Validated sample ages from 823 EPD sites

The number of well-dated pollen diagrams in Europe has increased considerably over the last 30 years and many of them have been submitted to the European Pollen Database (EPD). This allows for the construction of increasingly precise maps of Holocene vegetation change across the continent. Chronological information in the EPD has been expressed in uncalibrated radiocarbon years, and most chronologies to date are based on this time scale. Here we present new chronologies for most of the datasets stored in the EPD based on calibrated radiocarbon years. Age information associated with pollen diagrams is often derived from the pollen stratigraphy itself or from other sedimentological information. We reviewed these chronological tie points and assigned uncertainties to them. The steps taken to generate the new chronologies are described and the rationale for a new classification system for age uncertainties is introduced. The resulting chronologies are fit for most continental-scale questions. They may not provide the best age model for particular sites, but may be viewed as general purpose chronologies. Taxonomic particularities of the data stored in the EPD are explained. An example is given of how the database can be queried to select samples with appropriate age control as well as the suitable taxonomic level to answer a specific research question.

近三十年来，欧洲地区经精确定年的孢粉图（pollen diagrams）数量大幅增长，其中多数已提交至欧洲孢粉数据库（European Pollen Database, EPD）。这为构建覆盖整个欧洲大陆的全新世（Holocene）植被变化高精度分布地图提供了可能。
欧洲孢粉数据库中的年代学信息此前均以未校准放射性碳年代（uncalibrated radiocarbon years）表述，且迄今多数年代序列均基于该时间尺度构建。本文针对该数据库存储的多数数据集，提供了基于校准放射性碳年代（calibrated radiocarbon years）的全新年代序列。
孢粉图对应的年代信息通常源自孢粉地层学本身，或其他沉积学相关资料。我们对这些年代学锚点进行了系统梳理，并为其赋予了不确定性参数。本文详述了生成新年代序列的具体步骤，并介绍了全新的年代不确定性分类系统的设计原理。
最终得到的年代序列可适用于多数大陆尺度的研究问题。尽管其未必能为特定研究站点提供最优的年龄模型，但可作为通用型年代序列使用。
本文还对欧洲孢粉数据库中存储数据的分类学特殊性进行了解释说明，并通过示例演示了如何查询该数据库，以筛选具备合适年代控制条件以及匹配特定研究问题所需分类学层级的样本。