入黄河而形成的大洪水。

关键词: 古洪水, 末次冰消期, 光释光, 气候变化, 黄河源区

Abstract: Pedo-sedimentological investigations were carried out in the source regions of the Yellow River. A set of paleoflood slack water deposits (SWDs) was identified along Maqu section of the Yellow River based on sedimentary criteria and analytical results, which contain climate and hydrological information. Sediment samples were systematically taken from loess-soil profiles at Taiwuruo study site and magnetic susceptibility, grain-size distribution, geochemical elements and micromorphology were analyzed in laboratory for identifying the paleoflood SWDs. The results show that these SWDs are defined as sandy silt, which are similar to the modern flood SWD; the modern soil is defined as clayey silt; the modern aeolian sand is defined as medium sand. The shape of particle size distribution curve of the paleoflood SWDs is very similar to that of the modern flood SWD, very different from modern aeolian sand and modern soil. The magnetic susceptibility of the paleoflood SWDs and the modern flood SWD are slightly higher than that of the modern aeolian sand, but significantly lower than that of the modern soil. Chemical elements of the paleoflood SWDs are distinctly different from modern soil and modern aeolian sand. The analysis of the morphological characteristics of the quartz particles shows that the surface of the paleoflood SWD and the modern flood SWD are distributed with V-shaped pits, triangular marks, concave surfaces typically caused by physical collision and friction in running water. The morphological characteristics of the quartz particles reflect different microscopic differences in sedimentary environment. Analytical results, including magnetic susceptibility, particle-size distribution, concentrations of chemical elements and micromorphology, indicate that these well-sorted paleoflood SWDs were deposited from the suspended sediment load in floodwaters. This hydro-climatic event was dated to 13.6-13.0 ka BP by using the optically stimulated luminescence (OSL) dating method. The period corresponds to the transition period of the Last Deglaciation to the Holocene, corresponds to the Bolling/Aellrod warming event in the Last Deglaciation in Europe and the Greenland ice core. At this time, the phenomenon of glacier ablation was prevalent in the Tibetan Plateau, which may be concluded that the paleoflood events were closely related to glacier ablation in the same basin. These results are of great significance to mitigate flood disasters and to exploit water resources, as well as to understand hydrological response to global climate change.

Key words: paleoflood, Last Deglaciation, optically stimulated luminescence (OSL), climate change, source regions of the Yellow River

中图分类号: 

  • P331.1