干旱区生态环境知识资源中心(Arid): 河西走廊花海剖面晚冰期以来年代学及沉积特征研究

Arid

	河西走廊花海剖面晚冰期以来年代学及沉积特征研究
其他题名	The Chronology and Characteristics of Sediments Since Late Glacial in Huahai Lake,Hexi Corridor,NW China
	王乃昂; 李卓仑; 李育; 朱金峰
来源期刊	沉积学报
ISSN	1000-0550
出版年	2011
卷号	29 期号:3 页码:552-560
中文摘要	选择位于河西走廊的花海古湖泊沉积剖面作为研究对象,根据13个普通14C和5个AMS14C年代结果,以沉积物岩性特征为主要指标,建立了晚冰期以来花海湖泊沉积的年代框架及环境变化过程。结果表明:花海地区新仙女木期和晚冰期花海湖泊主要以芒硝沉积为主,指示了较低的温度环境。芒硝沉积中的淤泥细线为短暂升温标志,芒硝-淤泥-芒硝的沉积韵律揭示了晚冰期和新仙女木期气候的不稳定性和温度的周期性变化。根据沉积过程和岩性特征,全新世花海湖泊在千年尺度上存在干湿变化特征。10.47 cal ka BP之前的早全新世气候较为干旱,以冲洪积和风成砂为主的沉积过程,10.47～8.87 cal ka BP的早全新世湖相沉积所揭示的气候由干到湿的转变期,8.87～ 5.5 cal ka BP存在深湖相沉积的气候湿润期,5.5 cal ka BP至今沉积间断所揭示的中晚全新世气候呈现干旱化趋势,湖泊趋于萎缩干涸。
英文摘要	From the profile which is located in the Hexi Corridor,NW China.13 samples were collected for conventional~(14)C dating and 5 samples were collected for AMS~(14)C dating.The materials used for~(14)C dating were seeds,mud and wood.Based on the dating results,we reconstructed the age framework of Huahai Lake since the Late Glacial period.And then,we concluded that the sediments between 0.73～6.83 m were deposited during Holocene.Between 6.83～7.35 m,the sediments were deposited during the early Holocene and the late Younger Dryas.The sediments of 7.35～10.44 m were deposited during the Late Glacial and early Younger Dryas.Based on the mineral analysis of the sediments during the Younger Dryas and late glacial,mirabilite was the main component in the sediments,indicating the low-temperature environment.According to the chemical composition analysis,the main ingredient of the pure mirabilite deposition is Na2 SO4·10H2 O,which is an indicator of the cold-dry environment;and the lower the temperature is good for the mineral crystallizing processes.The solubility curve of SO_4~(2-)in Na_2 SO4_-NaCl-H_2O indicated that,in low surrounding temperature,the concentration of SO_4~(2-)was lower in saturation Na2 SO4,and simply increasing the lake level could not improve the ability of mirabilite solution,which was not powerful enough to break off the deposition.The main reason of the interruption for mirabilite deposition may be transient warming events.Therefore,the rhythm deposition formation of mirabilite-silt-mirabilite indicated the periodic changes of temperature during the late glacial and the Younger Dryas.According to the characteristics of the sediments and lithology,we reconstructed the millennium-scale effective moisture conditions during the Holocene period.Before 10.47 cal ka BP,the sediments color appears dark brown,purple brown-based,indicating a typical oxidizing environment,and this oxidative environment can not appear in the deep lake environment.There are no obvious lacustrine depositions layers at the beginning of Holocene(before10.4 cal ka BP),6.30～3.73 m,and instead the layers are formed mainly on alluvial and eolian depositions,while the eolian depositions layers sandwiched between two alluvial depositions layers.The climate was relatively arid,and the alluvial and aeolian sediments prevailed during this period.Between 10.47 cal ka BP and 8.87 cal ka BP,the climate changed from arid to humid.During 8.87～5.5 cal ka BP the lake was relatively deep,and the climate was relatively humid.From 5.5 cal ka BP,there was little sediment in the section,showing that the lake became to dry up since then.This Holocene environmental change in millennium-scale was different from the westerlies in the arid Central Asian areas,but it was not the same as the environmental change in the eastern part of China,which was controlled by Asian monsoon.So the Holocene environment of the Huahai Lake region was affected by the Westerlies and the East Asian monsoon.
中文关键词	晚冰期 ; 新仙女木气修事件 ; 年代学 ; 河西走廊 ; 花海
英文关键词	the Late Glacial Younger Dryas Event chronology Hexi Corridor Huahai Lake
语种	中文
国家	中国
收录类别	CSCD
WOS类目	GEOLOGY
WOS研究方向	Geology
CSCD记录号	CSCD:4225483
来源机构	兰州大学
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/226239
作者单位	兰州大学资源环境学院兰州大学干旱区水循环与水资源研究中心, 兰州, 甘肃 730000, 中国
推荐引用方式 GB/T 7714	王乃昂,李卓仑,李育,等. 河西走廊花海剖面晚冰期以来年代学及沉积特征研究[J]. 兰州大学,2011,29(3):552-560.
APA	王乃昂,李卓仑,李育,&朱金峰.(2011).河西走廊花海剖面晚冰期以来年代学及沉积特征研究.沉积学报,29(3),552-560.
MLA	王乃昂,et al."河西走廊花海剖面晚冰期以来年代学及沉积特征研究".沉积学报 29.3(2011):552-560.