Water Isolated for Over a Billion Years Found Under Ontario 207
ananyo writes "Scientists working 2.4 kilometers below Earth's surface in a Canadian mine have tapped a source of water that has remained isolated for at least a billion years. The researchers say they do not yet know whether anything has been living in it all this time, but the water contains high levels of methane and hydrogen — the right stuff to support life. Micrometer-scale pockets in minerals billions of years old can hold water that was trapped during the minerals' formation. But no source of free-flowing water passing through interconnected cracks or pores in Earth's crust has previously been shown to have stayed isolated for more than tens of millions of years (paper abstract)."
Re:Nice try.... (Score:5, Informative)
Where they there to see it trapped? Then how do they know!?
I see you're keeping slashdot's tradition of not reading TFA. Here's what the very short article says about that:
To date the water, the team used three lines of evidence, all based on the relative abundances of various isotopes of noble gases present in the water. The authors determined that the fluid could not have contacted Earth's atmosphere — and so been at the planet's surface — for at least 1 billion years, and possibly for as long as 2.64 billion years, not long after the rocks it flows through formed.
Re:Nice try.... (Score:5, Informative)
They looked at the decay of radioactive atoms found in the water and calculated that it had been bottled up for a long time — at least 1.5 billion years
They found that the water is rich in dissolved gases like hydrogen, methane and different forms of noble gases such as helium, neon, argon and xenon.
They say there is as much hydrogen in the water as around hydrothermal vents in the deep ocean.
Re:Nice try.... (Score:5, Informative)
I'm pretty sure GPP is making fun of Ken Ham's thought-stopping advice to his followers [google.com], which is supposed to immediately make "evolutionists" stop dead in their tracks, fall down on their knees, pray for forgiveness, and embrace the obvious Truth. Or something like that.
Re:Nice try.... (Score:4, Informative)
You might think that comment was "skeptical" or that it demonstrates your "critical thinking" but really, it was just plain ignorant. Based on this comment, one might reasonably assume you fall in with the kind of douchetards that yell out "42! Haha!" every time a mathematical discussion takes place.
To answer your question, you might start by reading the article. It talks about isotopes and geochemistry.
Then you could do some reading at the library to find out more about isotopes and geochemistry, and why these things are interesting and important. If you want to go further, you could take an undergraduate degree in geology, where you will learn all kinds of strange and wonderful things about the Earth, and how we can know about things that occurred billions of years ago.
Re:It is time (Score:5, Informative)
Re:Measurement exactly? (Score:5, Informative)
It's technical [nature.com].
Okay, basically there are a bunch of noble gas isotopes (He, Ne, Ar, and Xe). Some of these are generated by radioactive decay of isotopes within the Earth, and some are not, having been generated by nuclear fusion in the stars that eventually went supernova and were subsequently swept up by gravity to form the solar system. Over geological time, the ratio between these essentially "fixed"/inherited/initial isotopic amounts in the Earth and the newer "radiogenic" isotopes changes. This can be measured in the present-day atmosphere, which amounts to a kind of time-and-geographically-averaged sample of what is currently outgassing from the entire Earth. By contrast, if you isolate/trap some of these gasses in minerals or fractures and fail to mix them with newer radiogenic sources over time, then they're going to preserve the isotopic ratios from the time that they first got trapped and last interacted with the isotopic mixture that was slowly outgassing from the Earth at the time. The change in the isotopic ratios are something you can pretty easily project backwards if you know the average composition of the Earth, which we do (based on some types of meteorites that fall here and that represent undifferentiated leftovers from the formation of the solar system). Measure the isotopic composition of the fluid sample, look along that line describing how the isotopic ratios have changed over Earth history due to known rates of decay and concentrations, and you can estimate the corresponding age of the sample. The focus in this paper is Xe isotopes, but they have data for Ne, He, and Ar as well.
This is *not* a traditional radiometric dating method, which ordinarily uses minerals, not fluids. Furthermore, for minerals it's usually fairly easy to look at the mineralogy of a sample at a microscopic scale and assess whether it is likely the system has remained closed (isolated from isotopic exchange with its surroundings) before analyzing the sample. For example, if a feldspar grain containing K has been partly altered into micas, this shows up clearly and would indicate that any result from the K/Ar method wouldn't reliably give you the age of the feldspar.
The method with the fluids is almost the reverse. If the system had not remained closed/isolated (the normal expectation), then the multiple isotopic systems shouldn't yield a similar age. They do (within measurement uncertainties), implying the bold interpretation that the fluids have indeed been isolated for that long.
An additional wrinkle is that they are analyzing fluids both from fractures and from what are called "fluid inclusions [wikipedia.org]", which are microscopic (typically 100 microns or less) pockets of fluid trapped within individual mineral grains (trapping fluids at the time the grain crystallized). Being able to compare those two types allows some additional assessment of mixing between fluids of different generations and origins (e.g., shallow crustal versus deep mantle fluids) and a host of other subtleties. Additional information is also provided by comparing to previously-published fluid analyses from other locations (South Africa and Australia) that are already known to be about the same host rock age. In any case, finding that fluid inclusions have an "ancient" isotopic signature isn't that big a deal (it means the minerals haven't been recrystallized by processes since then). The big surprise is finding that even the larger fractures seem to show the same signature rather than that of water with more modern isotopic compositions. That's amazing. And deserves some skepticism, which the authors try to address by looking at the other isotopic systems.
That's about as far as I can get with only a few paragraphs of explanation. It only scratches the surface, but I hope it helps.
Re:It is time (Score:5, Informative)
While no, you're not going to spawn a black hole at LHC (the laws of nature are rather resilient against that, and the entire Earth hasn't enough mass to make one), there are some good, hard uses for dystopian fantasy-type warnings.
Since this thread is about dispelling common false beliefs, I feel like I should pitch in here: general relativity sets no minimum for the mass of a black hole! If you get energy density high enough, you get a black hole. Quantum mechanics does suggest a likely minimum energy (though until GR and Quantum are reconciled, it's guesswork), but that minimum is still pretty low.
The right question to ask is "can the LHC create a black hole which is a threat to anything?" and the answer is "no, black holes that small just don't last long enough to grow larger (if one was somehow created in the first place)".