Kerogen cross-links

The different properties of sulfur-rich kerogen and asphaltenes, on the one hand, and sulfur-rich resins on the other hand (flash pyrolysis behaviour) may be explained only by differences in degree of (sulfur) cross-linking and thus by differences in molecular size and in degree of condensation. 

Larsen J.W., Parikh H., Michels R. (2002) Changes in the cross-link density of Paris Basin Toarcian kerogen during maturation. Org. Geochem. 33, 1143—52. 

A simple model of two parallel independent first-order reactions was found to closely describe the decomposition of an oil shale kerogen from the Rundle deposit in Australia. The model was based on the fractions of mobile and rigid components in the kerogen, inferred from the NMR data. A major aspect of the model was that the macromolecular material in the oil shale kerogen had a bimodal distribution of cross-link density. During heating, a... 

Oil shale is a kerogen-containing porous rock of low permeability that occurs in Brazil, the USA, and the USSR. Kerogen is a cross-linked high-molar-mass wax. The sources in Utah, Wyoming, and Colorado contain about 25-250 kg kerogen per ton of oil shale, and the U.S. sources east of the Mississippi contain less kerogen. 

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