Melting at the base of the Greenland ice sheet explained by Iceland hotspot history
Melting at the base of the Greenland ice sheet explained by Iceland hotspot history
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DOI：
10.1038/ngeo2689
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发表时间：
2016-05
影响因子：
18.3
通讯作者：
I. Rogozhina;A. Petrunin;A. Vaughan;B. Steinberger;Jesse Johnson;M. Kaban;R. Calov;F. Rickers;Maik Thomas;I. Koulakov
中科院分区：
文献类型：
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作者：
I. Rogozhina;A. Petrunin;A. Vaughan;B. Steinberger;Jesse Johnson;M. Kaban;R. Calov;F. Rickers;Maik Thomas;I. Koulakov
穿透冰层的雷达和冰芯钻探显示，格陵兰中北部冰盖的大部分正在从下方融化。有人认为，基冰融化是由于异常高的地热通量，这也影响了格陵兰最长冰流的发展。在这里，我们估计了格陵兰冰盖下的地热通量，并在厚厚的冰盖下发现了1200公里长、400公里宽的地热异常。我们认为，这种异常现象解释了观测到的冰盖底部融化的现象，冰盖底部融化驱动了旺盛的冰下水文作用，并控制了神秘的格陵兰东北部750公里长冰流的源头位置。我们对独立的地震、重力和构造数据的综合分析表明，从西向东穿过格陵兰岛的地热异常是由大约8000万至3500万年前格陵兰越过冰岛地幔羽流形成的。我们的结论是，格陵兰中北部冰盖现今冰下水文和动力学特征的复杂性源于早于格陵兰冰川开始数千万年的构造事件。
Ice-penetrating radar,,and ice core drilling have shown that large parts of the north-central Greenland ice sheet are melting from below. It has been argued that basal ice melt is due to the anomalously high geothermal flux,that has also influenced the development of the longest ice stream in Greenland. Here we estimate the geothermal flux beneath the Greenland ice sheet and identify a 1,200-km-long and 400-km-wide geothermal anomaly beneath the thick ice cover. We suggest that this anomaly explains the observed melting of the ice sheet’s base, which drives the vigorous subglacial hydrology and controls the position of the head of the enigmatic 750-km-long northeastern Greenland ice stream. Our combined analysis of independent seismic, gravity and tectonic data,,,implies that the geothermal anomaly, which crosses Greenland from west to east, was formed by Greenland’s passage over the Iceland mantle plume between roughly 80 and 35 million years ago. We conclude that the complexity of the present-day subglacial hydrology and dynamic features of the north-central Greenland ice sheet originated in tectonic events that pre-date the onset of glaciation in Greenland by many tens of millions of years.