GEOCHEMISTRY OF BIOMARKERS AND CATAGENESIS OF ORGANIC MATTER OF CRETACEOUS AND CENOZOIC DEPOSITS IN THE INDIGIRKA-ZYRYANKA BASIN ( northeastern Yakutia )
V.A. Kashirtseva, V.V. Gaidukb, O.N. Chalayac, and I.N. Zuevac
aA.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
bNK Rosneft Joint-Stock Company, ul. Krasnaya 54, Krasnodar, 350000, Russia
cInstitute of Oil and Gas Problems, Siberian Branch of the Russian Academy of Sciences, ul. Oktyabr'skaya 1, Yakutsk, 677891, Russia
Keywords: Indigirka-Zyryanka basin, Cretaceous and Paleogene-Neogene deposits, organic matter, biomarker molecule, oleanane
Pages: 787-797
Abstract
Organic matter of Cretaceous and Cenozoic deposits in the Indigirka-Zyryanka basin was studied by bituminological analysis and chromato-mass spectrometry. The regularities of distribution of alkanes and polycyclic aromatic hydrocarbons depending on the catagenesis of fossil organic matter are shown. Sesquiterpanes of the drimane series have been recognized in the Cretaceous deposits, and tetracyclic biomarkers of phyllocladane (kaurane), in the Cenozoic ones. The biomarkers were produced from terpenes of conifers, and the identified set of pentacyclic oleanenes are the products of angiosperms flourishing in the Paleogene and Neogene. As evidenced from geochemical indices, the Cenozoic deposits did not reach the PT -conditions of "the main oil formation zone" and should not be used for the quantitative evaluation of the regional petroleum potential. Nevertheless, the Cenozoic clayey units can be perfect isolating horizons for fluids migrating from more ancient, including Cretaceous, deposits.
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