Source rock
In petroleum geology
Petroleum geology
Petroleum geology refers to the specific set of geological disciplines that are applied to the search for hydrocarbons .-Sedimentary basin analysis:...

, source rock refers to rocks from which hydrocarbons have been generated or are capable of being generated. They form one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been deposited in a variety of environments
Sedimentary depositional environment
In geology, sedimentary depositional environment describes the combination of physical, chemical and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be formed after lithification, if the sediment is preserved in the rock...

 including deep water marine, lacustrine
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 and deltaic
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...

. Oil shale
Oil shale
Oil shale, an organic-rich fine-grained sedimentary rock, contains significant amounts of kerogen from which liquid hydrocarbons called shale oil can be produced...

 can be regarded as an organic-rich but immature source rock from which little or no oil has been generated and expelled.
Source rocks are classified from the types of kerogen
Kerogen is a mixture of organic chemical compounds that make up a portion of the organic matter in sedimentary rocks. It is insoluble in normal organic solvents because of the huge molecular weight of its component compounds. The soluble portion is known as bitumen. When heated to the right...

 that they contain, which in turn governs the type of hydrocarbons that will be generated.
  • Type 1 source rocks are formed from algal remains deposited under anoxic
    Hypoxia (environmental)
    Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...

     conditions in deep lakes: they tend to generate waxy crude oils when submitted to thermal stress during deep burial
  • Type 2 source rocks are formed from marine planktonic and bacterial remains preserved under anoxic conditions in marine environments: they produce both oil and gas when thermally cracked during deep burial.
  • Type 3 source rocks are formed from terrestrial plant material that has been decomposed by bacteria
    Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

     and fungi under oxic or sub-oxic conditions: they tend to generate mostly gas with associated light oils when thermally cracked during deep burial.

It may be necessary to use methods other than constitutional ones.

"ZAPU deposes Mr. Nkomo as Leader", The Times, 9 July 1962, p. 9.

Our votes must go together with our guns. After all, any vote we shall have, shall have been the product of the gun. The gun which produces the vote should remain its security officer – its guarantor. The people's votes and the people's guns are always inseparable twins.

Martin Meredith, "Our Votes, Our Guns: Robert Mugabe and the Tragedy of Zimbabwe".

We are still exchanging blows with the British government. They are using gay gangsters. Each time I pass through London, the gangster regime of Blair

expresses its dismay'.

What we hate is not the color of their skins but the evil that emanates from them.

Speech in Harlem, New York (September 2000), quoted in Michael Radu, "State of Disaster", National Review, 27 May 2002

Our party must continue to strike fear in the heart of the white man, our real enemy!

"Whites are real enemy, warns Mugabe", Irish Times, 15 December 2000, p. 11.

The white man is not indigenous to Africa. Africa is for Africans. Zimbabwe is for Zimbabweans.


We have fought for our land, we have fought for our sovereignty, small as we are we have won our independence and we are prepared to shed our blood…. So, Blair keep your England, and let me keep my Zimbabwe.

Speech at the Earth Summit in Johannesburg (2 September 2002), quoted in John Battersby and Andrew Grice, "Anti-West anger at summit as Mugabe rounds on Blair", The Independent, 3 September 2002, p. 1.

Let Blair and the British government take note and listen. Zimbabwe is for Zimbabweans. Our people are overjoyed, the land is ours. We are now the rulers and owners of Zimbabwe.

Michael White, Andrew Meldrum, "Commonwealth leaders delay decision on defiant Mugabe", The Guardian, 6 December 2003, p. 2.