Total Pageviews

Tuesday, 24 January 2012

The Deep Hot Biosphere

The Deep Hot Biosphere

   The Deep Hot Biosphere theory was proposed by the scientist astrophysicist, astronomer and cosmologist  Thomas Gold (1920-2004). It concerns of a microbial biosphere that exists at depth, profuse both within the Earth and probably other planets, feed by primordial and abiotic hydrocarbons, mainly methane and chemical energy. This realm, dominated by procaryotic Archaea and  positioned on suitable range of temperature, is independent of surface life and protected of harmful radiation and meteoritic impacts. The biomass of deep biosphere may exceed the entire mass of the surface biosphere. Deep levels in the Earth would be an environment that could form catalytic and autocatalytic molecules that contribute for the emergence of life. After, this deep primeval life developed a sophisticated apparatus to conquest the surface of planet - by photosynthesis - using energy from sunlight to dissociated water and carbon dioxide to produce carbohydrates, permitting autotrophy.

   The Deep Hot Biosphere was originally published in an article of PNAS (Proceedings of the National Academy of Sciences,1992, USA). In 1999, Thomas Gold published the book "The Deep Hot Biosphere - The Myth Of Fossil Fuels" which describes in detail the ideas that support this theory. The main reason consists in understanding the origin of hydrocarbons whose base is in Deep-Earth Gas Theory.

   Thomas Gold postulated that hydrocarbons (such as oil, natural gas and black coal ) are primary compounds, i.e., were incorporated into the Earth during the process of planetary accretion. He stated that hydrocarbons are surelly abiotic compounds and very common on Earth and the universe. His ideas and from other eminent scientists about the origin of oil and natural gas are extensively discussed and offer outstanding solutions to solve the petroleum paradox.

   His work is a legacy to science and humanity and the book The Deep Hot Biosphere - The Myth Of Fossil Fuels is also accessible to understanding by laymen. In summary his ideas can thus be defined as its own quote:

"Hydrocarbons are not biology reworked by geology (as traditional view would hold), but rather geology reworked by biology"

Gold, T., 1992
Proc. Natl. Acad. Sci, USA
Vol 89, pp. 6045-6049, July 1992

There are strong indications that microbial life is widespread at depth in the crust of the Earth, just as such life has been identified in numerous ocean vents. This life is not dependent on solar energy and photosynthesis for its primary energy supply, and it is essentially independent of the surface circumstances. Its energy supply comes from chemical sources, due to fluids that migrate upward from deeper levels in the Earth. In mass and volume it may be comparable with all surface life. Such microbial life may account for the presence of biological molecules in all carbonaceous materials in the outer crust, and the inference that these materials must have derived from biological deposits accumulated at the surface is therefore not necessarily valid. Subsurface life may be widespread among the planetary bodies of our solar system, since many of them have equally suitable conditions below, while having totally inhospitable surfaces. One may even speculate that such life may be widely disseminated in the universe, since planetary type bodies with similar subsurface conditions may be common as solitary objects in space, as well as in other solar-type systems.

Sunday, 22 January 2012

Turbidite Sequences

Turbidite Sequences

   Turbidites are syntectonic sedimentary deposits orginated by deep submarine turbidity currents, especially in foreland basins, in tectonic setting of convergent margin (active). To most part of geologists, turbidite is a sequence of layers that consist of a grano-classified set of sandstone strata/pelitic sediments, generally in fining-upward that were deposited by turbidity currents and is commonly covered by hemipelagic pelites containing assemblages of  deep-water fossils.

   The deposits are formed by concentrated hyperpicnal flow, building a succession of  sandy and hemipelagic sediments very thick set of sedimentary strata (layes), deposited in a short period of geologic time. They are linked to the rising of orogenic chains, exposing the crystalline basement, intense denudation through small rivers that lead quickly (in terms of geological time) with large amounts of sediment deposition in a confined environment, in the context of deep water, forming typical sedimentary structures. The composition of turbidite sequences may be siliciclastic (sands, pelites), carbonates, lithic fragments, salt, volcaniclastics and others.

   The turbidites are characterized by layers (bed) with great lateral continuity, bedding regularly and generally gradational with thinning of the grains to the top of each stratum (layer), ripple marks, association of hemipelagic sediments, base-layer structures as sole marks, flutecasts, marks objects (toolmarks, grooves). Each stratum of turbidite (bed) is deposited in a single one event (flow). The partition of energy between dense and turbulent flow during a turbidity event gives the typical features of these deposits.  In Bi-partite flows dense and fast deposition commonly form massive sandstones while turbulent flow will deposit fine sediments (pelites).The deceleration of the turbulent flow may form ripple marks before decanting the less dense materials and the finer particles, such as clays and silts.

The characterization of some facies and processes associated with siliciclastic turbidites comes primarily from the observation of the structures formed in the ignimbrite flows, which are volcaniclastic rocks.

Spetacular turbidite outcrop. Gorgoglione Flysch, Miocene, South Italy

Classical turbidite deposits with high efficiency flux occur in the European foreland basins, with the best expositions in the Apennines of Italy, Spanish  Pyrenees, Western Alps in France. In Brazil, State of Santa Catarina, typical turbidites occur in Early Paleozoic Itajai Basin and in some Proterozoic basins.

   The turbidite sequences are highly sought by petroleum geologists because they can constitute good reservoirs for hydrocarbons (oil and natural gas).

   Among the scholars of the turbidite sequences are Carlo Migliorini, Kuenen, Arnold Bouma, Emiliano Mutti, Franco Ricci-Lucchi, Shanmugan, Mulder, Pickering, Normark, Lowe, Middleton, P. Heller, Kneller, R. Tinterri and many others.

   But what would be the unconventional ideas on the issue of use of the term turbidite? The issue is the problem caused by the confusion that is made to designate and generalize as turbidites all sedimentary sequences deposited in the context of deep water, especially those that occur in divergent margins (passive margins). Deep-water deposits in divergent margin could not be designated as turbidites because they are related to flows of low efficiency (energy), mainly linked to the response of sea level oscillation, frequently in Lowstand System Tract. The big rivers carry sediments during flood events, but if the sea level remains stable, these sediments are not transported beyond the slope and remain, whether in bars or as mouth-bars of the rivers, in deltaic deposits, dominated by rivers, waves or tides. Part of these sediments can reach regions offshore platform, but the transfer of large amounts of sediment can only be transported by catastrophic event with significant fall of sea level. In this context, strong erosion occur in the onshore basin drainage (watershed) and forming incised valleys in environments of near-shore and platform (shelf), developing of deep cut canyons on the slope that will facilitate transport beyond the slope of those materials present on the platform, and its final deposition at basin floor. In some areas, deep-water bottom-currents may rework slightly the top of turbidite sediments and form contourite deposits. However, even all these process does not have high efficiency to form the typical features of classic turbidites present in foreland basins. Thus it seems desirable to use the term turbidite only for deposits with typical sedimentary facies and its association such as those occurring in the foreland basins, with deposition associated to deep confined environments, source and transport of sediments due high rising of mountain chain and small dirty-rivers. In any case, much remains to be understood about the processes that form turbidite sequences.

Zumaia is a small village along the coast of Guipúzcoa (Basque Country). Famous in this area is known as the geological formation Flysch Zumaia. These impressive outcrops, often with verticalized layers and extraordinary continuity, ranging from Late Cretaceous to Paleogene. This alternation of calcareous clay and marl are a classic example of Flysch, i.e. classical turbidite sediments.

Peat Formation

Peat Formation

   According to the scientist Thomas Gold, in his book "The Deep Hot Biosphere", peat and lignite are clearly biological materials,  but the reason for their accumulation may well lie in the circumstances created by non-biological hydrocarbons that happen to upwell from below and that may also add more carbon than contained in the plants involved.

   Peat and lignite also represent a most interesting partnership between biogenic and abiogenic carbon sources. The anoxic situation in the swamp may often be due to the rapid growth of bacteria plundering any available oxygen atoms in order to burn, for their metabolic needs, abiogenic methane upwelling from below. Because methane is such a desirable food, methanotrophic microbes will outcompete those tha would otherwise use oxygen to attack the plant debris, the cellulose and lignin molecules of which many may be particularly resistant to attack. A swamp will then be created from all the plant material that has accumulated and not yet decomposed.

   It's also interesting that where a patch of peaty terrain in Switzerland are vegetated by the same flora that is characteristic of peat bogs that occurs on steep hillsides, along fault lines that run transverse to the slope hill.  Methane outgassing is therefore likely to create peat and lignite deposits in regions overlying a strong flow of hydrocarbons.

  Element mercury sometimes occur at trace content associated to peat. Some researchers report this evidence, meanwhile they used to link the presence of mercury due to anthropic cause, i.e. industrial pollution and for the old peat they link to the epoch of Industrial Revolution, which is nonsense. Mercury is related to gaseous abiogenic hydrocarbon upwelling, mainly dimethyl-mercury as also occur in coal deposits by the same process.

   Certain kinds of continental sponges as Family of Porifera Metaniidae may also associate with altitude peat along fault lines or lagoons. Methane outgassing is frequently measured over these places.

Saturday, 21 January 2012

Origin of black coal

Origin of Black Coal

     Many people think that the process of coal formation is fully understood. The paradigm is that coal is essentially a product formed through the burial of plants and, according to this conventional view, the common presence of plant fossils associated with coal deposits therefore would explain intrinsically throught biogenic origin. However, there are much evidences related to the coal origin that are not yet understood.

     The American scientist Thomas Gold proposed in his book "The Deep Hot Biosphere" an insight into the processes of coal formation very different from the conventional view. He states that the existence of fossils with an excellent state of preservation, including textures at the cellular tissues level, proves that coal can not be formed through biogenic origin.

He said in an interview:

“The coal we dig is hard, brittle stuff [but] it was once a liquid, because we find embedded in the middle of a six-foot seam of coal such things as a delicate wing of some animal or a leaf of a plant. They are undestroyed, absolutely preserved, with every cell in that fossil filled with exactly the same coal as all the coal on the outside... The fact that coal contains fossils does not prove that it is a fossil fuel; it proves exactly the opposite. Those fossils you find in coal prove that coal is not made from those fossils. How could you take a forest and much it all up so that it is a completely featureless big black substance and then find one leaf in it that is perfectly preserved? That is absolute nonsense.”

 Highly preserved plant fossil in black coal

    The abiogenic theory then, combined with the deep, hot biosphere theory is as Gold succinctly phrases it; “not biology that has been reworked by geology but geology that has been reworked by biology”.  One might expect coal to be the exception; surely coal is the result of degraded plant life and ancient swamps. No, says Gold, but he does make a partial exception for peat and lignite, which are indeed reworked plant life with some help from primordial hydrocarbons. But black coals come from the same upwelling of hydrocarbons as petroleum and methane, originating far below the sedimentary layers. The process is essentially a sequential loss of hydrogen atoms as hydrocarbons upwell through porous rock, and this is the primary reason why so many petroleum fields are configured in a “layer-cake” manner. Methane is at the lowest depth, layered on this is light crude, next come the heavier oils, and then often on top of all is blackcoal. This correlation of coal with petroleum fields can be seen in many parts of the world (see pictures of US oil and coal maps below). The blacker the coal the greater the hydrogen loss and the greater the carbon to hydrogen ratio. How do the hydrocarbons lose their hydrogen atoms? Though many factors are involved, and we can go no further into the technical details here, there is a gradual process of oxidation as the hydrocarbons upwell, and carbon deposits left behind tend to be a catalyst for more carbon deposits, not unlike what happens in an internal combustion engine.

Coal formation

Biogenic (Orthodox): Coal is a material derived from organic detritus (plant material) that was buried and compressed. 

 Coal mining in Indonesia

Abiogenic: Coal (black only) is a material that may contain the presence of organic compounds, but that was filled by inorganic hydrocarbons that migrated by continuous upwelling come from great depth and reached these deposits in the surface and preserving fine debris and cellular tissues of plants. Such a situation may occur in the surface migration of methane and oil on areas of marshes or peat.
Several metals such as Nickel, Vanadium, Chromium, Cadmium, Mercury, Arsenic, Lead, Selenium, among others, are also present in coal. Many coals are sometimes bituminous and also have high sulfur content. As with oil, these metals come from deep inside the Earth (mantle) and black coal only represent stages in high loss of hydrogen of primordial hydrocarbons and intense biodegradation at shallower levels as postulated by Thomas Gold.
It's interesting that the same biomarkers found in oil are present in coal and represent, of course, parts of prokaryotic archaea that re-worked primordial hydrocarbons.
It's not rare association of uranium with black coal deposits. Association of biocide and poisonous element mercury with coal is also common evidence. In many coal deposits in the world are commonly found thin white layers called tonsteins that consisting of kaolin material, sometimes interpreted as volcanic ash.
There are some occurrences of coal in Precambrian, Neoproterozoic. According to fossil record of planet Earth there's no superior plant  at that time, then the Proterozoic coal is surely abiotic and represents probably  ancient oil accumulation with high hydrogen loss and biodegradation of primordial hydrocarbons.
Coal sometimes occurs in thick layers, as shown in the pictures below. It would be hard to imagine a swamp or anarea with thick ancient forests accumulated and its volume decreased after the water loss and compaction of the layers to form a thick coal layer.
Only the brown coal (lignite) should be considered dominantly biogenic.

Coal layer over 100 ft - Powder River, Wyoming, USA

Thick coal layer. See car and person as scale

   It is also common association of coal over oil and gas production areas. See below a comparison between maps of oil and coal occurrences in the United States.

Oil and natural gas production areas in the United States

   Main coal basins in the United States

"Petroleum and coal were made from materials in which heavy hydrocarbons were common components. We know that because the meteorites are the sort of debris left over from the formations of the planets and those contain carbon in unoxidized form as hydrocarbons as oil and coal-like particles. We find that in one large class of meteorites and we find that equally on many of the other planetary bodies in the solar system. So it’s pretty clear that when the Earth formed it contained a lot of carbon material built into it." (Thomas Gold)