Another problem concerning the formation of oil in subduction zones is the transport and retention of oil in the rock or layer of debris.
Click on image to enlarge The problem initially was that the remains of plants are expected to settle to the bottom of the ocean and there no sediment is going to ask it. The debris layer is above the ocean floor rock. And normally, the oil will be produced in this layer of debris.
There is no reason that oil is found in the rock, as it is formed in a layer that is above the rock. So already, it is unclear how it can be in it thereafter.
And we do not even mention the fact that it is often found at 4 or 5 km below the surface, then it is supposed to be formed at a depth between 2 and 3 km and it is supposed to then go back immediately.
But in addition, there is the problem of blocking oil when it goes back to sea level of the plate. To reassemble, the oil must pass through either layer of debris (the most logical assumption) or through the rock that lies beneath the debris.
Consider first the crossing of the layer of debris. If the layer of debris passes oil, then it means it is permeable to it. So we do not see why, once back in the sea, via the layer of debris, oil would remain in the layer of debris. It should instead go back into the sea and be lost.
In this drawing, I strongly thickened layer of debris to avoid having to zoom too. Well, it sure is not a Rembrandt, but the elements are there. As can be seen, the oil passes through the layer of debris and leaves in the sea This problem remains the same if one considers the rock . If oil can get in the rock of the sea plate, then it means it is permeable to oil. So, it should eventually be lost in the sea
Oil passes through the rock layer. But since there is no impervious area, it is apparent in the sea And a priori, it is difficult to say that the top layer of impermeable rock is marine oil. First you may think that the constitution of the rock is identical to hundreds of meters thick, because it is a rock formed by magma of a ridge sea. So there is no reason that the top of the slab is more impermeable layers that a little deeper. But more importantly, because the debris were seen above the rock, oil from cross it before rising to the surface. So if it went through the top layer of rock, it means that it is permeable to oil. Especially as all this is that supposed to happen over an area several kilometers wide, it is not sure why the composition of the rock sea fundamentally change a few kilometers.
And even assuming that there one or two layers of impervious rock , given that oil is supposed to go back permanently along the sea plate to avoid being pushed forward in the mantle, this means that at one time or another It would be faced with a permeable rock. And therefore, he could get through this rock and get lost in the sea
Or, if oil is found trapped in a hollow waterproof, it could move more, and would be subject to movement Sea plate. And he would slowly toward the subduction zone. And then there are two possibilities. Let , with tipping plate at 45 °, it would no longer be retained in the hollow. He then began to rise again. And he again encounters an impermeable hollow, the same operation will be repeated. Otherwise, it will be lost in the sea eventually, he will end up being bound in a cycle where it will not encounter impermeable hollow. So it will end up being necessarily lost. Let remains trapped in the rock, and eventually resulted in the mantle with him.
The oil gets stuck in the rocks because of low sea waterproof. 
Yes, but the trough moves with the plate. And then, quickly, within a few tens of thousands of years, the hollow is no longer in the right direction and lets the oil is lost into the sea again And even if it was not the case The oil would then be driven deep into the hollow. could also think about the possibility that oil remonstrated in the rock and the layer of plant debris is impervious to oil. But in this case, we would not find oil at 3 or 5 km beneath the ocean floor, but only a few tens of meters (and than one hundred meters).
And also, a priori, I do not think we say that there is still a layer of debris on the ocean floor. We must think there is enough plants to do so and it was a phenomenon peculiar to the dinosaur age. So we must think the last bit of debris layer turned into oil long ago. So, as there would be more then a layer of debris, we could not defend the idea that oil would eventually be blocked by it.
the way, it means that the idea of horizontal infiltration of oil that I mentioned in the article precedent would be set aside by this problem. This idea could justify the presence of oil far into the sea plate. But if oil is lost in the sea, precisely because it can seep into the rock to get to the cross, it does have more possibility to have oil on the side of the plate sea. And therefore, we are left with the problem is the complete absence of oil (because wholly lost) or a field as a very thin strip.
One might think that the oil could be trapped under the plate land. But already, we must see that the tectonic plate sinking sea very rapidly under the land plate, at least 45 °. Oil is formed only 2 km maximum (depth and length) of the beginning of the depression of the sea plate. And the zone of oil formation oil itself as having only 1 km wide. Assuming that the oil spread over a greater width in back, it would leave only about 2 km wide, up to hold oil. So anyway, the field would be very thin, as previously noted.
ago two options regarding the retention of oil by terrestrial rock. Let the rock is immediately impermeable to oil (ie, just above the layer of debris), or it is only after .
If the rock is impermeable land immediately oil (ie oil does not sink into the rock. It is immediately blocked it), then, as the Marine plate makes an angle with the ground plate, it is not in a situation where there would be one or more hollow. So, normally, the oil should go up along the bend and out into the sea
The terrestrial rock is impervious to oil immediately. So it goes in the layer of debris and is lost in the sea Sometimes, on some representation of the subduction zone, there is a place which the bend is flat. Which would mean that eventually, the oil may remain stored in this area if the land was immediately impermeable rock. But then either the oil remains in the corner of the elbow, and in this case, there is always the problem of the width of the oil field. Or it extends to the sea, and in this case, it should reach the junction of the plate and out.
But in fact it should not be any horizontal area. Otherwise, it would mean that the plate Maritime fell below the earth plate. And suddenly, the plate sea would have no reason to do after an elbow. It would pass under the earth plate. So what needs to happen is that the plate is simply stopped shipping the ground plate and password below. And it does not logically an angle of 45 °, but almost 90 degrees. So there is no area for the storage of oil. Oil rises along the terrestrial rock, but it has no place to stop. And no question that it cannot earth plate. Because it falls on the fact that the blow, the sea does not sink plate at 90 °, but would slide under the Earth plate. You really have a frontal impact with the ground plate for there depression of the plate and not slipping.
Second possibility, oil rises in terrestrial rock (which is not impervious to the beginning).
Already, of course, requires that the oil rises in a hollow . Because otherwise, with a flat area, the oil could seep over the sides of the area is being lost (in the sea, air, or in the magma). And with upward sloping areas, he remonstrated, then slip along the impermeable zone before going out to sea or air. And must the upper trough is well above the zone of oil formation. Otherwise, the side of the mountain, oil could end up in the magma flow. And of course, this very special configuration of hollow exactly the right place may be quite rare. So there will be plenty of places where it can not be any oil in the mountains (and therefore no oil at all, since we saw as other places, it can not exist).
only viable solution. Oil rises in rock on Earth, which is permeable to the top, but not anymore after a few hundred meters or a few kilometers. The problem is that the width of the field is then only 1 or 2 km max. could have an area within a large hollow in the mountains. And so, oil would end up first at the periphery of large hollow, then remonstrated to the top of the mountain to the summit of the great hollow. But it seems hardly possible, because the top of the trough would have every chance to recover while in the magma flow, which would entail the loss of oil.
The trough is wider. Yes, but suddenly, the magma rises into it. In fact, assuming that the mountain has a slope of 45 °, it would mean that every mile is one kilometer in height would entail is long. So, like a mountain of average height is only 6 or 7 miles high, it would mean that the oil storage area would have only a maximum width of 4 or 5 kilometers. Indeed, it is conceivable that in the end zone 6 or 7 km depth, the magma is present and then burning the oil. So if there were large hollow, it would only 4 or 5 km.
So even if oil had the opportunity to stay in the ground plate, the field would have only a tiny width.
In addition, we may say that if oil can go, maybe that magma could also happen. So there is still a good chance that there is an infiltration of magma into the great hollow in question.
course, this kind of thing could not happen on the other side, the side sea or air, since there would be no room for the great hollow. The summit of the great hollow should be outdoors. And so, in fact, it would have only ascending slope.
If the depth was wider on the other side, of course, the summit would fall in vacuum. So we would really just upslope. And oil is apparent in water or air Free. And in addition, a priori, there was almost no oil found in the mountains. So it does not seem to defend this kind of theory.
So the only possibility that there is oil in an area of subdution is that it goes back into the rock of the earth plate (hence the rock is permeable to start, but is no more later), and there met a small or a large recessed area. Large hollow area that can not be found until near the ground. And even if these conditions are present, the fields have a width of 4 or 5 km max. And he would be in the mountains.
So anyway, at best it would field a very thin, especially low ability. We would not field giant. But mostly, there should be anything at all.
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