Boreskov

PP‐59matter (OM) of the Kuonamka Formation (collections of the Molodo R., Kyulenke R.). Themolecular parameters of the second biocommunity are as follows: steranes/terpanes ratio islower or equal to 0.1‐0.2; tricyclanes/hopanes ratio is lower than 1; steranes are dominatedby ethylcholestane; lanostanes and 28,30‐bisnorhopane are absent; С 29 /С 30 hopane ratio ishigher than 1. The С 35 /С 34 homohopane ratio is higher than 1, which is indicative ofhydrogen sulfide contamination of sediments and, possibly, bottom waters. Thesecharacteristics are peculiar to the OM of the Inikan Formation (collection of well Khotochu‐7). The third biocommunity: steranes/terpanes are at the level of 0.3; tricyclanes/hopanesare at the level of 1; steranes are dominated by ethylcholestane; lanostanes and 28,30‐bisnorhopane are absent; С 29 /С 30 hopane ratio is lower than 1. The С 35 /С 34 homohopaneratio is lower than 1. These parameters are typical of the OM of the Kuonamka and InikanFormations (collections of the Molodo R., Kyulenke R., well Khotochu ‐7). The fourthbiocommunity: generally, steranes/terpanes ratio is equal to 0.1‐0.2, andtricyclanes/hopanes ratio is lower than 0.1; steranes are generally dominated byethylcholestane; lanostanes and 28,30‐bisnorhopane have been identified; С 29 /С 30 hopaneratio is less than 1. The С 35 /С 34 homohopane ratio is greater than 1. These characteristics aretypical of the OM of the Sinyaya Formation (collection of the Sinyaya R.).Conclusion. The study of HCs from the rocks of the Kuonamka complex in the east of theSiberian Platform has made it possible to distinguish four ecological niches in the Lower andMiddle Cambrian seas. It has been established that biological communities and their habitatconditions either alternated in time, or changed, or remained stationary. The preliminaryestimation of the distribution of ecosystems in area extent has been performed from theresults of OM examination in four sections.This study was supported by the Russian Foundation for Basic Research (no. 10‐05‐00705), by the Leading Scientific Schools Grant of the President of the Russian Federation(no. NSh‐6244.2010.5), as well as by the Biosphere Origin and the Evolution of GeobiologicalSystems Program no. 15 of the Presidium of the RAS, and the ONZ‐1 Program of the RAS, byMultidisciplinary Integrative Project no. 36 of the SB RAS.References[1]. Kontorovich A.E., Savitsky V.Е. (1970) On paleogeography of the Siberian Platform in the Early and MiddleCambrian // Problems of lithology and paleogeography of Siberia [in Russian]. SNIIGGiMS. Novosibirsk.[2]. Ourisson, G., et al. (1984) The microbial origin of fossil fuels. Scientific American, 251, 44‐51.[3]. Parfenova T.M. (2007) In: II International Conference “Biosphere origin and Evolution”. Novosibirsk, p.194.[4]. Parfenova T.M. (2011) Doklady Earth Sciences, 436, 143‐147.[5]. Parfenova T.M., Pushkarev M.S., and Ivanova E.N. (2010) Doklady Earth Sciences, 430, 129‐133.[6]. Peters K.E., Moldowan J.M. (1993) The biomarker guide: Interpreting molecular fossils in petroleum andancient sediments. New Jersey, Prentis Hall, Engelwood Cliffs, 363 p.[7]. Revill A.T., Volkman J.K., O’Leary T. et al. (1994) Geochim. et Cosmochim. Acta, 58, 3803‐3822.237