Re: Plate tectonics - Back to the FAQS

From: don findlay (don_at_tower.net.au)
Date: 01/30/05 

Date: 30 Jan 2005 15:39:50 -0800

Bigdakine wrote:
> >Subject: Re: Plate tectonics - Back to the FAQS
> >From: "George" george@wtfiswrongwithyou.com
> >Date: 1/29/05 10:13 PM Hawaiian Standard Time
> >Message-id: <_G0Ld.26525$ox3.3773@attbi_s04>
> >
> >
> >"Landy" <none@nowhere.com> wrote in message
> >news:cth03k$22m$1@seagoon.newcastle.edu.au...
> >>
> >> "don findlay" <don@tower.net.au> wrote in message
> >> news:1107012674.823933.211810@z14g2000cwz.googlegroups.com...
> >>> Q1. Call it 'expanded' or 'growth' or whatever, ...what is the
> >>> fundamental, last word, bottom line evidence that the Earth has
got
> >>> bigger?
> >>>
> >>> A1. The creation of the ocean floors. These amount to two
thirds of
> >>> the Earth's surface at the present time, and give us an
indication of
> >>> the order of magnitude of enlargement of the Earth. The abyssal
hills,
> >>> which provide the record of ocean floor growth are the most
prolific
> >>> (and least mentioned - within plate tectonics) structures of the
ocean
> >>> floors.
> >>
> >> I just can't help myself.....
> >> So then why, Don, is there no ocean floor older than Jurassic? I
could say
> >> that you're forgetting (conveniently) that ocean floor is
destroyed at the
> >> same
> >> rate it is created. But that would be like trying to argue
evolution with
> >a
> >> creationist.
> >>
> >> So what's the answer Don? To deny that seafloor is destroyed by
subduction
> >> is to argue that there was no seafloor prior to the Jurassic and
hence the
> >> earth
> >> had no oceans. In fact if you're arguing that the current area of
oceans
> >> represent
> >> earth expansion since the Jurassic, the you're arguing by default
that
> >prior
> >> to then
> >> the earth was entirely continental crust.
> >> cheers
> >> Bill
> >>
> >
> >Actually, Bill. There is, in point of fact, plenty of ocean floor
that is
> >older
> >than Juassic. The thing that people keep forgetting is that a lot
of the
> >older
> >ocean floor is no longer beneath the sea, but is now welded to the
> >continents,
> >or buried beneath them. I've got about 100 lbs of former ocean
floor in my
> >shed
> >that ranges from 350 million to 1 billion years old.
>
> I have a few chunks of the Fransican formation in my parent's flower
bed.
> Others in use as paper weights.
>
> Oh, what an ignominious end for such old rocks.
>
>
>
> I've got a boulder of
> >Devonian-aged ocean floor in my yard that is about 1,000 lbs. But I
> >understand
> >your point. The EEers keep whining that there are more spreading
ridges than
> >
> >there are subduction zones, but fail to recognize that the
subduction zones
> >are
> >subducting at a rate that is at least 5 to 6 times faster, on
average, than
> >the
> >spreading ridges are spreading. The Indian plate is subducting at
the
> >location
> >of the Sumatra trench at a rate of about 60 cm/yr, while the East
Pacific
>
> Whoops, I know thats wrong. Its 6cm/yr. However, in the Northern
Tonga area
> subdcution rates exceed 20cm/yr.

That's the stuff Stu. Set him right. (Redfaced George, ..and here we
are thinking it's on account of the coal.) 61mm say the UGS hulklinks
and at the same time the plate is barrelling southeasterly towards the
convergent boundary with Australian Plate.
<http://users.indigo.net.au/don/ng/hulk.html>
Got an explanation for that one, Stu? Other than an expanding plate, I
mean.

Come on, Seismo.

> >rise
> >spreads at a rate of about 11 cm/yr.
>
> Which is abnormally fast. Average sea-floor spreading rate is
~3-4cm/yr while
> average suduction rate is several times that.
>
> Stuart
> >
> >
> >
> >
> >
> >
> >
> >
>
>
> Dr. Stuart A. Weinstein
> Ewa Beach Institute of Tectonics
> "To err is human, but to really foul things up requires a
creationist"
>
>
> "Creationists aren't impervious to Logic: They're oblivious to it."

Relevant Pages

  • Re: Earth expansion - puzzled......
    ... If it is only for a period of time, how does that fit into Plate ... You can't have spreading ridges without transforms anymore ... >>than you can have subduction zones without transforms. ... I've given you the facts. ...
    (sci.geo.geology)
  • Re: Yellowstone geology
    ... and the densest plate will slide beneath the lighter density plate. ... What I'm wondering about is the subduction angle. ... angle once it slips under lighter continental crust. ... In thinking about the spreading center from which the Farallon and ...
    (sci.geo.geology)
  • Re: Really interesting paleogeographic map suggests ocean basins opening and closing repeatedly in t
    ... And the evidence for the farallon plate is completely known from PThttp://en.wikipedia.org/wiki/Farallon_Plate ... And the supposed spreading by EPR into the Western Pacific 4548 miles ... subduction at all, over the top of another plate that was subducting ...
    (sci.geo.geology)
  • Re: Dons blog
    ... > mechanically no difference between subduction and overriding, ... >> has to accept a considerable override, but no movement and no growth. ... > crust and the mantle] exploit the anisotropies available to them. ... >> The growth of the Cocos plate should, I suppose, show the extensional ...
    (sci.geo.geology)
  • Re: Kook warning, Oriel36
    ... >> study of the Earth evolution with the conditions of stars and galaxies ... > say in the next sentence below about subduction. ... >> subduction as a simple push of one plate down another, ... I don't know whether it's mass creation - ...
    (sci.geo.geology)