Large‐scale margin collapse during Messinian early sea‐level drawdown: the SW Valencia trough,NW Mediterranean

In this study, detailed mapping of the ‘Messinian markers’ and examination of their geometrical relationships in the SW Valencia trough (Western Mediterranean) have revealed the style and depositional processes associated with emersion of continental margins during the Messinian Salinity Crisis (MSC). Based on multichannel seismic profiles and well data, this article evidences the existence of two Messinian depositional units in intermediate basins (Complex Unit and Upper Unit) and four main Messinian erosional surfaces (Margin Erosion Surface, Bottom Surface, Top (Erosion) Surface and Intermediate Surface). Results show that (1) initial rapid sea‐level drawdown and exposure of the shelf and upper slope of the Valencia margin induced large‐scale destabilization of the continental slope and deposition of large detrital bodies at the base‐of‐slope in the form of major mass‐transport deposits (MTD); (2) as sea level continued to drop, the development of the Margin Erosion Surface attained full development on the margins and eroded the clastic units (MTDs) deposited during initial drawdown. At the same time, a submarine drainage network formed in the deepwater Valencia trough; (3) persistent lowstand and restrictive conditions in the area resulted in deposition of the evaporites that form the Upper Unit in the SW Valencia trough.