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A review of observations and models of dynamic topography

Flament, Nicolas and Gurnis, Michael and Müller, R. Dietmar (2013) A review of observations and models of dynamic topography. Lithosphere, 5 (2). pp. 189-210. ISSN 1941-8264. http://resolver.caltech.edu/CaltechAUTHORS:20130906-134006753

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Abstract

The topography of Earth is primarily controlled by lateral differences in the density structure of the crust and lithosphere. In addition to this isostatic topography, flow in the mantle induces deformation of its surface leading to dynamic topography. This transient deformation evolves over tens of millions of years, occurs at long wavelength, and is relatively small (<2 km) in amplitude. Here, we review the observational constraints and modeling approaches used to understand the amplitude, spatial pattern, and time dependence of dynamic topography. The best constraint on the present-day dynamic topography induced by sublithospheric mantle flow is likely the residual bathymetry calculated by removing the isostatic effect of oceanic lithospheric structure from observed bathymetry. Increasing knowledge of the thermal and chemical structure of the lithosphere is important to better constrain present-day mantle flow and dynamic topography. Nevertheless, at long wavelengths (>5000 km), we show that there is good agreement between published residual topography fields, including the one described here, and present-day dynamic topography predicted from mantle flow models, including a new one. Residual and predicted fields show peak-to-peak amplitudes of roughly ±2 km and a dominant degree two pattern with high values for the Pacific Ocean, southern Africa, and the North Atlantic and low values for South America, western North America, and Eurasia. The flooding of continental interiors has long been known to require both larger amplitudes and to be temporally phase-shifted compared with inferred eustatic changes. Such long-wavelength inferred vertical motions have been attributed to dynamic topography. An important consequence of dynamic topography is that long-term global sea-level change cannot be estimated at a single passive margin. As a case study, we compare the results of three published models and of our model to the subsidence history of well COST-B2 offshore New Jersey. The <400 ± 45 m amount of anomalous subsidence of this well since 85 Ma is best explained by models that predict dynamic subsidence of the New Jersey margin during that period. Explicitly including the lithosphere in future global mantle flow models should not only facilitate such comparisons between model results and data, but also further constrain the nature of the coupling between the mantle and the lithosphere.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1130/L245.1 DOIArticle
http://lithosphere.gsapubs.org/content/5/2/189PublisherArticle
http://lithosphere.geoscienceworld.org/content/5/2/189PublisherArticle
ORCID:
AuthorORCID
Gurnis, Michael0000-0003-1704-597X
Müller, R. Dietmar0000-0002-3334-5764
Additional Information:© 2012 Geological Society of America. Manuscript Received 13 July 2012; Revised manuscript received 7 November 2012; Manuscript accepted 27 November 2012. We thank C. Conrad, Y. Ricard, S. Spasojevic, and B. Steinberger for sharing their results, M. Kominz for the updated COST-B2 well data, and L. Husson for discussions. This paper benefi ted from comments by two anonymous reviewers. Flament was supported by Statoil, Gurnis by the National Science Foundation (through EAR-0810303) and the Caltech Tectonics Observatory (by the Gordon and Betty Moore Foundation), and Müller by Australian Research Council grant FL0992245. Computer simulations were carried out on the Sun Constellation VAYU Cluster of the Australian National Computational Infrastructure. Figures 1, 4, and 7 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). This is contribution 216 of the Caltech Tectonics Observatory.
Group:Caltech Tectonics Observatory, Seismological Laboratory
Funders:
Funding AgencyGrant Number
StatoilUNSPECIFIED
NSFEAR-0810303
Caltech Tectonics ObservatoryUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Australian Research CouncilFL0992245
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory216
Record Number:CaltechAUTHORS:20130906-134006753
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20130906-134006753
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41146
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:17 Sep 2013 20:57
Last Modified:24 Oct 2017 19:55

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