How was the weather on Pangea like?

[jokergirl]

Hey, Earth is a planet too, and this question just popped up in my mind while watching another of those continental drift illustrations...

Well, top of my head, I would have said, a)dry and b)stormy. Let's get the facts clear so we can build up assumptions (and let's pretend we are thinking up a possible alien world so the BA will let this stay) ;)

We have a HUGE landmass that stretches from pole to pole; apart from that it's rather flat compared to what we have now. This would indicate *very* continental climate.
A quick Google search brought up this article (http://geology.ou.edu/library/earthscientist/Winds%20of%20Western%20Pangea.pdf) which suggests monsoons, climate zones and strong seasonality and brings up the idea that the landmass interrupts normal zonal circulation patterns, which might make the weather even more extreme.

Toto, I don't think we're in Gondwanaland anymore...

Anybody got an idea where you could get simulations of that? Any other suggestions on influences on the weather there?

;)

[eburacum45]

Fascinating stuff. The centre of Pangaea will have been further from any ocean than any land area on Earth today, so may well have been at a very high temperature- perhaps 150F or more-
and the oceanic side of the world might have developed El Nino type wind and current flows-
but the sort of circular flow which develops in the Great Southern Ocean today might not be able to develop, unless the poles themselves were covered in ocean; you might get some interesting circular flows developing in that case.
Another thing that might affect the Pangaean climate and circulation is the level of carbon dioxide in the atmosphere- it is possible that the CO2 level was ten times that of today's earth;
based on the size of Mesozoic leaf stomata.
This might have acted as a greenhouse gas to an extent, raising the temperature still further, increasing the cloud cover and perhaps increasing the albedo of the Earth somewhat; however with no ice caps the appearance of Earth might have been quite different.

Earth in fact was a very different planet then.

[glen chapman]

Discovery channel have a series running (In Aust, so it might be old news in the US) Called the future is wild. In one of the episodes they run a Pangaea senario - set 100 million years in the future.

While there evolution extrapolations look a bit dusty 200 ton shelled creatures and such, the climate seemed to fit well with what paleo-botanists have been saying about the last time the continents had a big hug fest.

Glen

[Humphrey]

The general rule of clumate is that the further you get from large bodies of water, the drier it is and the more varied the weather gets. So in those areas you will get massive swings from cold winters to very hot summers.

[Argos]

It´s interesting to note that Pangea formed three times, at least, during Earth´s life. Right now the continents are still moving. Since they got nowhere to go on the surface of the Earth, it´s possible that they´ll be together again in the future.

[Humphrey]

It´s interesting to note that Pangea formed three times, at least, during Earth´s life. Right now the continents are still moving. Since they got nowhere to go on the surface of the Earth, it´s possible that they´ll be together again in the future.

Not possible, definite. :-)

[DStahl]

At the same time, the jet streams tend to hose the northern part of our continents with storms and keep them fairly well-watered (less so the southern?). So coastal Pangea at high latitudes might have been very wet (like Seattle but warmer, if we take the CO2 evidence at face value) while the interior may have had some large deserts? Also, hot atmosphere plus large ocean expanses might be expected to breed spectacular cyclonic storms, I would think. Superhurricanes might have been a fact of life along the Pangean tropical coastlines.

[Colt]

Websites seem to concur with the general idea everyone is putting forth. -Colt

[Argos]

Superhurricanes might have been a fact of life along the Pangean tropical coastlines.

Yes. The ocean surrounding pangea must have been much larger. There would have been much room for a storm gaining momentum, much like what happens in the Atlantic, with the storms that begin as low pressure eyes at the African coast. The hurricanes in Pangea should sweep half the planet when they formed.

[Argos]

Superhurricanes might have been a fact of life along the Pangean tropical coastlines.

Yes. The ocean surrounding pangea must have been much larger than today´s. There would have been much room for a storm gaining momentum, much like what happens in the Atlantic, with the storms that begin as low pressure eyes at the African coast. The hurricanes in Pangea should sweep half the planet when they formed.

Edited for fixing error

[kilopi]

Are you guys forgetting about the great inland shallow seas that developed during some of those times?

I just googled this, and found an online copy of This Dynamic Earth (http://pubs.usgs.gov/publications/text/dynamic.html) on the USGS site. It didn't have any maps of the inland seas, like I was looking for, but it did have a page on Some Unanswered Questions (http://pubs.usgs.gov/publications/text/unanswered.html) concerning Plate Tectonics. It points out the relative lack of evidence for tectonics on other planets, and that the mechanism of plate tectonics is still a bit of a mystery.

I'm going to take this opportunity to expand on theory number three (http://www.badastronomy.com/phpBB/viewtopic.php?p=6187#6187), as I plan to write a short article soon.

The Unanswered Question page above mentions Harry Hess, who came up with the idea of sea-floor spreading in the early sixties. In Hess's famous article, which has been cited over a thousand times, he twice makes the claim that Subramanyan Chandrasekhar proved, in the early fifties, that there could be no degree-one convection in the Earth. I was lead to read the article because I was convinced that degree-one convection was a solution to the plate tectonic problem, but some articles written by geophysists in the late seventies mentioned that degree-one convection was impossible and cited Hess's article.

When I read Chandrasekhar's paper, I discovered that Hess had misinterpreted Chandrasekhar's paper, and far from proving that degree-one was impossible, it actually showed that degree-one was almost certain, and probably dominant. I discovered that Chandrasekhar had included the results in his classic Hydrodynamic and Hydromagnetic Stabilty (http://www.amazon.com/exec/obidos/tg/detail/-/048664071X/104-1745909-2627132?vi=glance), published just a couple years before Hess's paper. I considered the possibility that there had been some developments in the two year span, but I couldn't find any.

I decided to try to communicate with Chandrasekhar, and called his office to get permission and an address. He answered his own phone, and we had a nice talk. He concurred with my assessment of Hess's claims. When he had finished his book, he boxed up all his notes, put them on a shelf, and never returned to the topic. He didn't even follow the subsequent development, or references to his work, so he had had no idea of the claims that the geophysicists were making about his work.

So, you can imagine all the continents accumulating on one side of the globe, but the accumulation is gradually unbalanced until the convection flops to the other side (in first approximation). Then, everything breaks apart and moves to that other side, then repeats. The viscosity of the mantle does not have to be as low as the usual convection model would require--which is contradicted by other evidence--as the continents would not be driven by convection so much as a gravity gradient. Their motion would be coupled with, but distinct from, the motion of the ocean floors. There would be a "backflow" as the deep continents displaced shallow mantle.

Interestingly, Walter Alvarez, who with his father Louis came up with the theory of impact extinctions, had stumped for the idea of backflow for years with no success. He told me that he didn't even get criticism! Either no one understood his model, or they dismissed it as ridiculous immediately. His idea was based upon surface evidence, rather than any theory of convection, and was first suggested by the appearance and then characteristics of the sea floor (http://www.ngdc.noaa.gov/mgg/image/2minrelief.html) between South America and Antarctica (http://mensware.home.mindspring.com/dan/saanflow.jpg) and between South America and North America (http://mensware.home.mindspring.com/dan/sanaflow.jpg) and in the southwestern Pacific.

[Colt]

I'll come back and read your entire post later, kilopi, but at the moment a I can think of for Earth having tectonics still: We are the only planet with a moon as large as ours compared to the planet. Maybe this is it?

I'm going to feel really dumb if I am forgetting something. -Colt

[DStahl]

Interesting, Kilopi! Will you be able to post a copy of the article after it's published, do you think?

kilopi: "Are you guys forgetting about the great inland shallow seas that developed during some of those times?"

I imagine so, and I 'spect that Pangea would also have substantial landlocked drainage basins. But that's hard to post-dict. I also suspect that it had at least some major mountain ranges--wouldn't they form along some of the sutures when the pre-Pangea continents came together?--and there would create the usual montane wet zone and down-weather rainshadow. But again, without specifics it's hard to know what the climate specifically looked like. At least it is for me.

[Anonymous]

Regarding paleo-climatology, a couple of informative maps found here;

http://www.clearlight.com/~mhieb/WVFossils/Carboniferous_climate.html

and here; http://www.scotese.com/climate.htm


This one is also noteworthy. It has maps going back to the super continent which preceded Pangia, named “Rodinia”.

http://www.uwgb.edu/dutchs/platetec/plhist94.htm

And yes, an earlier super continent has been proposed named “Columbia”.

http://www.altacolumbia.com/pages/geology.html

Can I get a witness? Wasn’t there a model making the rounds that the ancient cratons were actually fragments of one, original super continent named “Ur”?

[eburacum45]

Fantastic palaeoclimate links!
I was particularly interested in the Carboniferous climate as shown
on these maps
http://www.scotese.com/bashclim.htm
it seems the CO2 was quite low, and the global temperature was similar to today; the Pangean continent covered the south pole, so there was probably an ice cap; and the Tethys sea seems to have been surrounded by tropical rain forests.
I suppose the carbon was mostly bound up in biomass in those days (apart from the carbon sequestrated in rocks, which was, and is, the greater part)- I have even heard tell that the O2 level was higher in the Carboniferous, allowing large arthropods to evolve including Megarachne and Arthropleura.

[Argos]

I decided to try to communicate with Chandrasekhar, and called his office to get permission and an address. He answered his own phone, and we had a nice talk.


What a courage! I could hardly talk with him without trembling. It is not everyday that you meet a Nobel winner

Seriously though, Kilopi posted a very informative material. Earth's geology is something closely related to planetary sciences in general, the reason why I think that a certain latitude should be allowed for this kind of subject in this forum.

[eburacum45]

Absolutely.
We only have a sample of one when it comes to Earth-type worlds;

but the Earth has been so different over its four billion year history
(many different levels of O2 and CO2, not to mention the original reducing atmosphere)
that it can represent several different potential planets that we may one day detect.

[Diamond]

I don't know about next time, but last time it happened Pangaea was a huge desert that had regular mega monsoons. There was no land-based life at the time, but it was a pretty hostile place.

D.

[nebularain]

I also suspect that it had at least some major mountain ranges--wouldn't they form along some of the sutures when the pre-Pangea continents came together?

Weren't the Appalachians formed that way?

[DStahl]

Yes, nebularain, I believe you are right. According to one of the links posted above, some people feel confident enough to mark some general areas as mountainous on a map of Pangea.

Kilopi, I too am impressed by your talking with Chandresekhar. From what I have read he gives real meaning to the phrase "gentleman and scholar."

[kilopi]

It's incredible how accessible some people are, even for us maggots. But it helps to bring up some sort of interesting oddity to pique their interest. I once received a personal email from Brian Josephson, he said "power to the elbow of FSS (http://mentock.home.mindspring.com/fss.htm)." I've exchanged some email with John Gribbin, and talked on the phone with Jared Diamond, Stephen Jay Gould, and Clifford Will.

[Humphrey]

You talked to Gould?!?! :o Lucky stiff. :-) You are one very lucky man you know that?

[Kebsis]

If the continents continue to drift away from each other until they eventually collide into each other again, and keep on pushing into each other, wouldn't at one point Pangea be just one massive mountain?

[kilopi]

At some point, they start pushing back.

[aurorae]

If the continents continue to drift away from each other until they eventually collide into each other again, and keep on pushing into each other, wouldn't at one point Pangea be just one massive mountain?

India is making some massive mountains, but Asia is a really big plate.

[Candy]

It´s interesting to note that Pangea formed three times, at least, during Earth´s life. Right now the continents are still moving. Since they got nowhere to go on the surface of the Earth, it´s possible that they´ll be together again in the future.
Interesting thread. I wonder why no one expanded on Argos' theory?

<-Queen of resurrection! http://www.bautforum.com/images/icons/icon11.gif

[Kristophe]

I'm not sure how much expanding there is to do, other than to wish California well while hanging out with Alaska and Siberia.

Ahh, to not be living on a major plate boundry.

[Maddad]

If the continents continue to drift away from each other until they eventually collide into each other again, and keep on pushing into each other, wouldn't at one point Pangea be just one massive mountain?That cycle is supposed to take about 400 million years.