Topography of the Red Sea Miocene evaporites

What is it about?

Evaporites were deposited in the Red Sea up until the end of the Miocene. Their present surface topography represents the effects of early deformation that is now obscured by later movements and overlying sediments in older marginal evaporite (salt) deposits, such as off Brazil and Angola. Knowing in general how these deposits evolve at early stages may help prediction of petroleum-relevant strata in the older deposits. The Red Sea evaporite surface mapped out using a variety of shallow seismic reflection data was shown to record primarily the effects of evaporite flowage, itself linked to the morphology of the spreading centre running along the Red Sea axis.

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Photo by Samuel Scrimshaw on Unsplash

Photo by Samuel Scrimshaw on Unsplash

Why is it important?

The results show that the evaporite surface is depressed in areas where the deposits have flowed towards the spreading centres, confirming the mapping of flowage structures with multibeam sonar (Augustin et al.). At a more regional scale, the evaporite surface was found to rise towards the south, in the opposite direction to the flow of the sea water that supplied the evaporites, according to some paleontological evidence. We argued this also implied a regional depression of the evaporites in the central Red Sea, caused by more extensive flowage there. These results prompt the question of whether similar structures may have existed in the South Atlantic during its earlier stages of opening, in particular, in areas now hosting petroleum reserves off Brazil and Angola.