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首页> 外文期刊>Quaternary geochronology >Sediment accumulation rates in subarctic lakes: Insights into age-depth modeling from 22 dated lake records from the Northwest Territories, Canada
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Sediment accumulation rates in subarctic lakes: Insights into age-depth modeling from 22 dated lake records from the Northwest Territories, Canada

机译：北极圈内湖泊的沉积物沉积速率：加拿大西北地区22条有日期的湖泊记录对年龄深度建模的启示

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Age-depth modeling using Bayesian statistics requires well-informed prior information about the behavior of sediment accumulation. Here we present average sediment accumulation rates (represented as deposition times, DT, in yr/cm) for lakes in an Arctic setting, and we examine the variability across space (intra- and inter-lake) and time (late Holocene). The dataset includes over 100 radiocarbon dates, primarily on bulk sediment, from 22 sediment cores obtained from 18 lakes spanning the boreal to tundra ecotone gradients in subarctic Canada. There are four to twenty-five radiocarbon dates per core, depending on the length and character of the sediment records. Deposition times were calculated at 100-year intervals from age-depth models constructed using the 'classical' age-depth modeling software Clam. Lakes in boreal settings have the most rapid accumulation (mean DT 20 +/- 10 yr/cm), whereas lakes in tundra settings accumulate at moderate (mean DT 70 +/- 10 yr/cm) to very slow rates, (>100 yr/cm). Many of the age-depth models demonstrate fluctuations in accumulation that coincide with lake evolution and post-glacial climate change. Ten of our sediment cores yielded sediments as old as c. 9000 cal BP (BP = years before AD 1950). From between c. 9000 cal BP and c. 6000 cal BP, sediment accumulation was relatively rapid (DT of 20-60 yr/cm). Accumulation slowed between c. 5500 and c. 4000 cal BP as vegetation expanded northward in response to warming. A short period of rapid accumulation occurred near 1200 cal BP at three lakes. Our research will help inform priors in Bayesian age modeling. (C) 2015 Elsevier B.V. All rights reserved.
机译：使用贝叶斯统计数据进行年龄深度建模需要有关沉积物堆积行为的充分信息的先验信息。在这里，我们介绍了北极环境中湖泊的平均沉积物沉积速率（以沉积时间DT表示，以yr / cm为单位），并研究了整个空间（湖内和湖间）和时间（晚全新世）的变化性。该数据集包括100多个放射性碳数据，主要来自大量沉积物，这些碳沉积物来自于18个湖泊中的22个沉积物核心，横跨北亚北极的寒带至苔原过渡带。每个岩心有4至25个放射性碳数据，具体取决于沉积物记录的长度和特征。从使用“经典”年龄深度建模软件Clam构建的年龄深度模型以100年为间隔计算沉积时间。北方地区的湖泊积累最快（平均DT 20 +/- 10 yr / cm），而苔原地区的湖泊以中等速率（平均DT 70 +/- 10 yr / cm）积累到非常慢的速率（> 100 yr / cm）。许多年龄深度模型都显示出与湖泊演变和冰川后气候变化相吻合的蓄积波动。我们的十个沉积物核心产生的沉积物年龄与c一样长。 9000 cal BP（BP = AD 1950之前的年）。从之间c。 9000 cal BP和c。 6000 cal BP，沉积物积累相对较快（DT为20-60 yr / cm）。两次之间的积累减慢了。 5500和c。随着气候变暖，植被向北扩展，达到4000 cal BP。在三个湖泊的1200 cal BP附近发生了短暂的快速堆积。我们的研究将有助于为贝叶斯年龄建模提供先验信息。 （C）2015 Elsevier B.V.保留所有权利。

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