Origin of massive methane reservoir identified

Posted: August 21, 2019 by oldbrew in Geology, research
Tags: , , ,

Natural gas flare {credit: Wikipedia]


As we already knew from elsewhere in the solar system, fossils are not essential for the production of methane aka natural gas. Only two ingredients are needed, one being water, as explained below.

New research from Woods Hole Oceanographic Institution (WHOI) published Aug. 19, 2019, in the Proceedings of the National Academy of Science provides evidence of the formation and abundance of abiotic methane—methane formed by chemical reactions that don’t involve organic matter—on Earth and shows how the gases could have a similar origin on other planets and moons, even those no longer home to liquid water.

Researchers had long noticed methane released from deep-sea vents, says Phys.org. But while the gas is plentiful in the atmosphere where it’s produced by living things, the source of methane at the seafloor was a mystery.

“Identifying an abiotic source of deep-sea methane has been a problem that we’ve been wrestling with for many years,” says Jeffrey Seewald a senior scientist at WHOI who studies geochemistry in hydrothermal systems and is one of the study’s authors.

Of 160 rock samples analyzed from across the world’s oceans, almost all contained pockets of methane. These oceanic deposits make up a reservoir exceeding the amount of methane in Earth’s atmosphere before industrialization, estimates Frieder Klein, a marine geologist at WHOI and lead author of the study.

“We were totally surprised to find this massive pool of abiotic methane in the oceanic crust and mantle,” Klein says.

The scientists analyzed rocks using Raman spectroscopy, a laser-based microscope that allows them to identify fluids and minerals in a thin slice of rock.

Nearly every sample contained an assemblage of minerals and gases that form when seawater, moving through the deep oceanic crust, is trapped in magma-hot olivine. As the mineral cools, the water trapped inside undergoes a chemical reaction, a process called serpentinization that forms hydrogen and methane.

The authors demonstrate that in otherwise inhospitable environments, just two ingredients—water and olivine—can form methane.

“Here’s a source of chemical energy that’s being created by geology,” says Seewald.

Full report here.
– – –
Abstract of the paper:

Our findings highlight the ubiquitous occurrence of methane (CH4)-rich fluid inclusions in olivine-bearing rocks that, collectively, may constitute one of the largest reservoirs of abiotic CH4 on Earth. Because serpentinization in olivine-hosted fluid inclusions takes place in isolation from the surrounding rock, hydrogen (H2) and CH4 can form in any rock type containing olivine that hosts aqueous fluid inclusions, including those that do not undergo serpentinization on a macroscopic scale. Serpentinization and associated CH4 formation within olivine-hosted fluid inclusions has likely supplied microbial ecosystems with abiotic CH4 throughout most of Earth’s history and may be a source of H2 and CH4 on other planetary bodies in our solar system, even those where liquid water is no longer present.

Comments
  1. pochas94 says:

    I was left wondering “Where does the carbon come from?”

  2. gbaikie says:

    Carbon comes from the seawater??
    bicarbonates and CO2 in sea water.

  3. oldbrew says:

    Wikipedia on serpentinite…

    Carbonates and sulfates are subsequently reduced by hydrogen and form methane and hydrogen sulfide.
    https://en.wikipedia.org/wiki/Serpentinite#Formation_and_petrology

    In the presence of carbon dioxide, however, serpentinitization may form either magnesite (MgCO3) or generate methane (CH4). It is thought that some hydrocarbon gases may be produced by serpentinite reactions within the oceanic crust.
    https://en.wikipedia.org/wiki/Serpentinite#Serpentinite_reactions

  4. pochas94 says:

    OIC:
    18 Mg2SiO4 + 6 Fe2SiO4 + 26 H2O + CO2 → 12 Mg3Si2O5(OH)4 + 4 Fe3O4 + CH4
    thnx

  5. chickenhawk says:

    Gaia is great and wonderful. We bow down to your wisdom.

    Now Greenies can finally come on board with some methane love.
    I think I heard it once on the blues station, maybe Howlin’ Wolf singing, gimme some of that methane love baby…

  6. oldbrew says:

    pochas 94 says: August 21, 2019 at 12:51 pm

    Yes, that’s the ‘balanced form’ (Reaction 2a’).
    Olivine is (Fe,Mg)2SiO4 (Reaction 2a).

    See: https://en.wikipedia.org/wiki/Serpentinite#Serpentinite_reactions
    – – –
    AUGUST 21, 2019
    A step closer to solving the methane mystery on Mars

    “The methane on Mars has other possible sources, such as water-rock reactions or decomposing materials containing methane.”

    Last year, scientists learned that methane concentrations changed over the course of the seasons with a repeatable annual cycle.

    “This most recent work suggests that the methane concentration changes over the course of each day*,” Dr. Moores said.

    https://phys.org/news/2019-08-closer-methane-mystery-mars.html

    *Each Martian day.

  7. Curious George says:

    Why do scientists attempt to explain the “origin of methane” as coming from chemical reactions between much more complex compounds? Can’t there be a “primordial” methane?

  8. stpaulchuck says:

    the Russians published papers years ago showing abiotic generation of methane AND OIL. I don’t have the reference at hand. At the time the arbiters of “what is right” peed all over them for their ‘crazy’ ideas. Hmmm, maybe not so crazy after all.

  9. oldbrew says:

    Methane clathrate

    The nominal methane clathrate hydrate composition is (CH4)4(H2O)23, or 1 mole of methane for every 5.75 moles of water, corresponding to 13.4% methane by mass, although the actual composition is dependent on how many methane molecules fit into the various cage structures of the water lattice.

    https://en.wikipedia.org/wiki/Methane_clathrate#Structure_and_composition
    – – –
    Some estimates put the reserves of energy found in methane hydrates exceeding that of all other fossil fuels put together.

    https://www.petropedia.com/2/9808/oil/biogenic-and-thermogenic-gases-how-significant-they-are-in-energy-space

    Or ‘so-called fossil fuels’ 🙂

  10. pochas94 says:

    So, if you have carbonates and some water around with iron (olivine) for a catalyst you can make all sorts of goodies. The Fischer-Tropf process operates under similar conditions with an iron (or cobalt) catalyst to produce petroleum. We are always feeding carbonates to the mantle by continental plate subduction. Could it be that petroleum/natural gas formation is a renewable process?

  11. Gamecock says:

    “The Russians published papers years ago showing abiotic generation of methane AND OIL.”

    Chirality falsifies abiotic oil. It is a non-subject. Dead on arrival.

    Abiotic generation of methane is quite likely. Organisms processing abiotic methane producing oil is a very possible source of oil.

  12. BoyfromTottenham says:

    Great science. It reverses the H L Mencken proposition that ‘for every complex problem there is an answer that is clear, simple and wrong’.

  13. David A says:

    Gamecock ? adjective Chemistry.
    (of a molecule) not superimposable on its mirror image.
    Please explain.

  14. David A says:

    A general ? please.
    Dies anyone have a link to list of prominent CAGW skeptics such as Richard Lindzen …?

    [reply] they’re all called d****** here 😂😂
    https://www.desmogblog.com/global-warming-denier-database

  15. David A says:

    Does, not dies
    Sheesh

  16. Gamecock says:

    “Please explain.”

    No. It is BASIC organic chemistry.

  17. pochas94 says:

    It is well known that organisms feed on petroleum and hence would contribute to the “chirality” of the substrate they feed on, however it was originally formed. There is also a political component here. If petroleum is renewable one must look elsewhere to justify massive social engineering projects. Abiotic oil is still an open question, if we can ever get past the politics.

  18. Gamecock says:

    The U.S. uses 19,700,000 barrels a day of non-abiotic oil.

    Could abiotic oil exist? Yes. Does it matter? No. Maybe the Russians found some; maybe they didn’t. It is completely irrelevant.

    The search should be for the organism(s) that can convert methane into longer chain hydrocarbons.

  19. E.M.Smith says:

    Chirality (left vs right handed molecules) is not exclusively a property of living chemistry. Inorganic chemistry can produce chiral results as well. Not as common, but does happen.

    It is quite clear that F.T. reactions can happen in deep hot rocks. Pretty much anything with hot enough carbonates starts to react with a large variety of metal and non-metal catalysts. (Iron, Cobalt, Nickle, zeolite rocks, etc. etc.). Largely producing a-chiral linear chain products. Alkanes and such.

    It is also known that rocks are just full of all sorts of bacteria that just love to eat alkanes.

    So the abiotic process is known to make stuff the bugs like to eat. The bugs are all over the place in rocks. They make chiral compounds. So is it any surprise that natural oil is largely non-chiral compounds with a bunch of junk in them some of which is chiral?

    The chirality argument, at best, can argue for biological contamination of abiotic oil. It can not prove the base stock of non-chiral FT products was biological in origin..

    FWIW, many big known oil deposits, like the North Sea, are clearly biological in origin. Not dinosaurs, but algae. Ancient warm seas with anoxic lower levels.made megatons of algae (that can be up to 50% biological oils) that die, sink, and make deposits. Covered in silt / erosion products and cooked a bit, you get a very nice crude oil. We can do the same thing with algae from farms today.

    IMHO, showing that a LOT of oil is clearly from biological sources is an important point and more effective than saying “It is IMPOSSIBLE to have abiotic oil” when we absolutely know we can make abiotic oil in the lab using F.T. methods (and others) from natural materials.

    What places like North Sea do not explain is oil deposits under miles of hard rock…nor the way that the deeper the oil, the less evidence of biological stuff in it. So I would speculate that it is a complex mix. Nature making the methane and then SOME of it polymerizing (as all alkane like things tend to do) under high heat, pressure, and catalytic rocks, but a lot also being made via plants / algae turning CO2 to polymers, dying, and being buried.

    It isn’t an “either or”, it is a “both”. But nobody can say how much of each as it’s all mixed up in a mess over a few billion years. But we KNOW both sets of reactions happen. Life and F.T.

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