Carbon Trends (Dec 2023)
Biomass transformation towards diamondoids and beyond
Abstract
Adamantane (AD) is the first member in diamondoids family. It is an alkane of C10H16 formula, having a cage structure consisting of three fused cyclohexane rings. It was formed during biomass transformation towards crude oil, during final stages of catagenesis and on-set of metagenesis. It's appearance coincided with disappearance of biomarkers. Biomass origin of AD is indisputable although similar structures were not found in any type of biomass. Yet,precursors to AD arose from biomass.The occurrence and survival of AD in crude oil was attributed to its high thermal stability. In reservoirs, biodegradation of ADs was noted. With progress of burial, cracking of AD left behind in source rock, aided by temperature, lythostatic pressure and acidic mineral matter, occurred. Graphite, rather than diamond was an ultimate product of the final AD transformation. Much higher temperatures and pressures are required for the conversion of AD to diamond than that to graphite.
