[Rockhounds] New Madrid fault / Rivers

[Alan Goldstein]

The failed rift dates to the Precambrian - about 700 million years ago.

An article on the history of the earth's crust and rivers is in the current 
issue of Earth. Dr. Paul Potter (emeritus professor at University of 
Cincinnati) found - a long time ago - that a number of the worlds major 
rivers are associated with failed rifts. The Nile, Niger, Amazon and 
Mississippi are among them. Until the Andes rose, the Amazon drained into 
the Pacific.

Rivers on the early supercontinents were so large they made the Amazon River 
look like a creek! Rivers became smaller as plants began to stablize the 
earth's surface.

Alan

----- Original Message ----- 
From: "Mr EMan" <mstreman53 at yahoo.com>
To: "Rockhounds at drizzle.com: A mailing list for rock and gem collectors" 
<rockhounds at lists.drizzle.com>
Sent: Tuesday, March 24, 2009 11:29 PM
Subject: Re: [Rockhounds] New Madrid fault


>
> Coming late to the well posted thread... Historically an absence of 
> movement was an indicator of an overdue rupture not an exhaustion of 
> potential. I guess the short answer in this research concludes that the 
> stretched zone from the NMFzone is now in equilibrium.
>
> As to the original question, traces of the fault are at ground level but 
> the bedrock is covered by river and glacial sediments.  I don't recall 
> what the oldest sand blowout to be dated, but I do know that several have 
> been excavated from the 1811 quake and there are some older ones.
>
> The failed rift of the New Madrid was believed started sometime after the 
> Triassic(190mya) and I've been told by a researcher that there was 
> evidence of a mantle plume forming there. Unlike Hawaii it was mid-sized 
> and traveled under the eastern US(technically the NA Plate moved westward) 
> and the remnant of that mantle plume is the Bermudas.  For what it is 
> worth.
>
> Eman
>
>
> --- On Sat, 3/21/09, J Bryan Kramer <codeburner at gmail.com> wrote:
>
>> I thought some may be interested in this:
>>
>> <http://www.sciencedaily.com/releases/2009/03/090313145956.htm>
>
>> Do deep subsurface faults always produce measurable surface
>> movement?
>
> -- 
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