PDA

View Full Version : Great Eliptical Basin micro-quakes



dgavin
2011-Dec-15, 08:11 PM
This thread is not to imply anything unusual at all, it's just not often you actualy see tiny quakes all around the great eliptical basin edge, sort of in a way outling the entire basin:

Like in this attached image from today:

15970

Image re-used according to USGS/ANSS/World Seismology Data Center's public image usage clauses, and is not copyright protected.

CJSF
2011-Dec-15, 08:37 PM
dgavin,

Do you have any good internet links to resources about this "Great Elliptical Basin?" I hadn't heard the term until you posted it, and there seems to be very few lay-person's level pages coming up with a Google search.

Thanks,
CJSF

Squink
2011-Dec-15, 10:46 PM
Nice maps here: The Great ellipse (http://www.mantleplumes.org/CRBEllipse.html)

dgavin
2011-Dec-16, 01:06 AM
Nice maps here: The Great ellipse (http://www.mantleplumes.org/CRBEllipse.html)

Thats the best one, thansk Squink. Yellowstone-Newberry Hotspot for some additionl info.

dgavin
2011-Dec-16, 01:34 AM
Here is an indepth read on the hotspot http://www.geosociety.org/pubs/gsatoday/archive/sci0012.htm

And some intresting information on the flood bassalts http://volcano.oregonstate.edu/book/export/html/486

CJSF
2011-Dec-16, 07:07 AM
ok.. I was hoping for a description even less technical than that . . . (blushing)

CJSF

dgavin
2011-Dec-16, 07:36 PM
Less Technical... I'll try...

Ok the Basin itself while it looks like a formation typically formed by either an impact event, or a large scale volcanic caldera, was actually formed by opposing movements of the Continental crust.

In simplest terms, the continental crust at the north side of the basin is moving inland, the crust at the south side is moving out to sea. This causes the crust and upper mantle of the region between these two area's to twist in a semi-circular fashion.

In the most basic sense, it's a slow moving maelstrom (whirlpool) thats made out of rock itself.

The Yellowstone/Newberry/Long-valley Hot-spot region in this basin is now thought to be caused by this twisting of the crust in the upper mantle, instead of a plume from the lower mantle or the Earth's core.

As this hot-spot was discovered to have no lower mantle source via seismic imaging techniques, the Great Elliptical Basin took on more significance in recent decades, as it turns out it wasn't the caldera of the hot-spot that broke surface 17mil years ago, it's much much older then that. So it appears to be direct evidence for new type of upper mantle hot-spot volcanism, and that the basin formation was the cause, and not the effect of the hot-spot.

*edit to add*

Far as I know this would make it a unique spot on the planet as it's the only known formation of a rock based whirlpool like region. It's earth's equivlent of Jupiters Red Spot, but it's made out of rock instead of Gas.

PraedSt
2011-Dec-16, 08:12 PM
I hadn't heard about this either. I'm taking a course on basic geology and I can use this in the exam. Thank you! :)

CJSF
2011-Dec-17, 12:17 AM
That's a great basic summary! Thank you!

CJSF

dgavin
2011-Dec-17, 01:18 AM
My comment about it being Earth's equivlent of Jupiters Red Spot was sort of off handed.

But after looking at Google Earth and noticed a few things rather intresting, in a vulcan eye brow raising sort of way.

1. This feature is large enough to be seen from space.
2. And porpotionaly, it's about the same relative size as Jupiters red spot.

Maybe there is more to my off handed comment then I thought.

PraedSt
2011-Dec-17, 08:19 PM
Much as I want to, I don't think I should mention monoliths in my exam. :D

dgavin
2011-Dec-18, 04:39 AM
Much as I want to, I don't think I should mention monoliths in my exam. :D

:rofl:

Swift
2012-Aug-05, 08:54 PM
Moved from Science & Technology