E3 Journal of Scientific Research

E3 Journal of Scientific Research Vol. 2 (1) pp. 016-025, January 2014; © E3 Journals; ISSN 2276-9919

Biomarker evaluation of the oil generative potential of organic matter, in the upper Maastrichtian strata, Anambra Basin, southeastern Nigeria

Okeke HC¹, Orajaka IP¹, Anthony Okoro¹^*, Onuigbo EN¹
¹ Department of Geological sciences, Nnamdi Azikiwe University, P.M.B.5025, Awka, Nigeria
^*Corresponding Author E-mail: anthonyuokoro@yahoo.com
Accepted 10 December 2013

Abstract

Biomarker studies have been carried out on shale samples from the Upper Maastriachtian - Paleocene strata of Nsukka Formation in southern Anambra Basin. The samples were taken on a traverse from Ihube along the Enugu-Port Harcourt expressway through Okigwe to Umuasua near Ovim. Biomarker data from the shales indicate a dominance of intermediate molecular weight n-alkanes (nC12- nC33) and high pristane-phytane (Pr/Ph) ratios. The preponderance of pristane over phytane indicates that the organic matter may have been of humic and toxic to dysaerobic in origin. The n-alkane distribution patterns of the gas chromatograms are non unimodal and display maximum in the range nC12-nC33 with no significant humping implying little or no alteration of the organic matter. The carbon preference index (CPI) values range between 1.09 and 1.61.This means that the organic matter is immature and predominantly terrestrial.

Keywords: Biomarker, Kerogene, Maturity, Pristane, Phytane, Provenance

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