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| 18.5kaB.P.以来东北四海龙湾玛珥湖全岩有机碳同位素记录及其古气候环境意义 | |
| 引用本文： | 刘强,刘嘉麒,陈晓雨,游海涛,储国强,汉景泰,J.Mingram,G.Schettler,J.F.W.Negendank.18.5kaB.P.以来东北四海龙湾玛珥湖全岩有机碳同位素记录及其古气候环境意义[J].第四纪研究,2005,25(6):711-721. |
| 作者姓名： | 刘强 刘嘉麒 陈晓雨 游海涛 储国强 汉景泰 J.Mingram G.Schettler J.F.W.Negendank |
| 作者单位： | 1. 中国科学院地质与地球物理研究所,北京,100029 2. 中国科学院地质与地球物理研究所,北京,100029;吉林大学地球科学学院,长春,130061 3. GeoForschungsZentrum Potsdam,D-14473 Potsdam,Germany |
| 基金项目： | 科技部科研项目;国家自然科学基金;中国科学院知识创新工程项目 |
| 摘 要： | 结合含水量、TOC含量和TOC/TN比值变化曲线,18·5kaB·P·以来的四海龙湾玛珥湖沉积物全岩有机碳同位素组成（δ13CTOC）记录可划分为3个阶段:1)末次冰期晚期（18·5～14·7kaB·P·）,δ13CTOC值偏正,变化范围为-29·50‰～-26·18‰,平均值约为-28·10‰;2)末次冰消期（14·7～11·7kaB·P·）,δ13CTOC值显著偏负,变化范围为-33·92‰～-28·40‰,平均值约为-31·75‰,在δ13CTOC值变化曲线上表现为一个低谷,但在类似YoungerDryas的冷干事件期间（12·7～11·7kaB·P·）,δ13CTOC值再次显著偏正,最高可达-28·4‰;3)全新世以来（11·7kaB·P.至今）,δ13CTOC值变化幅度不大（-30·85‰～-27·37‰）,基本上都在平均值-29·1‰左右。研究表明,大气CO2浓度变化是影响18·5kaB·P·以来四海龙湾玛珥湖δ13CTOC值变化的主导因素。 |
| 关 键 词： | 四海龙湾玛珥湖 全岩有机碳同位素 末次冰消期 全新世 大气CO2浓度 |
| 文章编号： | 1001-7410（2005）06-711-11 |
| 收稿时间： | 2005-04-22 |
| 修稿时间： | 2005-06-10 |
STABLE CARBON ISOTOPE RECORD OF BULK ORGANIC MATTER FROM THE SIHAILONGWAN MAAR LAKE, NORTHEAST CHINA DURING THE PAST 18.5ka |
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| Liu Qiang,Liu Jiaqi,Chen Xiaoyu,You Haitao,Chu Guoqiang,Han Jingtai,J.Mingram,G.Schettler,J.F.W.Negendank.STABLE CARBON ISOTOPE RECORD OF BULK ORGANIC MATTER FROM THE SIHAILONGWAN MAAR LAKE, NORTHEAST CHINA DURING THE PAST 18.5ka[J].Quaternary Sciences,2005,25(6):711-721. | |
| Authors: | Liu Qiang Liu Jiaqi Chen Xiaoyu You Haitao Chu Guoqiang Han Jingtai JMingram GSchettler JFWNegendank |
| Institution: | 1.Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029; 2. College of Earth Sciences, Jilin University, Changchun 130061 ; 3.GeoForschungsZentrum Potsdam, D-14473 Potsdam, Germany |
| Abstract: | Sihailongwan Maar Lake is one of the eight Maar lakes in Longgang Volcanic Field, Northeast China. Three Sino-Germany cooperational drilling campaigns were conducted from August 1998 to July 2001, and three composite profiles of lake sediments have been constructed. Correlated with analytic results of water contents, TOC concentrations and TOC/TN ratios of composite profile Ⅱ, the stable carbon isotope record of bulk organic matter （δ13CTOC） can be divided into three stages during the past 18.5ka: （1） the late stage of the Last Glacial （18.5～14.7kaB.P.）. The δ13CTOC values were less negative, within the range of -29.50‰～-26.18‰ and with the average of -28.10‰. （2） the last deglaciation （14.7～11.7kaB.P.）. The δ13CTOC values became much more negative, which changed from -33.92‰ to -28.40‰, with the average of -31.75‰. There generally appears a valley on the δ13CTOC curve, with the exception that during the period of a Younger Dryas-like cold event （12.7～11.7kaB.P.）, the δ13CTOC values reach a peak of -28.4‰. （3） the Holocene （11.7kaB.P.～present）. The δ13CTOC values remained relatively stable （-30.85‰～-27.37‰） around the average of -29.1‰. The organic matter of lake sediment deposited during the late stage of the Last Glacial （18.5～14.7kaB.P.） consists mainly of aquatic phytoplankton with low primary productivity, which reflects a cold and dry paleoenvironment. Because of the lower atmospheric CO2 concentration during this period, the dissolved CO2 concentration in lake water was also lower. Consequently, the photosynthesis of phytoplankton using HCO-3 as part of its carbon source resulted in less negative δ13CTOC values. During the last deglaciation （14.7～11.7kaB.P.）, phytoplankton was still the main source for the organic matter in lake sediment despite an increasing contribution from land-derived organic matter during the Blling-Allerd warm interval. Because of the largely increased atmospheric CO2 concentration during the last deglaciation, the dissolved CO2 concentration in lake water increased to an enough level to meet the need of the dissolved CO2 as the main carbon source for photosynthesis of phytoplankton, which resulted in a negative shift of δ13CTOC values. In the record of Sihailongwan Maar Lake, the Holocene started from 11.7kaB.P. Corresponding to climatic amelioration, primary productivity of land and aquatic plants increased evidently during the Holocene. Land-derived organic matter became the major contribution to lake sediment, although aquatic phytoplankton still played an important role. Because of the relatively stable atmospheric CO2 concentration during the Holocene, the δ13C values of aquatic phytoplankton changed little. Similarly, the variation range of δ13C values of land plants is limited, probably revealing the characteristic δ13C values of C3 plants. The relatively stable δ13CTOC values during the Holocene should be the integration of these two factors. Based on comprehensive research, it can be concluded that the change of atmospheric CO2 concentration is the control factor to the variation of δ13CTOC values of the Sihailongwan Maar Lake during the past 18.5ka. |
| Keywords: | Sihailongwan Maar Lake organic carbon isotope the last deglaciation the Holocene atmospheric CO_2 concentration |
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