EGU2020-10110
https://doi.org/10.5194/egusphere-egu2020-10110
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Drilling the Tore seamount- Archive of a natural oceanic sediment trap

Susana M. Lebreiro1, Silvia Nave2, Laura Antón1, Elizabeth Michel3, Catherine Kissel3, Claire Waelbroeck3, Nick McCave4, David Hodell4, Jose-Abel Flores5, Francisca Martinez-Ruiz6, Belén Martrat7, Cristina Roque8, Alex Piotrowski4, Luke Skinner4, Francisco Sierro5, Pedro Terrinha8, Guy Cornen9, María Isabel Reguera1, Rocío Lozano-Luz1, and Natalia Bravo1
Susana M. Lebreiro et al.
  • 1Instituto Geológico y Minero de España, Madrid, Spain (susana.lebreiro@igme.es)
  • 2Laboratorio Nacional Energia e Geologia, Alfragide, Portugal
  • 3Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette , France
  • 4Godwin Laboratory, University of Cambridge, Cambridge, United Kingdom
  • 5University of Salamanca, Salamanca, Spain
  • 6Instituto Andaluz de Ciencias de la Tierra-CSIC, Universidad de Granada, Granada, Spain
  • 7Institute of Environmental Assessment and Water Research-CSIC, Barcelona, Spain
  • 8Instituto Português do Mar e Atmosfera, Lisboa, Portugal
  • 9University of Nantes, Nantes, France

Located 300 km off West Iberia in the open NE Atlantic Ocean, the Tore seamount emerges from the 5.5 km surrounding abyssal plains to a summit rim at 2.2 km, which has an elliptical crater-like shape with a central depression 100 km in diameter. The ~5.5 km depth of the Tore internal basin is connected to the surrounding deep ocean basin by a single narrow gateway down to 4.3 km depth. This basin is exceptional because it is 1) a giant sediment-trap for vertical fluxes, with sediments unaffected by deep currents and erosion, containing a record of enhanced biogenic subtropical productivity during deglaciations, which can be examined mechanistically, 2) a natural laboratory to examine carbonate dissolution at 5.5 km water depth constrained by NADW deep ventilation during glacials, and 3) an excellent location to test sediment processes distant from continental margins and understand triggering mechanisms of downslope flows in the open, deep ocean. Not many cores have been recovered in the area at such 5.5 km depth and unite this singular environment. At the larger scale of North Atlantic circulation and productivity, the semi-isolated Tore seamount is a most valuable site to assess crucial scientific hypotheses related to thermohaline circulation, carbon cycling and climate variability. These challenging questions are framed in the IODP Initial Science Plan illuminating Earth´s Past, Present and Future, 2013-2023, theme Climate and Ocean Change.

Our APL applies for drilling one site in the middle of the Tore seamount at 5.5 km depth, to retrieve a complete Quaternary sedimentary sequence (180 m long). This carbonate rich archive will be compared with records available in the Northeast Atlantic and to be recovered during Expedition #771-Full2 (Hodell et al.).

We present results from a 24 long giant Calypso core taken in the APL-site proposed which covers 430 thousand years and 5 glacial-interglacial cycles (Spanish project “TORE5deglaciations”, CTM2017-84113-R, 2018-2020).

How to cite: Lebreiro, S. M., Nave, S., Antón, L., Michel, E., Kissel, C., Waelbroeck, C., McCave, N., Hodell, D., Flores, J.-A., Martinez-Ruiz, F., Martrat, B., Roque, C., Piotrowski, A., Skinner, L., Sierro, F., Terrinha, P., Cornen, G., Reguera, M. I., Lozano-Luz, R., and Bravo, N.: Drilling the Tore seamount- Archive of a natural oceanic sediment trap, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10110, https://doi.org/10.5194/egusphere-egu2020-10110, 2020

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