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| Titel |
Diverse Manifestations of Convective Upwelling Beneath the North Atlantic Ocean |
| VerfasserIn |
Nicky White, Ross Parnell-Turner |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250078782
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| Zusammenfassung |
| The Icelandic Plume dominates the North Atlantic Ocean. Residual depth anomalies of
oceanic lithosphere, long wavelength gravity anomalies, and seismic tomographic models
show that this large upwelling reaches from Baffin Bay to Western Norway, and from
offshore Newfoundland to Spitzbergen. At continental margins, there is excellent evidence
for present-day dynamic support of crust beneath Scotland and Western Norway. It is
generally agreed that the Icelandic Plume started at 62 Ma. In recent years, a quantitative
understanding of the temporal evolution of this upwelling has begun to emerge.
The best evidence occurs in the oceanic basins north and south of Iceland. Since
the mid-oceanic ridge straddles the plume, it acts as a linear sampler of transient
activity over the last 40–50 Ma. A pair of seismic reflection flowlines acquired in
2010 have enabled us to determine the detailed history of transient activity. The
implications of this history are profound. Waxing and waning of convective upwelling
beneath this important oceanic gateway appears to have modulated the overflow
of the ancient precursor to North Atlantic Deep Water (NADW). The growth of
contourite drifts which plaster deep-water margins can also be directly linked to
changing vertical motions at this gateway. Finally, there is increasing evidence that the
otherwise uniform thermal subsidence of sedimentary basins, which fringe both sides
of the North Atlantic Ocean, has been periodically interrupted by transient uplift
events which generated ephemeral landscapes. These geologic manifestations of
convective activity should lead to improved insights into the fluid dynamics of the
mantle. |
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