Re: evidences against subduction theory


"Timberwoof" <timberwoof.spam@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:timberwoof.spam-552BC2.16432312072007@xxxxxxxxxxxxxxxxxxxxxxxxxxx
In article <Nrxli.3175$O9.1894@xxxxxxxxxxxxxxxxxxxxxx>,
"George" <george@xxxxxxxxxxxxxxx> wrote:

"Florian" <first_name@xxxxxxxxxxxxx> wrote in message
news:1i15iu7.hx06me1i9igafN%first_name@xxxxxxxxxxxxxxxx
George <george@xxxxxxxxxxxxxxx> wrote:

Explain how GPS and deep focus seismicity help to make the
difference
between subduction and overthrusting?

--
Florian


http://images.google.com/imgres?imgurl=http://www.es.ucl.ac.uk/people/mi
lsom/ntect3.jpg&imgrefurl=http://www.es.ucl.ac.uk/people/milsom/smtrntct
.htm&h=885&w=525&sz=142&hl=en&start=18&tbnid=uNg1wi3B-WNauM:&tbnh=146&tb
nw=87&prev=/images%3Fq%3Dseismic%2Bsection%2Bof%2Bsubduction%26gbv%3D2%2
6svnum%3D10%26hl%3Den%26sa%3DG

George

Where does it tell that GPS and deep focus seismicity between
subduction and overthrusting?

In both cases there is convergence, and in both cases there is deep
focus seismicity.


--
Florian

Floppy, overthrusting nearly always causes moutain building (see the
Appalachians and the Rocky Mountains, for example). Since that is the
case, why is it that your subduction "overthrusting" is located at the
lowest elevations on the face of the earth?

How come subduction is also associated with island arcs and mountain
chains?


Subduction occurs beginning in the trenches, which are the lowest
elevations on the Earth's surface. The island arcs are formed adjacent to
the trenches from the rise of magma originating from the partial melting of
the subducting slab. The magma rises through the upper slab, causing
swelling at the surface, and eventually, characteristic subduction-related
volcanism at the surface. Mountain chains such as the Andes are thought to
form when the subducted slab suddenly detaches from the slab above it along
the line of subduction, releasing the upper slab, causing it to rise
suddenly. The Andes records many such sudden uplifts, as well as
characteristic subduction-related volcanism. We saw the same phenomenon
during the 2004 Sumatran Earthquake. Nearly the entire coastline of Western
Sumatra along the fault break uplifted as much as 150 cm(though not all of
it all at once - some of it uplifted slowly over the course of the previous
few years as the strain increased within the fault zone), exposing
previously submerged coral reefs. Secondly, overthrusting, as is seen in
the Rocky mountains, almost never reaches the mantle. It usually reaches
the crustal basement, but no further. In subduction, the lower slab always
extends well into the mantle and undergoes partial melting.

George


.

Relevant Pages

  • Re: evidences against subduction theory
    ... J. Taylor wrote: ... between subduction and overthrusting? ... where we have subduction. ... How could we measure its heterogeneity? ...
    (sci.geo.geology)
  • Re: evidences against subduction theory
    ... Your map clearly demonstrates subduction, ... overthrusting. ... Subduction zones occur within Oceanic-oceanic ... Showing trenches are different does not answer the question. ...
    (sci.geo.geology)
  • Re: evidences against subduction theory
    ... Your map clearly demonstrates subduction, ... overthrusting. ... It's a lousy map. ... Subduction zones occur within Oceanic-oceanic ...
    (sci.geo.geology)
  • Re: evidences against subduction theory
    ... between subduction and overthrusting? ... Where does it tell that GPS and deep focus seismicity between ...
    (sci.geo.geology)
  • Re: evidences against subduction theory
    ... first_name@xxxxxxxxxxxxx (Florian) wrote: ... There is no subduction but overthrusting. ... how does overthrusting happen? ... Because of the pressure in the mantle du to expansion, ...
    (sci.geo.geology)