EGU2020-5873, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-5873
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Variation of the tectono-magmatic activity along the Reykjanes Ridge: Influence of the Iceland hotspot on the accretionary processes

Morgane Le Saout1, Colin Devey1, Dominik Palgan2, Thorsten Lux1, Sven Petersen1, Daníel Þórhallsson3, Adrianna Tomkowicz2, and Saskia Brix4
Morgane Le Saout et al.
  • 1GEOMAR, Helmholtz Centre for Ocean Research Kiel, Germany
  • 2Institute of Oceanography, University of Gdańsk, Poland
  • 3Institute of Biology, University of Iceland,Reykjavík, Iceland
  • 4Senckenberg am Meer, German Centre for Marine Biodiversity Research (DZMB), Hamburg, Germany

The Reykjanes Ridge is a 900 km long oblique slow-spreading ridge, formed by individual “en echelon” axial volcanic ridges (AVR), directly under the influence of the Iceland hotspot. From the Reykjanes Peninsula to the Bight fracture zone, the Reykjanes Ridge shows variations in lava chemistry, crustal thickness, thermal structure and ridge morphology, which has been attributed to this influence. Our study focuses on four areas of the ridge mapped and sampled during the cruise MSM75 in 2018. The northern area is characterized by the only known hydrothermal field discovered along the Reykjanes Ridge. The two central areas are located in a region of increasing magma supply. Finally, the southernmost area is underlined by the only magma body ever detected seismically below the Reykjanes Ridge. The analysis combines 15 m resolution ship-based bathymetry, ground-truthing from ROV dives and geochemical analysis of glass samples to look at variations of magma composition, fault density, seamount density and morphology along the ridge axis. Two major parameters influence the distribution and geometry of faults and seamounts: the distance from the hotspot and the accretion state of individual AVR (i.e., magmatic extension vs. tectonic extension). Fracture geometry is highly influenced by the depth of the brittle-ductile boundary that deepens with distance from the plume center, while fault density at the axis reflects different development stages of individual AVR. Seamount morphologies may also reflect individual AVR development, but we also show morphological variation with distance from the hotspot, correlated with the average variation in lava composition and mantle temperature.

How to cite: Le Saout, M., Devey, C., Palgan, D., Lux, T., Petersen, S., Þórhallsson, D., Tomkowicz, A., and Brix, S.: Variation of the tectono-magmatic activity along the Reykjanes Ridge: Influence of the Iceland hotspot on the accretionary processes, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5873, https://doi.org/10.5194/egusphere-egu2020-5873, 2020

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