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Fossil Fuels and Primordial Methane
Name: Glenn
Status: Other
Grade: Other
Location: LA
Country: United States
Date: May 2008
Question:
Since early school days we were taught that gas and oil are pools of
"fossil" fuels, meaning that they originated eons ago from plant and animal life.
Yet on planets and moons far from the Sun where life is believed to be unlikely,
our space probes are finding seas of frozen methane. Is it possible, or even
likely, that our "fossil" fuels may have formed through geophysical processes
and that there be a lot more down there somewhere?
Replies:
The "American" school of thought tenaciously holds that fossil fuels come from the
decay of plants -- to the point of making the question closed. The "European" and
"Russian" schools of thought are much less dogmatic on the question.
In my opinion, there are some questions that the biotic sources of fossil fuel do
not address adequately. A couple of examples: Why is helium found almost
exclusively in natural gas deposits? Why are metals such as vanadium and manganese
found abundantly in natural gas deposits? If decayed vegetable matter (containing
chlorophyll) is the source of fossil fuels, there should be large amounts of
magnesium. But there does not appear to be such an excess.
The late Thomas Gold wrote a book "The Deep Hot Biosphere" which delves into these
and other issues challenging the "American" school of thought. Thomas Gold is not
some "goof ball" out there. He was/is a respected mainline geologist /
astrophysicist.
I think that the formation of "fossil fuels" is a lot more complicated than the
"American" model insists is the only possible answer.
Vince Calder
Glen,
This is a very interesting idea - one that I had not thought about. However, I
think that there is sufficient evidence to suggest that the fossil fuels and
methane found in other planets have different development histories. It could be
argued that the very early histories of the planets all had the "reducing
atmosphere" necessary to develop the short chain hydrocarbon pools (methane,
ethane, etc.). This reducing atmosphere (a lack of oxygen) which -through
geophysical processes- develop the short chain hydrocarbons and prevent the
oxidation of such compounds to more stable gases of carbon dioxide and so on
could have existed in all the planets and moons in the early history of the solar
system. However, while the other planets and moons still have this reducing
atmosphere, the Earth, contained enough oxygen to convert such compounds into
carbon dioxide (again through normal geophysical processes) which in turn was
converted by plant life to more oxygen until we now have a relatively oxygen rich
atmosphere. Moreover, we find that fossil fuel deposits contain more than just the
short chain hydrocarbons. Medium length hydrocarbons such as octane and dodecane
also exist in these deposits - compounds which we do not find in abundance in
other planets and moons. Such compounds could only come from organisms that were
able to develop organized and complex organic structures. Finally, we can determine
the time period that these fossil fuel deposits developed (through radioactive
dating) and know that they were developed in the time that plant and animal life
already existed on Earth. Since pools such as those in other planets and moons
can only form from direct condensation from an organic rich atmosphere, then this
could not have existed on Earth where higher organisms required oxygen to
breath.
Greg (Roberto Gregorius)
Present ideas on the origins of the solar system have most lighter, gaseous
compounds being moved to the orbits of the outer planets by the solar wind.
This leaves little "primordial methane" in earth's orbit, but lots of solid
materials.
In addition, most deposits of oil and gas are associated with carbon rich source
rock, like shale. Often, the type of hydrocarbon found can be predicted by
looking at how hot the source rock once was (its thermal maturation). This
supports the creation of natural gas from "fossil" sources.
HOWEVER, the idea of "abiogenic gas" has long interested by some of the more open
minded geologists in the oil industry. A number of years ago, say about 30 - 40,
a geologist named T. Gold convinced the Swedish government and private investors
to drill a gas/oil well in the Siljan Ring, a circular feature in granite located
north of Stockholm. Granite, being igneous and once molten, is not the place you
would normally look for oil or gas. But Gold thought cracks in the granite might
reach deep enough to get at some of the "primary methane". Claims were made of
small amounts of oil being found in the well, but to my knowledge, these were not
substantiated.
Yet, I recently read an article about some scientists who were investigating the
idea of primary methane. It looks as if the idea is still attractive to serious
researchers.
Robert Avakian
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Update: June 2012
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