EGU21-4185
https://doi.org/10.5194/egusphere-egu21-4185
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Transition from continental rifting to oceanic spreading in the northern Red Sea area

Sami El Khrepy1,2, Ivan Koulakov3,4,5, Nassir Al-Arifi1, Mamdouh S. Alajmi6, and Ayman N. Qadrouh6
Sami El Khrepy et al.
  • 1King Saud University, Saudi Arabia (k_sami11@yahoo.com) & (nalarifi@ksu.edu.sa)
  • 2National Research Institute of Astronomy and Geophysics, Seismology Department, NRIAG, Helwan 11421, Egypt (k_sami11@yahoo.com)
  • 3Novosibirsk State University, Novosibirsk, Russia, Pirogova 2, Novosibirsk 630090, Russia (ivan.science@gmail.com)
  • 4Novosibirsk State University, Novosibirsk, Russia, Pirogova 2, Novosibirsk 630090, Russia (ivan.science@gmail.com)
  • 5Institute of Volcanology and Seismology FEB RAS, Piip Boulevard, 9, 693006, Petropavlovsk-Kamchatsky, Russia (ivan.science@gmail.com)
  • 6King Abdulaziz City of Science and Technology, Riyadh, Saudi Arabia (malajmi@kacst.edu.sa, aqadrouh@kacst.edu.sa).

Lithosphere extension, which plays an essential role in plate tectonics, occurs both in continents (as rift systems) and oceans (spreading along mid-oceanic ridges). The northern Red Sea area is a unique natural geodynamic laboratory, where the ongoing transition from continental rifting to oceanic spreading can be observed. Here, we analyze travel time data from a merged catalogue provided by the Egyptian and Saudi Arabian seismic networks to build a three-dimensional model of seismic velocities in the crust and uppermost mantle beneath the northern Red Sea and surroundings. The derived structures clearly reveal a high-velocity anomaly coinciding with the Red Sea basin and a narrow low-velocity anomaly centered along the rift axis. We interpret these structures as a transition of lithospheric extension from continental rifting to oceanic spreading. The transitional lithosphere is manifested by a dominantly positive seismic anomaly indicating the presence of a 50–70-km-thick and 200–300-km-wide cold lithosphere. Along the forming oceanic ridge axis, an elongated low-velocity anomaly marks a narrow localized nascent spreading zone that disrupts the transitional lithosphere. Along the eastern margins of the Red Sea, the lithosphere is disturbed by the lower-velocity anomalies coinciding with areas of basaltic magmatism.

How to cite: El Khrepy, S., Koulakov, I., Al-Arifi, N., S. Alajmi, M., and N. Qadrouh, A.: Transition from continental rifting to oceanic spreading in the northern Red Sea area, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4185, https://doi.org/10.5194/egusphere-egu21-4185, 2021.

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