GeoActa Special Publication 1
2008
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GeoActa
an international Journal of Earth Sciences
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Adel Arfaoui, Mabrouk Montacer
Unite´ de recherche «Georessources, Environnements naturels et Changements globaux», GEOGLOB code 03/UR/10-02, Universite´ de Sfax, Faculte´ des Sciences, Departement de Geologie. B.P. 802, 3038 Sfax, Tunisia. E-mail: arfmon@yahoo.fr, Mabrouk.Montacer@univgb.rnu.tn
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Geochemical characterization of Lower Eocene organic-rich facies in Central-Northern Tunisia
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PDF (481 KB)
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Abstract
The study of Lower Eocene organic-rich facies at Chaker and Serj Jebels, in central-northern Tunisia, was carried out in order to characterize their geochemical fingerprint. It has been found that the organic matter is located towards the end of diagenesis-beginning of catagenesis. This assumption is supported by the relative low Tmax values (427-442ºC). The marine source fingerprint is predominant, as indicated by the high concentration of aliphatic hydrocarbons (13-91%), compared to aromatics (01-35%), and by the unimodal distribution of nalkanes centered on the light compounds (n-C18 to n-C20). TOC content varies from 0.49 to 3.12% and suggests a sufficient petroleum potential of Ypresian facies in each area. The occurrence of relatively anoxic conditions during the Ypresian led to the deposition of organic rich-facies in Chaker and Serj areas. These episodes were prone to preservation of good quantities of organic matter with relative high primary production. Due to their geochemical characteristics, the Lower Eocene facies represent a new potential source rock in central-northern Tunisia.
Keywords: Lower Eocene; Source rocks; TOC; Tmax; n-Alkanes; Anoxic conditions
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