Rapid early Holocene ice retreat in West Greenland
Rapid early Holocene ice retreat in West Greenland
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西格陵兰岛全新世早期冰层快速退缩
DOI：
10.1016/j.quascirev.2013.05.027
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发表时间：
2014
影响因子：
4
通讯作者：
H. Linge
中科院分区：
文献类型：
--
作者：
N. K. Larsen;S. Funder;K. Kjær;K. Kjeldsen;M. Knudsen;H. Linge
格陵兰冰盖可能消亡及其对全球海平面的影响是对社会最严重的气候威胁之一。为了提高我们对冰缘未来行为的了解，我们使用 47 个宇宙成因 10Be 暴露年龄、26 个光刺激发光年龄以及 15 个新的和 28 个先前发布的放射性碳年龄，研究了冰盖对格陵兰岛西部全新世早期变暖的响应。成对的基岩和巨石年龄表明，在末次盛冰期 (LGM) 期间，整个区域都被暖基冰覆盖，尽管冰川侵蚀不足以完全去除含有 10Be 的上层岩石表面，这些岩石表面是从之前暴露在海拔 800 米以上的基岩样本中继承下来的。我们对 10Be 和 14C 年龄的汇编表明，冰盖从外海岸退缩到了现在的冰缘。 11.4 和 10.4 口径。 Godthåbsfjord 系统的 ka BP 以及 Buksefjord 的 10.7 ± 0.6 和 10.1 ± 0.4 ka 之间，而 Sermilik 的海岸在 10.7 ± 0.6 和 10.1 ± 0.4 ka 之间变得无冰。 10.5 卡路里 ka BP。我们发现，深戈特霍布斯峡湾系统和布克峡湾-塞尔米利克地区之间的退缩率没有显着变化，该地区只有少数狭窄而浅的峡湾。然而，冰消作用开始了c。 700-900年前的Godthåbsfjord系统表明，深峡湾可能通过动态冰损失引发了陆基冰川消融，导致全新世早期冰整体快速退缩，并导致西格陵兰冰盖下降。这些结果表明，即使冰川消融的发生受到地形控制，快速冰退缩也不限于深峡湾系统，而是可能独立于地形环境而发生。
The possible demise of the Greenland ice sheet and its effect on global sea level rank among the most serious climate threats to society. To improve our knowledge about the future behaviour of the ice margin, we studied the ice sheet's response to early Holocene warming in West Greenland using 47 cosmogenic10Be exposure ages, 26 optically-stimulated luminescence ages as well as 15 new and 28 previously published radiocarbon ages. Paired bedrock and boulder ages show that the entire area was covered by warm-based ice during the Last Glacial Maximum (LGM), although glacial erosion was insufficient to completely remove the upper rock surface containing10Be inherited from a previous period of exposure in bedrock samples above an elevation of 800 m. Our compilation of10Be and14C ages demonstrates that the ice sheet retreated from the outer-coast to the present ice margin between c. 11.4 and 10.4 cal. ka BP in the Godthåbsfjord system and between 10.7 ± 0.6 and 10.1 ± 0.4 ka ago in Buksefjord, whereas the coast at Sermilik became ice free at c. 10.5 cal. ka BP. We find no significant changes in the retreat rates between the deep Godthåbsfjord system and the Buksefjord-Sermilik region, which is characterized by only a few narrow and shallow fjords. However, deglaciation was initiated c. 700–900 years earlier in the Godthåbsfjord system indicating that the deep fjords probably triggered land-based deglaciation by dynamic ice loss leading to an overall rapid early Holocene ice retreat and drawdown of the ice sheet in West Greenland. These results demonstrate that even if there was a topographic control on the onset of deglaciation, fast ice retreat is not restricted to deep fjord systems but may occur independently of the topographic setting.