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dc.contributor.authorHoggard, Marken
dc.contributor.authorWhite, Nicholasen
dc.contributor.authorAl-Attar, Daviden
dc.date.accessioned2017-05-11T08:57:28Z
dc.date.available2017-05-11T08:57:28Z
dc.date.issued2016-06en
dc.identifier.issn1752-0908
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/264180
dc.description.abstractConvective circulation of the Earth’s mantle maintains some fraction of surface topography that varies with space and time. Most predictive models show that this dynamic topography has peak amplitudes of about ±2 km, dominated by wavelengths of 104 km. Here, we test these models against our comprehensive observational database of 2,120 spot measurements of dynamic topography that were determined by analysing oceanic seismic surveys. These accurate measurements have typical peak amplitudes of ±1 km and wavelengths of approximately 103 km, and are combined with limited continental constraints to generate a global spherical harmonic model, the robustness of which has been carefully tested and benchmarked. Our power spectral analysis reveals significant discrepancies between observed and predicted dynamic topography. At longer wavelengths (such as 104 km), observed dynamic topography has peak amplitudes of about ±500 m. At shorter wavelengths (such as 103 km), significant dynamic topography is still observed. We show that these discrepancies can be explained if short-wavelength dynamic topography is generated by temperature-driven density anomalies within a sub-plate asthenospheric channel. Stratigraphic observations from adjacent continental margins show that these dynamic topographic signals evolve quickly with time. More rapid temporal and spatial changes in vertical displacement of the Earth’s surface have direct consequences for fields as diverse as mantle flow, oceanic circulation and long-term climate change.
dc.description.sponsorshipThis research was supported by a BP-Cambridge collaboration. We are grateful to ION for permission to publish partial seismic reflection profiles shown in Fig. 2 from their IndiaSPAN and Greater BrasilSPAN data sets.
dc.language.isoenen
dc.publisherNature Publishing Group
dc.titleGlobal dynamic topography observations reveal limited influence of large-scale mantle flowen
dc.typeArticle
prism.endingPage463
prism.issueIdentifier6en
prism.publicationDate2016en
prism.publicationNameNature Geoscienceen
prism.startingPage456
prism.volume9en
dc.identifier.doi10.17863/CAM.9538
dcterms.dateAccepted2016-04-05en
rioxxterms.versionofrecord10.1038/ngeo2709en
rioxxterms.versionAMen
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2016-06en
dc.contributor.orcidHoggard, Mark [0000-0003-4310-3862]
dc.identifier.eissn1752-0908
rioxxterms.typeJournal Article/Reviewen
cam.issuedOnline2016-05-09en
rioxxterms.freetoread.startdate2016-11-09


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