SURAT AR-RAHMAN
He has made the two seas to flow freely (so that) they meet together: between them is a barrier to prevent them from transgressing (Mixing).Then which of the favors of your lord will you deny.
Scientists discovered that in the places where two different seas meet, there is a barrier between them. This barrier divides the two seas so that each sea has its own temperature, salinity and density. There is a slanted unseen water barrier between the two seas.....But the Quran states this 1'400 years ago.Then which of the favours of your Lord will you deny.