Evolution of Neogene volcanism and stress patterns in the glaciated West Antarctic Rift, Marie Byrd Land, Antarctica

Paulsen, Timothy; Wilson, T. J.

doi:10.1144/0016-76492009-044

Cited by 18 publications

(14 citation statements)

References 89 publications

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“…In turn, this suggests that some long‐term changes in ice‐sheet size and behavior result from interactions with the lithosphere and thus that the climatic history of ice‐age cycling has been affecting geologic processes [ Clark and Pollard , ; Huybers and Langmuir , ; Crowley et al ., ; Sternai et al ., ]. In addition, we suggest that these processes are not limited to Greenland but could be as important, or more important, in West Antarctica and perhaps elsewhere [ Llubes et al ., ; Huybers and Langmuir , ; Paulsen and Wilson , ; Schroeder et al ., ].…”

Section: Discussionmentioning

confidence: 99%

Enhancement of volcanism and geothermal heat flux by ice‐age cycling: A stress modeling study of Greenland

2016

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Ice‐age cycling of the Greenland ice sheet likely contributed to locally elevated subglacial geothermal heat fluxes (GHFs), based on recent thermal modeling. Borehole and geophysical data indicate higher GHF in some areas than suggested by current knowledge of underlying geology, particularly at the head of the Northeast Greenland Ice Stream. Changes in lithospheric loading during ice‐sheet growth and decay cycles produce large and geologically rapid changes in the effective stress state beneath and near the ice sheet. Oscillations in melt fraction from cyclic loading through multiple ice‐age cycles will enhance upward magma migration through the nonlinear increase of melt migration velocity with melt fraction. We simulate periodic ice‐sheet loading scenarios along an east‐west transect across central Greenland on an Elastic Lithosphere, Relaxed Asthenosphere Earth model. Under likely parameter ranges, deviatoric stresses in the elastic lithosphere across widespread regions are sufficiently high to meaningfully enhance dike emplacement and also allow vug‐wave propagation in some scenarios. Stress patterns migrate laterally in response to ice‐sheet dynamics, favoring multistage magma ascent. If melt occurs at depth, our modeling suggests that ice‐age cycling could help it migrate upward to shallow depth or erupt, contributing to the high observed GHF. Furthermore, shallow magma emplacement might feed hydrothermal systems exploiting enhanced faulting or fracturing from ice‐age cycling, adding to elevated GHF. The preglacial passage of the Iceland‐Jan Mayen hot spot could have sourced such magmas. Direct observations of these lithospheric processes needed to further constrain our models are limited, highlighting the value of more targeted geophysical studies informing future modeling.

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Section: Discussionmentioning

confidence: 99%

Enhancement of volcanism and geothermal heat flux by ice‐age cycling: A stress modeling study of Greenland

2016

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“…The WARS is bounded to the southeast by the Ellsworth‐Whitmore block, a fragment of the margin of the East Antarctic craton that has separated, translated, and rotated into West Antarctica [ Schopf , ; Dalziel and Elliot , ; Grunow et al ., ; Randall and Mac Niocaill , ]. Marie Byrd Land, defining the complementary edge of the rift system, is an uplifted region that has undergone Paleozoic through Cenozoic magmatic activity [ Hole and LeMasurier , ; Panter et al ., ; Corr and Vaughan , ; Paulson and Wilson , ; Lough et al ., ] and shows somewhat thicker crust [ Chaput et al ., ] Recent work supports a plume hypothesis for uplift of Marie Byrd Land. Lines of evidence include igneous rocks with a geochemical plume affinity [ Weaver et al ., ; Panter et al ., ] and deep seated low‐velocity anomalies observed seismically [ Sieminski et al ., ; Hansen et al ., ].…”

Section: Tectonic Settingmentioning

confidence: 99%

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

Wiens²,

et al. 2016

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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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“…8b,c), are interpreted to be caused by a mafic dyke field related to the Cenozoic volcanic province of eastern Marie Byrd Land and western Ellsworth Land (e.g. LeMasurier, 1990;Paulsen and Wilson, 2010). Due to the presence of the nearby volcanic Hudson Mountains, one might expect volcanic,~5 km radius cone-like features on the shelf as well, but the line spacing of the survey does not allow for the unequivocal identification or clear resolution of such features.…”

Section: Superposed Tectonic Eventsmentioning

confidence: 99%

Deciphering tectonic phases of the Amundsen Sea Embayment shelf, West Antarctica, from a magnetic anomaly grid

et al. 2013

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The Amundsen Sea Embayment (ASE), with Pine Island Bay (PIB) in the eastern embayment, is a key location to understanding tectonic processes of the Pacific margin of West Antarctica. PIB has for a long time been suggested to contain the crustal boundary between the Thurston Island block and the Marie Byrd Land block. Plate tectonic reconstructions have shown that the initial rifting and breakup of New Zealand from West Antarctica occurred between Chatham Rise and the eastern Marie Byrd Land at the ASE. Recent concepts have discussed the possibility of PIB being the site of one of the eastern branches of the West Antarctic Rift System (WARS). About 30,000 km of aeromagnetic data -collected opportunistically by ship-based helicopter flights -and tracks of ship-borne magnetics were recorded over the ASE shelf during two RV Polarstern expeditions in 2006 and 2010. Grid processing, Euler deconvolution and 2D modelling were applied for the analysis of magnetic anomaly patterns, identification of structural lineaments and characterisation of magnetic source bodies. The grid clearly outlines the boundary zone between the inner shelf with outcropping basement rocks and the sedimentary basins of the middle to outer shelf. Distinct zones of anomaly patterns and lineaments can be associated with at least three tectonic phases from (1) magmatic emplacement zones of Cretaceous rifting and breakup (100-85 Ma), to (2) a southern distributed plate boundary zone of the Bellingshausen Plate (80-61 Ma) and (3) activities of the WARS indicated by NNE-SSW trending lineaments (55-30 Ma?). The analysis and interpretation are also used for constraining the directions of some of the flow paths of past grounded ice streams across the shelf.

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Evolution of Neogene volcanism and stress patterns in the glaciated West Antarctic Rift, Marie Byrd Land, Antarctica

Cited by 18 publications

References 89 publications

Enhancement of volcanism and geothermal heat flux by ice‐age cycling: A stress modeling study of Greenland

Enhancement of volcanism and geothermal heat flux by ice‐age cycling: A stress modeling study of Greenland

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

Deciphering tectonic phases of the Amundsen Sea Embayment shelf, West Antarctica, from a magnetic anomaly grid

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