EGU General Assembly 2020
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Latest Miocene Mediterranean-Atlantic gateway restriction: The Atlantic's side of the story

Zhi Lin Ng1, Francisco Javier Hernández-Molina1, Débora Duarte1,2, Francisco Javier Sierro3, Santiago Ledesma4, Estefanía Llave5, Cristina Roque6,7, and Mike Rogerson8
Zhi Lin Ng et al.
  • 1Department of Earth Sciences, Royal Holloway University of London, United Kingdom
  • 2Instituto Português do Mar e da Atmosfera (IPMA), Portugal
  • 3Departamento de Geología, Universidad de Salamanca, Spain
  • 4Naturgy Energy Group S.A., Spain
  • 5Instituto Geológico y Minero de España (IGME), Spain
  • 6Estrutura de Missão para a Extensão da Plataforma Continental (EMEPC), Portugal
  • 7Instituto Dom Luiz (IDL), Portugal
  • 8School of Environmental Sciences, University of Hull, United Kingdom

The closure of Late Miocene Mediterranean-Atlantic gateways and the restriction of Mediterranean Outflow Water (MOW) led to the Messinian Salinity Crisis (MSC), the dynamics of which is not well understood. However, restriction of the Mediterranean-Atlantic exchange and the Mediterranean Outflow Water (MOW) is one of the prerequisites to generate hypersaline conditions for evaporitic deposition. During the Late Miocene, MOW circulation was active through a Mediterranean-Atlantic exchange of the Betic, Riffian, and possibly Gibraltar gateways. This connection is thought to have ceased or reduced with the onset of the MSC, before re-establishing through the Gibraltar gateway since the Pliocene to the present. In this study, we define the sedimentary evolution of the Neogene Basins of the Gulf of Cádiz to investigate MOW evolution during the latest Miocene. Seismic interpretation shows an Upper Messinian sedimentary unit of transparent seismic facies. It could also be found in the lower Guadalquivir and Gharb basins, and towards the West Portuguese margin. Biostratigraphic dating indicate an onset of deposition predating the MSC. Distribution of this transparent unit implicates the dominant deposition of hemipelagic/pelagic deposits during a period of quiescence in the Atlantic margins, subsequent to MOW disconnection. This suggests that weakening or cut-off of the intermediate bottom currents of the Mediterranean-Atlantic exchange through the Betic-Gibraltar-Riffian paleo-gateways precedes the onset of MSC evaporites. This work is crucial for the understanding of sedimentary, paleoceanographic and climatic implications of the Latest Miocene Mediterranean isolation in the Atlantic margins.

How to cite: Ng, Z. L., Hernández-Molina, F. J., Duarte, D., Sierro, F. J., Ledesma, S., Llave, E., Roque, C., and Rogerson, M.: Latest Miocene Mediterranean-Atlantic gateway restriction: The Atlantic's side of the story, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-82,, 2020.

This abstract will not be presented.