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Home / Opinion - Why has the finding of oil been illusive of the geological minds?

Opinion - Why has the finding of oil been illusive of the geological minds?

2021-09-03  Staff Reporter

Opinion - Why has the finding of oil been illusive of the geological minds?
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The teaching of geology is that hydrocarbons are the result of deep burial of organic matter that got subjected to high temperature and pressure before they turn into hydrocarbons, including petroleum, during the carboniferous period more than 350 million years ago.

The knowledge of geology further prescribes that for hydrocarbons’ reserve to be found somewhere underground, three conditions must be met. These conditions are the right temperature and pressure or burial depth, the source rocks and the cap rocks. The temperature and pressure or burial depth determine the type of hydrocarbons that one is likely to locate. 

That is whether you find coal, oil or gas. The source rocks are the starting point of the generation of hydrocarbons and they are the types of rocks in which the hydrocarbons get generated. The cap rocks are the types of rocks in which the hydrocarbons get collected because after the hydrocarbons migrated from the source rocks, they get trapped in the cap rocks due to the impermeability of such rocks.

There is also one thing that needs to be considered when exploring hydrocarbons, including oil and such a thing is that there is no geographical relation to the generation, trapping and preservation of oil. Oilfields are found in Africa, Middle East, South America, North America and Europe. Both the Southern Hemisphere and the Northern Hemisphere have oilfields already discovered. The factor that oil can be found anywhere in the world should be the possible reason that gives hope to those who had been steadfast in investing millions of dollars in the search for oil in Namibia. 

However, there is one thinking that always crops up in the arguments of those who believe that we may also have oilfields in Namibia waiting to be discovered. This thinking is that there are oilfields in South America, especially in Brazil, and since the geographical positions of the oilfields in Brazil were once fitted to the corresponding landmasses in Southern Africa when the globe was once a single landmass called Gondwana, then the corresponding geographical regions in Southern Africa, including those in Namibia, may also have oilfields waiting to be discovered. 

I believe that this is twisted logic. One has to take into account that Gondwana landmass started breaking up billions of years ago and the oil generation coincides with the mass burial of organic materials during the Carboniferous period about 200 to 300 million years ago. 

The question is what has happened to the two separate regions ever since? Obviously, the two regions got subjected to climatic and geological processes that might not have been similar and the economic importance of the two geologic regions may not be similar today. The geologic processes to which the two regions might have been subjected include magmatism, volcanism, metamorphism, sedimentation and tectonism. 

Even if it can be argued or proved that the Southern American and the Southern African geological regions which formed the neighbouring Gondwana landmasses contained oil or geological conditions suitable for generation and preservation of oil, then it should be born in mind what happened as far as magmatism, volcanism, metamorphism, sedimentation and tectonism are concerned might have led to two different evolutionary paths of the two regions and may point for the possibility of the Southern African region being barren or sparsely-endowed while the Southern American one rich in oil. 

Given the aforesaid background, the oil potential for 

Namibia has to be determined by answering the following questions. Do we have the right lithology of source rocks for the generation of oil? If not, do we have the right lithology for cap rocks and have ample evidence that oil migrated from the source rocks in the geologic region outside of our geographical boundary and get trapped in the cap rocks in a geologic region within our geographical boundaries? 

Alternatively, do we have both the source rocks and the cap rocks in the geologic regions within our geographical boundaries? Even if the above-asked questions are answered, there is still an acid test to be passed. 

This is whether the overall geological history of the region being explored for oil is compatible with the generation, migration and eventual preservation of oil.  Unless these million-dollars issues are settled, we will continue to hunt for the illusive black gold of Namibia for many years ahead unsuccessfully.

 

*Dr David Kamati is a former student activist, ex-science teacher, and has worked as a human rights activist between 2004 and 2011. He holds six university qualifications in Geology, including a Doctorate of Science (DSC) from the prestigious University of Natal in RSA. His post-graduate research topics covered the fields of economic geology and mineral exploration. He is currently unemployed and writes in his capacity as a free citizen. Dr Kamati can be reached at dkuuyyni@gmail.com or 0812327351.

 


2021-09-03  Staff Reporter

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