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Multi-phased deglaciation of south and southeast Greenland controlled by climate and topographic setting
Quaternary Science Reviews ( IF 4 ) Pub Date : 2020-08-01 , DOI: 10.1016/j.quascirev.2020.106454
Laura B. Levy , Nicolaj K. Larsen , Mads F. Knudsen , David L. Egholm , Anders A. Bjørk , Kristian K. Kjeldsen , Meredith A. Kelly , Jennifer A. Howley , Jesper Olsen , Dmitry Tikhomirov , Susan R.H. Zimmerman , Kurt H. Kjær

Abstract To put recent Greenland Ice Sheet (GrIS) ice loss into a longer-term context, we must understand its behavior during late-glacial and Early Holocene warming. Previous results seem to suggest that there is a large contrast in the timing of deglaciation between South and Southeast Greenland. However, because of lack of available data, in particular in Southeast Greenland, it is difficult to assess how the ice sheet responded to major late-glacial and Early Holocene climate changes. In this study, we use 41 new 10Be ages to constrain the deglaciation chronology in 12 new locations from the coast to the present ice margin in South and Southeast Greenland. We find that South Greenland (south of 61.5°N) deglaciated between ∼14.8 and 11.9 ka, whereas Southeast Greenland (61.5°N to 68.2°N) deglaciated between ∼11.4 and 11.3 ka. The deglaciation of the coastal, low-intermediate topography in South Greenland coincides with increased air surface temperatures during the Bolling-Allerod with fjords continuing to deglaciate into the Early Holocene. In contrast, the ice sheet persisted at the coast until the late-glacial and Early Holocene in Southeast Greenland, likely because of increased precipitation in the high alpine topography and fjord geometry and bathymetry (e.g. width of fjords and presence of sills). This multi-phased deglaciation demonstrates a contrasting response of the southern GrIS to changes in climate and variations in topographic setting, and that the spatial deglaciation of the GrIS was complex and likely did not respond to a single external climate forcing.

中文翻译:

受气候和地形环境控制的格陵兰南部和东南部多期冰川消退

摘要 为了将最近的格陵兰冰盖 (GrIS) 冰损失置于更长期的背景下,我们必须了解其在晚冰期和早全新世变暖期间的行为。先前的结果似乎表明格陵兰南部和东南部之间冰川消退的时间存在很大差异。然而,由于缺乏可用数据,特别是在格陵兰东南部,很难评估冰盖如何对主要的晚冰期和早全新世气候变化做出反应。在这项研究中,我们使用 41 个新的 10Be 年龄来限制从海岸到格陵兰南部和东南部目前冰缘的 12 个新地点的冰消年代学。我们发现南格陵兰岛(61.5°N 以南)在 14.8 到 11.9 ka 之间消融,而格陵兰东南部(61.5°N 到 68.2°N)在 11.4 和 11.3 ka 之间消融。格陵兰南部沿海中低地形的冰川消融与 Bolling-Allerod 期间空气表面温度升高相吻合,峡湾继续消融进入全新世早期。相比之下,冰盖在格陵兰东南部的晚冰期和全新世早期一直存在于海岸,这可能是因为高山地形和峡湾几何形状和水深测量(例如峡湾的宽度和门槛的存在)中降水增加。这种多阶段冰消作用表明南 GrIS 对气候变化和地形环境变化的不同响应,并且 GrIS 的空间冰消作用很复杂,可能对单一的外部气候强迫没有响应。格陵兰南部的中低地形恰逢 Bolling-Allerod 期间空气表面温度升高,峡湾继续冰川消融进入全新世早期。相比之下,冰盖在格陵兰东南部的晚冰期和全新世早期一直存在于海岸,这可能是因为高山地形和峡湾几何形状和水深测量(例如峡湾的宽度和门槛的存在)中降水增加。这种多阶段冰消作用表明南 GrIS 对气候变化和地形环境变化的不同响应,并且 GrIS 的空间冰消作用很复杂,可能对单一的外部气候强迫没有响应。格陵兰南部的中低地形恰逢 Bolling-Allerod 期间空气表面温度升高,峡湾继续冰川消融进入全新世早期。相比之下,冰盖在格陵兰东南部的晚冰期和全新世早期一直存在于海岸,这可能是因为高山地形和峡湾几何形状和水深测量(例如峡湾的宽度和基石的存在)的降水增加。这种多阶段冰消作用表明南 GrIS 对气候变化和地形环境变化的不同响应,并且 GrIS 的空间冰消作用很复杂,可能对单一的外部气候强迫没有响应。冰盖一直存在于海岸,直到格陵兰东南部的晚冰期和早全新世,这可能是因为高山地形和峡湾几何形状和水深测量(例如峡湾的宽度和门槛的存在)的降水增加。这种多阶段冰消作用表明南 GrIS 对气候变化和地形环境变化的不同响应,并且 GrIS 的空间冰消作用很复杂,可能对单一的外部气候强迫没有响应。冰盖一直存在于海岸,直到格陵兰东南部的晚冰期和早全新世,这可能是因为高山地形和峡湾几何形状和水深测量(例如峡湾的宽度和门槛的存在)的降水增加。这种多阶段冰消作用表明南 GrIS 对气候变化和地形环境变化的不同响应,并且 GrIS 的空间冰消作用很复杂,可能对单一的外部气候强迫没有响应。
更新日期:2020-08-01
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