Rapid bedrock uplift in the Antarctic Peninsula explained by viscoelastic response to recent ice unloading
Rapid bedrock uplift in the Antarctic Peninsula explained by viscoelastic response to recent ice unloading
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DOI：
10.1016/j.epsl.2014.04.019
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发表时间：
2014-07-01
影响因子：
5.3
通讯作者：
Berthier, Etienne
中科院分区：
文献类型：
--
作者：
Nield, Grace A.;Barletta, Valentina R.;Berthier, Etienne
自1995年以来，南极半岛北方的几个冰架已经倒塌，并引发了冰块卸载，引发了连续GPS（cGPS）站记录的固体地球响应。先前试图模拟2002年拉森B冰架破裂后的快速隆升观测结果，但由于对冰卸载模式的了解不完整，可能还假设只有弹性机制，因此受到限制。我们利用一个新的高分辨率数据集的冰海拔变化，捕捉冰质量损失以北的66 S，首先表明，自2002年以来的帕尔默cGPS站的非线性隆起不能单独用弹性变形来解释。我们应用线性麦克斯韦流变学的粘弹性模型来预测自1995年以来的隆升，并测试适合帕尔默cGPS时间序列，发现一个很好的约束上地幔粘度，但对岩石圈厚度的敏感性较低。我们进一步限制最佳拟合地球模型，包括2009年后部署的6个cGPS站（LARISSA网络），垂直速度范围为1.7至14.9毫米/年。这导致了一个最适合的地球模型，岩石圈厚度为100-140 km，上地幔粘度为6 x 10（17）-2 x 10（18）Pas -比以前建议的该地区低得多。结合LARISSA时间序列与帕尔默cGPS时间序列提供了一个难得的机会来研究的时间演化的低粘度固体地球响应一个良好的捕获冰卸载事件。(C)2014作者由爱思唯尔公司出版
Since 1995 several ice shelves in the Northern Antarctic Peninsula have collapsed and triggered ice-mass unloading, invoicing a solid Earth response that has been recorded at continuous GPS (cGPS) stations. A previous attempt to model the observation of rapid uplift following the 2002 breakup of Larsen B Ice Shelf was limited by incomplete knowledge of the pattern of ice unloading and possibly the assumption of an elastic-only mechanism. We make use of a new high resolution dataset of ice elevation change that captures ice-mass loss north of 66 S to first show that non-linear uplift of the Palmer cGPS station since 2002 cannot be explained by elastic deformation alone. We apply a viscoelastic model with linear Maxwell rheology to predict uplift since 1995 and test the fit to the Palmer cGPS time series, finding a well constrained upper mantle viscosity but less sensitivity to lithospheric thickness. We further constrain the best fitting Earth model by including six cGPS stations deployed after 2009 (the LARISSA network), with vertical velocities in the range 1.7 to 14.9 mm/yr. This results in a best fitting Earth model with lithospheric thickness of 100-140 km and upper mantle viscosity of 6 x 10(17)-2 x 10(18) Pas - much lower than previously suggested for this region. Combining the LARISSA time series with the Palmer cGPS time series offers a rare opportunity to study the time-evolution of the low-viscosity solid Earth response to a well-captured ice unloading event. (C) 2014 The Authors. Published by Elsevier B.V.