西藏中部当惹雍错湖泊阶地记录的中晚全新世古气候变化

发布时间：2018-04-09 01:27

本文选题：当惹雍错　切入点：湖泊阶地　出处：《地理研究》2017年06期

【摘要】：西藏中部是西风与季风相互作用的关键区域,对气候变化响应极为敏感。以该区域当惹雍错西北部T1阶地的沉积剖面为研究对象,利用光释光测年确立年代标尺,通过沉积物粒度、TOC、TN等代用指标分析,对当惹雍错地区中晚全新世以来的古气候变化进行研究。结果显示,T1阶地代表了约6 ka BP~1.4 ka BP期间的湖相沉积;记录了该区域中晚全新世的两个主要气候阶段。阶段I(约6 ka BP~3.4 ka BP期间)气候温暖湿润,湖泊水位较高且稳定;阶段II(约3.4 ka BP~1.4 ka BP)气候朝着干冷方向发展,水位下降明显,并在2.4 ka BP左右达到最低水位。通过该剖面揭示的当惹雍错中晚全新世以来的气候变化与周边区域的湖泊沉积记录进行对比,表明该地区湿度变化受季风影响较为明显;为季风在高原上的作用范围提供了证据。
[Abstract]:Central Tibet is a key area for the interaction between the westerly and the monsoon, and is extremely sensitive to the response to climate change.Taking the sedimentary profile of T1 terrace in the northwest of Dangyazhiyakia as the object of study, the age scale is established by means of optical luminescence dating, and the proxy indexes such as TOC TN are analyzed by means of sediment granularity.The paleoclimate change since the middle and late Holocene in Dangyakiyangcao area was studied.The results show that the T 1 terrace represents the lacustrine deposits during the period of about 6 ka BP~1.4 ka BP, and records the two main climatic stages of the Middle and late Holocene in the region.The climate of stage I (about 6 ka BP~3.4 ka BP) is warm and humid, the water level of the lake is high and stable, and the climate of stage II (about 3.4 ka BP~1.4 ka BP) develops towards the direction of dry and cold, the water level decreases obviously, and reaches the lowest level at about 2.4 ka BP.The comparison between the climate change since the middle and late Holocene and the lake sediment records in the surrounding area shows that the humidity change in this area is obviously affected by the monsoon.It provides evidence for the range of monsoon action on the plateau.
【作者单位】：中国地质大学(武汉)地球科学学院;中国地质大学(武汉)生物地质与环境地质国家重点实验室;中国科学院青藏高原研究所青藏高原环境变化与地表过程重点实验室;
【基金】：国家自然科学基金项目(41102070,41330103,41271225)
【分类号】：P532

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