Data from: "Using legacy data to reconstruct the past? Rescue, rigor and reuse in peatland geochronology"

There is a growing interest for rescue and reuse of data from past studies (so-called legacy data). Data loss is alarming, especially where natural archives are under threat, such as peat deposits. Here we develop a workflow for reuse of legacy radiocarbon dates in peatland studies, including a rigorous quality assessment that can be tailored to specific research questions and study regions. A penalty score is assigned to each date based on criteria that consider taphonomic quality (i.e. sample provenance) and dating quality (i.e. sample material and method used). The weights of quality criteria may be adjusted based on the research focus, and resulting confidence levels may be used in further analyses to ensure robustness of conclusions. We apply the proposed approach to a case study of a (former) peat landscape in the northern Netherlands, aiming to reconstruct the timing of peat initiation spatially. Our search yielded 313 radiocarbon dates from the 1950s to 2019. Based on the quality assessment the dates—of highly diverse quality—were assigned to four confidence levels. Results indicate that peat initiation for the study area first peaked in the Late Glacial, dropped during the Boreal (10640 – 9220 cal y BP) and showed a second peak in the Subboreal (5660 – 2400 cal y BP). Further spatial analysis shows that for local valleys peat initiation occurred throughout the Holocene, with age-elevation plots indicating a prominent control by Holocene sea level rise. On plains and ridges peat initiation only occurred during the Subboreal, likely controlled by groundwater rise related to sea level rise. Our study highlights the potential of legacy data for palaeogeographic reconstructions, as it is cost-efficient and provides access to information no longer available in the field. However, data retrieval may be challenging and reuse of data requires that basic information on location, elevation, stratigraphy, sample and analysis details are documented irrespective of the original research aims.<br>

学界对过往研究数据（即所谓遗留数据（legacy data））的抢救与复用需求日益增长。数据流失问题令人担忧，在泥炭沉积这类自然档案面临威胁的场景下尤为突出。为此，我们开发了一套适用于泥炭地研究中遗留放射性碳定年数据（radiocarbon dates）复用的工作流程，其中包含可针对特定研究问题与研究区域定制的严格质量评估体系。我们基于综合考量埋藏学质量（taphonomic quality，即样品来源）与定年质量（dating quality，即样品材质与所用方法）的评判标准，为每条定年数据分配惩罚分值。质量评判标准的权重可根据研究重点进行调整，所得的置信等级可用于后续分析，以确保研究结论的稳健性。我们将所提出的方法应用于荷兰北部一处（原）泥炭地貌的案例研究，旨在重建泥炭起始发育时间的空间分布格局。本次文献检索共获取了1950年至2019年间的313条放射性碳定年数据。经质量评估后，这批质量差异悬殊的定年数据被划分为四个置信等级。结果显示，研究区的泥炭起始发育率先在晚冰期（Late Glacial）达到峰值，在北方期（Boreal，10640–9220 cal y BP）出现回落，并在亚北方期（Subboreal，5660–2400 cal y BP）迎来第二次峰值。进一步的空间分析表明，区域河谷内的泥炭起始发育贯穿全新世（Holocene），年龄-海拔分布图（age-elevation plots）显示全新世海平面上升对其存在显著控制作用。而平原与脊状地貌区的泥炭仅在亚北方期开始发育，这一现象大概率受海平面上升引发的地下水位上升控制。本研究凸显了遗留数据在古地理重建（palaeogeographic reconstructions）中的应用潜力，因其兼具成本效益优势，并可获取野外已无法再采集的相关信息。但数据检索仍存在诸多挑战，且复用数据时，无论原始研究目标如何，均需完整记录采样地点、海拔、地层学（stratigraphy）信息、样品详情与分析细节等基础资料。