PLEASE HELP !!!

"Jeff Root" wrote in message
om...
"George" replied to Jeff Root:

From the disorganized bits and pieces of info I've come across
over the years, I've gotten the impression that coal formed
from woody plants, until the first fungi or bacteria (which?)
capable of digesting cellulose developed. And that oil formed
from the bacterial mats which I gather were the only life form
on Earth for a billion years or more. Are those impressions
about right?

Sure, woody plants like lepidodendron, but also peat, ferns, and
other plants as well. I've seen fossilized logs brought out of
mines that weighed as much as four tons, and were ten feet long,
and three feet in diameter. As for the bacterial mats, I don't know
that I would go so far as to say that they were that significant to
the diagenesis. That is, bacteria were certainly important in the
reducing environment of the marshes and swamps that eventually
formed the coal. But it is also important to understand the
importance of pressure and temperature of the coal forming process.

You imply here and below something that you don't actually say,
and which I have never heard befo That coal formed from oil.

What? No. You misunderstand me.

Ok. That's a relief. :-)

The decomposition products of marsh and swamp deposits (decomposed
organic matter) form coal under similar chemical and environmental
conditions. You can even get oil out of coal, hence the coal
gasification process. But oil is different in that being liquid,
not solid, it is more refined, and can migrate through porous rock
where it gets trapped into reservoirs in geologic structures.

How well are coal and oil formation processes understood?

Very well.

Is water in large quantities ("marsh and swamp") thought to be
essential for both processes?

I don't know how important they are for the formation of coal, but there is
usually a lot of ground water in most ground water that has to be contolled
during the mining process. Many water wells in Eastern Kentucky are
contaminated with iron and natural gas originating from the coal. Of
course, oil usually migrates with a lot of water, and is usually saturated
brine water, which also has to be controlled.

Or would very small quantities
(maybe just humid air) suffice?

Air is not really a large at all in either, since they nearly always form in
a reducing environment.

Did the source matter have to
be buried, or could coal and/or oil form while exposed at the
surface (perhaps in a very different atmosphere from today's)?

Coal is formed after burial, pressure of compaction, and moderate heating
(100 degrees C or less). Oil is formed through several processes, always in
a reducing environment, but always within the subsurface. Sometime it seeps
to the surface, but have already formed at that point.


I would interpret "more refined" to mean "more changed from the
original mix of material" and "more separated into its component
parts".

As I understand it, more refined means the process (much of which involves
biological digestion, a conversion process, and heating under pressure in
the subsurface) has purified the oil, removng impurities and compounds which
the bacteria digest, such as sulfur, although sulfur is usually one
component that has to be removed during the refinement process before it is
used. It is usually separated in the sense that in its early stage of
formation the brine water is intermixed with the oily solution, as well as
some gas. The refinement process in the ground creates a lot of natural gas
that is usually burned off when the oil is recovered.

Is that what you mean? Does crude oil contain fewer
different compounds than coal?

Oil contains more compounds, but they are not all the same. Coal contains
more phenyl compounds, and more creosote, whereas oil contains more
polynuclear aromatic compounds like naphthalene, acenapthylene, etc. Both
contain a lot of carcenogenic compounds.

Has the vast majority of the oil in the ground migrated and
pooled, or is a large fraction of the total just a minor
contaminant in the rock which contains it? Or what?

Understand that when an oil field is developed, the most that can be
recovered is in the neighborhood of 20%. The rest is locked up in much less
permeable rock, or consists of heavier fractions, like tars.. And after the
pressure is reduced from pumping, usually water or steam has to be injected
into the reservoir to increase the pressure and extract more oil. Sometime
the rock is fractured with explosives to increase permeability. Removing
the remaining 80% has long been a tremendous problem and expense for the oil
industry. But as for whether most is pooled or just a minor fraction of the
total, most porous sedimentary rocks contain some minor amounts of
hydrocarbons. The question for oil companies is what can be recovered.
Most is not mature enough to use, or of not enough quantity to justify the
expense of recovery. So I would say that most oil in the ground is in small
quantities. The large reservoirsare rare. Many wells show what at first
appears to be large plays, but end up tapering off quickly to much lower
recoverable amounts.


That coal formed from oil.

Not at all. As I stated above, coal is formed from the
decomposition of organic matter (peat, dead trees, ferms, and
other plant and organic material). But oil is found in some
coal, and can be extracted from it.

I was under the impression that oil formed over a much longer
period than oil did, much longer ago, and from different source
material.

That is mostly true. However, oil is also found in coal, and can
be extracted from it. Many of the same hydrocarbons found in coal
are also found in oil.

But you imply that the difference between coal and oil is that
coal is oil which has undergone further changes in the Earth.
Is that what you're saying?

No, its the other way around, but not in all cases. Both form
in reducing environments, but oil is mobile, and can migrate, as
mentioned above.

I don't see why you emphasize that fact. It may be crucial
to where the oil is found today and how it is extracted, but
doesn't appear to have anything to do with how it formed.
Coal and oil seem to usually be found separate from each other.
Not miles apart, but hundreds or thousands of miles apart.

That is not really true. The first oil field developed in Kentucky, for
instance was in the Eastern Kentucky coal field. The first oil fields
developed in West Virginia and Pennsylvania was developed in proximity to
bituminous and anthracite coal deposits. The Oil in the Persian Gulf and in
the Southern US formed under different circumstances. That oil was formed
from the decay of rapidly buried plankton and reef deposits, as was the oil
found in Texas, Oklahoma, and the gulf of Mexico.


You said in your first reply:

As for the bacterial mats, I don't know that I would go so far as
to say that they were that significant to the diagenesis. That is,
bacteria were certainly important in the reducing environment of
the marshes and swamps that eventually formed the coal.

Do you mean you don't think oil formed from bacterial mats?

What I mean is that although bacteria plays a huge role in the formation of
oil, the source material in many locations is usually plankton, organic
material from reefs, and algae. The bacteria decays this material after
burial in a reducing environment. And of course, oil is also produced as a
result of the formation of coal.

Since nothing had evolved yet to eat the bacteria, there must
have been plenty of organic matter available. I guessed that
that is the reason there is so much oil in the Earth today:
A billion years or two worth of dead bacteria piled up.


Actually, 70% of all oil is of Mezozoic age, 20% is of Cenozoic age, while
10% is of Paleozoic age. No oil reserves have been found to be older than
Paleozoic age.

As such, much of the parafins, volatailes and long chain
hydrocarbons would have been removed from the coal if the
temperature had been much higher than this, rendering most
of it useless as a fuel source.

Longer chains break down first? Do they break into random-size
pieces or do tiny pieces (such as methane and ethane) break off
from the big ones? What happens to the bits? Do unbranched
chains break down at lower temperature than branched chains?

I don't know the exact sequence, but I would assume that the
volatiles outgas first (such as methane, benzene, toluene,
ethylbenzene, and the xylenes, etc. The longer chains would
obviously take longer to break down, as we see in the difficulty
in cleaning up many oil spills and discharges into soil and
ground water of heavy fractions such as #2 fuel oil, and diesel.

That doesn't directly confirm my guess: That you were saying
that paraffins and other long-chain hydrocarbons are the first
to break down when the temperature goes up. Is that what you
were saying?

No.

I wasn't suggesting that bacterial mats had *anything* to do
with the formation of coal-- just oil. But I know that some
modern-day bacteria, like many fungi, are able to digest
cellulose. I wondered whether the advent of those cellulose-
eating bacteria and/or fungi brought an end to coal formation.

Good question. Sounds like a dissertation paper for someone to me.
Interested?

Me? Moderately interested, but highly incompetent.

-- Jeff, in Minneapolis


Everyone starts from lack of knowledge. Edison was a kluts and misbehaved
in school. His acheivement was that he was an obsessive-compulsive. He
rarely slept, and was constantly thinking about how to make things and solve
problems. He wasn't particularly intelligent, or particularly well liked,
just determined, and he stole some of his best "inventions". Sometimes
people just get lucky. I'm not a particularly talented geologist (at least
I don't think so). But I was lucky enough to stumble, along with a partner,
across one of the most significant Mississippian-aged crinoid locations in
the Central US about 15 years ago (30 genera, 74 species, 8 new species, two
new genera, and five specimens that were more complete than the holotypes).
We also found crinoid stems that were over 7 feet long, and 3/4 inch in
diameter. For me, it was a find of a lifetime. We were actually looking for
minerals. Like I said, sometimes you just get lucky. It often takes a lot
of hard work, but if you enjoy the work, and are forever inquisitive, you
can acheive a lot.