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

journal contribution
posted on 21.06.2022, 02:03 authored by Nahidul Samrat, Matt A King, Christopher Watson, Andrea Hay, Valentina R Barletta, Andrea Bordoni
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.

History

Volume

48

Issue

24

Start Page

1

End Page

9

Number of Pages

9

eISSN

1944-8007

ISSN

0094-8276

Publisher

American Geophysical Union

Language

en

Peer Reviewed

Yes

Open Access

No

Acceptance Date

17/11/2021

External Author Affiliations

University of Tasmania; Technical University of Denmar

Era Eligible

Yes

Journal

Geophysical Research Letters