Abstract
The Messinian Salinity Crisis (MSC) resulted from a significant multi-phase drop and subsequent reflooding of the Mediterranean Sea from 5.96 to 5.33 Ma. Well-developed drainage networks, characterized by step-like profiles and abrasion platforms, are associated to this event. The Ebro Continental Margin (Western Mediterranean) presents an additional complexity since the capture of the drainage of the adjacent subaerial Ebro Basin took place sometime prior to the Messinian stage. Using 3D seismic reflection data, this work provides new insights into the origin of the step-like profile of the Messinian erosional surface (MES) and timing of the capture of the subaerial Ebro Basin. The results obtained indicate a sedimentary-active continental slope and delta progradation during Middle-Late Miocene, in a normal regressive context associated to a pre-Messinian proto-Ebro River. The mature development attained by the Messinian Ebro River network during the MSC corroborates that the capture of the Ebro Basin occurred prior to the MSC. The configuration of the clinoforms below the MES suggests that deltaic sediments of the Messinian Paleo-Ebro River deposited during the Tortonian and initial Messinian sea-level drawdown. The MES formed at the top of the Tortonian Highstand, where a fluvial network was deeply carved, and in the topset region of the Messinian Falling Stage Systems Tract, where minor erosion occurred. Fluvial deposits are outstandingly preserved on the main valleys of the MES. Therefore, the step-like profile of the MES was not created during Zanclean inundation, but during the latest stages of the main Messinian sea-level fall and lowstand.
Highlights
In a relatively short time span (5.96 to 5.33 Ma), partial desiccation of the basin and consequent subaerial exposure of the continental margins resulted in widespread erosion of continental shelves and slopes and regressive erosion along major fluvial valleys
Using 3D seismic reflection data from the Ebro Margin (Western Mediterranean), we provide new insights into the origin of the Messinian Erosional Surface (MES) and timing of the capture of the subaerial Ebro Basin
The observed sedimentary architecture of the Ebro Continental Margin indicates a sedimentary-active continental slope and delta progradation during MiddleLate Miocene, in a normal regressive context associated to a pre-Messinian proto-Ebro River
Summary
Late Miocene sedimentary architecture of the Ebro Continental Margin (Western Mediterranean): Implications to the Messinian Salinity Crisis Cameselle (1), Roger Urgeles (1), Ben De Mol (2,3), and Angelo Camerlenghi (4) (1) Dept. Geociències Marines, Institut de Ciències del Mar (CSIC), Barcelona, Spain (acameselle@icm.csic.es), (2) Barcelona-CSI, Institut de Ciències del Mar (CSIC), Barcelona, Spain, (3) Senergy AS, Oslo, Norway, (4) Instituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Trieste, Italy
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