While our tiny land mass remained locked into Pangea we entered a desert latitude once more as we continued our journey beyond the equator.

This would have been roughly 290 million years ago.

However, sea water would occasionally encroach the land via rifts.

The result was that salt was deposited on our land during periodic marine advances.

And that is precisely what happened here at Carrickfergus, on the north shore of Belfast Lough; the ocean extended in and onto the land.

Once in, it became isolated from the rest of the ocean, and eventually evaporated under the hot desert sun.

As the water evaporated, layers of rock salt were left behind which - as the clip shows - would eventually be mined here at Kilroot.

In Northern Ireland deposits of salt were formed during both the Permian and Triassic periods, with the Carrickfergus salt forming during the Triassic.

Salt seams have been discovered along the Antrim coast over the past century and more, with one at Larne measuring over 400 metres thick.