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Architecture of North Atlantic contourite drifts modified by transient circulation of the Icelandic mantle plume

Architecture of North Atlantic contourite drifts modified by transient circulation of the Icelandic mantle plume
Architecture of North Atlantic contourite drifts modified by transient circulation of the Icelandic mantle plume
Overflow of Northern Component Water, the precursor of North Atlantic Deep Water, appears to have varied during Neogene times. It has been suggested that this variation is moderated by transient behavior of the Icelandic mantle plume, which has influenced North Atlantic bathymetry through time. Thus pathways and intensities of bottom currents that control deposition of contourite drifts could be affected by mantle processes. Here, we present regional seismic reflection profiles that cross sedimentary accumulations (Björn, Gardar, Eirik, and Hatton Drifts). Prominent reflections were mapped and calibrated using a combination of boreholes and legacy seismic profiles. Interpreted seismic profiles were used to reconstruct solid sedimentation rates. Björn Drift began to accumulate in late Miocene times. Its average sedimentation rate decreased at ?2.5 Ma and increased again at ?0.75 Ma. In contrast, Eirik Drift started to accumulate in early Miocene times. Its average sedimentation rate increased at ?5.5 Ma and decreased at ?2.2 Ma. In both cases, there is a good correlation between sedimentation rates, inferred Northern Component Water overflow, and the variation of Icelandic plume temperature independently obtained from the geometry of diachronous V-shaped ridges. Between 5.5 and 2.5 Ma, the plume cooled, which probably caused subsidence of the Greenland-Iceland-Scotland Ridge, allowing drift accumulation to increase. When the plume became hotter at 2.5 Ma, drift accumulation rate fell. We infer that deep-water current strength is modulated by fluctuating dynamic support of the Greenland-Scotland Ridge. Our results highlight the potential link between mantle convective processes and ocean circulation.
contourite, drift, Iceland, plume
1525-2027
3414-3435
Parnell-Turner, Ross
c36e10be-a5dd-4052-b57c-6fe887f66540
White, Nicholas J.
d98712dc-9d5d-468e-8f9b-d8893d0b3f6d
McCave, I. Nick
3411a57a-d784-4bfb-9c84-da107426e36f
Henstock, Timothy J.
27c450a4-3e6b-41f8-97f9-4e0e181400bb
Murton, Bramley
9076d07f-a3c1-4f90-a5d5-99b27fe2cb12
Jones, Stephen M.
ea872e90-f80c-4cb6-9edd-4c2b4cc4867a
Parnell-Turner, Ross
c36e10be-a5dd-4052-b57c-6fe887f66540
White, Nicholas J.
d98712dc-9d5d-468e-8f9b-d8893d0b3f6d
McCave, I. Nick
3411a57a-d784-4bfb-9c84-da107426e36f
Henstock, Timothy J.
27c450a4-3e6b-41f8-97f9-4e0e181400bb
Murton, Bramley
9076d07f-a3c1-4f90-a5d5-99b27fe2cb12
Jones, Stephen M.
ea872e90-f80c-4cb6-9edd-4c2b4cc4867a

Parnell-Turner, Ross, White, Nicholas J., McCave, I. Nick, Henstock, Timothy J., Murton, Bramley and Jones, Stephen M. (2015) Architecture of North Atlantic contourite drifts modified by transient circulation of the Icelandic mantle plume. Geochemistry, Geophysics, Geosystems, 16 (10), 3414-3435. (doi:10.1002/2015GC005947).

Record type: Article

Abstract

Overflow of Northern Component Water, the precursor of North Atlantic Deep Water, appears to have varied during Neogene times. It has been suggested that this variation is moderated by transient behavior of the Icelandic mantle plume, which has influenced North Atlantic bathymetry through time. Thus pathways and intensities of bottom currents that control deposition of contourite drifts could be affected by mantle processes. Here, we present regional seismic reflection profiles that cross sedimentary accumulations (Björn, Gardar, Eirik, and Hatton Drifts). Prominent reflections were mapped and calibrated using a combination of boreholes and legacy seismic profiles. Interpreted seismic profiles were used to reconstruct solid sedimentation rates. Björn Drift began to accumulate in late Miocene times. Its average sedimentation rate decreased at ?2.5 Ma and increased again at ?0.75 Ma. In contrast, Eirik Drift started to accumulate in early Miocene times. Its average sedimentation rate increased at ?5.5 Ma and decreased at ?2.2 Ma. In both cases, there is a good correlation between sedimentation rates, inferred Northern Component Water overflow, and the variation of Icelandic plume temperature independently obtained from the geometry of diachronous V-shaped ridges. Between 5.5 and 2.5 Ma, the plume cooled, which probably caused subsidence of the Greenland-Iceland-Scotland Ridge, allowing drift accumulation to increase. When the plume became hotter at 2.5 Ma, drift accumulation rate fell. We infer that deep-water current strength is modulated by fluctuating dynamic support of the Greenland-Scotland Ridge. Our results highlight the potential link between mantle convective processes and ocean circulation.

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Accepted/In Press date: October 2015
Published date: October 2015
Keywords: contourite, drift, Iceland, plume
Organisations: Geology & Geophysics, Marine Geoscience

Identifiers

Local EPrints ID: 383040
URI: http://eprints.soton.ac.uk/id/eprint/383040
ISSN: 1525-2027
PURE UUID: a584c023-1513-4b0e-9e1e-9cdfe6b05075
ORCID for Timothy J. Henstock: ORCID iD orcid.org/0000-0002-2132-2514

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Date deposited: 19 Oct 2015 12:31
Last modified: 15 Mar 2024 03:04

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Contributors

Author: Ross Parnell-Turner
Author: Nicholas J. White
Author: I. Nick McCave
Author: Bramley Murton
Author: Stephen M. Jones

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