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Observed crustal uplift near the Southern Patagonian Icefield constrains improved viscoelastic Earth models
Author(s) -
Lange H.,
Casassa G.,
Ivins E. R.,
Schröder L.,
Fritsche M.,
Richter A.,
Groh A.,
Dietrich R.
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2013gl058419
Subject(s) - post glacial rebound , geology , ice field , lithosphere , geodetic datum , mantle (geology) , geodesy , viscoelasticity , climatology , glacial period , geophysics , seismology , geomorphology , glacier , tectonics , physics , thermodynamics
Thirty‒one GPS geodetic measurements of crustal uplift in southernmost South America determined extraordinarily high trend rates (> 35 mm/yr) in the north‒central part of the Southern Patagonian Icefield. These trends have a coherent pattern, motivating a refined viscoelastic glacial isostatic adjustment model to explain the observations. Two end‒member models provide good fits: both require a lithospheric thickness of 36.5 ± 5.3 km. However, one end‒member has a mantle viscosity near η =1.6 ×10 18 Pa s and an ice collapse rate from the Little Ice Age (LIA) maximum comparable to a lowest recent estimate of 1995–2012 ice loss at about −11 Gt/yr. In contrast, the other end‒member has much larger viscosity: η = 8.0 ×10 18 Pa s, half the post–LIA collapse rate, and a steadily rising loss rate in the twentieth century after AD 1943, reaching −25.9 Gt/yr during 1995–2012.