EARTH SCIENCE
GEOCHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Forms when organic shale is buried under several layers of sediment and is cooling .
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Forms under conditions of little or no oxygen in the water, which preserved the organic material from decay.
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Forms when organic matter in sediment is buried under several layers of sediment, undergo coalification (condensation) process and is heated.
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Forms in shale materials have a mixed clay mineralogy of smectite and kaolinite with depth.
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Detailed explanation-1: -Like petroleum, kerogen is thought to have originated from compacted organic material, such as algae and various forms of plant life, that accumulated at the bottom of ancient lakes and seas and was buried at great depths over long periods of geologic time.
Detailed explanation-2: -Kerogen is formed during sedimentary diagenesis from the degradation of living matter. The original organic matter can comprise lacustrine and marine algae and plankton and terrestrial higher-order plants.
Detailed explanation-3: -Stages in Kerogen Maturation The pathways of maturation and evolution of kerogen include (1) diagenesis, (2) catagenesis, and (3) metagenesis.
Detailed explanation-4: -In a steadily subsiding sedimentary basin, the transformation (maturation) of organic matter to kerogen and its subsequent maturation to oil and gas happens under three different stages of burial viz. diagensis, catagenesis and metagenesis (Tissot, 1977).