有机质饱和烃和δ^(13)C_(org.)记录的博斯腾湖早全新世晚期以来生态环境演变  

ECOLOGICAL ENVIRONMENT CHANGE RECORDED BY SEDIMENT n-ALKANE ANDδ^(13)C_(org).OF LAKE BOSTEN SINCE LATE OF EARLY HOLOCENE

作　　者：任雅琴[1] 王彩红[1] 李瑞博[1] 张惠荣[1] 张成君[2] 

机构地区：[1]兰州大学资源环境学院环境科学研究所,兰州730000 [2]兰州大学地质科学与矿产资源学院甘肃省地质矿产重点实验室,兰州730000

出　　处：《第四纪研究》2014年第2期425-433,共9页Quaternary Sciences

基　　金：国家自然科学基金面上项目(批准号:41173015);教育部博士点基金项目(批准号:20100211110020)共同资助

摘　　要：通过对新疆博斯腾湖湖芯沉积物中有机质饱和烃、有机质碳同位素组成(δ^(13)C_(crg))以及与前人得到的环境代用指标结果综合分析,重建了博斯腾湖从早全新世晚期以来古生态环境和湖泊水文的变化历史。结果表明,博斯腾湖大约在8130cal.a B.P.之前气候冷湿,湖泊不发育;约在8130~6400cal.a B.P.为暖湿的全新世适宜期,博斯腾湖流域降水和开都河径流量增加,湖泊水位上升外溢,水生植物及陆生植物发育;6400~5500cal.a B.P.左右冷湿,有效湿度较高,湖泊仍处于较高水位;5500~3000cal.a B.P.左右气候波动明显,为温干时期,而大约在4500—3900cal.a B.P.期间降温,为冷干环境;3000cal.a B.P.以来气温降低,2300~1250cal.a B.P.左右气温有所回升,大约自1250cal.a B.P.以来博斯腾湖地区自然环境逐渐干旱恶化,陆生植物发育较差,而湖泊中沉水植物发育较好。Lake Bosten （41°56′～42°14′N,86°40′ ～87°26′E） is located in Xinjiang Province,Northwest China.In order to reconstruct changes of palaeoecological environment and hydrological characteristics of Lake Bosten since late of Early Holocene,a 9.53m-long core （41°56′33″N,86°45′52″E） called BOST2000 was obtained during a drill in 2000 from the lake using Wright piston drill.The whole core was divided into 467 samples based on an interval of 2cm.The chronology was established according to 14C-AMS data of four grass seeds and five leaves from BOST2000 and XBWu46,extending back to about 8500ca1.a B.P.The paper launched a investigation from 900cm to 0cm of the core which covered approximately from 8300cal.a B.P.to present.The total samples were analyzed for grain size.n-alkanes were analyzed using 8 samples which derived from 26～38cm,160～168cm,336～344cm,446～454cm,560～568cm,710～718cm,820～826cm,and 890～895cm.As the data of stable carbon isotope of bulk sediment organic matter （δ^13Corg） were deficient from 900cm to 950cm,we mainly discussed about 0～ 900cm which contained 439 samples.The data indicated that δ^13Corgranged from-30‰ to-20‰.The distribution of n-alkanes was also discussed in the paper,which showed the relative content of higher molecular weight n-alkanes and middle molecular weight n-alkanes were comparatively higher.The δ^13Corgand n-alkanes records of BOST2000 core showed five stages：（1） Before 8130cal.a B.P.δ^13Corgwas relatively light,higher molecular weight n-alkanes （C27,C29,and C31） which represented woody plants and middle molecular weight n-alkanes （C21 ～ C25） which represented aquatic plants were comparatively higher and dominated by higher molecular weight n-alkanes,which indicated that stage was cold and humid ; （2） During 8130～ 6400cal.a B.P.δ^13Corgfluctuated frequently between-28‰ ～-23‰.n-alkanes （C21 ～ C25） was dominated,which reflected the source of the organic matter was a mixture of terrestrial plan

关 键 词：博斯腾湖 有机质饱和烃 δ^13Corg C N 古生态环境 

分 类 号：P534.632[天文地球—第四纪地质学] P597[天文地球—古生物学与地层学]