Viscous Cycle: Quartz Is Key to Plate Tectonics
charles
tectonic geophysicist J. Tuzo Wilson published a paper in the journal
Nature describing how ocean basins opened and closed along North
America's eastern seaboard.
His observations, dubbed "The Wilson Tectonic Cycle," suggested the
process occurred many times during Earth's long history, most recently
causing the giant supercontinent Pangaea to split into today's seven
continents.
Wilson's ideas were central to the so-called Plate Tectonic
Revolution, the foundation of contemporary theories for processes
underlying mountain-building and earthquakes.
Since his 1967 paper, additional studies have confirmed that
large-scale deformation of continents repeatedly occurs in some
regions but not others, though the reasons why remain poorly
understood.
<more> http://www.sciencedaily.com/releases/2011/03/110316152949.htm
John Curtis
http://www.sciencedaily.com/releases/2011/03/110316152949.htm
>"It turns out that the crust beneath the plains has almost no quartz
>in it, whereas the Rockies are very quartz-rich."
>
Clay and calcite in Nebraska soil match the composition
of abyssal plains; therefore the mountain ranges crossing
the abyssal plains should be composed of basalt just like
the other midocean ridges. Quartz in the Rockies is not
an anomaly but a natural consequence of midocean-ridge
volcanoes emerging above the water line.
http://www.snopes.com/photos/natural/maiken.asp
John Curtis
George
"John Curtis" wrote in message
news:2b2517b8-48d0-40c9...@t19g2000prd.googlegroups.com...
___________________________________
Except that aren't the volcanic rocks at MORs composed primarily of
silica-poor mafic rocks?
George
John Curtis
> "John Curtis" wrote in message
>
> news:2b2517b8-48d0-40c9...@t19g2000prd.googlegroups.com...
>
> On Mar 16, 5:33 pm, charles <ckraftSPAMT...@west.net> wrote:http://www.sciencedaily.com/releases/2011/03/110316152949.htm>"It turns out that the crust beneath the plains has almost no quartz
> >in it, whereas the Rockies are very quartz-rich."
>
> Clay and calcite in Nebraska soil match the composition
> of abyssal plains; therefore the mountain ranges crossing
> the abyssal plains should be composed of basalt just like
> the other midocean ridges. Quartz in the Rockies is not
> an anomaly but a natural consequence of midocean-ridge
> John Curtis
> ___________________________________
>
> Except that aren't the volcanic rocks at MORs composed primarily of
> silica-poor mafic rocks?
>
> George
>
it grabs four molecules of water to form H4SiO4,
http://www.pmel.noaa.gov/vents/chemistry/images/vents2.gif
which latches on to iron and magnesium to become
FeMgSiO4. Each step diminishes the contribution
(percentage) of silicon to total weight of the rock.
When MOR volcano emerges above the surface,
silicon combines with atmospheric oxygen to form
SiO2, where silicon is a larger percentage in the
molecular weight of the rock. John Curtis