Яндекс.Метрика

Alexey Kontorovich, Vladimir Kashirtsev, Vasilii Melenevsry, Irina Timoshina

Издание: 32nd International Geological Congress, Florence, Italy, August 20-28, 2004: Abstracts Volume
Место издания: Florence , Год издания: 2004
Страницы: 1394

Аннотация

The study of geochemistry of oils from Precambrian and Cambrian deposits of the Siberian platform has shown that all samples of oils are enriched in isotope 12C ('delta' 13C from -36.7 to -30.4o/oo) and by a number of genetic biomarker parameters can be divided into families. The family I oils localized in the sediments of the Baykit (R), Nepa-Botuoba (V-K1), and Katanga (V) petroleum areas are enriched in 12-, 13-monomethylalkanes (up to 18%), St29 steranes (up to 64%), Hh35 homohopanes relative to Hh34, T19-T31 tricyclanes (up to 81%) with a peak at the T23 compound and have low tricyclic index ITC = 2(T19+T20)/(T23+T24+T25+T26) - ranging 0.2 to 0.4. Alongside with these widely widespread oils, in the Angara-Lena (V-K1) and South Tunguska (K1) sediments the second family of oils has been identified, in which the 12-, 13-monomethylalkanes are present in trace amounts, St29 steranes do not prevail over other steranes, hopanes dominate among terpanes, Hh35 homohopane does not prevail Hh34 compound, among tricyclanes the T19 compound is present in high concentration and the ITC value reaches 1.2 or even 3.1. Besides these oils, in the Siberian platform identification of two more families related to the organic-rich Khatyspyt (V) and Kuonamka (K1-2) Formations localized in east of the Siberian platform is probable. Bitumoids of the Khatyspyt Formation are characterized by enrichment in 12C isotope and St29 steranes, low concentration of tricyclanes and absence of 12-, 13-monomethylalkanes. The same composition is found in bitumens of the Olenek uplift (V-K). Bitumoids of the Kuonamka Formation are also enriched in 12C isotope and tricyclanes, St29 steranes dominate over them, though not sharply, and also identified are vanadyl porphyrins. Similar characteristics have been revealed in the oil impregnating the cavernous limestones of the Tanhay Formation (K2) in the Bologur prospect (North Aldan petroleum area).The composition of the oils and bitumens from the Siberian platform revealed biochemical discrepancies in the lipid composition of source organic matter, conditions of its accumulation and diagenesis in the individual Precambrian and Cambrian environmental niches on the Siberian craton.
индекс в базе ИАЦ: 024376