Architecture of North Atlantic Contourite Drifts Modified by Transient Circulation of the Icelandic Mantle Plume

Parnell-Turner, Ross and White, N. J. and McCave, I. Nick and Henstock, Tim and 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. ISSN 1525-2027 DOI 10.1002/2015GC005947 (In Press)

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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.

Item Type: Article
Uncontrolled Keywords: 2015AREP; IA69;
Subjects: 02 - Geodynamics, Geophysics and Tectonics
Divisions: 02 - Geodynamics, Geophysics and Tectonics
08 - Green Open Access
Journal or Publication Title: Geochemistry Geophysics Geosystems
Identification Number: 10.1002/2015GC005947
Depositing User: Sarah Humbert
Date Deposited: 23 Sep 2015 10:08
Last Modified: 29 Sep 2015 15:59
URI: http://eprints.esc.cam.ac.uk/id/eprint/3495

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