kerogens

Oil Shale contains bituminous solids called kerogens that are released as petroleum-like liquids when the rock is heated to sufficient temperatures (somewhere around 600 to 700 F).

Earth & Sky Podcast 2009

Permian kerogens from Autun, Fr., and Carboniferous and Permian torbanite from Scotland, Australia, and South Africa appear to consist almost exclusively of Botryococcus colonies, as does Recent post-Pleistocene coorongite from

The Democratic Party's email attacking Jerome Corsi (author of the #1 selling anti-Obama book). Ann Althouse 2008

Some oil shale kerogens are composed almost entirely of algal remains, whereas others are a mixture of amorphous organic matter with a variable content of identifiable organic remnants.

The Democratic Party's email attacking Jerome Corsi (author of the #1 selling anti-Obama book). Ann Althouse 2008

Much more of the ancient organic carbon is sequestered in kerogens, which are transformed remains of buried biomass found mostly in calcareous and oil shales.

Global material cycles 2007