Upper mantle structure of central and West Antarctica from array analysis of Rayleigh wave phase velocities

David S. Heeszel, Douglas A. Wiens, Sridhar Anandakrishnan, Richard C. Aster, Ian W.D. Dalziel, Audrey D. Huerta, Andrew Arnold Nyblade, Terry J. Wilson, J. Paul Winberry

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The seismic velocity structure of Antarctica is important, both as a constraint on the tectonic history of the continent and for understanding solid Earth interactions with the ice sheet. We use Rayleigh wave array analysis methods applied to teleseismic data from recent temporary broadband seismograph deployments to image the upper mantle structure of central and West Antarctica. Phase velocity maps are determined using a two-plane wave tomography method and are inverted for shear velocity using a Monte Carlo approach to estimate three-dimensional velocity structure. Results illuminate the structural dichotomy between the East Antarctic Craton and West Antarctica, with West Antarctica showing thinner crust and slower upper mantle velocity. West Antarctica is characterized by a 70-100 km thick lithosphere, underlain by a low-velocity zone to depths of at least 200 km. The slowest anomalies are beneath Ross Island and the Marie Byrd Land dome and are interpreted as upper mantle thermal anomalies possibly due to mantle plumes. The central Transantarctic Mountains are marked by an uppermost mantle slow-velocity anomaly, suggesting that the topography is thermally supported. The presence of thin, higher-velocity lithosphere to depths of about 70 km beneath the West Antarctic Rift System limits estimates of the regionally averaged heat flow to less than 90 mW/m2. The Ellsworth-Whitmore block is underlain by mantle with velocities that are intermediate between those of the West Antarctic Rift System and the East Antarctic Craton. We interpret this province as Precambrian continental lithosphere that has been altered by Phanerozoic tectonic and magmatic activity.

Original languageEnglish (US)
Pages (from-to)1758-1775
Number of pages18
JournalJournal of Geophysical Research: Solid Earth
Volume121
Issue number3
DOIs
StatePublished - Mar 1 2016

Fingerprint

Rayleigh waves
mantle structure
Phase velocity
phase velocity
Rayleigh wave
Antarctic regions
wave velocity
upper mantle
Earth mantle
lithosphere
velocity structure
craton
cratons
anomalies
mantle
Tectonics
anomaly
solid Earth
tectonics
low velocity zone

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Heeszel, David S. ; Wiens, Douglas A. ; Anandakrishnan, Sridhar ; Aster, Richard C. ; Dalziel, Ian W.D. ; Huerta, Audrey D. ; Nyblade, Andrew Arnold ; Wilson, Terry J. ; Winberry, J. Paul. / Upper mantle structure of central and West Antarctica from array analysis of Rayleigh wave phase velocities. In: Journal of Geophysical Research: Solid Earth. 2016 ; Vol. 121, No. 3. pp. 1758-1775.
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Upper mantle structure of central and West Antarctica from array analysis of Rayleigh wave phase velocities. / Heeszel, David S.; Wiens, Douglas A.; Anandakrishnan, Sridhar; Aster, Richard C.; Dalziel, Ian W.D.; Huerta, Audrey D.; Nyblade, Andrew Arnold; Wilson, Terry J.; Winberry, J. Paul.

In: Journal of Geophysical Research: Solid Earth, Vol. 121, No. 3, 01.03.2016, p. 1758-1775.

Research output: Contribution to journalArticle

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AU - Heeszel, David S.

AU - Wiens, Douglas A.

AU - Anandakrishnan, Sridhar

AU - Aster, Richard C.

AU - Dalziel, Ian W.D.

AU - Huerta, Audrey D.

AU - Nyblade, Andrew Arnold

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AU - Winberry, J. Paul

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N2 - The seismic velocity structure of Antarctica is important, both as a constraint on the tectonic history of the continent and for understanding solid Earth interactions with the ice sheet. We use Rayleigh wave array analysis methods applied to teleseismic data from recent temporary broadband seismograph deployments to image the upper mantle structure of central and West Antarctica. Phase velocity maps are determined using a two-plane wave tomography method and are inverted for shear velocity using a Monte Carlo approach to estimate three-dimensional velocity structure. Results illuminate the structural dichotomy between the East Antarctic Craton and West Antarctica, with West Antarctica showing thinner crust and slower upper mantle velocity. West Antarctica is characterized by a 70-100 km thick lithosphere, underlain by a low-velocity zone to depths of at least 200 km. The slowest anomalies are beneath Ross Island and the Marie Byrd Land dome and are interpreted as upper mantle thermal anomalies possibly due to mantle plumes. The central Transantarctic Mountains are marked by an uppermost mantle slow-velocity anomaly, suggesting that the topography is thermally supported. The presence of thin, higher-velocity lithosphere to depths of about 70 km beneath the West Antarctic Rift System limits estimates of the regionally averaged heat flow to less than 90 mW/m2. The Ellsworth-Whitmore block is underlain by mantle with velocities that are intermediate between those of the West Antarctic Rift System and the East Antarctic Craton. We interpret this province as Precambrian continental lithosphere that has been altered by Phanerozoic tectonic and magmatic activity.

AB - The seismic velocity structure of Antarctica is important, both as a constraint on the tectonic history of the continent and for understanding solid Earth interactions with the ice sheet. We use Rayleigh wave array analysis methods applied to teleseismic data from recent temporary broadband seismograph deployments to image the upper mantle structure of central and West Antarctica. Phase velocity maps are determined using a two-plane wave tomography method and are inverted for shear velocity using a Monte Carlo approach to estimate three-dimensional velocity structure. Results illuminate the structural dichotomy between the East Antarctic Craton and West Antarctica, with West Antarctica showing thinner crust and slower upper mantle velocity. West Antarctica is characterized by a 70-100 km thick lithosphere, underlain by a low-velocity zone to depths of at least 200 km. The slowest anomalies are beneath Ross Island and the Marie Byrd Land dome and are interpreted as upper mantle thermal anomalies possibly due to mantle plumes. The central Transantarctic Mountains are marked by an uppermost mantle slow-velocity anomaly, suggesting that the topography is thermally supported. The presence of thin, higher-velocity lithosphere to depths of about 70 km beneath the West Antarctic Rift System limits estimates of the regionally averaged heat flow to less than 90 mW/m2. The Ellsworth-Whitmore block is underlain by mantle with velocities that are intermediate between those of the West Antarctic Rift System and the East Antarctic Craton. We interpret this province as Precambrian continental lithosphere that has been altered by Phanerozoic tectonic and magmatic activity.

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