Ancient Oil Sleuths Track Tectonic Twists and Turns

Rivers of the Modern World
Most crude oil comes from ancient marine organisms which bloomed, died, sank, and were covered by sediment to transform under conditions of heat and pressure into petroleum. The organisms required sunshine, CO2, and nutrients -- plus sedimentary cover. These conditions were best met in tropical seas which received nutrient-rich outflows from either rivers or rich sea currents and upwellings.

But rivers supply both nutrients and sediment, so it makes sense to look to areas which were offshore from ancient river deltas. Above, you can see the main rivers of the modern world.

ImageSource
But the continents of the Earth were not always in their current relationship to each other. 250 mya the continents were situated close together in a formation now referred to as Pangaea. The geology of the landmasses of that time were somewhat different, meaning that different rivers flowed into different seas.

This movement of the continents in relation to each other is caused by plate tectonics, a dynamic phenomenon which is largely controlled by actions at the bottom of the seas.

The graphic above is meant to illustrate possible sites for "abiotic oil" deposits, but if you look carefully at the oceans, you can find seafloor ridges which are ground zero for the motion of the continents. New seafloor -- as molten lava which cools and solidifies in contact with seawater -- is pushed upward from beneath the ocean crust, causing a spreading of the ocean crust outward. Eventually the ocean crust is pushed into contact with thicker continental crust, where it subducts -- dives downward into the mantle. This subduction is associated with volcano formation, and other geologic changes, such as slow movement of the continental plates.

ImageSource
This "dance of the continents" is likely to bring the land masses together again in the future, over and over again in different formations. This is important in relation to where very old oil deposits are likely to be found, and where large future deposits of oil are likely to be formed in their turn.

For example, why is oil often found in deserts and arctic wastes?

Oil and gas result mostly from the rapid burial of dead microorganisms in environments where oxygen is so scarce that they do not decompose. This lack of oxygen enables them to maintain their hydrogen-carbon bonds, a necessary ingredient for the production of oil and gas. Newly developing ocean basins, formed by plate tectonics and continental rifting, provide just the right conditions for rapid burial in anoxic waters. Rivers rapidly fill these basins with sediments carrying abundant organic remains. Because the basins have constricted water circulation, they also have lower oxygen levels than the open ocean. For instance, the Gulf of California, an ocean basin in development, is making new oil and gas in real time today. The Gulf of Mexico is also a great example of new oil and gas formation in a restricted circulation environment (see image at right above).

The same plate tectonics that provides the locations and conditions for anoxic burial is also responsible for the geologic paths that these sedimentary basins subsequently take. Continental drift, subduction and collision with other continents provide the movement from swamps, river deltas and mild climates--where most organics are deposited--to the poles and deserts, where they have ended up today by coincidence. In fact, the Libyan Sahara Desert contains unmistakable glacial scars and Antarctica has extensive coal deposits--and very likely abundant oil and gas--that establish that their plates were once at the other ends of the earth (see image at right). _SciAm

Similar detective work may lead prospectors to rich petroleum deposits lying between Norway, Iceland, and Greenland. By the same logic applied to more recent timelines, oil and gas in the South China Sea is likely to be discovered.

As the SciAm article above explains, when a river flows into a limited basin -- such as the Gulf of Mexico -- oil and gas formation are most likely to occur due to rapid sedimentation. But thanks to plate tectonics and shifting continents and river-beds, many areas where rivers once flowed into limited basins have become something completely different, today.

It is no challenge to find oil where crude is already seeping to the surface. That was the case in the early days of oil discovery in the US, the Persian Gulf, and Central Asia. But to find the oil of ancient seas -- that is a challenge. Particularly since that is where most of the world's oil awaits.

Taken from a recent article at Al Fin the Next Level

The Earth is floating on a sea of hydrocarbons. We are approaching a time when we will be able to "recycle" the carbon we consume, into yet more hydrocarbons and high value chemicals. For more invormation on such trends, be sure to follow the Al Fin Energy blog.

Massive Amounts of Water Entrained Into Earth's Mantle

SD
As oceanic crustal plates grow and butt against continental plates, they subduct under the continental plates. As they dive into the Earth's mantle for "re-cycling", these ocean crusts carry large quantities of water and sediment with them. Geologists are learning more about what happens to the subducted water.

Scientists know: many volcanoes need water for their eruption. In the upper mantle, water lowers the melting temperature of the rocks. As a consequence, it melts faster and can ascend in form of magma to the Earth's surface. In areas where an oceanic plate is pushed underneath a continent by plate tectonics processes, large quantities of water reach the interior of the Earth.

Such a region, called subduction zone, can be found at the west coast of Latin and South America. Through large cracks formed during the subduction process of the oceanic plates water penetrates, is partly captured and transported in the mantle. There, high pressure and temperatures squeeze it out of the subducting plate and the water ascends back to the surface. On the way back it supports the formation of magma. Therefore all subduction zones are characterized by volcanoes at the continental margin.

"So far we knew that the entrainment of water into the Earth's mantle in the area of subductions zones is substantial and that it is released again by volcanic process. Nevertheless, the exact path of the water down to the mantle and back to the surface had so far not been shown in one unifying context," explains Tamara Worzewski, geophysicist in the Collaborative Research Centre (SFB) 574 "Fluids and Volatiles in Subduction Zones -- Climate Feedback and Trigger Mechanisms for Natural Hazards" who has investigated these processes. Together with Dr. Marion Jegen and Prof. Dr. Heidrun Kopp from the Leibniz Institute of Marine Sciences at the Christian-Albrechts-Universität (IFM-GEOMAR) in Kiel and colleagues Dr. Heinrich Brasse from the Freie Universität Berlin and Dr. Waldo Taylor from Costa Rica, she was able to show for the first time the complete water path from the seafloor down to 120 kilometre depth and back to the surface using electromagnetic methods.

The study, now published in Nature Geoscience, is also part of Worzewskis PhD Study. _SD

PBSRegular readers of Al Fin and Al Fin Energy will be aware of these blogs' interest in hydrocarbons that find themselves inside the Earth's mantle. But the fate of water in the mantle can be closely tied to the fate of much of the organic carbon which finds its way into the mantle by the same subductive process. Volcanic eruptions clear a great deal of both water and carbon from the mantle, along with other gaseous and mineral matter. It is part of the ongoing geologic cycles of the planet.

And yet, massive amounts of crustal organic carbon and mantle hydrocarbons persist long enough to migrate and transform into potentially economic reserves of "fossil fuels." Most of this resource will remain unkown to humans, despite a great deal of it settling within the growing technological and economic reach of humans.

We have barely begun to learn the basics about our planet, our climate, our solar system, our portion of the spiral arm of the Milky Way Galaxy, and so on. How absurd it is that pseudoscientific quasi-religions such as catastrophic anthropogenic global warming orthodoxy, or peak oil DOOM!, should find such large, gullible, and enthusiastic followings.

Massive Dieoff of Algae 250 MYA: Poisonous Upheaval at PT Junction

Physorg
At the junction of the Permian and Triassic periods around 250 million years ago, the algae of the world appear to have been killed off by massive amounts of hydrogen sulfide. Massive volcanic activity triggered an enormous release of toxic gases as well as large quantities of CO2. The ocean's ecosystems were overturned, as only 1 in 10 ocean species survived. Massive quantities of dead algae, animals, and vegetation descended onto a dark and suddenly anaerobic seafloor, and were buried by large masses of ash and other sediment. In other words, a perfect environment for the formation of oil and other hydrocarbons. So, what happened to them?

The mass extinction at the end of the Permian period almost cleared the planet of life 250 million years ago. Only one in ten species in the ocean survived. Two-thirds of reptiles and amphibians disappeared. Even plants and insects suffered major losses. But in this near-perfect strike, the first "pin" to topple may have been algae, according to researchers studying molecular fossils from this time.

The Permian-Triassic, or P-T, extinction event happened long before dinosaurs had even appeared on the scene. Often called the Great Dying, it was the most dramatic pruning of the tree of life that we have on record. "It was not only the largest, but also the most enigmatic mass extinction of all time," says Roger Summons from MIT.

Unlike the dinosaur die-off, there's no credible evidence of an asteroid impact to blame for the P-T extinction. Instead, scientists have been forced to sort through a number of factors: The formation of the supercontinent Pangaea reduced shallow marine habitats; slower ocean circulation deprived the deep ocean of oxygen; and one of the largest volcanic eruptions in history caused a spike in carbon dioxide that would have greatly warmed the planet.
On top of all that, hydrogen sulfide – a lethal gas that smells of rotten eggs – may have poisoned the ocean and the atmosphere. Summons and his colleagues are leading proponents of this theory, having discovered molecular evidence for a substantial proliferation of bacteria that rely on hydrogen sulfide for their metabolism. _Physorg

More fascinating detail at the link above.

The Earth is about 4.5 billion years old. Photosynthetic organisms have been converting sunlight, CO2, and water into carbohydrates and lipids for about 3.5 billion years. And yet, most of the oil and gas that humans have accessed, originated roughly 200 million years or fewer ago.

Certainly CO2 levels were far higher in earlier periods of geologic history. Uncountable numbers of photosynthetic organisms lived and died to make and keep the planet's atmosphere oxygen rich and CO2 poor (currently 0.04% of atmosphere is CO2 vs over 20% O2).

It is highly likely that other less prominent dieoffs, accompanied by massive volcanism, occurred throughout the long geologic history of the planet. Each time CO2 concentrations shot up, Earth's photosynthetic arsenal massed itself to meet the challenge, and restore the oxygen heavy balance of the planet's gases.

Over and over again, massive volumes of plankton and vegetation were buried in deep anaerobic conditions, leading to unimaginable volumes of hydrocarbon generation. And almost all of that occurring in parts and depths of the Earth's crust which humans have not yet explored with any care.

Reporting in the journal Nature, scientists from Royal Holloway, University of London and the Institut de Ciencies del Mar (Spanish Research Council) have revealed a new model that explains how continents thin as well as helping to more accurately predict the location of hydrocarbons such as oil and gas. _SD

via New Energy and Fuel
A new model of continental thinning, faulting, and re-forming, promises to provide new ways to locate vast new petroleum reserves. Scientists at institutions in the UK and Spain hopes to provide petroleum prospectors with new conceptual tools for determining the most likely areas to find the billions of years worth of hidden hydrocarbons.

The new model is based on high-resolution images of the tectonic structure of the crust at such margins. These images are obtained using elaborate seismic methods, which give a picture of the crust below the oceans, showing where faults and sediments are.

The new model has important implications for the formation of hydrocarbon resources, plus it offer a new view of the style of faulting during continental thinning, sediment deposition and potentially for the opening of oceanic gateways and oceanic circulation. _BrianWestenhaus

The geologic sciences are still quite young, sharpening their teeth on ideas that take into account the antiquity of the planet, the incessant nature of geologic processes, and of microbial and photosynthetic organisms which have thrust their way into the midst of epochal geologic upheaval.

Older geologic theories focused upon easily accessible sediments from relatively recent geologic regions -- areas laid down millions or dozens of millions of years ago as opposed to the billions of years that photosynthesis has been converting CO2 to organic carbon. Exceptions to conventional theory have popped up from time to time, but have been largely ignored as anomalous.

As large international companies get shut out of the richest oil reserves of OPEC nations and corrupt, unreliable nations such as Russia, they are forced to look for oil wherever it may be found. Continental shelves off large rivers such as the Mississippi and the Amazon are likely places for grabbing oil dozens of millions of years old. But to find the truly old oil and hydrocarbon, some new ideas will be necessary -- and will require testing. All of that takes time, which the big international oil companies are running out of, caught between political peak oil (Obama, Boxer, Salazar, etc.) and sovereign oil companies that nationalise the valuable assets and work of multi-nationals at the least opportunity.

Why the Age of Oil Is Just Beginning & Why It May Soon End

Petroleum is thought to have originated mainly from the remains of sediments of photosynthetic organisms which sedimented from ancient seas, and were heated and compressed by geological processes. Assuming that to be true, it is interesting to note that photosynthetic organisms originated almost 3.5 billion years ago. From the chart above, one can note that the Oxygen concentration of Earth's atmosphere rose markedly at about the same time as the origin of cyanobacteria (2.8 gya), eukaryotes (2 gya), and algae (1 gya), respectively.

The higher the oxygen level the higher the rate of sedimentation of photosynthetic organisms, presumably. Note that such sedimentation began to occur nearly 3 gya. Also note that the vast majority of petroleum which humans have begun to tap into, originated roughly 100 mya or more recently. I think you will agree with me that the Proterozoic Era (2.5 gya to about 540 gya) is likely to have been extremely prolific in the sense of laying down organic carbon in sediments.

Now, observe the Tethys Sea in the image (see Tethys Ocean). The Tethys Sea (Ocean) opened about 250 mya and closed about 10 mya. Most of the modern world's known oil and gas reserves lie in the sediments which once underlay the Tethys water masses. Much of this oil and gas is of fairly recent origin, geologically speaking, although some dates back to the early Triassic (250 to 200 mya). It only takes a hundred thousand years or so to make petroleum by natural means, depending upon local geology.

Now, I know you are saying to your computers, "But Al, if we are only beginning to tap a very small fraction of all the oil that has been deposited, where is all the rest of the oil?"

To which I reply, "Where do you think it is? Floating beyond the orbit of Pluto?" No, seriously, a lot of things can happen to oil deposits over time. Some can seep into oceans and be eaten by microbes. Some can be turned into various types of gas, and escape or be adsorbed by minerals. But most of it is likely to have been buried in the constant geologic upheaval of the planet's layers of rock.

The Japanese and Chinese have recently begun finding significant deposits of oil and gas within volcanic rock. Oil geologists are beginning to look beneath undersea volcanic deposits for submerged oil fields of great potential. The Russians have been finding significant petroleum beneath deep igneous and metamorphic layers for many years. The history of oil formation goes back over ten times farther than almost all of the oil humans have retrieved or located so far -- although drops of bitumen has been found in rocks dated between 2.6 and 3.2 gya.

Australian expert in petroleum geology, Associate Professor Colin Ward of the University of New South Wales, says it's not surprising that algae and other simple life forms existed during this early stage of the Earth's history.

What is significant, is that there are now signs they were producing oil.

"He's found good evidence that the processes that generate oil were active in a very early history," he says.

Rasmussen's discovery may have implications for exploration, Ward says.

"It focuses attention back on very old rocks as a possible places to look for more oil and gases," he says. _Source

So why do I say that the age of oil may be ending soon? Because while it takes 100,000 years (plus or minus) to make petroleum by natural processes, it only takes a matter of weeks -- from start of algae crop to harvesting and processing -- using modern methods. Yes, modern oil made this way is very expensive, but that is because we have just begun learning to create it. Within 20 years, Al Fin energy experts assure me that microbial fuels and energy will be fully price-competitive with petroleum, and rapidly scaling to match production within 30 years.

You may hear a lot of talk about "peak oil" in certain circles. The most likely kinds of peak oil you will see are "political peak oil" from bad energy policy or political conflict, and "peak demand" -- when consumers choose other forms of energy and fuel than petroleum. Peak demand can also occur from economic, or other forms of collapse, which we hope does not occur.

The beginning of oil, the end of oil. Mayhaps both.

More 9Nov10: Whether crude oil survives or is decomposed to wet and / or dry natural gas probably depends more upon the catalytic environment in the reservoir than the temperature. The presence of mineral catalysts changes the decomposition picture significantly. We may discover that much of the sub-seafloor methane clathrate resource is a result of this type of natural catalysis of crude oil to natural gas, which migrates upward to a cooler, moister environment and is captured in clathrate. Of course, abiotic gas might well do the same thing in some formations.

Oil From Ancient Seas: Where Ahoy?

Oil was formed in warm, ancient seas, from microscopic organisms which thrived in a high CO2 environment. The first photosynthetic micro-organisms evolved around 3.5 billion years ago, which provides a great deal of time for hydrocarbon formation through the eons. Modern oil companies are scooping up the most recently formed crude oil, from deposits formed just a few dozens or hundreds of millions of years ago -- from the ancient sea-beds and former sea-beds which were easy to locate. But where will we find the multi-billion year ancient seabeds -- the really big oil fields? It will require a great deal of patience, detective work, and advanced technological tools -- some of which have not been invented yet.

If you want to go prospecting in history for likely locations of super-giant oil deposits, look for the ancient sea-beds. The Wikipedia reconstruction of Earth's tectonic history should give you a rough idea of where the ancient seas may have been. The YouTube video below provides another look at the dynamic ballet of continents and plates. Pay careful attention, insert a bit of creative extrapolation and interpolation, and draw your own conclusions.

If you look down below at the Wikipedia clock representation of Earth's time scale -- far back into the pink -- you will see where photosynthesis begins, around 3.5 billion years ago. Then travel clockwise all the way through the pink and yellow to get to the blue and green, where the seabed locations of modern oil formation opened up to provide ideal environments for oil formation. What happened to all of the oil from the roughly 3 billion years between the start of photosynthesis and the generation of modern oil, originating from all of those wildly reproducing photosynthetic microbes?

If you watch the undulations of the tectonic plates, and the constantly opening and closing of sea basins over the 600 million years pictured in the YouTube video, you can see that the perfect windows for oil formation were constantly opening and closing. No sooner would a perfect warm sea open up for oil production, than the tectonic plates would shift and cover it up.

All the while massive vulcanisation was taking place within and around the sedimentary basins where rich oil deposits from past ancient seas were sitting in the boiling heat deep underground. What happened to all of those billions of years of deposits?

Some must have escaped as gas or volatile hydrocarbon, migrating to upper layers of the crust, or into the atmosphere. Some of the oil would have likewise found its way to upper layers of crust, trapped by impermeable layers -- or escaping as seeps to be metabolised by oil-munching microbes.

But some of it -- perhaps a huge part of it -- is still trapped beneath volcanic rock, beneath moving tectonic plates, beneath billions of years of sediment. Waiting for clever boys and girls to track it down.

More: Recent study of a massive rotational shift of the super-continent Gondwana approx. 525 mya

Growing awareness of rich variety of life beneath the seafloor

Deep open ocean most unexplored part of planet

It should be clear that since 70% of Earth is covered by ocean, most of the planet's treasure trove of petroleum and other fossil fuels is likely to lie beneath the seas. Both polar regions are relatively unexplored in terms of mineral wealth, but the same is true for the open oceans. Although it does not take a genius to suppose that large deposits of oil may lie in the Gulf of Mexico or under the ancient Tethys Sea, it may take a great deal of clever detective work to find earlier versions of these nutrient-fed warm water shallow seas -- and where the sediments may have migrated over the past hundreds of millions of years.

Ancient Geologic Upheaval Still Hides Most of Earth's Oil

NYTScientists have known for quite a while that most of Earth's oil came from vast numbers of oceanic microscopic organisms -- rather than from dead dinosaurs. From diatoms to micro-algae to cyanobacteria and more, these microscopic life forms thrived on warmer seas and higher levels of atmospheric CO2 than are presently available to sea life. Many of these sea creatures are capable of converting gaseous or dissolved CO2 directly into oils and hydrocarbons of various types, and would cheerfully welcome much higher levels of CO2 in the atmosphere and in the oceans, if only they could get it.

Geologists scour the planet for the sedimentary basins of ancient seas, in order to find the vast deposits of oil, gas, and other hydrocarbons still waiting to be discovered. Humans may have used perhaps one tenth of exploitable oil deposits, but Al Fin engineers reckon we have used only about one one hundredth. Not that oil is an ideal energy source. Far from it. But we should know that we are quite far from running out -- even while we are discovering how to grow these tiny organisms for ourselves, to produce a wide range of materials, feeds, and fuels at the time and place of our own choosing.

Some of the ancestral waters that made the planet’s oil still exist, like the Gulf of Mexico, while others have long vanished, like the ocean that produced the massive oil fields of the Middle East. The bodies come and go because the earth’s crust, through seemingly rigid, actually moves a great deal over geologic time, tearing apart continents and ocean basins and rearranging them like pieces of a giant jigsaw puzzle.

The secret of the oil story turned out to be understanding how the bygone oceans, ancient seas and smaller bodies of water produced complex environmental conditions that raised the prevalence of microscopic life and ensured its deep burial, producing what eventually became the earth’s main oil reservoirs.

The clues accumulated over more than a century and included discoveries from geology, chemistry and paleontology. An early indication was that petroleum discoveries were always associated with ancient beds of sedimentary rock — the kind that forms when debris rains down through water for ages and slowly grows into thick seabed layers.

...The process typically starts in warm seas ideal for the incubation of microscopic life. The sheer mass is hard to imagine. But scientists note that every drop of seawater contains more than a million tiny organisms.

Oil production begins when surface waters become so rich in microscopic life that the rain of debris outpaces decay on the seabed. The result is thickening accumulations of biologic sludge.

...“The organics got buried quickly because of the heavy sediment flow,” Dr. Tinker said. “So they didn’t get biodegraded as quickly. You preserved the organic richness.”

He said the flow was so heavy that the growing accumulations keep pressing the lower sediment layers deeper into the earth, forcing them into hot zones where the organic material got transformed into oil. The process involves a long series of chemical reactions that slowly turn life molecules into inanimate crude.

“The gulf has miles and miles of sediments,” he said. “So that gets the source rocks down into the kitchen where they cook.”

The standard temperature for oil formation is between 120 and 210 degrees Fahrenheit.

...Many countries and oil companies are now racing to exploit the geological happenstance of deep coastal waters. Hot spots include offshore areas of Angola, Azerbaijan, Congo, Cuba, Egypt, Libya and Tanzania, while countries like Canada and Norway, which have long pursued offshore drilling, are pushing ahead with new plans. Cambridge Energy Research Associates, a consulting firm, estimates that global deepwater extraction could roughly double by 2015, the output rivaling what Saudi Arabia produces on land. _NYT

The new offshore oil fields coming on line will rival Saudi Arabian production -- even if the Saudis decide to ramp up their production even higher than at present.

But many more giant fields await discovery until geologists develop better tools to find ancient ocean basins lying beneath subsequent overlaying deposits of seismic and volcanic upheaval. Earth's warm water sea floors have been turned around a great deal over the past billions of years. It is likely that we have not yet found the richest fossil fuel fields.

For most of the planet, geologists simply do not have a clue what lies beneath. They will need far better tools than the primitive seismic, electromagnetic, and other tools which currently limit their vision. But those tools are coming. And those vast unknown deposits will be found, if they are ever needed.

Previously published at Al Fin Energy