Flow cytometry method for purification of fossil pollen from Lake Van varved sediments for AMS radiocarbon dating – a new approach

流式细胞术方法从范湖沉积物中纯化花粉化石进行 AMS 放射性碳测年——一种新方法

• 批准号: 398743521
• 负责人: Dr. Nadine Pickarski
• 金额: --
• 依托单位: Geologischer Dienst Nordrhein-Westfalen Landesbetrieb
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/398743521?language=en
• 关键词: Flow; cytometry; method; purification; fossil

Producing precise and robust geochronological frameworks for reconstructing climatic and environmental changes is a challenge. In this respect, the Lake Van record from Turkey drilled during an ICDP campaign in 2010 has an extraordinary potential caused by the preservation of annually laminated sediments which can be used for a varve chronology in combination with radiocarbon dating. Pollen grains can be used for AMS radiocarbon measurements especially in lake sediments, where little or no terrestrial plant macrofossils are present (such as in Lake Van). Therefore, it is essential when the obtained material is of sufficient purity and concentration. Current methods of extracting fossil pollen all have significant drawbacks regarding the trade-off between effort and abundance as well as purity of fossil pollen in the samples to be prepared for radiocarbon dating. In the proposed research project presented here, we will apply a novel and innovative method enabling rapid purification of fossil pollen for AMS radiocarbon dating based on flow cytometry after Tennant et al. (2013). This method has neither been used so far for establishing a systematic time frame of a sedimentary record nor for improving a continuous varve chronology. We have tested the method as preliminary work based on Lake Van samples. The successful combination of the recent development in AMS technique, i.e., downscaling of sample amount needed for 14C analysis and purification pollen by flow cytometry, led to a dating result within the range of expectation based on varve counting. Based on a cross check between varve counting and 14C measurements, we will produce for the first time a robust calendar-year time scale for the Lake Van record encompassing the last ca 14,000 years. This is a precondition for high-resolution pollen analyses to identify remarkable periods of abrupt and extreme climate change during this time interval.

为重建气候和环境变化而生产精确而健壮的年代学框架是一个挑战。在这方面，在2010年ICDP运动中钻探的土耳其湖唱片的记录具有由保存每年层压的沉积物的非凡潜力，该沉积物可与放射性碳年代结合使用，可用于Varve年代。花粉颗粒可用于AMS放射性碳测量结果，尤其是在湖泊沉积物中，那里很少或没有陆地植物大化石（例如在湖范围内）。因此，当获得的材料具有足够的纯度和浓度时，至关重要。当前提取化石花粉的方法都在努力和丰度之间的权衡以及在放射性碳年代的样品中的纯度以及化石花粉的纯度都有显着的缺点。在此处介绍的拟议的研究项目中，我们将采用一种新颖的创新方法，可以基于Tennant等人的流式细胞仪对化石花粉的快速纯化。 （2013）。到目前为止，该方法既未用于建立沉积记录的系统时间框架，也没有用于改善连续的杂物年表。我们已经根据湖货车样品测试了该方法作为初步工作。最新开发在AMS技术中的成功组合，即，通过流式细胞仪进行14C分析和纯化花粉所需的样本量的缩小，导致基于VARVE计数的预期范围内的约会结果。基于Varve计数和14C测量之间的交叉检查，我们将首次生产出良好的日历年度尺度，用于湖货车记录，其中包含最后一个CA 14,000年。这是高分辨率花粉分析的先决条件，以识别此时间间隔的显着气候变化时期。