FTIR absorption indices for thermal maturity in comparison with vitrinite reflectance R0 in type-II kerogens from Devonian black shales

摘要: Abstract FTIR absorbance signals in kerogens and macerals were evaluated as indices for thermal maturity. Two sets of naturally matured type-II from the New Albany Shale (Illinois Basin) Exshaw Formation (Western Canada Sedimentary hydrous pyrolysis artificial maturation characterized by FTIR. Good correlation was observed between aromatic/aliphatic absorption ratio vitrinite reflectance R 0 . parameters are especially valuable determining degree maturity marine source rocks lacking vitrinite. With increasing maturity, spectra express four trends: (i) an increase aromatic bands, (ii) a decrease aliphatic (iii) loss oxygenated groups (carbonyl carboxyl), (iv) initial CH 2 /CH 3 that is not apparent at higher samples, but throughout artificially samples. The difference samples natural indicates short-term high temperatures fully equivalent to slow geologic lower temperatures. , (carboxyl + carbonyl)/aromatic carbon generally decreases, except experiments intermittent slight medium FTIR-derived aromaticities correlate well with although some uncertainty due dependence on maceral composition kerogen whereas solely dependent