GeoActa Special Publication 1
2008
Acquisto online |
GeoActa
an international Journal of Earth Sciences
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Adel
Arfaoui, Mabrouk Montacer
Unité
de recherche «Géoressources, Environnements naturels et Changements
globaux», GEOGLOB code 03/UR/10-02, Université de Sfax, Faculté
des Sciences, route de Soukra, B.P 802 Code Postale. 3038, Sfax, Tunisie.
E-mail: arfmon@yahoo.fr, Mabrouk.Montacer@univgb.rnu.tn
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Triterpane
and sterane biomarkers in organic matter from Carnian organic-rich facies
in central and southern Tunisia
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PDF (312 KB)
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Abstract
Recent geochemical study of triterpanes and steranes
in free oils from Carnian Rheouis and Sidi Toui organic-rich
facies, in central and southern Tunisia, respectively, was performed
in order to characterize with accuracy their geochemical patterns. Biomarker
maturity parameters (i.e. Ts/Tm, 22S/(22S + 22R) of the C31
ab-hopanes
ratios, 20S/(20R + 20S) and bb/(bb
+ aa) of C29
steranes
), reveal that the organic-rich facies were deposited
during enhanced anoxic conditions in central and southern Tunisia. The
Upper Triassic outcrop samples generally contain type II organic matter,
which has already reached the stage of oil-generative window in the
two provinces.
This molecular correlation between these source rocks suggests slight
differences that can be the result of either the primary production,
the degree of conservation of the organic matter or thermal evolution.
On other hand, Rheouis and Sidi Toui could be promising areas for hydrocarbon
exploration in central and southern Tunisia.
Keywords:
Central
Tunisia; Southern Tunisia; Late Triassic; Source rock; Triterpanes;
Steranes; Anoxic event.
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