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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。
Central Tibet is a key area for westerly-monsoon interaction and is extremely sensitive to climate change. Taking the sedimentary section of T1 terrace in the northwestern part of Yogyakarta as the research object, the age scale was established by using optical-luminescence dating. By analyzing the proxy index of sediment grain size, TOC and TN, Paleoclimate changes since the world to study. The results show that the T1 stage represents the lacustrine deposits during the period of about 6 ka BP to 1.4 ka BP, and the two major climatic stages of the middle and late Holocene in this area are recorded. Stage I (during the period of about 6 ka BP to 3.4 ka BP) was warm and humid with high and stable lake water level. Stage II (about 3.4 ka BP ~ 1.4 ka BP) developed towards dry-cold direction, and the water level dropped obviously. ka BP to reach the lowest level. The correlation between the climate change and the lacustrine deposits in the surrounding areas since the mid-late Holocene of the Yogyakarta fault revealed by the profile shows that the variation of humidity in this area is more obvious by the monsoon, which provides evidence for the scope of the monsoon on the plateau.