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No Free Lunch, Part 3 of 3: Proof
by
Ugo Bardi & Dale Allen Pfeiffer
© Copyright 2005, From The Wilderness Publications, www.fromthewilderness.com. All Rights Reserved. May be reprinted, distributed or posted on an Internet web site for non-profit purposes only.
The Abiotic Fingerprint
January 28, 2005, PST 0800 (FTW) -- Guess what? The Earth does produce abiotic methane. It can be found in minute quantities along the world's mid-ocean ridges, venting from some volcanoes, and in some mine shafts. The amount of methane generated in these situations is minor, especially when compared to commercial natural gas reserves. As stated in part 2 of this series (and elsewhere), there is more methane produced annually from cow farts than from abiotic sources. No scientist has ever denied the existence of abiotic methane. We have said that there is no evidence that it is produced in useful quantities, and we have stated that abiotic generation of simple hydrocarbons such as methane does not indicate abiotic production of the complex hydrocarbons we refer to as crude oil.
A group of scientists from the University of Toronto has analyzed abiotic methane taken from a mineshaft in the Canadian Shield. The team, led by geologist Barbara Sherwood Lollar, took methane samples from a deep borehole in the Kidd Creek mine, located in Ontario, Canada. The mine extracts lead, silver, zinc and cadmium. The samples were taken from a depth of 6,800 to 6,900 ft. The Kidd Creek gases were a mixture of methane, ethane, H2 and N2, along with minor amounts of helium, propane and butane.1
The samples underwent isotopic analysis, quantifying the isotopes of carbon and hydrogen present in the gas.2 The isotopic ratios of a substance (particularly the ratio of carbon and hydrogen isotopes) provide us with a profile of the substance, a sort of isotopic fingerprint which indicates how the substance was generated. Most naturally occurring carbon is isotope C-12, with a small percentage of C-13 (1.11%) and a trace of radioactive isotope C-14. Organic matter, however, has a lower ratio of C-13 because photosynthesis preferentially concentrates C-12. Hydrocarbon reserves reflect their organic origin in their C-12/C-13 ratio.
Isotopic analysis of the Kidd Creek samples did not match that of organically derived hydrocarbon reserves. The ratio of carbon isotopes instead pointed to an abiotic origin. Studying the isotopic ratio of carbon in these samples-particularly comparing the ratios found in single carbon alkanes3, double carbon, triple carbon and quadruple carbon alkanes-instead suggested an abiotic origin. And when the isotopic ratios of hydrogen were also taken into account, the analysis not only indicated an abiotic origin, it also suggested how the simple hydrocarbons were generated.
Dr. Lollar and her associates found that the "isotopic trends for the series of C1-C4 alkanes indicates that hydrocarbon formation occurred by way of polymerization of methane precursors."4 They theorized an origin in rock-water interactions. The gases were closely linked to saline groundwaters and brines having 10 times the saline content of ocean water.
The carbon and hydrogen isotopic profiles of these samples finally gave us the fingerprint for abiotic hydrocarbons. As Dr. Lollar observed, "The key point is that abiogenic hydrocarbons have been talked about for a long time, but until now we didn't have a very good constraint on what they looked like."5 Now we had the isotopic fingerprint for abiotic hydrocarbons. The next logical step was to compare these isotopic ratios to those of commercial gas reserves.
Dr. Lollar and associates made this comparison in their study. "Based on the isotopic characteristics of abiogenic gases identified in this study, the ubiquitous positive correlation of d13C and d2H values for C1-C4 hydrocarbons in economic reservoirs worldwide is not consistent with any significant contribution from abiogenic gas."6
Stated again for emphasis, the study found no significant presence of abiotic hydrocarbons in commercial natural gas reserves. We cannot hope for depleted natural gas reserves to be replaced by abiotic hydrocarbons generated within the Earth. While the abiotic generation of simple hydrocarbons within the Earth has been proven, the production is very minor-especially in comparison with commercial natural gas reserves and the world demand for natural gas. There is no free lunch.
In spite of this, we are sure some proponents of the abiotic oil hypothesis will ignore the isotopic profile of abiogenic hydrocarbons referred to above. They will avoid this evidence and point to other studies which they believe support their position. "The isotopic fingerprint means nothing," they will say, "hydrocarbons have been produced in the lab using materials and conditions similar to those in the mantle." For them, this proves that hydrocarbons are abiogenic. They will sneer and say, "Let's see you generate oil organically in a lab." For the answer to this challenge, let us turn to Dr Ugo Bardi, Professor of Chemistry with the University of Florence, Italy.
The Biological Origin of Crude Oil; Where is the Proof?
Understanding the origin of crude oil is no academic question: we need oil for our everyday life and knowing where it comes from could tell us something about how long it will last. If oil comes from organic matter, as stated in the biogenic theory, it must be a limited resource, which will eventually run out. If, instead, it comes from rocks in the mantle, as the abiotic hypothesis suggests, it might be much more abundant since the mantle is so huge. In this case, oil could be effectively "limitless."
The biogenic theory and the abiotic hypothesis have been around for a long time. They both go back to 19th century when people started to become interested in that useful blackish liquid extracted from wells. As more and more studies of oil were carried out, the abiotic hypothesis was abandoned in the early 20th century and the biogenic theory became the standard explanation for the origin of oil. Recently, however, something has changed. The increase of crude oil prices and worries about the depletion of oil reserves caused a rekindling of interest in everything related to oil. So the abiotic hypothesis was also reconsidered and it was found that oil can be produced in the lab under conditions similar to those of the mantle; as indeed the hypothesis predicted.
As we said, oil is something important - indeed, vital - and it is difficult to keep a cool head when discussing it. A fairly good case can be made for the abiotic hypothesis on the basis of recent laboratory tests, but the ensuing debate has quickly gone beyond the normal rules of scientific debate to become a heated controversy. The discussion has often gravitated around statements and questions such as: "Now that we have proof of the abiotic theory, every other theory is disproved." And: "Where is the proof of the biogenic theory, anyway?" Since it seemed that no such proof could be found on the internet, it was argued that the whole idea of the biological origin of oil was a hoax and a scam. It was considered to be, actually, a conspiracy on the part of the oil companies designed to convince everybody that oil is a scarce resource and hence keep prices high.
Of course, not everybody jumped to this conclusion so quickly. But the idea that the biogenic theory is a hoax has been repeated so often in forums and blogs that it has gained a lot of ground and it has taken on the appearance of an obvious fact for some people. So we need to consider its premises in some detail. The first is that the experiment proving the abiotic theory also disproved the biogenic one as a consequence. The second is that the biogenic theory has not been sufficiently "proven." Let's examine these two points separately.
First point: Can oil, or any substance, be synthesized both biogenically and abiotically? The answer is a resounding "yes." Think, for instance, of the case of urea, a common organic substance produced by mammalian kidneys. Long ago, Leonard Wohler, a German chemist, found a way to make urea from inorganic reactants (that is "abiotically"). That caused a stir in its day because it was the first time that an organic substance was synthesized from inorganic components. However, this doesn't mean that urea cannot be formed biologically. The situation for oil is the same. Oil is formed of hydrocarbons, which are stable molecules, and it is no surprise that there is more than one route to synthesize them. Actually, another "abiotic" route to oil has been known for a long time: the Fischer-Tropsch process which uses coal, water and heat to make hydrocarbons. It was used by the Germans during the Second World War to make synthetic gasoline and it is still done nowadays in a few places. (Incidentally, the fuel obtained by this process is expensive both in terms of money and in terms of energy used to drive the reaction. So it is not a practical replacement for conventional oil, as the Germans discovered in the 1940s).
Second point: Exactly what kind of "proof" do we need of the validity of the biogenic theory of oil formation? Here, too, the example of urea can be useful. Suppose that someone had read about Wohler's abiotic synthesis of urea and, on the basis of that, claimed that all urea is created abiotically. Suppose also that this someone, in analogy with the case of oil, were to require as "proof" of the biogenic formation of urea a demonstration that it can be synthesized in a test tube starting from - say - a meal of hamburgers, fries, and beer. Maybe urea could be produced in this way but, in practice, you can't find any such "proof" on the internet or in the scientific literature. However, using the same logic required for oil, from this some people could feel authorized to claim that the biological origin ("biogenesis") of urea is not proven. They would claim that the theory is a hoax, a scam, and a conspiracy created by the pharmaceutical companies in order to sell expensive drugs to people affected by kidney ailments.
Of course, only the most extreme skeptics would claim that urea is made in abiotic kidneys from inorganic reactants. However, we find that idea absurd only because we are familiar with the basic facts of biological metabolism. We are much less familiar with the underground processes which created oil. Since nobody, it seems, ever felt that it was necessary to report on the internet that oil could be created in the laboratory starting from, say, a dead mouse, it is understandable that some people might have become confused. Still, the lack of an easily traceable proof of the biogenic oil theory should not be considered anything more suspicious than the analogous case for urea.
Furthermore, the "lack of proof" of the biogenic theory of oil formation is only apparent, not real. It is only an effect of the internet bias that tends to hide the scientific literature produced before the 1980s-1990s. The earliest successful laboratory tests to transform organic matter into oil were carried out in 1913 by the German chemist Engler. The laboratory demonstration of all the steps of the standard biogenic theory was done in a series of studies carried out by the American Petroleum Institute (API) in the 1930s -1940s. These early studies are not easy to find even in academic libraries and many petroleum geologists seem to know these results only as they are presented in later textbooks. However, this is no more an indication of a scientific conspiracy than seeing physicists calculate spacecraft trajectories without having read Newton's Principia.
However, transforming organic matter into oil is not something that occurs only in old and dusty academic journals; reports on this point can be found on the internet. Unfortunately, internet search engines are tricky, even treacherous. So, looking for "proof of the biological theory of oil formation," it is easy to miss the fact that making oil from organic substances not only was done in the lab in the past, but that it is done all the time and has been done commercially since the mid 19th century! The process that produces oil from the pyrolysis of its organic precursor ("kerogen") can be reproduced in the lab in a common test set-up called "rock evaluation" (rock eval for short) invented in 1977 and commonly carried out to characterize the oil producing potential of rocks. It is also possible to make commercial amounts of oil from the same organic precursor that commonly occurs in shales; the product is called "shale oil." The process is expensive and the amounts of commercially produced shale oil never were comparable to those of conventional oil. Still it was done, and it is being done in limited amounts today.
All this proves beyond any reasonable doubt that the biological mechanism of oil formation can be reproduced in the lab. So we can be sure of one thing: that the biological theory of oil formation has been proven as much as it is expected and necessary for a scientific theory. That means that you can't explain the rising oil prices as the result of a scientific conspiracy involving setting up a hoax called "the biological theory of oil formation." If the biogenic theory is not a hoax, it means that it is likely that oil is, after all, a limited resource. We should all consider the consequences of this fact.
The Abiotic Checklist
In this series of articles, we have systematically dismantled both the abiotic hypothesis itself, and every argument supporting it. We have pointed out the serious flaws in the abiotic hypothesis along with the logical fallacies perpetuated by its supporters. And we have shown that every bit of evidence to which abiotic proponents point can be more simply explained through the standard biogenic theory. The abiotic hypothesis has not been proven. There is no free lunch.
In closing, we turn to the eminent Australian astrobiologist and geologist, Dr. Jonathan Clarke. Dr. Clarke has produced a list of 16 observations which must be explained by the abiotic hypothesis before it can be seriously considered. We ask that abiotic supporters use this as a checklist, and please do not bother us again until you have successfully addressed each and every one of these points.
Dr. Clarke's list is as follows:
To deny this [that 99.99999% of the world's liquid hydrocarbons are produced by maturation of organic matter] means you have to come up with good explanations for the following observations.
1) The almost universal association of petroleum with sedimentary rocks.
2) The close link between petroleum reservoirs and source rocks as shown by biomarkers (the source rocks contain the same organic markers as the petroleum, essentially chemically fingerprinting the two).
3) The consistent variation of biomarkers in petroleum in accordance with the history of life on earth (biomarkers indicative of land plants are found only in Devonian and younger rocks, that formed by marine plankton only in Neoproterozoic and younger rocks, the oldest oils containing only biomarkers of bacteria).
3) The close link between the biomarkers in source rock and depositional environment (source rocks containing biomarkers of land plants are found only in terrestrial and shallow marine sediments, those indicating marine conditions only in marine sediments, those from hypersaline lakes containing only bacterial biomarkers).
4) Progressive destruction of oil when heated to over 100 degrees (precluding formation and/or migration at high temperatures as implied by the abiogenic postulate).
5) The generation of petroleum from kerogen on heating in the laboratory (complete with biomarkers), as suggested by the biogenic theory.
6) The strong enrichment in C12 of petroleum indicative of biological fractionation (no inorganic process can cause anything like the fractionation of light carbon that is seen in petroleum).
7) The location of petroleum reservoirs down the hydraulic gradient from the source rocks in many cases (those which are not are in areas where there is clear evidence of post migration tectonism).
8) The almost complete absence of significant petroleum occurrences in igneous and metamorphic rocks.
The evidence usually cited in favor of abiogenic petroleum can all be better explained by the biogenic hypothesis, e.g.:
9) Rare traces of cooked pyrobitumens in igneous rocks (better explained by reaction with organic rich country rocks, with which the pyrobitumens can usually be tied).
10) Rare traces of cooked pyrobitumens in metamorphic rocks (better explained by metamorphism of residual hydrocarbons in the protolith).
11) The very rare occurrence of small hydrocarbon accumulations in igneous or metamorphic rocks (in every case these are adjacent to organic rich sedimentary rocks to which the hydrocarbons can be tied via biomarkers).
12) The presence of undoubted mantle derived gases (such as He and some CO2) in some natural gas (there is no reason why gas accumulations must be all from one source; given that some petroleum fields are of mixed provenance, it is inevitable that some mantle gas contamination of biogenic hydrocarbons will occur under some circumstances).
13) The presence of traces of hydrocarbons in deep wells in crystalline rock (these can be formed by a range of processes, including metamorphic synthesis by the Fischer-Tropsch reaction, or from residual organic matter as in 10).
14) Traces of hydrocarbon gases in magma volatiles (in most cases magmas ascend through sedimentary succession, any organic matter present will be thermally cracked and some will be incorporated into the volatile phase; some Fischer-Tropsch synthesis can also occur).
15) Traces of hydrocarbon gases at mid ocean ridges (such traces are not surprising given that the upper mantle has been contaminated with biogenic organic matter through several billion years of subduction, the answer to 14 may be applicable also).
16) Traces of hydrocarbons in hydrothermal fluids; these are also all compositionally consistent with derivation from either country rocks or Fischer-Tropsch synthesis.
The geological evidence is utterly against the abiogenic postulate.
We fully agree with Dr. Clarke: the geological evidence does not support the abiogenic hypothesis.
For years conmen have managed to persuade the unwary that they can get something for nothing. They do so by playing on the fears and greed of their "mark." Yet, in the end, the "mark" always learns - too often the hard way - that there is no free lunch.
Now humanity as a whole is about to learn this most difficult lesson. Let us hope that we do not provide an "easy mark."
There is no free lunch.
1 "Abiogenic formation of alkanes in the Earth's crust as a minor source for global hydrocarbon reservoirs," Lollar, B. Sherwood, et al. Nature 416, pg. 522-524; April 4, 2002. http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v416/n6880/abs/416522a_fs.html.
2 Isotopes are atoms which have the same number of electrons and protons, but a different number of neutrons. Therefore, they have the same atomic number, but different atomic mass numbers.
3 Alkanes: hydrocarbons having the general formula CnH2n + 2, where n = 1,2….
4 Op. Cit. See note 1.
5 "Gas Origin Theories to be Studied," Brown, David. AAPG Explorer; November, 2002. http://www.aapg.org/explorer/2002/11nov/abiogenic.cfm.
6 Op. Cit. See note 1.
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