Document Type

Article

Publication Date

1997

Journal / Book Title

International Journal of Coal Geology

Abstract

Organic-rich from the Schei Point group (middle to late Triassic in age) and the Ringnes formation (late Jurassic) from the Sverdrup basin of the Canadian arctic archipelago have been geochemically evaluated for source rock characterization. Most samples from the Schei Point group are organic-rich (> 2% TOC) and are considered as immature to mature oil-prone source rocks [kerogen types I, I-II (IIA) and II (IIA)]. These kerogen types contain abundant AOM1, AOM2 and alginite (Tasmanales, Nostocopsis, Leiosphaeridia, acritarch and dinoflagellate) with variable amounts of vitrinite, inertinite and exinite. Samples from the Ringnes formation contain dominant vitrinite and inertinite with partially oxidized AOM2, alginite and exinite forming mostly immature to mature condensate- and gas-prone source rocks [kerogen type II- III (IIB), III and a few II (IIA)]. Schei Point samples contain higher bitumen extract, saturate hydrocarbons and saturate/aromatic ratio than the Ringnes samples. Triterpane and sterane (dominant C30) distribution patterns and stable carbon isotope of bitumen and kerogen suggest that the analyzed samples from the Schei Point group are at the onset of oil generation and contain a mixture of sapropelic (algal) and minor terrestrial humic organic matter. Sterane carbon number distributions in the Ringnes formation also suggest a mixed algal and terrestrial organic matter type. There are some variations in hopane carbon number distributions, but these are apparently a function of thermal maturity rather than significant genetic differences among samples. Pyrolysis-gas chromatography/mass spectrometry of the two samples with similar maturity shows that the Schei Point sample generates three times more pyrolyzate than the Ringnes sample. Both samples have a dominant aliphatic character, although the Ringnes sample contains phenol and an aromaticity that is higher than that of the Schei Point sample.

Comments

This study delineates the comparative spatial distribution of organic facies, maturation and hydrocarbon potential for various organic-rich rocks from the Schei Point group and Ringnes formation sampled from borehole sections at different locations of the Canadian Arctic. It examines source rock quality, thermal maturity and genetic interrelationships of the organic matter using organic petrography, selected parameters from the Rock-Eval pyrolysis, wet chemistry, biological marker geochemistry, stable carbon isotope and pyrolysis-gas chromatography /mass spectrometry (py-GC/MS).

DOI

10.1016/S0166-5162(99)00065-8

Published Citation

Mukhopadhyay, P.K., Goodarzi, F., Kruge, M. A. and Alimi, M. H. (1997). Comparison of source rock geochemistry of selected rocks from the Schei Point group and Ringnes formation, Sverdrup basin, arctic Canada. International Journal of Coal Geology 34:225-260.

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