The demise of a ‘salt giant’ driven by uplift and thermal dissolution

Abstract The development of giant salt basins and eventual cessation of rapid salt deposition is founded on a delicate balance of salinity and heat fluxes within the water body governed by tectonic, climatic and eustatic change. The onset of salt deposition in such basins is widely accepted to be initiated by basin restriction. However, the processes that lead to the termination of salt deposition are comparatively unclear. Here we use an array of 2D and 3D seismic surveys to reveal that the truncation surface at the top of a thick salt sequence in the Eastern Mediterranean is far more extensive than previously thought. We show that uplift of the salt driven by deformation and thermal dissolution initiated the demise of the ‘salt giant’, even prior to the final dilution and emplacement of brackish Lago Mare and fluvial deposits. Progressive uplift of the salt through the thermocline and into the under-saturated epilimnion led to dissolution. We argue that dissolved salt was recycled and re-precipitation from the hypolimnion in the deepest sections of the basin contemporaneous with dissolution of halite from the shallower epilimnion. These findings explain how rapid basinwide salt deposition was brought to an end in the Eastern Mediterranean and present a novel process for sculpting the final architecture of a ‘salt giant’.