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Influence of subduction history on South American topography

Flament, Nicolas and Gurnis, Michael and Müller, R. Dietmar and Bower, Dan J. and Husson, Laurent (2015) Influence of subduction history on South American topography. Earth and Planetary Science Letters, 430 . pp. 9-18. ISSN 0012-821X. http://resolver.caltech.edu/CaltechAUTHORS:20151112-133834418

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Abstract

The Cenozoic evolution of South American topography is marked by episodes of large-scale uplift and subsidence not readily explained by lithospheric deformation. The drying up of the inland Pebas system, the drainage reversal of the Amazon river, the uplift of the Sierras Pampeanas and the uplift of Patagonia have all been linked to the evolution of mantle flow since the Miocene in separate studies. Here we investigate the evolution of long-wavelength South American topography as a function of subduction history in a time-dependent global geodynamic model. This model is shown to be consistent with these inferred changes, as well as with the migration of the Chaco foreland basin depocentre, that we partly attribute to the inboard migration of subduction resulting from Andean mountain building. We suggest that the history of subduction along South America has had an important influence on the evolution of the topography of the continent because time-dependent mantle flow models are consistent with the history of vertical motions as constrained by the geological record at four distant areas over a whole continent. Testing alternative subduction scenarios reveals flat slab segments are necessary to reconcile inferred Miocene shorelines with a simple model paleogeography. As recently suggested, we find that the flattening of a subduction zone results in dynamic uplift between the leading edge of the flat slab segment and the trench, and in a wave of dynamic subsidence associated with the inboard migration of the leading edge of flat subduction. For example, the flattening of the Peruvian subduction contributed to the demise of Pebas shallow-water sedimentation, while continental-scale tilting also contributed to the drainage reversal of the Amazon River. The best correlation to P-wave tomography models for the Peruvian flat slab segment is obtained for a case when the asthenosphere, here considered to be 150 km thick and 10 times less viscous than the upper mantle, is restricted to the oceanic domain.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.epsl.2015.08.006DOIArticle
http://www.sciencedirect.com/science/article/pii/S0012821X15005208PublisherArticle
ORCID:
AuthorORCID
Gurnis, Michael0000-0003-1704-597X
Müller, R. Dietmar0000-0002-3334-5764
Additional Information:© 2015 Elsevier B.V. Received 20 June 2015; Received in revised form 7 August 2015; Accepted 8 August 2015; Available online 24 August 2015. N.F. and R.D.M. were supported by Statoil ASA through ARC IH130200012, M.G. and D.J.B. were supported by Statoil ASA and by the NSF (through EAR-1161046 and EAR-1247022). This re-search was undertaken with the assistance of resources from the National Computational Infrastructure (NCI), which is supported by the Australian Government. We thank Simon Williams for comments on an early version of the manuscript, and F. Davila and an anonymous reviewer for constructive comments that improved the manuscript. The evolution of the dynamic topography predicted by all four cases for South America since 50 Ma is available at http://www.earthbyte.org/resources.html.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
Australian Research CouncilIH130200012
Statoil ASAUNSPECIFIED
NSFEAR-1161046
NSFEAR-1247022
Australian GovernmentUNSPECIFIED
Subject Keywords:South America; paleogeography; topography; mantle flow; flat subduction; dynamic topography
Record Number:CaltechAUTHORS:20151112-133834418
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20151112-133834418
Official Citation:Nicolas Flament, Michael Gurnis, R. Dietmar Müller, Dan J. Bower, Laurent Husson, Influence of subduction history on South American topography, Earth and Planetary Science Letters, Volume 430, 15 November 2015, Pages 9-18, ISSN 0012-821X, http://dx.doi.org/10.1016/j.epsl.2015.08.006. (http://www.sciencedirect.com/science/article/pii/S0012821X15005208)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:62074
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:18 Nov 2015 18:12
Last Modified:24 Oct 2017 19:49

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