Influence of floral assemblage, facies and diagenesis on petrography and organic geochemistry of the Eocene Bourgas coal and the Miocene Maritza-East lignite (Bulgaria)

Enhanced thermal maturation of organic matter during diagenesis is reflected in higher contents of n-alkanes and the presence of alkyl naphthalenes in the Bourgas coals. Alkyl naphthalenes are thought to have been formed from pentacyclic triterpenoids rather than from resinous compounds.