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25th International Meeting on Organic Geochemistry IMOG 2011

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P-280<br />

Biomarker hydrocarb<strong>on</strong>s in schungites (Lower Proterozoic,<br />

Karelia)<br />

Aleksey K<strong>on</strong>torovich, Irina Timoshina, Tatyana Parfenova, Ananoliy Postnikov<br />

Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, Russian Federati<strong>on</strong> (corresp<strong>on</strong>ding<br />

author:TimoshinaID@ipgg.nsc.ru)<br />

In this study we examined organic matter (OM) of<br />

shungites (2100-1950 Ma) from the Lower Proterozoic<br />

Trans-Onega Formati<strong>on</strong> in the secti<strong>on</strong> of<br />

Zazhoginskaya-175 well within Onega synclinorium<br />

(the Baltic shield). TOC c<strong>on</strong>centrati<strong>on</strong>s in schungites<br />

from the well account for 1.6-27.5%, with δ 13 С ranging<br />

from ─39.7 to ─28.1 ‰, i.e. there was preserved<br />

carb<strong>on</strong> isotopic compositi<strong>on</strong> featuring mature marine<br />

polymer-lipid OM. The OM was metamorphosed to a<br />

stage of graphite (the atomic ratio (H/C)at of kerogen<br />

not exceeding 0.06-0.08), which is characterized by<br />

low c<strong>on</strong>tents of chloroform-extractable bitumens<br />

(0.007-0.021%). The main comp<strong>on</strong>ents of chloroformextractable<br />

bitumen are known to be saturated<br />

hydrocarb<strong>on</strong>s (HC) (35.9-60.7%) and resins (27.5-<br />

53.9%).<br />

In acyclic hydrocarb<strong>on</strong>s, the n-C27/n-C17 ratio of nalkanes<br />

and Pr/Ph ratio of isoprenoids range within<br />

0.0-0.1 and 0.5-1.1, respectively. C27 and C29 sterane<br />

c<strong>on</strong>tents are shown to be close, (С29/С27 ratio<br />

averages at 0.9-1.2), and the Dia/Reg ratio amounted<br />

to 0.3-0.4. In hopanes, the Ts/Tm (trisnorhopanes)<br />

and C35/C34 (homohopanes) ratios range within 0.9-<br />

1.1 and 0.6-0.8, respectively. In some samples, the<br />

tricyclane 2С19-20/С23-26 index rises to 1.8, it averages,<br />

however, at

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