Geffyl wrote:

Ghul wrote:

Geffyl is actually touching on what I was imagining when I came up with the hexagonal cut of Hyperborea, with a black obelisk at each point. The separation of the continent from Old Earth remains a thing only vaguely alluded to in the descriptive text of the setting material, but one thing I did study while making some of these choices was the continental shelf of the Arctic Ocean, specifically the depth of its basins and sub-basins. Imagine, if you will, that entire basin having been at one time occupied by a continent that roughly conforms to our Hyperborea's size, and maybe close to connecting to Greenland. Now, imagine that "plate" ripped from, or teleported, or launched from (whatever yhou might imagine!) Earth, leaving behind a series of basins of substantial depth. At present, the deepest of these basins is nearly 4,000 meters. That's almost 2.5 miles. These numbers do not need to dictate how we imagine the depth of the oceanic and continental crusts, but they are (to me!) interesting points of reference.
 

I try my best, Ghul.

I admit to not  being a master of tectonophysics, but I researched the general information available on continental  crusts (avg 25 - 40 km) and oceanic crusts (avg 5 - 10 k m). I also looked into several of Old Earth's larger mountain ranges, noting the "root" thickness of the tectonic plates, which are  nearly double of the average thickness for the rest of the planet.

I imagined Hyperborea to be removed almost like a lense from an eyeball, generally concave in a hexagonal shape. Afterall, Old Earth wasn't left with a flat top. More likely, any violent removal may have left Old Earth filling in the wound as much as it could beneath molten core and the settling oceans, leaving basins of a seeming lesser depth than the original land's removal.

Magical and extradimensional forces withstanding, it's not a perfect estimate. YMMV.

Ciao,
Geffyl

Yes, I could imagine that any violent extraction of the plate would not just leave a perfect hole to match what was there -- it would be more like you suggest, with collapses and settling and so forth. Great observation! BTW, if you can, always alert us here on the forums when you add a new blog post!

 

ThornPlutonius wrote:

Go down deeply enough and you may well find the vast primordial machinery that keeps Hyporborea behaving like a living planet: cycling the oceans' water, recycling the air, generating the force field that holds the atomosphere above the "disc".  Oh, and then there are the beings who live to keep that machinery working...

I might steal this and put it in the underborea campaign.

Ghul wrote:

If such beings exist, I know just who they might be, but I'm keeping my hand close to my chest. Can I be any more unclear? ;)
 

Some mysteries are best subtly hinted at through careful foreshadowing that is only recognized as the full horror of the final reality sears the discoverer's mind.

grodog wrote:

The underside of Hyperborea definitely plays into the the dungeon and wilderness environ I was working on this fall.  If I have time to work on it further, I'll try to playtest some of it at GaryCon.  We'll see....

That would be fantastic, Allan. I'd be honored to have a DM of your reputation running a little Hyperborea. Thank you for considering it!