EGU21-12712
https://doi.org/10.5194/egusphere-egu21-12712
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Morphological rejuvenation on tectonic seamounts: insights from the Gorringe Bank, SW Iberian Margin

Davide Gamboa1, Rachid Omira1,2, Aldina Piedade1, Pedro Terrinha1,2, Cristina Roque2,3, and Nevio Zitellini4
Davide Gamboa et al.
  • 1Instituto Português do Mar e de Atmosfera – IPMA, I.P.; Rua C do Aeroporto, 1749-077 Lisbon, Portugal
  • 2Instituto D. Luiz – IDL; Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Edifício C8, Piso 3, 1749-016 Lisbon, Portugal
  • 3Estrutura de Missão de Extensão da Plataforma Continental – EMEPC; Rua Costa Pinto, n. 165, 2770-047 Paço de Arcos, Portugal
  • 4Istituto di Scienze Marine (ISMAR), Via Gobetti 101, 40129, Bologna, Italy

Seamounts are spectacular bathymetric features common within volcanic and tectonically active continental margins. During their lifecycles, they evolve through stages of construction and destruction. Seamount chains on the Southwest Iberian Margin are prone to instability and collapse due to regionally complex tectonism with moderate to high seismicity. In this work we investigate collapse episodes during the lifecycle of the tectonic Gorringe Bank (GB), the largest submarine seamount offshore European margins, based on recurrence patterns of MTDs on the active thrust flank. Eight MTDs with relevant expression on the seismic data were analysed, four of estimated Miocene age and four on a Pliocene-Quarternary interval. Miocene MTDs are overall larger and correlate with the main uplift stages of the GB structure. Their distribution and relative timing suggest that failure-triggering earthquakes were common along the whole length of the GB. Pliocene to Quarternary MTDs tend to cluster along the northern half of the GB flank and are generally smaller. Based on our observations, we propose that the lifecycle of tectonic seamounts is marked by morphological rejuvenation episodes driven by tectonic activity between major collapse events or cycles. Tectonic-driven rejuvenation is thus key to hinder or obliterate evidence of past high-magnitude destructive events on tectonic seamount morphology.

How to cite: Gamboa, D., Omira, R., Piedade, A., Terrinha, P., Roque, C., and Zitellini, N.: Morphological rejuvenation on tectonic seamounts: insights from the Gorringe Bank, SW Iberian Margin, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12712, https://doi.org/10.5194/egusphere-egu21-12712, 2021.

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