Giant Magma Blobs Ripple Earth's Surface

LiveScience.com ^ | 6/29/10

[NormsRevenge]

Hot blobs of magma - the searing liquid rock beneath the Earth's crust - can spread slow-moving ripples that soar hundreds of meters high across the Earth's surface, a new study suggests.

This phenomenon, which works on geologic time scales, may explain relatively rapid pre-historical changes in sea level that occurred without the typical waxing and waning of the polar ice sheets, which hold and release water on scales of thousands and millions of years. This unexplained sea level rise is one of geology's oldest mysteries.

During the Paleogene era (65 million to 23 million years ago), the land under Scotland moved up and down like a geological yo-yo. The surface rippled up to 1,640 feet (500 meters) over the course of only a million years - a relatively short time span, geologically-speaking.

"It appears to be caused by something deep within the Earth, moving sideways - almost like rats running underneath a carpet," said study author Bryan Lovell of the University of Cambridge.

...

A magma hot spot beneath Iceland, known as the Iceland plume, which is responsible for the European island's volcanic activity, could be behind this movement.

Data from oil exploration near the Iceland magma plume has revealed that a blob in the Earth's flowing mantle caused a pulse beneath the North Atlantic about 55 million years ago. This pulse raised and lowered the land surface and the sea floor in a rippling effect

Although scientists were confident that hot blobs exist in the mantle, evidence for the ripples at the Earth's surface have been hard to spot. While the Scotland uplift is the only example of the hot blob effect, Lovell said the movement is a natural effect of mantle convection, so there's no reason to think it isn't happening all the time, even now.

[SunkenCiv]

Thanks NormsRevenge.

http://www.sciencedaily.com/releases/2006/05/060511083341.htm
http://www.freerepublic.com/focus/chat/2328160/posts
http://www.sciencedaily.com/releases/2009/08/090819153342.htm

[ForGod'sSake]

Hey Civ; seems there was an article/thread posted last year wherein someone theorized that large chunks of subducted crust, or maybe even chunks of mantle 'more solid than yer average blob of mantle' were prone to being thrust upward and thereby, in very short order, create mountains or mountain ranges. Time frames on the order of days or weeks instead of centuries or millennia. I found it interesting since I'm not automatically inclined to accept the uniformitarianism/gradualism theories at face value any way.

When you get a free minute or two, might you be able to run it down?

[SunkenCiv]

That sounds vaguely familiar, check the keyword:

http://www.freerepublic.com/focus/keyword?k=catastrophism