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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 ∼−0.8–1.8 mm/year over 1999–2005 and 2016–2020 but ∼3.5–6.0 mm/year over ∼2005–2016. 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 ∼10–95 km and ∼0.1−9 × 1018 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.
Funding
Australian Research Council
History
Publication title
Geophysical Research LettersVolume
48Issue
24Article number
e2021GL097065Number
e2021GL097065ISSN
1944-8007Department/School
School of Geography, Planning and Spatial SciencesPublisher
Wiley-Blackwell Publishing, Inc.Place of publication
United StatesRights statement
© 2021. American Geophysical Union. All Rights Reserved.Repository Status
- Restricted