We are frequently told we are running out of oil. Often this is accompanied by statements that we’ve drilled just about everywhere there is. Never mind that we have locked up large areas of land to NOT drill (many of which are known to be oil rich, such as the California offshore and parts of Alaska).
But what if there were another 70% of the Earth, largely not explored, that might harbor hydrocarbons?
DEEPWATER FRONTIERS Abyssal hydrocarbons off West Africa indicate widespread potential
Ten tons per sq meter hydrocarbon yield possible from 5,000-meter thick sedimentation zones
A number of abyssal basins on both sides of the Mid-Atlantic Ridge and bounded by east-west fractures hold substantial thickness of sedimentation and hydrocarbon-rich black shales. The named basins shown here are in water depths of 4,000-5,000 meters.
We’re talking a few miles deep water here. And that Mid-Atlantic Ridge Ridge is not exactly “near land”…
The article goes on to posit that during the time Africa and The Americas split, the water flow between them was somewhat stagnant, so sediments and organic deposits could accumulate and do the usual oil formation. OK, I can see that. OTOH, I’ve got to admit to wondering if maybe there isn’t just a whole lot more oil a whole lot deeper down that folks want to admit.
At any rate, we’ve now got The Atlantic Oceans as “Oil Land” to explore…
Three extensive hydrocarbon deposits have been found in 4,000-meter deep abyssal plains off the northwestern coast of Africa. The deposits, from Cretaceous age sediments, were encountered during drilling conducted by the Deep Sea Drilling Project’s rig Glomar Challenger and tracked later through other areas by seismic evaluation.
The black shale deposits were cored from an area south of the Cape Verde Islands in the Gambia Basin. Later investigation by seismic vessels determined that the sequences found during coring conducted in the Gambia Basin extended throughout the basin and were found in similar depths in other basins located along the equatorial Atlantic.
The seismic evaluations were announced by E. J. W. Jones of University College London, who participated in geological analysis of the results of the coring and seismic expeditions.
In addition to the hydrocarbon-rich rocks, drillers also found accumulations in water depths as shallow as 800 meters that were rich in phosphorus and ferromanganese oxides. Cobalt levels in some cases were as high as 1%. The phosphate deposits were found in the cappings on seamounts and fault-bounded ridges. One accumulation was located by bottom-towed scintillometer because of the radioactivity issued in the region.
So about that “running out” of minerals and phosphates? We can’t “run out”, as the stuff doesn’t go away. It might end up on the bottom of the ocean, conveniently concentrated, but we NEVER run out of elements…
I also note that NATURAL higher levels of radioactivity were used to find some of it.
Analysis of the drilling cores showed a 34% planktonic kerogen level with high hydrocarbon and hydrogen ratios. Jones said that compared with other deepwater deposits in the world’s oceans, the Gambia Basin had some the highest hydrocarbon ratios known, exceeding 10 tons per sq meter, if it is assumed the source rock is buried to a depth at which maturation of kerogen would occur.
Seismic profiles show the reflector (No. 2) atop the black shale zone shows up over a wide area of the equatorial Atlantic. Jones said that thickness in the Sierra Leone, Guinea, and Demerara basins were equal to or greater than the Gambia Basin zones.
Add in that we’ve got Asphalt Volcanoes and hydrocarbon seeps from deep water in the Gulf Of Mexico, and there’s a whole lot more hydrocarbons to find out there.
Asphalt being colonized on the bottom of the ocean:
Scientists exploring the deep sea in the Gulf of Mexico have discovered seeps that resemble a paved road. Seeps are places where oil and other hydrocarbons bubble up from under the seabed. But these seeps, discovered by researchers with Texas A&M University at Corpus Christi, are covered in asphalt.
The seeps were found along salt domes that lie about two miles down in the southern Gulf of Mexico. Deep sea cameras revealed about 20 salt domes that had collapsed or broken apart. Along the edges were large patches of asphalt, or hardened tar. Scientists photographed them and took samples; they say the material is similar to asphalt pavement, and was probably squeezed out of the seabed like lava.
Oil seeps have been found in most of the world’s oceans, but none with hardened material like this, according to a paper in this week’s issue of the journal Science. The scientists also found communities of tube worms, mussels, clams and shrimp living on or near the asphalt. These animals are similar to ones living near deep sea vents, and live off of the chemicals emitted from the vents and seeps.
The asphalt deposits are the result of a violent expulsion of hydrocarbons, and indicate untapped deep-water oil reserves. Scientists had thought the region was relatively stable, but this discovery of underwater “volcanoes” shows “how much more there is to learn about the deep sea,” says Texas A&M researcher Ian MacDonald. “The abundance of animal life is more proof of the adaptability of marine organisms.”
Asphalt volcanism has been introduced as a novel type of hydrocarbon seepage by MacDonald et al. (2004). The authors found asphalt deposits with lava-like appearance at the seafloor in more than 3000 m of water depth in the southern Gulf of Mexico. The term asphalt was used to signify the solid state of the petroleum deposit that was composed of a degraded, unresolved complex mixture of hydrocarbons with a peak at n-C30 and a few resolved C29–C32 hopanes. The asphalts occurred in an area of approximately one square kilometer on one of the Campeche Knolls that was subsequently named Chapopote, the Aztec word for tar.
We also know that over time the continents have spread apart, broken up, and been mushed back together several times. IMHO, there ought to be many more such places, of many more ages, located all over the place. Not everywhere, as some places will be too young, or too old and degraded. Just like we don’t find oil everywhere on land.
But given that we’re frequently told how little we know of the deep sea abyssal plains, there’s a whole lot of empty to explore. And we’re already finding oil in them.