JOHN WELLS At the rate in which the Mississippi River is dumping mud into the Gulf of Mexico, there would be no Gulf of Mexico; it would have long been filled in, if the earth were billions of years old. JOE MEERT At the rate aluminum resides in the oceans, they are only 100 years old. We are both wrong. Your assertion is absurd. Rates change, deltas move (ever heard of a birdfoot delta). do you think that ANY scientist thinks the Mississippi is billions of years old? This is simply an absurd statement on your part. No lengthy defense needed unless you can show the publications claiming a billion year old static Mississippi River (hint: Don't waste your time searching)! HELEN Joe, do you suppose you could answer him with a little more information so people would understand why this would not be so? As a geology prof. you know that this sort of thing can be explained rather nicely, don't you? How old is the Mississippi Delta? What is a birdfoot delta, and is the Mississippi Delta one? If not, then what does that have to do with the argument? How long has the Mississippi been carting soil downstream? JOE MEERT How old is the Mississippi Delta? The Mississippi has existed in a variety of forms for at least 1 million years. The Upper Mississip was largely formed during the most recent ice age 15,000 years ago. Interestingly, the oldest river in the US is the New River! What is a birdfoot delta and is the Mississippi Delta one? A birdfoot delta is a delta shaped like a birds foot. The delta migrates as the river exploits the easiest path to the ocean. The delta changes through time and would drain into the Atchafalaya basin now and abandon New Orleans and Baton Rouge as oxbow lakes were it not for the action of the Army corps. HELEN Did it [the Mississippi River] drain someplace else before it drained into the Gulf of Mexico? How long has it been draining there? The birdfoot definition makes sense. The Nile is that way, then, right? It seems to me, as well, that as the river exploits the easiest way to the ocean it must be dumping mud to literally block itself, or it would be carving some kind of gorge, wouldn't it? So, with the rate the Army Corps of Engineers has had to work with the mouth of the Mississippi, doesn't that say something about the amount of silt and such being deposited? How long can it have been doing this? THE BARBARIAN The problem is that the practice has been to "channelize" the river, so that the delta has "birdfooted" (created a long, narrow strip of land out into the gulf) and the mouth of the Mississippi now reaches the limit of the continental shelf. This dumps into the deep, and is robbing the delta of the sediment that maintains it. The situation is now serious. New Orleans could probably not handle a major hurricane, and since most of it is not below sea level, there could be a huge disaster in the making. TOMR There's more problamatic assumptions made at the head of the thread: the Gulf of Mex is billions of years old (the formation of the Atlantic started in the Mesozoic about 150 million years ago so the gulf is certainly no older). And 2. no subsidence along the continental margin. Subsidence along the east US and Gulf is widely inferred. And 3. no longshore movement of terrigenous materials away from deltaic environments.