Evidence for sulphide links in a crude oil asphaltene and kerogens from reductive cleavage by lithium in ethylamine

Evidence for gammacerane as an indicator of water column stratification

“…These sediments are also extremely rich in organic sulphur (Rullkotter et al, 1990)) indicating that extensive sulphurisation of organic matter has occurred. The S-sequestration pathway is also supported by reports that gammacerane is a major product of desulphurisation of S-rich macromolecular aggregates (e.g., asphaltene and kerogen fractions) with, in cases where deuterium labelling was employed, mainly one deuterium atom incorporated (Richnow et al, 1992(Richnow et al, , 1993Hofmann et al, 1992;Adam et al, 1993).…”

“…The kerogen of the related Jurf ed Darawish Oil Shale contains significant amounts of Sbound gammacerane (Hofmann et al, 1992). It is, therefore assumed that the kerogen is the major source for the gammacerane formed upon hydrous pyrolysis.…”

The comparison of biomarkers released by hydropyrolysis and Soxhlet extraction from source rocks of different maturities

“…The Ts/(Ts+Tm) ratio of the hydropyrolysates is significantly lower than that of the Soxhlet extracts for the WC series. Previous studies [12,[49][50][51] suggested that the carbon skeletons of bacteriohopanepolyols precursors are cross linked to kerogen geo-macromolecular networks by multiple heteroatomic linkages. Thus, Tm was restrained to be transformed into Ts in the hydropyrolysates because the covalently bound biomarkers were protected by geo-macromolecular networks.…”

Differences in the thermal evolution of hopanes and steranes in free and bound fractions

“…A great number of studies have reported that hopanes and steranes also can be released from kerogen and/or solid bitumen by thermal pyrolysis, chemical degradation and catalytic hydropyrolysis (Seifert, 1978;Tissot and Welte, 1978;Mackenzie et al, 1982aMackenzie et al, , 1982bMycke and Michaelis, 1986;Eglinton and Douglas, 1987;Mycke et al, 1987;de Leeuw et al, 1989;Abbott et al, 1990;Hoffman et al, 1992;Richnow et al, 1992;Adam et al, 1993;Love et al, 1995;Muhammad and Abbott, 2012). Various conditions (temperature and time) have been used for thermal pyrolysis.…”