Upper mantle viscosity underneath northern Marguerite Bay, Antarctic Peninsula constrained by bedrock uplift and ice mass variability

We constrain viscoelastic Earth rheology and recent ice-mass change in the northern Marguerite Bay region of the Antarctic Peninsula. Global Positioning System (GPS) time series from Rothera and San Martin stations show bedrock uplift range of∼−0.81.8mm/year over 19992005 and 20162020 but ∼3.56.0mm/...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Samrat, NH, King, MA, Watson, C, Hay, A, Barletta, VR, Bordoni, A
Format: Article in Journal/Newspaper
Language:English
Published: Wiley-Blackwell Publishing, Inc. 2021
Subjects:
Earth Sciences
Geophysics
Geodesy
Antarctic
The Antarctic
Antarctic Peninsula
Marguerite
Rothera
Marguerite Bay
Antarc*
Online Access:https://doi.org/10.1029/2021GL097065
http://ecite.utas.edu.au/148439
Description
Summary:We constrain viscoelastic Earth rheology and recent ice-mass change in the northern Marguerite Bay region of the Antarctic Peninsula. Global Positioning System (GPS) time series from Rothera and San Martin stations show bedrock uplift range of∼−0.81.8mm/year over 19992005 and 20162020 but ∼3.56.0mm/year over ∼20052016. Digital elevation models reveal substantial surface lowering, but at a lower rate since ∼2009. Using these data, we show that an elastic-only model cannot explain the non-linear uplift of the GPS sites but that a layered viscoelastic model can. We show close agreement between GPS uplift changes and viscoelastic models with effective elastic lithosphere thickness and upper-mantle viscosity ∼1095km and ∼0.1−910 18 Pa s, respectively. Our viscosity estimate is consistent with a north-south gradient in viscosity suggested by previous studies focused on specific regions within the Antarctic Peninsula and adds further evidence of the low viscosity upper mantle in the northern Antarctic Peninsula.

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