aspects of organic geochemistry of nigerian coal university of ibadan

Abundant lycopanes have been reported in hypersaline euxinic settings (Grice et al.,
1998) and in mesosaline carbonates, such as the Jurassic Malm stage carbonates
(Schwark et al., 1998). Lycopane has been proposed to be a bacterial marker derived
from reduction of lycopene (Killops and Killops, 2005).
Squalene (structure V) serves as precursor to polycyclic terpenoids, steroids and
carotenoids. Squalene is a major lipid produced by methanogenic, thermophillic and
thermoacidophilic archaea. Abundant squalane, a saturated C30 isoprenoidal alkane,
may represent a direct archaebacterial input (Matsumoto and Watanuki, 1990) or
derive from diagenetic reduction of squalene, which occur in a variety of organisms.
Squalane has been used as a biomarker for archaea and hypersaline depositional
environments (Ten Haven and Rulkotter, 1988).
2.1.3 n-Alkanol, Alkanoic acids and Fatty acids
Aliphatic wax lipids (n-alkanols, n-alkanoic acids, fatty acids) in the range of
C22-C32 were identified as the major extractable components of angiosperm leaves,
barks and roots (Huang et al., 1995; Lockheart et al., 2000; Kogel-Knaber 2002;
Yuang and Huang, 2003). Similar distributions have been reported in sediments and
macrofossils (Logan and Eglinton, 1994; Huang et al., 1995, 1996; Lockheart et al.,
2000). The functionalized lipids are partly degraded during diagenesis (Bechtel et al.,
2001). The wax esters, their hydrolysis products, and the free alkanol and fatty acids
are preferentially degraded to aldehyde, ketones and alkanes by microorganisms
(Puttmann and Bracke, 1995). These degradation pathways favor short chain (