New Cross-Section Reveals What's Beneath North America
Posted by JAC on 6/6/2011, 6:52 am




http://www.ouramazingplanet.com/north-american-continent-cross-section-1592/


ftp://rock.geosociety.org/pub/GSAToday/1106insert-hammer/G95A_Hammer_Insert_HighRes.pdf


To see the big picture of North America, look no further than a new detailed cross-section of the continent that ventures down to its deepest roots and has uncovered a mystery at its very foundation.


The cross-section reveals how the mantle roots of the continent and the overlying continental crust both bear more than 3 billion years of scars of ancient continental collisions and eons of oceanic plates and islands getting shoved against and pushed under older continental blocks. Each layer of older crust visibly forms the basement of the next younger layer, illuminating the assembly of the North American continent at an unprecedented scale.

"This is the first time anyone's put together a cross-section of a continent with this much detail," saidRonald Clowes, a seismologist at the University of British Columbia in Vancouver and director of Lithoprobe. Even at the very base of the crust - the furthest part of the cross-section from the surface, and thus the most difficult to image - the resolution of imagery "is on the order of a couple hundred meters vertically and a few kilometers laterally, and is even better at shallower depths," he said.
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Something Strange With Volcano Eruption in Chile. Huge Gash in Earth has Formed. - JAC, 6/6/2011, 5:53 am
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