Observed rapid bedrock uplift in Amundsen Sea Embayment promotes ice-sheet stability

Barletta, V; Bevis, Michael; Smith, B. E.; Wilson, T. J.; Brown, Abel; Bordoni, Andrea; Willis, M. J.; Khan, Shfaqat Abbas; Rovira‐Navarro, Marc; Dalziel, Ian W. D.; Smalley, Robert; Kendrick, Eric; Konfal, S. A.; Caccamise, Dana J.; Aster, R. C.; Nyblade, A. A.; Wiens, Douglas A.

doi:10.1126/science.aao1447

Cited by 176 publications

(332 citation statements)

References 76 publications

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“…Considering that this area holds ~25% of the WAIS within its drainage basins (Larter et al, ), the slow Vs, together with the thin crust and lithosphere, have a particular importance for the possible linkage between future Antarctic ice sheet collapse rate and mantle viscosity‐mediated GIA (Gomez et al, ). Recent observations of extremely rapid uplift caused by GIA can only be modeled with very thin lithosphere and low‐viscosity upper mantle (Barletta et al, ), consistent with the findings presented here.…”

Section: Discussionsupporting

confidence: 92%

The Crust and Upper Mantle Structure of Central and West Antarctica From Bayesian Inversion of Rayleigh Wave and Receiver Functions

Wiens²,

et al. 2018

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We construct a new seismic model for central and West Antarctica by jointly inverting Rayleigh wave phase and group velocities along with P wave receiver functions. Ambient noise tomography exploiting data from more than 200 seismic stations deployed over the past 18 years is used to construct Rayleigh wave phase and group velocity dispersion maps. Comparison between the ambient noise phase velocity maps with those constructed using teleseismic earthquakes confirms the accuracy of both results. These maps, together with P receiver function waveforms, are used to construct a new 3‐D shear velocity (Vs) model for the crust and uppermost mantle using a Bayesian Monte Carlo algorithm. The new 3‐D seismic model shows the dichotomy of the tectonically active West Antarctica (WANT) and the stable and ancient East Antarctica (EANT). In WANT, the model exhibits a slow uppermost mantle along the Transantarctic Mountains (TAMs) front, interpreted as the thermal effect from Cenozoic rifting. Beneath the southern TAMs, the slow uppermost mantle extends horizontally beneath the traditionally recognized EANT, hypothesized to be associated with lithospheric delamination. Thin crust and lithosphere observed along the Amundsen Sea coast and extending into the interior suggest involvement of these areas in Cenozoic rifting. EANT, with its relatively thick and cold crust and lithosphere marked by high Vs, displays a slower Vs anomaly beneath the Gamburtsev Subglacial Mountains in the uppermost mantle, which we hypothesize may be the signature of a compositionally anomalous body, perhaps remnant from a continental collision.

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Section: Discussionsupporting

confidence: 92%

The Crust and Upper Mantle Structure of Central and West Antarctica From Bayesian Inversion of Rayleigh Wave and Receiver Functions

Wiens²,

et al. 2018

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“…This provides a mechanism for the readvance invoked by Bradley et al (). These processes may be particularly important for the WAIS, where mantle viscosity is relatively low and GIA can respond on relatively short time and length scales (Barletta et al, ; Gomez et al, ).…”

Section: Discussionmentioning

confidence: 99%

Holocene Formation of Henry Ice Rise, West Antarctica, Inferred From Ice‐Penetrating Radar

Wearing

Kingslake

2019

JGR Earth Surface

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Ice rises are regions of grounded ice embedded within floating ice shelves. The deformation of ice past them increases the back stress generated by the ice shelf, slowing the flow of the ice sheet. We present ground‐based ice‐penetrating radar data from Henry Ice Rise in the Ronne Ice Shelf, West Antarctica, that indicates regrounding during the Holocene. Relic crevasses and melt synclines are observed upstream of the present‐day grounding line. We conclude that these features formed during a previous flow configuration, from which the grounding line has since advanced to its current position. In agreement with previous work, our observations can be explained if initial grounding of the ice shelf occurred on a bathymetric high, forming an ice rumple that migrated upstream and temporarily ungrounded over the topographic high. The grounding line then advanced, preserving relic basal crevasses in the newly grounded ice. Using a simple ice‐flow model, we simulate the burial of these crevasses. While accounting for uncertainty in accumulation, firn density, radar‐derived depth, ice‐thickening history, initial crevasse height, and glacial isostatic adjustment, we estimate a burial time of 6 ± 2 kyr before present for the oldest relic crevasses, indicating that the ice rise formed at approximately this time. This potentially increased the buttressing generated by the Ronne Ice Shelf, causing thickening and advance of the ice sheet. By dating the formation and providing details of ice‐rise formation, these new results can provide useful constraints on both large‐scale ice‐sheet models and models of ice‐rumple and ice‐rise formation.

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“…The genuineness of a GIA uplift in ASE was then confirmed by once they constrained spatial wavelength of GIA using forward models. The pronounced GIA-induced uplift is supported by recent GIA models that consider late Holocene IMC which seem to dominate present-day GIA rates in regions that have a thinner lithosphere and a lower mantle viscosity (Barletta et al, 2018;Gomez et al, 2018). The pronounced GIA-induced uplift is supported by recent GIA models that consider late Holocene IMC which seem to dominate present-day GIA rates in regions that have a thinner lithosphere and a lower mantle viscosity (Barletta et al, 2018;Gomez et al, 2018).…”

Section: Discussionmentioning

confidence: 62%

“…Sasgen et al (2017), identical to Martín-Español, Zammit-Mangion, et al (2016, derived strong GIA signal in ASE by combining complementary geodetic observations when considering the weak Earth structure in the determination of the viscoelastic response functions they utilized. According to Barletta et al (2018), the forward-modeled GIA correction over the Antarctic basins 21 and 22 (Zwally et al, 2012) for the GRACE-derived mass loss is between 13.5 and 19.4 Gt/year. According to Barletta et al (2018), the forward-modeled GIA correction over the Antarctic basins 21 and 22 (Zwally et al, 2012) for the GRACE-derived mass loss is between 13.5 and 19.4 Gt/year.…”

Section: Discussionmentioning

confidence: 99%

“…The latter is particularly important when combining data from GRACE with data from other observational techniques. Note that the methodology developed in this study is applicable to other temporal resolutions as long as auxiliary data are available, particularly when the assumption regarding the linearity of the GIA signal might not be valid (Barletta et al, 2018). The ICESat mission period restricts the time span under investigation, from February 2003 to October 2009.…”

Section: Data Setsmentioning

confidence: 99%

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Separating Geophysical Signals Using GRACE and High‐Resolution Data: A Case Study in Antarctica

Engels

Gunter

Riva

et al. 2018

Geophysical Research Letters

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To fully exploit data from the Gravity Recovery and Climate Experiment (GRACE), we separate geophysical signals observed by GRACE in Antarctica by deriving high‐spatial resolution maps for present‐day glacial isostatic adjustment (GIA) and ice‐mass changes with the least possible noise level. For this, we simultaneously (i) improve the postprocessing of gravity data and (ii) consistently combine them with high‐resolution data from Ice Cloud and land Elevation Satellite altimeter (ICESat) and Regional Atmospheric Climate Model 2.3 (RACMO). We use GPS observations to discriminate between various candidate spatial patterns of vertical motions caused by GIA. The ICESat‐RACMO combination determines the spatial resolution of estimated ice‐mass changes. The results suggest the capability of the developed approach to retrieve the complex spatial pattern of present‐day GIA, such as a pronounced subsidence in the proximity of the Kamb Ice Stream and pronounced uplift in the Amundsen Sea Sector.

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Observed rapid bedrock uplift in Amundsen Sea Embayment promotes ice-sheet stability

Cited by 176 publications

References 76 publications

The Crust and Upper Mantle Structure of Central and West Antarctica From Bayesian Inversion of Rayleigh Wave and Receiver Functions

The Crust and Upper Mantle Structure of Central and West Antarctica From Bayesian Inversion of Rayleigh Wave and Receiver Functions

Holocene Formation of Henry Ice Rise, West Antarctica, Inferred From Ice‐Penetrating Radar

Separating Geophysical Signals Using GRACE and High‐Resolution Data: A Case Study in Antarctica

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