The systematic topographic decay along the Snake River Plain, totaling 1,300 m, fits a model of lithospheric cooling and subsidence which is consistent with passage of the North American plate across a mantle heat source.
The 16-0 Ma rate of 4.5 cm/yr silicic volcanic, age progression of the YSRP includes a component of southwest motion of the North American plate, modeled at ∼ 2.5 cm/yr, and a component of concomitant crustal extension estimated to be 1 to 2 cm/yr.
Direct evidence for a mantle connection for the YSRP system is from anomalously low, P-wave velocities that extend from the crust to depths of ∼ 200 km.
These properties and the kinematics of the YSRP are consistent with an analytic model for plume-plate interaction that produces a “bow-wave” or parabolic pattern of upper-mantle flow southwesterly from the hotspot, similar to the systematic patterns of regional topography and seismicity.
Anomalously low P-wave velocities in the upper crust of the Yellowstone caldera are interpreted as solidified but still hot granitic rocks, partial melts, hydrothermal fluids and sediments.
Unprecedented deformation of the Yellowstone caldera of up to 1 m of uplift from 1923 to 1984, followed by subsidence of as much as ∼ 12 cm from 1985 to 1991, clearly reflects a giant caldera at unrest.
If it even exists in the same dimension as our Insignificant Little Blue Planet, chances are it's either outside the world entirely (and often accessible only by a Cool Gate), or located in a strange, unknown corner of the Earth. If so, expect at least one character, upon seeing it, to widen his eyes and gasp: "What is this place?!
" The Big Bad may set up A Very Definitely Final Dungeon or an Amazing Technicolor Battlefield here.
Eldritch Locations take many forms: Lost Worlds, Wonderlands ("Wonder" is not always a good thing), Strange Planets, Incomprehensible Voids, the insides of Eldritch Abominations, Alternate Universes, ordinary-looking buildings...
Our unified model for the origin of the YSRP is consistent with the geologic evidence where basaltic magmas ascend from a mantle plume to interact with a silicic-rich continental crust producing partial melts of rhyolitic composition and the characteristic caldera-forming volcanism of Yellowstone.
Cooling and contraction of the lithosphere follows the passage of the plate over the hotspot with continuing episodic eruptions of mantle-derived basalts along the SRP.
The ones that aren't are usually sources of Surreal Humor.
If this place is a planet or country, then it will often feature an Alien Sky, as well as Mix-and-Match Critters or Starfish Aliens by the herd.