
1) Oil-producing matter in shale 2) Source of shale oil
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https://www.crosswordclues.com/clue/kerogen

Kerogen (Greek κηρός `wax` and -gen, `that which produces`) 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 high molecular weight (upwards of 1,000 daltons or 1000 Da; 1Da= 1 atomic mass unit) of its component compounds....
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http://en.wikipedia.org/wiki/Kerogen

complex mixture of compounds with large molecules containing mainly hydrogen and carbon but also oxygen, nitrogen, and sulfur. It is the organic ... [4 related articles]
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http://www.britannica.com/eb/a-z/k/23

Aged and degraded carbon that was once assimilated by living organisms; for example, the molecules found in coal.
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http://www.daviddarling.info/encyclopedia/K/kerogen.html

A mixture of organic substances found in many fine-grained sedimentary rocks and a major constituent
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http://www.encyclo.co.uk/local/22392

Solid, waxy mixture of rock is heated to high temperatures, the kerogen is vaporized. The vapor is condensed and then sent to a refinery to produce gasoline, heating oil, and other products. See oil shale, ...
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http://www.encyclo.co.uk/visitor-contributions.php

A mixture of organic substances found in many fine-grained sedimentary rocks and a major constituent of oil shale.
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http://www.scientificpsychic.com/etc/geology-glossary.html

the bituminous matter in oil shale, from which shale oil is obtained by heating and distillation.
Found on
https://www.infoplease.com/dictionary/kerogen
No exact match found.