Live Science short video, a bit under 2 minutes

https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe

The gist of it is a hypothesis [1] that Greenland passed over a hotspot
between 80 and 40 million years ago, and after it emerged, Iceland was built
above the hotspot, where it stands today.

[1] not identified as such, but treated as a discovery.

Title: Iceland Comes From Greenland?

Scientists learn to better understand the movement of Greenland, as it was slowly pushed over the hotspot that is now located under neighboring Iceland.
Nothing stands still over geologic time, and even the biggest land masses are constantly being reshaped by Earth.
Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson Beck, Ernie Wrigh

[end of blurb for the video]

A really neat feature is that, while pausing the video, you can
move along the track of the video at your own pace,
and watch the conjectured path that Greenland took during those forty million years.

The hotspot seems to trace a path from the north end of Greenland to almost its south end.

Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
University of South Carolina
https://people.math.sc.edu/nyikos

On 12/19/23 2:52 PM, Peter Nyikos wrote:
> Live Science short video, a bit under 2 minutes
>
> https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
>
> The gist of it is a hypothesis [1] that Greenland passed over a hotspot
> between 80 and 40 million years ago, and after it emerged, Iceland was built
> above the hotspot, where it stands today.
>
> [1] not identified as such, but treated as a discovery.
>
> Title: Iceland Comes From Greenland?
>
> Scientists learn to better understand the movement of Greenland, as it was slowly pushed over the hotspot that is now located under neighboring Iceland.
> Nothing stands still over geologic time, and even the biggest land masses are constantly being reshaped by Earth.
> Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson Beck, Ernie Wrigh
>
> [end of blurb for the video]
>
> A really neat feature is that, while pausing the video, you can
> move along the track of the video at your own pace,
> and watch the conjectured path that Greenland took during those forty million years.
>
> The hotspot seems to trace a path from the north end of Greenland to almost its south end.

Well, you mean that Greenland seems to trace a path over the hot spot.
It seems as if the mid-Atlantic ridge also must move a bit west in this
scenario, so that Greenland's movement is a combination of its spreading
from the ridge and motion of the ridge. I wonder if Iceland and the
ridge will eventually move off the hot spot, leaving it to sink while
the hot spot gives rise to an island chain resembling Hawaii.

On 12/19/23 15:15, John Harshman wrote:
> On 12/19/23 2:52 PM, Peter Nyikos wrote:
>> Live Science short video, a bit under 2 minutes
>>
>> https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
>>
>> The gist of it is a hypothesis [1] that Greenland passed over a hotspot
>> between 80 and 40 million years ago, and after it emerged, Iceland was
>> built
>> above the hotspot, where it stands today.
>>
>> [1] not identified as such, but treated as a discovery.
>>
>> Title: Iceland Comes From Greenland?
>>
>> Scientists learn to better understand the movement of Greenland, as it
>> was slowly pushed over the hotspot that is now located under
>> neighboring Iceland.
>> Nothing stands still over geologic time, and even the biggest land
>> masses are constantly being reshaped by Earth.
>> Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson Beck,
>> Ernie Wrigh
>>
>> [end of blurb for the video]
>>
>> A really neat feature is that, while pausing the video, you can
>> move along the track of the video at your own pace,
>> and watch the conjectured path that Greenland took during those forty
>> million years.
>>
>> The hotspot seems to trace a path from the north end of Greenland to
>> almost its south end.
>
> Well, you mean that Greenland seems to trace a path over the hot spot.
> It seems as if the mid-Atlantic ridge also must move a bit west in this
> scenario, so that Greenland's movement is a combination of its spreading
> from the ridge and motion of the ridge. I wonder if Iceland and the
> ridge will eventually move off the hot spot, leaving it to sink while
> the hot spot gives rise to an island chain resembling Hawaii.

Well you know, what is the motive force that drives plate
tectonics?

Probably it would involve something on the order of heat
convection from the Earth's core.

Does the term 'mantle plume' refer to any exact model?
If it is unclear exactly what that means then the response
ends up 'we don't know'.

Is Iceland the center of the motive force opening up the
north Atlantic and Arctic oceans? Maybe?

On 12/20/23 6:54 AM, Trolidan7 wrote:
> On 12/19/23 15:15, John Harshman wrote:
>> On 12/19/23 2:52 PM, Peter Nyikos wrote:
>>> Live Science short video, a bit under 2 minutes
>>>
>>> https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
>>>
>>> The gist of it is a hypothesis [1] that Greenland passed over a hotspot
>>> between 80 and 40 million years ago, and after it emerged, Iceland
>>> was built
>>> above the hotspot, where it stands today.
>>>
>>> [1] not identified as such, but treated as a discovery.
>>>
>>> Title: Iceland Comes From Greenland?
>>>
>>> Scientists learn to better understand the movement of Greenland, as
>>> it was slowly pushed over the hotspot that is now located under
>>> neighboring Iceland.
>>> Nothing stands still over geologic time, and even the biggest land
>>> masses are constantly being reshaped by Earth.
>>> Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson
>>> Beck, Ernie Wrigh
>>>
>>> [end of blurb for the video]
>>>
>>> A really neat feature is that, while pausing the video, you can
>>> move along the track of the video at your own pace,
>>> and watch the conjectured path that Greenland took during those forty
>>> million years.
>>>
>>> The hotspot seems to trace a path from the north end of Greenland to
>>> almost its south end.
>>
>> Well, you mean that Greenland seems to trace a path over the hot spot.
>> It seems as if the mid-Atlantic ridge also must move a bit west in
>> this scenario, so that Greenland's movement is a combination of its
>> spreading from the ridge and motion of the ridge. I wonder if Iceland
>> and the ridge will eventually move off the hot spot, leaving it to
>> sink while the hot spot gives rise to an island chain resembling Hawaii.
>
> Well you know, what is the motive force that drives plate
> tectonics?

Mantle convection and slab pull, as I understand it.

> Probably it would involve something on the order of heat
> convection from the Earth's core.
>
> Does the term 'mantle plume' refer to any exact model?
> If it is unclear exactly what that means then the response
> ends up 'we don't know'.
>
> Is Iceland the center of the motive force opening up the
> north Atlantic and Arctic oceans?  Maybe?

It's at least situated right on the mid-Atlantic ridge. Whether that's
the center of the motive force is open to discussion. Why?

On 12/20/23 08:01, John Harshman wrote:
> On 12/20/23 6:54 AM, Trolidan7 wrote:
>> On 12/19/23 15:15, John Harshman wrote:
>>> On 12/19/23 2:52 PM, Peter Nyikos wrote:
>>>> Live Science short video, a bit under 2 minutes
>>>>
>>>> https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
>>>>
>>>> The gist of it is a hypothesis [1] that Greenland passed over a hotspot
>>>> between 80 and 40 million years ago, and after it emerged, Iceland
>>>> was built
>>>> above the hotspot, where it stands today.
>>>>
>>>> [1] not identified as such, but treated as a discovery.
>>>>
>>>> Title: Iceland Comes From Greenland?
>>>>
>>>> Scientists learn to better understand the movement of Greenland, as
>>>> it was slowly pushed over the hotspot that is now located under
>>>> neighboring Iceland.
>>>> Nothing stands still over geologic time, and even the biggest land
>>>> masses are constantly being reshaped by Earth.
>>>> Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson
>>>> Beck, Ernie Wrigh
>>>>
>>>> [end of blurb for the video]
>>>>
>>>> A really neat feature is that, while pausing the video, you can
>>>> move along the track of the video at your own pace,
>>>> and watch the conjectured path that Greenland took during those
>>>> forty million years.
>>>>
>>>> The hotspot seems to trace a path from the north end of Greenland to
>>>> almost its south end.
>>>
>>> Well, you mean that Greenland seems to trace a path over the hot
>>> spot. It seems as if the mid-Atlantic ridge also must move a bit west
>>> in this scenario, so that Greenland's movement is a combination of
>>> its spreading from the ridge and motion of the ridge. I wonder if
>>> Iceland and the ridge will eventually move off the hot spot, leaving
>>> it to sink while the hot spot gives rise to an island chain
>>> resembling Hawaii.
>>
>> Well you know, what is the motive force that drives plate
>> tectonics?
>
> Mantle convection and slab pull, as I understand it.
>
>> Probably it would involve something on the order of heat
>> convection from the Earth's core.
>>
>> Does the term 'mantle plume' refer to any exact model?
>> If it is unclear exactly what that means then the response
>> ends up 'we don't know'.
>>
>> Is Iceland the center of the motive force opening up the
>> north Atlantic and Arctic oceans?  Maybe?
>
> It's at least situated right on the mid-Atlantic ridge. Whether that's
> the center of the motive force is open to discussion. Why?

Well this seems to be the subject of the thread.

You know I get the idea that the Galapagos Islands
are at the triple boundary between the three major
plates that were diverging under the Pacific Ocean
for a while and are generally still there.

Maybe about 30 years ago after the meteor from
outer space theory came out I read this one article
from Scientific American where it laid out that Iridium
can come from volcanism and that there may have simply
been an extensive period of volcanism at the K-T
boundary that had nothing to do with a meteor. It
proposed or suggested the idea that increased
volcanism could result from the emergence of convective
events from the Earth's core emerging into the upper
mantle at the boundary of the mantle to the crust.

Do you think it feasible that the hot spot under
Hawaii may have once been at the boundary between
two plates that was causing divergence between them,
but now it is weak enough that it can not effectively
oppose the divergence at the Galapagos Islands, or
do you generally think that the source of movement
may be more diffused over a wider distance under the
plates? That article about 30 years ago seemed to
give a lot of evidence that iridium could come
from volcanism as well as meteors, and that there
was no meteor strike at the KT boundary around
that time.

It also might be true that North America was
diverging from from Eurasia prior to that time,
and increased volcanism from the emergence of
a hot spot migrating from the core to the
upper mantle might not be a viable theory of
why the KT boundary was so abrupt. Then again
who knows.

On 12/20/23 1:08 PM, Trolidan7 wrote:
> On 12/20/23 08:01, John Harshman wrote:
>> On 12/20/23 6:54 AM, Trolidan7 wrote:
>>> On 12/19/23 15:15, John Harshman wrote:
>>>> On 12/19/23 2:52 PM, Peter Nyikos wrote:
>>>>> Live Science short video, a bit under 2 minutes
>>>>>
>>>>> https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
>>>>>
>>>>> The gist of it is a hypothesis [1] that Greenland passed over a
>>>>> hotspot
>>>>> between 80 and 40 million years ago, and after it emerged, Iceland
>>>>> was built
>>>>> above the hotspot, where it stands today.
>>>>>
>>>>> [1] not identified as such, but treated as a discovery.
>>>>>
>>>>> Title: Iceland Comes From Greenland?
>>>>>
>>>>> Scientists learn to better understand the movement of Greenland, as
>>>>> it was slowly pushed over the hotspot that is now located under
>>>>> neighboring Iceland.
>>>>> Nothing stands still over geologic time, and even the biggest land
>>>>> masses are constantly being reshaped by Earth.
>>>>> Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson
>>>>> Beck, Ernie Wrigh
>>>>>
>>>>> [end of blurb for the video]
>>>>>
>>>>> A really neat feature is that, while pausing the video, you can
>>>>> move along the track of the video at your own pace,
>>>>> and watch the conjectured path that Greenland took during those
>>>>> forty million years.
>>>>>
>>>>> The hotspot seems to trace a path from the north end of Greenland
>>>>> to almost its south end.
>>>>
>>>> Well, you mean that Greenland seems to trace a path over the hot
>>>> spot. It seems as if the mid-Atlantic ridge also must move a bit
>>>> west in this scenario, so that Greenland's movement is a combination
>>>> of its spreading from the ridge and motion of the ridge. I wonder if
>>>> Iceland and the ridge will eventually move off the hot spot, leaving
>>>> it to sink while the hot spot gives rise to an island chain
>>>> resembling Hawaii.
>>>
>>> Well you know, what is the motive force that drives plate
>>> tectonics?
>>
>> Mantle convection and slab pull, as I understand it.
>>
>>> Probably it would involve something on the order of heat
>>> convection from the Earth's core.
>>>
>>> Does the term 'mantle plume' refer to any exact model?
>>> If it is unclear exactly what that means then the response
>>> ends up 'we don't know'.
>>>
>>> Is Iceland the center of the motive force opening up the
>>> north Atlantic and Arctic oceans?  Maybe?
>>
>> It's at least situated right on the mid-Atlantic ridge. Whether that's
>> the center of the motive force is open to discussion. Why?
>
> Well this seems to be the subject of the thread.
>
> You know I get the idea that the Galapagos Islands
> are at the triple boundary between the three major
> plates that were diverging under the Pacific Ocean
> for a while and are generally still there.
>
> Maybe about 30 years ago after the meteor from
> outer space theory came out I read this one article
> from Scientific American where it laid out that Iridium
> can come from volcanism and that there may have simply
> been an extensive period of volcanism at the K-T
> boundary that had nothing to do with a meteor.  It
> proposed or suggested the idea that increased
> volcanism could result from the emergence of convective
> events from the Earth's core emerging into the upper
> mantle at the boundary of the mantle to the crust.
>
> Do you think it feasible that the hot spot under
> Hawaii may have once been at the boundary between
> two plates that was causing divergence between them,
> but now it is weak enough that it can not effectively
> oppose the divergence at the Galapagos Islands, or
> do you generally think that the source of movement
> may be more diffused over a wider distance under the
> plates?  That article about 30 years ago seemed to
> give a lot of evidence that iridium could come
> from volcanism as well as meteors, and that there
> was no meteor strike at the KT boundary around
> that time.
>
> It also might be true that North America was
> diverging from from Eurasia prior to that time,
> and increased volcanism from the emergence of
> a hot spot migrating from the core to the
> upper mantle might not be a viable theory of
> why the KT boundary was so abrupt.  Then again
> who knows.
>
All that is just wrong. There was a meteor strike; it's call the
Chixculub impact, and it coincides with the iridium anomaly exactly. The
Hawaiian hotspot was never at a plate boundary and has nothing to do
with making plates move.

As for the Galapagos, Wikipedia has this:
https://en.wikipedia.org/wiki/Galápagos_Microplate.

Op 20-12-2023 om 17:01 schreef John Harshman:

> On 12/20/23 6:54 AM, Trolidan7 wrote:
>> On 12/19/23 15:15, John Harshman wrote:
>>> On 12/19/23 2:52 PM, Peter Nyikos wrote:
>>>> Live Science short video, a bit under 2 minutes
>>>>
>>>> https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
>>>>
>>>> The gist of it is a hypothesis [1] that Greenland passed over a hotspot
>>>> between 80 and 40 million years ago, and after it emerged, Iceland
>>>> was built
>>>> above the hotspot, where it stands today.
>>>>
>>>> [1] not identified as such, but treated as a discovery.
>>>>
>>>> Title: Iceland Comes From Greenland?
>>>>
>>>> Scientists learn to better understand the movement of Greenland, as
>>>> it was slowly pushed over the hotspot that is now located under
>>>> neighboring Iceland.
>>>> Nothing stands still over geologic time, and even the biggest land
>>>> masses are constantly being reshaped by Earth.
>>>> Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson
>>>> Beck, Ernie Wrigh
>>>>
>>>> [end of blurb for the video]
>>>>
>>>> A really neat feature is that, while pausing the video, you can
>>>> move along the track of the video at your own pace,
>>>> and watch the conjectured path that Greenland took during those
>>>> forty million years.
>>>>
>>>> The hotspot seems to trace a path from the north end of Greenland to
>>>> almost its south end.
>>>
>>> Well, you mean that Greenland seems to trace a path over the hot
>>> spot. It seems as if the mid-Atlantic ridge also must move a bit west
>>> in this scenario, so that Greenland's movement is a combination of
>>> its spreading from the ridge and motion of the ridge. I wonder if
>>> Iceland and the ridge will eventually move off the hot spot, leaving
>>> it to sink while the hot spot gives rise to an island chain
>>> resembling Hawaii.
>>
>> Well you know, what is the motive force that drives plate
>> tectonics?
>
> Mantle convection and slab pull, as I understand it.

I remember something about top-down tectonics by Ron L. Anderson, and
plate tectonics driving mantle convection.
https://www.science.org/doi/10.1126/science.1065448

See also:
https://doi.org/10.1017/CBO9781139167291

On 12/21/23 1:45 AM, Pandora wrote:
> Op 20-12-2023 om 17:01 schreef John Harshman:
>
>> On 12/20/23 6:54 AM, Trolidan7 wrote:
>>> On 12/19/23 15:15, John Harshman wrote:
>>>> On 12/19/23 2:52 PM, Peter Nyikos wrote:
>>>>> Live Science short video, a bit under 2 minutes
>>>>>
>>>>> https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
>>>>>
>>>>> The gist of it is a hypothesis [1] that Greenland passed over a
>>>>> hotspot
>>>>> between 80 and 40 million years ago, and after it emerged, Iceland
>>>>> was built
>>>>> above the hotspot, where it stands today.
>>>>>
>>>>> [1] not identified as such, but treated as a discovery.
>>>>>
>>>>> Title: Iceland Comes From Greenland?
>>>>>
>>>>> Scientists learn to better understand the movement of Greenland, as
>>>>> it was slowly pushed over the hotspot that is now located under
>>>>> neighboring Iceland.
>>>>> Nothing stands still over geologic time, and even the biggest land
>>>>> masses are constantly being reshaped by Earth.
>>>>> Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson
>>>>> Beck, Ernie Wrigh
>>>>>
>>>>> [end of blurb for the video]
>>>>>
>>>>> A really neat feature is that, while pausing the video, you can
>>>>> move along the track of the video at your own pace,
>>>>> and watch the conjectured path that Greenland took during those
>>>>> forty million years.
>>>>>
>>>>> The hotspot seems to trace a path from the north end of Greenland
>>>>> to almost its south end.
>>>>
>>>> Well, you mean that Greenland seems to trace a path over the hot
>>>> spot. It seems as if the mid-Atlantic ridge also must move a bit
>>>> west in this scenario, so that Greenland's movement is a combination
>>>> of its spreading from the ridge and motion of the ridge. I wonder if
>>>> Iceland and the ridge will eventually move off the hot spot, leaving
>>>> it to sink while the hot spot gives rise to an island chain
>>>> resembling Hawaii.
>>>
>>> Well you know, what is the motive force that drives plate
>>> tectonics?
>>
>> Mantle convection and slab pull, as I understand it.
>
> I remember something about top-down tectonics by Ron L. Anderson, and
> plate tectonics driving mantle convection.
> https://www.science.org/doi/10.1126/science.1065448
>
> See also:
> https://doi.org/10.1017/CBO9781139167291

Got anything that isn't paywalled?

On Tuesday, December 19, 2023 at 6:15:32 PM UTC-5, John Harshman wrote:
> On 12/19/23 2:52 PM, Peter Nyikos wrote:
> > Live Science short video, a bit under 2 minutes
> >
> > https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
> >
> > The gist of it is a hypothesis [1] that Greenland passed over a hotspot
> > between 80 and 40 million years ago, and after it emerged, Iceland was built
> > above the hotspot, where it stands today.
> >
> > [1] not identified as such, but treated as a discovery.
> >
> > Title: Iceland Comes From Greenland?
> >
> > Scientists learn to better understand the movement of Greenland, as it was slowly pushed over the hotspot that is now located under neighboring Iceland.
> > Nothing stands still over geologic time, and even the biggest land masses are constantly being reshaped by Earth.
> > Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson Beck, Ernie Wrigh
> >
> > [end of blurb for the video]
> >
> > A really neat feature is that, while pausing the video, you can
> > move along the track of the video at your own pace,
> > and watch the conjectured path that Greenland took during those forty million years.
> >
> > The hotspot seems to trace a path from the north end of Greenland to almost its south end.

> Well, you mean that Greenland seems to trace a path over the hot spot.

No, in this case, "seems to trace" means "gives the illusion of tracing."
In the video, Greenland seems to rotate a bit in place while everything else is in motion.

Of course, you gave the proper scientific description of the events.

See, John, this is the way mature adults carry on discussions. Ordinary language
is full of ambiguities, and there is no need to dwell on the ones
that are easily clarified like this one was.

> It seems as if the mid-Atlantic ridge also must move a bit west in this
> scenario, so that Greenland's movement is a combination of its spreading
> from the ridge and motion of the ridge.

It isn't clear from anything I've read so far whether Greenland is
spreading from the ridge or merely carried along by the spreading,
the way the whole of North America and Europe are carried along.
Iceland certainly is spreading from it.

> I wonder if Iceland and the
> ridge will eventually move off the hot spot, leaving it to sink while
> the hot spot gives rise to an island chain resembling Hawaii.

I've given this matter a lot of thought these last two days,
spurred on by the following questions.

Is it just a coincidence that the hotspot is right in the middle of the
mid-Atlantic ridge? or that Iceland is bisected by the ridge? or
that the rift valley separating the two halves of the ridge is a prominent
Icelandic (mostly above-ground) feature?

My answer to all three questions is "obviously not." My hypothesis
is that the hotspot, and Iceland, will continue to have this intimate relationship
with the ridge and that Iceland will continue to grow.

If the Atlantic will continue to grow at the expense of the Pacific
for another 150 million years, a whole new (but small) continent
will develop from Iceland. Already it has a substantial
continental shelf that easily triples its area, and covers the ridge
beyond what is readily visible from the air.

I'm really looking forward to a detailed article, or at least a substantial
research announcement, of how all this fits together with Greenland's
having passed over the hotspot while the ridge was forming.
Why, of all places, does the mid-Atlantic ridge have this big bulge,
right near its northern end? Other places where the ridge sticks
above the surface are either tiny (like Tristan da Cunha) or a
bunch of scattered islands like the Azores.

Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
Univ. of South Carolina at Columbia
http://people.math.sc.edu/nyikos

On Thursday, December 21, 2023 at 11:06:27 AM UTC-5, John Harshman wrote:
> On 12/21/23 1:45 AM, Pandora wrote:
> > Op 20-12-2023 om 17:01 schreef John Harshman:
> >
> >> On 12/20/23 6:54 AM, Trolidan7 wrote:

> >>> Well you know, what is the motive force that drives plate
> >>> tectonics?
> >>
> >> Mantle convection and slab pull, as I understand it.
> >
> > I remember something about top-down tectonics by Ron L. Anderson, and
> > plate tectonics driving mantle convection.
> > https://www.science.org/doi/10.1126/science.1065448
> >
> > See also:
> > https://doi.org/10.1017/CBO9781139167291

> Got anything that isn't paywalled?

The latter isn't paywalled for me. My university has institutional access to all parts of the book,
and being on its faculty, I can read the whole thing online.

Can you (meaning anyone who is reading this post) get the table of contents
from where you are? I could look at the places that look most promising to you.

Peter Nyikos

On 12/21/23 10:12 AM, Peter Nyikos wrote:
> On Tuesday, December 19, 2023 at 6:15:32 PM UTC-5, John Harshman wrote:
>> On 12/19/23 2:52 PM, Peter Nyikos wrote:
>>> Live Science short video, a bit under 2 minutes
>>>
>>>
https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
>>>
>>> The gist of it is a hypothesis [1] that Greenland passed over a hotspot
>>> between 80 and 40 million years ago, and after it emerged, Iceland
was built
>>> above the hotspot, where it stands today.
>>>
>>> [1] not identified as such, but treated as a discovery.
>>>
>>> Title: Iceland Comes From Greenland?
>>>
>>> Scientists learn to better understand the movement of Greenland, as
it was slowly pushed over the hotspot that is now located under
neighboring Iceland.
>>> Nothing stands still over geologic time, and even the biggest land
masses are constantly being reshaped by Earth.
>>> Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson
Beck, Ernie Wrigh
>>>
>>> [end of blurb for the video]
>>>
>>> A really neat feature is that, while pausing the video, you can
>>> move along the track of the video at your own pace,
>>> and watch the conjectured path that Greenland took during those
forty million years.
>>>
>>> The hotspot seems to trace a path from the north end of Greenland
to almost its south end.
>
>> Well, you mean that Greenland seems to trace a path over the hot spot.
>
> No, in this case, "seems to trace" means "gives the illusion of
> tracing." In the video, Greenland seems to rotate a bit in place
> while everything else is in motion.
>
> Of course, you gave the proper scientific description of the events.
>
> See, John, this is the way mature adults carry on discussions.
> Ordinary language is full of ambiguities, and there is no need to
> dwell on the ones that are easily clarified like this one was.
>> It seems as if the mid-Atlantic ridge also must move a bit west in this
>> scenario, so that Greenland's movement is a combination of its spreading
>> from the ridge and motion of the ridge.
>
> It isn't clear from anything I've read so far whether Greenland is
> spreading from the ridge or merely carried along by the spreading,
> the way the whole of North America and Europe are carried along.
> Iceland certainly is spreading from it.

Spreading from the ridge and being carried along by the spreading are
the same thing. What I mean is that its distance from the ridge is
increasing while the ridge is also moving west with respect to the
unmoving (more or less by definition) hot spot.

>> I wonder if Iceland and the
>> ridge will eventually move off the hot spot, leaving it to sink while
>> the hot spot gives rise to an island chain resembling Hawaii.
>
> I've given this matter a lot of thought these last two days, spurred
> on by the following questions.
>
> Is it just a coincidence that the hotspot is right in the middle of
> the mid-Atlantic ridge? or that Iceland is bisected by the ridge? or
> that the rift valley separating the two halves of the ridge is a
> prominent Icelandic (mostly above-ground) feature? My answer to all
> three questions is "obviously not." My hypothesis is that the
> hotspot, and Iceland, will continue to have this intimate
> relationship with the ridge and that Iceland will continue to grow.

Why? Based on the track of the hotspot in that video, it hasn't always
been below the ridge, because Greenland has never been on the ridge;
it's continental lithosphere. Iceland, on the other hand, is formed by
the vulcanism of the ridge, which is greater than anywhere else
precisely because there's a hotspot there. The ridge is above sea level
at Iceland because of the volume of lava from hotspot and plate
separation combined. Iceland can't move off the ridge, but the hot spot
can, and eventually will (or rather, the ridge will move off the hot
spot, carrying Iceland with it). You may remember Surtsey, an island
that formed off the coast of Iceland and that is now mostly gone. I
expect more of that; millions of years from now there may be new Hawaiis
in the North Atlantic and two fairly large islands on either side of the
ridge, remnants of the former Iceland.

> If the Atlantic will continue to grow at the expense of the Pacific
> for another 150 million years, a whole new (but small) continent
> will develop from Iceland. Already it has a substantial
> continental shelf that easily triples its area, and covers the ridge
> beyond what is readily visible from the air.

I don't think so. Iceland is not composed of continental rock. It's
oceanic crust. It's like a giant Hawaii. Once the hotspot isn't active
under it, it will eventually have the same fate as the Emperor Seamounts.

> I'm really looking forward to a detailed article, or at least a
> substantial research announcement, of how all this fits together
> with Greenland's having passed over the hotspot while the ridge
> was forming.
That's not while the ridge was forming. It's after the ridge had formed.
That's why Greenland is moving.

> Why, of all places, does the mid-Atlantic ridge have this big bulge,
> right near its northern end? Other places where the ridge sticks
> above the surface are either tiny (like Tristan da Cunha) or a
> bunch of scattered islands like the Azores.

Because a big hotspot happens to have intersected the ridge at that point.

On 12/21/23 1:11 PM, Peter Nyikos wrote:
> On Thursday, December 21, 2023 at 11:06:27 AM UTC-5, John Harshman wrote:
>> On 12/21/23 1:45 AM, Pandora wrote:
>>> Op 20-12-2023 om 17:01 schreef John Harshman:
>>>
>>>> On 12/20/23 6:54 AM, Trolidan7 wrote:
>
>>>>> Well you know, what is the motive force that drives plate
>>>>> tectonics?
>>>>
>>>> Mantle convection and slab pull, as I understand it.
>>>
>>> I remember something about top-down tectonics by Ron L. Anderson, and
>>> plate tectonics driving mantle convection.
>>> https://www.science.org/doi/10.1126/science.1065448
>>>
>>> See also:
>>> https://doi.org/10.1017/CBO9781139167291
>
>> Got anything that isn't paywalled?
>
> The latter isn't paywalled for me. My university has institutional access to all parts of the book,
> and being on its faculty, I can read the whole thing online.
>
> Can you (meaning anyone who is reading this post) get the table of contents
> from where you are? I could look at the places that look most promising to you.

Chapter 7 seemed most promising based on the titles.

On Thursday, December 21, 2023 at 6:24:17 PM UTC-5, John Harshman wrote:
> On 12/21/23 1:11 PM, Peter Nyikos wrote:
> > On Thursday, December 21, 2023 at 11:06:27 AM UTC-5, John Harshman wrote:
> >> On 12/21/23 1:45 AM, Pandora wrote:
> >>> Op 20-12-2023 om 17:01 schreef John Harshman:
> >>>
> >>>> On 12/20/23 6:54 AM, Trolidan7 wrote:
> >
> >>>>> Well you know, what is the motive force that drives plate
> >>>>> tectonics?
> >>>>
> >>>> Mantle convection and slab pull, as I understand it.
> >>>
> >>> I remember something about top-down tectonics by Ron L. Anderson, and
> >>> plate tectonics driving mantle convection.
> >>> https://www.science.org/doi/10.1126/science.1065448
> >>>
> >>> See also:
> >>> https://doi.org/10.1017/CBO9781139167291
> >
> >> Got anything that isn't paywalled?
> >
> > The latter isn't paywalled for me. My university has institutional access to all parts of the book,
> > and being on its faculty, I can read the whole thing online.
> >
> > Can you (meaning anyone who is reading this post) get the table of contents
> > from where you are? I could look at the places that look most promising to you.

> Chapter 7 seemed most promising based on the titles.

I'll be looking it over during my posting break. This is my last post to s.b.p.
before the break starts.

I hope this thread will either resume then or still be going.
I will make the break shorter than usual: less than a full month for sure.

Peter Nyikos

On Thu, 21 Dec 2023 08:06:21 -0800, John Harshman
<john.harshman@gmail.com> wrote:

>On 12/21/23 1:45 AM, Pandora wrote:
>> Op 20-12-2023 om 17:01 schreef John Harshman:
>>
>>> On 12/20/23 6:54 AM, Trolidan7 wrote:
>>>> On 12/19/23 15:15, John Harshman wrote:
>>>>> On 12/19/23 2:52 PM, Peter Nyikos wrote:
>>>>>> Live Science short video, a bit under 2 minutes
>>>>>>
>>>>>> https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
>>>>>>
>>>>>> The gist of it is a hypothesis [1] that Greenland passed over a
>>>>>> hotspot
>>>>>> between 80 and 40 million years ago, and after it emerged, Iceland
>>>>>> was built
>>>>>> above the hotspot, where it stands today.
>>>>>>
>>>>>> [1] not identified as such, but treated as a discovery.
>>>>>>
>>>>>> Title: Iceland Comes From Greenland?
>>>>>>
>>>>>> Scientists learn to better understand the movement of Greenland, as
>>>>>> it was slowly pushed over the hotspot that is now located under
>>>>>> neighboring Iceland.
>>>>>> Nothing stands still over geologic time, and even the biggest land
>>>>>> masses are constantly being reshaped by Earth.
>>>>>> Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson
>>>>>> Beck, Ernie Wrigh
>>>>>>
>>>>>> [end of blurb for the video]
>>>>>>
>>>>>> A really neat feature is that, while pausing the video, you can
>>>>>> move along the track of the video at your own pace,
>>>>>> and watch the conjectured path that Greenland took during those
>>>>>> forty million years.
>>>>>>
>>>>>> The hotspot seems to trace a path from the north end of Greenland
>>>>>> to almost its south end.
>>>>>
>>>>> Well, you mean that Greenland seems to trace a path over the hot
>>>>> spot. It seems as if the mid-Atlantic ridge also must move a bit
>>>>> west in this scenario, so that Greenland's movement is a combination
>>>>> of its spreading from the ridge and motion of the ridge. I wonder if
>>>>> Iceland and the ridge will eventually move off the hot spot, leaving
>>>>> it to sink while the hot spot gives rise to an island chain
>>>>> resembling Hawaii.
>>>>
>>>> Well you know, what is the motive force that drives plate
>>>> tectonics?
>>>
>>> Mantle convection and slab pull, as I understand it.
>>
>> I remember something about top-down tectonics by Ron L. Anderson, and
>> plate tectonics driving mantle convection.
>> https://www.science.org/doi/10.1126/science.1065448
>>
>> See also:
>> https://doi.org/10.1017/CBO9781139167291
>
>Got anything that isn't paywalled?

Sure.

https://sci-hub.se/10.1126/science.1065448

http://library.lol/main/FE8BAA7E7684CD661E621C03D33503E1

See also:
https://www.semanticscholar.org/paper/The-persistent-mantle-plume-myth-Anderson/a5224c926d9bb48381a86df7a06d07535b7e3ff3

On 12/23/23 1:57 AM, Pandora wrote:
> On Thu, 21 Dec 2023 08:06:21 -0800, John Harshman
> <john.harshman@gmail.com> wrote:
>
>> On 12/21/23 1:45 AM, Pandora wrote:
>>> Op 20-12-2023 om 17:01 schreef John Harshman:
>>>
>>>> On 12/20/23 6:54 AM, Trolidan7 wrote:
>>>>> On 12/19/23 15:15, John Harshman wrote:
>>>>>> On 12/19/23 2:52 PM, Peter Nyikos wrote:
>>>>>>> Live Science short video, a bit under 2 minutes
>>>>>>>
>>>>>>> https://www.msn.com/en-us/news/technology/iceland-comes-from-greenland/vi-AA1lE1Fe
>>>>>>>
>>>>>>> The gist of it is a hypothesis [1] that Greenland passed over a
>>>>>>> hotspot
>>>>>>> between 80 and 40 million years ago, and after it emerged, Iceland
>>>>>>> was built
>>>>>>> above the hotspot, where it stands today.
>>>>>>>
>>>>>>> [1] not identified as such, but treated as a discovery.
>>>>>>>
>>>>>>> Title: Iceland Comes From Greenland?
>>>>>>>
>>>>>>> Scientists learn to better understand the movement of Greenland, as
>>>>>>> it was slowly pushed over the hotspot that is now located under
>>>>>>> neighboring Iceland.
>>>>>>> Nothing stands still over geologic time, and even the biggest land
>>>>>>> masses are constantly being reshaped by Earth.
>>>>>>> Credit: Goddard Space Flight Center and Dan Gallagher, Jefferson
>>>>>>> Beck, Ernie Wrigh
>>>>>>>
>>>>>>> [end of blurb for the video]
>>>>>>>
>>>>>>> A really neat feature is that, while pausing the video, you can
>>>>>>> move along the track of the video at your own pace,
>>>>>>> and watch the conjectured path that Greenland took during those
>>>>>>> forty million years.
>>>>>>>
>>>>>>> The hotspot seems to trace a path from the north end of Greenland
>>>>>>> to almost its south end.
>>>>>>
>>>>>> Well, you mean that Greenland seems to trace a path over the hot
>>>>>> spot. It seems as if the mid-Atlantic ridge also must move a bit
>>>>>> west in this scenario, so that Greenland's movement is a combination
>>>>>> of its spreading from the ridge and motion of the ridge. I wonder if
>>>>>> Iceland and the ridge will eventually move off the hot spot, leaving
>>>>>> it to sink while the hot spot gives rise to an island chain
>>>>>> resembling Hawaii.
>>>>>
>>>>> Well you know, what is the motive force that drives plate
>>>>> tectonics?
>>>>
>>>> Mantle convection and slab pull, as I understand it.
>>>
>>> I remember something about top-down tectonics by Ron L. Anderson, and
>>> plate tectonics driving mantle convection.
>>> https://www.science.org/doi/10.1126/science.1065448
>>>
>>> See also:
>>> https://doi.org/10.1017/CBO9781139167291
>>
>> Got anything that isn't paywalled?
>
> Sure.
>
> https://sci-hub.se/10.1126/science.1065448
>
> http://library.lol/main/FE8BAA7E7684CD661E621C03D33503E1
>
> See also:
> https://www.semanticscholar.org/paper/The-persistent-mantle-plume-myth-Anderson/a5224c926d9bb48381a86df7a06d07535b7e3ff3

Thanks. A lot of that is opaque. The Science thing was extra confusing
until I figured out that the figure legends should be swapped.