典型人为有机质记录反演西藏地区近代湖泊沉积环境演变

Anthropogenic organic matters can be used as environmental proxies to indicate the evolution of sedimentary environment and the influence degree of human activities on it, in which persistent organic pollutions (POPs) are typical anthropogenic organic matters. In order to reveal the influence of human activities on the evolution of sedimentary environment in Tibetan Plateau, it is significant to study POPs recorded in sediments of lakes. ‘Anthropocene’ is a new geological epoch in which human acitivities is considered as a dominant factor. The study on the evolution sedimentary environment of lakes in Tibetan Plateau will help to investigate sedimentary signature associated with the time division of Anthropocene, so it is greatly significant to do that. In this project, sedimentary cores will be sampled in Yamdark Co. and Siling Co. in Tibet, and the high-resolution dating for cores will be performed by the method of 210Pb/137Cs. Furthermore, the composition and the concentration of optimally selected POPs in sediments will be analyzed. Based on it, POPs will be used as environmental proxies to resume the evolution of sedimentary environment, to divide the time section of the evolution, to trace the resources by the fingerprint of POPs, and then to illuminate the influence degree of human activities on the sedimentary environment. At the same time, POPs will first be used as anthropogenic signature to study the response of sedimentary records to the human activities, and to investigate the signature sedimentary layer associated with human activities. This study will provide an important sedimentological basis for the further discussion of regional environmental evolution and the influence of human activities on it, and will also provide an important foundation to reveal the time division of the Anthropocene and its criteria, which will provide a reference for global comparison.

人为有机质可作为环境指标指示沉积环境演变及人类活动影响程度，其中持久性有机污染物(POPs)为典型人为有机质。为揭示人类活动对青藏高原沉积环境演变的影响，开展高原湖泊沉积记录POPs相关研究具有重要意义。“人类世”是一个新的以人类活动为主导的地质时期，高原湖泊沉积环境演化研究，有助于探寻与其年代划分相关的沉积标志，其意义重大。立项在西藏羊卓雍错和色林错采集沉积柱，采用210Pb/137Cs方法开展高分辨定年，并分析沉积记录中优选POPs的组分与含量。在此基础上，以POPs为环境指标，反演沉积环境演变过程，划分演化阶段，依其指纹特征示踪物质来源，阐明人类活动的影响程度；同时，首次以POPs为人类活动标志物，研究沉积记录对人类活动的响应，探寻与人类活动相关的沉积标志层。研究为深入探讨区域环境演变与人类活动影响提供重要的沉积学依据，为揭示人类世的年代划分及标准奠定重要基础，为全球对比提供参照。

通过收集了3类POPs的69套数据，分析数据的时间趋势，重建其沉积记录，揭示 20世纪40-60年代间不同类型POPs变化特征，发现多环芳烃（PAHs）和多氯联苯（PCBs）可以作为潜在的标志物指示沉积物中化学地层的界限。通过高原湖泊沉积柱记录POPs研究发现，随全球变暖PAHs的含量和轻组分比例都呈下降趋势，揭示了大气沉降过程中POPs的分馏特征。湖泊沉积柱对比研究显示，虽然高原地区本地源释放一定量的POPs，但对高原地区背景值或整体影响有限，高原地区POPs主要来源于长距离大气迁移（LRAT）。通过粒径分选研究发现，粒径较小的颗粒物对POPs的吸附能力最强，同时不同粒径颗粒物吸附POPs的迁移能力也不同。上述研究成果为深入理解全球变暖背景下POPs的全球循环机制提供科学依据，为探讨人类世地层下限时间提供可指示性标志化合物。在基金资助下发表SCI论文9篇，中文核心论文1篇。