1. Palaeogeographic evolution of the late Miocene Rifian Corridor (Morocco):Reconstructions from surface and subsurface data
- Author
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Capella, W., Barhoun, N., Flecker, R., Hilgen, F. J., Kouwenhoven, T., Matenco, L. C., Sierro, Francisco J., Tulbure, M. A., Yousfi, Mohamed Zakaria, Krijgsman, W., Paleomagnetism, Stratigraphy and paleontology, Tectonics, Stratigraphy & paleontology, Paleomagnetism, Stratigraphy and paleontology, Tectonics, and Stratigraphy & paleontology
- Subjects
Mediterranean climate ,Late Miocene ,Rif ,010504 meteorology & atmospheric sciences ,Global climate ,Earth and Planetary Sciences(all) ,Water exchange ,Mediterranean-Atlantic exchange ,Biostratigraphy ,Messinian Salinity Crisis ,010502 geochemistry & geophysics ,01 natural sciences ,Marine gateways ,Paleontology ,General Earth and Planetary Sciences ,Palaeogeography ,Sediment transport ,Geology ,0105 earth and related environmental sciences - Abstract
The Rifian Corridor was one of the Mediterranean–Atlantic seaways that progressively restricted and caused the Messinian Salinity Crisis (MSC). Many key questions concerning the controls on the onset, progression and termination of the MSC remain unanswered mainly because the evolution of these seaways is poorly constrained. Uncertainties about the age of restriction and closure of the Rifian Corridor hamper full understanding of the hydrological exchange through the MSC gateways: required connections to sustain transport of salt into the Mediterranean for the primary-lower gypsum and halite stages. Here we present integrated surface-subsurface palaeogeographic reconstructions of the Rifian Corridor with improved age-control. Information about age and timing of the closure have been derived from high-resolution biostratigraphy, palaeoenvironmental indicators, sediment transport directions, and the analysis of published onshore subsurface (core and seismic) datasets. We applied modern taxonomic concepts to revise the biostratigraphy of the Rifian Corridor and propose astronomically-tuned, minimum-maximum ages for its successions. Finally, we summarise the palaeogeographic evolution in four time slices corresponding to the middle Tortonian (10.57–8.37), late Tortonian (8.37–7.25 Ma), early Messinian (7.25–6.35 Ma), and late Messinian (6.35–5.33 Ma). Several successions record the closure of the corridor via a continuous marine to continental-lacustrine transition. The youngest dated marine sediments represent a good approximation of the age of seaway closure. The closure of the South Rifian Corridor is constrained to 7.1–6.9 Ma; that of the North Rifian Corridor is more uncertain and ranges from 7.35 to ca. 7 Ma. We conclude that the Rifian Corridor was already closed in the early Messinian and did not contribute to the restriction events that resulted in the MSC. Because the Betic Corridor is also closed by the early Messinian, the modern Gibraltar Straits remain the sole option in the Western Mediterranean as last Messinian seaway that was open during the MSC. Our results imply that the Gibraltar Straits could have been established as the exclusive Mediterranean-Atlantic portal already in the late Miocene, and therefore we suggest that future field and drilling campaigns should target the Alboran Sea and the Gibraltar region to investigate water exchange before and during the Messinian Salinity Crisis and its impact on Atlantic circulation and global climate.
- Published
- 2018