Ratios of certain biomarkers can be used to estimate the thermal maturity of crude oils and source-rock organic matter. Attempts have been made to calibrate maturation-dependent biomarker ratios to other measures of thermal maturity, such as vitrinite reflectance (R 0 Figure B7). R 0 is determined by microscopy and can be applied only to particulate organic matter in sedimentary rocks, while biomarker parameters can be applied to both rocks and oils.
Biomarker thermal maturity ratios (solid black bars) respond in different ranges of the oil generation curve (Peters and Moldowan, 1993). Each ratio reaches an endpoint indicated by the number at the right end of the bar (%) and remains constant at higher maturities. The endpoint is the maximum value for most parameters except 18β/(18α+18β)-oleanane, βα/(αb+βα)-hopanes, and ββ/(ββ+αβ+βα)-hopanes, where the numbers 10, 5, and 0, respectively, are minimum values. Intermediate values within some bars correspond to earlier stages of...
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Bibliography
Peters, K.E. and Moldowan, J.M. (1993) The Biomarker Guide–Interpreting Molecular Fossils in Petroleum and Ancient Sediments. Englewood Cliffs, NJ: Prentice Hall, 363 pp.
Requejo, A.G. (1994) Maturation of petroleum source rocks–II. Quantitative changes in extractable hydrocarbon content and composition associated with hydrocarbon generation. Org. Geochem., 21, 91–105.
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© 1998 Kluwer Academic Publishers
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Peters, K.E. (1998). Biomarker: Assessment of thermal maturity. In: Geochemistry. Encyclopedia of Earth Science. Springer, Dordrecht. https://doi.org/10.1007/1-4020-4496-8_28
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DOI: https://doi.org/10.1007/1-4020-4496-8_28
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