Deep-earth carbon offers clues on origin of life on Earth

A composite image of the Western hemisphere of the Earth. Credit: NASA

New findings by a Johns Hopkins University-led team reveal long unknown details about carbon deep beneath the Earth's surface and suggest ways this subterranean carbon might have influenced the history of life on the planet.

The team also developed a new, related theory about how diamonds form in the Earth's mantle.

For decades scientists have had little understanding of how carbon behaved deep below the Earth's surface even as they learned more and more about the element's vital role at the planet's crust. Using a model created by Johns Hopkins geochemist Dimitri Sverjensky, he, Vincenzo Stagno of the Carnegie Institution of Washington and Fang Huang, a Johns Hopkins graduate student, have become the first to calculate how much carbon and what types exist in fluids at 100 miles below the Earth's surface at temperatures up to 2,100 degrees F.

In an article published this week in the journal Nature Geoscience, Sverjensky and his team demonstrate that in addition to the carbon dioxide and methane already documented deep in subduction zones, there exists a rich variety of species that could spark the formation of diamonds and perhaps even become food for microbial life.

"It is a very exciting possibility that these deep fluids might transport building blocks for life into the shallow Earth," said Sverjensky, a professor in the Department of Earth and Planetary Sciences. "This may be a key to the origin of life itself."

Sverjensky's theoretical model, called the Deep Earth Water model, allowed the team to determine the chemical makeup of fluids in the Earth's mantle, expelled from descending tectonic plates. Some of the fluids, those in equilibrium with mantle peridotite minerals, contained the expected carbon dioxide and methane. But others, those in equilibrium with diamonds and eclogitic minerals, contained dissolved organic carbon species including a vinegar-like acetic acid.

These high concentrations of dissolved carbon species, previously unknown at great depth in the Earth, suggest they are helping to ferry large amounts of carbon from the subduction zone into the overlying mantle wedge where they are likely to alter the mantle and affect the cycling of elements back into the Earth's atmosphere.

The team also suggested that these mantle fluids with dissolved organic species could be creating diamonds in a previously unknown way. Scientists have long believed diamond formation resulted through chemical reactions starting with either or methane. The organic species offer a range of different starting materials, and an entirely new take on the creation of the gemstones.

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Computer models show how deep carbon could return to Earth's surface

Journal information: Nature Geoscience

Citation: Deep-earth carbon offers clues on origin of life on Earth (2014, November 20) retrieved 24 August 2019 from
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Nov 20, 2014
Origin of life? Give me a break! What nonsense!
Why do evolutionists always try to tie their otherwise scientific research to an unfounded theory? Probably because their atheist worldview is domineering.

Why does a creationist troll comment on a science site?

Nov 20, 2014
Unfounded theory, wtf?

I was just going to mention that most of the carbon in the mantle and crust (between 60-100 BAR) started off in the atmosphere as CO2.

That is all.

Nov 20, 2014
Origin of life? Give me a break! What nonsense!

Are you saying things have no origin?
My shoe came from a cow. Dirt came from a rock. Biology comes from chemistry. A star comes from gas. A Cheetah runs fast because he comes from savannah.
And a looney guy named Verkle comes from an American demographic statistic, and the rest of the world comes to tell him why he's wrong.

Nov 20, 2014
Meanwhile, what's an "atheist worldview?"

You mean we don't believe fairy tales about an invisible super magic sky daddy written by drunken stone age sheep herders and put in a book called the Babble?

Nov 21, 2014
I was just going to mention that most of the carbon in the mantle and crust (between 60-100 BAR) started off in the atmosphere as CO2.
Ummm, no, not really.

Maybe in the crust, it might have come from the Late Heavy Bombardment. But carbon in the mantle is mostly primordial. This is obvious; if you drove a car to the top of the atmosphere, you'd be there in an hour; to drive one to the Earth's core would take a week.

The primordial element concentration has carbon as the fourth most common element, after hydrogen, helium, and oxygen, in the Milky Way. Because Earth is a rocky planet, however, these abundances do not reflect the abundance on Earth. Oxygen is the most common atom on Earth; a bunch of metals, hydrogen, and sulfur precede carbon in abundance, but it still makes up a million six hundred thousand atoms out of every billion, so it's fairly common throughout the Earth.

Your assertion is silly. You should know better, since you're a geologist.

Nov 21, 2014
TCIF (Thank the Calendar It's Friday)! So bloviating on this: Objects have an origin, while processes (such as general relativity) does not necessarily have to.

But we know they emerge out of nature in both cases, biology is a good demonstration since its laws of evolutionary mechanisms (variation in populations, natural selection) did not exist until some ways after the Hot Big Bang. Same goes for the standard particles, since first inflation and later the Hot Big Bang were much more energetic. So laws and the objects they act on are always and exclusively seen to arise naturally, putting creationism in the waste bin of bad ideas.

Nov 21, 2014
Furthermore, and related to the article, we know that life emerged out of geophysical systems.

Gene centered evolution has a hereditary memory which is what that vital core of evolution, population genetics, concerns and what people mostly connect with evolution. But the process has also a surrounding and diffuse environmental memory.

A gene, typically only "knows" (has evolved as a function) how to produce a protein. By itself it can't reproduce, it has to have the other genes that it sees as part of the environment. But again it isn't enough with the genome, it needs the environment of an already existing cellular machinery to replace parts in and reproduce with. Even the cell isn't enough, it needs a familiar enough environment (water, nutrients) not too different from what earlier generations lived in in order for the genes to eventually reproduce.

Hence we have an associated environmental memory that is dragged along by surviving life in various ways.

Nov 21, 2014

And this memory records still today the phylogenetic traits of the geophysical systems life emerged in.

Those traits have been identified as:
- Hadean ocean: element ratios of ocean and solute crust, temperature range for early life (RNA temperature range, heat shock proteins), carbon [dioxide] based anabolism, FeII metabolic chains.

- Alkaline hydrothermal vent: cellular compartments; membranes; pH differential size; pH differential direction; redox potential metabolic range; electron bifurcating metal atoms metabolic engines.

A binomial test of these 10+ traits vs the 5+ traits of "soup" theories (oceanic elements, temperature range, nucleotides, lipids, bubbles)* gives that geophysical emergence should be able to reject the competition as nonviable. (E.g. the difference is larger than 3 sigma vs the best null hypothesis of heat- and light-driven "soup".)

* Or vs the 0 shared traits of creationism accidental random emergence of modern species.

Nov 21, 2014
Earth-based abiogenesis is necessarily conjecture and theory at this point in our research, but I have difficulty believing that the "shallow Earth" is dynamic enough to create an environment which supports the chemistries, selective pressures, and the quantities of reactions and interactions necessary. Particularly, in the context of organic molecules being present on objects which bombarded the Earth in significant quantities in the 1BN+ years between formation and appearance of life.

Nov 21, 2014
You mean it's conjecture and hypothesis, right, cjn? If it were theory it would mean we can do it in the lab. And we're not quite there yet.

Nov 23, 2014
cjs, Schneib: You are both wrong on the details. Astrobiologists started to describe the field as "50 years of theories, now 50 years of tests" around 15 years ago. And that was the time when more specific tests started, as opposed to Miller type experiments. Redox theories (submarine alkaline hydrothermal emergence) started to be tested re compartments, membranes and catalysts, as has RNA world theory on linking nucleotides with pentoses, lipid vesicle and strand replication.

We don't need to do "it" in the lab anymore than we need to replay (say) the evolution of mammals or humans to test speciation or its application to specific species. What we need to do is to be able to reject testable theories, and hopefully arrive at a topology of nested stages that robustly confirm the unity of life and planet akin to how the topology of standard phylogenies robustly show unity of species, universal common ancestry.

Nov 23, 2014
@cjn: I discussed in my longish comment why people find life here likely emerged here. Non-local emergence is even more unlikely than that it emerged out of "soup" (mainly delivered organics). Besides, impactors as such has been rejected previously (the liquid soon freeze and so move too quickly after aggregation), and Mars looks increasingly difficult. (Lost its atmosphere by hydrodynamic escape early on due to too weak gravitation).

Life emerged way before your claim. The earliest fossils are consistent with 1- billion years old Earth, genetic dating puts the first visible bacteria/archaea split as 0.8 billion. But we know from models that the late bombardment was survivable, and we know from observation that Earth was habitable (wet) at 0.15 billion of age.

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