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Rapid bedrock uplift in the Antarctic Peninsula explained by viscoelastic response to recent ice unloading

Lookup NU author(s): Grace Nield, Professor Matt King, Professor Peter Clarke

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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Abstract

Since 1995 several ice shelves in the Northern Antarctic Peninsula have collapsed and triggered ice-mass unloading, invoking 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 View the MathML source6×1017–2×1018 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.


Publication metadata

Author(s): Nield GA, Barletta VR, Bordoni A, King MA, Whitehouse PL, Clarke PJ, Domack E, Scambos TA, Berthier E

Publication type: Article

Publication status: Published

Journal: Earth and Planetary Science Letters

Year: 2014

Volume: 397

Pages: 32-41

Print publication date: 01/07/2014

Online publication date: 05/05/2014

Acceptance date: 09/04/2014

Date deposited: 22/07/2014

ISSN (print): 0012-821X

ISSN (electronic): 1385-013X

Publisher: Elsevier BV

URL: http://dx.doi.org/10.1016/j.epsl.2014.04.019

DOI: 10.1016/j.epsl.2014.04.019


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