Environmental change inferred from granular size character of lacustrine sediment in Inner Mongolia Huangqihai,during 8.0～2.2 ka BP
Environmental change inferred from granular size character of lacustrine sediment in Inner Mongolia Huangqihai,during 8.0～2.2 ka BP
复制标题
DOI：
--
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Shen Hong-yuan
中科院分区：
文献类型：
--
作者：
Shen Hong-yuan
黄旗海位于东亚夏季风的北方界和亚洲冬季风的中心地带，是一个封闭的小型湖泊，其湖泊沉积物敏感地记录了东亚夏季风和亚洲冬季风的气候变化。本文研究了古湖水位记录、沉积环境演变记录和冬季风变化记录，结合13δ记录，（Shen et al，2005），H3剖面的粒度特征和沉积地层学证据表明：（1）8.0- 5.5kaBP之间湖平面处于高水位阶段，这表明夏季风暖湿的古气候增强，冬季风减弱，对应于所谓的全新世岩浆热期。由两个季风环流组成的气候系统远离稳定状态，出现了气团、沙尘沉降和低湖水位7.0- 5.5kaBP期间，冬季风增强和河流作用分别发生了两次事件，其大小区间分别为6.25±0.25 Φ、7.25 ±0.25 Φ、-0.75 ±0.25 Φ和-0.25 ±0.25 Φ;（2）5.1kaBP ~ 3.6kaBP，即所谓的新冰川期，出现了越来越多的气团尘埃沉降，湖平面逐渐下降，这表明在3.6kaBP ~ 2.2kaBP期间，夏季风环流减弱，冬季风增强，气候变冷变干。
Huangqihai,a small enclosed lake in Inner Mongolia of China,lies at the northern boundary of Eastern Asian Summer Monsoon and in the center area of Asian Winter Monsoon,thus its lacustrine sediment sensitively recorded the climate change of the above two monsoon systems.Based on the granular size character of sediment from profile H3 on the northern lacustrine bottomland 13m above the Huangqihai lake surface in 1986,the paper investigates the record of palaeolake water level,sedimentary environment evolution,and winter monsoon change.Together with the 13δ record(Shen et al,2005),the granular size character and sediment stratigraphic evidence of profile H3 suggested that(1)the lake level was at a high stage between 8.0-5.5 ka BP,which indicating that the palaeoclimate that was warm and humid for the summer monsoon was intensified,and the winter monsoon subdued,corresponding to the so-called Holocene Magathermal.However,the climate system made up of the two monsoon circulations far from the stable state for there appeared air mass dust sedimentation and low lake level events in twice during the 7.0-5.5 ka BP for abruptly-reinforced winter monsoon and fluvial effect inferred from the increased proportion of 6.25±0.25 Φ,7.25±0.25 Φ,-0.75±0.25 Φ,and-0.25±0.25 Φ size interval respectively;(2)during 5.1 ka BP～3.6 ka BP,timed to the so-called new-glacier,there appeared more and more air mass dust sedimentation and the lake level gradually decreased,which showed a cooler and drier climate for summer monsoon circulation was weakened and winter monsoon enhanced on the contrary.this kind of condition was persisted in during 3.6 ka BP～2.2 ka BP.