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Re: Did Dinosaurs BECOME Oil?



>
>On Mar 22, 12:26, Art Berggreen wrote:
>} Subject: Re: Did Dinosaurs BECOME Oil?
>> >
>> >This is roughly correct.  There is some reason to suppose that oil
>> >formation is still going on, for instance in the Mississippi Delta.
>> 
>> I believe planktonic "oozes" in isolated ocean basins is a more likely
>> environment.  I'm not sure what the percentage of organic matter in the
>> delta is, but I'd suspect too much non-organic silt.
>
>There's an awful lot of oil in the Mississippi Delta.  We (Unocal) do a lot
>of oil drilling there.  I think a lot of organic material flows out of the
>deltas in addition to the silt.
>
>> >>From what little I have read, my impression is that oil mostly
>> >forms from the degradation of microplankton when rapidly buried
>> >and heated, as might happen in a major river delta.  I have not
>> >heard any serious proposals for any other substantial source.
>> 
>> Just change river delta to ocean basin and I fully agree.
>
>I'm not on the geological side of the oil exploration business here at
>Unocal, but I do know that we do a *lot* of oil drilling in major river
>delta areas, like the Mississippi, the Mahakam (Indonesia), and the Chao
>Phraya (Thailand) deltas.  Those are, in fact, our 3 most important oil &
>gas fields. 
>
>Oil migrates through the rock.  Yes, there's lots of silt, but the burial &
>heating liquefies the oil & gas, and it migrates through porous rocks.  We
>look for traps where it collects, which can be some distance from where it
>was originally deposited.    This also has the effect of concentrating the
>oil much more than the original hydrocarbon deposit was concentrated.

Thanks for your input, I don't recall hearing about oil in river deltas.
It may be that the emphasis around here are the marine basins that created
the oil deposits (and apparently are still creating the conditions for oil
formation).  Around here much of the oil is associated with diatomites which
contain impervious layer which prevent the migration of the oil.  The
drilling platforms off the coast follow anticlines where the oil has
collected under the trapping layers.  We have many places where these
reservoirs reach the surface and create the natural petroleum seeps
that plauge local beaches.

Any idea what the primary source of the organic material is?  Plankton?

Art