Iceland, the Farallon slab, and dynamic topography of the North Atlantic
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 cau...
Main Authors: | , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
GEOLOGICAL SOC AMERICA, INC
2004
|
Subjects: | |
Online Access: | http://discovery.ucl.ac.uk/130797/ |
id |
ftucl:oai:eprints.ucl.ac.uk.OAI2:130797 |
---|---|
record_format |
openpolar |
spelling |
ftucl:oai:eprints.ucl.ac.uk.OAI2:130797 2023-05-15T16:47:18+02:00 Iceland, the Farallon slab, and dynamic topography of the North Atlantic Conrad, CP Lithgow-Bertelloni, C Louden, KE 2004-03 http://discovery.ucl.ac.uk/130797/ unknown GEOLOGICAL SOC AMERICA, INC GEOLOGY , 32 (3) 177 - 180. (2004) dynamic topography seafloor depth mantle flow North Atlantic Iceland Azores Scotian Basin CONTINENTAL INTERIORS MANTLE HETEROGENEITY DEEP MANTLE HEAT-FLOW MODEL PLATE DEPTH CONVECTION OCEAN AGE Article 2004 ftucl 2016-01-15T03:11:27Z 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. Article in Journal/Newspaper Iceland North Atlantic University College London: UCL Discovery Mid-Atlantic Ridge |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
unknown |
topic |
dynamic topography seafloor depth mantle flow North Atlantic Iceland Azores Scotian Basin CONTINENTAL INTERIORS MANTLE HETEROGENEITY DEEP MANTLE HEAT-FLOW MODEL PLATE DEPTH CONVECTION OCEAN AGE |
spellingShingle |
dynamic topography seafloor depth mantle flow North Atlantic Iceland Azores Scotian Basin CONTINENTAL INTERIORS MANTLE HETEROGENEITY DEEP MANTLE HEAT-FLOW MODEL PLATE DEPTH CONVECTION OCEAN AGE Conrad, CP Lithgow-Bertelloni, C Louden, KE Iceland, the Farallon slab, and dynamic topography of the North Atlantic |
topic_facet |
dynamic topography seafloor depth mantle flow North Atlantic Iceland Azores Scotian Basin CONTINENTAL INTERIORS MANTLE HETEROGENEITY DEEP MANTLE HEAT-FLOW MODEL PLATE DEPTH CONVECTION OCEAN AGE |
description |
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. |
format |
Article in Journal/Newspaper |
author |
Conrad, CP Lithgow-Bertelloni, C Louden, KE |
author_facet |
Conrad, CP Lithgow-Bertelloni, C Louden, KE |
author_sort |
Conrad, CP |
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 |
publisher |
GEOLOGICAL SOC AMERICA, INC |
publishDate |
2004 |
url |
http://discovery.ucl.ac.uk/130797/ |
geographic |
Mid-Atlantic Ridge |
geographic_facet |
Mid-Atlantic Ridge |
genre |
Iceland North Atlantic |
genre_facet |
Iceland North Atlantic |
op_source |
GEOLOGY , 32 (3) 177 - 180. (2004) |
_version_ |
1766037387588141056 |