The claims for the abiotic theory often seem overstated in other ways. J. F. Kenney of Gas Resources Corporations, Houston, Texas, who is one of the very few Western geologists to argue for the abiotic theory, writes, "competent physicists, chemists, chemical engineers and men knowledgeable of thermodynamics have known that natural petroleum does not evolve from biological materials since the last quarter of the 19th century."(12) Reading this sentence, one might assume that only a few isolated troglodyte pseudoscientists would still be living under the outworn and discredited misconception that oil can be formed from biological materials. However, in fact universities and oil companies are staffed with thousands of "competent physicists, chemists, chemical engineers and men [and women!] knowledgeable of thermodynamics" who not only subscribe to the biogenic theory, but use it every day as the basis for successful oil exploration. And laboratory experiments have shown repeatedly that petroleum is in fact produced from organic matter under the conditions to which it is assumed to have been subjected over geological time. The situation is actually the reverse of the one Kenny implies: most geologists assume that the Russian abiotic oil hypothesis, which dates to the era prior to the advent of modern plate tectonics theory, is an anachronism. Tectonic movements are now known to be able to radically reshuffle rock strata, leaving younger sedimentary oil- or gas-bearing rock beneath basement rock, leading in some cases to the appearance that oil has its source in Precambrian crystalline basement, when this is not actually the case.
Geologists trace the source of the carbon in hydrocarbons through analysis of its isotopic balance. Natural carbon is nearly all isotope 12, with 1.11 percent being isotope 13. Organic material, however, usually contains less C-13, because photosynthesis in plants preferentially selects C-12 over C-13. Oil and natural gas typically show a C-12 to C-13 ratio similar to that of the biological materials from which they are assumed to have originated. The C-12 to C-13 ratio is a generally observed property of petroleum and is predicted by the biotic theory; it is not merely an occasional aberration. (13)
In addition, oil typically contains biomarkers - porphyrins, isoprenoids, pristane, phytane, cholestane, terpines, and clorins - which are related to biochemicals such as chlorophyll and hemoglobin. The chemical fingerprint of oil assumed to have been formed from, for example, algae is different from that of oil formed from plankton. Thus geochemists can (and routinely do) use biomarkers to trace oil samples to specific source rocks.
Abiotic theorists hypothesize that oil picks up its chemical biomarkers through contamination from bacteria living deep in the Earth's crust (Gold's "deep, hot biosphere") or from other buried bio-remnants. However, the observed correspondences between biomarkers and source materials are not haphazard, but instead systematic and predictable on the basis of the biotic theory. For example, biomarkers in source rock can be linked with the depositional environment; that is, source rocks with biomarkers characteristic of land plants are found only in terrestrial and shallow marine sediments, while petroleum biomarkers associated with marine organisms are found only in marine sediments.
