新疆伊犁晚全新世风成沙—古土壤序列磁化率特征及气候变化
摘要: 选择新疆伊犁河谷塔克尔莫乎尔沙漠古风成沙—古土壤沉积剖面为研究对象，通过73块样品的磁化率及其与TOC、CaCO3、Fe2O3和粒度组成的相关分析，并以OSL测年为时间标尺，讨论剖面沉积的磁化率变化机制及其古气候意义。结果表明：剖面低频磁化率（χlf）与16～250 μm百分含量为正相关，即低频磁化率χlf变化主要受粗组分含量变化的影响。其中，古风成沙χlf值多高于古土壤，这与我国季风区沙漠沉积的磁化率变化特征相反。根据剖面磁化率及各种环境指标综合分析，研究区3.7 kaBP以来的气候变化可划分为5个阶段：3.71～3.06 kaBP凉湿、3.06～2.78 kaBP冷干、2.78～2.10 kaBP凉湿、2.10～0.50 kaBP冷湿、0.50～0.00 kaBP温干。晚全新世气候变化与周边地区古气候记录有较好的一致性，并与同期北大西洋表层海温变化事件呈现很好的遥相关,总体上表现为相对暖干、凉湿的典型西风气候变化模式。
Late Holocene Climate Change Revealed by the Magnetic Susceptibility of Paleoaeolian SandPaleosol Sedimentary Sequence in Yili Valley of Xinjiang
Abstract: By studying on correlation between magnetic susceptibility,TOC,CaCO3,Fe2O3 and grainsize component of 73 samples from the paleosandpaleosol sedimentary section of Xinjiang Takermohuer desert,according to OSL date,we discussed mechanism of magnetic susceptibility change and paleoclimate significance.The results were that:The correlation between χlf and percent content of 16~250 μm component was positive,coarse component percent content affected the change of χlf.In the section, χlf of paleosand is higher than χlf of paleosol,this characteristic is opposite to magnetic susceptibility of monsoon desert sediment in China.According to magnetic susceptibility and other paleoclimate indexes of section sediment,we divided 5 paleoclimate stages of study area from 3.71 ka BP:3.71~3.06 kaBP,the climate was cool and wet,from 3.06 kaBP to 2.78 kaBP was cold and dry,2.78~2.10 kaBP was cool wet,2.10~0.50 kaBP was cold and wet,0.50 kaBP to now was warm and dry.Climate change of research area is simliar to the other regiones during late holocene,and it was related to the temperature change events of surface seawater in north Alantic Ocean.The climate change was typical westerly climate model,warmdry or coolwet.
新疆伊犁晚全新世风成沙—古土壤序列磁化率特征及气候变化[J]. 沉积学报, 2012, 30(5): 928-936.
| 引用本文: |
新疆伊犁晚全新世风成沙—古土壤序列磁化率特征及气候变化[J]. 沉积学报, 2012, 30(5): 928-936.
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Late Holocene Climate Change Revealed by the Magnetic Susceptibility of Paleoaeolian SandPaleosol Sedimentary Sequence in Yili Valley of Xinjiang[J]. Acta Sedimentologica Sinica, 2012, 30(5): 928-936.
| Citation: |
Late Holocene Climate Change Revealed by the Magnetic Susceptibility of Paleoaeolian SandPaleosol Sedimentary Sequence in Yili Valley of Xinjiang[J]. Acta Sedimentologica Sinica, 2012, 30(5): 928-936.
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