Is there a deep, hot biosphere?

Question

Thomas Gold claims that oil is not aging vegetal or animal matter, but rather made continously from bacteria deep in the Earth's mantle (a 'deep hot biosphere') so that we would effectively never have to worry about running out.

Gold's theory is that the methane is from the Earth's interior, and cooks into oil. His Wikipedia article explains he drilled to find deep-Earth oil deposits at depths which are not supposed to contain hydocarbon deposits, and claimed to have found some but it seems that his methods have not been adopted by oil companies, because they weren't useful for finding new reserves.

What does the scientific evidence available describe as to the disposition and origin of Earth's oil resources? If petroleum is renewable, should we even worry about transitioning to a post-petroleum economy?

(I suppose this is related to this question, which was closed: https://skeptics.stackexchange.com/questions/833/is-the-worlds-oil-supply-really-diminishing-closed. I am looking for a good yardstick to evaluate the confusing variety of claims about the oil supply.)

Answer 1

There is a deep hot biosphere, but the likelyhood of that being the primary source of fuel hydrocarbons is small. There are several reasons for this. Plankton fossils in oil, higher life fossils in coal, etc. indicate that those are in fact from higher life. There are also small amounts of fuel hydrocarbons (primarily methane) that are produced deep within the earth from the chemical processes found there under pressure. However, it is believed that the "deep" sources of fuel hydrocarbons are not commercially useful.

There are very few papers on the production of fuel hydrocarbons in the way Gold hypothesizes. His thoughts have not been verified through much independent research.

Yes, there is life deep within the earth as Gold posits. However it has not been demonstrated that said life produces a significant quantity of fuel hydrocarbons. I have not yet found a paper which demonstrates that they produce any fuel hydrocarbons. Most of Gold's work seems to be concerned with showing that it's possible -- which is not the same as showing that it happens.

Paper supporting the idea that oil is a product of tiny lifeforms (bacteria, plankton, etc.):
[Microbial Origin of Fossil Fuels — osti.gov]

The bacteria/life is there:
[Long-Term Sustainability of a High-Energy, Low-Diversity Crustal Biome — sciencemag.com]

Yes, abiogenic is not exactly the question, but appears on topic, since we're discussing deep creation of hydrocarbons.

Asserts that abiogenic gases (natural gas) exist but are not commercially available:
[Energy Gases of Abiogenic Origin in the Earth's Crust — osti.gov]

Second paper supporting abiogenic natural gas exists, but not useful:
[Abiogenic Hydrocarbons and Mantle Helium in Oil and Gas Fields — osti.gov]

Again, exists, but not in significant quantity:
[Abiogenic Formation of Alkanes in the Earth's Crust as a Minor Source for Global Hydrocarbon Reservoirs — nature.com]

Would appear to assert that not only is (at least some) coal fossil based, but that it's been traced to specific plants.

Answer 2

There are several claims here. Let’s unravel them one by one.

First claim

Is there a deep, hot biosphere?

Russell has answered this: yes, there is.

Second claim

Thomas Gold claims that oil is not aging vegetal or animal matter, but rather made continously from bacteria deep in the Earth's mantle (a 'deep hot biosphere')

No, Thomas Gold made no such claim. This is probably just a misunderstanding of his argument. In fact, here is what Gold said in the “Deep, Hot Biosphere” paper:

Such microbial life may account for the presence of biological molecules in all carbonaceous materials in the outer crust

This does not mean that the carbonaceous material is formed by microbial life but rather that microbes from the deep, hot biosphere contaminate the material.

The text goes on:

and the inference that these materials must have derived from biological deposits accumulated at the surface is therefore not necessarily valid.

Thomas Gold was a follower of the theory of an abiogenic petrolium origin – i.e. that petrolium is not derived by biological processes but rather from “materials of primordial origin” (quotation from the same paper) – meaning, from before life existed on Earth.

You actually noted that yourself:

Gold's theory is that the methane is from the Earth's interior, and cooks into oil.

But you seem to think that Gold claimed the methane came from biological processes. There are in fact several proposed origins of abiogenic petroleum but even though bacteria from the deep, hot biosphere do produce methane, I cannot find any claims that this contributes significantly to petroleum production, and Gold himself certainly never made this claim [1, p 89].

Third claim

… [consequently] we would effectively never have to worry about running out [of petroleum].

False.

Thomas Gold indeed made this claim, albeit for reasons unrelated to the deep, hot biosphere. It’s hard to track down sources since they’re not online [e.g. 2, 3] but it seems that Gold’s assumptions are based on the fact that more petroleum was found in some oil reserves than was predicted.

However, modern research has effectively disproved this: there is no limitless supply of petroleum [1–3].

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[1] Geoffrey P. Glasby, Abiogenic Origin of Hydrocarbons: An Historical Overview , Resource Geology RESOURCE GEOLOGY, vol. 56(1), 2006

[2] Earth's "limitless" oil and gas reservoirs are a myth, says study, AFP, April 3, 2002

[3] Vielvoye, Roger, Gold's gas theory, Oil & Gas Journal vol. 30, February 5, 1979