FWIW, Drake's Passage has always looked to me like slippage of the Antarctic and South American plates westward past a "hard" or stationary spot in the ocean crust; or vice versa; or a combination of both. Same with the Caribbean which has a similar appearance. Like northern S.A. might have been "twisted" to the southeast away from N.A. I'm sure absence of a continental shelf at the eastern tip of S.A. might tell us something; I just don't know what it might be. N.A., for whatever reasons, appears to have retained most or all of its southern and eastern continental shelf.
Anywho, I'm all but convinced our planet went through some significant trauma during historical times and the few that lived to tell about it have been written off as nut cases or cranks by the scientific community™. Odd thing, most of the myths/legends/lore tell the same or similar tale.
My pleasure.
Here’s the PDF file the author has online (was there yesterday):
http://www.sciencepub.net/report/report0202/01_1282_Impact_pub_report0202_1_2.pdf
The Eltanin impact (somewhat more than 2 million years ago, and not nearly long enough ago for his scenario) evidence was found during the Int’l Geophysical Year (which actually started in the 1950s and continued into the 1960s, iow, it lasted much longer than a year) by (no surprise here) the research vessel Eltanin. Some research has been done subsequent to that, including the finding of a layer of iridium from the impact.
Another FR topic which will probably be of interest:
http://www.freerepublic.com/focus/chat/1390424/posts