Iceland, the Farallon slab, and dynamic topography of the North Atlantic
ABSTRACT Upwelling or downwelling flow in Earth's mantle is thought to elevate or depress Earth's surface on a continental scale. Direct observation of this ''dynamic topography'' on the seafloor, however, has remained elusive because it is obscured by isostatically sup...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.1044.7132 2023-05-15T16:48:09+02:00 Iceland, the Farallon slab, and dynamic topography of the North Atlantic Clinton P Conrad Carolina Lithgow-Bertelloni Keith E Louden The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1044.7132 http://www.soest.hawaii.edu/GG/FACULTY/conrad/papers/Conrad_Geology2004.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1044.7132 http://www.soest.hawaii.edu/GG/FACULTY/conrad/papers/Conrad_Geology2004.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.soest.hawaii.edu/GG/FACULTY/conrad/papers/Conrad_Geology2004.pdf text ftciteseerx 2020-04-05T00:16:28Z ABSTRACT Upwelling or downwelling flow in Earth's mantle is thought to elevate or depress Earth's surface on a continental scale. Direct observation of this ''dynamic topography'' on the seafloor, however, has remained elusive because it is obscured by isostatically supported topography caused by near-surface density variations. We calculate the nonisostatic topography of the North Atlantic by correcting seafloor depths for lithospheric cooling and sediment loading, and find that seafloor west of the Mid-Atlantic Ridge is an average of 0.5 km deeper than it is to the east. We are able to reproduce this basic observation in a model of mantle flow driven by tomographically inferred mantle densities. This model shows that the Farallon slab, currently in the lower mantle beneath the east coast of North America, induces downwelling flow that deepens the western North Atlantic relative to the east. Our model also predicts dynamic support of observed topographic highs near Iceland and the Azores, but suggests that the Icelandic high is due to local upper-mantle upwelling, while the Azores high is part of a plate-scale lower-mantle upwelling to the south. An anomalously deep area off the coast of Nova Scotia may be associated with the downwelling component of edge-driven convection at the continental boundary. Thus, several of the seafloor's topographic features can only be understood in terms of dynamic support from flow in Earth's mantle. Text Iceland North Atlantic Unknown Mid-Atlantic Ridge |
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English |
description |
ABSTRACT Upwelling or downwelling flow in Earth's mantle is thought to elevate or depress Earth's surface on a continental scale. Direct observation of this ''dynamic topography'' on the seafloor, however, has remained elusive because it is obscured by isostatically supported topography caused by near-surface density variations. We calculate the nonisostatic topography of the North Atlantic by correcting seafloor depths for lithospheric cooling and sediment loading, and find that seafloor west of the Mid-Atlantic Ridge is an average of 0.5 km deeper than it is to the east. We are able to reproduce this basic observation in a model of mantle flow driven by tomographically inferred mantle densities. This model shows that the Farallon slab, currently in the lower mantle beneath the east coast of North America, induces downwelling flow that deepens the western North Atlantic relative to the east. Our model also predicts dynamic support of observed topographic highs near Iceland and the Azores, but suggests that the Icelandic high is due to local upper-mantle upwelling, while the Azores high is part of a plate-scale lower-mantle upwelling to the south. An anomalously deep area off the coast of Nova Scotia may be associated with the downwelling component of edge-driven convection at the continental boundary. Thus, several of the seafloor's topographic features can only be understood in terms of dynamic support from flow in Earth's mantle. |
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The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Clinton P Conrad Carolina Lithgow-Bertelloni Keith E Louden |
spellingShingle |
Clinton P Conrad Carolina Lithgow-Bertelloni Keith E Louden Iceland, the Farallon slab, and dynamic topography of the North Atlantic |
author_facet |
Clinton P Conrad Carolina Lithgow-Bertelloni Keith E Louden |
author_sort |
Clinton P Conrad |
title |
Iceland, the Farallon slab, and dynamic topography of the North Atlantic |
title_short |
Iceland, the Farallon slab, and dynamic topography of the North Atlantic |
title_full |
Iceland, the Farallon slab, and dynamic topography of the North Atlantic |
title_fullStr |
Iceland, the Farallon slab, and dynamic topography of the North Atlantic |
title_full_unstemmed |
Iceland, the Farallon slab, and dynamic topography of the North Atlantic |
title_sort |
iceland, the farallon slab, and dynamic topography of the north atlantic |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1044.7132 http://www.soest.hawaii.edu/GG/FACULTY/conrad/papers/Conrad_Geology2004.pdf |
geographic |
Mid-Atlantic Ridge |
geographic_facet |
Mid-Atlantic Ridge |
genre |
Iceland North Atlantic |
genre_facet |
Iceland North Atlantic |
op_source |
http://www.soest.hawaii.edu/GG/FACULTY/conrad/papers/Conrad_Geology2004.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1044.7132 http://www.soest.hawaii.edu/GG/FACULTY/conrad/papers/Conrad_Geology2004.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766038267342356480 |