Restricted impact of Holocene climate variations on the southern Greenland Ice Sheet
Restricted impact of Holocene climate variations on the southern Greenland Ice Sheet
复制标题
DOI：
10.1016/j.quascirev.2011.07.022
复制
发表时间：
2011-10
影响因子：
4
通讯作者：
N. K. Larsen;K. Kjær;J. Olsen;S. Funder;K. Kjeldsen;N. Nørgaard‐Pedersen
中科院分区：
文献类型：
--
作者：
N. K. Larsen;K. Kjær;J. Olsen;S. Funder;K. Kjeldsen;N. Nørgaard‐Pedersen
我们使用格陵兰南部的一个冰边缘“阈值湖”Lower Nordbosø记录了格陵兰南部冰盖（sGIS）接近现在的时期，以碎屑沉积物床为代表，而gyttja沉积反映了冰川低于阈值的时期，没有冰川融水输入。结果表明，沉积作用开始于约10.6 cal ka BP，此时冰缘已经过消冰期达到现在的程度。在此之后，冰缘一直保持在接近现在的范围，直到c. 6.9 cal ka BP，冰缘退缩到阈值后，在c. 3.0 ~ 2.8 cal ka BP和c. 0.5 cal ka BP直到现在首次出现明显的冰川信号。下Nordbosø的碎屑输入与Narsaq Sound的IRD事件之间总体上具有良好的相关性，表明它们代表了sGIS的一般冰川接近信号。我们的数据表明，与以前的重建相比，sGIS对全新世气候变化的表现不那么强烈。在格陵兰岛南部山区，冰盖仅在c. 6.9 ~ 3.0 cal ka BP和c. 2.8 ~ 0.5 cal ka BP退缩到现在的冰范围之后，而在c. 9 ka至小冰期，更敏感的低洼卡西缪特裂片则落后于现在的边缘。因此，格陵兰岛南部的冰缘行为不仅受气候变化的支配，而且受当地地形环境的强烈影响。
We use an ice marginal "threshold lake", Lower Nordbosø, in southern Greenland to record episodes when the southern Greenland Ice Sheet (sGIS) was close to the present extent, represented by beds of clastic sediments whereas gyttja-deposition reflects periods when the glacier was behind the threshold, and no glacial meltwater input. The results show that the sedimentation was initiated at c. 10.6 cal ka BP when the ice margin had reached the present extent following the deglaciation. After this the ice margin remained close to the present extent until c. 6.9 cal ka BP when it retreated behind the threshold and first reappeared with a clear glacial signal at c. 3.0–2.8 cal. ka BP and from c. 0.5 cal ka BP until the present. An overall good correlation between clastic input into Lower Nordbosø and IRD events from Narsaq Sound suggests that they represent a general glacial proximity signal of the sGIS. Our data demonstrates that the sGIS behaved less vigorously to Holocene climate changes compared to previous reconstructions. The ice sheet only retreated behind the present ice extent from c. 6.9 to 3.0 cal ka BP and c. 2.8 to 0.5 cal ka BP in the mountainous southern Greenland, whereas the more sensitive low-lying Qassimiut lobe was behind its present margin from c. 9 ka until the Little Ice Age. Accordingly, the ice marginal behavior in southern Greenland is not only governed by climate changes but also strongly influenced by the local topographic setting.