Kerogen formation

Collins, M. J., Bishop, A. N., and Farrimond, P (1995). Sorption by mineral surfaces rebirth of the classical condensation pathway for kerogen formation Geochim. Cosmochim. Acta 59,2387-2391. 

Derenne S., Largeau C., Casadevall E., Berkaloff C., and Rousseau B. (1991) Chemical evidence of kerogen formation in source rocks and oil shales via selective preservation of thin resistant outer walls of microalgae origin of ultralaminae. Geochim. Cosmochim. Acta 55, 1041-1050. 

The potential pathways to kerogen formation are combined in the scheme shown in Fig. 4.11, in which kerogen is seen to be the combination of resistant biomacromolecules, geomacromolecules, sulphur-rich macromolecules and incorporated LMW biomolecules. The extent to which humic material contributes to kerogen is uncertain. Partial alteration of biomacro-... 

Fig. 4.11 Simplified model of kerogen formation incorporating classical and selective preservation models. Kerogen is represented by the combined four boxes at the bottom, whereas the preserved lipid components box represents a constituent of bitumen.

Derenne S., Largeau C., Behar F. (1994) Low polarity pyrolysis products of Permian to Recent Botryococcus-rich sediments first evidence for the contribution of an isoprenoid algaenan to kerogen formation. Geochim. Cosmochim. Acta 58, 3703-11. 

Fig. 4.10 The selective preservation pathway model of kerogen formation (after de Leeuw and Largeau 1993 and Tegelaar et al. 1989).

Fulvic acids and subsequently humic acids decrease in their concentrations over time as a result of progressive combination reactions with increasing diagenesis. This process of kerogen formation concurrently involves the elimination of small molecules like water, carbon dioxide, ammonia or hydrogen sulfide (Hue and Dmand 1977). As a consequence, the degree of condensation of the macromolecular kerogen increases. In terms of elemental composition it becomes... 

SELECTED CASE STUDIES OE TYPE II-S KEROGEN FORMATION ... 

Tegelaar E. W., de Leeuw J. W., Derene S. and Largeau C. (1989b) A reappraisal of kerogen formation. Geochim. Cosmochim. Acta 53, 3103-3106. 

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