How Oil Is Formed

turbo

Swamps, lagoons, etc that harbored simple life that could have ended up as the precursors to oil probably also harbored complex life (fish, crocodilians, reptiles, etc) which also joined the sediments at the bottom. If the water was anaerobic, then the macro-creatures didn't rot, either, and could have ended up being a part of what became oil. It pretty much all depends on at what era the oil precursor sediments were laid down.

StuffIThink

Icthyosaurs that were oceanic dinosaurs.

Probably a few of them turned into oil for sure.

Ophiolite

The wording is that "some oil deposits contain dinosaurs". Perhaps I am too much of a literalist. Decaying organic material, generally microscopic animal life, deposited - as others have noted - in anoxic conditions is converted to kerogen. Such deposits are typically fine grained i.e. clays, which - through diagenesis - will go on to become claystones and shales. The kerogen then undergoes further chemical changes to release oil, which migrates into the oil reservoirs.

General usage would have reserved the phrase 'oil deposits' for these oil reservoirs, not for the source rocks which are, not surprsingly, called source rocks, not oil deposits.

Now it is entirely possible - indeed, I think a virtual certainty - that some of these reservoir rocks containing oil also contain dinosaur remains. But those dinosaurs are not the source of the oil that has migrated there. Equally, the occassional stray dinosaur, washed out to sea and sinking to the bottom where it is buried by a turbidity current deposit, may assuredly contribute its tiny mass to the developing kerogen.

I, however, am unaware of such an event ever having been identified, not because it may not have occured, but because it would exceedingly rare. If it has been documented then I would really like to read about it. Hence I asked for a citation.

for StuffIThink - Icthyosaurs are not dinosaurs.

Studiot

Someone from nitpickersanonymous.org whispered in my ear

are not?

Where can I meet one? I thought I was the last living dinosaur left on the planet.

Ophiolite

Speaking as a former student palaentologist I can assure you that icthyosaurs still are very definitely around and some stunning examples can be see at the Natural History Museum in South Kensington, London. :)

DaveC426913

Yeah. I think "are" implies "still alive".

You got news about a live ichthyosaur? I'd like to discuss it with you. Meet me in the back alley at midnight. Come alone.

Ophiolite

To normal people, yes, but not to palaeontologists. I mean if they are alive they have all this squishy soft stuff that you have to remove to look at the bones.

DaveC426913

wondering2

I wonder if it is possible for the heat and presure at lower levels in the core can produce "oil" and "natural gas" without the need to bury small or large animals and plants several miles deep?

Just Wondering2

cmb

In the form D-limonene, it is used [increasingly] as a solvent for other oily substances too, being much safer and environmentally benign than chlorinated hydrocarbons.

cmb

There is a theory to this effect by a chap called 'Gold' I believe. If I find a link I'll post, but you'll likely have luck searching for 'Abiogenic Petroleum'.

Dotini

Thomas Gold, eminent physicist (Cambridge, Harvard, Cornell), wrote "The Deep Hot Biosphere". A very good read.

Respectfully submitted,
Steve

cmb

...I'll be waiting to hear what he has to say, then, once he's a physicist!

Evo

To my knowledge the abiogenic oil hypothesis isn't accepted.

http://en.wikipedia.org/wiki/Abiogenic_petroleum_origin

Dotini

Thanks for so tactfully pointing out my spelling error. I have corrected it.

I have in my hand a carbonaceous chondrite, which I would like to throw at you.
http://en.wikipedia.org/wiki/Carbonaceous_chondrite

As for hearing what Gold has to say, you're a little late, since he died in 2004.

Respectfully,
Steve

cmb

_{(Sorry, Dotini, I could not resist that one!)}

cmb

So, just as an aside on this - a story line to some sci-fi story, maybe!...


Lovelock (Gia fame) has proposed what sounds to me like the only really practical way for carbon capture. This is to turn trees into charcoal (thus getting a little energy out of them to make it worth while) and then burying it.

As far as I can tell, this is the most practical way of doing it, so if we are going to do it, then, on the basis that the most practical things come to pass eventualy, then that'll eventually happen.

The 'story line', then, is that the coal we have today is the past attempt at carbon capture, by this method, of a civilization who left it too late to clean up their carbon emissions!