晚冰期以来大柴旦盐湖沉积记录的古气候演变及其尘暴事件

Paleoclimatic Evolution and Dust Storm Event Recorded by Muddy Silt from Sediment Profile DCD03 of Da Qaidam Salt Lake in the Northern Qaidam Basin since Late Glacial Period 

中文关键词:  大柴旦盐湖  湖底沉积剖面  晚冰期  古气候演化  尘暴事件

英文关键词:Da Qaidam Salt Lake  Subbottom sediment profile  Late Glacial period  Paleoclimatic evolution  Dust storm event

中文摘要:

      选择大柴旦盐湖DCD03沉积剖面柱硼镁石矿层下伏土黄色淤泥质粉砂层为研究对象,基于AMS ¹⁴C年代学、岩性地层学、矿物学以及地球化学等研究方法,旨在探讨土黄色湖相淤泥质粉砂沉积记录的尘暴事件,以及重建晚冰期以来西风环流显著影响区的水文气候变化。研究结果表明,DCD03沉积剖面的淤泥质粉砂样品粒度频率曲线呈现为双峰态,主峰(均值10 μm)反映了河流作用携带入湖的细粒组分,次峰(＞32 μm)则反映了风力作用以及河流作用等携带入湖的粗粉砂粒组分。大于64 μm的砂砾组分可能代表外源风尘物质的输入,由尘暴天气携带入湖。大柴旦地区晚冰期以来依次出现了博令和阿勒罗德暖期(12.94~12.17 cal.ka BP)、新仙女木冷期(12.17~11.37 cal.ka BP)、不稳定的早全新世气候(11.37~8.64 cal.ka BP)以及趋于偏冷干的中全新世早期(8.64~7.39 cal.ka BP)。

英文摘要:

      The paper focused on the study of muddy silt from sediment profile DCD03 of Da Qaidam Salt Lake,based on AMS ¹⁴C chronologic,lithostratigraphic,mineralogical and geochemical methods,aimed to discuss the dust storm event recorded by earthy yellow muddy silt,and reconstruct the hydro-climate changes of Da Qaidam region since Late Glacial period.The results showed that the grain-size distribution curve appeared double kurtosis,the main peak (10 μm) reflected fine-grained component by fluvial action,and the secondary peak (＞32 μm) reflected coarse-grained component by aeolian and fluvial action.The gravel component(＞64 μm)may record the dust storm event.Da Qaidam region underwent Blling/Allerd warm period (12.94-12.17 cal.ka BP),Younger Dryas cold period (12.17-11.37 cal.ka BP),unstable early Holocene period (11.37-8.64 cal.ka BP) and relatively cold-dry early mid-Holocene period (8.64-7.39 cal.ka BP) in sequence since Late Glacial period.