AHC: Alternate Landmasses

All right, messing around with the islands and continents of earth is not really much of a challenge, I'll admit. Where the challenge does come in is not accidentally butterflying away humanity-so messing with Africa is definitely out, and this probably means that dramatically altering at least the western half of Eurasia and Arabia is also out. That leaves Antarctica, Australia, and North America as continents to mess with. And of course, with all those Pacific and Indian Ocean islands, humanity probably won't notice an archipelago more or less. Obviously, this does stray into ASB territory, but if there are any geologists out there, I would like to hear your opinion as to exactly how outlandish it is to alter Earth's landmass while still allowing Homo sapiens sapiens to exist. Is it totally ASB, or just a little bit?

So, what are your thoughts? Americas that never connected? An Australian continent that did connect to the Asian continent? A more southern Hawaii that provided a stepping stone for a more successful Polynesian settlement of the Americas? A portion of Western North America that separates from the continent a la Madagascar?

Harry Turtledove has already explored this with a dry Mediterranean and an Eastern North American Madagascar (the "Atlantis" series). I'd be interested to hear your thoughts.
 
Well. Seperating the Americas plays merry hell with the currents by allowing a warm current to flow unimpeded from Atlantic to Pacific, thereby preventing the Gulf Stream from fully developing.

Australia was joined to New Guinea during the last ice age, but I can't think of anything off the top of my head to explain why the land stays above water.

A more southerly Hawaii may be tricky given that it's created by a hot spot in the mantle.
 
You could have some fun with Rift Valleys. Most Rifts forms from 3 armed Nexuses. Two active, one 'dead". Thro sometime they shift, with Geoligist not understanding Why.

There is one under the Red Sea. Red Sea/Great Rift/Jordan Rift - With Jordan being the "Dead' one.
If the GR, and Jordan flipped active about 4-5,000^ BP, whe get a very different Eastern Med.

There is a Nexus off the coast of Cote de Ivoire -Cape Verde, Gulf Guinea Islands, dead rift heading North and ending in south Algeria/Libyia.
Have the northern arm be active 15~20 BP and whe have a water channel from the Gold coast to the NAfrica coast.

Then there is a American Gulf Nexus with Texas, & Mississippi being the Active Rifts. Make the two be more active.and whe split the Mississipi Valley, and Texas from Mexico.
 
How about a major iceland-type landmass in the mid atlantic? Or an island scandinavia, like greenland. Or if the Zealandia plateau didn't sink?
 
How about a major iceland-type landmass in the mid atlantic?
One of the Theories about Iceland straddling the Split line of the Mid Atlantic Spread Zone, Involves a slightly larger than Arizona Meteor hitting on the Line - ciria 2-3 million years ago.
It would be possible to POD A second Meteor hitting farther South.

Or an island scandinavia, like greenland.
Have the Glaicer that carved Lake Lagoda [et al] carve a deeper longer channel between the Lakes and reaching to the Sea.

Or if the Zealandia plateau didn't sink?
No Idea accept simply handwavium.

Where the challenge does come in is not accidentally butterflying away humanity-so messing with Africa is definitely out, and this probably means that dramatically altering at least the western half of Eurasia and Arabia is also out.
I would simply Design/Draw my Land Masses, then get Skip to Isot in a few branches from the Homo Bush.
Some Neanderthals here, a few Erutus there. Throw some Peking & Java man tribes around, top off with some Homo Hobbits, and Cro-Magman,
Then sit back and see which tribe comes out on top in TTL.
 
Here are a couple of my ideas I've previously mentioned on the ASB forum (this thread should probably move to there since it involves geological PODs).

Scenario 1:

The Atlantic Rift forms the other side of the Appalachians so that the area remains part of Africa.
Thus Spain also remains joined to Africa and the Mediterranean opens in *Biscay.
I'm not sure what that does to the climate in *Europe and *North West Africa but no reason to believe humans won't still evolve.
The migration out of *Africa might be different though if there is a viable Northwest route - we could even see Northwest Africa settled from Europe.

avaloafrica.gif
 
Scenario 2.
The Avalonian plate collides further west with Baltica with all further rifting as close to OTL as possible.
We thus get more of the Avalonia plate east of the Atlantic rift.
Europe and the Mediterranean are now quite different - there is the potential for the Med to be composed of 3 seas and a much greater chance of human settlement through *Sicily and *Crete since they are closer to North Africa.

Though human evolution is less affected than Scenario 1, Mediterranean history is vastly different and more complicated.

Euravalon Worldmap.PNG
 
The Atlantic Rift forms the other side of the Appalachians so that the area remains part of Africa.
Thus Spain also remains joined to Africa and the Mediterranean opens in *Biscay.
I thought the Appalachians were part of the same mountain range as the Urals. ?When was it hooked to Africa?
 
...the ASB forum (this thread should probably move to there since it involves geological PODs).

Not necessarily, see the following post:
https://www.alternatehistory.com/discussion/showpost.php?p=2159636&postcount=15

One thing I've tried to play with in the past is a surviving Lake Bonneville in Utah, as well as other large lakes in Nevada. I just can't figure out how to do it without also keeping the ice age going another ten thousand years and messing up civilization.
 

FDW

Banned
Not necessarily, see the following post:
https://www.alternatehistory.com/discussion/showpost.php?p=2159636&postcount=15

One thing I've tried to play with in the past is a surviving Lake Bonneville in Utah, as well as other large lakes in Nevada. I just can't figure out how to do it without also keeping the ice age going another ten thousand years and messing up civilization.

Keeping Lake Lahontan around would be doable (in fact, the lakes basin would be refilling itself if not for all of the water that's being taken out of it's watershed. Lake Bonneville is a bit harder, though I think it's draining was caused in part by erosion of it's shorelines causing most of it's water to drain out.
 
No, the mighty Mississippi would just begin elsewhere, perhaps the headwaters of the Minnesota.

More likely one of the dozens to hundreds of other streams and lakes in Northern Minnesota that feed into the Mississippi after Lake Itasca.

For that matter, this is an even easier POD, as it's more cultural than geographical. Just have Schoolcraft decide to establish the source at some other lake on another tributary... he might still call it Itasca, though (a neologism from the Latin "veritas caput", true head, not any Native American word). Or, for that matter, decide that the rivers feeding into some other lake downstream, such as Leech Lake (Zebulon Pike's vote for the source), aren't big enough to be considered part of the Mississippi.

Heck, a little different French exploration might just decide that the Mississippi feeds into the Missouri near St. Louis, instead of the other way around.
 
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195 Million Years Ago in the Jurassic.
Not quite, the Appalachians are at least 400 million years old and the Urals are about 300 million years old. Also, the Appalachians were the same as the Atlas in Morocco while the Urals formed when Siberia smashed Kazakhstan into Baltica.
 
Scenario 2.
The Avalonian plate collides further west with Baltica with all further rifting as close to OTL as possible.
We thus get more of the Avalonia plate east of the Atlantic rift.
Europe and the Mediterranean are now quite different - there is the potential for the Med to be composed of 3 seas and a much greater chance of human settlement through *Sicily and *Crete since they are closer to North Africa.

Though human evolution is less affected than Scenario 1, Mediterranean history is vastly different and more complicated.

That scenario looks fun.
 
Not quite, the Appalachians are at least 400 million years old and the Urals are about 300 million years old. Also, the Appalachians were the same as the Atlas in Morocco while the Urals formed when Siberia smashed Kazakhstan into Baltica.

Well I wasn't going by how old the Appalachians were and when they formed but roughly when they were still joined the Atlas range in Af

That scenario looks fun.

Feel free to play with it :D
 
Not necessarily, see the following post:
https://www.alternatehistory.com/discussion/showpost.php?p=2159636&postcount=15

One thing I've tried to play with in the past is a surviving Lake Bonneville in Utah, as well as other large lakes in Nevada. I just can't figure out how to do it without also keeping the ice age going another ten thousand years and messing up civilization.

Fair enough. It's not ASB so long as we take ripples/butterflies properly into account.
 
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