Is the K-T Boundary Layer a Coal Seam?
This may seem unusual but what I am proposing is a non-catastrophic explanation for a supposed catastrophic geological feature- the K-T Boundary Layer.
The idea that a titanic meteorite impact occurred some 65 million years ago removing the dinosaurs and thus paving the way for the subsequent evolution of mammals and eventually humans has, over the last 35 years gained popularity amongst lay and scientific people alike.
So exciting is the idea that the media and Hollywood have soaked it up and seemingly every dinosaur documentary or movie must have a dramatic computer generated, special effects impact scene.
The meteorite impact theory is but one in a long line of theories some catastrophic, some not, that brings an end to the reign of the dinosaurs and other life forms at the end of the Cretaceous Period some 65 million years ago. The idea, in its latest form, was developed by Professors Luis and Walter Alvarez and dates back to 1979. In an effort to measure how long it had taken for a thin layer of clay at the K-T boundary (this is the geological layer dividing the Cretaceous Period from the Tertiary Era) to be deposited, the Alvarez team opted to use concentrations of the element iridium, which is relatively rare at the Earth’s surface, as a benchmark. It was subsequently found that the clay contained unusually high concentrations of the metal. To account for this anomaly the team initially suggested that a nearby supernova was the cause but later this was changed to a meteorite impact when other suspected supernova products were not found. Subsequent samples, taken later, from 50 to 80 sites around the globe also displayed the iridium concentration.
An early challenge to the theory was proposed. The iridium, critics said, could have come from volcanic eruptions, which are known to bring iridium up from deep within the Earth.
However, in the mid 1980’s chemists Jeffrey Bada and Nancy Lee at the Scripps Research Institute in California found traces of the amino acid, alpha-aminoisobutyric acid, in the K-T layer. This amino acid is virtually non-existent on Earth and led to suggestions that the meteorite was of a type known as a carbonaceous chondrite; amino acids and other organic (carbon based) compounds are found in abundant quantities in such objects. More recently a rare isotope of helium- He3- has been found, in steady quantities, in rocks spanning the K-T layer. Again, according to Sujoy Mukhopadhyay of the California Institute of Technology, this finding rules out volcanism and confirms that a meteorite was responsible.
Carbon is also associated with the K-T layer, impact enthusiasts refer to this carbon as the ‘fireball’ layer formed when vegetation caught fire following the impact, roasting some of the dinosaurs alive while others perished in the ‘nuclear winter’ that followed as the earth was blanketed in a thick smog.
The same chain of reasoning has been applied to other mass extinction events including the late Permian period extinction some 251 million years ago. In recent years, carbon molecules, helium and argon were found in rocks from this period. Researchers at the University of Washington State in Seattle suggested that they were evidence of an impact event but this time due to a lack of iridium in the rocks, a comet was suggested as the cause.
Already we can see a pattern emerging. Carbon, amino acids or bio- molecules, helium isotopes, iridium or other rare earth elements, occurring globally, concentrated in some areas and strata but not others, can a terrestrial process account for these observations?
A theory does exist and it describes in detail a process that can account for the features seen globally in the K-T boundary layer and other strata. That theory is the Deep Earth Gas theory, proposed by the late Professor Thomas Gold of Cornell University, in 1977.
(Note: The Anhydride Theory by C. Warren Hunt also claims an abiogenic origin for natural gas, petroleum and coal but places a bigger role on bacteria living deep in the Earth’s crust during the formation of hydrocarbon deposits. In the years shortly before Gold’s death, Hunt and a number of scientists claimed Gold had plagiarised their theories and claimed them as his own; although Gold had acknowledged the work of pioneering scientists in this field in his 1993 USGS paper ‘The Origin of Methane (and Oil) in the Crust of the Earth’ and most of the elements of Gold’s theory were in place long before the alleged plagiarising took place).
The theory offers an alternative explanation as to the origin of ‘fossil fuels’. That idea in itself is not new, as long ago as the 1870’s the Russian chemist Dmitry Mendeleev, who formulated the periodic table of the elements, was among the first to suggest a non- biological origin of the earth’s hydrocarbons. In the 1960’s the chemist Sir Robert Robinson commented “It cannot be too strongly emphasised that petroleum does not present the composition picture expected from modified biogenic products, and all the arguments from the constituents of ancient oils fit equally well, or better, with the conception of a primordial hydrocarbon mixture to which bio-products have been added.”
According to the theory the hydrocarbons which result in the formation of natural gas (methane), crude oil and coal deposits originate deep (100-300km) within the Earth’s mantle. Vast quantities of such volatiles exist at such depths, they are among the primordial constituents from which the Earth formed and for the last 4,000 million years of Earth’s history (conventional dating) have been slowly migrating, or upwelling, toward the surface. Evidence that primordial volatiles still exist at great depth within the mantle has been confirmed with the discovery of elevated levels of the light isotope of xenon (an inert gas) in deep wells in the U.S. and Australia.
The theory can explain some puzzling features associated with the accepted view, it accounts for petroleum’s association with helium. Helium-He3- is welling up from even deeper levels in the mantle as it does so it encounters hydrocarbons from shallower levels and continues to the surface with them- forming concentrations where the hydrocarbons settle. It can account for the phenomenon of oil-field recharging, hydrocarbons continue to upwell in vast quantities today. It also accounts for the fact that high levels of iridium are found in oil wells. Migrating hydrocarbon fluids leach metals, present in trace quantities, from the surrounding rocks transporting them to the surface strata.
As hydrocarbons approach the surface they experience a sequential loss of hydrogen. As Gold writes: ‘Vast methane deposits at the greatest depth, lighter oils higher up and the heaviest oils on top (though each pocket may be capped with some amount of methane). In some fields, the most carbon-rich and top most hydrocarbon is not crude oil; crude oil is not always the end of the sequence. Rather, above the oil layers may be black coal. The blacker the coal, the greater the loss of hydrogen and the greater the resulting carbon-to-hydrogen ratio.’
But what of the bio molecules found in ‘fossil fuels’? Here, in 1992 Professor Gold introduced a new idea one hinted at in Robert Robinson’s words. Called the Deep Hot Biosphere it states that the porous rocks of the earth’s crust are populated by primitive hyperthermophilic archaebacteria, down to a depth of perhaps 10km, it is traces of these bacterial communities that provide the biological content of primordial hydrocarbons. It is interesting to note that although coal and crude oil are supposedly reworked ferns and algae, bacteria exclusively use the high carbon number molecules found in both hydrocarbons.
A typical K-T section is capped by a layer of carbon, impact enthusiasts call this layer ‘soot’ which supposedly formed from burning vegetation around the globe but in some areas - for example New Mexico- the layer of ‘soot’ is sufficiently thick enough to be recognised as a coal seam (recall that coal is often the end result for ascending hydrocarbons).
But what of the occurrences of amino acids in the K-T layering?
As we have seen within the Earth’s crust there exists an immense population of primitive hyperthermophilic archaebacteria thriving on an abundant supply of primeval hydrocarbons. Is it any coincidence then that the amino acid isolated by Bada and Lee is also found in two rare types of bacteria?
Studies of K-T boundary clay mineralogy from samples at four different localities found ‘the boundary clay is neither mineralogically exotic nor distinct from locally derived clays above and below the boundary. The significant ejecta component in the clay that is predicted by the asteroid-impact scenario was not detected.’
The validity of the impact theory relies on the presence of carbon and iridium as there is no mineralogical boundary. However, all the ingredients are present to explain the features seen at the K-T boundary; primordial Helium from deep within the mantle; carbon- the final stage for upwelling hydrocarbons; amino acids- traces of a bacterial ecosystem deep within the Earth and iridium- leached and transported to the surface by the very same upwelling hydrocarbons. The layering at the K-T boundary is due to upwelling hydrocarbons, it has all the hallmarks of a mini coal seam. No extra-terrestrial influences are required to account for its origin.
The deposition of hydrocarbons in Earth’s surface rocks is an on-going process and in view of this the features found at the K-T boundary are probably fairly recent- geologically speaking (some sources suggest an age of 1,240 years old for some oil deposits, I suspect some deposits are MUCH younger). But what of the billions of animal and plant remains found in the Phanerozoic rock record? These remains are testament to a global cataclysm far larger than scientists (or a Hollywood special effects department) currently dare to imagine.
1. Gold. T. 1999. The Deep Hot Biosphere. Springer-Verlag New York Inc.
2. Rampino. M.R and Reynolds. R.C. 1983. Science vol. 219, p495
3. Bada. J and Lee. N. 1986. Science Digest. May 1986 p30- 31
4. Hecht. J. 1991. New Scientist. April 6 1991, p19
5. Caffee. M. 1999. Science vol. 285, p2115
6. Becker. L. 2001. Science vol. 291, p1530
7. Mukhopadhyay. S. 2001. Science vol. 291, p1952