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Topographic asymmetry of the South Atlantic from global models of mantle flow and lithospheric stretching

Flament, Nicolas and Gurnis, Michael and Williams, Simon and Seton, Maria and Skogseid, Jakob and Heine, Christian and Müller, R. Dietmar (2014) Topographic asymmetry of the South Atlantic from global models of mantle flow and lithospheric stretching. Earth and Planetary Science Letters, 387 . pp. 107-119. ISSN 0012-821X. http://resolver.caltech.edu/CaltechAUTHORS:20140313-074424127

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Abstract

The relief of the South Atlantic is characterized by elevated passive continental margins along southern Africa and eastern Brazil, and by the bathymetric asymmetry of the southern oceanic basin where the western flank is much deeper than the eastern flank. We investigate the origin of these topographic features in the present and over time since the Jurassic with a model of global mantle flow and lithospheric deformation. The model progressively assimilates plate kinematics, plate boundaries and lithospheric age derived from global tectonic reconstructions with deforming plates, and predicts the evolution of mantle temperature, continental crustal thickness, long-wavelength dynamic topography, and isostatic topography. Mantle viscosity and the kinematics of the opening of the South Atlantic are adjustable parameters in thirteen model cases. Model predictions are compared to observables both for the present-day and in the past. Present-day predictions are compared to topography, mantle tomography, and an estimate of residual topography. Predictions for the past are compared to tectonic subsidence from backstripped borehole data along the South American passive margin, and to dynamic uplift as constrained by thermochronology in southern Africa. Comparison between model predictions and observations suggests that the first-order features of the topography of the South Atlantic are due to long-wavelength dynamic topography, rather than to asthenospheric processes. The uplift of southern Africa is best reproduced with a lower mantle that is at least 40 times more viscous than the upper mantle.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.epsl.2013.11.017DOIArticle
http://www.sciencedirect.com/science/article/pii/S0012821X13006511PublisherArticle
ORCID:
AuthorORCID
Gurnis, Michael0000-0003-1704-597X
Skogseid, Jakob0000-0002-6817-7756
Müller, R. Dietmar0000-0002-3334-5764
Additional Information:© 2013 Elsevier B.V. Received 20 June 2013. Received in revised form 15 October 2013. Accepted 11 November 2013. Available online 6 December 2013. Editor: Y. Ricard. N.F. was supported by Statoil ASA, M.G. was partially supported by Statoil ASA and by the National Science Foundation under grants CMMI-1028978, EAR-1161046 and EAR-1247022, S.W. and R.D.M. were supported by Australian Research Council (ARC) grant FL0992245, M.S. was supported by ARC grant DP0987713, and C.H. was supported by ARC grant LP0989312. Computer simulations were carried out on the Sun Constellation VAYU cluster of the Australian National Computational Infrastructure. Fig. 1, Fig. 4, Fig. 5, Fig. 6, Fig. 7 and Fig. 8A–D were prepared using the Generic Mapping Tools (Wessel and Smith, 1998). The original CitcomS software was obtained from CIG, Computational Infrastructure for Geodynamics (http://geodynamics.org). We thank L. Husson and an anonymous reviewer for their detailed and constructive comments.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
Statoil ASAUNSPECIFIED
NSFCMMI-1028978
NSFEAR-1161046
NSFEAR-1247022
Australian Research CouncilFL0992245
Australian Research CouncilDP0987713
Australian Research CouncilLP0989312
Subject Keywords:South Atlantic; dynamic topography; topography; tectonic reconstructions; mantle flow; rifting
Record Number:CaltechAUTHORS:20140313-074424127
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140313-074424127
Official Citation:Nicolas Flament, Michael Gurnis, Simon Williams, Maria Seton, Jakob Skogseid, Christian Heine, R. Dietmar Müller, Topographic asymmetry of the South Atlantic from global models of mantle flow and lithospheric stretching, Earth and Planetary Science Letters, Volume 387, 1 February 2014, Pages 107-119, ISSN 0012-821X, http://dx.doi.org/10.1016/j.epsl.2013.11.017. (http://www.sciencedirect.com/science/article/pii/S0012821X13006511)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44288
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:13 Mar 2014 15:44
Last Modified:15 Nov 2017 00:06

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