Edwin  Ayuk Ndip, Christopher  M. Agyingi, Matthew  E. Nton, Michael  A. Oladunjoye, 
    Biomarker Geochemistry of the Lower Cretaceous Mamfe Formation Shale, Mamfe Basin,
Cameroon: Implications for Organic Matter Origin, Paleoenvironmental Conditions and
Thermal Maturity,
    Online Journal of Earth Sciences,
    Volume 14,Issue 4,
    2020,
    Pages 32-38,
    ISSN 1991-7708,
    ojesci.2020.32.38,
    (https://makhillpublications.co/view-article.php?doi=ojesci.2020.32.38)
    Abstract: The organic-rich shale of the Lower Cretaceous
Mamfe Formation is considered as an importantpetroleum
source rock in the Mamfe Basin. Biomarker geochemistry
of the shales was carriedout to evaluate the source of the
organic matter input, paleoenvironmental conditions
andthermal maturity. The investigated biomarker
indicated that the Mamfe sediments containterrigenous
organic matter with marine and lacustrine influences. The
Pr/Ph ratio that ranged from 0.60-1.71 and the
Gammacerane index of 0.07-0.23 are indicating sub-oxic
torelatively anoxic preservation of the organic matter.
Biomarker data revealed that C29 steranes (32.0-43.0 %)
are relatively more abundant than the C<sub>27</sub> (30.0-39.0%)
and C<sub>28</sub> (27.0-33.0%) steranes in the analysed shale
extracts which imply a substantial contribution of landplant
derived organic matter. The Oleanane index of
0.10-0.23 supports a predominance ofterrigenous organic
matter source in the sediments. Carbon Preference Index
of 1.0, Trisnorneohopane/Trisnorhopane (Ts/Tm) ratio
ranging from 0.33-0.63 and Moretane/Hopane(M/H) ratio
ranging from 0.16-0.27 showed that the shale&#146;s are
thermally mature with respectto hydrocarbon generation.
    Keywords: Mamfe formation;shale;biomarkers;organic matter;thermal maturity