松辽盆地晚三冬期的黑碳记录及其古环境意义

发布时间：2018-05-16 14:16

本文选题：松辽盆地 + 嫩江组　；参考：《地学前缘》2017年01期

【摘要】：黑碳(BC)是生物质和化石燃料等不完全燃烧产生的含碳物质,古老沉积物中的黑碳记录可以重建过去的火灾事件和陆地植被演化历史。文中通过对晚三冬期松辽盆地姚家车站剖面、后金沟剖面和岳王城剖面的黑碳记录进行分析,来揭示嫩江组一段到二段下部的火灾事件、气候特征及植被变化信息。研究结果显示:嫩江组一段BC的含量较低,为0%~0.22%,表明可能存在的火灾事件规模很小;在该段时期有几次BC/TOC值较高,暗示着小规模的火灾事件。在嫩二段下部BC的含量突然升高,最高可达1.4%,反映了大规模火灾事件的发生。黑碳的稳定碳同位素(δ~(13) CBC)数据表明:在嫩一段,黑碳的δ~(13) CBC值(-29.4‰~-25.0‰)表现为逐渐偏正的趋势,可能是由大气CO_2浓度逐渐降低所导致;在嫩二段下部,δ~(13) CBC值先呈现突然偏负的趋势,可能是由于大规模的火灾事件以及火山活动引起的大气CO_2浓度短暂升高以及植被类型的变化所造成的,之后δ~(13) CBC值又表现为逐渐偏正的特征。综合来看,在嫩江组一段仅发生小规模火灾事件,嫩二段下部则发生大规模火灾事件,由嫩江组一段到二段下部大气CO_2浓度呈现降低—升高—再降低的变化趋势。
[Abstract]:Black carbon (BC) is a carbon containing substance produced by incomplete combustion of biomass and fossil fuels. Black carbon records in ancient sediments can reconstruct the past fire events and the history of terrestrial vegetation evolution. In this paper, the black carbon records of the Yao's station section in the late three winter Songliao Basin, the rear Golden Gully section and the Yue Wang City section were analyzed to reveal the black carbon record. The fire events, climate characteristics and vegetation change information in the lower part of the Nenjiang group to the lower part of the Nenjiang group. The results showed that the level of BC in the first section of the Nenjiang group was low, 0%~0.22%, indicating that the possible scale of the fire incident was small; in this period, a few times of BC/TOC were higher, suggesting a small scale of fire events. The content of BC in the lower part of the tender section was sudden. The increase is up to 1.4%, reflecting the occurrence of large-scale fire events. The stable carbon isotopes of black carbon (delta ~ (13) CBC) data show that the delta ~ (13) CBC value (-29.4% ~-25.0 per thousand) of black carbon shows a trend of gradual deviation in the tender section, which may be caused by the gradual decrease of CO_2 concentration in the atmosphere; at the lower part of the tender two section, the value of delta ~ (13) CBC appears first. However, the tendency to be negative may be caused by large-scale fire events and the transient increase of atmospheric CO_2 concentration caused by volcanic activity and changes in the type of vegetation, and then the value of delta ~ (13) CBC is characterized by gradual deviation. The CO_2 concentration of the lower part of the Nenjiang section shows a trend of decreasing - rising - decreasing again from the first to the two paragraph of the model fire.

【作者单位】：中国科学院广州地球化学研究所有机地球化学国家重点实验室;中国科学院大学;中国地质大学生物地质与环境地质国家重点实验室;
【基金】：国家重点基础研究发展计划“973”项目(2012CB822002) 国家自然科学基金项目(41473104,41302008,41321002)
【分类号】：P532;P534.53

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