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posted by chromas on Thursday July 02 2020, @04:30PM   Printer-friendly
from the where-the-mother-lode-gives-birth? dept.

Geologists identify deep-earth structures that may signal hidden metal lodes

If the world is to maintain a sustainable economy and fend off the worst effects of climate change, at least one industry will soon have to ramp up dramatically: the mining of metals needed to create a vast infrastructure for renewable power generation, storage, transmission and usage. The problem is, demand for such metals is likely to far outstrip currently both known deposits and the existing technology used to find more ore bodies.

Now, in a new study, scientists have discovered previously unrecognized structural lines 100 miles or more down in the earth that appear to signal the locations of giant deposits of copper, lead, zinc and other vital metals lying close enough to the surface to be mined, but too far down to be found using current exploration methods. The discovery could greatly narrow down search areas, and reduce the footprint of future mines, the authors say. The study appears this week in the journal Nature Geoscience.

[...] The study found that 85 percent of all known base-metal deposits hosted in sediments-and 100 percent of all "giant" deposits (those holding more than 10 million tons of metal)-lie above deeply buried lines girdling the planet that mark the edges of ancient continents. Specifically, the deposits lie along boundaries where the earth's lithosphere-the rigid outermost cladding of the planet, comprising the crust and upper mantle-thins out to about 170 kilometers below the surface.

Up to now, all such deposits have been found pretty much at the surface, and their locations have seemed to be somewhat random. Most discoveries have been made basically by geologists combing the ground and whacking at rocks with hammers. Geophysical exploration methods using gravity and other parameters to find buried ore bodies have entered in recent decades, but the results have been underwhelming. The new study presents geologists with a new, high-tech treasure map telling them where to look.

Journal Reference:
Mark J. Hoggard, Karol Czarnota, Fred D. Richards, et al. Global distribution of sediment-hosted metals controlled by craton edge stability, Nature Geoscience (DOI: 10.1038/s41561-020-0593-2)

-- submitted from IRC


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  • (Score: 0) by Anonymous Coward on Friday July 03 2020, @02:22AM (13 children)

    by Anonymous Coward on Friday July 03 2020, @02:22AM (#1015634)

    It would be truly idiotic to attempt such a thing. If you were successful, you'd doom the planet to extinction. If you fail, huge volcano.

  • (Score: 1) by khallow on Friday July 03 2020, @12:59PM (12 children)

    by khallow (3766) Subscriber Badge on Friday July 03 2020, @12:59PM (#1015732) Journal
    The easier way would be for Von Neumann machines to take the Earth apart from the surface on down. It'd get easier as more mass is orbited. It'd take a lot of licks to get to the center of this pop, but a Von Neumann swarm has a lot of tongues.

    If you were successful, you'd doom the planet to extinction.

    And your point is? I don't see even the slightest need to mine the Earth's core today. But in half a billion to billion years, the Earth is doomed anyway. Might as well make something useful of it when that time comes.

    • (Score: 2) by Immerman on Friday July 03 2020, @02:19PM (11 children)

      by Immerman (3985) on Friday July 03 2020, @02:19PM (#1015758)

      >But in half a billion to billion years, the Earth is doomed anyway.

      Hardly. It'd be far easier to move the Earth than mine it away - we even have a convenient gravitational tugboat already handy in the moon, we just need to install some engines and we can tow the Earth around to keep it in a nice temperate orbit around the aging sun and eventual expanding red giant. Assuming some sort of reasonably efficient mass conversion we could even install massive lights on the near surface of the moon to simulate the sun and tow the Earth through interstellar space to a new star - or just soar across the galaxy indefinitely, occasionally nabbing a new moon as we pass a star system to keep the system powered.

      As interstellar world-ships go, an actual planet is hard to beat, so long as you're not in a hurry to get anywhere.

      • (Score: 1) by khallow on Sunday July 05 2020, @03:22AM (10 children)

        by khallow (3766) Subscriber Badge on Sunday July 05 2020, @03:22AM (#1016364) Journal

        As interstellar world-ships go, an actual planet is hard to beat

        Except by a bunch of smaller world-ships with say, a billion or more times the surface area of Earth.

        • (Score: 2) by Immerman on Sunday July 05 2020, @02:27PM (9 children)

          by Immerman (3985) on Sunday July 05 2020, @02:27PM (#1016511)

          So long as you're okay with all the vulnerabilities of flying in a massive tin can. Not that a planet is completely invulnerable - but it has a very different set of vulnerabilities, and in general is far more robust - especially if you can control the brightness of the "sun" to compensate for environmental fluctuations.

          Don't get me wrong - I'd love to see humanity living in clouds of O'Neill cylinders with vast floating microgravity cities down their cores... but artificial habitats just aren't robust enough to allow chaos to run free. And while there are many benefits to a controlled environment, I dearly hope we never lose our appreciation for the power and bounty of nature unchained - and nature can't truly exist in the limited confines of a controlled environment.

          It's not like there's any shortage of raw materials floating around to make artificial habitats - including all the other planets we don't decide to terraform. But I strongly hope that the oasis that gave us birth will maintain a certain sentimental value.

          If nothing else, if allowed to lie relatively fallow the rich native biodiversity could provide a steady stream of new intelligent species to join us, assuming we're not so xenophobic as to want our own species to be the only intelligent life in our corner of the galaxy. How many million-year epochs do you suppose it takes on average before a new technological civilization arises? Ours is the only one we know of so far (assuming we include all our hominid cousin species), but it's only been a few hundred since the Cambrian Explosion gave birth to a huge diversity of complex life - and there'll be millions more to come before the red dwarves start burning out.

          • (Score: 1) by khallow on Sunday July 05 2020, @11:37PM (8 children)

            by khallow (3766) Subscriber Badge on Sunday July 05 2020, @11:37PM (#1016714) Journal

            So long as you're okay with all the vulnerabilities of flying in a massive tin can.

            Such as massive redundancy?

            • (Score: 3, Interesting) by Immerman on Monday July 06 2020, @01:06PM (7 children)

              by Immerman (3985) on Monday July 06 2020, @01:06PM (#1016994)

              Compared to a planet? Not hardly. Not on an individual basis anyway.

              It's the difference between spreading your eggs across a multitude of tiny fragile baskets, and putting them all in one heavily armored nigh-indestructible bunker.

              If your primary concern is that some of the eggs survive (aka the survival of the species), lots of fragile baskets may be a better bet - though given the scale of astronomical disasters there's an awful lot of things (like a nearby supernova or other such high-energy event) that could easily kill everything in all the baskets, while only killing the facing surface of a planet.

              On the other hand, if your primary concern is the survival of a specific handful of eggs (yourself and your family), then putting them in the bunker radically increases their safety.

              • (Score: 1) by khallow on Tuesday July 07 2020, @12:36PM (6 children)

                by khallow (3766) Subscriber Badge on Tuesday July 07 2020, @12:36PM (#1017581) Journal

                Compared to a planet? Not hardly. Not on an individual basis anyway.

                Yes, compared to a planet. And how could I be thinking of redundancy on an individual basis?

                If your primary concern is that some of the eggs survive (aka the survival of the species), lots of fragile baskets may be a better bet - though given the scale of astronomical disasters there's an awful lot of things (like a nearby supernova or other such high-energy event) that could easily kill everything in all the baskets, while only killing the facing surface of a planet.

                You don't need the full thickness of a planet to shield against such high energy events. And one of the advantages of lots of slightly more fragile baskets is that you can spread the baskets around. Some baskets might end up near the supernova. Others won't. And if you have enough warning, you can move those smaller craft out of the way quicker than you could move a planet. For example, given 10,000 years warning, you could move a significant distance away, while the planet just has to tough it out.

                • (Score: 2) by Immerman on Tuesday July 07 2020, @02:36PM (5 children)

                  by Immerman (3985) on Tuesday July 07 2020, @02:36PM (#1017655)

                  >And how could I be thinking of redundancy on an individual basis?
                  The Earth is massively redundant as an individual system, because every ecological component is massively redundant.

                  >You don't need the full thickness of a planet to shield against such high energy events.
                  True, but you need a LOT more material than you would need to shield against normal background radiation in space, and it's extremely unlikely you'd apply that to all those artificial habitats since it's a massive disadvantage in all other circumstances.

                  >And one of the advantages of lots of slightly more fragile baskets is that you can spread the baskets around. Some baskets might end up near the supernova. Others won't. And if you have enough warning, you can move those smaller craft out of the way quicker than you could move a planet. For example, given 10,000 years warning, you could move a significant distance away, while the planet just has to tough it out.

                  There's no getting out of the way of a supernova, not within a solar system. Either you're got enough light-years of distance between you, or you don't. And the Earth is no more difficult to move than an equivalent mass of artificial habitats. And you're not going to get a whole lot of warning, since the radiation wave travels at light speed. With enough advancements in stellar physics we might be able to accurately predict the collapse 10,000 years out, but it seems a stretch since all the really interesting changes are hidden beneath thousands of miles of stellar material.

                  Assuming you do get millenia, or even decades of warning, the habitats could either try to flee, or just pile on a bunch more radiation shielding and hope for the best (probably far more reliable and cost-effective). Meanwhile the Earth will in fact tough it out - killing most life on one side of the planet is rough but easily repopulated within a few decades, especially if there's some human intervention. Assuming most human habitats were self-contained underground vaults (every bit as comfy as a space habitat, with far more radiation and impact shielding) we'd barely even notice except when visiting the parks on the surface.

                  • (Score: 1) by khallow on Tuesday July 07 2020, @11:29PM (4 children)

                    by khallow (3766) Subscriber Badge on Tuesday July 07 2020, @11:29PM (#1017919) Journal

                    The Earth is massively redundant as an individual system, because every ecological component is massively redundant.

                    So if I wipe out all life on Earth, some ecological component(s) will somehow do something to reverse that? I can do massively redundant ecological components with that other stuff too.

                    • (Score: 2) by Immerman on Wednesday July 08 2020, @01:35PM (3 children)

                      by Immerman (3985) on Wednesday July 08 2020, @01:35PM (#1018186)

                      Obviously not. But things are so massively redundant that you'll find it virtually impossible to wipe out all life on Earth, while wiping out all life in an orbital habitat would be trivial. And there's several common cosmic disasters that could wipe out all life in ALL such habitats in the solar system, unless they were ridiculously overbuilt to defend against such dangers that are unlikely to occur within any given million-year window. Disasters that the Earth *has* been repeatedly subjected to without jeopardizing the long-term survival of the life here.

                      • (Score: 1) by khallow on Sunday July 12 2020, @05:20AM (2 children)

                        by khallow (3766) Subscriber Badge on Sunday July 12 2020, @05:20AM (#1019737) Journal

                        while wiping out all life in an orbital habitat would be trivial.

                        What happens when the orbital habitat is bigger in land area than Earth, better shielded, and easier to move around because it's orders of magnitude lighter? I'm not saying this is the ideal way to do orbital habitats, but you have a lot of options with them and how they're configured that you don't have with a planet.

                        • (Score: 2) by Immerman on Sunday July 12 2020, @03:06PM

                          by Immerman (3985) on Sunday July 12 2020, @03:06PM (#1019849)

                          >What happens when the orbital habitat is bigger in land area than Earth...

                          Then we've basically already ascended to demigodhood, can easily mine the gas giants, and probably even mine the sun directly for mass that we can transmute into whatever elements we want. So what's the motive for pulverizing Earth?

                          One thing to keep in mind is that the asteroid belt already has enough material to build enough orbital habitats to support a thousand times the current population - and adding the other rocky planets would increase that by a few thousandfold more.

                          Using just the asteroids we'll have a thousand times as many Einsteins, Mozarts, etc., and the pace of social and technological change is likely to be so high that the world (and what is possible) will be completely unrecognizable within a single generation.

                          Meanwhile, if we assume 4 kids per woman to double the population every generation, it's going to take ten or fifteen generations to fill the habitats made from the dead rocky planets, with the number of active geniuses increasing all the time. I feel safe in assuming that we'd have advanced to mining the gas giants before kicking everyone off Earth began looking remotely appealing. And by the time we're done with the gas giants,mining the sun itself will probably be within easy reach. I suspect Earth will be spared by simple virtue of there being enough more attractive stepping stones that we'll blow right past having much industrial use for it

                          There's a counterpoint as well though that I think may stop us from ever reaching such massive populations in the first place - social changes cause stress, which tends to reduce birth rates. Since larger populations cause faster social change, it seems likely that at some point the stress from the pace of social change will drive population growth below zero and stabilize the population. And frankly, it seems very possible we're approaching that level already.

                        • (Score: 2) by Immerman on Sunday July 12 2020, @03:33PM

                          by Immerman (3985) on Sunday July 12 2020, @03:33PM (#1019861)

                          Oh, and another thought on artificial habitats versus planets: Planets are held together by gravity - created by entropy, while artificial habitats will have to fight entropy constantly, mechanically holding themselves together against the pressure and centrifugal forces they contain. That means you need to constantly inspect and repair them, ideally through some form of integrated nano- or bio-technology, but for the foreseeable future you'd probably have to either overbuild the things enough that every single structural component can be replaced "live", or plan on retiring them periodically before catastrophic failure inevitably occurs. (I'd love to believe the first would be the norm, but we seem to have a real aversion to paying a substantial preium today for something that will benefit our grandkids.)