2049ers: The Martian Gold Rush

Factual Questions
1

As a writer and gamer, I think GURPS sourcebooks are an invaluable aid to the imagination.

I have been reading GURPS Mars, which discusses every aspect of Mars in science and fiction.

In one section, the authors offer the adventure possiblilties of a gold rush on Mars. I quote:

And then the line that piqued my interest:

However, nowhere in the science part of the book do the authors mention what gemstones we might find on such a geologically inactive planet.

I have since checked the ** Out of the Cradle **, A Traveler’s Guide to the Solar System, and The Planets: A Smithsonian Guide, and none has said anything about what sort of gems might be found on Mars.

I think the gold rush idea is very interesting, so I look to the geologists and planetary scientists of the SDMB for help.

What treasures might await us?

[sub]fixed coding - DrMatrix[/sub]

2

Very interesting question, but my guess is that the answer is probably not exciting: the geochemistry of the Martian rocks may have great academic interest (like the Moon), but not much “practical” interest (like the Moon)–at least in terms of precious metals, gemstones, etc. Here’s my thinking:

First, what predicts what mineral phases will crystallize given the chemistry of the system? Thermodynamics (Phase Diagrams), which operates the same way on the Moon and Mars as it does on the Earth. For a fixed composition, what minerals crystallize depends (mostly) on the Temperature and Pressure of crystallization.

Second, what’s the chemistry of Mars like? Based on remote sensing, pathfinder, and meteorite data, it’s mostly mafic to intermediate volcanic rock (mostly basalt with some compositions evolved up to Fe-rich mafic andesite, nothing spectacular).

Third, what those data show are that: (1) the geology of Mars is–like the Moon and probably most asteroids–dominated by mafic (Fe and Mg rich, with <52 wt% SiO[sub]2[/sub]) rocks, and (2) these bodies have not really undergone extensive differentiation like the Earth has.

That last bit, chemical differentiation of the planet (which is broadly what I study), is why I think the answer is probably not an exciting one for future prospectors. Although the bulk composition of Mars may have gold abundances similar to Earth (a reasonable postulate), the geochemical differentiation processes responsible for concentrating those gold atoms into an economic deposit do not appear to have occurred. Why? Because Mars (again, like the Moon, Meteorites, etc.) lack “evolved” (felsic, e.g., granitic) rocks. (And, unsurprisingly, gold and silver deposits are mostly associated with these highly differentiated felsic rocks.) Gold, yes. Gold deposits, probably not.

That’s not to say that basalts are completely undifferentiated: what the Martian Prospector will find concentrated will be Fe-Mg minerals, and trace metals geochemically similar to these minerals (Co, Ni, Cr, Mn) crystallizing into mineral phases. I just doubt that those metals and minerals associated with more evolved rocks will be.

But I could be wrong.

Another thing to consider: an important differentiation process that operates primarily with very mafic (and very alkalic rocks) is liquid immiscibility. IF there is an extremely high concentration of sulfur in the system, then as the basaltic magma crystallizes, as separate, immiscible, sulfide liquid phase may form which would concentrate the chalcophile elements in the magma: Zn, Cu, Ag, Au, PGE, etc., from which would crystallzie metal-sulfide phases (sphalerite, cuprite, etc.) But again, you’d have to have a pretty good supply of gold in the magma system to begin with to make an economic deposit.

3

What about Mercury? From what I’ve heard, the further out in the solar system you go, the lighter the elements the planets are composed of. Mercury has the highest density of all the planets, and would seem themost likely to have valuable heavier elements. Would it be a valuable mining location, or would its small size and lack of volcanism mean the deposits would be too dilute to be worth extracting?

4

Very interesting question, but my guess is that the answer is probably not exciting: the geochemistry of the Martian rocks may have great academic interest (like the Moon), but not much “practical” interest (like the Moon)–at least in terms of precious metals, gemstones, etc. Here’s my thinking:

First, what predicts what mineral phases will crystallize given the chemistry of the system? Thermodynamics (Phase Diagrams), which operates the same way on the Moon and Mars as it does on the Earth. For a fixed composition, what minerals crystallize depends (mostly) on the Temperature and Pressure of crystallization.

Second, what’s the chemistry of Mars like? Based on remote sensing, pathfinder, and meteorite data, it’s mostly mafic to intermediate volcanic rock (mostly basalt with some compositions evolved up to Fe-rich mafic andesite, nothing spectacular).

Third, what those data show are that: (1) the geology of Mars is–like the Moon and probably most asteroids–dominated by mafic (Fe and Mg rich, with <52 wt% SiO[sub]2[/sub]) rocks, and (2) these bodies have not really undergone extensive differentiation like the Earth has.

That last bit, chemical differentiation of the planet (which is broadly what I study), is why I think the answer is probably not an exciting one for future prospectors. Although the bulk composition of Mars may have gold abundances similar to Earth (a reasonable postulate), the geochemical differentiation processes responsible for concentrating those gold atoms into an economic deposit do not appear to have occurred. Why? Because Mars (again, like the Moon, Meteorites, etc.) lack “evolved” (felsic, e.g., granitic) rocks. (And, unsurprisingly, gold and silver deposits are mostly associated with these highly differentiated felsic rocks.) Gold, yes. Gold deposits, probably not.

That’s not to say that basalts are completely undifferentiated: what the Martian Prospector will find concentrated will be Fe-Mg minerals, and trace metals geochemically similar to these minerals (Co, Ni, Cr, Mn) crystallizing into mineral phases. I just doubt that those metals and minerals associated with more evolved rocks will be.

But I could be wrong.

Another thing to consider: an important differentiation process that operates primarily with very mafic (and very alkalic rocks) is liquid immiscibility. IF there is an extremely high concentration of sulfur in the system, then as the basaltic magma crystallizes, as separate, immiscible, sulfide liquid phase may form which would concentrate the chalcophile elements in the magma: Zn, Cu, Ag, Au, PGE, etc., from which would crystallzie metal-sulfide phases (sphalerite, cuprite, etc.) But again, you’d have to have a pretty good supply of gold in the magma system to begin with to make an economic deposit.

5

Actually, this is not quite correct: its density is slightly less than Earth’s (5.42 g/cc vs. 5.52 g/cc) - see here for a table listing the densest major bodies in the solar system, with Earth at the top.

6

In A Man on the Moon it talks about Armstrong seeing something that looked like uncut diamonds or quartz crystals and mentions he intended to grab some, but doesn’t say if he did or what they might have been.

7

Here’s a blast from the past. I was searching for questions about Mars and it just so happens that I own that GURPS Mars book.

JasonG, I think you’re looking for the wrong mineral. The book says more about diamonds than it does about Mars:

I searched for “kimerlite Mars diamond” and found a few interesting articles, mostly by mineralogists and geologists and mostly over my head. But the simple version seems to be that diamonds are formed on Earth in high temperatures and high pressures, like subduction zones and volcanoes. Mars had active volcanoes at one point, so it might also have diamonds.

As one article at Rockhoundstation1 put it:

So maybe it’ll be a diamond rush instead of a gold rush. I agree that either would be a cool idea for a novel or a movie.

With two new Mars rovers and a new orbiter exploring the Red Planet since this question was posted, have there been any scientific discoveries that validate this theory, or that of other minerals or gems on Mars?

8

A recent article in – I think – American Scientist talked about biological influences on geology. Some types of rock are due to the influences of living things on the environment, directly or indirectly (one gross example being deposits of iron oxide that couldn’t even develop until plants started churning out free oxygen). I don’t think any of this affects gems, but it might affect what sorts of economically valuable rocks you might find.

My personal theory about what would be worthwhile mining in the solar system – helium from the gas giants. We’ll want it for work at ultra-low temperatures and bulk superconductivity. You find it floating to the top of oil deposits in impermeable rock layers, where it gathers as the end result of a lot of radioactive decay. But there’s only so much of it on earth, and it doesn’t combine chemically with anything. If you release it to the atmosphere it floats to the top, and eventually gets kicked off into space. Back in the 1950s and 1960s there was a movement to try to recover used helium in labs (one building i worked in had such a system, but it was long dormant), but that’s pretty much been dropped.

One day we may want all that helium.

9

I’ve heard that most other countries do in fact reclaim their helium. It’s only the US, with the world’s largest supply, that can afford to waste it.

10

Independently of this, as I was reading the thread, I too was thinking that Mars might make a better diamond field than gold because of its geology. But then I remember that, supposedly, diamonds are plentiful on Earth, just expensive due to the cartel nature and manufactured demand.

So if there were Martian diamonds, they certainly would be pretty valuable – for their exotic value (and if the market isn’t flooded with them all at once.)

11

I read it too a couple months ago but I don’t think it was AS.

12

I doubt any scarcity and novelty is sufficient to overcome the multiple orders of magnitude of cost increase from mining something on Mars.

13

There’s an SF novella by Arthur C. Clarke about an astronaut who discovers a very large diamond on the moon (possibly the biggest ever known), but is almost immediately deflated and his financial prospects are dashed due to the almost simultaneous discovery of a cheap method for synthetic diamond creation, to the point where the astronaut considers just throwing the diamond away.

14

If you want mineral treasure, look to the Asteroid Belt.

Easy access, easy shipping (no gravity well to overcome), & if the Belt is the ruins of a lost planet, high density deposits of metals-rich core material.

15

Surely mars would be a good place to find iron ore (that’s what makes it red, after all?).

16

As it happens, the late Kage Baker’s recent novel The Empress of Mars is set around an idea like this (although it is an alternate history).

17

Here on Earth, limestone is quite common. However, a planet without large, old oceans in which sea life that used calcium carbonate as part of its structure probably wouldn’t have limestone.

We’ve also got amber, fossilized tree resin. A planet which didn’t have ancient plant life wouldn’t have amber.

Those are both examples of stones which we think of as common, but which people from other planets might want simply due to their rarity. We’re pretty certain Mars had life at one point (it might even have it now, if only primitive lifeforms). Therefore, it follows that Mars might have a byproduct of ancient life which we’ve never seen before and which might be considered valuable here.

Maybe some sort of Martian amber? I can easily imagine Martian amber selling for a lot here on Earth. Especially if it had some sort of unique property, like the optics of opal.

18

I thought amber was formed from fossilised tree sap?

19

Iron?

You wanna haul iron, up out of Mars’ gravity well, then boost it across to Earth…at expense?

Why not mine the nickel-iron asteroids?

20

From the Wikipediaentry: “Amber (or, technically, resinite) is fossilized tree resin (not sap), which has been appreciated for its color and natural beauty since Neolithic times.”