>They could only create a small amount of longer chain hydrocarbons in a closed experiment at high pressure high temperatureOf course What were you expecting? A gigaton of oil from 0.6cm^3 of ingredients? The experiment was not to try mass production of petroluem, but merely to demonstrate it was chemically possible at mantle conditions.
> at high temperature low pressure all that forms is methaneFine by me. Abiotic oil doesn't require petroleum generation at low pressure. Your biogenic oil theory does though.
So even if a liquid hydrocarbon formed ... as it rose up through the mantle and lower crust, temperature is still far above the stability range for liquid but pressure has dropped well below the point at which the paper indicates they could only create methane.
Yes I gathered this is centrepiece in your objection to abiotic theory, the one you hang your hat on. And I think you are right - suddenly depressurized hot oil will decompose. Like a deep ocean fish shot with a 100 yard cannon into the vacuum of space, the shock of depressurization would crack it.
I expect this is what quite a few natural gas reserves are, abioitic petroleum that has depressized too quickly. So you win there, well done.
But, you are your own worst enemy. You totally telegraph your own worst fears. I learn from you about what's going in the Earth by discerning from your excited words what you are guarding against. And so this fixation you have for sudden depressurization tells me what is actually happening.
The 100 yard cannon is a poor analogy for how some mantle fluids upwell. Deep rocks are tight. Upwelling migration is slow. Under an upper crust oil bearing formation, thousands if not millions of small trickles of abiotic oil filter thru fractures in deep layer rocks over a wide area. This wide area and slow speed allow cooling by conduction to keep pace with pressure drop, enough that a significant amount of petroleum doesn't crack. Hence a nice pool of abiotic petroleum collects in the upper crust, or even makes it to the surface.
This is simple and intuitive behaviour such that abiotic theorists haven't felt the need to concentrate on it much. I guess if more biotic rockdocs cry about it, then someone will do experiments to demo it.
This paper outlines upper crust petroleum field creation in chapter 3.
http://onlinelibrary.wiley.com/doi/10.1 ... 00270/fullthere is no limestone existing in the mantle where these pressure occur, it was long melted and completely dissociated during the subduction phase.
You've no idea how tied up in geology myths you are. Your interpretation of geology is grounded in the idea that atomic elements and basic chemicals are created by biology, and then find their way slowly into the earth.
The reality is its the other way round. Limestone is a product of the mantle, just like petroleum. It's creation has absolutely nothing to do with biology. You have drawn wrong conclusions from minerals with animals and animal remains in them. Just as with footprints on the moon, the signature of biology in minerals doesn't mean it was made by biology. Its a dumb mistake to make, but i forgive u.
Subduction is bulshit too.