Apparent Polar Wander vs True Polar Wander:

Apparent polar wander (APW) occurs as the magnetic pole drifts about the surface of the Earth, this is why your compass needs to account for declination. APW is associated with reversals of the geomagnetic field. True Polar Wander (TPW), on the other hand, is a re-orientation of the solid Earth as a whole relative to the spin axis. On Earth, TPW is achieved by wholesale rotation of the solid, silicate Earth (mantle and crust) around the liquid outer core. As Earth’s magnetic pole is tied primarily to rotationally induced excitations of the outer core, the magnetic poles remain aligned with the rotation axis through a TPW event. For example, 90° of TPW could result in Antarctica moving to the equatorial region, Africa moving to the pole, and all other geographic features moving accordingly. Theoretical constraints demonstrate that TPW can occur quite rapidly, limited to approximately 61° in 100 million years (Ma) and 8° in 10 Ma (Theoretical constraints on true polar wander). 1° latitude ≈ 111 km. 61° per Ma ≈ 6771 km per Ma or 677.1 cm per year and 8° in 10 Ma is ≈ 88 cm per year. Those rates are exceptionally fast when compared to tectonic speed limits (Tectonic speed limits from plate kinematic reconstructions) and modern rates of plate motion; The Cocos and Nazca plates (in the pacific ocean) are right now the quickest, moving at over 10 cm per year.

EDIT: An analogy for further clarity and distinction between APW and TPW: Think of a hot slice of cheese and pepperoni pizza with a laser pointing up from below. The pizza sauce is Earth's mantle, and the cheese and pepperoni toppings are the continents. If you were to shoot a laser upwards, from below the pizza slice, you could trace the movement of the laser by looking at the trail it left behind on the toppings. In this scenario, the magnetic pole (the laser) moved but the continents (the toppings) remained in their positions. TPW on the other hand would be like picking up a hot slice of pizza and the toppings all sliding off in one direction at the same time. The laser from below would still leave a trace on the toppings but this time it was the toppings that moved instead of the laser.

Research Paper: On an Extensive Late Hydrologic Event in Gale Crater as Indicated by Water-Rich Fracture Halos

What I find interesting is the fault(s) depicted in the mantle. At those depths, beyond the brittle-ductile transition I would have expected the rocks to deform plastically as opposed to brittle deformation. Is it mylonitic? Can mylonites have seismicity?

Edit:

As previously assumed, brittle deformation doesn't occur in the lithospheric mantle so I think it's assumed that seismic anisotropic reflectors (generated from crystallographic preferred orientations) in the lithospheric mantle arise from grain size reduction via dislocation and diffusion creep along grain boundaries. These seismic anisotropic reflectors are thus interpreted as fine grained mylonitic shear zones and thus downward extensions of brittle faults across the brittle-ductile transition from the crust into the mantle.

Now I'm curious as to how these mantle shear zones, a ductile feature in a ductile regime, remain long lived enough to act as pathways for magma ascent...

Saying it gets to the surface doesn't explain how it gets to the surface, and if I asked you to draw the plumbing system for its pathway to the surface I'd be willing to bet that you'd be pretty far from the truth. This study helps resolve that plumbing system which was pretty uncertain previously.

Socratic questioning

To be clear, we're talking about an eruption of magma not hot water out of a cm scale borehole.

People have drilled directly into magma before (Hawaii in 2007? & Iceland 2009), and there has been no eruption for a couple of reasons:

(1) drill holes are too narrow to transmit the explosive force of a volcanic eruption. (It’s the equivalent of piercing a champagne cork with a pin rather than removing the entire cork at once.)

(2) Due to the small diameter of drill holes (typically <10 cm), the small amount of magma that could flow into the shaft would solidify long before reaching the surface

See Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma for more information.

>Possibly the risk of causing an eruption

How would it cause an eruption (especially considering it can't erupt because its only up to 20% melt fraction)?

Research Paper: Magma accumulation at depths of prior rhyolite storage beneath Yellowstone Caldera

> It's incredibly easy to see areas that have older ice breaks that have completely shifted due to later plate shifting.

That's not true at all as is evident from the article itself had you cared to read it:

"... to best reconstruct the motion of the surface, large areas suspected to be plates in previous studies had to be broken into smaller subplates along less obvious boundaries. This observation helps explain why some prior studies found that large plates did not reconstruct well or behaved in other unexpected ways..."

>Not sure why someone would write a paper on something that's already so well known and easily seen / understood.

Contrary to your claim, this subject is not well known, easily seen or understood and is why researchers continue to refine their models. The fact is that this is still a very new subject (plate tectonics via ice) with little data comparatively speaking. I'll further add that plate tectonics on Earth is still a subject that continues to be refined as new methods are developed, and more data presented.

Research Paper (open access): Episodic Plate Tectonics on Europa: Evidence for Widespread Patches of Mobile-Lid Behavior in the Antijovian Hemisphere

You're missing the forest for the trees, and they hint as much as well. No singular piece of evidence can be used as proof of an ancient civilization because it's likely too difficult to distinguish from natural lines of evidence of an identical nature; however, as I said earlier, and as they say in the paper, combining several lines of evidence can distinguish from natural events such as carbon isotope excursions with a large long-lived radiogenic isotope excursion (^(244)Pu and ^(247)Cm), and perhaps plastics as well.

I might add that the paper doesn't really dive into quantity too much with stable isotopes, though I believe it could benefit from that analysis. What I mean by this is that while they discuss abrupt events (hyperthermals), they don't really go into abrupt abrupt events. For example, while they discuss ^(13)C excursions such as the during the PETM they don't note the difference in carbon flux between that event and modern day climate change. For example, the PETM released roughly 3000 Petagrams of carbon over a period of ~6000 years. It is hypothesized that under a worst-case-scenario our civilization could release 5000 Petagrams of carbon over a period of 500 years. There is nothing in the geological record that even comes close to those values on global scales. On a yearly basis the PETM rates range from about 0.3 to 1.5 Pg C/year. For comparison, the current rate of carbon release to the atmosphere is nearly 10 Pg C/year. And of course the more lines of evidence one uses the more clear the picture becomes.

As for Mars, I'm not quite sure what dating techniques become irrelevant. Absolute dating methods would work just as well on Mars as they do on Earth, and Martian meteorites as well as lunar samples have been dated using radiometric techniques.

>...two scientists (one is a director of NASA’s climate studies and another is an astronomer and physicist, IIRC) argued that there could have existed an ancient industrial civilization on Earth long enough ago that we wouldn’t be able to gather sufficient evidence of its existence due to limitations of dating techniques.

That's not what they argued. The take away was that any ancient civilization would be detectable through large, abrupt, isotope excursions (anomalies). For example our civilization will eventually be compacted into a thin sedimentary layer; however, stable isotope anomalies of carbon, oxygen, hydrogen and nitrogen will be detectable - discerning them from natural excursions may prove difficult though other biomarkers would help shed light on the full story. Plastics, fossils, and radioactive isotopes in conjunction with the former (among a few others) would surely be a clear indicator of an ancient civilization.

You can read the full study here: The Silurian hypothesis: would it be possible to detect an industrial civilization in the geological record?

I'm not sure what you heard exactly but the reality is that unfortunately it's simply not possible.

Setting aside the difficulties of transporting the ludicrous amounts of nuclear warheads required to heat that much rock, how would you deliver the nuclear warheads to the required depth even if you could get them to Mars?

The deepest hole on Earth (Kola Superdeep Borehole) took about 21 years(?) of active drilling to reach a depth of ~12 km. At that point drilling was too difficult to continue as temperatures were hotter than expected and the rock began to behave like a warm plastic so the hole would collapse on itself (on Earth there's a transition zone where rocks go from behaving in a brittle fashion to behaving in a ductile fashion known as the Brittle-Ductile Transition Zone, this transition will exist on every rocky planet at slightly different depths). To reach the core of Mars, you'd need to drill down ~1,560 km. That means that on Earth, the Kola Superdeep Borehole managed to reach an equivalent of 0.7% of the way to the Martian core. Just over half of 1%.

Hopefully that helps paint a partial picture as to why the idea of restarting the magnetosphere on Mars has no basis in reality.

That's not how self sustaining geodynamos work

It's more to do with size, as smaller bodies will loose their heat to space more rapidly than larger bodies. However, even this assumption has led to some surprises. The moon, for example, was once thought to be solid - far too small to retain any heat today - but recently was found to have a fluid outer core and mantle with partial melt. Ultimately, as magma rises due to its buoyancy relative to the surrounding mantle rock, the moon may actually become volcanically active in the future if the partial melt continues to rise upwards through its mantle before it solidifies.

Research Paper: Tectonics of Cerberus Fossae unveiled by marsquakes