Reconstructing Eorzea's geological history.

[Myranda]

I'd be inclined to go with the long history and slow (read: normal) drift myself, with the eras only referring to recorded history. I'm on board with you that the creation myth isn't literal creation of Hydaelyn, but only the citizens current idea of it given their stage in technological advancement (barely any know what a planet is after all).

Also, if Silvertear really is an impact basin, maybe we ought to search the strata for rare elements (a la KT boundary iridium). If it is an impact though, either the local rock is highly resistant to erosion, it's a relatively recent impact, or the aether concentration is interfering with the erosion, preserving it.

I'm also surprised the Coerthas River isn't marked on the world/regional map. But I'd guess it doesn't flow into Silvertear. Nothing seems to flow into or out of it actually with the White Maiden skirting around the NW mountains, but it's also not a highly detailed map...

In fact it looks like after the Coerthas joins with Swiftrun at the Riversmeet confluence (see Coerthas map), they fall off into the Sea of Clouds at Greytail Falls and presumably flow north to the Farreach. Of course, that's based on 1.x maps and ARR may have changes in store for us, especially considering the massive topology changes Bahamut hath wrought.

Also based on the world/region map, I'd guess the Coerthas mountains' uplift is a result of Sharlayan/Dravania/Farreach plowing into the rest of Aldenard. I don't think Mor Dhona is being subducted, seems more continental on continental buckling which creates the tallest mountains anyways. However, if Vylbrand is part of the Dravanian plate, the seafloor of the Strait of Melthor could be closing up and that portion of subduction is driving O'Ghomoro?

The area between Thanalan and the Shroud is also marked by smaller mountains, hinting that Thanalan joined Aldenard at an earlier time in history and has since eroded down somewhat (which could support Thanalan having been an equatorial rainforest previously as you stipulated, since Eorzea is now roughly centered at 30°N).

[Catapult]

Also based on the world/region map, I'd guess the Coerthas mountains' uplift is a result of Sharlayan/Dravania/Farreach plowing into the rest of Aldenard. I don't think Mor Dhona is being subducted, seems more continental on continental buckling which creates the tallest mountains anyways. However, if Vylbrand is part of the Dravanian plate, the seafloor of the Strait of Melthor could be closing up and that portion of subduction is driving O'Ghomoro?

The area between Thanalan and the Shroud is also marked by smaller mountains, hinting that Thanalan joined Aldenard at an earlier time in history and has since eroded down somewhat (which could support Thanalan having been an equatorial rainforest previously as you stipulated, since Eorzea is now roughly centered at 30°N).

Even in continental buckling, there is a plate that is technically subducting. It just gets crumpled up in the process. In the Himilayas, India is dominated by China (sorry, politics) in a continuation of what was once ocean subducting beneath the Tibetian coastline.


Such a setup would put any potential volcanos on the Sharlayan side of the boundary rather than the Vylbrand side.
The local geology also suggests that O'ghomoro is more of a hot-spot-style volcano.

Of course, there can always be something more complex going on. ^_^

[Skies]

[*]Thanalan Caves
Thanalan is riddled by a network of tunnels that appear to have been naturally formed. In some locations, such as West Thanalan, these tunnels have opened up and connected with the surface. The presence of water suggests they are formed by subterranean water flows. (can someone find me a real-world comparison?)
The mineral composition suggests rocks of felsic origin (mostly granites) that have undergone metamorphism through burial before erosion.
The specific combination with amber (fossilised tree sap) suggests sedimentary deposits at least where this mineral is found (cave systems are easier formed in sandstones of eroded pegmatites rather than the original rock). In a previous age, parts of Thanalan would have had a very lush vegetation (wider historical coverage of the Twelveswood?).

I am unforunately no moose foutain of knowledge, however. I do certainly have in my memory at least on NPC that mentions that Thanalan was once a more lush and green place. In fact if memory serves me it was a gridanian who said it, attributing the desertification to the fact that the denizens of Thanalan would effectively hunt their Elementals.

Now you mentioned continental drift. I'm not trying to suggest that the uplift of the Coerthas mountains happened in the space of a few thousand years (the earthquakes would be civilisation-breaking). I'm suggesting that it's been going on since "creation".

Part in bold. The earth-elemental umbral era, anyone?