H. Budzinski, P. Garrigues, J. Connan
May 1, 1995
Citations
12
Influential Citations
177
Citations
Quality indicators
Journal
Geochimica et Cosmochimica Acta
Abstract
Abstract Methylphenanthrene (MP), dimethylphenanthrene (DMP), and trimethylphenanthrene (TMP) distributions have been determined in crude oils and rock extracts from different origins at various stages of thermal maturity. A methodological approach combining Correspondence Factor Analysis and Nonlinear Mapping (NLM) was used for extracting origin/maturity information from these data. It allowed to benefit from the advantages of both methods. The use of such a multivariate data analysis appeared much more efficient than the use of molecular ratios that can be too restrictive and mask specific distribution patterns. This approach performed on the set of natural samples clearly demonstrated the discrimination between the samples through the presence of specific methyl-, dimethyl-, and trimethylphenanthrene isomers as origin/maturity markers. Based on MP, DMP, and TMP distributions, it is possible to distinguish the variations in organic matter type from the effects of thermal maturation. Some substituted phenanthrenes in each isomer series appear as characteristic of the two studied systems: The Aquitaine basin as representative of a marine carbonate environment and the Mahakam delta as representative of a terrestrial environment (higher plants). These compounds could be tentatively related to natural precursors such as triterpenoids or hopanoids.