Creating a realistic world map - Fuel

Question

This Query is part of the Worldbuilding Resources Article.

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Following the question Creating a realistic world map - Mineralogy , I realized that it was a very large topic to cover all the possible resources. Now, I would like to focus on the natural resources that can be used as source of fuel.

To be more specific: Coal, natural gas, petroleum, uranium (Or any resources that goes into a long geological process and that can be used to produce energy.)

Is there a technique to help me place these resources in my world? Should I expect some of them to be located close to each other?

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Note:

This is part of a series of questions that tries to break down the process of creating a world from initial creation of the landmass through to erosion, weather patterns, biomes and every other related topics. Please restrict answers to this specific topic rather than branching on into other areas as other subjects will be covered by other questions.

These questions all assume an earth-like spherical world in orbit in the habitable band.

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See the other questions in this series here : Creating a realistic world Series

Answer 1

On our mother planet, earth, these mineral (and fuel) resources are formed and located as such:

1- Coal And Oil

The coal and oil on our planet were formed tens of millions of years ago by the decay of plant or animal matter deep underground where the pressure and temperature were high and oxygen was absent. In your world, too, these resources should be formed likewise.

WHERE they are located, is a matter of subjectivity. If you want to get oil reserves on the poles, you will have to allow the now-polar landmasses to once be on the tropical belt (plate tectonics, remember?) with abundant flora. Due to reasons lame and unknown, conditions later changed and the plants were gradually buried under dust storms and vast areas destroyed due to orogenies and fault lines etc. The landmass gradually drifted towards the pole and so in modern times ...

2- Rock Salt, Gypsum And Other Evaporites

Evaporites are basically metal salts that are deposited in a region where seawater is trapped in large quantities and then evaporates, leaving big, huge, giant, colossal quantities of these salts.

Evaporite reserves are formed in hot, arid regions. Consider a very large, deep valley that used to get large quantities of seawater with hurricanes, every few months and was flooded 2-3 feet in seawater. Then the seawater evaporated, leaving behind alkali sulphates and chlorides. Over a course of a few million years, this process was repeated. All the flora of the valley died due to excess salt in it's soil. It turned into a desert area. Then due to tectonic activity the whole region was lifted 100 meters or so as new mountain ranges were built close by. Now there are large reserves of evaporite salts in that region.

Uranium And Other Radioactive Elements

Here we are talking about the leftover quantities of a huge star that exploded billions of years ago. All the heavy elements like uranium, plutonium etc are made in huge stars just before they go supernova. There is no cycle of replenishing their quantities on planets.

These elements can be placed anywhere as you like in your world, but remember, if your planet was once in molten state, the heavier elements would tend to sink down towards the core ...