I think the correct way to think about the THC nomenclature is that as long as there have been large scale salt and temperature gradients there has been *a* thermohaline circulation, though not necessarily the current one.
It strikes me that the large scale salinity gradients may require ice sheets, so that would put the age at only 3 million years. Before that it would mostly have been a thermal circulation. I think it's safe to say that there has been a large scale circulation ever since there was an ocean. Fluids are like that. mt On 9/26/07, Eric Swanson <[EMAIL PROTECTED]> wrote: > > As I recall, the latest round of Ice Ages began roughly 3 million > years ago. > > Wallace Broecker suggested that this had something to do with changes > in ocean circulation which resulted from the closure of the Isthmus of > Panama. His idea was that the closure isolated the North Atlantic > from the Pacific Ocean and then the transport of moisture by > atmospheric circulation over the new barrier resulted in an increase > in salt in the North Atlantic. This process would then have resulted > in the northern THC, as the density difference was eventually > balanced. > > E. S. > ------------------ > Tom Adams wrote: > > Well, I botched that one! millions not billions. > > > > The Atlantic Ocean has been around for 130 million years. > > > > Check out these tectonic plate animations for some *real* global > > change: > > > > http://www.ucmp.berkeley.edu/geology/tectonics.html > > > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/globalchange -~----------~----~----~----~------~----~------~--~---
