High-latitude Lake Basal Ages and Origins - link to datafile

This dataset is a compilation of 1,207 lake basal ages used to identify spatial and temporal patterns of lake formation across the high northern latitudes. Data was gathered from scientific literature descriptions of lake cores, peat cores underlain by lake sediments, and exposures within the domain of glaciation and permafrost extent during the Last Glacial Maximum. We distinguished eight classes of lake origin. Where not indicated by the author, we sought to determine lake origin from lithology, geological history and site descriptions within the text. Though most records (95%) were radiocarbon dated, we included robust dates obtained by a variety of methods including varve counting, photoluminescence, Pb/Cs, Th/U, wiggle matching and tephrochronology. We reported oldest sample ages in the majority of cases, electing not to utilize basal ages derived from age-depth models extrapolated beyond dated levels due to both their high level of uncertainty and differences between methodologies used to construct each model. We excluded dates from shallow lake cores that clearly did not reach basal lake sediments, or that were collected for the sole purpose of methods development or recent human impact studies. Records that did not include dates from lower-most cored sediments, that suffered from uncorrected reservoir effects (noted by original author) or that contained copious age reversals were also excluded. Some records provided distinct stratigraphic evidence of lake formation that allowed for exact determination of lake basal age, while other lithologies were more ambiguous. To address this uncertainty, we categorized each lake age as "minimum" or "basal" based on interpretation of contextual, geographical and lithological information.

本数据集收录了1207组湖泊基底年代数据，用于识别北高纬度区域内湖泊形成的空间与时间分布模式。本数据集的数据采集自科学文献中关于湖泊岩芯、覆有湖泊沉积物的泥炭岩芯，以及末次冰盛期（Last Glacial Maximum）冰川作用与多年冻土分布范围内露头剖面的相关描述。研究团队区分了八类湖泊成因类型。若原始文献作者未明确标注湖泊成因，我们将依据岩性、地质历史及文本中的采样点位描述来推断湖泊成因。尽管95%的记录采用放射性碳测年（radiocarbon dating），但我们也纳入了通过多种可靠方法获得的年代数据，包括纹泥计数（varve counting）、光致发光测年（photoluminescence）、Pb/Cs测年、Th/U测年、wiggle匹配定年（wiggle matching）及火山灰年代学（tephrochronology）。多数情况下我们采用样本的最老年代数据，未使用通过年龄-深度模型（age-depth models）外推至测年层位之外得到的基底年代，原因在于此类外推结果不确定性较高，且不同模型构建方法间存在显著差异。我们剔除了未钻穿湖泊基底沉积物的浅湖岩芯测年数据，以及仅为开发测年方法或研究近期人类影响而采集的岩芯测年数据。未获取岩芯最底部沉积物年代数据、存在未校正的储层效应（reservoir effects，原始文献作者已标注）或存在大量年代倒转的记录也被排除。部分记录提供了明确的地层学证据以证明湖泊形成过程，可精确确定湖泊基底年代；而部分岩性记录则较为模糊。为应对这一不确定性，我们结合背景信息、地理信息与岩性资料，将每个湖泊年代划分为最小年代（minimum）或基底年代（basal）两类。