Hydrocarbons in the deep Earth?

July 26, 2009
This artistic view of the Earth's interior shows hydrocarbons forming in the upper mantle and transported through deep faults to shallower depths in the Earth's crust. The inset shows a snapshot of the methane dissociation reaction studied in this work. Credit: Image courtesy A. Kolesnikov and V. Kutcherov

The oil and gas that fuels our homes and cars started out as living organisms that died, were compressed, and heated under heavy layers of sediments in the Earth's crust. Scientists have debated for years whether some of these hydrocarbons could also have been created deeper in the Earth and formed without organic matter. Now for the first time, scientists have found that ethane and heavier hydrocarbons can be synthesized under the pressure-temperature conditions of the upper mantle —the layer of Earth under the crust and on top of the core. The research was conducted by scientists at the Carnegie Institution's Geophysical Laboratory, with colleagues from Russia and Sweden, and is published in the July 26, advanced on-line issue of Nature Geoscience.

Methane (CH4) is the main constituent of natural gas, while ethane (C2H6) is used as a petrochemical feedstock. Both of these hydrocarbons, and others associated with fuel, are called saturated hydrocarbons because they have simple, single bonds and are saturated with hydrogen. Using a diamond anvil cell and a laser heat source, the scientists first subjected to pressures exceeding 20 thousand times the at and temperatures ranging from 1,300 F° to over 2,240 F°.

These conditions mimic those found 40 to 95 miles deep inside the Earth. The methane reacted and formed ethane, propane, butane, molecular hydrogen, and graphite. The scientists then subjected ethane to the same conditions and it produced methane. The transformations suggest heavier hydrocarbons could exist deep down. The reversibility implies that the synthesis of saturated hydrocarbons is thermodynamically controlled and does not require organic matter.

The scientists ruled out the possibility that catalysts used as part of the experimental apparatus were at work, but they acknowledge that catalysts could be involved in the deep Earth with its mix of compounds.

"We were intrigued by previous experiments and theoretical predictions," remarked Carnegie's Alexander Goncharov a coauthor. "Experiments reported some years ago subjected methane to high pressures and temperatures and found that heavier hydrocarbons formed from methane under very similar pressure and temperature conditions. However, the molecules could not be identified and a distribution was likely. We overcame this problem with our improved laser-heating technique where we could cook larger volumes more uniformly. And we found that methane can be produced from ethane."

The products did not change for many hours, but the tell-tale chemical signatures began to fade after a few days.

Professor Kutcherov, a coauthor, put the finding into context: "The notion that hydrocarbons generated in the mantle migrate into the Earth's crust and contribute to oil-and-gas reservoirs was promoted in Russia and Ukraine many years ago. The synthesis and stability of the compounds studied here as well as heavier hydrocarbons over the full range of conditions within the Earth's mantle now need to be explored. In addition, the extent to which this 'reduced' carbon survives migration into the crust needs to be established (e.g., without being oxidized to CO2). These and related questions demonstrate the need for a new experimental and theoretical program to study the fate of carbon in the deep Earth."

Source: Carnegie Institution

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1.2 / 5 (9) Jul 26, 2009

The inventory of radiogenic and primordial noble gases (He, Ne, Ar, Kr and Xe) in the Earth and its atmosphere indicate that the Earth formed in layers, i.e., heterogeneously, beginning with the formation of its iron core from abundant iron meteorites near the Sun [See "The noble gas record of the terrestrial planets, " Geochemical Journal 15 (1981) 247-267].

According to that scenario, lightweight elements like H, C, and N were added as a late veneer and would not likely exist in the deep interior of the Earth.

See also http://www.physor...740.html

With kind regards,
Oliver K. Manuel
3 / 5 (8) Jul 26, 2009
I'm sure Exxon/Mobil knew this well before now.
1 / 5 (4) Jul 26, 2009
That coal came from living matter is not in question. Oil, however, has always seemed to me to be more likely the result of geologic forces.
Interesting to see oil being produced _now_ in the Bass Strait near Melbourne.
4.3 / 5 (7) Jul 26, 2009
Methane can also be produced inorganically through the geological process of serpentisation (Hydration) of olivine rich rocks (peridotites). Peridotites are common in the upper mantle. The frozen clathrates of methane found on the ocean floor are thought too have this origin.
3.7 / 5 (3) Jul 26, 2009
Zygo - do you mean that hydroxides and carbonates combine to form methane and ?? MgO. Is this a source of naturally occuring periclase?
5 / 5 (4) Jul 26, 2009
Wouldn't carbon isotope distributions indicate whether particular hydrocarbons were from living sources?
4.2 / 5 (5) Jul 27, 2009
I'm sure Exxon/Mobil knew this well before now.

You assume a great deal. Bureaucracies are rarely that intelligent and the right hand never knows what the left is doing.

However, there have been Russian (former Soviet era 1950s until present) geo-scientists saying this for decades. See abiogenic petroleum origin.

A third alternative is that some/most of the hydrocarbon in the lithosphere were brought by meteors.

Neither of these methods preclude a biogenic origin for petroleum.

And in response to Mr Manuel above; the planet probably accreted over 3 or 4 hundred million years and remained completely, or nearly, molten for several 10s of millions of years after accretion was completed. This was sufficient time for the majority of heavy elements to stratify.

When the Mars sized body struck the proto-earth, forming the Moon, it caused the entire planet to become molten, again. The impact blasted away most of theproto-earth's light rocky crustal material and left much of the impactors heavy elements behind (see composition of Luna), which sunk into the outer core. Again more stratification of Earth.

The late heavy bombardment at 3.9Gya probably remelted the lithosphere, causing yet more stratification of light and heavy elements.

Yet, the mantle contain a minimum of several world oceans of H2O in it structure. This does not fit your description of events, but at least it is a testable theory (unlike others often presented here).
3.4 / 5 (5) Jul 27, 2009
Wouldn't carbon isotope distributions indicate whether particular hydrocarbons were from living sources?

There is oil coming from vents in the Sea of Cortez that is less than 2000 years old. However, most petroleum is so old that the Carbon 14 has long since decayed into Nitrogen (half life of 5730 years).
2.3 / 5 (3) Jul 27, 2009
Could we see the possibility of carbon sequestering into the mantle to 'cook up' some more hydrocarbons and turn oil into a renewable resource?
2.3 / 5 (6) Jul 27, 2009
Xpst was referring to C12:C13 ratios, as it is well known that plants preferentially fix carbon 12 during photosynthesis.
1 / 5 (1) Jul 27, 2009
So, oil on the moon?
2.6 / 5 (5) Jul 27, 2009
Oil on a lot of planets. Also, peak oil is B.S. Oil fields that were capped off decades ago are mysteriously full of oil again. That doesn't mean we need to keep burning it though. It screws up the environment, and there's evidence to suggest that it serves as a lubricant and that removing it can sometimes cause earthquakes.
1.7 / 5 (6) Jul 27, 2009

And in response to Mr Manuel above; the planet probably accreted over 3 or 4 hundred million years and remained completely, or nearly, molten for several 10s of millions of years after accretion was completed. This was sufficient time for the majority of heavy elements to stratify.

Not at all!

That scenario is directly falsified by quantitative data on primordial and radiogenic noble gas isotopes in air and still remaining inside planet Earth today, especially:

1. Primordial He-3 and Ne-20 still inside the Earth, and

2. Radiogenic Ar-40 from the decay of K-40,
___Radiogenic Xe-129 from the decay of extinct I-129, and
___Fissiogenic-Xe from the decay of U and extinct Pu-244

In air and inside the Earth today.

See "The noble gas record of the terrestrial planets " [Geochemical Journal 15 (1981) 247-267]. http://tinyurl.com/2k8ds3

With kind regards,
Oliver K. Manuel
1 / 5 (2) Jul 27, 2009
while it has never made any sense to me that they said oil came from dead animals and plant life (ie why isnt oil found everywhere?) i think saying its made in the crust is slightly more unbelievable, might as well say aliens did it and hope they come back to make some more! :)
3.7 / 5 (3) Jul 27, 2009
Mr Manuel

Mars was molten for at least 100 million years after accretion.

Mars molten past - UC Davis http://www.news.u...?id=8436

Earth was molten longer.

(3/2)kT ~ M ~ volume ~ r^3

The rate at which the planet can cool is proportional to the surface area from which it can radiate away that heat to outer space, and surface area for any object is proportional the radius squared.

Cooling rate ~ surface area ~ r^2

So, if you consider larger and larger planets, r3 certainly rises faster than r2 and therefore larger planets will cool slower. The earth is the largest inner planet, and we would then expect that the earth would be cooling the slowest and have retained the largest fraction of its initial heat.

Good day
2.5 / 5 (4) Jul 27, 2009
The Russian deep drilling methods that have been highly successful are predicated upon the idea of the earth creating the oil itself. Thus, all of their drill hole locational choices are based upon such thinking.

The vast majority of these drill operations have been successful in finding oil.

Western drill operations are predicated upon scarcity and then pricing and control via oil corporations. As well, they are predicated upon 100 year old thinking about biomass creating oil. Talk about old unproven science keeping reign on people's thinking and maintain scarcity and control. On all levels. Think about it.

Thus, in the western world of science and corporations, the western world would be the last to know or understand that the earth itself forms oil. In a method similar to that of the creation of acetone and similar. Good old standard alchemy.

You know--chemistry. The soviets got it right.

Now that the oil shale and the oil in Montana, etc (100 trillion barrels) have been found, they'll have to find another way to control us.

Yes, the ever ambiguous 'they'. They exist - and do so in every generation. Start looking for them, punkass.
1 / 5 (4) Jul 27, 2009

Mr Manuel

Mars was molten for at least 100 million years after accretion.

Mars molten past - UC Davis http://www.news.u...?id=8436
Good day

Sorry, Shootis. You are wrong about Mars too.

Read the paper cited above, Shootist, and perhaps you will understand that it discusses the noble gas record of MARS as well as EARTH.

See "The noble gas record of the terrestrial planets " [Geochemical Journal 15 (1981) 247-267]. http://tinyurl.com/2k8ds3

With kind regards,
Oliver K. Manuel
2.5 / 5 (2) Jul 28, 2009
There is a pretty simple argument against the existence of abiogenic oil, at least in significant amounts. If there is abiogenic oil being made, it is either being made slowly enough and in small enough quantities that excess oil is degraded at the surface by the normal weathering and bacterial processes, or it is being made faster than that. If it's being made slowly enough to be degraded normally, then that is far too slow to replenish the oil reservoirs as we extract the oil, as it takes thousands of years to degrade. If it's being made faster than that, it would have accumulated in huge lakes or even seas of oil on the surface over the millions of years that it's been generating. Since we aren't swimming in oil on the surface of the planet, it must not be generating faster than the (very slow) natural degradation process. Here's one of the many summaries of that argument: http://www.fromth...il.shtml
1 / 5 (3) Jul 28, 2009
Always suspected that most hydrocarbons were of cosmological rather than biological origin. Oil does accumulate in large fields at the surface-look at the tar sands. Where is the magnesium from all the chlorophyl of the decayed plant life. And how does one explain the large amounts of sulfur or vanadium. There is just too much oil and its found too deep to be biogenic origin. It does not need to be continuously produced to be abiogenic. Just look at Titan- a massive cosmological reservoir of hydrocarbons. Drives me nuts when I hear "fossil fuels' . And Dr Manuel-love your theory about the sun being the super nova that generated the solar systems elements. Mavericks are usually right.
4 / 5 (2) Jul 28, 2009
Kind of old news ... but kind of nice.

Physicist Thomas Gold championed this some time ago and he was preceded by Soviet scientists. Of course, he was largely derided until his death. He published a book in 1999 called "Deep Hot Biosphere - the Myth of Fossil Fuels". Nice to see his clear thinking getting its due even if it is posthumously.
2 / 5 (3) Jul 29, 2009
I have always believed there is a plutonic component in the hydrocarbon scheme. When a geologist is preparing a possible prospect, many of them resort to hydrocarbon migration from a 'deep kitchen'. It seems to work as well as anything. Of course I also know a man who became a millionaire by 'witching' the locations of his wells. He could tell me how deep and what the water cut was. People laugh but he was the one who made the money. Laughing to the bank. The world is full of science. It is also full of magic. Ain't life grand? By the way, oil companies do not and have not set the price of their own product or we would not go through the feast and fammine cycle we do. We are not allowed to make money and feel good about it. Guess what? We are independent capitalists and never have and never will produce for governments who are worse than any coproation I have ever heard of. I detest socialism and will fight and die against communism or any form of theocracy. Socialists are fools and humans are not bees.
not rated yet Aug 02, 2009
Um, put me in the "BS" category here. Yes, methane can be converted under various conditions to other hydrocarbons ... but its damn hot down there and even in the experiment it rapidly changes to C02. It burns and would need a very quick route out to avoid that. Most oil is found where it is expected -- in ancient river deltas that were organic carbon collectors near sand banks getting progressively covered in salt so that the oil can migrate but get trapped in salt domes.

Yellowstone is about as direct connection to deep earth as you can get. Hawaii is another direct connection. No oil in either one. This theory is just non-sense.

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