Kerogen-like material

The kerogen-like material from the Murchison meteorite is shown in Figure 6.8 and consists of a rich macromolecular carbonaceous material made from aromatic and aliphatic compounds observed in fluorescence following excitation at 280 nm. 

Coercevate The enclosed lipid structure that forms from an acid extraction of kerogen-like material in the Murchison meteorite. 

Kerridge J. F., Chang S., and Shipp R. (1987) Isotopic characterization of kerogen-like material in the Murchison carbonaceous chondrite. Geochim. Cosmochim. Acta 51, 2527-2540. 

Morgan W. A., Feigelson E. D., Wang H., and Frenklach M. (1991) A new mechanism for the formation of meteoritic kerogen-like material. Science 252, 109-112. 

The Murchison meteorite shown in Figure 6.7, like all meteorites, is named after the place from which it was recovered and in this case it is the town of Murchison, Victoria in Australia about 100 km north of Melbourne. The fall occurred in 1969 and was followed by an analysis of the chemical composition in some considerable detail. The Murchison meteorite is a carbonaceous chondrite containing about 2 per cent carbon, some as inorganic carbonates, and some as soluble compounds such as amino acids but the bulk as a macromolecular heterogeneous material referred to as kerogen. 

Combined stable isotope analysis ( C, D, N, has been used successfully in petroleum exploration (Stahl 1977 Schoell 1984 Sofer 1984). The isotopic composition of crude oil is mainly determined by the isotopic composition of its source material, more specifically, the type of kerogen and the sedimentary environment in which it has been formed and by its degree of thermal alteration (Tang et al. 2005). Other secondary effects like biodegradation, water washing, and migration distances appear to have only minor effects on its isotopic composition. 

We start out by considering the effect of such adsorption sites on the isotherms of apolar and weakly monopolar compounds. For these types of sorbates, hydrophobic organic surfaces and/or nanopores of carbonaceous materials are the most likely sites of adsorption. Such hydrophobic surfaces may be present due to the inclusion of particles like coal dust, soots, or highly metamorphosed organic matter (e.g., kerogen). Because of the highly planar aromatic surfaces of these particular materials, it is reasonable to assume that planar hydrophobic sorbates that can maximize the molecular contact with these surfaces should exhibit higher affinities, as compared to other nonplanar compounds of similar hydrophobicity. 

---