how old are the gulf stream and the NAC?

Question

After reading about the NAC (North Atlantic Current) weakening in the news, we got to wondering about its history and that of the gulf stream. Specifically, how and when did they start? Were there conditions during the last ice age that prevented such currents forming, and we can point to a time X when the earth was warm (and the ice receeded enough) for them to do so? Or were they always there, just maybe shorter? The fact that there's worries about the NAC cutting off and europe cooling down considerably points to at least that one not being a guaranteed, always on thing.

Googling "how old is" or "age of" for these currents only returns dates for when they were discovered - and I'm fairly sure the gulf stream existed prior to 1513.

So I hope that someone here has knowledge beyond that: how did these ocean currents come to be? And roughly when in our planet's long history would that have happened?

Answer 1

This is what I found on Wiki, researching the same question: The isthmus of Panama is thought to have been formed around 3 million years ago, separating the Atlantic and Pacific Oceans and causing the creation of the Gulf Stream. This was first suggested in 1910 by North American paleontologist Henry Fairfield Osborn. He based the proposal on the fossil record of mammals in Central America. This conclusion provided a foundation for Alfred Wegener when he proposed the theory of continental drift in 1912. What now bugs me is the outline of sea/oceanic currents before the isthmus closed.