The Mississippi's Curious Origins

Scientific American ^ | January 2007 issue | Roy B. Van Arsdale and Randel T. Cox

[SunkenCiv]

A mountain range once separated the continental interior of the U.S. from the Gulf of Mexico. Some clever geologic sleuthing has revealed how that barrier was breached, allowing the river to reach the Gulf... [S]omehow the once continuous Ouachita-Appalachian range was cleaved in two, leaving room for the Mississippi River to flow into the Gulf of Mexico. The explanation for the split, which the two of us have been investigating for most of the past decade, touches on many other mysteries of North American geology, too -- such as why you can find diamonds in Arkansas and why the largest earthquake that was ever recorded in the contiguous U.S. occurred not in California or Washington but in Missouri, of all places...

[colorado tanker]

Well, there does appear to be a submerged ridge under the Yucatan Channel and Florida Straits.

http://images.google.com/imgres?imgurl=http://walrus.wr.usgs.gov/infobank/gazette/jpg/regions/fr_gm.jpg&imgrefurl=http://walrus.wr.usgs.gov/infobank/gazette/html/regions/gm.html&h=1832&w=2375&sz=1184&hl=en&start=9&tbnid=HcfnE04UTSP64M:&tbnh=116&tbnw=150&prev=/images%3Fq%3D%2Bsite:walrus.wr.usgs.gov%2Bgulf%2Bof%2Bmexico%2Bmap%26ndsp%3D20%26svnum%3D10%26hl%3Den%26lr%3D%26safe%3Doff%26rls%3DGGLG,GGLG:2005-45,GGLG:en

[Ben Ficklin]

Wiki's statement that the remaining Ouachitas in AR and OK are remnents of the original mountains is not exactly accurate.

The quartz deposits that Wiki mentions is what has preserved what's left of the Ouachitas. Each mountain/hill has a horizonal bed of quartz located towards the top that is exposed around the entire perimeter, protecting the mountain/hill from erosion.

The original mountains that did not recieve the mineralized water and resulting quartz bed are long gone.

The Ouachita Natl Forest website has a good explanation of the geology.

[blam]

This is a map of the world's oceans with the water level lowered by about 330 feet. Some say the water level was lowered by 500 feet during the Ice Age.

[colorado tanker]

Looks like it would have to get closer to the 500 feet mark to close off the Gulf of Mexico, but I wouldn't at all be surprised if you're right, that it became a freshwater lake.

I notice on the map that Sundaland appears and the English Channel disappears. I understand some modern tankers barely clear the Channel bottom - it's pretty shallow. The Baltic also disappears, where there's some interesting archeology starting up. Japan also joins the mainland - making for some intriguing possibilities as to its ethnic history.

[blam]

Notice the Mediterranean was probably blocked (and the dessicated), the Red Sea probably evaporated away and the Persian Gulf is missing too.

[colorado tanker]

The dam between the Med and the Black Sea (Lake?) is really thick, too.

[Bernard Marx]

I can't speak to the whole issue but the snippet mentions the Missouri earthquakes and diamonds in Arkansas. I know there are plenty of volcanic/contact metamorphic indications in western North Carolina too.

All those indicate substantial tectonic activity: plate movement and some event that allowed plutonic rocks in the form of diatremes (Arkansas) and pegmatite dikes (N.C.) to surge upward from very deep levels. Sounds to me like there was lots of rockin' and rollin' in that area long before Elvis's time.

[colorado tanker]

North America, South America and Africa all mixing it up must have made for exciting times!

[Sawdring]

Cross the mighty Mississippi at its source in Minnesota.

[Chani]

That graphic was awesome...thanx!

[ruoflaw]

Are ya sure it wasn't the Quakers or the Shakers?

[RightWhale]

They might have thought so at the time. :)

[ruoflaw]

LOL I hope none of us ever see that happen again!

[RightWhale]

A few years ago there were several threads about the quakes; historical accounts from some who were there. If they got another quake series like that now the destruction would be beyond description. So let's hope because there isn't much else to do about it.

[ruoflaw]

I remember reading some of those accounts.

[Condor51]

Weird map?? It shows all the Great Lakes gone.

Yet the deepest part of Lake Michigan is 923ft and Superior is 1,333 ft - so I don't 'get' the 330 ft lower water level making them disappear??

[blam]

"Weird map?? It shows all the Great Lakes gone. "

The Great Lakes were covered by ice that was 1-2 miles thick during the Ice Age. I believe it was the movement of these glaciers that 'carved-out' the Great Lakes.

[Condor51]

****The Great Lakes were covered by ice that was 1-2 miles thick during the Ice Age. I believe it was the movement of these glaciers that 'carved-out' the Great Lakes.****

Yeah, I know that. Growing up in Chicago that point was drilled into our little heads almost daily that our surrounding Geography was carved out by Glaciers (Hills, Moraine Valley, Boulders in Chicago that 'shouldn't be there', etc).

But I was referring specially to the map that shows the Great Lakes disappearing if the sea level dropped 330 ft. That doesn't make sense.

[blam]

"But I was referring specially to the map that shows the Great Lakes disappearing if the sea level dropped 330 ft. That doesn't make sense.

They weren't there...makes sense to me.

[SunkenCiv]

That old topic linked in #11 is a dead link, here’s the original:

Dangerous Echoes Of Ice Ages Past
by Louisa Dalton
Stanford - March 7, 2001
TERRADAILY
http://www.spacedaily.com/news/earthquake-01b.html

and the other topic linked there is still good, so here’s an interesting, related new one:

Upsurge in big earthquakes predicted for 2018 as Earth rotation slows
The Guardian | 18 November 2017 | Robin McKie
Posted on 11/21/2017 3:31:51 AM PST by TigerLikesRooster
http://www.freerepublic.com/focus/chat/3606717/posts
7 posted on 11/21/2017 3:49:01 AM PST by Lonesome in Massachussets (Psephomancers for Hillary!)
http://www.freerepublic.com/focus/chat/3606717/posts?page=7#7