East Antarctic rifting triggers uplift of the Gamburtsev Mountains
East Antarctic rifting triggers uplift of the Gamburtsev Mountains
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DOI：
10.1038/nature10566
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发表时间：
2011-11-17
期刊：
影响因子：
64.8
通讯作者：
Damaske, Detlef
中科院分区：
文献类型：
--
作者：
Ferraccioli, Fausto;Finn, Carol A.;Damaske, Detlef
甘布尔采夫冰下山脉是地球上最不为人所知的构造特征，因为它们完全隐藏在东南极冰盖之下。它们的高海拔和年轻的阿尔卑斯山地形，加上它们在东南极克拉通的位置，创造了一个自1958年发现以来一直困扰研究人员的悖论。甘布尔采夫山脉（2）的阿尔卑斯山地形得以保存，可能反映了冰盖下极低的长期侵蚀率（3），但山脉的起源仍然存在问题。在这里，我们提出了第一个全面的地壳结构和隆升机制的Gamburtsev，来自雷达，重力和磁力数据。地球物理数据确定了在东南极洲Gamburtsev山脉周围有一个2,500公里长的裂谷系统，山脉下面有一个厚厚的地壳根。我们认为，根形成于南极洲东部内部的元古宙组装（可能约1 Gyr前），像在一些古老的造山带中一样被保存下来（5，6），并在更晚的二叠纪（约2.5亿年前）和白垩纪（约1亿年前）裂谷作用中恢复活力。与东非（7）非常相似，东南极洲的内部是受裂谷过程影响的前寒武纪省份的马赛克。我们的模型表明，裂谷侧翼隆起，根浮力和均衡响应河流和冰川侵蚀的组合解释了高海拔和救济的甘布尔采夫。Gamburtsev的演化表明，裂谷和保存的造山根可以产生广泛的地区，在大陆内部的高地形，而不显着修改下面的前寒武纪岩石圈。
The Gamburtsev Subglacial Mountains are the least understood tectonic feature on Earth, because they are completely hidden beneath the East Antarctic Ice Sheet. Their high elevation and youthful Alpine topography, combined with their location on the East Antarctic craton, creates a paradox that has puzzled researchers since the mountains were discovered in 1958(1). The preservation of Alpine topography in the Gamburtsevs(2) may reflect extremely low long-term erosion rates beneath the ice sheet(3), but the mountains' origin remains problematic. Here we present the first comprehensive view of the crustal architecture and uplift mechanisms for the Gamburtsevs, derived from radar, gravity and magnetic data. The geophysical data define a 2,500-km-long rift system in East Antarctica surrounding the Gamburtsevs, and a thick crustal root(4) beneath the range. We propose that the root formed during the Proterozoic assembly of interior East Antarctica (possibly about 1 Gyr ago), was preserved as in some old orogens(5,6) and was rejuvenated during much later Permian (roughly 250 Myr ago) and Cretaceous (roughly 100 Myr ago) rifting. Much like East Africa(7), the interior of East Antarctica is a mosaic of Precambrian provinces affected by rifting processes. Our models show that the combination of rift-flank uplift, root buoyancy and the isostatic response to fluvial and glacial erosion explains the high elevation and relief of the Gamburtsevs. The evolution of the Gamburtsevs demonstrates that rifting and preserved orogenic roots can produce broad regions of high topography in continental interiors without significantly modifying the underlying Precambrian lithosphere.